iii computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1 may – 2021 eissn 2747-173x editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah endhah purwandari wenny maulina yoyok yulianto muhayat zamroni wiwin ro’inah computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index iii computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1 may – 2019 editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah endhah purwandari wenny maulina yoyok yulianto joko iswanto computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index iii computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1 november – 2018 editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah endhah purwandari wenny maulina yoyok yulianto joko iswanto computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index iii computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2 november – 2020 eissn 2747-173x editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah endhah purwandari wenny maulina yoyok yulianto joko iswanto computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index cerimre https://jurnal.unej.ac.id/index.php/cerimre eissn: 2747-173x physics department, faculty of mathematics and natural sciences the university of jember volume 4, issue 1 may 2021 table of contents volume 4, issue 1 may – 2021 eissn 2747-173x page cover i table of contents ii editorial board iii study of the structure and electronic properties of the zno monolayer: density functional theory muhammad fadlan raihan, triati dewi kencana wungu, and brian yuliarto 1-7 neutronic analysis of leu-started molten chloride fast reactor without fuel reprocessing r. andika putra dwijayanto and andang widi harto 8-20 analysis of vibration in payload room due to engine vibration on lsu-05 ng yusuf giri wijaya, nur mufidatul ula, muksin and mukhael gilang pribadi putra pratama 21-29 optimization of the main landing gear structure of lsu-02ngld fajar ari wandono 30-43 identification of the geothermal heat at mount iyang-argopuro based on a data image of landsat 8 satellite and a data gravity of ggmplus satellite ega abi bahtiar, agus suprianto and supriyadi 44-59 cerimre https://jurnal.unej.ac.id/index.php/cerimre eissn: 2747-173x physics department, faculty of mathematics and natural sciences the university of jember volume 3, issue 2 november 2020 table of contents volume 3, issue 2 november – 2020 eissn 2747-173x page cover i table of contents ii editorial board iii effect of tio2 addition on the electrical conductivity of nylon-tio2 hybrid membrane nurul octavia hijriyatur rohmah 47-52 analysis curie temperature and hysteresis la0.7sr0.3mno3 with micromagnetic simulation muhamad rony febiantoro, lutfi rohman and sutisna 53-57 simulation of co gas flow distribution due to chimney emissions using simflow 3.1 eka febriyani and nuroh hidayati 58-67 analysis of the effects of vortex generator on naca-4412 airfoil aerodynamics using the cfd method siti aisyah ayudia, artoto arkundato, lutfi rohman 68-74 numerical modeling of pressure source of sinabung volcano based on gps data in 2011-2012 using particle swarm optimization (ps0) ratih kumalasari, wahyu srigutomo, irwan meilano and hendra gunawan 75-81 cerimre https://jurnal.unej.ac.id/index.php/cerimre physics department, faculty of mathematics and natural sciences the university of jember volume 1, issue 1 november 2018 table of contents volume 1, issue 1 november – 2018 page cover i table of contents ii editorial board iii density of liquid lead as function of temperature and pressure based on the molecular dynamics method muhammad abdul bashar imanullah, artoto arkundato and endhah purwandari 1-6 characterization of carbon derived from water hyacinth as a renewable energy sources rani kusumaningtyas, wenny maulina and supriyadi 7-11 analysis of tensile strenght and shear modulus of gre pipe using ansys dita puspita, siti lailatul arofah, elok hidayah, lutfi rohman and ratna dewi syarifah 12-16 comparative analytic of viscoelasticity carbon, glass, and graphite fiber composite using maxwell model ro’sil khohar, umi sa’adah and dewi azzahra puspita 17-23 built in potential of a-si:h based p-i-n solar cell at different energy gap of intrinsic layer rahayu setyo yuniarsih, endhah purwandari, misto misto, edi supriyanto, supriyadi 24-29 cerimre https://jurnal.unej.ac.id/index.php/cerimre physics department, faculty of mathematics and natural sciences the university of jember volume 2, issue 1 may 2019 table of contents volume 2, issue 1 may – 2019 page cover i table of contents ii editorial board iii study of phenomenon stt (spin transfer torque) on permalloy nife material shaped nanowire using micromagnetic simulation khiptiatun ni’mah, lutfi rohman and endhah purwandari 1 – 9 effect of write head movement on magnetic spin domain reversal of nanocube co/pd alloy material using micromagnetic simulation ilham heru baskoro and merinda lestari 10 – 18 young’s modulus calculation of some metals using molecular dynamics method based on the morse potential fitriana faizatu zahroh, iwan sugihartono and ernik d. safitri 19 – 34 the effect of temperatur to electron concentration in the gaas crystal based p-n junction due to deformation potential scattering nova alviati, samsiatun hoiriyah, misto and edy supriyanto 35 – 44 modeling of ferrous metal diffusion in liquid lead using molecular dynamics simulation ahmad anwar nuris 45 – 55 12 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 12-16 submitted : september 3, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19544 analysis of tensile strenght and shear modulus of gre pipe using ansys dita puspita 1,a , siti lailatul arofah 1 , elok hidayah 1 , lutfi rohman 1 and ratna dewi syarifah 1 1 department of physics, faculty of mathematics and natural sciencs, university of jember, jalan kalimantan no 37 jember 68121, indonesia a ummusafiyah88@gmail.com abstract. composite materials (gre pipe) had been applied in various industries. these kind application are based on the advantages of composite properties, that are lightweight, high corrosion resistance and low cost. in order to make a lightweight and strong materials, some materials that light and stiff had been widely used, lie fiber glass, epoxy and the other. these materials (fiber glass and epoxy) are synthetic and non-biodegradable, but give some advantages in composite to make composite more stiff, light and strong. mechanical properties of fiber glass composites had been doing based on theory through modeling. theoretical results obtained showed that maximum stress and shear modulus value of gre pipe are less than each components (glass fiber and epoxy resin). each value of maximum stress and shear modulus are 584.57 mpa and 46.15 mpa. keywords: composite material, ansys, gre pipe introduction composite material is a material consisting of two or more constituent materials which physically and mechanically can be distinguished from one another [1]. composite material consists of two main components, namely reinforcement and matrix. reinforcement is a component that determines the strength and stiffness of the composite material. while the matrix is a material that functions to bind and protect the composite material from external influences [2]. composite materials have been widely applied in various industrial fields [3,1] because of their relatively cheap production costs, strength, light weight, and resistance to corrosion [4]. one of the applications of composite materials is the oil and gas industry pipes. metal pipe is a pipe that is often used in the oil and gas industry because of its excellent strength. however, metal pipes also have disadvantages, namely low corrosion resistance. especially for the offshore oil and gas industry, corrosion problems in pipes often occur both inside and outside the pipe. corrosion of the inner pipe usually occurs due to the reaction between the pipe building materials and gases such as carbon dioxide (co2) and hydrogen sulfide (h2s) [5]. due to corrosion in pipes causing several operational and health problems which are commonly referred to as the cases of capex and opex (capital and operational expenditures) and hse (health, safety, and the environment) in the oil and gas industry. most of the reported corrosion was due to carbon dioxide gas and caused a 25% safety incident problem, 2.2% real assets, an 8.5% increase in capital expenditure, a 5% loss / deferred production, and an 11.5% increase in pipeline lifting costs [6]. therefore a pipe with strong mechanical properties and corrosion resistance is needed. 13 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 12-16 submitted : september 3, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19544 one type of pipe that suits these conditions is a pipe made of gre (glass reinforced epoxy) composite material, which is a composite material with a matrix in the form of epoxy and a glass fiber reinforcement [7]. epoxy is used as a matrix because it has the best chemical resistance among other resins (isophatalic polyester, vinyl ester, and phenolics) [8]. gre pipes are designed to withstand high pressure, light weight, and have high strength so that they can be properly applied to the oil and gas industry. the use of gre composite materials for the manufacture of oil and gas industry pipes needs to pay attention to its mechanical properties. mechanical properties are parameters used to determine the strength and suitability of a material before it is applied as a product. the test used is the tensile test. through the tensile test it can be seen the tensile strength and modulus of elasticity of the material [9]. tensile strength is the maximum tensile stress a material can accept without causing local fracture [10]. while the modulus of elasticity is a mechanical property that shows the stiffness of a material. the greater the modulus of elasticity, with the application of the same force, the material will experience a slight change compared to materials with a small modulus of elasticity [11]. gre pipe testing is done using ansys software. ansys is a program used to model finite elements to solve cases related to mechanics, including static, dynamic, fluid structural analysis, as well as cases related to acoustics and electromagnetics. testing is done by making the pipe geometry and then inputting the gre material parameters. testing by means of modeling is carried out to obtain an estimate of the material and its mechanical properties before the experiment is carried out, so that the results of the modeling can be used as a consideration when conducting experiments. method the first step is making a model by inputting data in the form of pipe geometry and gre material parameters in ansys 18.2 software, input parameters such as modulus of elasticity. poisson ration, thickness, radius, length, and density are inputted. then do the meshing process. because the method used in ansys is the finite element method, when meshing the geometric surface it will be divided into small squares (1835 nodes and 1518 elements). the next step is to input the boundary conditions on the pipe geometry that has been made. then tested and then analyzed the results. results and discussion composite material synthesis is one of the methods used to improve the mechanical properties of each component of the composite material. analysis of the mechanical properties of composite materials can be done directly through experiments, and indirectly by modeling. modeling is one way that can be done to estimate the shape and mechanical properties of the materials to be made, so that the determination of materials for certain applications becomes easier. in this research, glass fiber and epoxy resin are combined to manufacture gre (glass reinforce epoxy) pipes. the geometry obtained based on the modeling results is shown in figure 1. 14 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 12-16 submitted : september 3, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19544 figure 1. the geometry of the gre pipe the resulting gre pipe has an inner diameter of 20 cm, an outer diameter of 22 cm, a height of 30 cm and a thickness of 2 cm. the tensile test is carried out by determining the points on the pipe as the location to be drawn, the direction of pull and the static point of the pipe. the static point is the part of the pipe that is fixed or not moving, because in this simulation the pulling force is only applied to one end of the material, while the other end is fixed. there are several mechanical properties produced by modeling this gre pipe, including maximum tensile stress, maximum strain, maximum deformation and shear modulus. modeled gre pipe has a maximum tensile stress of 584.57 mpa, as shown in figure 2. this value is still smaller than the maximum tensile stress possessed by glass fiber and epoxy resin. some things that may affect the maximum tensile stress value are the meshing size that is too large, so it does not represent all elements in the pipe. another factor is the geometry of the material in the form of a hollow pipe. the presence of a cavity may contribute to the reduced mechanical properties of the synthesized composite material. the shear modulus produced by gre pipe is 46.15 mpa. in addition to the tensile stress value, the maximum strain and maximum deformation values of gre pipe are obtained as shown in figure 3 and figure 4. the maximum strain and maximum deformation values of gre pipe are respectively 7.45% and 0.1058 cm. figure 2. the maximum tensile stress of the gre pipe 15 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 12-16 submitted : september 3, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19544 figure 3. the maximum strain of the gre pipe figure 4. maximum deformation of gre pipe summary research on the analysis of the tensile strength and shear modulus of gre pipes has been carried out. the tensile stress value resulting from the modeling is still far different from the maximum tensile stress of epoxy resin and glass fiber. due to the small tensile stress, the shear modulus is also small. this is presumably due to the large size of the meshing. therefore, further research can be carried out with a smaller meshing size in order to obtain results with better accuracy. references [1] n sridhar, d s dunn, a m anderko, m m lencka and h u schutt, 2000, effect of water and gas compositions on the internal corrosion of gas pipelines modeling and experimental studies, corrosion, volume 57(3). [2] j m berthelot, 1999, composite materials: mechanical behavior and structural analysis, new york, springer. 16 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 12-16 submitted : september 3, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19544 [3] p a fowler, j m hughes and r m elias, 2006, biocomposites: technology, environmental credentials and market forces, journal of the sciences of food and agricultures, volume 86, page 1781 – 1789. [4] m akay, 2015, an introduction to polymer-matrix composites, http://www.bookbon.com, accessed january 11, 2018. [5] p wambua, j ivens and i verpoest, 2003, natural fiber: can they replace glass in fiber reinforced plastics, composites science and technology, volume 63, page 1259 – 1264. [6] m b kermani and a morshed, 2003, carbon dioxide corrosion in oil and gas production-a compendium, corrosion, volume 59(8). [7] s r frost and a cervenka, 1994, glass fibre-reinforced epoxy matrix filament-wound pipes for use in the oil industry, composit manufacturing, volume 5(2). [8] n himawan, i rochani and h ikhwani, comparative analysis of onshore pipeline design using material glass reinforced polymer (grp) and carbon steel based on techno echonomic. [9] j r davis, 2004, tensile testing second edition, usa: asm international. [10] m ohring, 1995, engineering materials science, california: academic press inc. [11] d roylance, 2008, mechanical properties of materials, usa: mit. http://www.bookbon.com/ 1 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 1-6 submitted : august 20, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19541 density of liquid lead as function of temperature and pressure based on the molecular dynamics method muhammad abdul bashar imanullah 1 , artoto arkundato 1,a and endhah purwandari 1 1 physics department, faculty of mathematical and natural sciences, jember, indonesia a a.arkundato@unej.ac.id abstract. simulation research has been carried out to obtain the formula for mass density of liquid lead as a function of temperature and pressure. the simulation method used is the molecular dynamics method. the potential energy used in the simulation is the morse potential. from the simulation, it is found that the relationship between the mass density of liquid lead and temperature and pressure can be expressed in the equation for pressure 1 – 5 atm and for pressure 7 atm in units kg/m 3 . keywords: liquid lead, mass density, temperature, pressure, molecular dynamics. introduction currently, nuclear power plants have become one of the alternative energy sources which are becoming an interesting choice of many countries. if developed countries have long used nuclear energy to support their heavy industries, developing countries think about the use of this energy in a recent time. the nuclear reactor basically produces heat energy from the process of nuclear fission. the subsequent use in the form of conversion to electricity in large quantities is one of the attractions for the development of this nuclear energy, besides there may concerns for utilization in the field of weaponry. the development of nuclear reactors for welfare today generally still relies on the design of thermal reactors. there are still many thermal reactors operating in this world. unfortunately, many thermal reactors are still legacy of old designs. since the chernobyl nuclear reactor accident in ukraine in the past, a safer new concept reactor design is constantly being considered. for this reason currently developing iv generation nuclear reactors. some of the advantages of this generation iv reactor design are the inherent safety concept. liquid metal-cooled fast nuclear reactors, for example liquid lead, are reactor concepts and designs that apply the safety concept inherent in the design so that if there is a potentially catastrophic anomaly in the reactor, the reactor system can automatically shut down the operation of the nuclear reactor without the need for any process of manual shutdown. more specifically, the liquid lead metal cooled fast nuclear reactor is one of the promising reactor concepts apart from applying the inherent safety concept it is also capable of being made in a modular form and producing high power energy [1]. 2 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 1-6 submitted : august 20, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19541 liquid lead metal and its alloys with other metals such as bismuth are currently promising candidate materials for cooling fast nuclear reactors [2]. there are many advantages compared to cooling water in a slow neutron nuclear reactor. one of them is that it has a high boiling point and has a large thermal conductivity, making it very suitable for cooling in fast reactor designs. for this reason, in order for the design of a fast nuclear reactor to be made properly, complete nuclear data, for example, information on mass density, is required. because in the reactor two factors that are very important to note are temperature and pressure, this mass density needs to be known as a function of temperature and pressure. in this study, therefore, we want to know the density formula as a function of temperature and pressure. to obtain this, the molecular dynamics method will be used so that a lot of data can be obtained for various temperatures and pressures. theory molecular dynamics methods in general can be used to predict the physical properties of materials such as melting point, heat conductivity, enthalpy, diffusion coefficient, and so on, including predicting density as a function of temperature. what matters is whether we have sufficient potential energy data to describe the interactions between the atoms of the material system. arkundato et al has used the molecular dynamics methods to investigate liquid lead coolant [3-4]. in this research, we will use the morse potential. in the molecular dynamics method, the newton motion equation is solved to get the trajectories of all the atoms that make up the material. the relationship between newton's equations of motion and potential is as follows f = m d 2 r/dt 2 (1) f = dv/dr (2) where f is the interacting force of particles, r position vector of a particle, v is potential energy of interacting particles. the morse potential for this simulation has a form of [5]. ( ) e ( ) (3) where re is the equilibrium bond distance from the atom, de is the bonding energy balance of an atom and a is a parameter, √ (4) girifalco dan weizer (1958) has made table of morse potential parameters as below [6]. 3 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 1-6 submitted : august 20, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19541 table 1. morse potential parameters of some cubic metals [5] metal ( ) d(ev) pb 2.921 83.02 7.073 1.1836 3.733 0.23480 ag 2.788 71.17 10.012 1.3690 3.115 0.33230 ni 2.500 51.78 12.667 1.4199 2.780 0.42050 cu 2.450 2.450 49.11 10.330 1.3588 0.34290 al 2.347 4417 8.144 1.1646 3.253` 0.27030 ca 2.238 39.63 4.888 0.80535 4.569 0.16230 sr 2.238 39.63 4.557 0.73776 4.988 0.15130 w 2.225 72.19 29.843 1.4116 3.032 0.9906 cr 2.260 75.92 13.297 1.5721 2.754 0.4414 fe 1.988 51.97 12.573 1.3885 2.845 0.4174 in our work we will use morse potential parameter from girifalco data. furthermore, based on the trajectory of the atoms of the material as a solution of newton's equations of motion then using statistical mechanics concepts and theories it can be predicted any physical quantities that we want to know. this physical quantities can be calculated easily when we use the lammps molecular dynamics software [6] that also we used in this research (https://lammps.sandia.gov/). method the purpose of this study was to find the mass density relation of liquid lead as a function of temperature and pressure. physical variables mass density, pressure, temperature were simulated with lammps software. the procedure for obtaining the relationship between the three variables is carried out according to the following steps: 1. create a script file that contains data on the position of lead atoms, mass, number of atoms, pressure, temperature, number of integration steps, compute command, etc. table 2 is a summary of input parameters. table 3. input parameters for lammps simulation variable value mass of pb 207.2 lattice constant 4.950 temperatures 323 , 423 , 523 , 623 , 723 , 823 , 923 , 1023 d 0.2648 ev 3.520 1.3036 pressure 1 atm, 5 atm, 7 atm 2. do simulation for different temperature and pressure 3. make analysis and conclusion 4. determine mass density as a function of temperature and pressure 4 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 1-6 submitted : august 20, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19541 results from lead simulation results for different temperatures and pressures then we can calculated the density as table 4. table 4. density of liquid lead at various temperatures and pressures temperature (k) mass density (kg/m 3 ) pressure1 atm pressure 5 atm pressure 7 atm 323 10918.59013 10918.71963 10918.78437 423 10839.89903 10840.03266 10840.09959 523 10758.77752 10758.90916 10758.97953 623 10673.75396 10674.02894 10674.10180 723 10582.58427 10582.73939 10582.81616 823 10479.97194 10480.13611 10481.66200 923 10356.97857 10357.16451 10357.58981 1023 10189.90371 10190.05928 10190.47230 from table 4 we can determine the mass density as a function of temperature and pressure using linear regression method, for pressure 1 atm: [1 atm] [5 atm] (5) equation (5) also applies for pressure 5 atm. for pressure 7 atm there is a little different, i.e., [7 atm] (6) figure 1 shows the mass density of liquid lead at 1 atm as a result of molecular dynamics simulation. figure 1. mass density of liquid lead at 1 atm ρ = 11233-0.9217 x t r² = 0.9937 10300 10400 10500 10600 10700 10800 10900 11000 0 200 400 600 800 1000 ρ (k g /m 3 ) t (k) 5 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 1-6 submitted : august 20, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19541 let’s we compa e ou simulation esult and a reference [7]. sobelov states that the formulation value for the density of liquid lead at a pressure of 1 atm is: [1 atm] (7) we can check the discrepancy between simulation and reference as shown in table 5. table 5. comparison the mass density by simulation and reference temperature (k) mass density (kg/m 3 ) (simulation) mass density (kg/m 3 ) (sobelov, 2011) discrepancy (%) 323 10935,2909 10997,7215 0,57% 423 10843,1209 10869,7715 0,25% 523 10750,9509 10741,8215 0,08% 623 10658,7809 10613,8715 0,42% 723 10566,6109 10485,9215 0,77% 823 10474,4409 10357,9715 1,12% 923 10382,2709 10230,0215 1,49% from table 5 we can conclude that our simulation results are pretty good when compared to references. in our simulation we have used 500,000 atoms of pb created by 50 x 50 x 50 boxes of unit cells in fcc crystal structure. then this also describes that the morse potential and its parameters is good to formulate the interaction among metallic atoms of lead. conclusions the simulation results are pretty good when compared to references. the simulation method used is the molecular dynamics method. the potential energy used in the simulation is the morse potential. in our simulation we have used 500,000 atoms of pb created by 50 x 50 x 50 boxes of unit cells in fcc crystal structure. then this also describes that the morse potential and its parameters is good to formulate the interaction among metallic atoms of lead. from the simulation, it is found that the relationship between the mass density of liquid lead and temperature and pressure can be expressed in the equation for pressure 1 – 5 atm and for pressure 7 atm in units kg/m 3 . references [1] t sofu, 2015, a review of inherent safety characteristics of metal alloy sodium-cooled fast reactor fuel against postulated accidents, nuclear engineering and technology, volume 47, issue 3, pages 227-239. [2] j zhang, n li, 2008, review of the studies on fundamental issues in lbe, journal nuclear mater, volume 373, page 351-377. [3] kundato. z su’ud, abdullah and widayani, 2013, molecular dynamic simulation on iron corrosion reduction in high temperature molten lead-bismuth eutectic, turk. j. phys, volume 37, page 132-144. https://www.sciencedirect.com/science/article/pii/s1738573315000753#! https://www.sciencedirect.com/science/journal/17385733 https://www.sciencedirect.com/science/journal/17385733/47/3 https://www.sciencedirect.com/science/journal/17385733/47/3 6 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 1-6 submitted : august 20, 2018 accepted : october 10, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19541 [4] kundato, z su’ud, m abdullah, w sutrisno and m celino, 2013, inhibition of iron corrosion in high temperature stagnant liquid lead: a molecular dynamics study, annals of nuclear energy, volume 62, page 298-306. [5] d d abajingin, 2012, solution of morse potential for face centre cube using embedded atom method, advance in physics theories and applications, volume 8, page 36-44. [6] l a girifalco, v g weizer, 1959, application of the morse potential function to cubic metals, physical review, volume 114(3), page 687-690. [7] s plimpton, 1995, fast parallel algorithms for short-range molecular dynamics, j comp phys, volume 117, page 1-19. [8] v sobelov, 2011, database of thermophysical properties of liquid of metal coolats for gen-iv, belgium, skc.cen. 24 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 24-29 submitted : september 11, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19547 built in potential of a-si:h based p-i-n solar cell at different energy gap of intrinsic layer rahayu setyo yuniarsih 1 , endhah purwandari 1,a , misto 1 , edi supriyanto 1 and supriyadi 1 1 department of physics, faculty of mathematics and natural sciencs, university of jember, jalan kalimantan no 37 jember 68121, indonesia a endhah.fmipa@unej.ac.id abstract. the photovoltaic process inside a solar cell can be described using the distribution of electrostatic potential in the material. in this paper, the magnitude of the electrostatic potential of the solar cell for the p-i-n junction type is analyzed as the built in potential due to the diffusion activity of electrons and holes. the magnitude of the electrostatic potential is obtained by solving the poisson and continuity equations, which are applied to a-si: h based materials. the difference in built in potential at the p-i and in junctions is obtained as a function of the energy gap of the intrinsic layer. keywords: solar cell, electrostatic potential, built in potential, energy gap introduction hydrogenated amorphous silicon (a-si:h) based solar cells having p-i-n structure have been widely investigated for use as low-cost solar cells [1]. they have also been made using a simple method and an abundance of materials [2]. as an electric power source, a-si:h p-i-n solar cells requires improvements in collection efficiency and stability. the performance parameters are determined by open-circuit voltage (voc), short-circuit current (isc), fill factor (ff) and efficiency (η). one of the factors that can increase the short circuit current density is the number of charge carriers generated in the device, due to the photogeneration mechanism.the more increased the number of charge particle generated, the more enhanced the short circuit current produced. the greatest number of photogeneration process are created in depletion area, where the intrinsic layer plays a major role in the occurrence of the process. built-in potential generated two conjunctions of intrinsic layer and the two outer layer determines the width of depletion area. the energy gap possessed by the intrinsic layer affects the photogeneration rate produced by the layer. in this paper, various number of energy gap of intrinsic layer have investigated to analyze their effect to the built in potential. theoretically, transport mechanism of charge carriers in semiconductor devices is well described using poisson and continuity equations [3]. their numerical solution defines the carrier charge of semiconductor as function of potential electrostatic at operational temperature. having known the electrostatic potential at the point of the junction in p-i-n solar cell, we can find out the magnitude of the built in potential in it. the study of hydrogenated amorphous siliconbased solar cells in modelling area had investigated since early 1980's. in one-dimensional structure, the conversion mechanism of solar cells has been analyzed by hack and shur [4], tareto et al. [5] zhu et al. [6], kabir et al. [7], usman [8] and purwandari [3]. 25 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 24-29 submitted : september 11, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19547 the measurement of built in potential has been experimentally measured by olthof using ultraviolet photoemission spectroscopy (ups) method. he had investigated built in potential in p-i-n homojunction of pentacene.the results showed that the potential in p-i junction was greater than i-n junction [9]. in this research, the built in potential calculation has been carried out using a numerical approach based on the finite element method. the ease of application of the finite element method is a suitable choice for theoretical studies of solar cells. the finite element method is used to analyze the built-in potential in solar cells with the p-i-n connection type for variations in the energy gap and output voltage. methods a single junction p-i-n amorphous silicon solar cells was presented in one dimensional physically-based computer simulation using finite elemen method laboratory (figure 1). the simulator was applied to the analysis of a p-i-n single junction a-sic:h/a-si:h/a-si:h solar cell. the lengths of the p, i and n layer were set at a thickness of 0.015 µm, 0.55 µm and 0.03 µm respectively. the energy gaps of the p and n layer were 2.36 ev and 1.7 ev. in this simulation, the effects of energy gap of intrinsic layer to built in potential were analyzed by varying them from 1.70 to 1.74 ev. the extracted features shown in table 1 are used as the input parameter of simulation. figure 1. one dimensional structure of single junction p-i-n a-si:h. boundary 1 and 4 are interface between metal and device, where boundary 2 represents the interface between layer p and i and boundary 3 represents the interface between layer i and n we have used the modified poisson and continuity (for electrons and holes) equations [8]. they were modelled to take account the potential electrostatic considering doping concentration, free charge carrier and its trapped component in amorphous structure. the boundary condition applied to the structure involve the contact and non contact device area to metal. we have applied dirichlet boundary condition to define the magnitude of potential and charge carrier concentration which passed through the junction of p and n layers to the metal contact and also for intra-connection between p-i-n layers. its electrostatic potentials of the material were calculated as the sum of the external voltages and the logarithmic energy equation which corresponds to changes in dopant concentration [8]. for other boundaries, neumann condition have applied [10]. 26 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 24-29 submitted : september 11, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19547 table 1. input parameters of simulation parameters value permitivity ( ) 11.8 f/cm temperature (t) 300 k flux of photon ( ) 10 17 cm -2 s -1 transmission factor (p) 0.71 light absorbtion coefficient of a-si (α) 22222 (cm -1 ) intrinsic concentration (ni) 6.019 x 10 10 cm -3 donor concentration (nd) 8.8 x 10 17 cm -3 acceptor concentration (na) 1 x 10 17 cm -3 electron diffusion (dn) 40 cm 2 /s electron diffusion (dp) 4 cm 2 /s rasio between ionize and neutral charges (c) 50 thermal velocity by neutral bonding (vthσn) 10 -11 cm -3 s -1 minimum density at donor and acceptor (gmin) 10 16 cm -3 ev -1 donor energy (ed) 0.088 ev acceptor energy (ea) 0.053 ev minimum energy of conduction band (emc) 0.65 ev energy of valence band (ev) 0.15 ev mesh 0.00145 result and discussion the accumulation of charges in the junction area creates an electrostatic potential. the simulation results are electrostatic potential data on all parts of the device. the performance of the potential data for a p-i-n junction device is shown in figure 1 and presented for a voltage of 0 v where the band gap energy of intrinsic part is 1.7 ev. from both ends of the device terminal, the potential difference is almost 0 v. the curve produces the high increment when the program was taken into account for p and i layers. the dopant addition in these layers causes the increase potential, based on the poisson equation, while the intrinsic semiconductor have contributed to change of electrostatic potential at the middle part of the device. to observe the effect of difference of energy gap applied to the intrisic layers, we need to determine all potential data produced at the junction layers. 27 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 24-29 submitted : september 11, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19547 figure 1. profile of electrostatic potential of a-si:h p-i-n junction solar cell with the thickness of 0.015 µm /0.55 µm/0.03 performed at band gap energy of intrinsic part of 1,7 ev and terminal voltage of 0 v figure 2. built in potential at the p-i junction when the energy gap of the intrinsic layer is varied by 1.70 ev, 1.72 ev and 1.74 ev -11,50 -11,00 -10,50 -10,00 -9,50 -9,00 -8,50 -8,00 -7,50 -7,00 1,70 1,72 1,74 b u il t in p o te n ti a l (v ) band gap energy (ev) va = 0 v va = 0.1 v va = 0.2 v va = 0.3 v va = 0.4 v va = 0.5 v 28 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 24-29 submitted : september 11, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19547 the data of built in potential obtained by the simulation perform that all band gaps of intrinsic layer are negative numbers. these has a good agreement that negative charges were accumulated at the junction of p and i layers. at energy gap of 1,72 ev, the increasing built potential takes place only on terminal output of 0v. the highest built in potential were supported by the number of carrier charge. but this condition were not staying longer when the energy rising up to 1.74 ev. figure 3. built in potential at the i-n junction when the energy gap of the intrinsic layer is varied by 1.70 ev, 1.72 ev and 1.74 ev all built in potential data is positive, which means that the hole dominates the charge carrier in the i-n junction area. almost all potential data decreased when the energy gap of layer i was increased by 1.72 ev. when the energy gap of layer i is increased to 1.74 ev, the built in potential calculation for all output voltage data has decreased, except for the voltage of 0.2 v. conclusion the electrostatic potential distribution of amorphous silicon based solar cells, with a p-i-n linkage structure, has different profiles when analyzed at various output voltages. negative potential performs electron charges accumulated at the junction of p and i layers, where its positive number represent the hole charges at i-n junction. the application of different energy gaps in the i-layer has a significant effect on the built-in potential of the two junctions (p-i and in). the device has a significant change in built in potential when the output voltage is 0 v. when the energy gap of layer i is 1.72 ev, the device has the highest potential and then drops drastically at 1.74 ev. a decrease in built in potential due to an increase in the energy gap of the intrinsic layer occurs at all output voltages, except at 0.3 v. 0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,70 1,72 1,74 b u il t in p o te n ti a l (v ) energy gap (ev) va = 0 v va = 0.1 v va = 0.2 v va = 0.3 v va = 0.4 v va = 0.5 v 29 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 24-29 submitted : september 11, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19547 references [1] r kaplan and b kaplan, 2001, built-in potential measurements in a-si:h p-i-n solar cells, turk j phys, volume 25, pp 375 – 383. [2] a siregar, 2011, pengaruh konsentrasi ekstrak antosianin pomegranate fruits (buah delima) sebagai dye-sensitizer terhadap efisiensi sel surya jenis dssc (dye sensitized solar cell,. jakarta, universitas pendidikan indonesia [3] e purwandari and t winata, 2012, optimasi tekanan deposisi dalam simulasi efisiensi sel surya, gradien, volume 8(1), page 716-721. [4] m hack and m shur, 1985, physics of amorphous silicon alloy p-i-n solar cells. j. appl. phys., volume 58(2), page 997-1020. [5] k taretto, u rau, and j h werner, 2003, closed-form expression for the current/voltage characteristics of pin solar cells, appl. phys. a., volume 77, page 865-871. [6] zhu, kalkan, hou, and fonash, 1999, application of amps-1d for solar cell simulation. the america institute of physics, volume 4(1), page 309-314. [7] kabir, shahahmadi, lim, zaidi, sopian, and amin, 2009, amorphous silicon singlejunction thin-film solar cell exceeding 10% efficiency by design optimization, international journal photoenergy, (460919)7. [8] i usman, 2006, penumbuhan lapisan tipis silikon amorf terhidrogenisasi dengan teknik hwc-vhf-pecvd dan aplikasinya pada sel surya, disertasi, bandung: itb. [9] olthof, kleeman, lussem, and leo, 2010, built-in potential of a pentacene p-i-n homojunction studied by ultraviolet photoemission spectroscopy, matter. res. soc. symp. proc., 1270-(2), 09-49. [10] e purwandari and t winata, 2013, efficiency calculation analysis of a-si:h solar cells for determination of optimum filament temperature in material deposition, jurnal ilmu dasar, volume 14(1), page 29-32. 75 computational and experimental research in materials and renewable energy (cerimre) volume3, issue2, page 75-81 eissn : 2747-173x submitted : august 21, 2020 accepted : october 11, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23549 numerical modeling of pressure source of sinabung volcano based on gps data in 2011-2012 using particle swarm optimization (ps0) ratih kumalasari 1,a , wahyu srigutomo 2 , irwan meilano 2 and hendra gunawan 3 1 universitas bhayangkara jakarta raya, jl. harsono rm dalam no.46 ragunan ps. minggu kota jakarta selatan 12550, indonesia 2 institut teknologi bandung, jl. ganesa no. 10 bandung 40132, indonesia 3 pusat vulkanologi dan mitigasi bencana, jl. diponegoro no.57 cihaur geulis bandung, indonesia a ratih.kumalasari@dsn.ubharajaya.ac.id abstract. mogi model with particle swarm optimization (pso) scheme have been applied to the local gps data of sinabung volcano during 2011 to 2012 to receive subsurface parameters as pressure sources in terms of misfit and inversion model parameter. the size of displacement was inverted by pso. from the inversion concluded that the position pressure source showing shallow magma pockets at a depth between ±1.3 km volume changes around 6 3 0.95 10 m  . it indicates the presence of a huge magma supply and continuous into shallow magma chamber up to the surface of sinabung volcano. keywords: pressure source, pso, mogi models, sinabung introduction indonesian territory is located at the confluence of several tectonic plates involve the eurasian plate, the indo-australian plate and the pacific plate. this position causes subduction activity so that many volcanoes are appeared in indonesia, one of which is sinabung volcano. sinabung volcano is a strato type volcano that is administratively located in karo regency, north sumatra province, with a peak of 2,460 m above sea level, with coordinates 3° 10' lu and 98° 23.5' bt [1]. before 2010 sinabung volcano was a type b volcano, which had not been erupted since 1600s, but still exposed volcanic activities such as the presence of solfatar or fumarole fields. the eruption activities of sinabung volcano have just been recorded since august 2010 which makes it as type a volcano. later, continuous monitoring is done to mitigate the danger of the eruptions. volcanic eruption activity is generally preceded by early symptoms or precursors, such as increased seismic activity, increased temperature of hot springs, changes in composition and strength of gas gusts, as well as the existence of deformations in the body of the volcano. proper monitoring on the activities of a volcano requires input data from various methods, one of which is a deformation monitoring method by gps data [2-4]. 76 computational and experimental research in materials and renewable energy (cerimre) volume3, issue2, page 75-81 eissn : 2747-173x submitted : august 21, 2020 accepted : october 11, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23549 theoretical background in this study we used the mogi model (point pressure) [5], mogi model (1958) assumes that the earth's crust is a semi-elastic medium and the deformation is caused by a point pressure at a certain depth. if there is a hydrostatic change in the ball, symmetrical deformation will occur. it is explained in the volcano deformation that the displacement on the surface caused by changes in hydrostatic pressure in the cavity of the earth's crust with a radius smaller than the depth )( da  are stated in equation 1 [6].                               3 3 3 3 1 r z r y r x g p w v u   (1) where d is the depth of the pressure source, r is the radial distance of the pressure source to the monitoring point,  is the poisons ratio, g is the shear modulus, and p is the change in pressure, as graphically illustrated in figure 1. figure 1. mogi model materials and methods the data that we used is devide into 2 period: 1. 1 st period (1st april 2011 – 22nd july 2011). 2. 2 nd period (22nd july 2011 – 4th march 2012). table 1. changes of position in each period period station coordinat displacement (m) standard deviation x y z x y z x y z 1 lkwr 431687.15000 352794.03000 1496.45190 -0.00531 0.00028 0.01615 0.01133 0.00883 0.03255 sknl 434757.39000 351034.54000 1442.59190 -0.00735 0.00104 0.01626 0.01177 0.00878 0.03182 grki 432671.64000 347790.79000 1230.30610 -0.00496 0.00274 0.01270 0.01026 0.00760 0.02874 snbga 440477.08000 347201.59000 1248.57910 -0.00659 0.00057 0.00783 0.00906 0.00731 0.02477 2 lkwr 431687.15000 352794.03000 1496.45190 -0.00413 -0.00072 0.03726 0.00912 0.00754 0.02703 sknl 434757.39000 351034.54000 1442.59190 -0.00003 0.00064 0.03238 0.01004 0.00728 0.02925 77 computational and experimental research in materials and renewable energy (cerimre) volume3, issue2, page 75-81 eissn : 2747-173x submitted : august 21, 2020 accepted : october 11, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23549 period station coordinat displacement (m) standard deviation x y z x y z x y z grki 432671.64000 347790.79000 1230.30610 -0.00500 -0.00053 0.02528 0.00868 0.00708 0.02702 snbga 440477.08000 347201.59000 1248.57910 -0.00019 -0.00027 0.02590 0.00584 0.00453 0.02537 we use particle swarm optimization (pso) to characterize the pressure source parameters of sinabung volcano. particle swarm optimization (pso) is an optimization algorithm that mimics the processes in the life survival of a flock of bird and a school of fish developed by james kennedy and russell eberhart in 1995 [7-8]. in pso, the population is assumed to be a particle with certain size and located at a random location in a multidimensional space. at the initial position of each particle is assumed to have two characteristics, namely position and speed. each particle moves in a certain space and remembers the best position (pbest) that has ever been passed or found against food sources or the value of an objective function, each particle then conveys its information or best position to other particles and adjusts its position and speed based on information received regarding the best position (gbest). the position and velocity adjustment for each particle is formulated in equation 2 and equation 3. (2) (3) which ( 1) ij v t  is the speed update that will be used in determining the best position update (t 1) ij x  . then there are constants used in the formulation such as 𝑤 = inertia weight, and c is the velocity coefficient for pso and r are random numbers between -1 to 1. results and discussion results of surface deformation inversion data on sinabung volcano using mogi models with pso schemes showed good results in misfit and model responses so that it was sufficient to reconstruct the physical field model realistically. table 2. result of parameters model using pso phase model misfit aic a(m) delta p/g d(m) x(m) y(m) delta v 1 mogi dengan pso 0.0297 10.0593 669.5714 0.0626 27826.6160 450000.00 346001.89 58968083.71 2 mogi dengan pso 0.0564 10.8718 236.1255 0.0230 1300.0000 428500.00 348148.75 952446.95 1 1 2 2 ( 1) ( ) c ( ( )) (p x (t)) ij ij ij ij g ij v t wv t r p x t c r      ( 1) ( ) ( 1) ij ij ij x t x t v t    78 computational and experimental research in materials and renewable energy (cerimre) volume3, issue2, page 75-81 eissn : 2747-173x submitted : august 21, 2020 accepted : october 11, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23549 figure 2. inversion result in period 1. the inversion results in period 1 showed inversion result at depth of around 27.8 km with change in the volume around 36 1096.58 m . this result is possible that the source of the inversion pressure is not a local pressure source from sinabung volcano but another pressure source which can be a tectonic or partial melting source which requires further study. in period 1 sinabung volcano was classified in a normal active period where no eruptions occurred and the status of the sinabung volcano was downgraded after eruptions his first eruption from 27 august 2010 to 3 september 2010 [9], that condition also reinforces that the deformation of the surface of sinabung volcano in period 1 is not from the local source. 79 computational and experimental research in materials and renewable energy (cerimre) volume3, issue2, page 75-81 eissn : 2747-173x submitted : august 21, 2020 accepted : october 11, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23549 figure 3. inversion result in period 2. the inversion results in period 2 show the smallest misfit obtained from the inversion in the mogi model with the pso scheme. the source of the inversion pressure is at a depth of ±1.3 km with volume change around 6 3 0.95 10 m  in the northeast sector of sinabung volcano. with a fairly shallow in depth of the pressure source in period 2, it can conclude that the source is magma pocket of sinabung volcano. the inversion results are selected based on data misfit in accordance with the results of tectonic seismic hypocenter relocation by indrastuti (2017) shown in figure 4. based on the inversion of the pressure source elaborated by the relocation of tectonic volcanic activity, it is known that tectonic volcano is associated with magma pocket of sinabung volcano, from the model also known that there are magma supply from deep magma pocket to moderate magma pocket and shallow magma pocket which marked by seismic hypocenters while at the same time strengthening that the inversion results are in accordance with the conditions of sinabung volcano. 80 computational and experimental research in materials and renewable energy (cerimre) volume3, issue2, page 75-81 eissn : 2747-173x submitted : august 21, 2020 accepted : october 11, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23549 figure 4. hypocenter relocation of volcano tectonic [10] conclusions the model resulting from the inversion process is sufficient to reconstruct the physical field. from the inversion concluded that the position pressure source showing shallow magma pockets at a depth between ±1.3 km volume changes around 6 3 0.95 10 m  . it indicates the presence of a huge magma supply and continuous into shallow magma chamber up to the surface of sinabung volcano. references [1] pusat vulkanologi dan mitigasi bencana (pvmbg), 2010, data dasar gunung api di indonesia pusat vulkanologi dan mitigasi bencana (pvmbg) [2] n. haerani, a. basuki, y. suparman, s. primulyana, o. prambada, a. loeqman, and t. ohkura, 2012, evaluation of volcanic activity at sinabung volcano, after more than 400 years of quiet, journal of disaster research, 7(1), 37. [3] r. kumalasari, w. srigutomo, m. djamal, i. meilano, and h. gunawan, 2018, location of sinabung volcano magma chamber on 2013 using lavenberg-marquardt inversion scheme, journal of physics: conference series, 1013(1). [4] r. kumalasari, w. srigutomo, m. djamal, i. meilano, m. evita, and h. gunawan, 2019, location of sinabung volcano magma chamber on 2013 using simulated annealing inversion scheme. journal of physics: conference series, 1321(3). [5] k. mogi, 1958, relations between the eruptions of various volcanoes and the deformations of the ground surface around them, earthquake res. inst. univ. tokyo, volume 36, page 99-134 81 computational and experimental research in materials and renewable energy (cerimre) volume3, issue2, page 75-81 eissn : 2747-173x submitted : august 21, 2020 accepted : october 11, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23549 [6] d. dzurisin, 2007, volcano deformation: new geodetic monitoring technique, springer, berlin, heidelberg. [7] j. l. f. martínez, e. gonzalo, j. p. f. álvarez, h. a. kuzma, c. o. m. pérez, 2010, pso: a powerful algorithm to solve geophysical inverse problems application to a 1d-dc resistivity case, journal of applied geophysics, february 2010, pages 13–25. [8] h. gunawan, a. budianto, o. prambada, w. mccausland, j. pallister, and m. iguchi, 2017, overview of the eruptions of sinabung eruption, 2010 and 2013–present and details of the 2013 phreatomagmatic phase, journal of volcanology and geothermal research, volume 382, pages 103-119. [9] j. zhou, x. yu and b. jin, 2018, short-term wind power forecasting: a new hybrid model combined extreme-point symmetric mode decomposition, extreme learning machine and particle swarm optimization, sustainability (switzerland), 10(9). [10] n. indrastuti, a. d. nugraha, h. gunawan, w. mccausland, 2017, 3-d seismic tomographic study of sinabung volcano, northern sumatra, indonesia, during the intereruptive period october 2010 july 2013, journal of volcanology and geothermal research, volume 382, pages 197-209. https://www.sciencedirect.com/science/journal/03770273/382/supp/c https://www.sciencedirect.com/science/journal/03770273/382/supp/c 53 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 53-57 eissn : 2747-173x submitted : august 22, 2020 accepted : october 15, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23545 analysis curie temperature and hysteresis la0.7sr0.3mno3 with micromagnetic simulation muhamad rony febiantoro 1 , lutfi rohman 1,a and sutisna 1 1 physics department faculty of mathematical and natural sciences, jember, indonesia a el_rahman.fmipa@unej.ac.id abstract. simulation reseach has been carried out to obtain the characteristic of material la0,7sr0,3mno3. the simulation method used atomistic of magnetic materials. simulations were carried out using vampire software micromagnetic simulation were determine curie temperature and hysterisis curve. the monte carlo algorithm was used in this reseach. simulation were carried out by variation nanocube size 22 nm, 27 nm, and 32 nm. the simulation result show, curie temperature show in 27 nm have the biggest value and stuck in that value. the characteristics of the hysterisis curve 32 nm bigger than the others.from the simulation, it is found that the between the temperature and hysteris curve. more temperature value, the smaller the hysterisis curve. keywords: lsmo, curie temperature, micromagnetic simulation, hysteristic curve introduction currently, the development of technology results in higher human needs for data storage. all data storage and retrieval is done using the device. such as laptops, computers and cell phones. this activity is stored in a storage device. hard disk drive (hdd) is a digital data storage device that uses a disk (disk) coated with magnetic material [1]. hdd with strong power and heat resistance provides good magnetic characteristics at high temperatures. the approach that can be proposed in this case is to make a magnetic recording medium in the form of patterned media. the magnetic material is formed in a very small size so as to increase the bit density of the magnetic recording medium [2]. cmr materials can be a solution with larger data storage capacities and low power usage [3]. cmr materials such as la0,7sr0,3mno3 [lsmo] are predicted to have half-metal properties with high critical temperatures. the research on la0,7sr0,3mno3 was carried out by means of a micromagnetic simulation. this research was conducted to investigate its magnetic properties. parameter determination is done by looking for references and adjusting the software used. determining the sides of the cube is done by finding the critical diameter value and adjusting it. determination of the critical diameter is carried out to show changes in the properties of the domain. the critical diameter was found to be about 27 nm. the method used in this research is monte carlo. this method is used because the application is easier for data retrieval. theoretical background magnetic materials are materials that have magnetic properties. magnetic property is the ability of a material to attract or repel other materials around it. examples of magnetic materials are iron, steel, nickel, cobalt and their alloys [4]. a material magnetic have magnetic moment in the same direction. metals that are non-magnetic can be seen whose magnetic moments have an irregular direction so that the effects cancel each other out which results in no magnetic poles at the ends of the metal. 54 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 53-57 eissn : 2747-173x submitted : august 22, 2020 accepted : october 15, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23545 kittle describes the critical diameter of a single domain by comparing the energy required to make the domain wall against the reduction in magnetostatic energy or demagnetostatic energy during the creation or manufacture of the domain structure [5]. the critical diameter equation is given: √ (1) (2) with , √ is exchange length and is permeability of the material. this study uses micromagnetic simulation software, namely vampire. vampire 4.0 is an atomistic model simulation application for nanometer-sized magnetic materials [6]. this study uses a vampire to simulate the curie temperature and hysteresis curve which will be analyzed to determine the characteristics of the magnetic material. materials and methods this reseach was using vampire software with lsmo nanocube form to determine its magnetic properties. in this study, the relationship between magnetization and temperature was analyzed, the relationship between susceptibility and temperature at various material sizes of 22 nm, 27 nm and 32 nm. the size 27 nm is used because it is the result of a critical diameter calculation. meanwhile, other measurements are above the critical material size and below the critical diameter. the analysis results will provide information about magnetic properties such as magnetic sensitivity, curie temperature and hysteresis curves in ferromagnetic with various side sizes of the cube. the simulation produces the output that is processed using origin and povray. this research uses micromagnetic simulation, by creating input script files and material script files (table 1). table 1. source of micromagnetic simulation data parameter value crystal structure atomic spin moment ( 𝑆) simple cube 3.6 𝐵 anisotropy energy (ku) -3.38 x 10 -25 j/link unit cell lattice vector (a) 3.9 a exchange energy anisotropy constant (ku) hard axis coordinat number (z) spin number (s) spin wafe correction ( 3.45 x 10 -21 j/k -0.3 x 10 3 j/m 3 1,1,0 6 ⁄ 0.751 determination of curie temperature. the lsmo simulation results produced an output file which was then taken to a graph plot using origin software. the method is carried out combining a graph of the relationship between magnetic susceptibility and temperature based on the lsmo material. from this magnetic susceptibility graph, a more specific curie temperature can be determined by combining temperature to magnetization and susceptibility temperatures. the way to determine the curie temperature (tc) via a graph is to examine the 55 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 53-57 eissn : 2747-173x submitted : august 22, 2020 accepted : october 15, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23545 point between the temperature curve against magnetization and the temperature curve for susceptibility. when this point is close to zero on the magnetization axis, and the highest magnetic susceptibility value at that point can be said to be the curie temperature point of the ferromagnetic material. furthermore, it can be seen the effect of the side size of the cube material on the respective magnetic properties. determination of hysterisis curve. hysteresis curve determination. the hysteresis curve simulation results were analyzed using origin software. the analysis is carried out by making a graph of the magnetic relationship with the magnetic field. hysteresis curve analysis is carried out to see the properties or values of the saturation field and the coercivity field formed from the lsmo material based on its temperature. hysteresis curve analysis was performed using temperature variations on each side of the cube, namely the size of 0k, 100k, 200k, 300k and 400k. determination of the temperature was carried out using reference studies which showed that the material had a curie temperature of about 350k. take values above and below the curie temperature. the hysteresis curve shape can show the characteristics of the ferromagnetic material itself. furthermore, the material spin domain direction was visualized using povray software. results and discussion the results of the simulation produce the curie temperature (a) (b) (c) figure 1. magnetic magnetization and susceptibility graph against temperature in lsmo material (a) size 22 nm, (b) size 27 nm, (c) size 32 nm. table 1. curie temperature values in material lsmo size cubed (nm) curie temperature (k) 22 335 27 345 32 345 in ferromagnetic materials the spin is oriented in one direction without any external fields. this situation occurs only when the temperature does not exceed the transition temperature. figure 1 shown, when the temperature is above the transition temperature, the spin orientation of the material becomes random and causes its state to change to a paramagnetic material. the simulation results show that the curie temperature value does not change when the size of the material lsmo 27 nm in the form of nancube. table 1 shown the curie temperature value does not increase when it is above the critical side size. determination of the size of the critical side makes the material usable as efficiently as possible. a material larger than the critical size will 56 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 53-57 eissn : 2747-173x submitted : august 22, 2020 accepted : october 15, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23545 produce the same temperature value [7]. this occurs because the value of 27 nm is thought to have reached the critical side size of the material cube lsmo. lsmo material has a curie temperature value which has reached the highest value when the material size is 27 nm. (a) (b) (c) figure 2. lsmo hysterical curve against temperature variation (a) size 22 nm, (b) size 27 nm, (c) size 32 nm. (a) (b) (c) figure 3. lsmo hysterical curve temperature 400 k (a) size 22 nm, (b) size 27 nm, (c) size 32 nm. table 2. the coercivity and saturation field values of the lsmo material temperature variations size cubed (nm) coercivity field (tesla) saturation field (tesla) 0k 100k 200k 300k 400k 0k 100k 200k 300k 400k 22 1.05 0.55 0.35 0.2 1.5 0.8 0.6 0.4 27 1.05 0.6 0.35 0.2 1.5 0.9 0.6 0.4 32 1.2 0.7 0.45 0.2 1.5 0.9 0.7 0.4 the coercivity field value of the lsmo material at a size of 22 nm shows a value that decreases as the temperature increases. the saturation field value and the coercivity field also show the 57 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 53-57 eissn : 2747-173x submitted : august 22, 2020 accepted : october 15, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23545 value that decreases as the temperature increases. this also occurs in the coercivity and saturation fields at the sizes 22 nm, 27 nm and 32 nm. the hysteresis curve of the lsmo material, the saturation field value and the coercivity field, increased the greater the size of the material. however, the hysteresis curve will narrow as the temperature rises. this causes the coercivity field and saturation field values to decrease as the temperature increases, but the coercivity and saturation field values increase as the size increases. the change in the value of the magnetization occurs due to the influence of the external field given by the ferromagnetic material. conclusions the effect of cube side size variations on the lsmo material based on the simulation results, the cube side size variations affect the curie temperature value. at a size of 22 nm in the lsmo material, the curie temperature value is 335k, and for the 27 nm and 32 nm sizes the curie temperature value is 345k. at 27 nm the curie temperature value has reached the highest curie temperature value, which is thought to have reached the critical size value. this makes the efficiency value of an lsmo nanocube form material of 27 nm. the characteristics of the hysteresis curve of the lsmo material based on the simulation results obtained changes in the value of the saturation field and coercivity field on the side size of the material cube and the variations given. in lsmo material, the highest coercivity and saturation field values were found on the side size of the cube 32 nm. this value can be used as information on the characteristics of lsmo material references [1] r. chaudhary and a. kansal, 2015, a perspective on the future of the magnetic hard disk drive (hdd) technology, international journal of technical research and applications 3 (3): page 63-74. [2] alvarez, g. s, 2008, cubic versus spherical magnetic nanoparticles: the role of surface anisotropy, j. am. chem. socs 130. [3] l.rohman, d. djuhana, b. soegijono, and w. nursiyanto, 2013, dynamics micromagnetic simulation of la0. 7sr0. 3mno3 (lsmo) disk array patterned ferromagnetic, international journal of basic & applied sciences ijbas–ijens 13 (03), page 17-20. [4] w. d. callister jr, and d. g. rethwisch, 2012, fundamentals of materials science and engineering: an integrated approach, john wiley & sons. [5] a. t. widodo, 2013, studi mikromagnetik dinamika struktur domain pada material feromagnetik py, ni, fe dan co model nanosphere: micromagnetic study of dynamic domain structure in ferromagnetic py, ni, fe and co nanospheres model. [6] r. f. evans, w. j. fan, p. chureemart, t. a. ostler, m. o. ellis and r. w. chantrell, 2014, atomistic spin model simulations of magnetic nanomaterials, journal of physics: condensed matter 26 (10): 103202. [7] a. e. wahyuningsih, 2018, analisis temperatur curie dan kurva histerisis material alloy co(1-x)pt(x) model nanocube dengan simulasi mikromagnetik, skripsi, jember. universitas negeri jember. 7 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 7-11 submitted : august 28, 2018 accepted : october 2, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19543 characterization of carbon derived from water hyacinth as a renewable energy sources rani kusumaningtyas 1 , wenny maulina 1,a , supriyadi 1 1 department of physics, faculty of mathematics and natural sciences, university of jember, jember, jalan kalimantan no 37 jember 68121, indonesia a wenny@unej.ac.id abstract. an alternative renewable energy sources, such as biomass, can be produced using the combustion process inside the furnace. in this work, carbon derived from water hyacinth be produced through carbonization process. the carbonization of water hyacinth was carried out at different temperature i.e. 400°c, 500°c and 600°c and subsequently analyzed with the sem-edx to determine the microstructure and atomic percentage of present elements. while the ftir analysis was conducted to qualitatively verify the surface functional groups of carbon. the results of sem-edx analysis showed that the pores began to form at a carbonization temperature of 600°c and carbon content increased with increased temperature of carbonization process. ftir analysis results showed that the functional groups in the carbon derived from water hyacinth had an absorption pattern with oh, c-h, c-o, and c=c bonds. keywords: renewable energy sources, water hyacinth, sem-edx, ftir introduction improvement of economic activity causes an increase in world energy demand. the use of renewable energy is increasingly needed to substitute energy from fossil fuels. the projected global energy demand in 2040 will be supplied by 74% from fossil fuels and 26% from renewable materials, while the contribution of bioenergy from agricultural waste biomass will be 10.4% [1]. the advantage of using energy from biomass sources are produces environmentally friendly co2 emissions (zero carbon footprint) and can be regenerated by plants again, so it doesn't cause increase emission of greenhouse gases [2]. thus, renewable biomass plays a significant role in the energy supply in the world, especially in indonesia. indonesia is a country that has abundant biodiversity so that it can potentially be exploited. one of the most common biodiversity found in water areas is water hyacinth (eichhornia crassipes). water hyacinth is considered a highly invasive aquatic weed, infecting dam, lakes and irrigation channels. one major problem associated with water hyacinth is its rapid growth rate. it can easily adapt and compete with other aquatic plants causing a major threat to the aquatic environment. when not managed and controlled, these plants will cause blockage in bodies of water. although water hyacinth is seen as a weed and is responsible for many environmental and health problems, much research has been done in order to find useful applications for these plant [3]. one of the application which is can be used as a biomass sources. the renewable biomass generally includes three main components: cellulose, hemicellulose, and lignin; and cellulose and hemicellulose make up approximately 70% of the entire biomass [4]. water hyacinth can potentially be a resource due its high carbohydrate content (18% cellulose, 50% hemicellulose) [5]. charcoal is a type of black carbon produced from carbonization process when biomass is heated in a closed container with little or no available air [6,7]. the carbonization is a process in which non-carbon compounds are removed so that 8 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 7-11 submitted : august 28, 2018 accepted : october 2, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19543 organic cellulose can be decomposed into carbon. determination of the exact carbonization temperature determines the quality of the charcoal. here, different temperature in carbonization process are evaluated to clarify carbon derived from water hyacinth according to spectroscopy and microstructure analysis. material and methods the water hyacinth used in charcoal production was collected from one of the rivers in the province of lumajang in east java. the water hyacinth is taken part of the stem was washed to removed adhering dirt and then dried under the sun. once the sample dry, biomass cut into small pieces and was entered in the furnace, then the temperature of heating was set. the carbonization temperature is adjusted (according to variations at 400°c, 500°c, and 600°c) with a heating time of 1 hours each. after this carbonization process, sample crush until smooth at size of 200 mesh. based on the treatment of temperature at carbonization process, the following samples were obtained in this study: sample a1: water hyacinth charcoal at a carbonization temperature of 400°c sample a2: water hyacinth charcoal at a carbonization temperature of 500°c sample a3: water hyacinth charcoal at a carbonization temperature of 600°c furthermore, sample was characterized using scanning electron microscopy-energy dispersive x-ray (sem-edx) and fourier transform infrared (ftir). sem-edx to determine the microstructure and atomic percentage of present elements in the sample. while the ftir analysis was conducted to qualitatively verify the surface functional groups of carbon. results and discussion characterization of sem-edx sem was used to identify the surface morphology of carbon derived from water hyacinth. the surface morphology of carbon derived from water hyacinth with variations in carbonization temperature of 400°c, 500°c, and 600°c, can be seen in figure 1. sample a1 and a2 with carbonization temperature are 400°c and 500°c, respectively, shown nonporous structure of carbon. while sample a3 at carbonization temperature 600°c shown porous structure of carbon with diameter of pore in the amount of 0.572 µm. carbonization causes the components of the material to degrade to produce gases (co, co2, hydrogen and methane), liquid products (tar, hydrocarbons, water) and solid products, namely charcoal. the formation of pores at high temperatures were due to the evaporation of volatile matter from the materials at the carbonization process. the carbonization process causes the breakdown of carbon chains and will be more optimal with an increase in temperature [8]. in this study, characterization of edx aims to determine the atomic percentage of present elements in carbon derived from water hyacinth. table 1 shown the elements content of carbon derived from water hyacinth with various temperature. the edx results shown the percentage of carbon elements present in all the sample is above 80%. the percentage of carbon elements in sample a1, a2, and a3 were 82.70%, 87.76%, and 89.37%, respectively. it can be seen that the higher of the carbonization temperature causes the greater of the carbon content. this result accordance with the carbonization process which is explain that at temperatures of 310°c 510°c there is an increase in the amount of co, ch4, and h2 and tar whereas a decrease in the 9 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 7-11 submitted : august 28, 2018 accepted : october 2, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19543 amount of pyrolignic acid and co2. meanwhile at a carbonization temperature of 500°c 1000°c there is an increase in carbon content [9]. (a) (b) (c) figure 1. the surface morphology of carbon derived from water hyacinth at carbonization temperature (a) 400°c (sample a1), (b) 500°c (sample a2), and (c) 600°c (sample a3), respectively table 1. the elements content of carbon derived from water hyacinth at various temperature element wt% a1 a2 a3 c 82.70 87.76 89.37 o 14.47 7.10 7.58 na mg 0.41 0.31 0.81 al 0.16 si 0.37 s 0.14 cl 0.47 2.25 0.99 k 0.48 2.09 0.97 ca 0.50 0.50 0.28 zr 0.29 10 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 7-11 submitted : august 28, 2018 accepted : october 2, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19543 characterization of ftir figure 2. ftir spectra of carbon derived from water hyacinth at carbonization temperature 400°c (sample a1), 500°c (sample a2), and 600°c (sample a3) figure 2 shown the surface functional groups of carbon derived from water hyacinth at a various carbonization temperature. the spectral pattern of the ftir results in sample a1 shows that there is a vibration of hydroxyl groups (o-h stretching) at the wavenumber 3324 cm -1 . the asymmetric c-h stretching at the wavenumber 2925 cm -1 . the band at around 1605 cm -1 indicates a c=c stretching vibration of aromatic compounds. the asymmetric c-h bending vibration mode of hydrocarbon aliphatic bond at the wavelength of 1414 cm -1 . whereas, a symmetric c-h bending group at the wavenumber of 1316 cm -1 . c-o stretching vibration observed at around 1076 cm -1 . a weak band at the wavenumber 873 cm -1 was describe to c-c stretching vibration. from this results shown that carbon derived from water hyacinth at carbonization temperature of 400°c has a little amount of carbon elements. in a sample a2 with carbonization temperature of 500°c, the band at around 3324 cm -1 could be ascribed to hydroxyl groups (o-h stretching). band observed appearing at around 1585 cm -1 for aromatic compounds (c=c stretching). the vibration of the asymmetric c-h bending at the wavenumber 1409 cm -1 . c-o stretching vibration observed at around 1069 cm -1 .the band at wavenumber 875 cm -1 for c-c stretching vibration. the peak of the absorption band in ftir spectra sample a2 was lower than sample a1. this occurs because at a temperature of 500°c the absorbance decreases of aromatic compounds and increases in the carbon element which is formed based on the increase in the absorbance value of the c-c stretching vibration group. the functional group in sample a3 looks alike in sample a2. vibration group of o-h stretching, c=c stretching, asymmetric c-h bending, c-o stretching, and c-c stretching were observed at a wavenumber 3338 cm -1 , 1571 cm -1 , 1413 cm -1 , 1039 cm -1 , and 875 cm -1 , respectively. spectroscopy analyzed of carbon derived from water hyacinth at a various carbonization temperature shown that the carbonization process with higher temperatures will result in 11 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 7-11 submitted : august 28, 2018 accepted : october 2, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19543 changed in functional groups, shifted in wavenumbers, reduced absorption rates and formed a new compounds. conclusions sem patterns reveal the porous structure of carbon derived from water hyacinth occurs at carbonization temperature 600. while, temperature 400 and 500 not reveal the porous materials. the carbonization process of water hyacinth at various temperature (400, 500, and 600) indicates that an increase in carbonization temperature causes an increase in the percentage of carbon elements. the resulting sequences were 82.70%, 87.43%, and 89.37%. the ftir peaks shown oh, c-h, c-o, and c=c bonds. the atomic groups and structure present are aromatic, aliphatic, tertiary and secondary hydroxyl structures. the presence of aliphatic and aromatic hydrocarbons in carbon means that it contains fats and oils that are related to butane or isobutene, making it easier to burn or heat up. likewise, the presence of hydroxyl groups means that there is an alcohol present which could contribute to higher flammability of substances. hence, water hyacinth is considered a suitable raw material as a renewable energy sources. references [1] international energy agency, world energy outlook 2018, executive summary, www.iea.org/weo/, accessed on 16 august 2019. [2] a kadiyala, r kommalapati and z huque, 2016, sustainability, volume 8, page 11811192. [3] n p carnaje, r b talagon, j p peralta, k shah and j paz-ferreiro, 2018, plos one, volume 13(11), page 1-14. [4] x shen, r r kommalapati and z huque, 2015, sustainability, volume 7, page 1297412987. [5] h a fileto-perez, j g rutiaga-quinones, c n aguilar-gonzales, j b paez, j lopez and o m rutiaga-quinones, 2013, bioresources, volume 8(4), page 5340-5348. [6] l m deem and s e crow, 2017, reference module in earth systems and environmental sciences, page 1-5. [7] o d nartey and b zhao, 2014, advances in materials science and engineering, page 112. [8] h nurdiansah and d susanti, 2013, jurnal teknik pomits, volume 2(1), page 23019271. [9] desi, a suharman and r vinsiah, 2015, prosiding semirata, page 294-303. http://www.iea.org/weo/ 17 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 17-23 submitted : september 15, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19545 comparative analytic of viscoelasticity carbon, glass, and graphite fiber composite using maxwell model ro’sil khohar 1,a , umi sa’adah 1 and dewi azzahra puspita 1 1 fisika, fakultas matematika dan ilmu pengetahuan alam universitas jember, indonesia a rosilqohhar46@gmail.com abstract. the fulfillment of the need for materials with viscoelastic characteristics to be a supporting factor. the aim is to obtain composite materials with good viscoelasticity. vinylester matrix composite materials with variations of graphite, glass, and carbon fibers were tested using fea and maxwell model. the simulated viscoelasticity of the isotropic, transverse, and mixed state of glass, carbon, and graphite fibers depends on the magnitude of modulus young and poisson's ratio. the most significant sequence value of viscoelasticity is in graphite fiber 10.4 gpa, carbon 5.5 gpa fiber, and glass fiber 3.78 gpa. keywords: viscoelastic, fea method, maxwell model introduction currently, the development of materials technology is growing rapidly. fulfilling the need for materials with specific composite characteristics is also a driving factor. various kinds of materials have been used, and further research is also being done to get the functional materials, one of which is polymer composite materials. its ability to be easily shaped as needed, both in terms of strength and other advantages, encourages the use of polymer composite materials as alternative materials or substitutes for conventional metal materials in various products produced by industries, especially the manufacturing industry [1]. composite materials are materials that are composed of a combination of two or more primary elements that differ in the macro form or composition of materials, which are inseparable [2]. the advantages of composite materials compared to the metals are corrosion resistance or resistance to the influence of the free environment. for certain types of composites, it has better strength and stiffness. therefore, continuous research is directly proportional to the technology development of these materials, especially composites. the development of composites is not only from synthetic composites but also from renewable natural composites, thereby reducing the environmental pollution. research on composite materials and components made of composite materials has been widely carried out. several studies discuss the characteristics of composite materials based on their viscoelastic. however, none of these studies have compared the characteristics of composites that are reinforced with graphite fibers, glass fibers, and carbon fibers. this argument encourages researchers to conduct further research. in this study, the characteristics of the composite that want to be known are the stiffness, strength, and density of the composite reinforced with glass fiber, graphite fiber, and carbon fiber. this statement causes researchers to want to obtain composite materials that are strong, stiff, durable, and also lightweight. so, we must be able to determine the characteristics of the appropriate polymer composites, namely the tensile test and density test. from the background 18 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 17-23 submitted : september 15, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19545 above, the problem raised in this journal is how the characteristics and comparison of fiberreinforced composite materials from three materials in the form of glass fiber, graphite fiber, and carbon fiber using the maxwell model. the objective of this research is that the researcher wants to know and characterize the composite material reinforced with glass fiber, graphite fiber, and carbon fiber as an alternative to industrial raw materials. the benefits of this research can be used in the maxwell modeling field and also carried out to determine the characteristics of the effect of variations in the elasticity fraction of the three types of composites. the modeling knows the comparison of the characteristics of the composite structure with each other, understands the composites with characteristics that are close to ideal and also know which composites can be used as alternative materials, the industrial raw material on graphite, glass, and carbon fibers. a composite material is a material consisting of two or more different materials that are combined or mixed macroscopically into a useful material [3]. the composite materials are combined materials. in macro terms, the composite material can be defined as a material system composed of a mixture/combination of two or more different main elements. the composition of this composite constituent material can no longer be separated [6]. composites produced by an agency or factory can usually predict the mechanical properties of the composite materials based on the matrix and reinforcing materials [4]. viscoelastic is a property of a material to test strain, stress, and strength in a material. the response of each material to a given external load depends on the properties of the material. materials whose behavior is influenced by a function of time are called viscoelastic materials. equations can explain the time-dependent behavior of viscoelastic materials with variables of stress, change in shape, and time. the magnitude of the tensile strength produced by polymer/fiber composites can be predicted using equation 2.1. based on this equation, it can be used by researchers to determine the extent of the tensile strength produced by the composite based on the fundamental matrix and reinforcement. here is the viscoelasticity equation: (1) graphite is the carbon atoms connecting each other into sheets, and graphite is the most stable form of carbon. graphite is soft but very strong. it is resistant to heat and, at the same time, a conductor of heat. found in metamorphic rocks, it appears as a metallic but opaque substance with a color that varies from dark gray to black. glass fibers have different characteristics from one another. in its use, glass fibers are adjusted according to their properties or characteristics. glass fibers are made of silica, alumina, lime, magnesia, and others. the advantage of glass fiber lies in the ratio (comparison) of price and performance, namely low production costs, very simple production processes. glass fibers are widely used in the automotive industries such as in-vehicle body panels. even motorbikes are now all body made of glass fiber reinforced composites. glass-epoxy and glass-polyester composites are also applied to ship hulls and aircraft parts. 19 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 17-23 submitted : september 15, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19545 carbon fiber serves as a reinforcing material in carbon fiber composites. as for the matrix, polymer resins such as epoxy are usually used. this resin matrix serves to bind the reinforcing elements. because carbon fiber is only composed of these two materials, the properties of carbon fiber are also solely determined by these two materials. both being very light and strong is one of the advantages of carbon fiber composites. method this study aims to determine the viscoelasticity ratio of graphite, glass, and carbon fibers. finite element analysis (fea) is carried out in several stages as follows. first, idealization, which is changing physical problems into a model. in modeling, there will be idealization or simplification because the physical problems that do occur are often very complex. also, idealization and simplification occur in defining boundary conditions such as working load and the amount of displacement on support. shipments that do not change significantly with time are usually idealized as static loads. the load can also be modeled in the form of concentrated load, distributed load, or both combined. the support can also be modeled as a support die, hinge, or roller. maxwell model is used for a creep test at the end of the model with constant stress, as shown in figure 1. figure 1. maxwell model the laplace transform is used to derive relaxation from maxwell's model, table 1. laplace transform function f(t) = l -1 {f(s)} f(t) = l {f(s)} constant a a/s linier at a/s 2 derivative df/dt sf(s)-f(0) exponential exp(at) 1/(s-a) convolution integral ∫ ( ) ( ) * + * + then with the inverse laplace transform, relaxation is obtained in the time domain: (2) 20 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 17-23 submitted : september 15, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19545 where t = τ (material time constant) the research flowchart of this journal can be seen in figure 2. figure 2. the research flowchart boundary conditions and parameters the following are the boundary conditions and parameters used in the simulation process. 1. characteristics of vinylester young's modulus (ef 3,78 gpa) poisson's ratio (nu_f 0.35) density (1160 kg / m3) 2. characteristics of graphite young's modulus (ef 45 gpa) poisson's ratio (nu_f 0,3) density (641 kg/m 3 ) 3. karakteristik kaca young's modulus (ef 45 gpa) poisson’s ratio (nu_f 0,3) density (2000 kg/m 3 ) 4. karakteristik karbon young's modulus (ef 133,86 gpa) 21 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 17-23 submitted : september 15, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19545 poisson’s ratio (nu_f 0,3) density (1520 kg/m 3 ) results and discussion a load that has high stiffness when it is subjected to load (within its elastic limit) will experience elastic deformation but only slightly. the modulus of elasticity usually indicates the stiffness of a material. the higher the modulus of elasticity of the composite, the stiffer the composite material will be. in this study, a graph of the value of elasticity and viscoelasticity was obtained for each fiber. graph of the elasticity and viscoelasticity of the transverse modulus of graphite fibrous composites can be seen in figure 3. figure 3. graph of the elasticity and viscoelasticity of the transverse modulus e2 of graphite fibrous composites based on the figure, it can be seen that the elasticity of the graphite fiber is in the range of 1015 gpa, which is about 10.4 gpa. meanwhile, the viscoelasticity response to time for graphite fibers is decreasing. the glass fiber material is one type of composite fiber that has the advantage of being strong but still light. in fiberglass composites, the reinforcing component is glass fibers. the glass that we know every day has properties that are easily cracked and broken, this is since the hardness of the glass surface is too high, making it easier for the crack propagation process on the glass surface even with a slight defect or load. to avoid initial cracks or defects on the glass surface, the glass is made of very thin threads with a diameter of about 5-25 micrometers. the graph of the elasticity and viscoelasticity of the transverse modulus of glass-fibrous composites can be seen in figure 4. 22 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 17-23 submitted : september 15, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19545 figure 4. the elasticity and viscoelasticity values of the transverse modulus e2 of glass-fibrous composites based on the figure, it can be seen that the elasticity of the glass is between 5-10 gpa or about 3.78 gpa. meanwhile, the viscoelasticity response of glass fibers to time changes is decreasing. carbon fiber is a form of composite material. composite materials are composed of two main components, namely the matrix and the reinforcing material. carbon fiber serves as a reinforcing material, while the matrix is usually used polymer resins such as epoxy. several factors influence the properties of carbon fiber. one of the most important factors is the direction or groove of the carbon fiber. the graph of the elasticity and viscoelasticity of the transverse modulus of carbon fiber composites can be seen in figure 5. figure 5. graph of the elasticity and viscoelasticity of the transverse modulus of carbon fiber composites 23 computational and experimental research in materials and renewable energy (cerimre) volume 1, issue 1, page 17-23 submitted : september 15, 2018 accepted : october 20, 2018 online : november 10, 2018 doi : 10.19184/cerimre.v1i1.19545 based on this figure, it can be seen that the elasticity of carbon fibers is almost the same as the elasticity of glass fibers, which is about 5.5 gpa. however, the viscoelasticity response to time for carbon fibers is lower than for glass fibers. based on the graph of the three graphite, glass, and carbon fibers, it can be seen that the elasticity of the material remains constant. in contrast, the viscoelasticity of the material decreases. carbon fiber has the lowest viscoelasticity response value compared to graphite and glass fibers. the viscoelasticity value does not depend on the size of the object but only depends on the type of object. conclusions the viscoelasticity that has been simulated in isotropic, transverse, and mixed states of glass fiber, carbon, and graphite depends on the size of young's modulus and poisson's ratio. the value of the order of the greatest viscoelasticity is in graphite fiber, carbon fiber, and glass fiber. references [1] d a porwanto, and l johar, 2003, karakterisasi komposit berpenguat serat bambu dan serat gelas sebagai alternatif bahan baku industri, surabaya, its. [2] m m schwartz, 1984, composite material handbook, new york: mcgraw hill inc. [3] j w d callister, 2007, an introduction material science and engineering, united states of america quebecor versailles. [4] p m jones, 1975, mechanics of composite materials institute of technology, southern methodist university, mc. graw-hill, dallas. [5] e j barbero, 2014, finite element analysis of composite materials using ansys, crs press, taylor & francis group. 1 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 1-7 eissn : 2747-173x submitted : march 5, 2021 accepted : april 21, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24961 study of the structure and electronic properties of the zno monolayer: density functional theory muhammad fadlan raihan 1,a , triati dewi kencana wungu 1,3,b and brian yuliarto 2,3 1 department of physics, faculty of mathematics and natural sciences, institut teknologi bandung, jl. ganesa no. 10 bandung 40132, indonesia 2 department of engineering physics, faculty of industrial technology, institut teknologi bandung, jl. ganesa no. 10 bandung 40132, indonesia 3 research center for nanosciences and nanotechnology, institut teknologi bandung, jl. ganesa no. 10 bandung 40132, indonesia a fraihan1710@gmail.com, b triati@fi.itb.ac.id abstract. zno has received considerable attention since it has promising applications in electronic devices. although many studies have explored the potential of zno as a promising material, the precise role of geometric in zno remains unclear. this study deals with the electronic structure of the zno monolayer using density functional theory (dft). the dft was used to investigate the band structure and density of states of the zno monolayer. it is observed that the structural change of zno from bulk to monolayer increases the bandgap by 1.84 ev without changes its natural characteristic. moreover, this study provides information about the properties of the zno monolayer and its potential in electronic and magnetic devices application. keywords: dft, monolayer zno, band-gap introduction semiconducting metal oxides have been extensively studied as functional materials for wide applications relating to sustainable development, such as energy conversion/storage [1], environmental remediation [2], and high-performance electronics [3]. based on simplicity in synthesis, nontoxicity, and relatively low-cost production, zno becomes one of the semiconducting metal oxides that have been used in many applied technologies [4]. due to the fact that zno has its uniques properties, huge demand in manufacturing zno provides new opportunities for tuning the nano and mesoscale structures of zno to extend its applications [5]. in recent years, zno nanostructures such as nanowires, nanobelts, and nanorings have been synthesized for electronic devices such as field-effect transistors [6], supercapacitors [7], and gas sensors [8]. moreover, several studies have also found that the zn atoms can induce ferromagnetic properties on thin films of zno nanowires without doping transition metal atoms, which commonly are harmful to humans. thus, zno semiconductor material can be used in the biomedical field due to it does not have harmful toxins [9]. the potential of zno as a promising material still needs to be explored to enhance its performance. one of the techniques that can be used is by modifying the morphology of zno into a monolayer structure. however, modifying the morphology in an actual experiment is 2 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 1-7 eissn : 2747-173x submitted : march 5, 2021 accepted : april 21, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24961 unpredictable and requires many trials and errors. therefore, we need a simulation approach to predict the resulting morphology in the modification of zno. the morphological modification of various materials, especially zno, can be predicted using the density functional theory (dft) simulation method because the obtained calculations are close to the experimental results [10]. in this study, the zno monolayer will be simulated using dft to analyze the geometry and electronics properties of the material. computational details the monolayer structure of zno was obtained by cutting the bulk structure of zno at [0 0 1] orientation (figure 1). this treatment is consistent with the structure of the zno monolayer, which was experimentally synthesized by young and lai [11]. we constructed a periodic (4 x 4) supercell of zno monolayer with a 15 å vacuum space in all models to avoid interactions between adjacent layers. figure 1. bulk structure of zno; zn (yellow), and o (grey) [12] the electronic properties and geometrical structure of the zno monolayer were investigated by the density functional theory (dft) method. all calculations were performed using perdewburke-ernzerhof (pbe) exchange-correlation functional implemented in the vienna ab initio simulation package (vasp) [13]. for the plane-wave basis set, an energy cutoff of 490 ev was used. the maximal force of 0.01 ev/å was used as the convergence criterion for ionic relaxations, and 10 -5 was also used for convergence tolerances. the brillouin zone was sampled monkhorst-pack mesh [14] with 5×5×1 k-points in the geometry optimization and 20×20×1 k-points arranged in the electronic structure [14]. the fully relaxed geometry was performed to obtain the optimized structure. the electronic structure is analyzed by calculating the band structure and the density of state (dos). results and discussion after optimizing the geometry, the layer of zno monolayer changed from the initial structure with a rippled surface into a honeycomb-like structure similar to graphene (figure 2). interestingly, 3 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 1-7 eissn : 2747-173x submitted : march 5, 2021 accepted : april 21, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24961 the calculated zn-o bond length is 1.876 å which is shorter than the bulk structure [15]. this result is related to the fact that the atoms in the monolayer structure have a lower coordination number than the bulk structure. hence, the atoms in the zno monolayer strengthen the bonds between the zn-o atoms themselves and shorten the bond length. figure 2. monolayer structure of zno; (a) top view; (b) side view before optimization; (c) side view after optimization. to determine the electronic properties of the zno monolayer, it is necessary to calculate the band structure and density of state (dos) of the material; the result of the calculation can be seen in figures 3 and 4. figure 3. band structure and partial density of states (pdos) 4 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 1-7 eissn : 2747-173x submitted : march 5, 2021 accepted : april 21, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24961 the pdos in figure 3 shows that the high density in the conduction band is dominated by o -2p atoms while the valence band is dominated by zn-3d atoms, which similar to the bulk structure. this result indicates that the zn atom transfers its charge to the o atom, forming a zn-o bond with ionic interaction. figure 4. total density of states (tdos) as shown in figure 4, the electronic state densities are symmetrical for both spin-up and spindown. the symmetrical electron density causes the magnetic moment of this material to be zero, indicating that zno is a non-magnetic semiconductor material. table 1. the energy gap of zno materials with various nanostructures material structure gga zno wurtzite 0.75 ev [16] zincblende 0.65 ev [17] nanowire 0.71 ev [18] 0.91 ev [19] nanoribbon 1.76 ev [20] 1.30 ev [21] monolayer 1.84 ev (this study) in addition, the comparison of the generalized gradient approximation (gga) bandgap of zno semiconductors with various nanostructures is presented in table 1. the monolayer zno ha s a direct bandgap of 1.84 ev (figure 4). this result was higher compared to the other reported nanostructure. the fact also shows that the zno monolayer has a larger bandgap compared to nanowire and nanoribbon structures. the bandgap is the forbidden region to be occupied by electrons. a larger forbidden region signifies a greater restriction on the movement of electrons [22]. moreover, the large energy bandgap in the uv region and fast recombination rate of 5 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 1-7 eissn : 2747-173x submitted : march 5, 2021 accepted : april 21, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24961 electron-hole pairs retards its application as a photocatalyst under direct sunlight [23]. these results indicate that monolayer zno can be applied in nanoscale photoelectronic devices, especially for uv photon emitters and detectors. conclusions the structure and electronic properties of the zno monolayer have been investigated using density functional theory (dft) calculations. the calculation results show that the modification of the zno monolayer structure can provide an alternative to increasing the bandgap without changing the characteristics of zno as a semiconductor with a direct bandgap. these results indicate that monolayer zno can be applied in electronic devices such as uv photon emitters and detectors. the dos analysis also shows that the zno monolayer has a significant charge transfer from the zinc (zn) atom to the nearest oxygen (o) atom. acknowledgements the authors acknowledge the research center for nanosciences and nanotechnology (ppnn), institut teknologi bandung, indonesia, for providing technical support and calculation facilities. this study was supported by a grant from the national research and innovation agency indonesia (ristek-brin) 2021. references [1] h. wang et al., jun. 2015, bifunctional non-noble metal oxide nanoparticle electrocatalysts through lithium-induced conversion for overall water splitting, nat. commun, volume 6, no. 1, page 1–8. [2] z. zhang, j. liu, j. gu, l. su and l. cheng, jul. 18, 2014, an overview of metal oxide materials as electrocatalysts and supports for polymer electrolyte fuel cells, energy and environmental science, volume 7, no. 8, royal society of chemistry, page 2535–2558. [3] s. park, c. h. kim, w. j. lee, s. sung, and m. h. yoon, apr. 01, 2017, sol-gel metal oxide dielectrics for all-solution-processed electronics, materials science and engineering r: reports, volume 114. elsevier ltd, page 1–22. [4] n. a. abdullah, z. khusaimi, and m. rusop, 2013, a review on zinc oxide nanostructures: doping and gas sensing, in advanced materials research, volume 667, page 329–332. [5] s. y. wakhare and m. d. deshpande, oct. 2019, the electronic and optical properties of monovalent atom-doped zno monolayers: the density functional theory, bull. mater. sci., volume 42, no.5, page 206. [6] y. li et al., apr. 2017, enhanced performance in al-doped zno based transparent flexible transparent thin-film transistors due to oxygen vacancy in zno film with znal-o interfaces fabricated by atomic layer deposition, acs appl. mater. interfaces, volume 9, no. 13, page 11711–11720. [7] d. cai et al., sep. 2014, high-performance supercapacitor electrode based on the unique zno@co3o4 core/shell heterostructures on nickel foam, acs appl. mater. interfaces, volume 6, no. 18, page 15905–15912. [8] y.-f. sun et al., feb. 2012, metal oxide nanostructures and their gas sensing 6 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 1-7 eissn : 2747-173x submitted : march 5, 2021 accepted : april 21, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24961 properties: a review, sensors, volume12, no.3, page 2610–2631. [9] q. wang, q. sun, g. chen, y. kawazoe, and p. jena, may 2008, vacancy-induced magnetism in zno thin films and nanowires, phys. rev. b condens. matter mater. phys., volume 77, no. 20, page 205411. [10] c. szakacs, e. merschrod s., and k. poduska, may 2013, structural features that stabilize zno clusters: an electronic structure approach, computation, volume 1, no. 1, page 16–26. [11] s. j. young and l. t. lai, dec. 2015, field emission properties of zno nanosheets grown on a si substrate, microelectron. eng., volume 148, page 40–43. [12] m. a. borysiewicz, oct. 2019, zno as a functional material, a review, crystals, volume 9, no. 10, page 505. [13] g. kresse and j. furthmüller, oct. 1996, efficient iterative schemes for ab initio totalenergy calculations using a plane-wave basis set, phys. rev. b condens. matter mater. phys., volume 54, no. 16, page 11169–11186. [14] h. j. monkhorst and j. d. pack, jun. 1976, special points for brillouin-zone integrations, phys. rev. b, volume 13, no. 12, page 5188–5192. [15] d. q. fang, a. l. rosa, r. q. zhang, and t. frauenheim, apr. 2010, theoretical exploration of the structural, electronic, and magnetic properties of zno nanotubes with vacancies, antisites, and nitrogen substitutional defects, j. phys. chem. c, volume 114, no. 13, page 5760–5766. [16] m. usuda, n. hamada, t. kotani, and m. van schilfgaarde, sep. 2002, all-electron (formula presented) calculation based on the lapw method: application to wurtzite zno, phys. rev. b condens. matter mater. phys., volume 66, no. 12, page 1–8. [17] m. oshikiri and f. aryasetiawan, oct. 1999, band gaps and quasiparticle energy calculations on zno, zns, and znse in the zinc-blende structure by the gw approximation, phys. rev. b condens. matter mater. phys., volume 60, no. 15, page 10754–10757. [18] m. srivastava and a. srivastava, aug. 2019, electron transport in co2 adsorbed zno nanowire: dft study, chem. phys. lett., volume 729, page 17–23. [19] f. c. zhang, z. y. zhang, w. h. zhang, j. f. yan, and j. n. yong, jun. 2009, firstprinciples study of the electronic and optical properties of zno nanowires, chinese phys. b, volume 18, no. 6, page 2508–2513. [20] a. de sarkar and r. ahuja, nov. 2014, electronic charge transport through zno nanoribbons, j. phys. chem. solids, volume 75, no. 11, page 1223–1228. [21] p. singh, d. k. k. randhawa, tarun, b. c. choudhary, g. k. walia, and n. kaur, jan. 2020, first-principles investigation on armchair zinc oxide nanoribbons as uric acid sensors, j. mol. model, volume 26, no. 1, page 1–11. [22] a. samavati et al., jan. 2021, influence of zno nanostructure configuration on tailoring the optical bandgap: theory and experiment, mater. sci. eng. b solid-state mater. adv. technol., volume 263, page 114811. [23] m. s. nadeem, t. munawar, f. mukhtar, m. naveed ur rahman, m. riaz, and f. iqbal, 7 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 1-7 eissn : 2747-173x submitted : march 5, 2021 accepted : april 21, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24961 apr. 2021, enhancement in the photocatalytic and antimicrobial properties of zno nanoparticles by structural variations and energy bandgap tuning through fe and co codoping, ceram. int., volume 47, no. 8, page 11109–11121. 47 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 47-52 eissn : 2747-173x submitted : july 1, 2020 accepted : september 21, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23544 effect of tio2 addition on the electrical conductivity of nylon-tio2 hybrid membrane nurul octavia hijriyatur rohmah 1,a 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no. 37, jember 68121, indonesia a nurulokta531@gmail.com abstract. current membrane technology has developed rapidly in industrial commercial interests. this has led to various studies, especially on membrane raw material innovation. research on the measurement of electrical conductivity on nylon-tio2 hybrid membranes has been carried out. this study aims to determine the addition of the right tio2 mass fraction based on the electrical conductivity value. the variations in the concentration of tio2 used were 0.5%, 1%, 3%, 5%, and 7% (w/v). the nylon-tio2 hybrid membrane was prepared using the phase inversion method. the measurement of the electrical conductivity of the hybrid membrane was carried out using the parallel plate method. the measurement results of the nylon-tio2 hybrid membrane showed that the electrical conductivity of the hybrid membrane increased with the addition of the mass fraction of tio2, from (0.66 ± 0.04) × 10 -9 s / cm for nylon membrane to (9.15 ± 5.71) × 10 -9 s / cm for additionalmass fraction of tio2 5% (w/v). meanwhile, onadditionthe mass fraction of tio2 7% (w/v) causes the electrical conductivity of the hybrid membrane to decrease, by obtaining an electrical conductivity value of(2.31 ± 0.45) × 10 -9 s / cm keywords: hybrid membrane, nylon, tio2, electrical conductivity introduction in recent years membrane technology has developed rapidly, both on a laboratory scale and on a commercial scale. the synthesis and characterization of membranes continues to progress, especially in terms of making synthetic membranes which are expected to replace the function of natural membranes. synthetic membranes can be made from ceramic or polymer materials. ceramic membranes generally have chemical, physical, and thermal properties that are superior to polymer membranes. however, ceramic membranes are relatively expensive, brittle, and difficult to manufacture. meanwhile, polymer membranes are cheaper, flexible, easy to form, and are widely used in industry [1]. nylon is a polyamide compound, which is a type of polymer compound that has an amide group in each repeating unit [2]. in addition, nylon is a thermoplastic polymer that has flexible properties and can be recycled (recycling) so it is widely used in various applications. nylon is widely chosen as a polymer matrix and can be used as a membrane because it is cheap, has good mechanical and physical properties, which is stretchable up to 8%, is resistant to extreme ph, is resistant to high temperatures, is resistant to corrosion, and forms a homogeneous mixture when combined with suitable solvent [3-4]. one way to improve the performance of polymer membranes is to add inorganic materials to the membrane, which is commonly known as a mixed matrix membrane (mmm). hybrid membrane is a membrane made from a mixture of polymer and inorganic materials which aims to 48 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 47-52 eissn : 2747-173x submitted : july 1, 2020 accepted : september 21, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23544 overcome the weaknesses of each raw material [5]. tio2 is an inorganic material that can be mixed into polymer membranes. tio2 is widely used as a photo catalytic material because it is very stable, resistant to corrosion, non-toxic, and high resistance to bacteria, has a high refractive index [6-7]. in addition, tio2 has high oxidizing ability and can conduct electricity [8]. one of the characteristics of the membrane can be determined physically by measuring its electrical properties. measurement of the electrical properties of the membrane to observe the ion transport mechanism and as a fuel cell material has been widely used. research on the electrical properties of hybrid membranes using tio2 has been carried out. reported that the tio2 material added to the polysulfan polymer membrane caused the conductance and capacitance values conductance to increase, but the loss coefficient decreased [9]. research [10], also states that the cellulose acetate membrane with tio2 added causes the conductance to increase. the best electrical properties resulted from the addition of 5 wt% tio2 concentration. juliandri has successfully synthesized a fuel cell membrane from pvdf doped with tio2 [11]. the highest electrical conductivity was obtained at the addition of 3 wt% tio2 concentration. based on these studies, measurements of the electrical properties of several tio2-polymer hybrid membranes have been carried out before. however, there is still little information regarding the electrical properties of the nylon-type polymer added with tio2. this study is expected to provide information related to the addition of the right tio2 mass fraction to the nylon-tio2 hybrid membrane to obtain the best membrane results measured from its electrical properties. theoretical background the membrane is a thin layer that can act as a filter or barrier (barrier) that limits the two phases [12]. the first phase is known as the feed or feed solution, which is the component that is separated and the second phase is the permeate, which is the component of the separation. the ability of a membrane to pass a component or molecule is influenced by differences in physical and chemical properties between the membrane and the components [13]. one of the properties possessed by the membrane is electrical conductivity. conductivity arises due to the interaction between the ion and the membrane. electrical conductivity is a measure of a material's ability to conduct electric current. if there is an electric potential difference at the ends of the conductor, the charges will move to produce an electric current. the electrolyte membrane is influenced by two things, namely the concentration of ions as charge carriers and the mobility of these ions [14]. the conductivity (σ) is inversely proportional to the resistivity value ( ). the conductivity value of a material depends on the properties of the material. the equation for calculating electrical conductivity is: (1) where σ is electrical conductivity (s/cm), is electrical resistivity (ohm.cm), is polymer membrane resistance (ohm), is membrane thickness (cm), is the cross-sectional area of the 49 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 47-52 eissn : 2747-173x submitted : july 1, 2020 accepted : september 21, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23544 electrode (cm 2 ) [14]. electrical conductivity arises due to the interaction between ions and the membrane [15]. materials and methods a.) membrane synthesis the nylon-tio2 hybrid membrane was prepared using the phase-to-solid phase inversion method. the membrane in this study used a nylon mass of 6 grams. the mass variation of tio2 which was mixed was respectively 0.030 gram (0.5 wt%); 0.061 gram (1 wt%); 0.186 gram (3 wt%); 0.316 gram (5 wt%); and 0.450 grams (7 wt%). the membrane was made by mixing nylon thread and tio2 into 20 ml of 25% hcl and 2 ml of acetone. then stirred using a magnetic stirrer for ± 1 hour until the solution is homogeneous. the membrane was then printed on a glass plate and immersed for 10 minutes in distilled water to facilitate the removal of the membrane from the glass plate. the formed membrane was dried for ± 12 hours. b.) electrical conductivity test the electrical conductivity test was carried out at room temperature using a lutron 9183 lcr meter. measurements using a two-plate parallel system method. the chip plate parallel to the capacitor is made of pcb plates measuring 2.5 2.5 cm. then the membrane that has been cut is adjusted and placed between the pcb plates. the plate is then connected to the lcr meter tool to measure its resistance value. the electrical conductivity measurement scheme is shown in figure 2. for each variation, 3 test samples were taken as repetition. figure 1. electrical conductivity measurement scheme results and discussion the nylon-tio2 hybrid membrane is a membrane made of nylon polymer material added with the inorganic tio2 material. in this study, the addition of tio2 mass fraction into nylon polymer to obtain the best nylon-tio2 hybrid membrane based on electrical measurements. membrane manufacturing in this study uses the phase inversion method. phase inversion is a method of making a membrane from a polymer in the form of a solution to a solid [5]. the process of mixing nylon solution with variations in the addition of tio2 mass fraction in this study resulted in 6 membrane samples. electrical conductivity is a measure of the ability of a material to conduct electric current [14]. the electric current in the material is carried by the ions contained in the material. electrical 50 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 47-52 eissn : 2747-173x submitted : july 1, 2020 accepted : september 21, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23544 conductivity measurements were carried out directly using the parallel plate method, from copper pcb plates carried out at room temperature. this test aims to determine the best nylon-tio2 mass fraction based on the measured electrical conductivity of the membrane. the measured electrical conductivities for the membrane are shown in table 1. table 1. the value of the electrical conductivity of the nylon-tio2 hybrid membrane tio2 concentration (wt%) electrical conductivity ̅ (s / cm) 0 (0.66 ± 0.04) ×10 -9 0.5 (1.21 ± 0.02) ×10 -9 1 (2.79 ± 0.38) ×10 -9 3 (4.23 ± 0.39) ×10 -9 5 (9.15 ± 5.71) ×10 -9 7 (2.31 ± 0.45) ×10 -9 the measurement results show that the addition of tio2 mass fraction increases the electrical conductivity of the membrane. the electrical conductivity of the nylon-tio2 membrane obtained in this study was around 0.66 × 10 -9 s/cm to 9.15 × 10 -9 s/cm. the greater the electrical conductivity indicates that the material is better at conducting electricity [14]. based on table 4.2, it can be seen that the lowest electrical conductivity value is obtained in the membrane sample a which is a nylon membrane without the addition of tio2, which is equal to (0.66 ± 0.04) × 10 -9 s/cm. according to pure nylon-6 has an electrical conductivity value of 10 -14 s/cm [16]. meanwhile, the electrical conductivity value of a pure nylon-6 membrane using the electrospinning method was 2.7 × 10 -9 s/cm [17]. the different results from the electrical conductivity obtained may be due to the use of nylon raw material and the membrane fabrication method used. however, the results obtained from the measurement of the electrical conductivity of the nylon membrane were not much different. figure 3. graph of the electrical conductivity of the nylon-tio2 hybrid membrane by measuring the parallel plate method the value of the electrical conductivity increases due to the increasing density and mobility of the charge carriers along with the addition of the mass fraction of tio2 into the nylon-tio2 hybrid 51 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 47-52 eissn : 2747-173x submitted : july 1, 2020 accepted : september 21, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23544 membrane [18]. in this study, the electrical conductivity value increased starting from the addition of tio2 mass fraction 0.5% (membrane b), 1% (membrane c), 3% (membrane d), up to 5% (membrane e), respectively. then the electrical conductivity value decreased when the mass fraction of tio2 was 7% (membrane f).the tendency of decreasing electrical conductivity is made possible by the existence of a maximum limit of the ratio between nylon and the addition of the mass fraction of tio2 to the membrane.the value of the largest electrical conductivity of the nylon-tio2 hybrid membrane was obtained at the addition of the mass fraction of tio2 5% (membrane e), which was (9.15 ± 5.71)×10 -9 s/cm. the greater the electrical conductivity of the membrane, the better the characteristics of the membrane in conducting ions. based on the research results, the best nylon-tio2 hybrid membrane was found in the addition of 5% tio2 mass fraction (membrane e). conclusions the best membrane is obtained when the electrical conductivity value is greatest. the greater the electrical conductivity value indicates that the ability of the membrane ion transport mechanism is getting better. the greatest electrical conductivity was obtained at the addition of 5 wt% tio2 mass fraction. acknowledgements the author would like to thank the lp2m university of jember for funding the research by hibah keris 2020. references [1] c. y. lai, a. groth, s. gray and m. duke, 2014, nanocomposites for improved physical durability of porous pvdf membranes, membranes, volume 4, no.1, page 55-78. [2] a. suhendi, 2007, pencirian membran mikrofiltrasi nilon-6, essay, bogor, institut pertanian bogor. [3] moerniati, s., aspriyanto, s. aiman, wahab, dan nurhasanah, 1998, preparasi membran poliamida dengan menggunakan proses phase inversion, serpong, puslitbang kimia terapan lipi. [4] c. k. chen and j.-k. kuo, 2006, nylon 6/cb polymeric conductive plastic bipolar plates for pem fuel cells, journal of applied polymer science, vol. 101 no.5, page 415–3421. [5] m. mulder, 1996, basic principles of membrane technology second edition, london, kluwer academic publisher. [6] s. b. chaudary, p. panday and shaikh tn, 2013, a review on polymer tio2 nanocomposites. international journal of engineering research and application, vol. 3 no. 05, page 1386-1391. [7] j. c. harper, pa christensen, ta egerton, tp curtis, and j. gunlazuardi, 2001, effect of catalyst type on the kinetics of the photoelectrochemical disinfection of water inoculated with e. coli, journal of applied electrochemistry, vol. 31 no. 6, page 623-628. 52 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 47-52 eissn : 2747-173x submitted : july 1, 2020 accepted : september 21, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23544 [8] v. sitorus, 2013, uji fotokatalis bahan tio2 yang ditambah dengan sio2 pada zat warna metilen biru, essay, lampung, university of lampung. [9] mahaningsih, t, 2011, kajian sifat listrik membran polisulfon yang didadah titanium dioksida (tio2), skripsi, bogor, institut pertanian bogor. [10] n. cheristiyani, 2011, kajian sifat listrik membran selulosa asetat yang didadah dengan titanium dioksida (tio2), essay, bogor, institut pertanian bogor. [11] juliandri, a. nurfadhillah, rukiah, m. nasi and r. a. lubis, 2019, synthesis and characterization of sulfonated pvdf tio2-natural zeolite nanocomposites membrane, key engineering materials, volume 881, page 147-152. [12] j. juansah, n. cheristiyani, k. dahlan and irmansyah, 2012, sifat listrik membran selulosa asetat-titanium dioksida, jurnal biofiska, volume 1 nomor 8, page 9-15. [13] e. r. apipah, 2013, sintesis dan karakteristik membran nilon yang berasal dari limbah benang, essay, bogor, institut pertanian bogor [14] a. junaedi, 2011, membran elektrolit dari komposit pva-lioh dengan nanopartikel silika terdispersi, essay, semarang, universitas negeri semarang. [15] f. azizah, 2008, kajian sifat listrik membran selulosa asetat yang direndam dalam larutan asam klorida dan kalium hidroksida, essay, bogor, institut pertanian bogor. [16] irzaman, a. agustina, r. n. komariah, and j. khabibi, 2014, electrical properties of indonesian hardwood case study: acacia mangium, switenia macrophylla and measopsis eminii, wood research, vol. 59, no. 4, page 695-704. [17] blythe ar and bloor d, 2005, electrical properties of polymers, first ed, new york: united states of america by cambridge university press, 1977, page 90-93. [18] chayad, f. a., a. r. jabura, dan n. m. jala, 2015, effect of mwcnt addition on improving the electrical conductivity and activation energy of electrospun nylon films, journal of modern science, volume 1 nomor 4, page 187-193. 10 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 study of the ferromagnetic magnetite resonance (fe3o4) forms of thin films using micromagnetic simulation syefira salsabila 1 , lutfi rohman 1,a and endhah purwandari 1 1 departmen of physics, faculty of mathematics and natural sciences, universitas jember, jember 68121, east java, indonesia a elrohman2@gmail.com abstract. fe3o4 is the strongest magnet among other iron oxides. magnetite fe3o4 is applied as a permanent magnet. the hysteresis curve of the permanent magnet fe3o4 has a coercivity field that is not too large so that the material has a good chance to be applied as an absorbent material for radar waves. micromagnetic simulations were carried out on fe3o4 material in the form of thin film against hysteresis curves and ferromagnetic resonances at various thickness variations and side length variations, and the relationship was seen with changes in the bandwidth of the radar wave absorption frequency if the thickness variation of the simulated material had the same multiple as the experimental material. the thickness variations in this study were 60 nm, 90 nm, and 120 nm, where the variations in the experiment were 0.6 mm, 0.9 mm, and 1.2 mm. micromagnetic simulation runs were performed to obtain the hysteresis curve and resonance frequency of the fe3o4 material. the simulation results show that the resonant frequency increases with increasing thickness (fixed side length). meanwhile, the relationship between the resonant frequency and the side length of the thin film is inversely related. changes in the resonant frequency of fe3o4 material are closely related to changes in the absorption frequency band of fe3o4 material. the hysteresis curve obtained shows that the fe3o4 material is a hard magnetic material. changes in the resonant frequency of fe3o4 material are closely related to changes in the absorption frequency band of fe3o4 material. the hysteresis curve obtained shows that the fe3o4 material is a hard magnetic material. changes in the resonant frequency of fe3o4 material are closely related to changes in the absorption frequency band of fe3o4 material. the hysteresis curve obtained shows that the fe3o4 material is a hard magnetic material. keywords: fe3o4, ferromagnetic resonance frequency, micromagnetic simulation introduction radar detection technology has grown rapidly every year. this technology has been delivered to a new material, namely radar absorbing material (ram). ram is a material that can absorb electromagnetic waves. an object coated with ram will not be detected by radio detection and raging (radar) because this material absorbs reflections and absorbs microwaves. the types of materials used as wave absorbers are dielectric and magnetic material [1]. magnetic materials depend on magnetic losses. magnetic losses are a state of loss of the magnetic field of a material and in general this value depends on the magnetic permeability of the material. an example of a material that has high permeability and can be used as an absorber of electromagnetic waves is iron oxide. this material is found in the form of minerals in the form of magnetite (fe3o4), maghemite (γ-fe2o3), and hematite (α-fe2o3). research on the absorption of electromagnetic waves has been carried out by shofiyatun experimentally to determine the effect of layer thickness on radar wave absorber [2]. from this research, it was found that the change in the absorption frequency bandwidth of the material to radar waves is proportional to the increase in thickness of the fe3o4 material. 11 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 this research uses magnetite fe3o4 which is iron oxide which is widely used commercially. the purpose of this study was to determine the effect of thickness variations and side length variations in the fe3o4 material on the resonant frequency and to see its relationship with changes in the absorption frequency band width of the radar waves if the variation in the size of the simulated material has the same multiple as the experimental material. theoretical background magnetite has the strongest magnetism among other iron oxides so that it is widely applied in everyday life [3]. magnetite has a spinel crystal structure with a cubic-shaped unit cell consisting of 32 oxygen ions, of which the gaps are occupied by fe 2+ and fe 3+ ions (figure 1). in the tetrahedral there are eight fe 3+ ions in each cell because it is in the middle of the tetrahedron where the four corners are occupied by oxygen ions. the remaining eight fe 3+ and eight fe 2+ ions are in the octahedral, because the oxygen ions around them occupy the corners of an octahedron occupied by the six oxygen atoms [4]. as with magnetic materials in general, the magnetic properties of magnetite, which are included in ferromagnetic materials, can be determined using the hysteresis curve [5]. the amount of coercivity determines whether the material is classified as soft magnetic or hard magnetic. materials that have a coercivity of more than 10 ka/m (hc > 10 ka/m) are called hard magnetic, while materials with a coercivity of less than 1 ka/m (hc < 1 ka/m) are called soft magnetic [6]. figure 1. magnetite unit cell ferromagnetic resonance (fmr) is the frequency at which the relative response amplitude is maximum. fmr occurs because magnetic materials oscillate when exposed to a field that oscillates periodically. the performance of magnetic-based devices is influenced by magnetization reversal and ferromagnetic resonance (fmr) which can increase the speed of reading and writing data on the device [7].research on magnetization reversal and fmr has been published experimentally or simulated by providing an external magnetic field or pulse signal. measurements using an fmr tool are carried out by placing the sample in a microwave resonant cavity and the sample is in the form of a thin layer as shown in figure 2. 12 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 figure 2. the principle of measurement using an fmr instrument is applied to microwaves or radio in the direction perpendicular to the magnetic field the theory development regarding fmr is carried out based on the relative orientation of the sample shape between h and m. magnetization has an important role in the influence of the shape of ferromagnetic materials on the resonance process. the equation regarding the dynamics of magnetization in fmr measurements in the form of the relationship between the external magnetic field, magnetization and demagnetization factors, can be written as follows [8]: (1) materials and methods figure 3. research flow diagram to obtain hysteresis curve and resonance frequency of fe3o4 material 13 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 the material used in this study is a hard magnet in the form of magnetite (fe3o4). fe3o4 material has a geometry in the form of thin film. the parameters used for the micromagnetic simulation consist of: saturation magnetization, anisotropy constant, and exchange constant. the cell size used is based on the exchange length size of the fe3o4 material with a damping factor of 0.05. this simulation uses two types of variations, namely the thickness and length of the thin film side to find the hysteresis curve and resonance frequency. table 1. fe3o4 material parameter for micromagnetic simulation data input parameter score ms [2] 8.68 x 105 a / m a [5] 1.2 x 10 -11 j / m k [5] -1.1 x 10 4 j / m3 α [5] 0.05 iex 8.7 nm a. simulation analysis to obtain resonant frequency with variations in thickness and side length of the fe3o4 material simulations to obtain resonant frequency values with variations in thickness and side length were carried out by inputting thickness and side length variations in the file (.geo) and material parameters (ms, a, k, iex, α) and kittel's calculations in equation 1 in file (. py). then the file is run using nmag. the output of this process (.frek) contains the resonant frequency value. the amplitude used to get the value of the resonant frequency through simulation is 1000 a / m. b. analysis to determine the relationship between the simulation results of ferromagnetic resonance (fmr) with changes in the bandwidth of the radar wave absorption frequency simulation for determining the correlation between ferromagnetic resonance (fmr) simulation results with changes in frequency band widthdone by providing various thickness variations on the thin film. the thickness varied in the experiment 0.6 mm, 0.9 mm, and 1.2 mm. meanwhile, in the simulation, the thickness varied from 60 nm, 90 nm, and 120 nm. then from these results it can be seen whether the simulation results of ferromagnetic resonance (fmr) have a relationship with changes in the bandwidth of the radar wave absorption frequency if the simulated material size variation has the same multiple as the experimental material. results and discussion hysteresis curve the magnetic properties of a material can be seen from the hysteresis curve. the hysteresis curve is a curve that shows the relationship between the magnetization (m) that occurs in a material and the external magnetic field (h). figure 4 is the hysteresis curve of the fe3o4 material obtained in this simulation. 14 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 figure 4. fe3o4hysteresis curve the change in magnetization in the material occurs with the addition of the external magnetic field. the external magnetic field will continue to increase so that the magnetization reaches a saturation state as shown in figure 4 number 1 with a magnetic value of 866 ka/m. after reaching the saturation point, the magnetization will reach a remanence state as shown in figure 4 number 2 with a magnetization value of 584 ka/m. this process is continued by reversing the direction of the magnetic field h given and continuously increasing so that the magnetization value becomes zero. the value of the external magnetic field given when the magnetization reaches zero is called the coercivity field. the simulation results show that the coercivity field is 24 ka/m where hc > 10 ka/m so that information is obtained that the material fe3o4 is hard magnetic [9]. ferromagnetic resonance frequency ferromagnetic resonance (fmr) is the frequency at which the relative response amplitude is maximum. fmr occurs because magnetic materials oscillate when exposed to a field that oscillates periodically. the performance of magnetic-based devices is influenced by magnetization reversal and ferromagnetic resonance (fmr) which can increase the speed of reading and writing data on the device [7]. the ferromagnetic resonance frequencies are obtained in the ghz range using micromagnetic simulations.table 2 is the result of the resonant frequency generated through kittel's simulation and calculations. kittel's calculation is used as a comparison or reference for the truth of the simulation results according to theory. based on kittel's calculations, the greater the thickness given to the material, the greater the resonant frequency. 15 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 table 2. the magnitude of the ferromagnetic resonance frequency (fmr) with respect to thickness variations with a fixed side length no. thickness (nm) side length (nm) ratio fmr calculated by kittel (ghz) * fmr simulation result (ghz) 1. 60 15 4 10.4 10.4 2. 90 15 6 11.9 11.4 3. 120 15 8 12.5 12.3 the results obtained in table 1 then graphed the relationship between fmr and various thicknesses of the fe3o4 material. figure 5 explains that the greater the thin film thickness of the fe3o4 material (fixed side length), the greater the resonant frequency. this is because the greater the thickness of the material, the greater the magnetic material content. the results obtained are in accordance with the theory, where the thickness of the material given is proportional to the resulting resonant frequency. figure 5. graph of the resonance frequency relationship to thickness variations the simulation results obtained in this study indicate that the increase in the resonant frequency of the material is proportional to the increase in thickness of thin film fe3o4. if these changes are further analyzed, there is a correlation between the results of simulation research and experimental research conducted by shofiyatun [2]. the thicker the layer, the higher the frequency value and the wider the absorption band. 16 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 table 3. the magnitude of the ferromagnetic resonance frequency (fmr) for variations in side length with a fixed thickness no. side length (nm) thickness (nm) ratio fmr simulation result (ghz) 1. 60 15 4 13.7 2. 90 15 6 12.7 3. 120 15 8 12.6 table 3 is the result of the frequency generated through micromagnetic simulations with variations in side length values. in the table, it can be seen that the greater the side length, the smaller the frequency. this is because the spin position becomes more irregular as the side length of the fe3o4 material increases. the results obtained in this study are in accordance with previous research conducted by moh. imron, where the greater the diagonal value or side length of the material, the smaller the resulting frequency [10]. figure 6. graph of the resonance frequency relationship to the variation in length of side of fe3o4 figure 6 shows the relationship between the resonant frequency of the material and the length of the thin film side of the fe3o4 material at a fixed thickness value of 15 nm. the graph explains that the greater the length of the thin film side of the fe3o4 material (fixed thickness), the smaller the resonance frequency obtained. it can be said that the value of the side length is inversely proportional to the resulting frequency. 17 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 conclusions the results obtained in this study are variations in thickness (fixed side length) and variations in side length (fixed thickness) which can affect the ferromagnetic resonance frequency of the fe3o4 material produced. the value of the resonant frequency increases with increasing thickness of the material. meanwhile, the variation in side length (fixed thickness) results in a smaller frequency value as the side length increases. the simulation results of ferromagnetic resonance (fmr) have a relationship with changes in the absorption frequency band width of the radar waves if the simulated material size variation has the same multiple as the experimental material, where the change in the absorption frequency band of the material to radar waves is proportional to the increase in thickness of the fe3o4 material. from this, we can say that the change in the resonant frequency of the fe3o4 material is closely related to the change in the absorption frequency bandwidth of the fe3o4 material. references [1] y. wang, t. li, l. zhao, z. hu, and y. gu, 2011, research progress on nanostructured radar absorbing materials. journal of energy and power engineering, volume 3, page 580584. [2] shofiyatun, 2017, magnetite radar absorbent coating (fe3o4) using anti-corrosion paint. thesis, surabaya, fmipa, its. [3] a.s. teja, and p.y. koh, 2009, synthesis, properties, and application of magnetic iron oxide nanoparticles. progress in crystal growth and characterization of materials, volume 55, page 22-45. [4] l.k. sholihah, 2010, synthesis and characteristics of fe3o4 nano particles from iron sand and fe3o4 commercial materials (aldrich). thesis, surabaya, department of physics, f mipa, its. [5] j.m. coey, 2010, magnetism and magnetic materials. cambridge: cambridge university press. [6] c.b. carter, and m.g. norton, 2007, ceramic materials: science and engineering, springer. [7] ismail. 2013. micromagnetic study of magnetization process and ferromagnetic susceptibility spectrum of diamond shaped elements. thesis, jakarta, university of jakarta. [8] c. kittel, 1948, on the theory of ferromagnetic resonance absorption. physical review volume 73, no 2, page 155. [9] s. rösler, p. wartewig, and h. langbein, 2003, synthesis and characterization of hexagonal ferrites bafe12-2xznxtixo19 (0 ≤ x ≤ 2) by thermal decomposition of freezedried precursors. crystal research and technology: journal of experimental and industrial crystallography, volume 38, no 11, page 927-934. 18 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 10-18 submitted : january 2, 2020 accepted : march 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26414 [10] m. imron, 2019, studi resonansi feromagnetik bahan la1-xsrxmno3 (lsmo) berbagai bentuk pilar menggunakan simulasi mikromagnetik. skripsi, jember, fmipa, universitas jember 19 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 design study of gas cooled fast reactor (gfr) with uranium plutonium carbide (uc-puc) as fuel with addition protactinium (pa231) alvi nur sabrina 1,a , arindi kumala sari 1 , laela nur janah 1 , and m. rizqi maulana 1 1 department of physics, faculty of mathematics and natural sciencs, university of jember, jalan kalimantan no 37 jember 68121, indonesia a sabrinaalvi31@gmail.com abstract. analysis performance of uranium plutonium carbide (uc-puc) as fuel in gas cooled fast reactor (gfr) with addition of protactinium as a burnable poisons has been done. neutronic analysis in this research was carried out using the srac code from jaeri with a nuclear library based on jendl 4.0. the calculation is carried out by two steps, the first step is the pij calculation which calculates the fuel cell and the second step is the citation calculation which calculates the various configurations of the reactor core. the first calculation determines the k-eff value in a homogeneous core configuration. the results obtained show that the percentage of 10% is the sloping result with a k-eff value of 1%. the second calculation determines the k-eff value in the heterogeneous core configuration. the results obtained indicate that the fuel variation 8% -10% -12% is the most critical percentage with a peak power density value of less than 100 watt/cc. furthermore, the addition of protactinium with a variation of 0% to 5%. at a protactinium 4% percentage and 63% fuel fraction, the excess reactivity value is 1.02% or close to 1% which indicates that the reactor is in a critical condition. keywords: gfr, uranium plutonium carbide, protactinium introduction generation iv reactors consist of six types of reactors, i.e. gas cooled fast reactor (gfr), lead cooled fast reactor (lfr), molten salt reactor (msr), sodium cooled fast reactor (sfr), supercritical water cooled reactor (scwr), and very high temperature reactor (vhtr) [1]. one of the advantages of generation iv reactors is the inheren safety, sustainability, non-proliferation, and is more economical than other power plants. research on gfr has been done previously by syarifah et al. research on the design study of 200mwth gas cooled fast reactor with nitride (un-pun) fuel long life without refueling using pij dan citation calculation with data library jendl 3.2 has been carried out, optimum result k-eff value is 1.10142 with excess reactivity value 1.403% [2]. other research has also been carried out regarding neutronic analysis of thorium nitide (th, u233) n fuel for 500mwth gas cooled fast reactor (gfr) long life without refueling with pij dan citaion calculation and data library jendl 4.0, the resulting k-eff value is 1,01229 with excess reactivity value 1.21% [3]. and other studies on gfr with un-pun fuel have been carried out by syarifah [4-7]. design study gfr 300 mwth was carried out with variations fuel fraction with uranium plutonium carbide and variations addition of protactinium as a burnuble poison. 20 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 theoretical background nuclear power plant (pltn) is an alternative energy that can be used to support the world's electricity needs. nuclear power is considered the best source of choice for electricity generation [8]. further development of nuclear power is needed to meet future energy demands on demand. designing a nuclear system needs to emphasize a highest level of safety. generation iv reactors include a future nuclear system which has four goals, namely economy, sustainability, safety, reliability and proliferation. one of the generation iv reactors is the gfr, which is a helium gas cooled fast reactor using the fast neutron spectrum. the function of the cooling gas is an inert chemical capable of operating at high temperatures without corrosion and toxicity and a single phase that eliminates boiling [9]. the reaction that occurs in the reactor is called a nuclear reaction, where the nuclear reaction is the collision of two nuclei or two particles which produce a nucleus or particle that is different from its origin [5]. nuclear reactors in the process require a fuel that is used to produce nuclear energy. fuel is divided into two, namely fisil material and fertil material [10]. the fuel used is plutonium uranium carbide with the addition of protactinium 231 as a burnuble poison. protactinium has a large catch section and is used to reduce excess reactivity at the start of combustion. the use of protactinium is also used to reduce the world's waste fuel [11]. this research was conducted by varying the fuel fraction from 60% to 65% and varying the protactinium 0% to 5%. materials and methods determination of fuel, cladding, and coolant in the reactor can affect the safety factor and reactor economy. in this study, the pin design geometry uses the hexagonal cell geometry as shown in figure 1. the geometry is divided into six regions, where the first three areas are the fuel area, the next one is the cladding area, and the next two are the coolant areas. the active core diameter is 240 cm and the active core height is 100 cm. table 1 shows the reactor design parameters that have been designed. table 1. reactor design parameter design parameters specification power 300 mwth fuel material uranium plutonium carbide (uc) cladding material silicon carbide (sic) coolant material helium (he) fuel fraction 60% 65% cladding fraction 10% coolant fraction 25% 30% active core diameter 240 cm active core height 100 cm reflector axial & radial width 50 cm burn-up time 20 years 21 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 figure 1. cell geometry in this study the calculations were carried out using the srac code. srac (standard reactor analysis code) is a code developed by jaeri (japan atomic energy agency). the srac is designed for neutronic calculations of various types of reactors. the nuclear data library used is jendl 4.0 which is the latest nuclear database developed by japan. srac includes effective microscopic and macroscopic production, and static cell and core calculations including burn-up analysis. first, the pij calculation which calculates fuel cells in the form of hexagonal cells using the collision probability methods (cpm) method. in the pij calculation we get the k-inf value, burn-up analysis and others. after that, proceed with the calculation of the reactor core using citation calculations with various core configurations [12]. results and discussion analysis performance of uranium plutonium carbide (uc-puc) as fuel in gas cooled fast reactor (gfr) with addition of protactinium as a burnuble poisons has been done. the first step in the calculation is to determine the k-eff value based on the variation of homogeneous and heterogeneous fuels with a fuel fraction of 60%, cladding 10%, and coolant 30%. figure 2. is a graph of the k-eff value in a homogeneous core configuration with a fuel value variation of 5% to 15%. the graph of the k-eff value in the homogeneous core configuration shows that 10% fuel variation is the most sloping result, with a delta k-eff value of 0.007638 or equal to 1%. 22 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 figure 2. the k-eff value in a homogeneous core configuration the next calculation uses a heterogeneous core configuration, where the fuel used has three variations in value with an average of 10%. figure 3. is the result of calculating the k-eff value obtained in the heterogeneous core configuration. fuel variation with a value of 8% -10% -12% is the variation that shows the most critical results, with a peak power density value less than 100 watt/cc. the power distribution to the radial direction of the mesh in the homogeneous and heterogeneous core configurations in the reactor core can be seen in figure 4. figure 3. the k-eff value in a heterogeneous core configuration 0 5 10 15 20 0.7 0.8 0.9 1.0 1.1 1.2 1.3 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (years) pu 5% pu 6% pu 7% pu 8% pu 9% pu 10% pu 11% pu 12% pu 13% pu 14% pu 15% 0 5 10 15 20 1.050 1.055 1.060 1.065 1.070 1.075 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (years) f1=7%, f2=10%, f3=13% f1=7.5%, f2=10%, f3=12.5% f1=8%, f2=10%, f3=12% f1= 8.5%, f2=10%, f3=11.5% f1=9%, f2=10%, f3=11% f1=9.5%, f2=10%, f3=10.5% 23 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 figure 4. the power distribution to the radial direction of the mesh in the homogeneous and heterogeneous core configurations figure 5. describes the effect of the addition of protactinium (pa-231) on the k-eff value. the addition of 0% to 5% protactinium causes a decrease in the k-eff value during combustion. the variation of protactinium addition of 4% showed the most effective results, with a delta k-eff value of 0.009931 (k-eff ~ 1%). figure 5. the k-eff value with the addition of pa (0%-5%) 0 5 10 15 20 25 30 35 0.0 0.5 1.0 1.5 2.0 p o w e r d e n s it y ( w a tt /c c ) mesh (cm) homogen heterogen 0 5 10 15 20 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (years) pa 0% pa 1% pa 2% pa 3% pa 4% pa 5% 24 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 figure 6 explains the effect of variations in the fuel fraction from 60% to 65%, where the variation in the fuel fraction of 63% shows the k-eff increased significantly with an average value of k-eff ~ 1 and the maximum excess reactivity value obtained is 1, 02%. the final result in figure 7 shows that the calculation of the k-eff value at the variation of the 63% fuel fraction with the addition of pa-231 4%, results in the reactor with the most critical condition with a maximum excess reactivity value of 1.02%. figure 6. the k-eff value (pa 4%) with variations fuel fractions (60%-65%) figure 7. optimization results design k-eff value 0 5 10 15 20 0.990 0.995 1.000 1.005 1.010 1.015 1.020 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) buen-up time (years) fuel fraction 60% fuel fraction 61% fuel fraction 62% fuel fraction 63% fuel fraction 64% fuel fraction 65% 0 5 10 15 20 1.000 1.002 1.004 1.006 1.008 1.010 1.012 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (years) f1=8%, f2=10%, f3=12%, pa=4%, fuel fraction=63% 25 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 conclusions analysis performance of uranium plutonium carbide (uc-puc) as fuel in gas cooled fast reactor (gfr) with addition of protactinium as a burnuble poisons has been done. the k-eff value which indicates the criticality level of the reactor, can be reduced during the combustion period to reach a critical state in the reactor by adding pa-231 0% to 5% and varying the fuel fraction from 60% to 65% to produce the k-eff value. which indicates the reactor is in a critical state (k-eff ~ 1). the results obtained show that, the addition of protactinium 4% with a fuel fraction of 63% results in a k-eff ~ 1 value and produces a maximum excess reactivity of 1.02%. acknowledgements the authors gratefully acknowledge the support of nuclear team for the enthusiastic and helped in conducting the reasearch and would like to thank dr. ratna dewi syarifah, s.pd., m.si., for lots of guidance and helpful discussion. references [1] gif (the generation iv international forum), 2014, technology roadmap update for generation iv nuclear energy system, the oecd nuclear energy agency. [2] r. d. syarifah, y. yulianto, z. su’ud, k. basar, and d. irwanto, 2016, design study of 200mwth gas cooled fast reactor with nitride (un-pun) fuel long life without refueling, in matec web of conferences (edp sciences), volume 82, page 03008. [3] r. d. syarifah, z. su’ud, k. basar, and d. irwanto, 2017, fuel fraction analysis of 500 mwth gas cooled fast reactor with nitride (un-pun) fuel without refueling, in journal of physics: conference series, iop publishing, volume 799, page 012022. [4] r. d. syarifah, z. su’ud, k. basar, and d. irwanto, 2016, the prospect of uranium nitride (un-pun) fuel for 25-100mwe gas cooled fast reactor long life without refueling, in journal of physics: conference series, iop publishing, volume 776 page 012103. [5] r. d. syarifah, z. su’ud, k. basar, and d. irwanto, 2017, comparative study on various geometrical core design of 300 mwth gas cooled fast reactor with un-pun fuel longlife without refueling, in journal of physics: conference series, iop publishing, volume 877 page 012064. [6] r. d. syarifah, z. su’ud, k. basar, and n. kurniasih, 2018, design study of 600 mwt long life modular gas cooled fast reactors, in journal of physics: conference series, iop publishing, volume 1090 page 012021. [7] r. d. syarifah, z. su’ud, k. basar, and d. irwanto, 2018, neutronic analysis of un-pun fuel use fi-itb-chi code for 500mwth gfr long life without refueling, in journal of physics: conference series, iop publishing, volume 1090 page 012033. 26 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 19-26 submitted : january 10, 2020 accepted : march 15, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26415 [8] gif (the generation iv international forum), 2002, a technology roadmap for generation iv nuclear energy system, u.s doe nuclear energy research advisory committee. [9] z. alatas, s. hidayati, m. akhadi, m. purba, and m. sofyatiningrum, 2015, buku pintar nuklir, adi asmara. [10] j. j. duderstadt, and l. j. hamilton, 1976, nuclear reactor analysis. johnwiley & sons, inc., new york. [11] m.n subkhi, z. su'ud, and a. waris, 2013, netronic design of small long-life pwr using thorium cycle, in advanced materials research, trans tech publications ltd, volume 772, page 524-529. [12] k. okumura, t. kugo, k. kaneko, and k. tsuchihashi, 2002, srac (ver. 2002): the comprehensive neutronics calculation code system. japan atomic energy research institute, tokai-mura, japan. 10 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 effect of write head movement on magnetic spin domain reversal of nanocube co/pd alloy material using micromagnetic simulation ilham heru baskoro 1,a and merinda lestari 1 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no. 37, jember 68121, indonesia a herubaskorowinchester@gmail.com abstract. an analysis of the effect of the write head movement on the reversal time of the domain spin with magnetic co/pd on the magnetic recording layer has been carried out through micromagnetic simulation. the magnetic recording layer is modeled in the form of cubes (nanocubes) which consists of 5 domain spin. the write head, which is a transduser, moves along the domain spin to write data in the form of magnetic spins, which represent the bits on the magnetic recorder perpendicular. the results of this simulation are a profile of changes in the total magnetic field and reversal time of the domain spin when writing magnetic data for 6 nanoseconds. the calculation used in this study is an analytical calculation regarding the reversal time of the magnetic domain spin of the co/pd alloy material. the formulation for calculating the reversal time of domain-spin magnetization is a combination of graphical analysis and analytical calculations with visualization of the magnetic spin configuration that consisting of 5 domains spin. this simulation was carried out using the finite element method and obtained a saturation field value of the magnetic alloy co/pd (hs) material of 2.5 x 10 5 a/m and a write head (hwh) field that must be applied to the magnetic recording layer in order to reverse the uniform domain spin is 7.3 x 10 6 a/m. each size of the domain spin requires a different write head, the smaller the nanocube size, the greater the write head field applied to the magnetic recording layer. meanwhile, the effective write head field amplitude that is suitable for the 20 nm domain spin is 8.3 x 10 6 a/m. a significant change in the total field occurs when the domain spin reverses 3 times in the first domain spin (n1), the third domain spin (n3) and the fifth domain spin (n5). the total field value when t=0.42 ns ( first domain spin reversal) is 73.69376 a/m, then the total field at t=0.42 ns (third domain spin reversal) is 3443.197 a/m and the current total field t=0.42 ns (fifth domain spin reversal) of 5480.696 a/m. keywords: write head, perpendicular magnetic recorder, finite element method, domain spin, saturation field (hs). introduction one of the potential materials for spintronic device applications is ferromagnetic materials. naturally, ferromagnetic materials have spontaneous magnetizing property known as a magnetic domain. the configuration of the spin structure in the magnetic domain can be controlled using a magnetic field. as a result, there is a change in the configuration of the spin direction in the magnetic domain which is interpreted as a process of changing the magnetization (magnetization reversal). the changes in magnetization in ferromagnetic materials are fundamental to magnet based data storage devices [1]. ferromagnetic materials have a domain wall which is formed from the competition between exchange energy and anisotropy enenrgy. exchange energy is used to thicken the domain wall. however, the thicker domain wall will cause the spin direction transisition. this will increase the anisotropy effect. if this effect is increased continously, it will make the domain wall thinner. 11 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 the competition between exchange energy and anisotropy energy is characterized by the exchange length. √ (1) where, is exchange length , a is exchange stiffness constant ⁄ , is the air permeability ⁄ , is saturation magnetization ⁄ [2]. on the hard disk, information is generally stored on a ferromagnetic granular film that is in a magnetized state. the granular medium is the composition of the seeds, which are located with the same structure crystal that making the magnetization parallel straight to one axis, which is called the easy axis. a systematic understanding of the magnetization dynamics in write heads is essential in understanding the effects of perpendicular magnetic recording (pmr) to increase bit density and data rates. however, recently it is only possible to compute the magneto dynamics of the overall system interaction of the write dead, domain spin data media (dl), and soft undermedia (sul) [3]. the biggesrt problem at this time is that perpendicular magnetic recording is limited by trilemma caused by superparamagnetic limits, namely thermal stability, grains size, and writing capability when data storage density is increased. the smaller size of the grains, a larger write current consumption is required. in the cross-secion configuration of the bit that perpendicular requires hamr (heat assisted magnetic recording) technology, which uses illumination or light from a laser to write data on the medium. hamr is an attempt to take advantage of the dependency of high temperature from magnetic anisotropy, by increasing the temperature can reduce the coercivity of the medium significantly so that data recording can appear with a small write field [4]. another research that has been done is the micromagnetic study of patterned media. in this study, a material for perpendicular recording medium was used, namely the multimedia structure of co/pd which has the perpendicular orientation to the same magnetic media with co medium with thickness (0.2-0.3 nm). the magnetic recording medium for patterned media is based on the multimedia co/pd island with a domain spin microstucture measuring 10 nm and thick 15 nm. the size of the separated magnetic island is about 30 x 30 nm 2 and the bits separated by a 60 nm longitudinal peak and a 250 nm radial peak yield a storage density of 180 gbit/in 2 [5]. materials and methods the initial stage in this research is that the domain spin configuration is modeled in 3d and the grains geometry is determined according to the separation gap between each nanoisland, which is 10 nm. in this study, the nanoisland size was 20 nm then varied (5-20 nm). 12 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 figure 1. the size of perpendicular domain spin (nanometer) the research was conducted using publicly licensed software, namely nmag (nano magnetic) which can be run on the gnu/ linux operating system. the method used in this research is the finite element method. the basic concept of the finite element method is to solve a problem by dividing the object of analysis into finite small parts. these small pieces are then analyzed and the results are recombined to find a solution for the whole area. this micromagnetic simulation uses the formulation of time differential equations order-one, as follows: ( ) (2) the variation of the write head field is 1.0 x 10 6 a/m, 7.2 x 10 6 a/m, 7.3 x 10 6 a/m, 8.3 x 10 6 a/m to 83 x 10 6 a/m. while the geometry of the material used is 20 nm for the nanocube side. nanocube-shaped co/pd material parameters can be seen in table 1. table 1. nanocube-shaped co/pd material parameters parameter value ms 4.2126 x 10 5 a/m a 30 x 10 -12 j/m k 5.4 x 10 5 j/m 3 lex 16.4 nm after inputting all the co/pd material parameters, the output data will be obtained in the form of a .vtk file and a .ndt file. the .vtk file then used to visualize the domain structure. the visualization can show the direction of spin and the magnetization value of the co/pd material. furthermore, the results are represented in the form of a graph of the total magnetic field relationship to time (htot-t) from the .ndt file. in addition, a domain spin reversal time analysis was carried out related to the dynamics of the write head movement due to the influence of the amplitude variation of the write head field, on the simple moving of the write head phenomenon by varying the write head field on the same domain spin geometry and finding the best write head field for each size. results and discussion analysis of the relationship between the saturation field and the write head field to be applied the relation between the two was analyzed based on two different simulations, namely the simulation of the hysteresis curve of the magnetic co/pd material and the simulation of the effect of write head movement on the magnetic recording medium. in this discussion, an 13 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 explanation of the saturation field of magnetic co/pd material on the hysteresis curve is presented and its relation to the change in the total field (noise) in the magnetic recording medium during the data writing process for 6 nanoseconds. figure 2. hysteresis curve of the domain spin of co/pd magnetic material with side size of 20 nm nanocube. figure 2 is a hysteresis curve showing the hs saturation field of the co/pd magnetic material as many as 2.5 x 10 5 a/m. the saturation field hs is the amount of field needed to achieve saturation (saturation state0 and as initial information in analyzing how much the write head field needs to be applied to 20 nm co/pd grains to cause a magnetization reversal domain spin. the applied write head field or the htrand write head field must satisfy htrand > hs so that the write head field is not applied below the saturation field value. the simulation of the effect of write head movement on the magnetic recording medium is carried out by varying the amplitude of the write head field to obtain information abaout the domain spin response by applying a write head field to the magnetic recording medium of 2.5 x 10 5 -7.2 x 10 6 (a/m). figure 3 shows a reversal of the domain spin magnetization which is irregular and the noise in the medium that tends to be stable. the applied write head field is then enlarged to 7.3 x 10 6 a/m, so that the regular domain spin magnetization reversal occurs as shown in figure 4.6. this is done to obtain the effective write head field and domain spin reversal time. figures 3-5 show the reversal orientation on the domain spin with spin down. spin down 14 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 figure 3. first spin (island) domain reversal at time (t=0.42 ns) on the magnetic recording medium figure 4. second spin (island) domain reversal at time (t=2.42 ns) on the magnetic recording medium figure 5. third spin (island) domain reversal at time (t=4.42 ns) on the magnetic recording medium figure 6. graph of the total field of domain spin change on recording media for 6 nanoseconds with a write head field amplitude of 7.3 x 10 6 a/m spin down spin down 15 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 application of the best write head field for each side size variation of nanocube co/pd this section discusses the application of the best write head fields for each size variation of nanocubes or grains. the small nanocube size is needed in perpendicular magnetic recording technology which requires a larger write head field consumption because the coercivity of the perpendicular recording medium is greater than that of the magnetic recording medium in general. below is the variation in the size of the co/pd nano cube under the critical geometry of the magnetic co/pd material. a) application of the best write head field for the 5 nm side sized nanocube figure 7. the first domain spin reversal of the magnetic recording medium at t = 0.42 ns figure 8. the second domain spin reversal of the magnetic recording medium at t = 2.42 ns figure 9. the third domain spin reversal of the magnetic recording medium at t = 4.42 ns spin down spin down spin down 16 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 figure 10. graph of the total field change againts the time for 6 nanoseconds on a 5 nm domain spin with a write head field of 9.5 x10 7 a/m b) application of the best write head field for the 20 nm side sized nanocube figure 11. the first domain spin reversal of the magnetic recording medium at t = 0.42 ns figure 12. the second domain spin reversal of the magnetic recording medium at t = 2.42 ns spin down spin down 17 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 figure 13. the third domain spin reversal of the magnetic recording medium at t = 4.42 ns figure 14. graph of the total domain spin field change in recording media for 6 nanoseconds with a domain spin side of 20 nm table 2. the suitability of the write head field applied to each nanocube size variation no. the size of nanocube [nm] write head field amplitude [a/m] 1 5.0 95 x 10 6 2 7.5 53 x 10 6 3 10.0 26 x 10 6 4 12.5 17 x 10 6 5 15.0 9.7 x 10 6 6 17.5 8.7 x 10 6 7 20.0 8.3 x 10 6 in table 2 above, it is explained that each nanocube size has the best write head field based on a graphical analysis of the system total magnetic field change and the timing diagram in accordance with the previous discussion. based on the above discussion, it has been researched and obtained the best write head field for each grains size of the co/pd allor material, where the graph of the total magnetic field changes only changes significantly when the domain spin reversal occurs and during the transition time, the total magnetic field value is relatively small hence negligible, or relatively low noise from the magnetic recording medium. basically, the substance of the main study regarding noise in magnetic recording medium is related to the granularity of the medium. the total field value of the magnetic spin down 18 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 10 – 18 submitted : february 19, 2019 accepted : april 22, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20556 recording medium which changes due to a given or applied write head field can be specifically described, because the recording medium is a thin medium or thin film that has strong magnetic interactions and tightly arranged, an effective write head field is needed so that the total magnetic field changes significantly when the domain spin reversal occurs. the size of the grains geometry of the co/pd alloy material required the smallest size, in this study the nanocube geometry (5-20) nm was examined. table 3. the average domain spin reversal times for each domain spin size no. the size of spin domain [nm] average domain spin reversal time [s] pertama kedua ketiga 1 5.0 0.42 2.42 4.42 2 7.5 0.42 2.42 4.42 3 10.0 0.42 2.42 4.42 4 12.5 0.42 2.42 4.42 5 15.0 0.62 2.62 4.62 6 17.5 0.42 2.42 4.42 7 20.0 0.42 2.42 4.42 conclusions the simulation results produce that the write head field appied to the magnetic recording medium must be greater than the saturation field of the co/pd magnetic material where hs = 2.5 x 10 5 a/m and to achieve a regular domain spin reversal, the write head of hwh = 7.3 x 10 6 a/m (about 30 times as big) is needed. the greater the amplitude value of the write head field will affect the change in the total magnetic field and the time of domain spin reversal. the write head field amplitude is given starting from 1.0 x 10 6 a/m until it reaches an effective write head field of hwh = 8.3 x 10 6 a/m. the smaller the size of the co/pd grains (nanocubes), the greater the write head field that needs to be applied to the magnetic recording layer to cause a magnetization reversal in a regular domain spin. references [1] a t widodo, 2013, micromagnetic study of domain structure dynamics in ferromagnetic materials py, ni, fe, and co nanosprehe model, thesis, universitas indonesia press, depok, indonesia. [2] s chikazumi and s h charap, 1964, physics of magnetism, john wiley & sons, inc. [3] l schrefl, m e schabes, d suess and m stehno, 2004, dynamic micromagnetic write head fields during magnetic recording in granular media, ieee trans. magn., vol. 40, page 2341– 2343. [4] t rausch, 2002, optical data storage, conf. spie proc. 4342, 502 [5] j fidler, k h oh, t schrefl, d suess, and j lee, 2007, magnetic characteristics of ferromagnetic nanotube, journal of magnetism and magnetic materials, 310, page 24452447. 1 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 protein adsorption on modified bacterial cellulose bambang piluharto 1,2,a , fitri sulistyowati 2 , dwi indarti 1,2 , busroni 1,2 , d. setiawan purwo handoko 1,2 1 biomaterial research group, universitas jember, jember 68121, east java, indonesia 2 department of chemistry, faculty of mathematics and natural sciences, universitas jember, jember 68121, east java, indonesia a bampito.fmipa@unej.ac.id abstract. the protein adsorption was interesting study, especially in the biological fluidic application. in the present study, we study the protein adsorption behavior on the bacterial cellulose and modified bacterial cellulose. in here, bacterial cellulose was modified by acid hydrolysis using hydrochloric acid. the contact time and ph were used as variable to study protein adsorption behavior on the modified bacterial cellulose. as the results, based on functional group analysis, there are not different between bacterial cellulose and modified bacterial cellulose. however, after modification, there was increasing of crystallinity of bacterial cellulose from 84.5% to be 87.7%. in the protein adsorption study, increasing the contact time increase percent adsorption until contact time of 90 minutes, however the further contact time relatively constant. the protein adsorption on both of bacterial cellulose and modified bacterial cellulose decreases, following the increase of ph. keywords: bacterial cellulose, protein adsorption, acid hydrolysis introduction bacterial cellulose (bc) is cellulose that biosynthesized by certain bacteria, e.g, rhizobium spp., agrobacterium spp., acetobacter spp., and alcaligenes spp. compare with cellulose from plants, bc have advantageous properties such as high purity, high crystallinity, and high tensile strength. as a result of its advantageous properties, bc have been widely used in various field applications such biomedical, food industry and paper industry [1-3]. nanometric dimension of bc fibres lead to high surface area and potential to be adsorbent material. using bc as adsorbent have been used for dyes, heavy metals and protein [3,4]. protein adsorption is interested study, especially for biomedical applications. various chemically modified of bc have been developed for protein adsorption, phosphorylation bacterial cellulose (pbc), querterner ammonium bacterial cellulose (qabc), and carboxymethyl bacterial cellulose (cbc) and acid hydrolysis-base were some modified of bc for protein adsorption [5-8]. acid hydrolysis is one of the modified cellulose that have many used to generate cellulose nano crystal (cnc) with high crystallinity and high surface area [9]. the aim in this work is modied bacterial cellulose by acid hydrolysis and used it as adsorbent for protein adsorption. in here, hydrochloric acid was used as hydrolysis agent. analysis structure, crystallinity and surface charge group were used to observed modified bacterial cellulose. study adsorption was carried by batch method with various contact time and ph. 2 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 methods preparation of bacterial cellulose bacterial cellulose is produced from nata de coco with a 10-day fermentation period. nata de coco 10 kg is cut into 2 x 2 cm small boxes to make boiling easier. nata de coco is boiled with 2% naoh (w/v) at 70 °c for 1 hour to remove acetic acid, urea, and residual fermented sugar [10]. nata de coco is then washed with water repeatedly and the ph of the washing water is measured using ph meter to ph 7 (neutral). nata de coco is blended with maximum speed until it becomes porridge. nata de coco porridge is filtered and dried in an oven at 95 o c for 8 hours. the nata de coco plate produced from the oven process is blended until smooth. nata de coco powder is sieved with a 60 mesh sieve and the powder is taken through the sieve. modification of bacterial cellulose hcl 6 m of 480 ml is put into a round bottom flask and stirred with the stirrer to a temperature of 70 °c. then, 8.0009 grams of bacterial cellulose powder are added to a round bottom flask [11]. the mixture is stirred with the stirrer for 2 hours. the suspension is added with distilled water to a volume of 1000 ml to stop the reaction. the suspension is centrifuged at 10,000 rpm for 10 minutes. the ph of the supernatant after centrifugation was measured using a universal ph indicator to ph 7 (neutral) [11]. neutralizing bacterial cellulose was then 15 minutes ultrasounded with ultrasonic branson sonifer-250 power 250 w, electrical: 100 v, 50/60 hz, 3 a. then centrifuged and the resulting pellet was dried in an oven at 50 o c for 30 minutes. the result is further refined with mortar and pestle [12]. conductometric titration bacterial cellulose powder of 0.5000 grams modified are put into a 1000 ml three-neck flask, then 250 ml of 0.001 m. nacl is added to the mixture and then added to 5 ml of 0.05 m hcl solution. the solution is stirred with the stirrer and its conductivity is measured with a conductometer that has been calibrated with 0.01 m kcl solution. the solution is added naoh gradually with an initial volume of 0.5 ml 0.01 m naoh to approach the turning point. when approaching the turning point of 0.1 m as much as 0.1 m in addition to know the exact initial volume when hcl runs out. the addition of naoh is carried out gradually until the value of conductivity is constant. measurement of conductivity at room temperature under nitrogen gas pressure [13]. the number of carboxyl charge groups (coo-) can be calculated from the titration curve using equation 1. m vvc )12( (mmol/kg)coo   (1) where, c is concentration of naoh solution (mmol l-1), m is sample dry weight (kg), v1 is the volume of naoh is consumed at the first intersection point (l) and v2 is the volume of naoh is consumed at the second intersection point (l) [13]. adsorption test adsorption experiment carried out by batch technique to examine effect of contact time and ph. the other, batch technique also used to kinetic study. in here, bovine serum albumin (bsa) was selected as model protein in the present study. 3 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 effect of contact time on bsa adsorption bsa solution of 400 mg/l is added into a 100 ml erlenmeyer. then 0.1000 g of adsorbent was added [8]. the mixture is shaken with a shaker at a speed of 100 rpm to avoid protein damage [14]. shuffle is done with a time range of 60, 90, 120, 150 and 180 minutes. the suspension is filtered with filter paper. filtrate was taken 50 µl and put in a cuvette. the solution was added to 2.5 ml of bradford reagent and allowed to stand for 5 minutes. the absorbance solution was measured by a visible spectrometer at maximum wavelength [15]. effect of ph on bsa adsorption protein solution of bovine serum albumin (bsa) concentration of 400 mg/l was made by taking 20 ml of bovine serum albumin (bsa) solution of 1000 mg/l and put it in a 50 ml volumetric flask. the solution was diluted with citrate-phosphate buffer ph 3, 4, 5 and 6. bsa solution 400 mg/l from a 50 ml volumetric flask was then put into a 100 ml erlenmeyer. solution added 0.1000 g of adsorbent [8]. the mixture is shaken with a 100 rpm speed shaker to avoid protein damage [14]. shaking is done as long as the time that has been generated when there is equilibrium. the suspension is filtered with filter paper. filtered filtrate was taken 50 µl and put in a cuvette. the solution was added to 2.5 ml bradford reagent and allowed to stand for 5 minutes. the absorbance solution was measured by a visible spectrometer at maximum wavelength [15]. results and discussion functional group analysis by ftir figure 1 shows ftir-spectra for both of bc and mbc have similar bands, indicate that after acid hydrolysis treatment did not change structure on bc. broad bands at 3346 represent to oh stretching vibration, the band 2897 cm -1 to c-h stretching vibration, 1431 cm -1 to c-h bending vibration, and 1058 cm -1 to c-o-c bending vibration. figure 1. ftir spectra of bc and mbc 4 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 crystallinity by xrd and surface charge group xrd analysis was used to determine changes in the degree of crystallinity of bc after acid hydrolysis treatment. figure 2 shows that there is increasing crystallinity from 84.5% (bc) to 87.7% (mbc). increasing degrees of crystallinity due to remove amorphous region in the bc after acid hydrolysis treatment. during hydrolysis, hydrochloric acid breaks the 1.4 beta glycoside bond in the amorphous region [10]. surface charge group of mbc was determined by conductometric titration. charge group is sulfat group that attach on the bc structure. as the result, surface charge group of mbc is 9 mmol/kg. figure 2. x-ray diffraction pattern of bc and mbc effect of contact time figure 3 shows effect of contact time for protein adsorption show that adsorption equilibrium is reached within 90 minutes for both bc and mbc, and further increase of contact time, it was not change significantly. compare with bc, mbc have higher protein adsorption capacity. it can be explained that after acid hydrolysis treatment, mbc have surface charge group that play important role in increasing adsorption capacity. 5 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 figure 3. effect of time on protein adsorption effect of ph figure 4 shows that the protein adsorption capacity on both of bc and bc decreased with increasing ph. protein adsorption is highest in the ph of 3. it can be explained that ph below the isoelectric point lead to positively charge of protein that generate high interaction with mbc that have negatively charge. in the other hand, ph above the isoelectric point lead to negatively charge of protein, consequently electrostatic repulsion take place [8]. 6 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 figure 4. effect of ph on protein adsorption kinetic study in here, pseudo second order model was selected as kinetic study in this present study. pseudo second order model described binding capacity was proportional to the number of active sites occupied on the sorbent (equation 2) [16]. (2) where, k is the equilibrium rate constant of pseudo second order adsorption kinetics [g/mg min], qe the amount of metal ion adsorbed at equilibrium [mg/g], qt the amount of absorbate on the surface of sorbent at any time t [mg/g] 7 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 figure 5. pseudo second order model of protein adsorption on bc and mbc based on figure 5, the pseudo second order model is suitable for mbc but not for bc. the result of the constant values obtained is 3.03. conclusions modified bacterial cellulose (mbc) by acid hydrolysis has been successfully prepared as adsorbent for protein. compare with bacterial cellulose (bc), bc have higher in adsorption capacity. protein adsorption below the isoelectric point is higher for both of bc and mbc. it is due to electrostatic interaction between adsorbent and adsorbat. based on kinetic study using pseudo second order kinetic model, kinetic constant is 3.03. acknowledgements this research was supported by funding of ministry of research and technology, republic of indonesia 2018. references [1] p. gatenholm, and d. klemm, 2010, bacterial nanocellulose as a renewable material for biomedical applications, material research society bulletin, volume 35, page 208-213. [2] a.m.a. gallegos, s.h. carrera, r. parra, t. keshavarz, and h.m. iqbal, 2016, bacterial cellulose: a sustainable source to develop value-added products–a review, bioresources, volume 11, no. 2, page 5641-5655. 8 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 [3] c. vilela, r.j. pinto, a.r. figueiredo, c.p. neto, a.j. silvestre, and c.s. freire, 2017, development and applications of cellulose nanofibres based polymer nanocomposites, advanced composite materials: properties and applications. ed. e. bafekrpour, page 1-65. [4] mohite, v. bhavna, patil and v. satish, 2014, bacterial cellulose of gluconoacetobacter hansenii as a potential bioadsorption agent for its green environment applications, journal of biomaterials science, polymer edition, volume 25, no.18, page 2053-2065. [5] t. oshima, s. taguchi, k. ohe, and y. baba, 2011, phosphorylated bacterial cellulose for adsorption of proteins, carbohydrate polymers, volume 83, no. 2, page 953-958. [6] t. niide, h. shiraki, t. oshima, y. baba, n. kamiya, and m. goto, 2010, quaternary ammonium bacterial cellulose for adsorption of proteins, solvent extraction research and development, japan, volume17, page 73-81. [7] q. lin, y. zheng, g. wang, x. shi, t. zhang, j. yu, and j. sun, 2015, protein adsorption behaviors of carboxymethylated bacterial cellulose membranes, international journal of biological macromolecules, volume 73, page 264-269. [8] t.s. anirudhan, s.r. rejeena, & a.r. tharun, 2013, investigation of the extraction of hemoglobin by adsorption onto nanocellulose-based superabsorbent composite having carboxylate functional groups from aqueous solutions: kinetic, equilibrium, and thermodynamic profiles. industrial & engineering chemistry research, volume 52, no. 32, page 11016-11028. [9] c. chirayil, j.l. mathew, & s. thomas, 2014, review of recent research in nano cellulose preparation from different lignocellulosic fibers. reviews on advanced materials science, volume 37. [10] t. mulyono, asnawati, i. noviandri, dan buchari, 2007, potensi membran nata de coco sebagai material biosensor (the use of nata de coco membrane as biosensor material). jurnal ilmu dasar, volume 8, no.2, page 128-134. [11] y. yue, c. zhou, a. d. french, g. xia, g. han, dan q. wang, dan q. wu, 2012, comparative properties of cellulose nano-crystals from native and mercerized cotton fibers, cellulose, volume 19, no. 4, page 1173–1187. [12] m. loelovich, 2012, optimal conditions for isolation of nanocrystalline cellulose particles. nanoscience and nanotechnology, volume 2, no. 2, page 9-13. [13] a. romdhane, m. aurousseau, a. guillet, dan e. mauret, 2015, effect of ph and ionic strength on the electrical charge and particle size distribution of starch nanocrystal suspensions. starch/stärke, volume 67, issue 3-4, page 319–327. [14] b.v. mohite, dan s. v. patil, 2014, bacterial cellulose of gluconoacetobacter hanseniia as a potential bioadsorption agent for its green environment applications. journal of biomaterials science polymer edition, volume 25, no.18, page 2053-2065. 9 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 1-9 submitted : december 20, 2019 accepted : february 10, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26413 [15] m.m. bradford, 1976, a rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding, analytical biochemistry, volume 72, issue 1-2, page 248-254. [16] m. stojanović, z. lopičić, j. milojković, č. lačnjevac, m. mihajlović, m., petrović, & a. kostić, 2012, biomass waste material as potential adsorbent for sequestering pollutants. zaštita materijala, volume 53, no. 3, page 231-237. 68 computational and experimental research in materials and renewable energy(cerimre) volume3, issue2, page 68-74 eissn : 2747-173x submitted :july 21, 2020 accepted : august 20, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23547 study of vortex generator effect on airfoil aerodynamics using the computational fluids dynamics method siti aisyah ayudia 1,a , artoto arkundato 1 , and lutfi rohman 1 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no. 37, jember 68121, indonesia a sitiaisyahayudia23@gmail.com abstract. the lift force is one of the important factors in supporting the aircraft flying capabilities. the airplane has a section called the aircraft wing. in particular, the wing section of aircraft is called the airfoil. one of the efforts to increase the lift force is to make the flow of air fluid at the top of the airfoil more turbulent. turbulent flow can attract momentum from the boundary layer, the result of this momentum transfer has energy that is more resistant to the adverse pressure gradient which can trigger the flow separation. efforts that can be made to reduce separation flow and increase lift force are the addition of a turbulent generator on the upper surface of the airfoil, one type of turbulent generator is a vortex generator, a vortex generator can accelerate the transition from the laminar boundary layer to the turbulent boundary layer. this study was conducted with the aim of knowing the effect of the vortex generator on the aerodynamics of naca-4412 using the computational fluid dynamics method. the main thing that will be investigated is the effect of the straight type vortex generator application on the lift coefficient, by comparing the plain airfoil and airfoil that has been applied to the vortex generator to vary the angle of attack. the variation of the angles of attack are 0º, 5º, 10º, 15º and the placement of the vortex generator is 24% of the leading edge. the results obtained that the lift coefficient changes with increasing angle of attack and the application of a vortex generator to an airfoil can increase the lift coefficient than a plain airfoil. the optimum increase in lift coefficient is at the angle of attack of 5º as much as 13%. keywords: computational fluid dynamics, vortex generator, airfoil, angle of attack introduction various studies on aircraft parts for flight optimization were carried out. aircraft construction is generally divided into several major parts such as the wings (hereinafter referred to as airfoils), body, and tail. in particular, an airfoil is a very important part of the aircraft's flying ability. this flying ability is closely related to the ability of the aircraft's lift, which is determined by the airfoil design. there are 4 forces that are generally involved and determine aircraft performance, namely lift, drag, stall and thrust forces. the lift force plays an important role in lift for an airplane. the lift force occurs due to higher pressure on the lower surface of the airfoil and low pressure on the upper or upper surface of the airfoil. after passing the leading edge position at the front of the plane behind the air fluid flow becomes faster but after passing the top of the airfoil the flow slows down. when the flow momentum is unable to overcome the adverse pressure gradient, a separation flow occurs around the airfoil which can cause the aircraft to lose its lift force. the lift force on the airfoil is known to be influenced by the angle of attack (hereinafter written aoa) of the airfoil. airfoil has unique characteristics for each type, so proper 69 computational and experimental research in materials and renewable energy(cerimre) volume3, issue2, page 68-74 eissn : 2747-173x submitted :july 21, 2020 accepted : august 20, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23547 research is needed for the use of airfoils according to the application. currently, aircraft research uses a lot of simulation methods to determine the optimum conditions [8]. the position of aoa is very important to be studied, because when aoa is at its optimum condition, the lift force will be maximized and this has a good impact on aircraft efficiency and can delay the separation flow so that the lift force becomes even greater. too high an airfoil position can make the pressure in the upper space of the airfoil low and trigger flow separation. the existence of separation flow is very detrimental because the separation flow causes the lift force to decrease. flow separation events can occur especially when the angle of attack is high. therefore, airfoil modification must be done in various ways, for example, the most common method is to use a vortex generator. this vortex generator can be added to the airfoil which will be able to modify the separation flow so as to increase the lift force [5]. a vortex generator is an object that is used to modify the air flow around an airfoil with various specific shapes. one of them is in the form of a fin or fin which can accelerate the transition from a laminar boundary layer to a turbulent boundary layer. during the turbulent boundary layer, the velocity of the fluid closest to the surface will have a value greater than that of the boundary laminar layer. the greater the fluid velocity will have an impact on the kinetic energy of the fluid which will also increase, so that it can fight against the adverse pressure gradients [5]. the article conducts a study to determine the aerodynamic characteristics of the aircraft (wing) on plain airfoils and airfoils that are given a vortex generator. in this study, the airfoil model used was naca-4412 with a triangular vortex generator type vortex generator. this research uses naca-4412 because this model is quite popular in airplane design tutorials. the main analysis in this research is to compare the lift coefficient on plain airfoil and modified airfoils with a vortex generator. researchers used a naca-4412 airfoil and triangular type vortex generator to determine aerodynamic characteristics. aerodynamic characteristics studies with the addition of the airfoil vortex generator naca-4412 will be carried out using cfd (computational fluid dynamics) software simulation, namely solidworks. the use of solidworks in this study will be very useful for simulating aircraft fluid flow and knowing the impact that occurs by including physical variables such as angle of attack and wind speed in the simulation input. materials and methods airfoil airfoil is something that when placed in a fluid flow will produce a lift force. the lift or lift force occurs because the shape of the top of the airfoil is curved which causes the fluid to flow above the airfoil faster, when the fluid flows faster, the pressure will be lower. the fluid that flows under the airfoil has a velocity below the fluid flowing above the airfoil, because this is where the pressure below the airfoil is greater and a lift force is created [3]. two major types of airfoils are symmetrical airfoils and asymmetrical airfoils. this symmetrical airfoil has the same top and bottom shape, which causes the chamber to always have a value of 0, usually this type of airfoil is placed for the tail. symmetrical airfoil is often used as a stabilizer for aerobatics which have extreme maneuverability. asymmetrical airfoil has an upper curve more curved than the bottom curve of the airfoil surface, this type of airfoil is the most common shape of conventional aircraft [15]. 70 computational and experimental research in materials and renewable energy(cerimre) volume3, issue2, page 68-74 eissn : 2747-173x submitted :july 21, 2020 accepted : august 20, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23547 vortex generator a vortex generator is an object that is used to modify air flow by placing it on the outer surface of an object such as an airplane wing, car, windmill, or around an airfoil with various specific shapes. one of them is in the form of fins or fins. the installation of a vortex generator on the aircraft wing can make the lift on the aircraft wing more efficient, especially in large aoa before critical aoa. the vortex generator has a way of working with the system when the plane is running to break the wind in the air, the vortex generator creates a process that causes data to move from the laminar boundary layer to the turbulent boundary layer due to the transfer of momentum [3]. figure 1.type of vortex generator [7] the three major forms of vortex generators commonly used in aerodynamics, the first is the gothic vg form, the second is the vg rectangular shape, the third is the triangular vg. comparisons were made to these three types of virtual generators and the results of the analysis gave a drag value of 0.008797 for rectangular vg, 0.006990 for gothic vg, and 0.0022062 for triangular vg at aoa 0°. the triangular type vortex generator provides the best drag force reduction of the other two forms [7]. angle of attack angle of attack is the angle formed by the direction of air flowing on an airfoil and bowstring on an airfoil. aoa is usually written with the notation α. the air flow will flow on the airfoil and form a negative angle, this causes the angle of attack to have zero lift, this condition is called zero lift angle [9]. figure 2. wing cross section [8] 71 computational and experimental research in materials and renewable energy(cerimre) volume3, issue2, page 68-74 eissn : 2747-173x submitted :july 21, 2020 accepted : august 20, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23547 flow on the airfoil air flow on an airfoil is divided into three types, namely laminar flow, transition flow, and turbulent flow. liquid / gas particles in laminar flow move in a regular and parallel path. laminar flow occurs when the viscosity is large or the velocity is low [2]. figure 3. flow on the airfoil [2] fluid viscosity has a major influence in reducing disturbances that result in turbulent flow. when the viscosity decreases and there is an increase in flow velocity, the damping power to the disturbance is reduced, to some extent it can cause a change in flow, namely changing the laminar flow to turbulent flow. in the turbulent flow, the gas or liquid particles move irregularly. turbulent flow occurs when the gas or liquid is small and at high velocity [11]. cfd (computational fluid dynamic) cfd (computational fluid dynamics) is a set of methodologies used so that computers can display a numerical simulation of fluid flow. the system that occurs in cfd uses a mathematical model which is transformed into a virtual form so that it can be visualized. broadly speaking, there are three stages in the cfd simulation process [3]. the pre-processing stage is the part where the process of defining the geometry of the airfoil model will be simulated into a computational domain that can be processed by computer. create constraints for the simulation of airfoils. defining the fluid to be used and other variables: the solver stage occurs in a numerical computation process using the equations used for cfd simulations. the navier-stokes equation is the basis that is always used in cfd flow simulations. this equation is represented by the geometry formed by flow acceleration and pressure. the navier-stokes equations are always solved by the continuity equation, based on the principle of momentum, when the continuity equation represents the conservation of mass. this equation can be used for each flow point and shows all the details of the flow that can be solved in the flow area. however, many of the differential equations of fluid mechanics are too difficult to solve and require the help of computers [3]. this post-processing stage of numerical computation results is displayed and documented. this visualization is useful for analysis. in addition, you can also see the velocity contours on the airfoil [3]. formula the navier-stokes equation is the basis for almost all cfd (computational fluid dynamics) flow modeling. this equation predicts the velocity of a fluid and its pressure in a given geometry. the 72 computational and experimental research in materials and renewable energy(cerimre) volume3, issue2, page 68-74 eissn : 2747-173x submitted :july 21, 2020 accepted : august 20, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23547 navier-stokes equations are always solved together with the continuity equation. the navierstokes equation serves as a conservation of momentum, while the continuity equation represents conservation of mass. this equation is valid for any point in the flow and thus all details of the flow can be solved anywhere in the flow domain. however, most of the differential equations in fluid mechanics are very difficult to solve and therefore often require assistance from computers. this equation in certain cases may need to be combined with additional equations, such as the energy equation. navier-stokes formula shows at the equation below [6]. (1) results and discussion below is a graph table for plain airfoil and airfoil with the addition of a vortex generator for aoa variations. table 1. lift coefficient data on airfoil with vortex generator and plain airfoil angle of attack vortex generator plain airfoil lift coefficient lift coefficient 0 0.1699 0.1549 5 0.3403 0.3178 10 0.543 0.5308 15 0.7749 0.7754 figure 4. lift coefficient graph against aoa table 2. the result of the percentage difference in lift coefficient lift coefficient airfoil with vortex generator lift coefficient plain airfoil different lift coefficient percentage 0.1699 0.1549 0.015 8.83% 0.3403 0.3178 0.0225 13.24% 0.543 0.5308 0.0122 7.18% 0.7749 0.7754 0.0005 0.29% 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 0 5 10 15 li ft c o e ff ic ie n t angle of attack (°) vortex generator lift plain foil lift 73 computational and experimental research in materials and renewable energy(cerimre) volume3, issue2, page 68-74 eissn : 2747-173x submitted :july 21, 2020 accepted : august 20, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23547 the graph above shows that the use of a vortex generator can increase the lift coefficient. airfoil with aoa 5° displays a red area that is larger than at a 0° angle, this is because changes in aoa, aoa 5° are more effective in maximizing the potential of the vortex generator. momentum is drawn from the boundary layer because of the vortices caused by the application of the vortex generator, therefore the energy around the vortex generator is getting bigger and can withstand adverse pressure gradient and can delay the flow of separation which can trigger a stall. the rapid air dispersion in the upper space causes the pressure to be smaller than the lower surface. this results in an increase in lift force. the increase in lift coefficient affects the airfoil lift. a significant lift coefficient comparison between plain airfoil and airfoil with vortex generators is at an angle of attack of 5° with a difference of 13%. the behavior of the vortex generator with the specifications of the leg dimensions 0.18 cm thick, 4.5 cm wide, 10 cm long, and the fin dimensions 10 cm long, 4.5 cm high, 0.25 cm thick with straight-type arrangement is given to the naca airfoil -4412, the specification of the airfoil is 400 cm long, 200 cm wide, and the placement of the vortex generator on the airfoil is 24% of the leading edge. of course, the results obtained are relatively different if the vortex generator applied to the airfoil has different dimensions. conclusions based on the research results, it can be concluded in the form of. the increase in lift coefficient is directly proportional to the increase in angle of attack. based on the simulation results for the naca-4412 airfoil, a significant increase in lift coefficient between plain airfoil and airfoil with the vortex generator at an angle of attack of 5°. references [1] s. agarwal and p. kumar, 2015, investigation of flow field over naca 4412 with a vortex generator, adr journals 1 (4), page 1-12. [2] h. anam, l. haris, a. budiyanto and a. budiyono, 2016, design of diver propulsion vehicle ganendra ri-1 using solidworks flow simulation, marine and underwater science and technology: unsys digital [3] u. azmi and h. sasongko, 2015, studi eksperimen dan numerik penstudi eksperimen dan numerik pengaruh penambahan vortex generator pada airfoil nasa ls-0417garuh penambahan vortex generator pada airfoil nasa ls-0417, jurnal teknik its 4 (1), page b012-b017. [4] i. haryanto, m. t. s. utomo, n. sinaga, c. a. rosalia and a. p. putra, 2014, optimization of maximum lift to drag ratio on airfoil design based on artificial neural network utilizing genetic algorithm, applied mechanics and materials, volume 493, page 123-127. [5] a. jir´asek, 2005, vortex-generator model and its application to flow control, journal of aircraft 42 (6), page 1486-1490. [6] a. jonuskaite, 2017, flow simulation with solidworks, findland: arcada [7] g. v. kumar, k. s. narayanan, s. k. a. kumar and s. k. kumar, 2016, comparative analysis of various vortex generators for a naca 0012 aerofoil, international journal of innovative studies in sciences and engineering technology (ijisset) 2 (5), page 3-6. 74 computational and experimental research in materials and renewable energy(cerimre) volume3, issue2, page 68-74 eissn : 2747-173x submitted :july 21, 2020 accepted : august 20, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23547 [8] a. f. lubis and i. isranuri, 2012, analisa gaya impak yang terjadi pada badan pesawat aeromodelling tipe glider saat landing dengan variasi sudut pendaratan yang disimulasikan dengan menggunakan software solidworks, jurnal e-dinamis 1 (1), page 62-66. [9] s. moreau, 2005, effect of angle of attack and airfoil shape on turbulence-interaction noise, 11th aiaa/ceas aeroacoustics conference meeting and exhibit, page 3-7. [10] s. a. prince, v. khodagolian and c. singh, 2009, aerodynamic stall suppression on airfoil sections using passive air-jet vortex generators, aiaa journal 47 (9), page 2232-2234. [11] m. m. saleh and e. widodo, 2018, analisa kinerja aliran fluida dalam rangkaian seri dan paralel dengan penambahan tube bundle pada pompa sentrifugal, jurnal r.e.m.(rekayasa energi manufaktur) 3 (2), page 71-73. [12] r. setiawan, 2015, penjelasan pakar penerbangan soal kondisi "stall" pesawat, http://bit.do/penjelasan-pakar-penerbangan-soal-kondisi-stall-pesawat, was accessed march 11, 2020. [13] a. udris, 2015, vortex generators: preventing stalls at high and low speeds boldmethod, https://www.boldmethod.com/learn-to-fly/aerodynamics/vortex-generators/, was accessed march 13, 2020. [14] r. j. volino, 2003, separation control on low-pressure turbine airfoils using synthetic vortex generator jets, journal of turbomachinery 125: 765. [15] c. wiratama, 2016, pemilihan airfoil pesawat aeromodeling, http://aeroengineering.co.id/2016/02/pemilihan-airfoil-pesawat-aeromodelling/, was accessed march 13, 2020. http://bit.do/penjelasan-pakar-penerbangan-soal-kondisi-stall-pesawat http://www.boldmethod.com/learn-to-fly/aerodynamics/vortex-generators/ 35 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 effect of temperature on the electron concentration of crystalline gaas semiconductor based on the p-n junction due to deformation potential scattering nova alviati 1 , samsiatun hoiriyah 1 , misto 1 and edy supriyanto 1 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no. 37, jember 68121, indonesia a novaalviati11@gmail.com abstract. the electrical characteristics of semiconductor materials can be predicted based on the transport of charge carriers within the material. under room temperature, the electrical properties of semiconductor materials can be exploited by knowing the value of their electron mobility to predict the number of electrons that experience the transport mechanism. when the material is observed under room temperature, the interaction of electrons and the lattice atoms' vibrations result in deformation potential scattering. this can stimulate electron mobility changes, which can affect the number of free electrons in semiconductor materials. the research results presented in this paper simulate the number of electrons that change due to electrons' mobility in the gaas crystal. this material undergoes potential scattering deformation due to the interaction between electrons and phonons at temperature (40-100)k. the simulation is carried out by modeling the gaas semiconductor material in the form of a p-n junction. the temperature variation given to the material shows a significant change in concentration in the junction area. in contrast, in the contact area's vicinity with the external circuit, both the p-layer and the n-layer show relatively constant electron concentrations. keywords: deformation potential scattering, electron concentration, gaas, simulation, electron mobility introduction gaas semiconductor crystal is an alloy semiconductor material composed of gallium (ga) and arsenic (as). at room temperature, this material has an energy band gap of 1.43 ev with a direct bandgap energy band structure [1]. this energy band gap is more expansive than si, so this material is better for the manufacture of electronic devices that can operate up to highfrequency regions [2]. in general, all electronic devices are designed to operate at room temperature (300k). theoretically, above a temperature of 0k, the atoms of semiconductor materials experience lattice vibrations that interfere with electrons' free movement in the material. the interaction between electrons and vibrating lattice atoms gives rise to a scattering phenomenon in a semiconductor known as phonon/lattice scattering [3]. one type of phonon scattering that occurs in gaas semiconductor crystal material is deformation potential scattering. the deformation potential scattering event causes periodic changes in the distance between lattice points on the atoms of the crystal [4]. the dependence of electron mobility on temperature due to the deformation potential scattering effect is mathematically expressed by the following equation [5]: 36 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 μn≈t −3/2 (1) the parameter μn is the mobility of the electron, and t is the temperature. this scattering phenomenon can affect the distribution of electron concentrations in the material. therefore, it is necessary to conduct research studies to find out how much influence is generated. the study can explain the gaas semiconductor material's electrical characteristics, mainly due to the deformation potential scattering. furthermore, the value of the electron concentration obtained is plotted according to temperature variations so that the n-t characteristic curve is obtained due to the deformation potential scattering event. materials and methods this research was conducted by applying the finite element method. gaas semiconductor crystal material is modeled into 2-dimensional cross-sections and divides the area into small triangular elements with the non-linear distribution of electric fields and charge carriers. the partial differential equation of the gaas semiconductor is applied to the geometry by applying several material boundary conditions. each element's solution is the concentration of electrons as free charge carriers in the device being modeled. the calculation of electron concentration due to the deformation potential scattering phenomenon was carried out at 40k, 60k, 80k, and 100k. the input of the value of electron mobility for each temperature was (3 x 10 14 μm 2 /vs), (1.5 x 10 14 μm 2 /vs), (9 x 10 13 μm 2 /vs) and (7 x 10 13 μm 2 /vs). as control data, simulations were carried out at a temperature of 300k with an electron mobility value of (8500 x 10 8 ) μm 2 /vs. stages of the simulation process carried out from entering the input data; include gaas semiconductor crystal geometry (figure 1), gaas semiconductor crystal parameters [6,7], and boundary condition setting [8], which was applied to the fourth boundaries in figure 1. positions 2 and 3 are the boundary lines between the device and metal contacts. here, the dirichlet conditions are imposed at the metal– semiconductor surfaces. otherwise, the neumann condition have applied for positions 1 and 4, we have applied neumann condition as the boundary condition. the final simulation process was to solve the poisson and continuity equations of the electrons. 37 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 figure 1. gaas semiconductor crystal geometry which has been divided into triangular-shaped elements the results obtained from the simulation process are the distribution of electron concentrations in all areas of the device being modeled. the electron concentrations at several observation points are analyzed. the observation areas include: anode area a (0.0725; -0.00629), the area near anode b (0.26; -0.2), the p layer area near the joint, namely point c (0.0642; -0.326) and d (0.366; -0.345), the n layer area near the joint, namely e (0.155; -0.357) and f (0.366; -0.37), the area near the cathode g (0.26; -0.502) and cathode area h (0.366; -0.694). the temperature variations were applied to the device model, and the effect on the concentration of electrons in the material had been analyzed. results and discussion electron concentration distribution in deformation potential scattering phenomenon in gaas semiconductor crystal the results of modeling the gaas semiconductor crystal material from this study describe a 2dimensional profile of the electron concentration distribution and the number of electron concentrations in the material. the distribution of electrons in the p-n junction device is visually shown in figure 2, while the number of electron concentrations can be seen in table 1. 38 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 table 1. electron concentration at t=40 k and μ n ( ) μm position coordinate electron concentration (µm -1 ) a (0.07250;-0.00629) 1.326 x 10 2 b (0.26000;-0.20000) 1.649 x 10 2 c (0.06420;-0.32600) 2.510 x 10 7 d (0.36600;-0.34500) 6.758 x 10 8 e (0.15500;-0.35700) 11.879 x 10 11 f (0.36600;-0.37000) 15.096 x 10 14 g (0.26000;-0.50200) 16.264 x 10 16 h (0.36600;-0.69400) 16.582 x 10 16 figure 2. modeling results of electron concentration distribution at t = 40 k in the event of potential deformation scattering with each color on the right side representing the scale of the electron concentration value, which is 10 to the power of numbers each color index 39 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 figure 2 shows that the amount of electron concentration at a 40k temperature depends on each color that appears. each color represents a scale, which is the power index of the number 10. at point a, the concentration of electrons has the order 10 2 m -1 . number 2 in the upper index of number 10 is represented in blue. at temperatures of 60k, 80k and 100k, the simulation results show a similar image to the state at 40k. however, numerically, the electron concentration at each point of the observation area is not the same for these temperature variations. the simulation results show that the closer to the cathode (negative pole), the greater the electrons' number, which is indicated by the higher electron concentration. these results are consistent with the theory that the highest number of electrons is in the negative pole [9]. the simulation results of the gaas semiconductor crystal material shown in figure 2 provide information on the presence of two dominant colors in the material, separated from each other. the color contrast of the two is quite large, which means a difference in the amount of concentration in the two areas. dark red represents the maximum electron concentration scale, and dark blue represents the minimum electron concentration scale. these results can be analyzed based on the types of atomic bonds in the gaas semiconductor crystal material, a 2element semiconductor alloy whose atomic bonds consist of mostly covalent bonds and a small portion of ionic bonds [10]. the character of ionic bonds in the material causes the oscillation of ions in the gaas semiconductor crystal material when given a temperature so that a dipole moment is formed per volume unit, which is called polarization [11]. the polarization event causes a difference in the concentration of electrons in the geometry of the material so that there is a part of the geometry that has a maximum electron concentration (dark red) and a part of the geometry that has a minimum electron concentration (dark blue). the contrasting color difference based on the electron concentration value between the two regions in the gaas material causes the formation of a central region that limits the two dominant regions in the material's geometry. the middle area in the geometry of the material is almost similar to the depletion region in the p-n diode junction, which is analyzed as the separation region between positive atoms (low electron concentration) and negative atoms (high electron concentration) in gaas semiconductor crystal material which has ionic bond characteristics [10]. at all temperatures, namely 40k, 60k, 80k and 100k, there was a change in the width of the central region of the gaas semiconductor crystal geometry (similar to the depletion area), namely the width re pectively at the temperature variation of . μm, . 6 μm, . 8 μm and .5 μm, namely at the po ition of region c to region f. the change in the middle area (region c to region f) i relatively mall, with a range of . μm at any given temperature variation. this occur because, at shallow temperatures (<200k), the lattice vibration energy of the crystal is not sufficient to ionize all electrons in the material, so that the change in the value of the electron concentration is not too large, which is indicated by a relatively small change in the width of the color area [13]. however, the event being studied is the deformation potential scattering, which is focused on the phenomenon of electron-phonon interaction so that what is reviewed is the scattering effect that occurs in the material. increasing the temperature above 0k triggers lattice vibrations, causing the scattering in the material to intensify, affecting the flow of electrons from the cathode to the anode (electron diffusion current). therefore, based on the numerical results, it is informed that simultaneously when the temperature in the material increases, the value of the electron concentration in the e and f regions decreases while the electron concentration 40 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 values in the c and d regions increase, thus indicating the occurrence of electron diffusion currents in regions the material. the simulation of the distribution of electron concentration values at 300k (room temperature) was carried out as a control value in this study. this is understandable because the temperature of 300k is the operating temperature of the semiconductor material; most electronic devices are designed to operate at this temperature. in general, the analysis is understood qualitatively in the semiconductor material that the value of the electron concentration in the semiconductor material will increase along with the increase in the value of temperature given to the material [12]. for this reason, the simulation results at a temperature of 300k are used as the benchmark value of the simulation results that have been carried out at temperatures of 40k, 60k, 80k and 100k. at this temperature, there is a change in the width of the central part of the geometry (region c to where f) i .66 μm in width. by the theory that if the temperature (> 200k), then the lattice vibrational energy is sufficient to ionize all electrons in the semiconductor material [13]. this results in the dark red area (region g and region h) getting narrower, which indicates an electron diffusion current. this phenomenon indicates that the electrons in these regions have ionized and flowed towards the areas above them (region d and region e). however, an increase in temperature also increases the number of electrons so that electrons' mobility is reduced, which is measured from the smaller electron mobility parameter. this causes the movement of electrons to become slower as the temperature in the material increases. this slower movement of electrons disrupts the process of electron diffusion towards the anode, as a result of which the electrons gather in the central region of the geometry of the material (region c, region d, region e, and region f). therefore, at a temperature of 300k, the increase in the width of the central area of the gaas semiconductor crystal geometry is more significant than the previous temperatures because more electrons are ionized from the material. characteristics curve of n-t gaas semiconductor crystals due to temperature variations in deformation potential scattering process the change in the value of the electron concentration due to the increase in temperature applied to the gaas semiconductor crystal material causes different effects in each region in the material model's geometry. for this reason, the n-t characteristic curve is made so that the examination of the relationship between the electron concentration value and temperature can be easier to see and analyze. the results of the n-t characteristic curve in the deformation potential scattering are shown in figure 3. the characteristic n-t curves shown in figure 3 and figure 4 represent the change of electron number for all regions in the gaas semiconductor crystal material geometry. in special case, the electron concentration at position a of figure 3a (close to anode) and h of figure 4b (close to cathode), the result peformed that the increasing temperature from 20k to 100k did not alter the number of the electron concentration. therefore, the pattern of the n -t characteristic curve is constant. this is because the temperature given is relatively low while the voltage is constant so that in this region, a quasi-neutral state occurs with an indication of the number of electrons being fixed. 41 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 (a) (b) figure 3. the curve of electron concentration as function of temperature at point a, and b (a) and also for point c, and d (b) 42 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 (c) (d) figure 4.the curve of electron concentration as function of temperature at point e, and f (a) and also for point g, and h (b) furthermore, for the central region (point c and d), the result performed that the greater the temperature applied to the gaas semiconductor crystal, the greater the value of the electron concentration obtained. there is an increase in the number of electron concentration from c to d point. conversely, in the e region, there is a tendency that increasing the temperature given to the material, the value of the electron concentration decreases. this result is opposite to the 43 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 d region. this phenomenon occurs due to an electron diffusion current so that the electrons tend to flow from the e region to the d region. the value of the electron concentration in the e region have also decreased with increasing temperature. conclusions based on the discussion results, the simulation results in the phenomenon of deformation potential scattering for all temperature variations given to the gaas semiconductor crystal represent different electron concentration. the closer to the cathode, the greater the value of the electron concentration. furthermore, the central region of the material's geometry, similar to the depletion region, tends to have a different area width when given temperature variations. increasing the temperature from 40k to 100k resulted in a change in the width of the depletionlike area of . 6 μm. the number of electron concentration around the middle area perform significant change due to the increasing of temperature. a constant state occurs in the anode region, near the anode, cathode and near the cathode. references [1] l fuller, 2001, gallium arsenide device, technologies & integrated circuits, http://people.rit.edu/ lffeee/gaas.pdf. [2] sutrisno, 1986, elektronika i teori dasar dan penerapannya, institut teknologi bandung, bandung, indonesia. [3] a subekti, 2003, diktat kuliah semikonduktor, fmipa universitas jember, jember, indonesia. [4] k seeger, 1989, semiconductor physics an introduction, springer-verlag, usa. [5] s j manion, 1988, acoustic phonon scattering in modulation doped aluminumx gallium1xarsenide / gallium arsenide heterojunctions, ada 198 512, thesis, university of illinois, urbana-champaign. [6] s singhal, a k saxena, and s dasgupta, 2007, estimation of various scattering parameters and 2-deg mobilities from electron mobility calculations in the three conduction bands г, l dan x of gallium arsenida, pramana-journal of physics: indian academy of sciences, volume 69, page 687-692. [7] d rusdiana, l hasanah, and e suhendi, 2010, mekanisme hamburan defek statis dan vibrasi termal terhadap mobilitas elektron pada film tipis gan, berkala fisika issn: 14109662, volume 13 no. 1, page 39-44. [8] alviati, n. 2015. simulasi distribusi konsentrasi elektron kristal semikonduktor gaas pada peristiwa deformation potential scattering berbasis metode elemen hingga. skripsi, universitas jember. jember. [9] f h mitchell, 1959, fundamentals of electronics. london: addison-wesley publishing company, inc. [10] m fukuda, 1999, optical semiconductor devices, canada: john wiley & sons, inc. [11] k seeger, 1989, semiconductor physics an introduction, usa : springer-verlag. 44 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 35 – 44 submitted : february 1, 2019 accepted : march 28, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20560 [12]r k puri and v k babbar, 2001, solid state physics & electronics, new delhi: s. chand & company ltd. [13] a subekti, 2001, semikonduktor (tipe, energi gap dan statistik), fmipa universitas jember, jember, indonesia. 27 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 study of j-v characteristics of microcrystalline silicon solar cell on the structure of p-i-n homojunction yuningtyas nely kusuma dewi 1 , endhah purwandari 2,a , khoirul anwar 2 , misto 2 1 department of physics, faculty of science and data analytics, institut teknologi sepuluh nopember, surabaya 60111, east java, indonesia 2 departmen of physics, faculty of mathematics and natural sciences, universitas jember, jember 68121, east java, indonesia a endhah.fmipa@unej.ac.id abstract. microcrystalline silicon (μc-si) is a silicon semiconductor material with a crystalline structure in the amorphous phase. here, the transport phenomenon in this phase has been modeled to produce charge carrier distribution profile and current density-voltage characteristics. the calculations were obtained by solving poisson and continuity equations on crystal and amorphous materials which are modeled in one-dimensional p-i-n homojunction, using finite element method. the simulation results of the charge carrier distribution profile show that the highest electron concentration in the n-layer of 10 18 cm -1 , and the highest hole concentration in the p-layer of 10 18 cm -1 . the result current density-voltage (jv) characteristics curve show that the open circuitt voltage of 0,6 volts and short-circuit current density of 26.4 ma/cm. the energy conversion efficiency of 9.02% with a fill factor of 0.569. keywords: silicon, solar cell, amorphous, microcrystalline, polycrystal, monocrystal, short circuit current density, open voltage introduction a solar cell is a device that converts solar energy into electrical energy directly. solar cells are made of semiconductor material from the result of covalent bonding between material elements. one example of semiconductor materials that have been applied as production materials for transistor electronic devices, diodes, and solar cells is silicon [1]. silicon is one of the basic semiconductor materials of iv groups which is composed of atoms with a specific structure. as material from solar cell devices, silicon can be used to some structures, that is amorphous, microcrystal, polycrystal, and monocrystal. microcrystal silicon (μc-si) is a silicon semiconductor material with a crystalline structure in the amorphous phase [2]. in 2004, klein et al. reported the results of experiments on the growth microcrystal silicon solar cell with hot wire chemical vapor deposition (hwcvd) techniques with a conversion efficiency of 9.4%, open-circuit voltage of 0.58 v, and short circuit current density of 23.3 ma/cm 2 [3]. to support the research without a large cost, a simulation of hydrogenated microcrystal silicon (μc-si: h) solar cell which has been done by lin et al. in 2013 used the centaurus tcad simulator [4]. that simulation conversion efficiency of 9.7%, the open-circuit voltage of 0.523 v, and short circuit current density of 26.8 ma/cm 2 [5]. the effect of i-layer thickness on the characteristics of current-voltage in p-i-n junction of silicon crystalline based solar cell has been reported by herawati [5]. in 2016, sholeha has modeled the transport phenomena in hydrogenated amorphous silicon (a-si: h) solar cell devices by mailto:endhah.fmipa@unej.ac.id 28 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 modifying the herawati’s result [6]. in this study, a simulation of hydrogenated microcrystal silicon (μc-si: h) solar cell on p-i-n homojunction structure has performed the charge carrier distribution profile and current density-voltage (j-v) characteristics by combining amorphous and crystalline material modeling. to find out the results of modeling the device of solar cell based on hydrogenated microcrystal silicon (μc-si:h) on p-i-n homojunction structure, the finite element method had been applied. the finite element method is a method that can be used to modify according to the geometric structure simulated. materials and methods the geometry of the simulated solar cell device is in the form of a p-i-n junction. the thickness of layer p, layer i, and layer n are 0.015 m, 0.550 m, and 0.300 m, respectively [6]. figure 1 shows the geometry of solar cells in a one-dimensional structure. figure 1. the geometry of hydrogenated microcrystalline silicon (μc-si: h) solar cell device on p-i-n junction 1d. the first equation which used to determine the charge carrier distribution of solar cell based of hydrogenated microcrystal silicon (μc-si: h) is the poisson equation, as mention in equation 1 [7]. 29 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 ⃗ ( ) * ( ) , ( ) ( ) ( ) ,( ) ( ) -+ * ( ) ,( ) ( ) ( ) ,( ) ( ) -+ the second equation which used the charge carrier distribution (electron-hole) is continuity equation. continuity equations for the charge carrier distribution of electron and hole, each written in equations 2 and equations 3 [7], *( ) , ( ) ( ) ( ) ( ) , ( ) ( ) ( ) ( ) -+ 30 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 *( ) , ( ) ( ) ( ) ( ) , ( ) ( ) ( ) ( ) -+ the variables used as input parameters based on poisson and continuity equations are given in table 1. the input parameters in the simulation of solar cell based on microcrystal silicon hydrogenated (μc-si: h) used c-si and a-si: h parameters. table 1. input parameter parameter value electrical charge ( ) [8] permittivity in vacuum ( ) [8] temperature (t) [8] boltzmann constant (k) relative permittivity of material ( ) [8] photon flux ( ) [9] transmission factor (p) [7] light absorption coefficient (α) a-si:h [10] light absorption coefficient (α) c-si [11] charge carrier concentration ( ) [8] donor concentration ( ) a-si:h [12] acceptor concentration ( ) a-si:h [12] donor concentration ( ) c-si [12] acceptor concentration ( ) c-si [12] electron diffusion ( ) a-si:h [7] hole diffusion ( ) a-si:h [7] electron diffusion ( ) c-si [8] hole diffusion ( ) c-si [8] ratio between charge and neutral (c) [9] electron mobility ( ) a-si:h [7] hole mobility ( ) a-si:h [7] electron mobility ( ) c-si [7] 31 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 parameter value hole mobility ( ) c-si [7] electron life time ( ) [12] hole life time ( ) [12] minimum energy density in donor and acceptor ( ) [13] donor energy ( ) [7] acceptor energy ( ) [7] minimum energy of conduction band ( ) [7] gap energy in p-type ( ) µc-si:h [14] gap energy in i-type ( ) µc-si:h [14] gap energy in n-type ( ) µc-si:h [15] energy in the valence band ( ) [4] cross-section of the catcher at thermal velocity [7] mesh the microcrystal silicon films have been divided into 4 regions (figure 1). the division of region in the microcrystal silicon films has been two types of boundary conditions, namely dirichlet and neumann. dirichlet boundary conditions are using to describe the electric potential and charge carrier concentration. the charge carrier concentration device gives rise to the electric potential of the same magnitude as the outgoing voltage coupled with energy changes throughout the device. the electric potential and charge carrier concentration (electron-hole) are written in equations 4, 5, 6 [16]. ( √( ) ) (4) √( ) (5) √( ) (6) while the boundary region is not related to the conductor (metal), it can be explained using neumann boundary conditions, as written in equations (7), (8), and (9) [16] ̂ (7) ̂ (8) ̂ (9) 32 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 results and discussion the simulation obtained charge carrier distribution and current density-voltage (j-v) characteristics from solar cell devices based of hydrogenated microcrystal silicon (μc-si: h) on p-i-n junction with a thickness of 150å / 5500å / 300å respectively. the result of the charge carrier distribution profile is shown in figure 2 and figure 3. figure 2. one dimensional simulation of the electron concentration profile of hydrogenated microcrystal silicon(μc-si: h) solar cell on p-i-n homojunction structure with a thickness of 150å/ 5500å/ 300å and output voltage of 0 volts in figure 2, the profile of electron concentration performs that the lowest number of the electron concentration is at the end of the p-layer, indicated by a dark blue indicator located at 10 4 cm -1 . the concentration of electrons in the i-layer is relatively constant of 10 11 cm -1 indicated by a green indicator. meanwhile, the highest electron concentration is the maximum concentration of donor atoms located at the end of the n-layer connected to the metal contacts indicated by a deep red indicator of 10 18 cm -1 . 33 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 figure 3. one dimensional simulation of the hole concentration profile of hydrogenated microcrystal silicon (μc-si: h) solar cell devices on p-i-n homojunction structure with a thickness of 150å/ 5500å/ 300å and output voltage of 0 volts in figure 3, it can be obtained that the highest hole concentration in the p-layer is close to the anode indicated by a deep red indicator of 10 18 cm -1 . the highest hole concentration is the maximum concentration of the n acceptor atom. at i-layer, the concentration of the hole load carrier is relatively constant of 10 12 cm -1 . then for the n-layer, there is a decrease drastically in hole concentration until it reaches the lowest hole concentration at the end of the n-layer of 10 2 cm -1 . the majority of electron concentrations in the n-layer, while the concentration of the majority of holes lies in the p-layer. the distribution profile of the carrier concentration produced is further used to describe the current density-voltage (j-v) characteristics of solar cell devices. figure 4 show the simulation results of current-voltage (j-v) characteristics of μc-si: h solar cell on p-i-n junction with a coating thickness of 150å/ 5500å/ 300å respectively. 34 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 figure 4. j-v characteristics curve of a μc-si: h solar cell devices on p-i-n homojunction structure with a thickness of 150å/ 5500å/ 300å, where the shaded area indicates the maximum area used in the calculation of device output power figure 4. indicates that the open-circuit voltage (v) of the simulation result is 0.6 volts, and short circuit current (j) of 26.4 ma/cm. a comparison of the current density-voltage (j-v) characteristics curve from the simulation results in this study, klein's experiments [3], and lin's simulations [4] is shown in figure 5. figure 5. the current density-voltage (j-v) characteristics of hydrogenated microcrystal silicon (μc-si: h) solar cell by lin’s simulation, klein’s experiment, and simulation in this study 35 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 the simulation of current density-voltage (j-v) characteristics curve of this study occurred changes in current tightness significantly not as sharp as klein’s experiments. the tight circuit of the klein’s experiment (j-v) was relatively stable for the current-density value at a voltage of 00.4 volts. while at a voltage of 0.4-0.58 volts, the change in current tightness decreases drastically. the change in the current-density is insignificant. the result of current density-voltage (j-v) characteristics curve on this simulation is not as sharp as the lin's simulation and decreases in current value significantly. lin's simulation current density-voltage (j-v) characteristics curve is relatively stable for current tight values at voltages of 00.4 volts. while at a voltage of 0.4-0.53 volts, the change in current tightness decreases drastically. the addition of equations for crystal-structured semiconductor materials in an amorphous structure, semiconductor materials can affect the tight current density-voltage (j-v) characteristics. figure 6. indicated the difference in the results of the calculation of electrical current-density between the modeling of amorphous and microcrystal materials. figure 6. the current density-voltage (j-v) characteristics curve of hydrogenated microcrystal silicon (μc-si: h) solar cell conducted in simulation (in this study) and sholeha simulation using hydrogenated amorphous silicon (a-si: h) solar cell the simulation results by sholeha using a hydrogenated amorphous silicon device (a-si: h) solar cell in the p and i layers and using a hydrogenated microcrystal silicon solar cell device in the n-layer is resulting circuit open voltage of 0.8 volts and a short circuit current of 15.61 36 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 ma/cm [6]. while the current density in this study of 26.4 ma/cm. by adding semiconductor equations for crystal materials to semiconductor equations for amorphous materials, it can increase the electrical current-density devices by 69%. the energy conversion efficiency is a reference to the magnitude of the performance of solar cell devices. the amount of calculation of conversion efficiency of hydrogenated microcrystal silicon (μc-si: h) solar cell on p-i-n homojunction structure obtained in this study of 9.02 %. conclusions the conclusion of this study that the charge carrier distribution profile of hydrogenated microcrystal silicon (μc-si: h) solar cell devices on p-i-n homojunction structure with a thickness of 150å/ 55 00å/ 300å is the highest charger carrier concentration of electron in the n-layer of 10 18 cm -1 and the highest charger carrier concentration of hole in the p-layer of 10 18 cm -1 . the current density-voltage (j-v) characteristics curve obtained an open-circuit voltage up to 0.6 volts. while the close the short circuit current of 26.4 ma/cm. in addition, the energy conversion efficiency of 9.02% with a fill factor of 0.569. references [1] s.v. litvinenko, a. v. kozinetz, dan v. a. skryshevsky, 2015, concept of transducer on a base of modified p-n junction solar cell. institute of high technologies, science direct, kyiv 01601: ukraine. [2] s. veprek, dan v. marecek. 1968, the preparation of thin layers of ge and si by chemical hydrogen plasma transport, solid state electron, volume 11, page 683-684. [3] s. klein, t. repmann, dan t. brammer, 2004, microcrystalline silicon films and solar cells deposited by pecvd and hwcvd, solar energy, volume 77, issue 6, page 893908. [4] c. h. lin, t. h. wen, dan h. t. cheng, 2013, single grain boundary modeling and design of microcrystalline si solar cells, materials, volume 6, page 291298. [5] y. herawati, 2014, the effect of thickness i-layer on calculation of current-voltage characteristics solar cells pin using finite element method, skripsi, jember: fmipa university of jember. [6] a.d. sholeha, 2016, investigation of the charge carrier diffusion coefficient in simulation of energy conversion efficiency solar cell based on a-si:h, skripsi, jember: fmipa, universitas jember. [7] i. usman, 2006, the growth of thin films of hydrogenated amorphous silicon using hwc-vhf-pecvd technique and the application of solar cell. unpublished. dissertation. bandung: itb. 37 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 27-37 submitted : january 25, 2020 accepted : april 5, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26416 [8] e. danielsson, 2000, femlab model library for semiconductor device model, stockholm: the royal institute of institute. [9] e. purwandari, and t. winata, 2013, efficiency calculation analysis of a-si:h solar cells for determination of optimum filament temperature in material deposition, jurnal ilmu dasar, volume 14, no. 1, page 29-32 [10] m.a. nigro, f. cantore , f.g. della corte, c. summonte, 2003, amorphous silicon thin film for all-optical micro modulator, proceeding of spie. 5116. [11] d. corrine, 2003. thin film microcrystalline silicon layers and solar cells: microstructure and electrical performances, thesis, swiss : institut de microtechnique. [12] c.v. sanchez, 2001, thin film nanocrystalline silicon solar cell by hot-wire cvd. barcelona: department de fisica aplicada i optica. [13] k. takahashi, and m. konagai, 1986, amorphous silicon solar cells, london: north oxford academic pub. ltd. [14] d.m. jasruddin, and a. momang, 2009. development of hydrogenated amorphous silicon solar cell p-i-n in double pecvd reactor. physics application journal, volume 5, no.1, page 14-21. [15] s. schicho, 2010, amorphous and microcrystalline silicon applied in very thin tandem solar cells, germany: institut für energieund klimaforschung. [16] m. hack, and m. shur, 1985, physics of amorphous silicon alloy p-i-n solar cells, journal of applied physics, volume 58, no. 2, page 997-1020. 1 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 study of phenomenon stt (spin transfer torque) on permalloy nife material shaped nanowire using micromagnetic simulation khiptiatun ni’mah 1 , lutfi rohman 1,a and endhah purwandari 1 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no. 37, jember 68121, indonesia a el_rahman.fmipa@unej.ac.id abstract. stt is a process of controlling the spin currents in spintronic. this simulation aims to know the properties of nife permalloy materials' properties by studying stt phenomenon-shaped nanowire that can be applied in storage devices, like mram. the material's magnetic properties include magnetization value, energy in the ferromagnetic system, and the speed of the domain wall movement, obtained by injecting the electric current density through a micro magnetic simulation using the nmag program. this simulation's result is that the domain wall's position will shift faster along the nanowire when we inject current density to the nanowire. current density injection will produce a domain wall pressure on the domain structure, resulting in a change in the material's magnetization value. the graph of magnetization relation to time (m-t), shown along with the increasing electric current density, we obtain oscillation magnetization change will increase. the larger the given diameter, the total energy generated will increase, demagnetization energy tends to be greater than the energy exchange. the greater the polarization of the material provided at the same diameter, the speed of the domain wall movement will be greater too. keywords: spintronic, stt, permalloy nife, material polarization, domain wall speed, magnetization introduction spintronic is a device that works by exploiting changes in the electron spin configuration to control the movement of charge carriers [1]. the advantages of spintronic are its fast data processing capability, smaller device size, and low energy consumption [2]. one of the potential materials for this spintronic device application is a ferromagnetic material. the ferromagnetic materials have spontaneous magnetization or what is commonly known as a magnetic domain [3]. ni80fe20 ferromagnetic material or permalloy material is a magnetic alloy material or metal alloy material composed of 80% nickel and 20% iron. permalloys with a higher nickel content than iron tend to have greater permeability than low nickel permalloys. permalloys are sensitive to impact, and their magnetism is strongly influenced by pressure [4]. research on thin films' magnetic properties and magnetic domain-walls in ferromagnetic materials has attracted scientists' attention in the last two decades. that is because these studies have the potential for data storage media based on magnets (magnetic memory devices) and magnetic sensors that carry out by utilizing the configuration of magnetic moments in the magnetic domain (magnetic domain) and magnetic domain wall (magnetic domain wall). [2]. in general, magnetic domain research can divide into two parts: research related to the magnetic domain structure and the domain-wall dynamics in nanowire-shaped ferromagnetic materials. applying an external magnetic field [5] or injection of a current polarized (current polarized) known as the stt (spin transfer torque) [6]. 2 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 theoretical background stt is a process of controlling spin currents in the spintronics field [2]. the ferromagnetic material injected with the current will change the spin direction orientation known as spin transfer torque. it will move the domain walls accompanied by a change in spin direction [7]. movement of the walls domain in the direction of current flow can generate when the current polarizes the spins. the application of this current can produce pressure in the domain's walls in an electron flow direction. the domain's wall pressure will make a magnetization change as the current density increases [8]. the dynamic in spin orientation is of particular interest in the development of magnetic storage devices. stt can generate when the material is injected with an electric current to change the spin orientation at the electron magnetic dipole moment [9]. materials and methods this micromagnetic simulation program uses the finite element (nmag) method. nmag is an open-source program that in the linux operating system. the program has a python script (.py), an input containing material parameters executed in the linux terminal. the basic concept of the finite element method is to solve a problem by dividing the object of analysis into finite small parts. these little pieces are then analyzed, and the results are recombined to find a solution for the whole area. the use of this finite element method can solve llg problems f rom a system by converting it to a discrete system so that it is possible to solve it numerically. this micromagnetic simulation is run based on the llg equation as follows: ( ) (1) the variation of the electric current density represented in this simulation is 5x10 10 , 10x10 10 , 15x10 10 , 20x10 10 a/m 2 . nanowire diameter variations to be simulated are 10 nm and 20 nm. the variation of the polarization of the material given is equal to 0.5 and 1. the table shows the input data used in the micromagnetic simulation of the nife permalloy material table 1. the data includes ms (saturation magnetization), k (anisotropy constant), a (exchange constant), and damping constant. table 1. parameter of nife permalloy material ms (a/m) k (j/m) a (j/m 3 ) damping constant 800 x 10 3 5 x 10 3 1,3 x 10 -11 0,5 the parameters which have to enter into the script file are (.geo), which contains the diameter and length of the nanowire, and (.py), which is a variation of the electric current density injection and a variation of polarization material. the next step is simulating linux terminal. the simulation results are in the form of numerical data consisting of files (.ndt) and (.vtk), which will be used in the visualization stage. visualization of domain images is done using mayavi software through files (.vtk). the next step is to create a graph plotted from the file (.ndt) using the origin software for each parameter that has been varied. the visualization and graph plot results will later be used for the analysis or interpretation of the results. after the analysis (images, charts, and tables) is carried out, a conclusion will be obtained, indicating that this research has been completed. 3 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 results and discussion the effect of injection electric current density variations on the magnetization of nanowire-shaped nife permalloy materials on the stt (spin transfer torque) phenomenon observation of the stt phenomenon due to the effect of electric current density injection on the magnetization of materials is carried out in three stages, namely observing the position of the domain wall, the structure of the domain wall due to the injection of electric current density in each nanowire diameter and the polarization of different materials and analyzing the g raph of the relationship between magnetization and time (m-t). the first stage in studying the stt phenomenon is observing the domain wall's position due to variations in electric current density. the position of the domain wall was observed by visualization. the result of isometric direction to nanowire length 100 mm, diameter 10 nm, and 20 mm was injected by an electric current density of 5x,10 10 , 10x10 10 , 15x10 10 , and 20x10 10 a/ m2 when t= 6 ns shown in figures 1 and 2. (a) (b) (c) (d) figure 1. the shift in the position of the domain walls in the material permalloy nife with current density variations 5x10 10 , 10x10 10 , 15x10 10 , and 20x10 10 a/m 2 when the polarization of the material is 1 4 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 diameter 10 nm diameter 20 nm (a) (b) (c) (d) figure 2. the shift in the position of the domain wall in the nife permalloy material with current density variations of 5x10 10 , 10x10 10 , 15x10 10 , and 20x10 10 a/m 2 when the polarization of the material is 0.5 figures 1 and 2 represent the position shift in the domain wall due to the influence of the variation of the electric current density injection in the nife permalloy material in the form of a nanowire when t = 6 ns. based on figure 4.1, with a material polarization of 1 a t 10 nm and 20 nm in diameter, when the injected electric current density increases, the position of the domain wall will shift faster to reach the end of the nanowire so that the magnetization process that occurs in the nanowire will be faster. in this case, the magnetization value is indicated by the color index on the magnetization scale (m_nife <1>). under the previous study, which gives the more significant the electric current density, the magnetization process's faster will be [3]. the next stt phenomenon study observes the magnetic domain structure due to the injection of electric current density at each different diameter and polarization of materials. the change in the color index of the domain structure represents the scale of the magnetization value. based on the domain wall's movement with a vortex structure that moves and rotates along the x-axis in the nanowire, the observed domain structure on the z-axis in each variation of the injection electric current density at t = 6 ns can be seen in figures 3 and 4. 5 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 (a) d = 10 nm d = 20 nm (b) d = 10 nm d = 20 nm (c) d = 10 nm d = 20 nm (d) d = 10 nm d = 20 nm figure 3. domain wall structure on the z-axis in permalloy nife material with density variation current 5x10 10 , 10x10 10 , 15x10 10 , and 20x10 10 a/m 2 when polarizing the material 1 (a) d = 10 nm d = 20 nm (b) d = 10 nm d = 20 nm (c) d = 10 nm d = 20 nm (d) d = 10 nm d = 20 nm figure 4. domain wall structure on the z-axis in permalloynife material with density variations currents 5x10 10 , 10x10 10 , 15x10 10 , and 20x10 10 a/m 2 when polarizing the material is 0.5 based on figures 3 and 4, we can see the increase of the injected electric current density, and the polarization of the material current density can put pressure in the wall domain. the domain wall pressure in the domain structure can result in a change in the magnetization value. we can see in the domain wall structure whose magnetic value varies with each electric current density variation. the difference in the color index of the domain structure represents the scale of the magnetization value. a graph of magnetization supports the magnetization value change to time (m-t). 6 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 current 5e10 current 10e10 current 15e10 current 20e10 (a) (b) figure 5. graph of magnetization against time (m-t) for variations in electric current density on the polarization of material 1 with a nanowire diameter (a) 10 nm (b) 20 nm current 5e10 current 10e10 current 15e10 current 20e10 (a) (b) figure 6. graph of magnetization against time (m-t) for variations in electric current density on the polarization of material 0.5 with a nanowire diameter (a) 10 nm (b) 20 nm the magnetization value of the material will change with the injection of the electric current density. the change in the value of the magnetization of the material obtained is uncertain. 7 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 based on the magnetization graph in figure 5 (a), the 10 nm diameter of the oscillation is the tightest shown at the current density of 20 x 10 10 a/m 2 in blue, while in figure (b), the diameter of 20 nm is the densest oscillation at a current density of 5 x 10 10 a/m 2 with black. the magnetization graph in figure 6 (a) is 10 nm in diameter and 20 nm of the densest oscillations occurring at a current of 5 x 10 10 a/m 2 with black color. the magnetizing oscillation density in the graph shows that the application of large electric currents requires less time to change the direction of spin [8]. based on the overall analysis, we can see that the injected electric current density variation is very influential on the domain wall, the domain structure, and the magnetization graph against time (m-t). following the theory that current injection will affect the magnetic domain, the magnetization value can produce a pressure domain wall in the direction of electron flow. the domain wall pressure will result in a change in magnetization as the current density increases [9]. the effect of nanowire diameter variation on the total energy of permalloy nife materials on the stt (spin transfer torque) phenomenon this observation was carried to determine the effect of variations in the nanowire's diameter on nife permalloy material's total system energy. the energy contributing to this system includes total energy, demagnetization energy, and exchange energy in every electric current density. analysis of the effect of nanowire diameter on energy through a graph of the energy relationship to electric current density plotted using origin software when t = 6 ns, as shown in figure 7. (a) (b) figure 7. the graph of the relationship energy to electric current density on diameter 10 and 20 mm for polarization material (a) 1 and (b) 0,5 terms of energy per unit volume represented system energy at different diameters in each variation of electric current density and material polarization. the first analysis that will be carried out on system energy is the analysis of total energy. the total energy produced will increase along with the increase in the injection electric current density. the total energy will 8 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 also increase as the diameter of the nanowire varied gains. the exchange energy will increase along with the increase in the injection electric current density, but the energy will decrease along with the rise in the nanowire diameter. along with the increase in the density of the injected electric current, the resulting demagnetization energy will decrease and increase when the nanowire diameter is varied. the effect of material polarization variations on the movement speed of domain walls in nanowire-shaped nife permalloys resulting in the stt (spin transfer torque) phenomenon observation of the speed of movement of the domain wall in the nife permalloy material in the form of a nanowire due to the influence of variations in material polarization on the spin phenomenon of transfer torque is done using a time-resolved imaging method, which is to calculate the change in the position and time-domain wall represented in the corresponding image [10]. these results are described in the table form the mean velocity of the domain walls' movement, as in table 2. tabel 2. the average velocity of the movement of the domain walls when injected with an electric current density at a diameter of 10 nm and 20 nm no. j (a/m 2 ) average velocity (m/s) d = 10 nm average velocity (m/s) d = 20 nm p = 0,5 p = 1 p = 0,5 p = 1 1. 5 x 10 10 0 5,56 0 5,09 2. 10 x 10 10 3,71 6,67 3,09 5,82 3. 15 x 10 10 4,55 7,64 4,00 6,91 4. 20 x 10 10 5,64 9,46 5,27 8,17 based on the average velocity data in the table, it can be seen that when the polarization of a given material is the same, at different nanowire diameters, the average velocity of the movement of the domain walls along with the increasing of the injected electric current density is greater. however, the average velocity of the movement of the domain walls when given the same polarization, as the nanowire diameter increases, the average velocity of the domain walls' movement will decrease. when a given nanowire diameter is the same, at different polarization of materials, the average velocity of the domain walls' movement, along with the increasing of the given electric current density, is greater. however, the average velocity of the domain walls movement when treated giving polarization of different material at the same diameter, the greater the polarization is the greater speed of the domain walls movement. the increasing speed of the movement of the domain walls shows, the faster the resulting magnetization process. in this case, the material's polarization is directly proportional to the magnetization of the material [11]. the polarization factor of this material contributes significantly to the magnitude of the velocity of the domain walls' movement. conclusions based on the discussion of the results of research regarding the study of phenomenon stt on permalloy nife material, it can be seen that the injected electric current density can affect the magnetization value of the material. the effect given can be seen based on the domain wall's 9 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 1 – 9 submitted : january 11, 2019 accepted : march 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20555 position, the structure of the domain wall, and the magnetization graph against time (m-t). the total energy in a ferromagnetic system can be affected by the size of the nanowire diameter. the effect given is that the larger the nanowire diameter is in the polarization of the same material, the total energy will increase, the exchange energy decreases, and the demagnetization energy increases with increasing electric current density variations. the domain wall's speed is influenced by the increasing variety of electric current density, but the polarization of a given material also affects the speed. the greater the polarization applied to the same diameter, the greater the movement of the domain walls. references [1] s a wolf, d d awschalom and r a buhrman, 2001, spintronics: a spin-based electronics vision for the future, journal of physic, volume 294 (5546), page 1488-1495. [2] ismail, 2013, studi mikromagnetik proses magnetisasi dan spektrum suseptibilitas ferromagnetik elemen diamond-spaped, tesis, depok: universitas indonesia. [3] t l gerretsen, 2008, spin transfer torque in ferromagnetic materials, journal of physic, volume 8(1), page 18. [4] r a putu, 2010, bahan isolasi keramik, skripsi, denpasar: fakultas tekhnik universitas udayana. [5] r d michael and m j donahue, 1997, head to head domain walls in soft nano-strips: a refined phase diagram, journal of physic, volume 3(1), page 1-3. [6] y nakatani, a thiaville, j miltat and n vernier, 2004, domain wall motion by spin-polarized current: a micromagnetic study. journal of physics, volume 95(1), page 1-5. [7] v vlaminck and m bailleul, 2008, current-induced spin wave doppler shift, journal of physics, volume 322(1), page 410413. [8] m franchin, 2009, multiphysics simulation of magnetic nanostructures, thesis, malaysia: university of southampton. [9] t m atmono and yunanto, 2002, efek giant magnetoresistance pada logam peralihan co, ni, cu, jurnal sains, volume 6(1), page 58. [10] mardona, 2012, dinamika domain wall dan efek anisotropi pada material ferromagnet co dan ni berbentuk nanowire, tesis, jakarta: universitas jakarta. [11] g bertoti, 1998, hysteresis in magnetism, new york: academic press. 58 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 the flow rate characteristics of co gas emissions using simflow 3.1 eka febriyani 1,a and nuroh hidayati 1 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no 37 kampus tegalboto jember a ekafebri6861@gmail.com abstract. carbon monoxide (co) is a type of pollutant produced by industrial activities and is emitted through gas exhaust flues. simulation activities are considered to provide a lot of information regarding the distribution of co gas flow in the air. this paper will analyze the velocity and pressure distribution characteristics of co gas to predict the accumulation of co gas at various variations in the distribution distance of the gas. simulation activities are carried out using simflow 3.1, a software capable of simulating fluid dynamics by emphasizing the ease of application. the simulation results show that the flow rate of co gas is proportional to the amount of gas pressure generated at each distribution distance of the gas. the co gas flow shows a fairly stable movement when identified at a distance of more than 30 m. this indicates that a mass of co gas will be transmitted in the same amount over a distance of up to 70 m. the largest gas accumulation was obtained at a distance of 20 m from the source, which was indicated by the smallest gas flow velocity of 3.87 x 10 -3 m/s. keywords: simflow 3.1, chimney, co. introduction carbon monoxide (co) is the most abundant pollutant element compared to other pollutants in the atmosphere. statistical data shows that the amount of co gas has a percentage of 80% 90% in the earth's surface area [1]. environmental conditions much influence the distribution of co in an area. microorganisms can eliminate this distribution in the soil. open land, which is rare nowadays, causes the amount of co gas to increase. carbon monoxide is a primary pollutant source. these pollutants play a role in global climate change, especially global warming. carbon monoxide is a dangerous pollutant, which at high gas levels can cause death in humans. carbon monoxide (co), which is sucked into the lungs, will participate in blood circulation and will block the entry of oxygen that the body needs [2]. this can occur because co gas is a metabolic poison, so it reacts metabolically with blood. very high concentrations of co gas can cause death [3]. as a result of carbon monoxide for health is not irritating but very dangerous/poisonous, it is called the "silent killer". co gas is hazardous if inhaled by humans. it will replace the position of oxygen related to hemoglobin in the blood. co gas reaction with hemoglobin is 200 times more dangerous than the reaction of oxygen with hemoglobin [4]. the flow characteristics of co gas as fluid are essential to study to determine the extent of co gas distribution in an area. we can make preventive efforts to analyze areas that are relatively safe from accumulated pollutant gases. the pattern of the distribution of pollutant gases is vital to explore so that the gas exhaust can release pollutant gas as high as possible. this is necessary so that pollutants do not easily contaminate the chimney area, which is close to the ground. through a simulation activity, fluid flow characteristics can be developed without relatively high experimental costs. in this research, the fluid flow characteristics simulation will be performed under distance variations using the computational fluid dynamic (cfd) method. this cfd studies the prediction of fluid flow and heat transfer by solving mathematical equations. cfd 59 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 has been widely used in various problems related to fluid flow, one of which is dispersion [5]. previous researchers have carried out the flow characteristics of the fluid (gas), which were analyzed in a certain gas channel. using the ansys cfd fluent software, fathoni (2018) analyzed circular pipes' fluid characteristics with turbulent flow types [6]. mahan (2009) investigated the spread of so2 gas from stack emissions using computational fluid dynamics (cfd) [7]. based on research from mahan, we will research the flow rate of co gas and its characteristics. fluid is a substance that cannot withstand the forces and shear stress applied to it in an equilibrium state. fluid is elementary to follow the shape of space because the fluid resistance to deformation is minimal. in general, fluid can be divided into two, namely static and dynamic [8]. the fluid has several basic properties that can be used to differentiate between one type of fluid state and another. the different parameters include specific gravity, density, pressure, viscosity, and temperature [9]. research on fluid flow in home industrial chimneys uses the cfd method using simflow 3.1 software. this research was conducted by varying the size of the pollutant distribution distance of co gas in the chimney at a certain point. the results of this study are expected to provide additional lessons about the distribution of pollutants because in indonesia, the model for simulating the spread of contaminants has not been widely used, while the need for the food or electricity industry is increasing, so there is a need for more studies on this research. in general, the fluid flow equation used in this simulation process is the navier-stokes equation, which includes the continuity equation and the momentum equation [10]. a. continuity equation ( ) ( ) ( ) (1) b. momentum equations momentum towards the x-axis: ( ) ( ) ( ) ( ) ( ) (2) c. momentum equations momentum towards the y-axis: ( ) ( ) ( ) ( ) ( ) (3) research methods this research was conducted to determine the characteristics of the velocity and pressure of co gas in several distribution distances using the computational fluid dynamic (cfd) method. the solutions of differential equations describing fluid flow are solved using simflow 3.1. the simulation process is divided into two stages, namely pre-processing and processing. the preprocessing stage includes making geometry and meshing models, identifying the mesh's boundaries, and checking the mesh. the processing stage includes determining boundary conditions, determining computational methods and parameters, and running simulations. the input parameters used in the simulation process are given in table 1. 60 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 table 1. parameter input no parameter unit quantity 1 distance of x m (10-70) 2 distance of y m 16 3 distance of z m 24 4 viscosity of co m 2 /s 1.42 x 10 -5 the geometry of the simulated gas source and distribution area is shown in figure 2.1. the addition of blocks in the area around the head of the gas emission is intended to see in more detail the site to be analyzed. in this case, the length of the spread (x-axis) is varied, while the blocks' size in the y and z directions is fixed. the design of the pollutant distribution area is given in figure 1. figure 1 design of pollutant distribution area arrangements for the meshing process are made on the mesh beam by setting the size to the minimum and maximum values as the cells size in the initial mesh. we measure the division value in the direction (x, y, z) = (45, 20, 20). the next step is to determine the solver used in this simulation, namely pimple foam with a compressible flow and a transient time type. this selection is based on mahan's research in 2009. the next step is to determine the boundary conditions to determine the conditions' character for each boundary. the chimney_inlet boundary condition is set to be mass flow inlet with a constant flow rate of 10 m 3 /s and a pressure gradient of zero. the mass flow inlet is the area where the co emission is released (the upper face of the stack). the second boundary condition, scalar type on chimney_inlet, is changed to 1. this means that it can operate in the range 0-1. value 1 indicates that the variable can operate 100%. 61 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 the inlet limit is set at the limit condition atmospheric inlet to define the flow current. the determination of the atmospheric inlet conditions also greatly affects the characteristics of the gas flow in the flue. these conditions establish a suitable inlet velocity profile for the atmospheric boundary layer. this profile is derived from the friction velocity, flow direction and vertical direction where, the flow direction is the direction that determines the value vector of the x-axis coordinate system. the vertical direction is a vector that defines the vertical axis parallel to the force of gravity. the next step is setting the initial conditions by activating the initialize potential flow. initialization is an initial estimate of the boundary conditions where we will start the calculation. this activation is performed to calculate the initial velocity and pressure by solving the potential flow problem before the actual simulation. this possible flow solution is much easier to obtain and can provide an excellent initial value of the velocity field. before the time simulation process, the time step value is set to 0.001 with the last time limit of 200 s. this simulation uses time interval one by selecting the adjustable run time type to save data for each simulation time break. results and discussion the results obtained from this study are the value of flow rate (velocity) and co gas pressure from several variations in the distribution distance as a function of time. observations were made at 10 m intervals, starting from a distribution distance of 10 m to 70 m. the value of flow rate and pressure can be seen in table 3.1. the flow velocity of co gas was analyzed in three different flow directions, including the x (ux), y (uy), and z (uz) directions. analysis of velocity on variations in the distribution distance by observing the velocity profile for each direction (ux, uy, and uz) as a function of the distance x, it can be said that the velocity of co gas in the x-direction has the smallest value. this shows that the co particles are slow to move in the horizontal x-direction. the change in gas concentration is assumed to be small enough that co gas can last long enough in the xdirection. besides, it is interesting to note that at a distance of 20 m, co gas always experiences a significant decrease in velocity throughout the observation time. in this case, the gas pressure factor is considered the main cause of the gas's characteristics. 62 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 figure 2. flow rate of co gas in the x direction (ux) figure 3. flow rate of co gas in the y direction (uy) 2 4 6 8 10 12 14 0 20 40 60 80 f lo w r a te ( v e lo c it y ) ( x 1 0 -3 ) m /s distance (m) t=20 t=40 t=60 t=80 63 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 figure 4. flow rate of co gas in the y direction (uy) in general, the velocity values on the x, y, and z axes have the same pattern. to find out the resultant velocity, a detailed calculation of the resultant velocity of co gas is shown in table 2. the co gas flow rate profile at variations in gas movement mileage is presented in figure 5. it can be seen that the pattern of the flow rate represented at 20 s, 40 s, 60 s, and 80 s has the same pattern even though the values are different. table 2. resultant velocity at a distance of 10 m to 70 m resultant of velocity x 10 -3 (m/s) t (s) 10 m 20 m 30 m 40 m 50 m 60 m 70 m 0.39 8.46 6.33 27.28 27.27 14.16 27.28 27.28 10 14.25 8.69 14.15 14.25 27.28 14.25 14.16 20 8.54 5.88 8.54 8.54 8.52 8.54 8.52 30 8.53 5.23 8.53 8.53 8.52 8.53 8.52 40 7.90 4.17 7.93 7.92 7.93 8.53 7.93 50 8.67 4.04 8.65 8.65 8.65 8.66 8.65 60 9.99 3.87 10.24 10.19 10.19 10.19 10.19 70 12.51 7.91 12.51 12.51 12.53 12.51 12.53 80 13.47 9.59 13.47 13.41 13.47 13.47 13.47 90 14.76 10.03 14.76 14.76 14.79 14.76 15.54 100 16.45 10.55 16.45 16.63 16.45 16.50 15.50 110 16.95 11.26 17.52 17.38 22.46 17.38 17.52 120 17.48 11.65 17.46 17.48 17.52 17.48 17.54 130 17.71 10.63 17.69 17.73 17.73 17.71 17.69 140 17.25 10.63 17.25 17.25 17.25 17.25 17.17 150 15.68 10.59 15.68 15.60 15.68 15.68 15.68 160 17.52 10.93 17.47 17.57 17.47 18.50 17.47 64 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 resultant of velocity x 10 -3 (m/s) t (s) 10 m 20 m 30 m 40 m 50 m 60 m 70 m 170 18.71 8.99 18.64 18.71 18.71 18.70 18.71 180 19.86 9.55 19.93 19.93 8.82 19.86 19.92 190 20.13 8.78 20.13 20.21 20.13 20.21 20.14 200 20.48 9.98 20.48 20.48 20.48 20.48 20.48 figure 5. profile of resultant velocity at distance variation pressure analysis over distance variations the value of co gas pressure is observed at several different positions in the x-axis direction, namely at a distance of 10 m to 70 m. the simulation results show that the pressure data fluctuates over 200 seconds, which is depicted on the pressure vs. distance graph, for a specific time (figure 3.5). the highest amplitude is obtained at a distance of 20 m. this corresponds to the amount of co emitted. the longer the observation time and the farther the distance, the pressure decreases until it becomes a relatively stable state. the value of gas pressure indicates this at a relatively constant observation distance variation. co gas pressure value data from several variations in the distribution distance is given in table 3. table 3. pressure values at a distribution distance of 20 m to 70 m t (s) gas pressure of co (10 -2 pa) 10 m 20 m 30 m 40 m 50 m 60 m 70 m 0.39 5.90 2.01 4.80 4.80 4.80 4.80 4.80 10 2.00 1.00 2.01 2.00 2.00 2.00 2.01 20 1.71 1.59 1.71 1.70 1.71 1.71 1.71 30 1.86 1.84 1.86 1.85 1.86 1.85 1.86 65 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 t (s) gas pressure of co (10 -2 pa) 10 m 20 m 30 m 40 m 50 m 60 m 70 m 40 2.10 1.62 2.10 2.10 2.10 2.10 2.10 50 2.27 2.25 2.27 2.26 2.27 2.26 2.27 60 2.72 2.44 2.71 2.72 2.72 2.72 2.72 70 2.82 2.36 2.82 2.82 2.83 2.82 2.83 80 2.91 2.82 2.91 2.87 2.87 2.87 2.87 90 3.36 3.36 3.36 3.36 3.38 3.36 3.38 100 3.24 3.19 3.38 3.25 3.23 3.26 3.66 110 3.35 3.39 3.39 3.37 3.37 3.37 3.39 120 3.37 2.36 3.38 3.37 3.37 3.37 3.37 130 2.98 2.97 3.40 3.00 3.00 2.97 2.93 140 2.98 3.00 3.00 2.99 2.98 3.00 3.00 150 3.12 3.08 2.95 3.08 3.10 3.11 3.10 160 3.31 3.28 3.24 3.27 3.24 3.49 3.24 170 3.60 3.57 3.58 3.59 3.60 3.57 3.60 180 3.73 3.71 3.73 3.71 3.71 3.70 3.71 190 3.33 3.32 3.33 3.32 3.33 3.37 3.32 200 3.44 3.34 3.44 3.43 3.44 3.44 3.44 figure 6. pressure variation profile as a function of distance based on figure 6., we can see that the pressure distribution of co gas has almost the same characteristics as the gas velocity distribution. therefore, changes in the velocity values that occur in the co gas flow can be affected by the gas pressure state. the simulation results show that the higher the gas pressure, the greater the gas flow velocity produced. the resulting gas pressure at a distance of 30 to 70 m does not show much change. one of the causes of this situation is that the simulated co gas characteristics are limited to incompressible gas conditions. the pressure state at 40 seconds, for the position of the gas as far as 20 m, does not show a significant change. the data obtained in this case is 0.5 x 10-2 pa. in figure 6 we can see that the pressure-distance relationship curve has the same shape as the velocity 66 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 distance curve. thus, the two parameters can be said to be correlated. ni'am states that the gas pressure is directly proportional to the velocity of the gas produced [11]. the graph of the pressure to velocity relationship is shown in figure 7. figure 7. relationship between pressure and resultant velocity at 80 s observation time. conclusions the co gas flow rate as a function of the distribution distance has the same distribution pattern for the entire observation time. the flowing movement is relatively stable after a distance of 30 m. the minimum pressure of co gas is generated at a distance of 20 m, while at a distance of 30 m to 70 m, it does not show a large enough change. the amount of co gas pressure is directly proportional to the magnitude of the velocity of the gas produced. acknowledgements the author thanks to lp2m universitas jember for providing research funding assistance through hibah keris 2018. references [1] s. serkey, f. jassen, s. wallah, 2011, tingkat pencemaran udara co akibat lalu lintas dengan model prediksi polusi udara skala mikro, jurnal ilmiah media engineering, volume 1(2), page 119-120. [2] akmal, 2009, dampak gas co terhadap kesehatan, http://vhatal(akmal): dampak gas co terhadap kesehatan.htm, accessed on januari 25, 2019. [3] s. benny, 2005, telaah studi amdal pada tahap operasional pabrik peleburan timah (smelter) pt. laba-laba multindo pangkal pinang-bangka belitung, skripsi, semarang, fakultas teknik unissula. 67 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 2, page 58-67 eissn : 2747-173x submitted : august 9, 2020 accepted : october 10, 2020 online : november 24, 2020 doi : 10.19184/cerimre.v3i2.23546 [4] m. weaver, lindell k, 2009, carbon monoxide poisoning, the new england journal of medicine, 360, page 1217-25. [5] t. w. hubber, a. bell, b. schwarz w, 2006, application of cfd simulations for shortrange atmospheric dispersion over open fields and within arrays of buildings, proceeding of the symposium at the 14th on the applications of air pollution meteorology, atlanta, 30 januari – 2 februari. [6] f. fathoni, 2016, studi numerik sudden expansion meso combustor pada micro power generator, skripsi, jember, teknik mesin fakultas teknik universitas jember. [7] m. victor, 2009, simulasi penyebaran so2 dari emisi cerobong menggunakan computational fluid dynamic (cfd), skripsi, bogor, institut pertanian bogor. [8] f. fadhili, 2016, studi numerik studi numerik sudden expansion meso combustor pada micro power generator, skripsi, jember, teknik mesin fakultas teknik universitas jember. [9] a. a. gazali, 2018, analisa aliran fluida menggunakan cfd dengan variabel viscosity pada preproses injeksi molding, skripsi, jember, teknik mesin fakultas teknik universitas jember. [10] h. k. versteeg, w. malalasekera, 1995, an introduction to computational fluid dynamics the finite volume method, new york, john wiley & sons. [11] a. g. ni’am, 2009, simulasi dispersi gas polutan s02, h2s, dan co dengan menggunakan program computational fluid dynamic (cfd), skripsi, bogor, institut pertanian bogor. 30 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 optimization of the main landing gear structure of lsu-02ngld fajar ari wandono 1,a 1 aeronautics technology center, lapan, jalan raya lapan-rumpin desa sukamulya, rumpin, bogor 16350, indonesia a email fajar.ari@lapan.go.id abstract. the mass of the landing gear structure becomes an important aspect of the total mass of the uav (unmanned aerial vehicle). therefore, many efforts have been made to reduce the mass of the landing gear by performing structural optimization. reducing the mass of the landing gear structure can be used as a substitute to increase the payload on the uav. the landing gear structure in this paper is the main landing gear of lsu-02ngld (lapan surveillance uav series 02 new generation low drag). lsu-02ngld is a uav that has 2.9 m of wingspan with a total mass of 21 kg. this paper aims to optimize the main landing gear structure so that optimization can reduce the mass. the optimization was carried out using the finite element software by modeling the main landing gear structure as a 1d beam element. there were 9 beam elements in the main landing gear structure model. the cross-sectional width (w) and the cross-sectional height (h) for each element were used as design variables. the objective of the optimization was to minimize the mass while maintaining maximum bending stress not greater than 20 mpa, displacement in y-direction not greater than 1 mm, and displacement in z-direction not greater than 0.1 mm. the optimization result showed that the mass reduction of the main landing gear structure was 50%, with all constraints fulfilled. keywords: main landing gear structure, unmanned aerial vehicle, lsu-02ngld, optimization, finite element, beam element. introduction the landing gear structure has a role in supporting the maneuvers of a uav while on the ground, such as taxiing, take-off, and landing. the mass of the landing gear structure is important to the total mass of the uav. therefore, many efforts have been made to reduce the mass of the landing gear structure by optimizing the structure. reducing the mass of the landing gear structure can be used as a substitute to increase the payload on the uav [1]. the landing gear structure in this paper is the main landing gear structure of lsu-02ngld (lapan surveillance uav series 02 new generation low drag). lsu-02ngld has a wingspan of 2.9 m with a total mass for the takeoff is about 21 kg [2]. lsu-02ngld is shown in figure 1. 31 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 figure 1. lsu-02ngld [2] matta et al. performed design optimization on a main landing gear structure and axle of the uav using a 2d element model. the landing gear and axle structure were divided into 11 areas whose thickness varied to obtain optimum mass. the result of this optimization was the mass could be reduced from 6 kg to 4.15 kg [1]. teja & govindarajulu [3] optimized the design of a main landing gear structure by reducing the area of the main landing gear structure while still maintaining the design's safety. the optimization results were then analyzed using static analysis to determine the displacement, force, and stress in the structure. theoretical background in this paper, the main landing gear will be modeled on several beam elements. a beam is a structure that has a small cross-sectional dimension relative to its length. a beam is an important load-carrying component that internally experiences compressive, tensile, and shear stresses due to the loads given to the structure [4]. for modern structures, the mass reduction becomes very important besides performance. therefore, the beam structure design must be well calculated to reduce the mass of the structure. figure 2. the stiffness matrix of the simple beam [5] where k is the stiffness of the element, e is the modulus of elasticity, a is the cross-sectional area, l is the length of the element, i is the moment of inertia, u is the axial displacement, v is 32 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 the lateral displacement, θ is the rotation. the bending stress can be calculated by equation 1 below. σ=-my/i (1) where σ is the bending stress, m is the bending moment, y is the distance to the neutral axis, i is the moment of inertia. several important things to consider in optimization are design variables, objectives, and constraints. design variables can change related to dimensions, grid location, and material properties either directly or indirectly [6]. the objective function is to minimize or maximize the considered responses. the objective functions of optimization are usually mass, strain energy, frequency, and compliance [6]. a constraint is one or more considered responses that are expected to be constrained in an optimization process. constraints are usually in the form of stress, displacement, and mass fraction. according to larsson [7], design variables representing the thickness of the structure and or cross-sectional area that can minimize physical quantity such as mass, strain energy, or deflection by satisfying the constraints can be referred to as size optimization. here is a general formula for structure optimization. { ( ) { ( ) ( )= (2) where f(x) is optimization's objective, g(x) and h(x) is optimization's constraint. according to [8], the purpose of optimization is to get the best design against several priority criteria or constraints. therefore, a design that includes an optimization process always considers certain objectives such as strength, deflection, mass, and others according to their needs. materials and methods the material used in this paper was assumed as aluminum alloy 7075-t6 material. this material was also used by teja et al [3] and yildirim et al [9] in their paper. table 1. mechanical properties of al 7075-t6 [3,9] al alloy modulus of elasticity (gpa) yield strength (mpa) poisson's ratio density (kg/m3) 7075-t6 72 505 0.33 2850 the loads on the lsu-02ngld used casr part 23 in appendix c concerning basic landing conditions as a reference. this reference was also used by nguyen [10] and wandono et al [11]. here are the loads on the main landing gear structure when landing. 33 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 table 2. the loads on the main landing gear structure [11] load value (n) vertical load (vr) each main landing gear structure 245 horizontal load (dr) each main landing gear structure 78.75 the following figure is a flow chart for performing optimization of the main landing gear of lsu02ngld. start initial design of main landing gear structure fe modeling (1d beam) model verification initial static analysis (stress and displacement) determine design variable, objective, and constraints fulfill the target? optimization using finite element rendering optimized model finish yes no figure 3. flow chart this paper started with the initial design of the main landing gear structure. in this initial design, the main landing gear structure had a uniform cross-section from the base to the tip, as shown in figure 4. figure 4. the initial design of the main landing gear structure (mm) the initial design of the main landing gear was then modeled into a finite element using a 1d beam element. here is a finite element model of the main landing gear. 34 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 figure 5. finite element model of the main landing gear structure figure 5 shows that there are 9 elements (black) and 10 nodes (red) in the finite element model of the main landing gear structure. the cross-section used in the finite element model of the main landing gear is rectangular with a length of 78 mm and a height of 21 mm, as shown in figure 4. the finite element model of the main landing gear was then verified to determine the finite element model is similar to the initial design of the main landing gear. verification will show a 3d image of the finite element model after defining its cross-sectional. figure 6. model verification model verification in figure 6 shows that the finite element model of the main landing gear is similar to the initial design, as shown in figure 4. node element 35 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 figure 7. load and boundary condition figure 7 shows the load and boundary conditions used in the finite element model of the main landing gear structure. the loads are subjected at the end of the main landing gear structure (node 10) with a value of 245 n in the y-direction and 78.75 n in the z-direction, as shown in table 2. the boundary condition is fixed at node 2. the location of the boundary conditions follows the bolts' location for joining the main landing gear structure to the fuselage of lsu02ngld. here are the results of the initial design static analysis of the main landing gear structure using the finite element software. the results are bending stress, displacement in the y-direction, and displacement in the z-direction. figure 8. bending stress distribution 36 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 figure 8 shows the distribution of bending stress on the main landing gear structure. the maximum bending stress occurs in element 2, adjacent to the boundary condition, with a value of 10.9 mpa. figure 9. displacement in y-direction figure 9 shows the displacement in the y-direction of the main landing gear structure model. the maximum displacement occurs at the end of the structure at node 10 with a value of 0.325 mm. figure 10. displacement in z-direction figure 10 shows the displacement in the z-direction of the main landing gear structure model. the maximum displacement occurs at the end of the structure at node 10 with a value of 0.0645 mm. for the maximum displacement, both y-direction and z-direction are at the loading location. 37 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 the bending stress, displacement in the y-direction, and displacement in the z-direction will be used as references to determine the constraints for optimizing the main landing gear structure. the main landing gear structure model consisted of 9 beam elements. the design variables used were cross-sectional height (h) and cross-sectional width (w) for each element. here is a table of design variables for the main landing gear structure optimization. table 3. design variables no design variable lower bound upper bound interval 1 h1 10 21 10≤h1≤21 2 h2 10 21 10≤h2≤21 3 h3 10 21 10≤h3≤21 4 h4 10 21 10≤h4≤21 5 h5 10 21 10≤h5≤21 6 h6 10 21 10≤h6≤21 7 h7 10 21 10≤h7≤21 8 h8 10 21 10≤h8≤21 9 h9 10 21 10≤h9≤21 10 w1 50 78 50≤w1≤78 11 w2 50 78 50≤w2≤78 12 w3 50 78 50≤w3≤78 13 w4 50 78 50≤w4≤78 14 w5 50 78 50≤w5≤78 15 w6 50 78 50≤w6≤78 16 w7 50 78 50≤w7≤78 17 w8 50 78 50≤w8≤78 18 w9 50 78 50≤w9≤78 for the main landing gear structure optimization, the objective was to minimize the mass. the constraints were bending stress, displacement in the y-direction, and displacement in the zdirection. based on the static simulation for the initial design with a uniform cross-section, the maximum bending stress is 10.9 mpa, the maximum displacement in the y-direction is 0.325 mm, and the maximum displacement in the z-direction is 0.0645 mm. when mass optimization is carried out on a structure, the mass value will be inversely proportional to the stress and displacement. this is because a smaller mass than the initial mass will make the stress and displacement increase. therefore, the upper limit of the stress and displacement optimization results must be considered to keep the structure safe. from table 3, it can be seen that there are 18 design variables for the main landing gear structure optimization with an upper limit of 21 mm and a lower limit of 10 mm for crosssectional height and an upper limit of 78 mm, and a lower limit of 50 mm for cross-sectional width. for the main landing gear structure optimization, the constraints and their limits are presented in table 4. table 4. constraints and their limits constraints value bending stress (σ) 10 mpa ≤ σ ≤ 20 mpa displacement in the y-direction (uy) uy ≤ 1 mm displacement in the z-direction (uz) uz ≤ 0.1 mm 38 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 the bending stress, displacement in the y-direction, and displacement in the z-direction, used as constraints, must be within these limits in the optimization results. if optimization results obtain the constraint value out of bounds, something is wrong in the optimization process and it has to be redefined again. results and discussion here is the optimization cycle of the main landing gear structure. fig. 11 shows the design variables cycle; they are cross-sectional height (h) and cross-sectional width (w). figure 11. design variable cycle graph the bottom line set is the cross-sectional height (h) cycle, and the top is the cross-sectional width (w) cycle. the results of the design variable cycle stopped in the 15th iteration because the results had met the specified constraints. there was a design variable whose optimization value was similar to their initial value, and it occurred in element 2, where the element was close to the boundary condition. the biggest changes occurred at the end (element 7, 8, 9) and at the base (element 1) of the main landing gear structure, where the bending stress that occurred tends to be small. the objective cycle result is presented in figure 12. 39 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 figure 12. objective cycle graph from figure 12 above, it can be seen that the initial mass of the main landing gear structure is about 2.05 kg, and in the 15th iteration, the optimized mass is 1.025 kg. thus, the optimized main landing gear structure results in a mass reduction of about 50%. table 5. design variable comparison between initial and optimized design no design variable initial optimized 1 h1 21 10 2 h2 21 21 3 h3 21 21 4 h4 21 14.15 5 h5 21 12.96 6 h6 21 11.91 7 h7 21 10 8 h8 21 10 9 h9 21 10 10 w1 78 50 11 w2 78 78 12 w3 78 71.13 13 w4 78 75.17 14 w5 78 68.06 15 w6 78 58 16 w7 78 50 17 w8 78 50 18 w9 78 50 the optimization results on the design variable were then displayed on the finite element model of the main landing gear structure. 40 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 figure 13. optimized the main landing gear structure from figure 13, it can be seen that the results of the optimization of the main landing gear structure with bending stress and displacement in the y-direction and z-directions constraints get the results of a taper shape structure. taper means the difference in height and width of the cross-section from the base to the tip of the main landing gear structure. for elements 1 and 9, because they have small bending stress, the height and the cross-sectional width of the optimization results are also the smallest. here are the results of bending stress, displacement in the y-direction, and displacement in the z-direction of the optimized design. figure 14. bending stress distribution of the optimized design figure 14 is used to determine whether the results of the optimization of the structure fulfill the constraints. the figure above shows that the maximum bending stress on the optimized main landing gear structure is 19.9 mpa at element 5. this fulfills one of the constraints that the 41 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 maximum bending stress is 20 mpa. however, the maximum bending stress position in the optimization is different from the initial results. this is because the cross-sectional section of element 5 has been changed to be smaller, which makes the moment of inertia smaller and makes the bending stress larger. figure 15. displacement in the y-direction of the optimized design figure 15 above is also used to determine whether the results of the optimization of the structure fulfill the constraints. the figure above shows that the maximum displacement in ydirection on the optimized main landing gear structure is 1 mm at node 10. this also fulfills one of the constraints that the maximum displacement in the y-direction is 1 mm. figure 16. displacement in the z-direction of the optimized design 42 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 from figure 16, it is known that the maximum displacement in the z-direction on the optimized main landing gear structure is 0.1 mm at node 10. therefore, this also fulfills one of the constraints of the maximum displacement z-direction is 0.1 mm. table 6. comparison between initial and optimized design configuration σ max (mpa) uy max (mm) uz max (mm) mass (kg) initial 10.9 0.325 0.0645 2.05 optimized 19.7 1 0.1 1.025 the next step was to redraw the optimization results because all requirements such as design variables and constraint constraints had been fulfilled. here is the result of the optimized main landing gear structure. figure 17. the optimized main landing gear structure conclusions the optimization process has been carried out on the main landing gear structure of the lsu02ngld. the optimization process was carried out on the finite element software by modeling the main landing gear structure as a 1d beam element. there were 9 beam elements in the main landing gear structure. the design variables used were cross-sectional height (h) and cross-sectional width (w) for each element. the objective of this optimization was to minimize the mass with a maximum bending stress constraint not greater than 20 mpa, displacement in y-direction not greater than 1 mm, and displacement in z-direction not greater than 0.1 mm. the optimization result showed that the mass reduction of the main landing gear structure is 50%, with all constraints fulfilled. acknowledgements the author would like to express many thanks to mr. drs. gunawan s. prabowo, mt as head of the aeronautics technology center and to mr. ir. agus aribowo, m.eng for the support. 43 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 30 – 43 eissn : 2747-173x submitted : march 28, 2021 accepted : may 2, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24965 references [1] a.k. matta, g.v. kumar, and r.v. kumar, 2012, design optimisation of landing gear's leg for an un-manned aerial vehicle, international journal of engineering research and applications, volume 2, page 2069 – 2075. [2] f.a. wandono and m. adhitya, 2020, finite element analysis for composite wing structure of the maritime surveillance unmanned aerial vehicle, padang. [3] c. a. teja and c. govindarajulu, 2019, optimization of conventional type landing gear's leg, journal of engineering research and application, volume 9, no. 11, page 52 – 56. [4] s. darshan, a. varik, a. n. katti, a. k. singh and r. r. kamath, 2013, size and topological optimization of cantilever beam, journal of engineering trends and technology, volume 4, no. 5, page 2077 – 2082. [5] y. liu, 2003, lecture notes: introduction to the finite element method, cincinnati: university of cincinnati. [6] j. p. leiva, 2004, topometry optimization: a new capability to perform element by element sizing optimization of structures, 10th aiaa/issmo multidisciplinary analysis and optimization conference, new york. [7] r. larsson, 2016, methodology for topology and shape: optimization: application to a rear lower control arm (master's thesis), chalmers university of technology, goteborg. [8] a. d. kewate, r. r. ghadge and s. r. kewate, 2017, weight optimization of composite cantilever structure, journal of material science and mechanical engineering, volume 4, no. 4, page 172 – 178. [9] o. yildirim, e. gunay, o. anil and c. aygun, 2014, analysis of a skid type landing gear of a rotary wing uav by experimental and numerical methods, proceedings of the 4th international congress apmas, fethiye. [10] t. d. nguyen, 2010, finite element analysis of a nose gear during landing. unf theses and dissertations, university of north florida, florida. [11] f. a. wandono and m. adhitya, 2019, analisis kekuatan struktur komposit dengan ply drop off pada roda pendarat utama pesawat nir awak menggunakan metode elemen hingga, jurnal teknologi dirgantara, volume 17, page 29 – 40. 38 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 study of dielectric and adsorption properties of activated carbon prepared from water hyacinth using koh as an activating agent mochammad ghiffari 1,a , wenny maulina 1 , and agung tjahjo nugroho 1 2 departmen of physics, faculty of mathematics and natural sciences, universitas jember, jember 68121, east java, indonesia a arifary430@gmail.com abstract. activated carbon can be produced from the combustion of a materials containing carbon that has been activated using activator substances. in this paper, potassium hydroxide (koh) was selected as an activating agent. the influence of koh concentration was investigated to determine the dielectric and adsorption properties of activated carbon derived from water hyacinth. drying water hyacinth was carbonize in the furnace at a temperature of 400°c followed by chemical activation with variation concentration of koh solution that used are 25%, 30%, and 35% (w/v) respectively. the results show that the best activated carbon derived from water hyacinth was obtained using 35% (w/v) koh solution as an activating agent with the dielectric constant is 4.04 while iodine number of 514.6 mg/g. keywords: water hyacinth, activated carbon, koh, dielectric constant, iodine number introduction indonesia is a country that has high biodiversity, but all of them have not been fully utilized. one of the biodiversity that is easily found is water hyacinth. water hyacinth (eichhornia crassipes), the aquatic biomass, has attracted significant attention due to its extremely rapid growth, presenting serious challenges in navigation, irrigation and power generation [1-2]. water hyacinth has many benefits, one of which can be made into fertilizer for the growth of fluted pumpkin (telfairia occidentalis) [3], the diets of sheep [4], biodegradable board [5], biomass briquette [6], and activated carbon for phosphate removal from wastewater [7]. furthermore, water hyacinth is critical to be studied for its possibility as an alternative energy source [8]. for example, water hyacinth has been demonstrated to be useful to develop supercapasitors, for production ethanol and to improve the immune resistance of plants and animals [9]. carbon materials are a black residue containing impure carbon produced from the process of burning materials containing carbon elements. carbon materials can be produced from materials containing carbon by heating at high temperatures [10]. activated carbon is a carbonaceous solid derived from coal or biomass via thermal or thermochemical processes [2]. in general, activated carbon can be divided into physical and chemical activation. physical activation is a process of breaking carbon chains from organic compounds with the help of heat at temperatures of 800ºc to 900ºc [11]. meanwhile, chemical activation is soaking charcoal with chemical compounds before heating [12]. the chemicals that are usually used for activation are cacl2, mncl2, koh, ca(oh)2, zncl2, naoh, h3po4, h2so4, k2co3, na2co3 [13]. based on the fact that the activating agents potassium hydroxide (koh) performed much better than the other activating agent in terms of its ability to produce very high surface area carbon. koh was found to generate carbon with the highest porosity and surface area [14]. a number of studies mailto:aarifary430@gmail.com 39 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 have been carried out to using koh as an activating agent. hwa-young et al. synthesis of activated carbon from paper mill sludge by koh-activation [15]. yang et al. studied on the application of koh to produce activated carbon to realize the utilization of distiller’s grains [16]. pagketanang et al. investigated microporous activated carbon from koh-activation of rubber seed-shells for application in capacitor electrode [17]. jin-young and young-seak measure electrochemical properties of koh-activated lyocell-based carbon fibers for edlcs [18]. the number of pores and large surface area correlate with the adsorption power of activated carbon [12]. in this study, iodine number was carried out to determine the adsorption capacity of activated carbon prepared from water hyacinth at various concentrations of koh as an activating agent. aside from iodine number, measurement of electrical properties of activated carbon was also carried out. the use of activated carbon as a raw material for electronic devices, such as batteries, has been widely carried out. theoretical background the use of carbon materials have been used for many applications, such as batteries, supercapacitors, gas sensors and dye-sensitized solar cells [19]. over the years, the furnace has been used as a common heating method to manufacture carbon. in a furnace, heat is transferred through conduction and convection. the outer surface of the sample is in contact with the generated heat, which slowly diffuses inwards as a result of the thermal gradient between the surface and the core of the material’s particles [20]. activated carbon refers to a wide range of carbonized materials of high degree of porosity and high surface area. carbon structures contain the main functional groups such as carboxyl, carbonyl, phenol, lactone and quinone that are responsible for adsorbing contaminants. oxygen, hydrogen, sulphur and nitrogen are also present in the form of functional groups or chemical atoms in the activated carbon structure. the unique adsorption properties depend on the existing functional groups of activated carbon, which are derived mainly from activation processes, precursors and thermal purification [21]. potassium hydroxide (koh) has been widely used as an activating agent in activated carbon preparation. during the activation process, the following reaction take place [20,22]: (1) (2) (3) both mesopores and micropores are formed as a result of the intercalation of potassium into the carbon network during the activation. besides, there is also a possibility for a secondary reaction to occur as follows: (4) 40 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 the dielectric properties of the materials are very important in evaluating the penetration of energy that can be achieved [23]. the dielectric constant can be determined from the capacitance measurement, as follow [24]: (5) where “c” is capacitance (f), “ ” is the dielectric constant, “ ” is permittivity of the vacuum (8.85 10 -12 c 2 /nm 2 ), “a” is the area of the plates (m 2 ), and “d” is the plate separation (m). the product is called the permittivity of the medium and is denoted by , (6) for vacuum and . the dimensionless ratio: (7) is called the dielectric constant of the substance. as remarked before, the dielectric constant can be calculated as bellow (8) thus, the dielectric constant of a substance is the factor (>1) by which the capacitance increases from its vacuum value, when the dielectric is inserted fully between the plates of a capacitor. adsorption capacity of activated carbon mainly depends on its porosity and surface area. higher iodine numbers reflect better development of the microporous structure and higher adsorption abilities for low-molar-mass solutes [25]. the iodine sorption value (isv) was calculated according to the equation (6) bellow [26]: ( ) ( ) (9) where “isv” is iodine sorption value (mg/g), “a” is volume of iodine solution (ml), “b” is volume of sodium thiosulfate (na2s2o3) used (ml) “n(na2s2o3)” is concentration of sodium thiosulfate (n), “n(iodine)” is concentration of iodine (n), “ ” is mass of activated carbon (g) and “ ” is dilution factor. materials and methods preparation of water hyacinth activated carbon in this study, the stems of water hyacinth were used for the preparation of activated carbon. the stems of water hyacinth were cleaned, chopped into pieces and dried using oven for 24 h at 105°c until they become crispy. then the dried stems of water hyacinth was grinded until it 41 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 becomes powder. this powdered was heated up to 400°c in the furnace about 1 h to make relative charcoal. the water hyacinth charcoal was sieved to a mesh size of 200. to prepare activated carbon of water hyacinth, the charcoal was chemically activated using potassium hydroxide (koh) as activating agent with concentration of 25%, 30%, and 35% (b/v), respectively. the process continued by heating and stirring using magnetic stirrer hotplate at 80°c for 4 h. the sample was filtrate and washed with chemical of 2 m hcl followed by distilled water to make the sample neutral and put in the oven again for 2 h at 100°c. after this process, the activated carbon derived from water hyacinth ready to use in measurement. dielectric properties measurement dielectric properties were measured using lcr meter lutron 9183. the measurement of activated carbon derived from water hyacinth was carried out using a parallel plates capacitor. the activated carbon was poured in 31 mm × 31 mm × 4 mm rectangular planner moulds. the measurement procedure which is done by contacting the probe to a flat surface of sample, as shown in figure 1. the experiment was measured capacitance at a frequency of 10 khz. the dielectric constant was found by using equation (8). the measurement was repeated to all different concentration of potassium hydroxide (koh) activator. since the experimental variables are more in number it was planned to check the result and data through analysis of variance (anova). anova was used to estimate the statistical parameters. figure 1. set-up of dielectric properties measurement determination of the iodine sorption value (isv) a 5 g activated carbon derived from water hyacinth was mixture with a volume of 100 ml concentrated iodine solution (1 n). the mixture was allowed to stand for 15 minutes in order to reach sorption equilibrium between activated carbon and concentrated iodine solution. the aliquot amount of sample and iodine solution were titrated with 0.1 n sodium thiosulfate solution. the isv was calculated according to the equation (9). the measurement were conducted for each type of activated carbon. results and discussion dielectric properties dielectric materials are characterized by their dielectric properties. dielectric properties determine the ability of the material to absorb energy. the dielectric constant defines a measure of how much energy from an external electric field can be stored within a material through polarization mechanism [27-28]. the results in activated carbon electromagnetic constant are 42 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 shown as figure 2. from figure 2 can be seen the dielectric constant of the activated carbon increased with increasing concentration of activating agent. the dielectric constant of the activated carbon derived from water hyacinth using concentration of koh (25 wt%, 30 wt% and 35 wt%) are 2.78 ± 0.18, 2.82 ± 0.21, and 4.04 ± 0.29, respectively. the increase in the concentration of koh causes the dielectric constant value will also increase. an increase the magnitude of dielectric constant is thought to be due to an increase in the surface area of activated carbon. the use of koh as activating agent was found to generate carbon with the highest porosity and surface area [14]. these results were in agreement with those of yuningsih et al. in the activation of corn cobs and coconut shell carbon with koh where surface area or pores volume increased with increase in koh concentration [29]; tetra et al. who observed that the ability of activated carbon to store an electrical charge will increase as the surface area of activated carbon increases [30]. the experimental data and analysis were checked by one-way anova to determine the effect of koh concentration on the dielectric properties of activated carbon derived from water hyacinth. based on the one-way anova test, the results obtained pvalue (sig) <0.05, which means ho is rejected, meaning that there is an effect of varying the concentration of koh activator in the process of synthesizing activated carbon derived from water hyacinth to the value of the dielectric constant. figure 2. the dielectric constant of activated carbon derived from water hyacinth using koh as activating agent iodine sorption value (isv) the effects of varying the concentrations of the activating agent (koh) on the iodine number of the chemically activated carbon derived from water hyacinth are shown in figure 3. figure 3 showed that the iodine number increased with increasing concentration of activator. the results 43 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 of the iodine number of activated carbon derived from water hyacinth with a concentration of 35wt% koh shows the highest iodine sorption value of 514.6 mg/g, while the concentration of 30wt% koh was 477.8 mg/g and the lowest iodine number was with a concentration of 25wt% koh of 409.5 mg/g. the increase in the iodine number was due to increase in pore formation and hence adsorptive capacity of the activated carbon as impregnation increased. the iodine number is defined as the milligrams of iodine adsorbed by one gram of carbon when the iodine residual concentration of the filtrate is 0.02n (0.01 mol/l) according to astm d4607 standard, which is based on a threepoint isotherm. hence it is a measure of the iodine adsorbed in the pores of the activated carbon and an indication of the pore volume available in the activated carbon. therefore, the carbon should be activated at concentration that gives the highest iodine value [31]. figure 3. effect of concentration of koh as activating agent on iodine number of activated carbon derived from water hyacinth conclusions from this experiment, activated carbon derived from water hyacinth in various concentration koh activator in term of the dielectric properties and iodine sorption value have been investigated. it has been seen that the increase concentration of koh in the process of synthesizing activated carbon causes increasing the dielectric constant and iodine number. in addition, optimum activated carbon derived from water hyacinth was obtained when the value of the dielectric constant was minimum and the value of iodine number was maximum. the dielectric constant minimum when concentration of 25wt% koh was 2.78 ± 0.18, meanwhile iodine number maximum when concentration of 35wt% koh was 514.6 mg/g. based on the results obtained, it is known that the dielectric properties and iodine sorption value from activated carbon can be used according to theirs application later. 44 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 acknowledgements we would like to express our gratitude to hibah keris in 2020 from lp2m university of jember for all the support provided. references [1] k.s. ukanwa, k. patchigolla, r. sakrabani, e. anthony and s. mandavgane, 2019, a review of chemicals to produce activated carbon from agricaltural waste biomass, sustainability, volume 11, page 1 – 35. [2] s. sukarni, y. zakaria, s.sumarli, r. wulandari, a.a. permanasari and m. suhermanto, 2019, physical and chemical properties of water hyacinth (eichhornia crassipes) as a sustainable biofuel feedstock, iop conf. series: materials science and engineering, volume 515, page 012070 – 012077. [3] k.o. sanni and j.m. adesina, 2011, utilization of water hyacinth (eichhornia crassipies mart solms) as liquid fertilizer on the growth and yield of fluted pumpkin (telfairia occidentalis), south asian journal of experimental biology, volume 2, no. 1, page 33 – 37. [4] g.a. vasconcelos, r.m.l. veras, j.l. silva, d.b. cardoso, p.c. soares, n.n.g. morals and a.c. souza, 2016, effect of water hyacinth (eichhornia crassipes) hay inclusion in the diets of sheep, trop anim health prod, volume 48, page 539 – 544. [5] w. rahmawati, a. haryanto and s. suharyatun, 2018, development of biodegradable board using water hyacinth (eichornia crassipes), international journal of environment, agriculture and biotechnology, volume 3, no. 1, page 170 – 174. [6] k. munjeri, s. ziuku, h. maganga, b. siachingoma, s. ndlovu, 2016, on the potential of water hyacinth as a biomass briquette for heating applications, international journal of energy and environmental engineering, volume 7, page 37 – 43. [7] s.m. gawande, a.a. mane and n.s. belwalkar, 2017, experimental study of activated carbon derived from dried water hyacinth and its performance in phosphate removal from wastewater, international journal of current research, volume 9, no. 7, page 53514 – 53517. [8] w. maulina, r. kusumaningtyas, z. rachmawati, supriyadi, a. arkundato, l. rohman and e. purwandari, 2019, carbonization process of water hyacinth as an alternative renewable energy material for biomass cook stoves applications, iop conf. series: earth and environmental science, volume 239, page 012035 – 012042. [9] v.k. guna, m. ilangovan, a.m. gangadharaiah and n. reddy, 2017, water hyacinth: a unique source for sustainable materials and products, acs sustainable chemistry and engineering, page 1 – 50. [10] i.m. siaka, n.p.d. febriyanti, e. sahara, i.m.s. negara, 2016, pembuatan dan karakterisasi arang dari batang tanaman gumitir (tagetes erecta) pada berbagai suhu 45 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 dan waktu pirolisis, cakra kimia indonesian e-journal of applied chemistry, volume 4, no. 2, page 168 – 177. [11] f.f. polii, 2017, effects of activation temperature and duration time on the quality of the active charcoal of coconut wood, journal of plantation based industry, volume 12, no. 2, page 21 – 28. [12] m. lempang, 2014, pembuatan dan kegunaan arang aktif, info teknis eboni, volume 11, no. 2, page 65 – 80. [13] a.h. surest, j.a.f. kasih and a. wisanti, 2008, pengaruh suhu, konsentrasi zat aktivator dan waktu aktivasi terhadap daya serap karbon aktif dari tempurung kemiri, jurnal teknik kimia, volume 15, no. 2, page 17 – 22. [14] h. xia, j. wu, c. srinivasakannan, j. peng and l. zhang, 2015, effect of activiting agent on the preparation of bamboo-based high surface area activated carbon by microwave heating, high temperature materials and processes, volume 35, no. 6, page 1 – 7. [15] k. hwa-young, p. sang-sook and r. yu-sup, 2006, preparation of activated carbon from paper mill sludge by koh-activation, korean journal of chemical and engineering, volume 23, no. 6, page 948 – 953. [16] h.m. yang, d.h. zhang, y. chen, m.j. ran and j.c. gu, 2017, study on the application of koh to produce activated carbon to realize the utilization of distiller’s grains, iop conference series: earth and environmental science, volume 69, page 012051 – 012058. [17] t. pagketanang, a. artnaseaw, p. wongwicha and m. thabuot, 2015, microporous activated carbon from koh-activation of rubber seed-shells for application in capacitor electrode, energy procedia, volume 79, page 651 – 656. [18] j. jin-young and l. young-seak, 2018, electrochemical properties of koh-activated lyocell-based carbon fibers for edlcs, carbon letters, volume 27, page 112 – 116. [19] a. wang and d.d.l. chung, 2014, dielectric and electrical conduction behavior of carbon paste electrochemical electrodes, with decoupling of carbon, electrolyte and interface contributions, carbon, volume 72, page 135 – 151. [20] t.s. hui and m.a.a. zaini, 2015, potassium hydroxide activation of activated carbon: a commentary, carbon letters, volume 16, no. 4, page 275 – 280. [21] z. heidarinejad, m.h. dehghani, m. heidari, g. javedan, i. ali and m. sillanpaa, 2020, methods for preparation and activation of activated carbon: a review, environmental chemistry letters, volume 18, page 393 – 415. [22] c.g. joseph, h.f.m. zain and s.f. dek, 2006, treatment of landfill leachate in kayu madang, sabah: textural and physical characterization (part 1), malaysia journal of analytical sciences, volume 10, no. 1, page 1 – 6. 46 computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1, page 38-46 submitted : february 8, 2020 accepted : april 20, 2020 online : may 2, 2020 doi : 10.19184/cerimre.v3i1.26417 [23] s.o. nelson, 1999, dielectric properties measurement techniques and applications, american society of agricultural engineers, volume 42, no.2, page 523 – 529. [24] t.t. grove, m.f. masters and r.e. miers, 2005, determining dielectric constants using a parallel plate capacitor, american journal of physics, volume 73, no. 1, page 52– 56. [25] m.a. bedmohata, a.r. chaudhari, s.p. singh and m.d. choudhary, 2015, adsorption capacity of activated carbon prepared by chemical activation of lignin for the removal of methylene blue dye, international journal of advanced research in chemical science, volume 2, no. 8, page 1 – 13. [26] l.e. laos and a. selan, 2016, pemanfaatan kulit singkong sebagai bahan baku karbon aktif, jurnal ilmu pendidikan fisika, volume 1, no. 1, page 32 – 36. [27] s.n. ab jabal, y.b. seok and w.f. hoon, 2016, carbon composition, surface porosities and dielectric properties of coconut shell powder and coconut shell activated carbon composites, arpn journal of engineering and applied sciences, volume 11, no. 6, page 3832 – 3837. [28] n. alias, m.j. kamaruddin and m.a.a. zaini, 2017, dielectric properties of sodium hydroxide-impregnated and activated cempedak peel samples at microwave frequencies, chemical engineering transactions, volume 56, page 931 – 936. [29] l.m. yuningsih, d. mulyadi and a.j. kurnia, 2016, pengaruh aktivasi arang aktif dari tongkol jagung dan tempurung kelapa terhadap luas permukaan dan daya jerap iodin, jurnal kimia valensi: jurnal penelitian dan pengembangan ilmu kimia, volume 2, no. 1, page 30 – 34. [30] o.n. tetra, h. aziz, syukri, b. arifin and a. novia, 2018, the effect of addition of activated carbons from peat on performance of supercapacitor base of activated carbon of palm kernel shell, jurnal zarah, volume 6, no. 2, page 47 – 52. [31] akpa, j.g. dagde and k. kekpugile, 2018, effect of activation method and agent on the characterization of prewinkle shell activated carbon, chemical and process engineering research, volume 56, page 24 – 36. iii computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2 november – 2019 editor in chief artoto arkundato editor lutfi rohman wenny maulina yoyok yulianto joko iswanto computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index iii computational and experimental research in materials and renewable energy (cerimre) volume 3, issue 1 may – 2020 editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah wenny maulina yoyok yulianto joko iswanto computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index cerimre https://jurnal.unej.ac.id/index.php/cerimre physics department, faculty of mathematics and natural sciences the university of jember volume 2, issue 2 november 2019 table of contents volume 2, issue 2 november – 2019 page cover i table of contents ii editorial board iii optimation of layers thickness design of perovskite solar cell (psc) using gpvdm simulation dita puspita 56-63 study of neptunium, americium and protactinium addition for 300mwth gfr with uranium carbide fuel ratna dewi syarifah and alvi nur sabrina 64-71 effects of intrinsic layer thickness on the short-circuit current density of crystalline silicon-based solar cells imroatus soleha, endhah purwandari and endang haryati 72-80 effect of angle of attack on pressure and lift coefficient of onera oa206 wing model using computational fluid dynamics method resti anggraeni 81-97 magnetic susceptibility of ferromagnetic alloy material co(1-x)ni(x) nanocube and nanosphere models imam wahyudi, lutfi rohman and endhah purwandari 98-105 cerimre https://jurnal.unej.ac.id/index.php/cerimre physics department, faculty of mathematics and natural sciences the university of jember volume 3, issue 1 may 2020 table of contents volume 3, issue 1 may – 2020 page cover i table of contents ii editorial board iii protein adsorption on modified bacterial cellulose bambang piluharto, fitri sulistyowati, dwi indarti, busroni and d. setiawan purwo handoko 1-9 study of the ferromagnetic magnetite resonance (fe3o4) forms of thin films using micromagnetic simulation syefira salsabila, lutfi rohman and endhah purwandari 10-18 design study of gas cooled fast reactor (gfr) with uranium plutonium carbide (uc-puc) as fuel with addition protactinium (pa-231) alvi nur sabrina, arindi kumala sari, laela nur janah and m. rizqi maulana 19-26 study of j-v characteristics of microcrystalline silicon solar cell on the structure of p-i-n homojunction yuningtyas nely kusuma dewi, endhah purwandari, khoirul anwar and misto 27-37 study of dielectric and adsorption properties of activated carbon prepared from water hyacinth using koh as an activating agent mochammad ghiffari, wenny maulina and agung tjahjo nugroho 38-46 45 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 modeling of ferrous metal diffusion in liquid lead using molecular dynamics simulation ahmad anwar nuris 1,a 1 berka semi strategika, kpp ipb baranangsiang iv blok a/35 tanah baru, bogor utara, kodya bogor, bogor 16154, indonesia a al.adrislamic@gmail.com abstract. modeling of iron metal diffusion in liquid lead using molecular dynamics simulation has been done. molecular dynamics simulations are used to predict the value of physical quantities that we want to know based on the designed material model and on the input simulation data. in this research, effect of different geometry of material models was observed to know the diffusion coefficient. the material system was iron (fe) in liquid lead (pb). the material models is designed using packmol software to get the initial configuration of atom's arrangement by inputting the material's characteristics such as mass, density, volume, number of atoms. this work examines the diffusion coefficient of iron in molten lead metal with the geometric shape of the simulation system in the form of iron in molten metal for various simulation models of boxes in a box, balls in a box and balls in balls. to design simulated geometric shapes we use the packmol program. to calculate the diffusion coefficient we use the molecular dynamics simulation method. to find out which geometry is suitable, we compare the diffusion coefficient of the simulation results with existing references. the diffusion coefficient value of the spherical iron (fe) system in the spherical liquid lead (pb) has the best value compared to the other two forms with an accuracy rate of 99.94% because it is influenced by the even distribution of atoms in each part. keywords: lammps, molecular dynamics, fe-pb, packmol, mean square displacement introduction computation is an activity to obtain a solution of complex problems following a certain mathematical model [1]. computer simulation is a tool for studying macroscopic systems by applying microscopic models, especially for prediction of materials properties [2]. one example of research using computer simulations is the prediction of diffusion coefficient of materials that is important data for many applications. knowing the diffusion coefficient can help us to study the corrosion phenomena as in the field of nuclear reactor design [3,4]. there have been many corrosion experiments in search of superior steel for nuclear applications and determining the appropriate method for corrosion inhibition [5]. the high cost of installation for corrosion experiments and the need for a high safety level is the main constraints today. this is because the metal vapor produced is very toxic, and also, not all experiments can be carried out in an operating reactor. particularly in indonesia, this activity seems not possible due to inadequate facilities [6]. therefore, computation and simulation methods are solutions to overcome these obstacles. one of the computational studies conducted is to use the molecular dynamics method [7-9]. when examining the corrosion of steel materials in the fast reactor, ferrous metal is the largest steel composition element. at the same time, molten lead is a suitable material as a coolant for 46 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 sodium substitute rector. the most relevant property of lead is the massive difference between its melting and boiling points. the boiling and melting points of lead are 601k and 2022k respectively. these properties lead to higher reliability and safety for the reactor installation than the use of sodium [10]. the diffusion coefficient is obtained with a high degree of accuracy when compared with the experimental results. this study using packmol software for preparing the configuration of coordinate x, y, and z of the atoms of materials. the initial configuration of the arrangement of iron (fe) and lead (pb) atoms from packmol will be running in lammps (large scale atomic / molecular massively parallel simulator: lammps.sandia.gov), an open-source software that has the advantage of being able to run large-scale computing. with the number of atoms up to millions of grains. lammps software is also widely used for material simulation. this can be seen from the number of journal articles published from the results of lammps-based computational research. also, this software is always updated [7]. in this study, calculations were carried out to determine the best mean square displacement (msd) value in the variation of the simulation system model for ferrous metal (fe) in the liquid lead (pb) obtained when calculated using the molecular dynamics software lammps. and to find out the value of the diffusion coefficient (d), which is the best in the variation of the system model of iron (fe) in the liquid lead (pb) obtained when calculated using the molecular dynamics software lammps. theoretical background the interaction model between molecules needed in the simulation is the law of intermolecular force, which is equivalent to the potential energy function between molecules. the selection of the potential energy function must be made before any simulation is carried out. the choice of the interaction model between molecules greatly determines simulation correctness from a physics point of view. because they are on the atomic scale, interactions must, in principle, be derived quantum, which is where the heisenberg uncertainty principle applies. however, a classical mechanical approach can be used where the atom or molecule is considered a point mass [11]. for n, the number of atoms in a simulation, the potential energy function is u(r n ), where r n is the set position of the center of mass of the atom or molecule, r n = {r1, r2, r3,…. rn} which can be expressed as: (1) potential energy is the sum of the interactions between two isolated molecules [12]. there are potential energy models used in molecular dynamics simulations, including the lennard-jones potential. this model's use in the simulation provides a reasonably good level of accuracy in describing the interactions between atoms. the main characteristic of lennardjones is that it is very responsive for small r and less attractive for large r [13]. these characteristics can be seen in the image below: 47 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 figure 1. the atomic interaction model with the lennard-jones potential (a) repulsive (b) attractive [14] this potential model equation can be formulated: (2) n and m are positive integers selected n>m, and i, j are the molecule indices, rij = |ri-rj| or the distance between molecules i and j. whereas σ is the distance parameter, and ε is the parameter that states the interaction's strength. k is the coefficient obtained from the equation: (3) common choices for m and n are m = 6 and n = 12 [15]. so that we get the equation: (4) the lennard-jones potential can be used to determine the characteristics of gases, liquids, clusters, and polycrystalline materials [16]. the lennard-jones potential for molecular dynamics simulations has parameters that can be taken from experimental data. materials and methods 1. preparation of simulation inputs based on the flow diagram in the simulation input preparation step, the run's initial simulation is a system consisting of iron (fe) in the molten lead (pb). the iron metal being modeled consists of 3527 atoms and 8000 metal atoms of lead (pb). the temperature used is 1023 k or 750 o c because it is at this temperature that w. m. robertson experimented calculating the diffusion coefficient of iron in the pure lead. the diffusion coefficient value from the experimental results is 2.8 x 10-9 m 2 /s [17]. the density of the system is calculated using the temperature-dependent density equation, as shown by equation 5 with t in kelvin [18]. (5) 48 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 2. determination of the diffusion coefficient (d) determination of the diffusion coefficient (d) of ferrous metal (fe) can be seen from the data output of simulation from the mean square displacement (msd) in the format (.txt), which can be processed using microsoft office excel. the msd value data for iron metal (fe) is represented in graphical form against simulation time. the diffusion coefficient d value is obtained from the gradient graph of the relationship between the msd value and the simulation time. after the diffusion coefficient d value of the simulation results is determined, it can be compared with the diffusion coefficient d value of the experimental results so that the simulation results' accuracy level can be seen. results and discussion the simulation using the molecular dynamics method basically begins by determining the atoms of the material being studied, namely the iron atoms and the lead atoms. the arrangement of the atomic configuration is made after calculating the volume of the system to be made. calculation of the iron and liquid lead atoms' volume size is carried out using the services (utilities) available on the packmol website. the data input provided includes the density of the molecular mass to be made, the number of atoms contained in the molecule, and the molar mass of these atoms. the simulation system made in this study is iron (fe) in the form of a cube with bcc structure in the lead (pb) in the form of a cube. this system consists of 3527 iron (fe) atoms and 8000 lead (pb) atoms. the visualization of this configuration can be seen in figure 2 of the following page. figure 2. (a) cube-shaped iron (fe) with the structure of bcc in liquid lead (pb) in the form of a cube visualized with ovito software, (b) cubic iron (fe) with the structure of bcc in liquid lead (pb) in the form of a cube visualized with ovito with add modification slice 49 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 figure 3. (a) spherical iron (fe) with a bcc structure in the liquid lead (pb) in the form of a cube visualized with ovito software, (b) spherical iron (fe) with a bcc structure in the liquid lead (pb) in a cuboid visualized with ovito with the add modification slice. besides that, a spherical iron (fe) simulation system with the structure of bcc in the lead (pb) is also constructed, consisting of 3527 iron atoms (fe) and 8000 lead atoms (pb). visualization of a spherical iron (fe) system with a bcc inside structure cuboid of lead (pb) is shown in figure 3. while the third simulation system created is a system of 3527 iron atoms (fe) with a bcc structure in the form of a ball in a spherical liquid lead (pb) consisting of 8000 atoms. figure 4. (a) spherical iron (fe) with the structure of bcc in the liquid lead (pb) in the form of a sphere visualized by ovito software, (b) spherical iron (fe) with the structure of bcc in the liquid lead (pb) in the form of a ball visualized with ovito with add modification slice figure 4 is a visualization of a spherical iron (fe) system with bcc structure in the spherical lead (pb). these three systems are designed to determine the simulation system's ideal form in the simulation process of the iron (fe) system in the liquid lead (pb). the determination of ideal is based on the most diffusion coefficient's value closer to the experimental results. mean square displacement (msd) system of iron (fe) in liquid lead (pb) the diffusion process can affect the crystal structure of a material. even diffusion can cause crystal defects. in the diffusion process, there is also the movement of atoms to change their position. each atom that undergoes movement, then the atom has the average square of the atomic movement, commonly referred to as msd (mean square displacement). the msd simulation results from lammps against the simulation time are in the form of msd value data in the format (.txt), which can be processed using microsoft office excel. the msd relationship curve to the simulation time of the iron (fe) system in the liquid lead (pb) is shown 50 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 in figure 5. in the curve shown in figure 4.8, it can be seen that the msd value ranges of three different crystal forms. figure 5. the curve of the mean square displacement (msd) relationship with the simulation time of the iron (fe) system in the liquid lead (pb) the blue curve shows the simulation results of the iron (fe) system in the form of a cuboid with bcc structure in the liquid lead (pb) in the form of a cube, the red curve shows the simulation results of the spherical iron (fe) system with the structure of bcc in the liquid lead (pb) in the form of a cube. the green curve shows a spherical iron (fe) system with bcc structure in the spherical liquid lead (pb). in the curve shown in figure 4, it can also be seen that the msd value of the spherical iron (fe) system in the liquid lead (pb) has the highest value compared to the other two forms. the nonlinearity at the start is typical of the msd curve. this is because the atom has not yet interacted with other atoms. after the nonlinear section at the start of the curve, it is followed by a straight line. the higher the slope of the msd curve, the more random the atomic arrangement is. meanwhile, the slope of the msd curve is directly proportional to the diffusion constant of a material. diffusion coefficient (d) of the iron (fe) system in liquid lead (pb) the diffusion coefficient can be said to be the most precise physical quantity known from a system. when a system gets disturbed by the influence of the environment, it can cause the movement of the atoms that make up the system randomly so that the coefficients in the system can be known. the movement of the atoms that make up the system can produce atomic trajectories. the atomic trajectories can represent each atom's positions so that each of these atomic positions can cause an interaction force between atoms. according to newton's law, potential energy is a negative gradient of the interaction force, so from the interaction force between atoms, it can be seen the potential energy between atoms. as explained in the paragraph above, the determination of the diffusion coefficient value of a system made for simulation is also influenced by the potential models used. the potential models used are the lennard-jones potential. this potential is recommended for use in a simulation system of iron (fe) in the liquid lead (pb) from the previous studies. the lennard jones potential has two parameters, namely the distance parameter and the energy parameter. cubic fe in cubic liquid pb spherical fe in cubic liquid pb spherical fe in spherical liquid pb simulation time 51 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 these two parameters significantly affect the simulation results used. the distance parameter and the energy parameter have a value that varies from one atom to another. this lennard jones potential will also be an input in the simulation process using the lammps software. the simulation results of the diffusion coefficient value can be shown in table 1. the most significant diffusion coefficient value is obtained from the spherical iron (fe) system with bcc structure, in the liquid lead (pb) in the form of cubes, and the lowest is the spherical iron (fe) system with bcc structure, in the liquid lead (pb) in the form of a sphere. this shows that the diffusion coefficient is linear with the msd calculation results. table 1. diffusion coefficient in the iron (fe) system in liquid lead (pb) crystal shape coefficient (m2/s) accuracy cubic fe in cubic liquid pb 2.91155x 10 -9 96.02% spherical fe in cubic liquid pb 3.00955 x 10 -9 92.52% spherical fe in spherical liquid pb 2.79835 x 10 -9 99,94% based on table 1, it is also known that the accuracy value in the spherical iron (fe) system with bcc structure in the liquid lead (pb) in the form of a ball is higher than the other two systems. the simulation accuracy level can be determined by comparing the calculation results of the simulation with the experimental results. w. m. robertson has carried out experiments to calculate the diffusion coefficient of iron in the pure lead. the experimental results' coefficient value is 2.8 x 10-9 m 2 /s [13]. thus, the spherical shape is an ideal form of a simulation system for simulating liquid iron (fe) in lead (pb) systems. this is because the shape of the iron (fe) simulation system model in the spherical liquid lead (pb) provides better accuracy values than other forms. based on table 1, it can also be seen that the forms of simulation system models made on the iron (fe) system in the liquid lead (pb) have an effect on the msd value. this also impacts the diffusion coefficient value obtained because, in theory, the diffusion coefficient value is directly proportional to the msd. this is inseparable from the distribution of the atoms in each part of the system. the lowest accuracy value is obtained from the spherical iron (fe) system with a bcc structure in the liquid lead (pb) in the form of cubes. this is because the lead (pb) atoms in this system are not evenly distributed in certain parts. the number of lead (pb) atoms is greater than the side direction in the corner direction. based on table 2 it is known the number of atomic distributions in each part of the simulation system. table 2. comparison of atomic distribution in iron (fe) system in liquid lead (pb) crystal form number of atomic distribution in the corner on the side cubic fe in cubic liquid pb 268 194 spherical fe in cubic liquid pb 308 202 spherical fe in spherical liquid pb 259 238 this can be seen from the visualization results on ovito, which is shown in the image below. 52 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 figure 6. spherical iron (fe) with a bcc structure in the liquid lead (pb) in the form of a cubic visualized with ovito with an add-on modification slice figure 6 shows the distance between the corner points of the cube and the outer side of the sphere as labeled with (α) has a longer distance than the distance between the cube's side and the outer side of the sphere labeled with (β). based on this distance factor and the number of atomic distribution causes the interaction force between the atoms to be uneven from each side of the system is created. the accuracy value of the cube-shaped iron (fe) system with bcc structure in the liquid lead (pb) is better than the spherical iron (fe) system with bcc structure in the liquid lead (pb) in cubic form. figure 7. cubic iron (fe) with bcc structure in the liquid lead (pb) in cubic shape visualized with ovito with add modification slice figure 7 shows that the atomic distribution is better than the atomic distribution. this is because the number of atoms in the cube-shaped iron (fe) system with the bcc structure in the liquid lead (pb) is more evenly distributed. if we compare the two, it can be seen that the α / β ratio for a spherical system in a cube is more significant than that for a cube system in a cube. the most significant accuracy value is the ball in the ball model. because theoretically, the distribution of atoms and energy in the system is almost evenly distributed for each part. 53 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 figure 8. spherical iron (fe) with bcc structure in the liquid lead (pb) the ball was visualized with ovito with an add-on slice modification. this is also reinforced by the ovito visualization results, which shows the value of α = β, as shown in figure 7. the comparison of α and β distances for the three systems of iron (fe) in the liquid lead (pb) can be seen in table 3. table 3. comparison of α and β in the iron (fe) system in the liquid lead (pb) crystal form α (å) β (å) cubic fe in cubic liquid pb 30.14 26.10 spherical fe in cubic liquid pb 43.29 12.81 spherical fe in spherical liquid pb 18.69 18.69 based on table 3, the α / β ratio for the spherical system in a sphere is smaller than the cube system in a cube and the spherical system in a cube. in simple terms, the α / β ratio for the three systems can be denoted in the equation below. (6) where α is the angular distance of the liquid lead (pb) from the outer side of the iron (fe), and β is the angular distance of the liquid lead (pb) to the outer side of the iron (fe). conclusions based on the research that has been done, it can be concluded that, first, making the ideal molecular dynamics simulation system for the iron (fe) system in the liquid lead (pb) begins by calculating the volume of the system made, namely iron (fe) in the liquid lead (pb) by ensuring that the mass density value is maintained. the mass density must also be calculated using the temperature-dependent density equation so that the simulation results can be close to the experimental results. these data become the basis for making the initial configuration. the initial configuration in the form of x, y, z coordinates is made using credible software, one of which is packmol. second, the mean square displacement (msd) value of the spherical iron (fe) simulation system in the spherical liquid lead (pb) has the best value compared to the other two forms. third, the spherical iron (fe) system's diffusion coefficient value in the spherical liquid lead (pb) has the best value compared to the other two forms with an accuracy rate of 99.94% because it is influenced by the even distribution of atoms in each part. 54 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 references [1] warsito, 2005, komputasi tomografi dan aplikasinya dalam proses industri, ohio: departement of chemical engineering the ohio state university. [2] d. frenkel and b. smit, 2002, understanding molecular simulation, second edition. london: academic press. [3] r. d. syarifah, z. su’ud, k. basar, d. irwanto, s. c. pattipawaej and m ilham, 2017, comparison of uranium and thorium nitride fuel for 500mwth gas cooled fast reactor (gfr) longlife without refueling, international journal of energy research, special issue paper, page 1-7. [4] r. d. syarifah, z. su’ud, k. basar and d. irwanto, 2016, the prospect of uranium nitride (un-pun) fuel for 25-100mwe gas cooled fast reactor long life without refuelling, journal of physics: conference series 776 012103, page 1-5. [5] takaya, 2009, the corrosion behavior of al-alloying high cr-ods steels in the lead-bismuth eutectic, journal of nuclear materials 386–388, page 507–510. [6] a. maulana, 2006, aplikasi paket program moldy untuk karakterisasi sifat bahan fe, pb, bi dan pendingin reaktor pb-bi, risalah lokakarya komputasi dalam sains dan teknologi nuklir xvii, page 119-130. 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[12] a. witoelar, 2002, perancangan dan analisa simulasi dinamika molekul ensemble mikrokanonikal dan kanonikal dengan potensial lennard jones, tugas akhir, bandung: institut teknologi bandung. 55 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 45 – 55 submitted : february 2, 2019 accepted : april 5, 2019 online : mei 2, 2019 doi : 10.19184/cerimre.v2i1.20561 [13] h. gould, j. tobochnik and w. cristian, 2007, an introduction to computer simulation methods: application to physical systems, third edition, boston: addison-wesley longman publishing. [14] a. arkundato, 2012, studi penghambatan korosi logam besi dalam lingkungan pendingin reaktor cepat berbahan pb dan pbbi cair dengan menggunakan metode somulasi dinamika molekul, disertasi. bandung: institut teknologi bandung. [15] b. n. wira and a. rian, 2012, simulasi sifat fisis model molekuler dinamik gas argon dengan potensial lennard-jone, makassar: jurusan fisika fmipa universitas hasanuddin. [16] a. m. krivtsov and m wiercigroch, 2002, molecular dynamics simulation of mechanical properties for polycrytal materials, mater. phys. mech., volume 3, page 45-51. [17] a. arkundanto, 2013, study of liquid lead corrosion of fast nuclear reactor and its mitigation by using molecular dynamics method. international journal ofapplied physics and mathematics. [18] a. d. kirshenbaum, j. a. cahill and a. v. grosse, 1961, the density of liquid lead from the melting, journal of inorganic and nuclear chemistry, volume 22, page 33–38. iii computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1 november – 2021 eissn 2747-173x editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah wenny maulina yoyok yulianto muhayat zamroni wiwin ro’inah computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index cerimre https://jurnal.unej.ac.id/index.php/cerimre eissn: 2747-173x physics department, faculty of mathematics and natural sciences the university of jember volume 4, issue 2 november 2021 table of contents volume 4, issue 2 november – 2021 eissn 2747-173x page cover i table of contents ii editorial board iii neutronic analysis of the smart modular reactor fuel using srac 2006 nailatussaadah and irsyad 60-70 the study of the electrical conductivity and activation energy on conductive polymer materials balqyz lovelila hermansyah azari, totok wicaksono, jihan febryan damayanti, dheananda fyora hermansyah azari 71-79 lift force of airfoil (naca 0012, naca 4612, naca 6612) with variation of angle of attack and camber: computational fluid dynamics study mariza d. ardany, paken pandiangan and moh. hasan 80-93 study of electronic properties of gaas semiconductor using density functional theory fikri abdi putra, endhah purwandari and bintoro s. nugroho 94-101 the effect of arrive angle of external magnetic field on the shape of hysteresis curve permalloy ni80fe20 by simulation merinda lestari, widia nursiyanto, and agung tjahjo nugroho 102-109 8 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 neutronic analysis of leu-started molten chloride fast reactor without fuel reprocessing r. andika putra dwijayanto 1,2,a and andang widi harto 1 1 department of nuclear engineering and physics engineering, universitas gadjah mada, jl. grafika no. 2, yogyakarta, indonesia 55281 2 centre for nuclear reactor technology and safety, national nuclear energy agency, building no. 80 puspiptek area, south tangerang, indonesia 15310 a putra-dwijayanto@batan.go.id abstract. one of the rarely explored molten salt reactor (msr) designs is the molten chloride fast reactor (mcfr). this msr design employs chloride salt instead of fluoride and operated in a fast spectrum. mcfr brings all the advantages of an msr including breeding whilst being able to burn plutonium and minor actinides efficiently. since not many countries have access to civilian plutonium, mcfr can also be started using low-enriched uranium (leu). this study is an initial neutronic analysis of an mcfr using leu as its startup fuel. parameters analyzed are conversion ratio (cr) and its neutronic safety, namely effective delayed neutron fraction (βeff), temperature coefficient of reactivity (tcr), and void coefficient of reactivity (vcr). the core is divided into core zone and blanket zone. the fuel composition of nacl-ucl3 with a molar fraction ratio of 60:40 and 50:50 is used in core zone and blanket zone, respectively. the neutronic calculation is performed using mcnp6 code with endf/b-vii library. for reference geometry, cr is valued at 0.9298, βeff at 0.00731, tcr at -19.8 pcm/°c, and average vcr at -154.31 pcm/void%. thereby, the mcfr fulfills inherent safety criteria. although its value is remarkably high, cr can be further optimized by modifying the separator and reflector material. keywords: mcfr, conversion ratio, effectively delayed neutron fraction, temperature coefficient of reactivity, void coefficient of reactivity introduction molten salt reactor (msr) is a general term for any reactor that uses liquid fuel in a salt-bound compound. fissile and fertile fuel, either uranium, thorium, or plutonium, is dissolved within a molten carrier salt such as fluoride salt and chloride salt. the liquid fuel acts both as fuel and coolant, and the fuel is circulating the primary system instead of static [1–3]. as a liquid-fuelled reactor, msr offers many advantages compared to conventional light water reactors. among them are [1–5],  atmospheric operational pressure due to high boiling point of salt, eliminating the need of pressure vessel.  operability in high temperature (700 °c and higher).  high coefficient of thermal expansion, which provides negative temperature reactivity coefficient.  no possibility of hydrogen explosion due to the absence of water in the primary loop.  no fuel fabrication is required, which drives down fuel cost and increasing neutron economy due to lower parasitic capture. 9 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962  salt is highly radiation damage-resistant, thus allowing the fuel to stay indefinitely in the core and attaining high burnup.  possible online fuel reprocessing to remove fission products and actinides, allowing thermal breeding for msr utilizing thorium fuel cycle. msr is offered in various designs; moderated [4,6–10] or unmoderated [11–16], fluoride or chloride, thorium or uranium. most msr researches and designs favor thermal msr, leaving only a handful of designs of fast msrs, such as french msfr [11], terrapower’s mcfr [17], and elysium industries’ mcsfr [18]. whilst msfr is intensively researched, little to no details surrounding the latter two. coincidentally, those obscure designs are categorized into molten chloride fast reactors (mcfrs). among possible msr designs, mcfr is one of the least explored. it employs chloride salt instead of fluoride salt [19,20]. chloride provides a harder neutron spectrum, and thus more suitable for uranium-plutonium (u-pu) cycle [21]. chloride salt can dissolve a higher fraction of plutonium and minor actinide (ma) compared to fluoride salt [15,22,23]. mcfr runs with sodium chloride as its coolant, avoiding the requirement of highly enriched lithium-7 in fluoride salt. researches in msfr show that fast msr requires less fuel processing thanks to higher neutron economy [11], and mcfr is likely to show similar characteristic. those aforementioned characteristics make mcfr an interesting design for uranium utilization and ma burning. mcfr can be used to incinerate both military and civilian plutonium along with ma whilst being self-sustaining. for countries with no access to plutonium, mcfr can be started using leu and gradually transition into equilibrium u-pu core. owing to its excellent neutron economy, the u-pu mcfr core is potentially suitable to breed u-233 from thorium on its blanket. despite the features, it offers, researches regarding mcfr is quite scarce. thus, mcfr performance is barely understood, including the extent of its safety characteristics. this research is performed as an initial study on the neutronic performance of an mcfr started with leu. the fuel is chosen as it is the most widely available fissile fuel, and thus more likely to be used in countries that own no pu. as an initial study, the parameters calculated are conversion ratio (cr) along with neutronic safety parameters such as effectively delayed neutron fraction (βeff), temperature coefficient of reactivity (tcr), and void coefficient of reactivity (vcr). the calculation is performed using mcnp6 radiation transport code with endf/b-vii continuous neutron library. general description most mcfr designs opted for cylindrical core [17–20,23]. at the time this paper is written, it is unknown whether elysium industries' mcsfr employs a single zone or dual zone, whilst limited data regarding terrapower’s shows that it employs a single zone [17]. mcfr assessed in sinap uses dual-zone, separating the fissile and fertile zone [23]. stable salt reactor (ssr), another design using chloride salt, is a static-fuelled msr with separate fuel and coolant salt [15,22]. mcfr design in this study was adapted from rebus [21], and thereby separate core and blanket zone are used. this configuration is similarly used by chinese mcfr. the core zone is a hollow cylinder surrounded by a blanket zone; each zone is separated by a separator material. the diameter and height of the core are equal. the fluid fuel enters the core 10 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 zone from the bottom, heated by fission inside the core, and exits the core at the top. the heat is then transferred to the secondary salt loop before the cooled salt re-enters the core. fertileonly blanket zone surrounds the core with a thickness of 50 cm on the radial region and 25 cm on the axial regions. the core and blanket are separated by a 10-cm thick separator. reflector material is placed surrounding both core and blanket zones, and further enclosed by stainless steel core shroud. understanding the harsh nature of a fast reactor, the whole core components are not expected to last for dozens of years but are designed to be easily replaced after a few years of operation. the graphical design of mcfr core is provided in figure 1. (a) (b) figure 1. mcnp model of mcfr core (a) axial view, (b) radial view the most distinctive difference between mcfr and thermal msr is the utilization of chloride salt instead of fluoride. chloride is a poor neutron moderator compared to fluoride and thereby provides a harder spectrum. it benefits the most in u-pu cycle, which allows a higher neutron economy and better breeding capability. as carrier salt, nacl is used in place of lif. to optimize breeding, cl-37 isotope is enriched to 99.95%. this way, parasitic absorption by cl-35, which proves to be obstructing the neutron economy and resulting in long-lived radioactive waste [23], can be minimized. chloride salt can dissolve a higher amount of actinide compared to fluoride salt. in this study, a nacl-ucl3 mixture with the molar proportion of 60%-40% for core zone and 50%-50% for blanket zone. low-enriched uranium (leu) is used in core zone, with the enrichment level is set below 20% limit to minimize fissile load whilst allowing higher fertile load, to enh ance breeding. higher fertile load in blanket zone is similarly intended to increase fissile breeding. uranium used in blanket zone has depleted uranium with 0.2wt% of fissile u-235. mcfr parameters used in this study are shown in table 1. table 1. mcfr core parameters parameters value thermal power (mwt) 3000 power density (mwt/m 3 ) 244 core diameter (cm) 250 core height (cm) 250 fuel salt composition (mol%) 60nacl—40(low-enriched)ucl3 11 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 parameters value fertile salt composition (mol%) 50nacl—50(depleted)ucl3 salt temperature (°c) 630 fuel salt density (g/cm 3 ) 4.22 fertile salt density (g/cm 3 ) 4.71 separator material graphite separator density (g/cm 3 ) 1.85 reflector material beo reflector density (g/cm 3 ) 3.01 core shroud material stainless steel core shroud density (g/cm 3 ) 7.98 materials and methods mcfr benefits from a hard neutron spectrum and better neutron economy, so the influence of neutron-absorbing fission products (fps) such as xe-135 and sm-149 is much less affecting reactor operation. the requirement of online reprocessing is also much smaller. in msfr, reprocessing is performed only for 40 liters/day, compared to 4.6 m3/day for msbr [11,24]. nevertheless, this study assumes batch reprocessing, considering that it is comparably simpler than online fuel reprocessing, and neutron economy requirement in u-pu cycle is less stringent than that of u-th cycle. the fuel is burned inside the core for a whole year, then the fps are extracted and fissile fuel bred from blanket zone is added into the core along with new fertile fuel. the calculation is performed using monte carlo n-particle version 6 (mcnp6) with endf/b-vii continuous neutron group library. kcode module is employed to calculate criticality. neutrons simulated per keff cycle are set at 10,000 for a total of 250 cycles, with the first 50 cycles are discarded. since this study omits online fuel reprocessing, sufficient excess reactivity is required to maintain criticality for each cycle, in this case, one year. various fuel enrichment levels will be assessed, but only those with keff slightly above unity are considered for burnup calculation. this is to keep excess reactivity as low as possible, to maintain reactor control with minimum reactivity control mechanism requirement. βeff value is calculated in mcnp6 using kopts card [25]. one distinguishing difference between msr and the conventional reactor is that msr fuel is constantly circulating. consequently, some fraction of βeff is "lost" from the core [26,27]. the real βeff value is lower from the value calculated by mcnp, which can range from 10% in msr-fuji to 40% in msbr case [28]. calculation of lost βeff is beyond the scope of this study so that the βeff value calculated is left as it is. tcr is calculated by varying the operational temperature from its operational temperature. criticality calculation is employed in temperatures of 600k, 900k, and 1200k. due to thermal expansion, fuel density is different for each temperature, and therefore adjusted accordingly. in msr system, fuel density change can be treated as void. thus, vcr in mcfr is calculated by lowering the density of fuel salt both in core zone and blanket zone. the density change is calculated for a void fraction of 0-50%. 12 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 mcfr started with leu is unable to breed. nevertheless, to minimize fissile fuel consumption and reducing the additional fissile requirement for the next cycle, the conversion ratio (cr) must be achieved as high as possible. cr value in this study is defined by the following equation. ∑ ∑ (1) burn-up calculation is performed by employing a built-in cinder90 depletion code. the irradiation time is set as 365 days with nominal power of 3000 mwt. results and discussion leu-started mcfr can be critical with minimum u-235 enrichment of 13.7wt%. usually, msr is kept critical with low excess reactivity, with keff below 1+β. mcfr employs batch reprocessing and batch refueling, thus higher excess reactivity is necessary. fuel enrichment is then varied at 13.7wt%, 13.75wt%, and 13.8wt%. the enrichment increase is not necessarily large since fast reactor is relatively more sensitive to fissile change in the reactor. the keff value at beginning of cycle (boc) and end of a cycle (eoc) with various fuel enrichment is presented in table 2. table 2. keff of mcfr at boc and eoc fuel enrichment keff reactivity swing (pcm) boc eoc 13.7wt% 1.00621 ± 0.00036 1.00147 ± 0.00036 470.38 13.75wt% 1.00779 ± 0.00039 1.00213 ± 0.00036 560.43 13.8wt% 1.00931 ± 0.00039 1.00347 ± 0.00036 576.61 it can be understood that fuel enrichment of 13.7wt% is sufficient to maintain criticality for one year. the value is satisfying in two terms. the first being a low reactivity swing, amounting of 470 pcm. part of the reason is the high conversion rate, which allows the reactor to stay critical for a longer time with minimum excess reactivity. higher enrichment resulted in higher reactivity swing, due to lower breeding or in situ consumption of pu-239 bred in the core. the second is that the initial keff is lower than its βeff, which is valued at 731 pcm. this will be further elaborated on later. cr value for each enrichment is calculated using equation 1. pu-239, pu-241 and np-239 are all calculated for cr. the latter is included since it will eventually beta-decay into pu-239. the mass balance of heavy metal at boc and eoc is given in table 3. table 3. mass balance of heavy metal and conversion ratio nuclide 13.7wt% 13.75wt% 13.8wt% mass at boc (kg) mass at eoc (kg) mass at boc (kg) mass at eoc (kg) mass at boc (kg) mass at eoc (kg) u-235 7,169.00 6,038.00 7,195.00 6,065.00 7,221.00 6,089.00 pu-239 core 659.70 656.70 656.60 blanket 374.30 374.20 373.20 13 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 nuclide 13.7wt% 13.75wt% 13.8wt% mass at boc (kg) mass at eoc (kg) mass at boc (kg) mass at eoc (kg) mass at boc (kg) mass at eoc (kg) pu-241 core 0.79 0.81 0.79 blanket 5.60 5.54 5.57 np-239 core 6.73 6.70 6.70 blanket 4.42 4.42 4.40 fissile lost 1,131.00 1,130.00 1,132.00 fissile gain 1,051.55 1,048.37 1,047.25 cr 0.9298 0.9278 0.9251 the maximum cr obtained is 0.9298. such value is remarkably high, knowing that the reactor is fuelled by u-235. about two-third of the plutonium is formed in fuel zone, with the rest formed in blanket zone. the high fertile fraction in blanket zone helped to enhance fissile breeding. since the cr is below unity, the reactor itself cannot be defined as a breeder. however, plutonium bred from blanket zone is supposed to be sufficient to self -sustain the mcfr without the addition of external u-235. this is due to the fact that plutonium performs better in fast spectrum than u-235, and thus reducing core critical mass. highly enriched cl-37 also helped in increasing cr. unenriched cl-37 has been proven to hinder the neutronic performance of mcfr, contributed by parasitic neutron capture by predominant cl-35. apart from reducing neutronic performance, high cl-35 content also resulted in large activation product cl-36, a long-lived radionuclide, as the waste. as well as corrosive sulfur. therefore, cl-37 enrichment is recommended in mcfr. neutron spectrum analysis is done only for 13.7wt% fuel enrichment. after irradiation, the neutron spectrum in core zone does not shift significantly. only slight softening is observed, as the fission products build up whilst pu-239 is yet to be the dominant fissile isotope. in boc, only around 8.74% of fission event occurs at thermal spectrum. the rest of fission occurs in the intermediate and fast spectrum, with approximately equal share. at eoc, thermal fission share increased to around 12.76%, reducing the intermediate and fast fission, thereby the spectrum softening. the neutron spectrum is displayed in figure 2. 14 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 (a) (b) figure 2. neutron spectrum of mcfr (a) core zone and (b) blanket zone using graphite as separator material reduced neutron energy when it enters blanket zone. this caused the spectrum to be softened compared to core zone, with the highest flux is considerably lower and located in the lower neutron energy zone. beo reflector may also induce neutron moderation, but its extent is currently unknown. from this finding, it can be concluded that using different separator and reflector material may result in different neutron spectrums, either hardening or softening, thereby affecting cr. thus, cr value can be further optimized by exploring the options of separator and reflector material. the next calculation is on neutronic safety. the calculation was performed only for mcfr core with leu enrichment of 13.7wt%. among the important neutronic safety, parameters are delayed effective neutron fraction (βeff), temperature coefficient of reactivity (tcr), and void coefficient of reactivity (vcr). βeff is an influential factor in determining reactor controllability. 15 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 low βeff usually necessitates tighter reactivity control, since the reactor period is shortened and the margin to prompt criticality is smaller. this is especially a challenge in a breeder reactor, since fissile pu-239 and u-233, the only two isotopes that are suitable for breeding, possess lower βeff than u-235 usually used in conventional reactors. βeff value shifts as the fissile u-235 is burnt and pu-239 is formed both in the core zone and blanket zone. the value at the boc and eoc is shown in table 2. table 2. βeff value at boc and eoc condition βeff boc 0.00731 ± 0.00072 eoc 0.00617 ± 0.00064 at the boc, βeff value is higher than β value of u-235, whilst at the eoc, βeff value is only slightly lower than 650 pcm. the values are expected as pu-239 is forming in both zones, reducing delayed neutron fraction. during the subsequent cycles, βeff should be decreased even more. reduced βeff, as previously mentioned, usually necessitates the reactivity control to be stricter. in this case, however, reactivity control can somehow be compensated by pu-239 addition into the core zone. this is due to pu-239 is significantly better than u-235 in the fast spectrum, so that criticality can be maintained even longer with lower excess reactivity. it must be understood that the βeff calculated in this study ignores the βeff fraction lost due to fuel circulation. calculating lost βeff must consider the fuel flow rate, which is beyond the scope of this study. fuel circulating time in the primary loop is usually less than a minute, thus some groups of delayed neutrons can also be generated when the fuel is returned into the core. therefore, even though the keff value of 13.7wt% enrichment is below βeff, as mentioned in the previous subsection, the real βeff may not necessarily above the keff. this will be addressed in future works. temperature coefficient of reactivity (tcr) is defined as reactivity change due to temperature change of core component. in any reactor, tcr must be kept negative. whilst thermal msr somehow suffers from the positive temperature feedback from graphite moderators, fast msr does not incur the same issue. in thermal reactors, tcr usually comprises of fuel coefficient of temperature (fct) and moderator coefficient of temperature (mct). since fast reactor omits moderator from the system, tcr in mcfr only considers fct. the latter consists of the fuel density coefficient and doppler coefficient. temperature simulated in this study is 600k, 900k and 1200k. molten salt expands when heated, lowering its density. thus, fuel density is corrected for a given temperature. fuel density correction is applied for both core zone and radial blanket zone. meanwhile, fuel density outside core zone and axial blanket zone are kept constant. the rationale is that fuel expansion due to heating occurs mainly in core zone and adjacent blanket zone. the temperature of non-fuel materials is adjusted accordingly. as a comparison, the calculation was also performed for fuel density adjustment in core zone only. using the above assumptions, tcr value of mcfr at boc is indicated in figure 3. 16 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 figure 3. tcr of mcfr at boc for density adjustment in core and radial blanket, tcr is calculated at -19.8 pcm/k, whilst when density adjustment in core only resulted in tcr of -21 pcm/k. a difference of 1.2 pcm/k is shown when fuel density in blanket zone is considered, which is insignificant compared to the absolute tcr value. nevertheless, it was seen that blanket expansion resulted in lower negative reactivity. this is due to lower neutron capture by the blanket, as depleted uranium is pushed out of the radial blanket zone when the fuel expands. either value is comparably more negative compared to other fast msr designs, including chinese mcfr. when compared to fluoride msfr, more negative tcr is induced by higher thermal expansion of chloride salt. thus, given the same temperature increase, chloride fuel expands larger than its fluoride counterpart, and thereby its fuel density is reduced even larger. meanwhile, compared to chinese mcfr, more negative tcr may be induced by different fuel cycles (u-pu for mcfr and u-th for chinese mcfr) or different core size. mcfr core diameter and height in this study are only half of that chinese mcfr dimension. the smaller core size of mcfr makes it more sensitive to fuel density change since more fissile will be pushed out of the core, further exacerbated by the high thermal expansion of chloride salt. the mcfr design satisfies inherent safety criteria. however, the extremely negative tcr necessitates more assessment of its reactivity control. in msr, the salt density coefficient can be treated as vcr. whilst thermal msr may incur a positive void coefficient if the core is under-moderated, fast msr does not face the same issue. in mcfr, vcr is calculated by reducing fuel density both in core zone and blanket zone. the assumption is similar with tcr, fuel density is corrected only in core zone and radial blanket zone, with other calculation with density correction in core zone only is performed as a comparison. keff change against void fraction is shown in figure 4. 17 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 figure 4. vcr of mcfr at boc with different salt density correction in both calculations, criticality change against the void is not linear. reactivity decreased the steepest from a void fraction 10% to 20%. however, from the void fraction of 40% to 50%, reactivity only decreased for less than 5 pcm for density reduction in core only. strangely, for density reduction in core and radial blanket, at the same void increase, the keff is increasing instead of decreasing. the average vcr is calculated at -176.59 pcm/void% for density reduction in core zone and 154.31 pcm/void% for density reduction in core zone + radial blanket zone. from those values, blanket salt expansion is proven to be lowering the negative reactivity, since density reduction means that lower fertile salt capture neutrons. thus, blanket salt expansion induced positive void reactivity, although not particularly significant compared to core salt expansion. both values are extremely negative and ensure that inherent safety is achieved. although, compared to msfr design, the difference in vcr value is significant. thermal expansion of chloride salt might play a part in this difference. to provide a better perspective, vcr for each step of void fraction change is given in table 3. table 3. vcr at each step of void change salt density correction core only core + radial blanket void change vcr for given void change (pcm) vcr for given void change (pcm) 0-10% -257.89 -260.39 10-20% -310.34 -265.30 20-30% -238.66 -206.79 30-40% -71.25 -56.43 40-50% -4.80 17.35 average -176.59 -154.31 18 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 conclusions an analysis of neutronic performance and safety on an mcfr showed encouraging results. for a fast reactor started with leu, achieving cr value at 0.9298 is remarkable. especially considering that mcfr ignores gaseous fission product removal and online fuel reprocessing altogether. for the next cycle, external fissile addition is unnecessary as critical mass is reduced and lower excess reactivity is required. mcfr design employed in this study fulfills inherent safety criteria. both tcr and vcr are sufficiently negative, although their highly negative value must be taken into consideration for reactivity control. βeff lowering after a year may reduce reactor controllability and must be considered for its reactivity control system since fuel makeup in mcfr is annually instead of daily. acknowledgements the work presented in this paper was supported by the research budget of the centre for nuclear reactor technology and safety, national nuclear energy agency, the fiscal year 2020. references [1] d. leblanc, 2010, molten salt reactors: a new beginning for an old idea, nucl. eng. des., volume 240, no. 6, page 1644–1656. 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[7] c. y. zou, c. z. cai, c. g. yu, j. h. wu, and j. g. chen, 2018, transition to thorium fuel cycle for tmsr, nucl. eng. des., volume 330, page 420–428. [8] j. devanney, l. jorgensen, j. livingston, r. w. moir, a. c. rodenburg and c. uhlik, 2015, thorcon executive summary. [9] h. g. macpherson, 1985, molten salt reactor adventure, nucl. sci. eng., volume 90, no. 4, page 374–380. [10] a. waris, i. k. aji, s. pramuditya, novitrian, s. permana, and z. su’ud, 2015, comparative studies on plutonium and minor actinides utilization in small molten salt reactors with various powers and core sizes, energy procedia, volume 71, page 62–68. 19 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 [11] d. heuer, e. merle-lucotte, m. allibert, m. brovchenko, v. ghetta, and p. rubiolo, 2014, towards the thorium fuel cycle with molten salt fast reactors, ann. nucl. energy, volume 64, page 421–429. [12] j. zhou, j. chen, j. wu, s. xia, and c. zou, 2020, influence of 7li enrichment on th-u fuel breeding performance for molten salt reactors under different neutron spectra, prog. nucl. energy, volume 120, page 103213. 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[online]. available: http://www.elysiumindustries.com/technology. [accessed: 08-apr-2020]. [19] j. smith and w. e. simmons, 1974, an assessment of a 2500 mwe molten chloride salt fast reactor, technical report, dorset, united kingdom atomic energy authority. [20] j. ligou, 1972, molten chlorides fast breeder reactor: reactor physics calculations, wuerenlingen, eidg. institut fuer reaktorforschung wuerenlingen. [21] a. mourogov and p. m. bokov, 2006, potentialities of the fast spectrum molten salt reactor concept: rebus-3700, energy convers. manag., volume 47, no. 17, page 2761–2771. [22] i. r. scott, 2019, the stable salt reactor—a radically simpler option for use of molten salt fuel, in thorium—energy for the future, springer singapore, page 445–453. [23] l.-y. he, g.-c. li, s.-p. xia, j.-g. chen, y. zou, and g.-m. liu, 2020, effect of 37cl enrichment on neutrons in a molten chloride salt fast reactor, nucl. sci. tech., volume 31, no. 3, page 27. [24] g. c. li et al., 2018, optimization of th-u fuel breeding based on a single-fluid doublezone thorium molten salt reactor, prog. nucl. energy, volume 108, page 144–151. [25] t. m. sembiring, j. susilo, and s. pinem, 2018, evaluation of the ap1000 delayed neutron parameters using mcnp6, in journal of physics: conference series, volume 962, page 012030. [26] m. aufiero et al., 2014, calculating the effective delayed neutron fraction in the molten salt fast reactor: analytical, deterministic and monte carlo approaches, ann. nucl. energy, volume 65, page 78–90. 20 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 8-20 eissn : 2747-173x submitted : march 20, 2021 accepted : april 28, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24962 [27] v. singh, m. r. lish, o. chvála, and b. r. upadhyaya, 2017, dynamics and control of molten-salt breeder reactor, nucl. eng. technol., volume 49, no. 5, page 887–895. [28] r. yoshioka and m. kinoshita, 2017, liquid fuel, thermal neutron spectrum reactors, in molten salt reactors and thorium energy, elsevier ltd, page 281–373. 44 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 identification of the geothermal heat at mount iyang-argopuro based on a data image of landsat 8 satellite and a data gravity of ggmplus satellite ega abi bahtiar 1,a , agus suprianto 1 and supriyadi 1 1 departement of physics, faculty of mathematics and natural sciences, universitas jember, kalimantan street no. 37, jember 68121, indonesia a egaabibahtiar@gmail.com abstract. in indonesia is the iyang-argopuro volcano complex. the research uses remote sensing methods and gravity methods conducted to study thermal anomalies and subsurface structures using data images of landsat 8 satellite and a data gravity of ggmplus satellite. moreover, the study aims to estimate the number of hoisting manifestations of the earth's heat at the compound of the iyang-argopuro volcano. landsat 8 satellite image data is a spectral band (band 1-9) and a thermal band (band 10 and 11). the data was done in radiometric corrections, radiance correction, and reflex corrections, and was thus obtained a value of ground surface temperature (lst). the data was done in radiometric corrections, radiance correction, and reflectance corrections, to get an lst value. processing data gravity of ggmplus satellites were with a bouguer correction, terrain corrections up to get a complete bouguer anomaly (abl) value. furthermore, the abl value consisting of regional and local anomalies is separated using an upward continuation filter to obtain local anomaly values. the results obtained from this study are five points of geothermal manifestation locations in the iyang-argopuro volcano complex which are located in the northern, central, southern and eastern parts. manifestations in the northern, central, and northeastern parts have ground surface temperatures of 24-31 ˚c. while manifestations in the central and eastern parts have a surface temperature of land 21-31 ˚c. the high ground temperature values at the five locations were associated with low gravity values ranging from -20 mgal to -10 mgal. the low gravity value is assumed to have a rock structure with a low-density value. low-density rock structures have the possibility of an outflow zone causing the soil surface temperature to be relatively high. keywords: geothermal, gravity anomaly, thermal anomaly, outflow zone introduction indonesia's geographical location is crossed by the pacific's ring of fire. this causes indonesia have to abundant natural resources, one of which is geothermal. geothermal potential in indonesia is quite large, around 40% of the total potential in the world. until 2014, the utilization of geothermal potential in indonesia has only reached 1341 mw or less than 5% of the available potential [1]. east java province has 13 geothermal potential points and one of them is located on mount iyang-argopuro. the potential contained in mount iyang-argopuro is 295 mw [2,3]. mount argopuro is one of the ancient volcanoes located on the island of java. mount iyangargopuro is an active volcano type b, which means that the volcanic activity of this mountain has decreased and is even categorized as resting [4]. the characteristic morphology of the mount iyang-argopuro area is surrounded by volcanic hills and the distribution of maar lakes. lake maar is a volcanic crater file in the past that is currently in the form of a basin filled with water, as well as sedimentary materials resulting from volcanic eruptions. the majority of the 45 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 lithology types of the mount iyang-argopuro geothermal area are pyroclastic rocks, basaltic andesite lava, and tuff [5]. research conducted by wulandari et al. stated that the mount iyang-argopuro geothermal system consists of a caprock layer, a reservoir rock layer, and a heat source rock layer. cover rock is in the shallowest layer below the soil surface. the reservoir rock layer is at a depth of 1000-3000 m below the ground surface. the heat source rock layer is a heat-producing rock located at a depth of 3000 m below the ground surface [5]. the structures that control the geothermal potential of mount iyang-argopuro include crater and fault structures. regionally, mount iyang-argopuro is included in the east java tectonic system with a diagonal shape with a northwest-southeast and northeast-southwest direction [6]. this fault structure on mount iyangargopuro allows geothermal manifestations to appear on the ground surface. geothermal manifestations that are often seen on the surface are hot springs, hot mud puddles, geysers, fumaroles, warm ground, alteration rocks, and other geothermal manifestations [7]. geothermal manifestations on mount iyang-argopuro are scattered at several points, one of which is the manifestation of hot springs on the northern slopes of mount argopuro in the area of rabunan, probolinggo. the manifestation of the hot springs arises because there is an outflow zone in the rabunan area. other manifestations also found weakly altered andesite outcrops with a whitish color in kali putih, cisentor. strong alteration zone on mount rengganis around the solfatara holes of mount rengganis [8]. manifestations of hot springs are also found on the western slopes located in the tiris area. the surface temperature of the area was recorded at 46-48 ˚c with a ph = 6. the existence of this geothermal manifestation is usually connected with the distribution of thermal temperatures that are higher than the temperature of the surrounding environment. the distribution of this temperature anomaly can be observed, one of which is remote sensing technology. theoretical background remote sensing is a technology to obtain information about an object, area, or phenomenon through the analysis of data obtained from a device without directly touching the object, area, or phenomenon [9]. remote sensing techniques are ideal for use in the initial investigation of geothermal potential. the results of remote sensing data processing can then interpret the earth's surface conditions and the distribution of soil temperature which can be used to identify potential geothermal locations [10,11]. one of the remote sensing data used for geothermal identification is landsat 8. landsat 8 has a special advantage compared to the previous generation landsat, namely more composite rgb constituent bands. in addition, landsat 8 has bands that make the color of objects more varied, namely 1-9, 10, and 11. the following table 1 is a characteristic of the landsat 8 satellite band. table 1. landsat 8 satellite sensor characteristics band λ(nm) resolusi (m) band 1–coastal aerosol 0.43-0.451 30 band 2-blue 0.45-0.51 30 band 3-green 0.53-0.59 30 46 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 band λ(nm) resolusi (m) band 4-red 0.64-0.67 30 band 5-near infrared (nir) 0.85-0.88 30 band 6-swir 1 1.57-1.65 30 band 7-swir 2 2.11-2.29 30 band 8-panchromatic 0.50-0.68 15 band 9-cirrus 1.36-1.38 30 band 10-thermal infrared (tirs) 1 10.60-11.19 100 band 11-thermal infrared (tirs) 2 11.50-12.51 100 bands 10 and 11 are thermal bands that are used to record thermal activity on the earth's surface, so they are very closely related to monitoring volcanic activity [12]. bands 1-9 are spectral bands that can be used to calculate the value of the vegetation index on the earth's surface [13]. normalized difference vegetation index (ndvi) is one of the algorithms used to determine vegetation values by involving satellite imagery [13]. ndvi is generally used to determine the level of vegetation density based on the difference between the maximum absorption in the red wave and the maximum reflectance in the near-infrared wave based on the leaf cell structure [14]. equation 1 below can be used to calculate the ndvi value. (1) = the near-infrared band reflectance value = the red band reflectance value image data processing using the ndvi algorithm will produce a new image with an ndvi value ranging from negative 1 to positive 1. a positive ndvi value indicates an object is a vegetation, while a negative ndvi value indicates a non-vegetated object. according to the departemen kehutanan (2012), the classification of vegetation density based on the ndvi value consists of five classes, namely unvegetated land, very high green, low green, medium green, and high green [15]. the classification of vegetation density can be seen in table 2. table 2. vegetation density class [15] class ndvi range value density level 1 -1 < ndvi ≤ -0.03 non-vegetated land 2 -0.03 < ndvi ≤ 0.15 very low green 3 0.15 < ndvi ≤ 0.25 low green 4 0.25 < ndvi ≤ 0.35 medium green 5 0.35 < ndvi ≤ 1 high greeni according to sutanto, the landsat 8 satellite has the best geodetic and geometric accuracy [16]. characteristics landsat 8 has a shorter band interval when compared to the previous generation landsat. landsat 8 has thermal infrared sensors (tirs) in bands 10 and 11 which have special characteristics used to record thermal activity on the earth's surface. bands 10 and 11 are closely related to the monitoring of volcanic activity [12]. monitoring of volcanic activity can be interpreted from the value of the ground surface temperature. 47 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 ground surface temperature is one of the parameters of the energy balance on the earth's surface. based on wein's law of displacement, which states have an object will emit a different electromagnetic wavelength at each emitter temperature. determination of the temperature of a mass can be known from the measurement of the emission of electromagnetic waves. the electromagnetic wave emission will be captured by the sensor in the form of a digital value [17]. the temperature of the object can be known by a digital value conversion step which aims to eliminate the influence of the atmosphere on the absolute temperature. temperature conversion needs to be done because the actual object is on the ground while the sensor is in outer space. this conversion in remote sensing techniques is commonly called the top of atmosphere (toa) correction, which is stated in the following equation [18]. (2) = radiance value or reflectance value = the radiance band or spectral band multiplier constant used = the addition constant of the radian band or spectral band used = digital number the radiance value obtained will then be used to calculate the value of the soil surface temperature. calculation of the value of the soil surface temperature is obtained from the conversion of the radian value to the brightness temperature (bt). according to kustiyo and pramono (2005), the bt value can be obtained from the following equation. ( ) (3) = radiance value and = thermal conversion constant = brightness temperature value the bt value obtained is then used to calculate the soil surface temperature using the following equation [18]. ( ) (4) = ground surface temperature (˚c) = brightness temperature value (k) = radiance emission wavelength (m) = kecepatan cahaya (3×10 8 ms -1 ) = nilai emisivitas this research uses remote sensing techniques in the form of alleged manifestations based on composite band data and geomorphological data. several studies that have been conducted state that there is a relationship between the distribution of existing thermal anomalies and subsurface structures in geothermal areas [19,20]. therefore, it is very important to carry out further research on the subsurface structure of the area to strengthen the allegations of identified geothermal manifestations. 48 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 one of the geophysical methods that can be used to determine subsurface structures is the gravity method. the gravity method is a method of investigating the subsurface of the earth which is based on newton's law [21]. the basic principle of the gravity method is to measure the difference in the value of the gravitational field caused by an uneven rock mass. the difference in gravity values can be used to estimate the geometry of subsurface structures globally including their density and depth [22]. based on the gravitational force expressed in newton's law of attraction between two masses of particles m1 and m2, it is directly proportional to the product of their masses and inversely proportional to the square of the distance [21]. the following is an equation of newton's law that states the equation: ( ) (5) ( ) = gravity (n) = mass (kg) = distance (m) = gravity constant (6.6732 x 10 -11 nm 2 /kg 2 ) the following is figure 1 of the attractive force between 2 particles on a 2-dimensional plane: figure 1. the gravitational force of 2 particles on a 2-dimensional plane [21] the method of gravity is also based on newton's second law of the relationship between force and acceleration. newton's second law reads "the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass [21]. mathematically newton's second law can be expressed in the following equation: (6) (7) so that equations (2) and (4) can be combined into a gravitational force, which is expressed as follows: (8) = acceleration of the earth's gravitational force (m/s 2 ) = gravity (n) 49 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 = mass (kg) = obect mass (kg) = gravitational constant (6.6732 x 10 -11 nm 2 /kg 2 ) = distance between two objects (m) the gravity data used in this study is ggmplus gravity data. global gravity model plus (ggmplus) is satellite gravity data which is a combination of the grace, goce, egm 2008 satellites, and high-resolution topographic information from the srtm topography, which is approximately 200 m resolution. ggmplus gravity data provides a grid of data on gravitational acceleration, gravity disturbance, quasigeoid undulation, and north-south and west-east vertical deflections. the ggmplus gravity data used in this study is gravity disturbance data. gravity disturbance data is satellite gravity data which is equivalent to gravity data that has been corrected in free air. the gravity disturbance data needs to be corrected to eliminate the values that affect the gravity value. the corrections include topographic corrections consisting of bouguer corrections and terrain corrections. materials and methods this research begins with a topic. the topic of this research is the utilization of landsat 8 satellite imagery data and ggmplus satellite gravity data which are used as the first step in geothermal research at the iyang-argopuro volcano complex. the type of data used in this study is secondary quantitative data in the form of landsat 8 satellite image data downloaded from the website https://earthexplorer.usgs.gov/, gravity data from ggmplus downloaded from the website http://ddfe.curtin.edu.au/gravitymodels/ggmplus/data/ and the srtm dem data downloaded from the website http://srtm.csi.cgiar.org/srtmdata. the research area is the mount iyang-argopuro complex with the research coordinates of 7.895-8.045˚ south latitude and 113.511-113.705˚ east longitude. the data obtained were then corrected based on each method. 50 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 figure 2. stage of remote sensing methods the data of landsat 8 satellite imagery is a radiometric correction to eliminate the influence of the atmosphere during image recording. radiometric correction or top of atmosphere (toa) consists of two kinds of corrections, namely the toa reflectance correction (reflectance bands (4 and 5)) and toa radiance correction (radiance bands (10 and 11)). the result of the reflectance toa correction is the reflectance value and the result of the radiance toa correction is the radiance value. the reflectance value obtained is then used for filtering to obtain the ndvi value. the ndvi value is obtained from equation 1. furthermore, the ndvi value obtained is used to calculate the vegetation proportion (vp) value with the following equation. ( ) (9) the pv value is then used to determine the soil surface emissivity (lse) value. the lse value is used to reduce errors in calculating the soil surface temperature value. the emissivity value is obtained from the following equation. data collection toa radiance toa reflectance thermal band (10 dan 11) spectral band (4 dan 5) landsat 8 satellite image data filtering brightness temperature (bt) normal difference vegetasi index (ndvi) land surface thermal (lst) land surface emissivity (lse) surface temperature distribution map 51 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 (10) furthermore, the radian value obtained from the toa radian correction is used to calculate the value of the soil surface temperature. the radian value is then converted to brightness temperature (bt) with equation 3. furthermore, the bt value is used to calculate the value of the soil surface temperature with equation 4. after the soil surface temperature value is obtained, it will then be interpreted in the form of a map of the ground surface temperature. the ground surface temperature map will be used as a reference in determining geothermal manifestations, but the data is still not strong, so it will also be seen from the subsurface structure by looking at the local gravity value of the area. figure 3. stage of gravity method ggmplus satellite gravity data (gravity disturbance) is equivalent to gravity data corrected in free air. so only need to do bouguer correction and terrain correction to get the complete bouguer anomaly (cba) value. bouguer correction is carried out with the following equation [23]. (11) = bouguer correction g = gravity constant= 6.67 x 10 -11 m 3 kg -1 s -2 ρ = rock density (2.67 gr/cm 3 ) h = the height of the point is a measurement of gravity (from dem srtm data) the results of the bouguer correction are then used to find the value of the simple bouguer anomaly (sba) with the following equation. (12) data collection gravity ggm plus data (gravidistubance) bouguer correction simple bouguer anomaly (sba) terrain correction complete bouguer anomaly(cba) data topography (dem srtm) upward continuation local anomaly data 52 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 where dg is the gravity disturbance value and kb is the bouguer correction value. the abs value is still influenced by the topography at the measurement point. so it is necessary to do terrain correction to eliminate the influence of the topography. according to reynolds (2011), the terrain correction is formulated by the following equation [24]. ( * √ √ +) (13) n = number of compartments in the research zone r2 = outer radius (m) r1 = inner radius (m) z = the difference between the average height of the compartment and the measuring point (m) (from dem srtm data) terrain correction is carried out with the help of oasis montaj 6.4.2 software. the results of the subsequent terrain correction are used to find the abl value with the following equation. (14) the abl value that has been obtained is then carried out with upward continuation filtering to separate local anomalies from regional anomalies in the area. the local anomaly data will be used to interpret the structure of the shallow surface area of the area. results and discussion landsat 8 satellite imagery data that has been processed will produce vegetation density values and soil surface temperature values. the vegetation density values obtained are then classified into five classes, as shown in table 2. the results of the classification are then used as a vegetation density map as shown in figure 4 below. 53 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 figure 4. vegetation density map of the iyang-argopuro volcano complex figure 4 shows that the iyang-argopuro volcano complex is dominated by a high green vegetation density class which is indicated by a dark green color. the middle part of the iyang argopuro volcano complex has a low greenish vegetation density class. there is an unvegetated area marked by a black circle, the area is a living garden lake. taman hidup lake is located at coordinates -7.978176 south latitude, 113.532658 east longitude, which is located in krucil district, probolinggo regency. based on the information on vegetation density in figure 4, the location of the non-vegetated land area of taman hidup lake has matches with the location coordinates with information from google earth. the vegetation density value in figure 4 will be used as a reference in mapping geothermal manifestations in the iyang-argopuro volcano complex. according to pietersz et. al. (2018) areas that have a high greenish vegetation density class generally have a lower ground surface temperature than the surrounding area [25]. however, this does not always apply to areas that have geothermal potential. the soil surface temperature in the geothermal potential area will be high even though the area has a high vegetation density class. the ndvi value obtained from processing band 4 and band 5 data in figure 4 is then used as input to find the vegetation proportion (pv) value. the pv value obtained is used to determine the estimated land surface (lse) value. furthermore, the lse value serves to reduce errors in calculating the soil surface temperature value. the soil surface temperature values in the iyang-argopuro volcano complex range from 12 ˚c to 31 ˚c, as shown in figure 5 below. 54 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 figure 5. map of ground surface temperature of iyang argopuro volcano complex figure 5 shows that the iyang-argopuro volcano complex has a high ground surface temperature ranging from 22-31 ˚c which is indicated by orange and red colors. areas suspected to be geothermal manifestations are marked with red circles. areas with high surface temperatures in the eastern part are not suspected as geothermal manifestations because based on figure 4 these areas have low vegetation density values. in conducting the initial estimation of geothermal manifestations in the iyang-argopuro volcano complex using the value of the ground surface temperature, it will be compared with the reference ground surface temperature. according to research conducted by purwantara (2015), the mount iyang-argopuro complex has the highest ground surface temperature ranging from 22.1 ˚c [26]. so that the ground surface temperature in figure 5 with a range of values above 22.1 ˚c can be assumed as a geothermal manifestation. furthermore, the alleged manifestation of the soil surface temperature value will be strengthened by looking at the subsurface structure in the study area. the subsurface structure can be identified by looking at the value of local gravity in the study area. the gravity disturbance data for ggmplus is equivalent to gravity data corrected by free air, so to get the abl value, only bouguer correction and terrain correction are needed. abl data is gravitational field data that is influenced by variations in rock density below the surface. this abl data can interpret the subsurface structure of the study area. the abl contour map in the iyang-argopuro volcano complex has a range of values between 32 mgal to 90 mgal. as shown by figure 6 below. 55 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 figure 6. abl contour map of the iyang-argopuro volcano complex the abl value in the center of the iyang-argopuro volcano complex ranges from 33 mgal to 42 mgal which is indicated by the purple color. in the east, it is shown by a blue-purple color with a range of 20 mgal to 52 mgal. the areas indicated by purple in the central and eastern parts are thought to be related to geothermal manifestations. in this study, the abl value was used to determine the subsurface geological structure. determination of the subsurface structure requires local anomaly data obtained from the separation of abl values into local anomalies and regional anomalies. separation of these anomalies is done by using the upward continuation filtering method using the magpick software. local anomaly data obtained can interpret the shallow subsurface structure in the study area. the best upward continuation filtering results at an upward value of 6000 m. the following figure 7 is a map of local anomalies in the iyang-argopuro volcano complex which has a value range of -20 mgal to 28 mgal. 56 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 figure 7. local anomaly map as a result of continuation above 6000 m low local anomalies are indicated by purple and blue colors which have a value of 0 mgal to 20 mgal. the moderate anomaly has a value range of 0 mgal to 14 mgal which is indicated by green and yellow colors. while the high anomaly values are indicated by the orange and red colors which have a value range of 14 mgal to 28 mgal. local anomaly values which are suspected as geothermal manifestations are located in the central, eastern, southern, and northern parts indicated by purple and blue colors. the low local anomaly which is suspected as a geothermal manifestation in figure 7 will be searched for its relationship with the soil surface temperature in the study area. figure 8 below is a map of overlay results from ground surface temperature data with local anomalies in the study area. 57 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 figure 8. overlay map of geothermal manifestations with administrative information of the research area figure 8 shows that there are five locations of geothermal manifestations in the iyang-argopuro volcano complex. the location of these manifestations has a ground surface temperature of 20 c to 31 ˚c (yellow, orange, and red lines) with low gravity values ranging from -20 mgal to -6 mgal (purple color). the location of the first geothermal manifestation is located in the center with a temperature of 24-31 ˚c and gravity values ranging from -20 mgal to -10 mgal. the location of the second manifestation is in the northeast with a temperature of 22-31 ˚c and gravity values ranging from -12 mgal to -8 mgal. the location of the third manifestation is in the northern part with a temperature of 24-31 ˚c and a gravity value of -16 mgal to -10 mgal. the location of the fourth manifestation is in the eastern part with a temperature of 24 -31 ˚c and a gravity value of -8 mgal to -6 mgal. the fifth manifestation location is in the southern part with a temperature of 22-31 ˚c and gravity values ranging from -12 mgal to -6 mgal rock structures with low density. this condition allows the outflow zone in the area. the outflow zone allows hot fluids in the earth to appear on the ground surface in the form of geothermal manifestations, one of which is a relatively high ground surface temperature from the surrounding area. the allegation of geothermal manifestations in the iyang-argopuro volcano complex in figure 8 is getting stronger. this occurs because the thermal anomaly obtained from processing landsat 8 satellite imagery is related to the local anomaly obtained from processing the ggmplus gravity data as shown in figure 8. 58 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 1, page 44-59 eissn : 2747-173x submitted : april 1, 2021 accepted : may 10, 2021 online : may 28, 2021 doi : 10.19184/cerimre.v4i1.24966 conclusions this study has five points of geothermal manifestation locations in the iyang-argopuro volcano complex which are located in the northern, central, southern and eastern parts. manifestations in the northern, central, and northeastern parts have ground surface temperatures of 24 -31 ˚c. while manifestations in the central and eastern parts have a surface temperature of land 21-31 ˚c. the location of the high ground surface temperature is associated with low gravity values with values ranging from -20 mgal to -6 mgal. the location point is thought to be a geothermal manifestation in the iyang-argopuro volcano complex. the location of the geothermal manifestation is located in the middle of the peaks of mount rengganis and mount argopuro. the northern part is in the rabunan area, probolinggo. the northeastern part of the cikasur area, situbondo. the eastern part is in the bondowoso regency area and the southern part is in bangsalsari, jember. references [1] kasbani, 2014, statistik energi terbarukan, direktorat jenderal energi baru terbarukan, dan konservasi energi, kementerian energi dan sumber daya mineral (kesdm). 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[22] b. a. sadjab, 2017, identifikasi struktur bawah permukaan berdasarkan analisis anomali gravitasi dan didukung oleh data focal mechanism provinsi nusa tenggara timur lembar kupang-atambua, universitas gadjah mada. [23] m. sarkowi, 2010, identifikasi struktur daerah panasbumi ulubelu berdasarkan analisa data svd anomali bouguer, sains mipa 16 (2): page 111–118. [24] j. m. reynolds, 2011, an introduction to applied and environmental geophysics, john wiley & sons. [25] j. h. pietersz, j. matinahoru, and r. loppies, 2018, pendekatan indeks vegetasi untuk mengevaluasi kenyamanan termal menggunakan data satelit landsat-tm di kota ambon, agrologia 4 (2). [26] s. purwantara, 2015, studi temperatur udara terkini di wilayah di jawa tengah dan diy, geomedia: majalah ilmiah dan informasi kegeografian 13 (1). 19 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 young’s modulus calculation of some metals using molecular dynamics method based on the morse potential fitriana faizatu zahroh 1.a , iwan sugihartono 2 and ernik d. safitri 1 1 department of physics. faculty of mathematics and natural sciences, university of jember, jl. kalimantan no. 37, jember 68121, indonesia 2 department of physics, faculty of mathematics and natural sciences, universitas negeri jakarta, jl. r.mangun muka raya, rt.11/rw.14, rawamangun, kec. pulo gadung, kota jakarta timur, daerah khusus ibukota jakarta 13220, indonesia a fitrianazahrah@gmail.com abstract. it has been investigated computationally young's modulus of some metals: nickel, copper, silver, gold, and aluminum. the offset method can graphically determine young's modulus property by determining the elastic region based on the straight line intersection formed at a 0.2% strain against the stress-strain curve. in this simulation work, young’s modulus calculation was performed by using the lammps molecular dynamics software. the interatomic potential used to represent the interactions among atoms of materials in this simulation is the morse potential. the metals under-investigated in this work are nickel, copper, silver, gold, and aluminum, and we got the results are 209.2 gpa, 110.8 gpa, 83.8 gpa, 79.2 gpa, and 70.3 gpa, respectively. the young's modulus of the materials was also computed as temperature variations from 300k to the melting point to determine the effect of temperature on young's modulus, and it is tensile strength. from our work we can found that the higher the temperature, the lower young's modulus value. in addition, it can be seen that nickel metal has good temperature resistance. this is evidenced by the change in the nickel-metal phase near its melting point. keywords: molecular dynamics, morse potential, young’s modulus, stress-strain introduction the development of new/novel materials utilizing computational and simulation methods is one of the creative ways to optimize and streamline material research before direct experimental synthesis. material research by reviewing the microscopic structure of materials can be used to predict materials macroscopically. by modeling and simulating materials in micro sizes, the macro-physical properties of materials can be estimated using young’s modulus of copper, silver, gold, aluminum, and nickel metals. the elasticity property is the tendency of solid material to return to its original shape before permanently deformed [1]. deformation in a solid material occurs when a force is applied to it. a measure of the degree of elasticity of a material indicates the material's resistance to elastic deformation due to external forces known as young's modulus [2]. investigation of young's modulus of metallic materials has ever also been previously carried out by camprubi [3] for nano-sized copper wire material. ferguson [4] also studied the young modulus of pure aluminum metal-based on eam potential. 20 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 even many studies developed the eam potential for metals. in our work, the calculation of young's modulus is carried out using the molecular dynamics method based on metals' morse potential. the fitting process is carried out to get proper morse potential parameters based on available experimental data (at 300k) before further evaluation to determine young's modulus's temperature dependence. the use of morse potential will simplify our simulation as a preliminary study of metals. we use the lammps molecular dynamics code for simulating the phenomena (lammps.sandia.gov). materials and methods 1. young’s modulus the young’s modulus of the material is closely related to material characteristics based on the degree of stiffness when external forces influence it. materials with large young's modulus are relatively non-elongated so that tremendous stress is required to produce deformation [5]. young's modulus of material can be determined from a macroscopic perspective by knowing the ratio of stress to strain, known as hooke's law. (1) where: e = young’s modulus (gpa) σ = stress (gpa) ɛ = strain f = tensile force on metal (ev/å) a = surface area of metal (å 2 ) = length of metal before being subjected to a load (å) = length of metal after being subjected to a load (å) = change in length of metal before and after being subjected to a load (å) calculation of young's modulus of pure metal is determined using the offset method by calculating the stress's slope to the elastic region's strain curve, namely the strain 0.002 [9]. the limit of the elasticity of the material is known as the yield stress (yield). the slope area's determination starts from zero to the yield point, that is, when the stress-to-strain curve is no longer linear. the young (e) modulus values of some metals are represented by young's modulus (y), according to table 1 below. table 1. young's modulus values of some pure metals material young’s modulus (pa) references aluminum 7.0 x 10 10 [5] brass 9.0 x 10 10 copper 11.0 x 10 10 kerona glass 6.0 x 10 10 lead 1.6 x 10 10 nickel 21.0 x 10 10 21 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 material young’s modulus (pa) references steel 20.0 x 10 10 gold 7.9 x 10 10 [6] silver 8.25 x 10 10 [4] experimentally, the study of the effect of temperature on young's modulus can be carried out using a tuning fork made of pure aluminum metal as the material [7]. based on this research, it can be seen that the increase in material temperature affects young's modulus value. the higher the temperature of the material, the lower young's modulus value. the load applied to the material continuously will cause the stress and strain relationship to be non-linear. this area is called the plastic area, where the material cannot return to its original state when the applied load is removed. after passing the material's yield point, the stress will continue to increase for a specific limit called maximum stress. in this condition, the material can accept. the maximum stress is usually referred to as the tensile strength or uts (ultimate tensile strength) [8]. after passing through the tensile strength, the material's ability to accept loads will decrease until the material breaks (fracture). 2. metals each metal has different characteristics so that several tests can be carried out, for example, tensile testing, impact tests, and hardness tests to determine the properties of the metal, especially its mechanical properties [9]. the following are some explanations of the metal materials used. a) copper copper is a metal that has an fcc crystal structure with a lattice constant of 3.6062 å [10] and a melting point of 1358 k [11], which is often applied as nanowires. copper has young's modulus of 110 gpa [5] and is often used in uranium alloy compositions as an aircraft component. b) silver silver is a metal with a relative mass of 107.87 grams/mol, composed of an fcc crystal structure with a lattice constant of 4.0729 å [10]. based on its mechanical properties, silver has a lower young's modulus value than copper and nickel, namely 82.5 gpa at 293 k [4]. c) gold gold is an ideal metallic material for wires and electrodes at the nanoscale [12]. at the size of nanoparticles, gold and silver metals have been widely used as sensors, catalysis, biochemistry, optics, and electronics [13]. gold is composed of an fcc crystal structure with a lattice constant of 4.0588 å [14] and has a melting point of 1338 k [11]. d) aluminum aluminum is a light metal with an atomic mass of 26.981 grams/mol and has resistance to corrosion [15]. the metal comprises an fcc crystal structure with a lattice constant of 4.0305 å [10], young & freedman [5] stated in their book that aluminum metal has young's modulus value of 70 gpa. aluminum will undergo a phase change to become liquid at a temperature of 933.5 k [11]. 22 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 e) nickel nickel is a metal that has an fcc crystal structure with a lattice constant of 3.5214 å [10] and is often used in industry as a building block for steel. one of the advantages of nickel is that it has corrosion resistance properties. however, in a pure state, it is soft so that when combined with several other metals such as chrome and iron, it will be the right choice to form hardened corrosion-resistant steels. the metal has a relative mass of 58.71 grams/mol [16]. nickel is very easy to combine with other metal elements, so its use is essential as a constituent of metal alloys for corrosion and heat resistance considering its high melting point is 1728 k [16]. 3. molecular dynamics methods molecular dynamics simulations predict the physical quantities of interactions at the atomic or molecular level based on the designed material model and based on the input simulation d ata given [17]. the research method used in this research is the classical molecular dynamics method, which can solve or find solutions to newton's equations of motion using a potential function by the results of the atomic trajectory solution, which in this study is based on morse's potential. based on this, there is a relationship between the macroscopic properties of matter and the interactions at the atomic or molecular level. 4. interactions among atoms at the microscopic scale, each atom that is close to each other will interact with each other due to the atoms' forces. so it requires an interaction force between atoms, which is equivalent to the interaction potential used. the selection of interaction potentials greatly determines the results of the simulation performed. rapaport [18] stated two main principles in the interaction between atoms: attractive forces and repulsive forces between atoms. first, if the atomic pairs are separated at a close distance, the resultant interaction forces will repel each other. second, if the atomic pairs are separated at a great distance, the resultant interaction forces will attract each other. however, at a certain distance, the interaction styles that occur will cancel each other out so that the resultant interaction force will be zero. there is a dependence between the attractive interactions and the repulsive interactions between atoms on the potential energy, according to figure 1 [5]. figure 1. the dependence between attractive interactions and repulsive interactions between atoms on potential energy the interaction potential between atoms consists of a position function representing the atoms' potential energy when located in a particular configuration. this can be described using the relative position of an atom to another atom, which can be explained by the equation: 23 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 u(r1.r2....) = v1 + v2 + v3 (2) the force that makes the atoms in an atomic system interact unbound when the atoms are close together or neighboring can survive in composing the crystal is the van der waals’s force [19]. 5. morse potential apart from the lennard jones potential and the eam (embedded atomic method), another potential is often used in molecular dynamics simulations, namely the morse potential. this potential has been widely used to explain the various properties of crystals. the characteristics of these crystals include cohesive energy, the lattice constant, compressibility, and elasticity constant. the usual morse potential function is written in the following equation: u(rij) = d{exp [-2α (rij-r0)] 2exp [α(rij-r0)]} (3) where, u(rij) = interaction energy between atoms i and j separated at a distance (ev) d = potential well depth and is the energy parameter (ev) α = potential width controlling parameter (å-1) r = distance between atoms (å) r0 =equilibrium distance between atoms i and j at minimum potential (å) the morse potential parameters of some pure cubic metals are composed of the fcc crystal structure, according to table 2. tabel 2. morse potential parameters are suitable for some pure metals metal lattice constant α (å -1 ) d (ev) r0 (å) cu 3.6062 2.369 0.1716 2.5904 ag 4.0729 2.389 0.1534 2.9060 au 4.0588 3.174 0.1588 2.8764 al 4.0305 2.335 0.1139 2.8798 ni 3.5214 2.544 0.2091 2.5218 pb 4.9356 -2.398 0.0849 3.5022 6. equation of motion in classical molecular dynamics, each atom and molecule is treated as a point mass that satisfies newton's motion equations. the simulation is based on classical mechanics for a system of n atoms interacting through a potential function. this equation of motion is known as newton's second law, namely: (4) is the net force in newtons on atom i, determined from the negative gradient of potential energy based on atomic coordinates. (5) 24 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 n is the number of atoms in the simulation [3]. information about the correlation between the microscopic and macroscopic states of the material can be explained using an ensemble. the system under review is simulated in an isobaric-isothermal ensemble. in this ensemble, the number of particles, pressure, and temperature as macroscopic properties of the system can be maintained at a constant value while the volume of the system changes. volume changes occur as a result of the load on the system. results and discussion the selection of the potential function and its parameters is essential for obtaining simulation result data suitable for the experiment. to get results consistent with experiments on macrosized materials, the system is conditioned to a pressure of 1 atm. the results obtained in this study are: 1. correction of morse potential parameters (d, α and r0) correction of the morse potential parameter in the pure metal system was carried out to determine young's modulus value at a temperature of 300k. the young modulus value data was obtained, which was by the experimental data. furthermore, these three parameters are used to determine young's modulus value with temperature variations leading to its melting point. these parameters are obtained by running the simulation based on the input given. based on the correction of the morse potential parameter that has been done. it is obtained that the parameter values d, α, and r0 are appropriate for the case under study. parameter d shows the potential well depth expressed in energy units (ev). the parameter α is a parameter controlling the potential width expressed in (å -1 ). meanwhile, r0 shows the equilibrium distance between atoms i and j when the minimum potential is expressed in units (å). parameters d, α, and r0 on the calculated young's modulus, along with the percentage of the discrepancy, are by table 3. tabel 3. morse potential parameter to young's modulus value of the pure metal material d (ev) α (å -1 ) r0 (å) e (gpa) discrepancy (%) cu 0.1716 2.538 2.5940 110.8 0.7 ag 0.1534 2.491 2.9060 83.8 1.6 au 0.1588 2.357 2.8767 79.2 0.2 al 0.1139 2.743 2.8798 70.3 0.4 ni 0.2110 3.080 2.5218 209.2 0.4 2. determination of young’s modulus value of pure metal at 300 k the calculation of young's modulus values for the five materials is carried out based on the deformation system obtained. the deformation system simulates the material's mechanical properties by using a tensile test on the x-coordinate vector so that the system changes shape and size. the deformation system consists of stress (σ) at coordinates (x, y, z) and strain (ε). the following is the stress-strain curve generated from the five materials deformation system at a temperature of 300k. according to figures 2,3,4,5 and 6. 25 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 figure 2. pure copper stress-strain curve at a temperature of 300k based on figure 2, it is shown that the limit of the elasticity area occurs at a stress of 4.9 gpa with a strain of 0.05. also, it can be seen that the tensile strength of the copper metal system is 11.4 gpa. which occurs at a strain of 0.13. figure 2 shows that the system experiences a sharp stress drop when it passes through the tensile strength region of up to 4.5 gpa, which occurs in the strain area between 0.14 to 0.16. this shows that in this area, the system has almost lost resistance to a given load. at a strain of 0.17 to 0.3, it can be seen that the system has a small load resistance, which is indicated by a stress value range of 2.5 to 3 gpa. figure 3. pure silver stress-strain curve at 300k based on figure 3, it is shown that the limit of the elasticity area occurs at a stress of 3.1 gpa with a strain of 0.04. in addition, it can be seen that the tensile strength of the copper metal system is 6.9 gpa, which occurs at a strain of 0.1. figure 3 shows that the system has experienced a sharp stress drop from the tensile strength area to 0.7 gpa, which occurs in the strain area between 0.11 to 0.12. however, at a strain of 0.13 to 0.3, it can be seen that the system goes into a state where the resistance to loading is zero. this indicates that the system has fractured. 26 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 figure 4. the stress-strain curve of pure gold at a temperature of 300k based on figure 4. it is shown that the limit of the elasticity area occurs at a stress of 3.4 gpa with a strain of 0.04. in addition, it can be seen that the tensile strength of the copper metal system is 7.1 gpa, which occurs at a strain of 0.1. figure 4.8 shows that the system has experienced a sharp stress drop from the tensile strength area to 0.8 gpa, which occurs in the strain area between 0.12 to 0.14. however, at a strain of 0.15 to 0.3, it can be seen that the system goes into a state where the resistance to loading is zero. as with silver material, it indicates that the system has fractured. figure 5. the stress-strain curve of pure aluminum at a temperature of 300 k based on figure 5, it is shown that the limit of the elasticity area occurs at a stress of 2.6 gpa with a strain of 0.04. in addition, it can be seen that the tensile strength of the copper metal system is 5.3 gpa, which occurs at a strain of 0.09. in figure 4.9. it can be seen that the system has experienced a sharp stress drop from the tensile strength region to 0.3 gpa, which occurs in the strain area between 0.1 to 0.11. however, at a strain of 0.11 to 0.3, it can be seen that the system goes into a state where the resistance to loading is zero. this shows that after a sharp drop in stress, the system fractures. 27 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 figure 6. the stress-strain curve of pure aluminum at a temperature of 300k based on figure 6, it is shown that the boundary of the elasticity area occurs at a stress of 8.3 gpa with a strain of 0.04. also, it can be seen that the tensile strength of the copper metal system is 18.9 gpa, which occurs in a strain of 0.12. figure 6 shows that the system experiences a sharp stress drop from its tensile strength area to 5.3 gpa, which occurs in the strain area between 0.12 to 0.14. however, at a strain of 0.15 to 0.3. it can be seen that the system has a small load resistance, with a stress value range of 4 to 5 gpa. based on figures 2,3,4,5 and 6, it can be concluded that the increase in the tensile strength of the material is proportional to the increase in the yield stress of each material. also, the copper and nickel metal systems do not fracture as in silver, gold, and aluminum at the end of the simulation. referring to the morse potential parameter in table 3, the young modulus value for each pure metal material at a temperature of 300k is obtained along with the value of the discrepancy , according to table 4. tabel 4. young's modulus value of the pure metal at a temperature of 300k material reference (gpa) stimulation (gpa) discrepancy (%) cu 110.0 110.8 0.7 ag 82.5 83.8 1.6 au 79.0 79.2 0.2 al 70.0 70.3 0.4 ni 210.0 209.2 0.4 based on the simulation results, the system's stress has a gpa scale, considering the material used is nano-sized metal, which has a regular arrangement of atoms. whereas for materials such as macro-sized metals and composites, the stress produced has an mpa scale, which is undoubtedly far from the simulation results. this is because the order of the atoms is not as good as the system in the simulation. based on table 4, it is known that the young gold modulus has a much better level of accuracy than other metals. the smaller discrepancy value of gold indicates this compared to other metals, namely 0.2%. the lowest level of accuracy occurs in silver metal, where the discrepancy value is 1.6%. however, each of the young modulus values above can be said to be following experimental data considering that the discrepancy value obtained is less than 2%. 28 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 the accuracy of young's modulus values for these five materials is highly dependent on the suitability of the morse potential parameters used. 3. young’s modulus at various temperature variations in addition to the temperature of 300k, the determination of the young modulus value of pure metal using molecular dynamics methods is also carried out based on temperature variations. the temperature used starts from 300k to close to the melting temperature. temperature variation is carried out in one direction, from the smallest to the largest value. this was done to determine the resistance of the material to loading during extreme temperatures. knowing young's modulus value shows how much stress the material can accept up to the elasticity limit of the material. for that, a stress-strain curve is needed for each temperature variation. figure 7 shows the stress-strain curve for pure copper metal with temperature variations. figure 7. the stress-strain curve in pure copper with temperature variations based on figure 7, it can be seen that the increase in temperature applied to copper metal causes a decrease in the value of its tensile strength. the more significant the decrease in tensile strength, the easier the material is deformed. the graph shows that copper metal undergoes a phase change to become liquid at a temperature of 1273k before reaching its melting point at 1358k. this is evidenced by the absence of a stress-strain curve pattern as at the previous temperature. at a temperature of 1273k, the calculation of young's modulus value cannot be carried out considering that the stress-strain curve is linear along the x-axis with a stress value of 0 gpa along with the strain. at an initial temperature, such as at a temperature of 300 k, it can be seen that there is a sharp drop in stress when the load continuously exceeds its tensile strength. this shows that the metal is almost losing its ability to defend itself from deformation due to the load received until, in the end, the metal experiences continuous elongation with relatively constant stress. however, when the metal temperature has approached its melting temperature, such as at 1223k, the stress gradually decreases. this indicates that at this temperature, copper metal has a low resistance to deformation. 29 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 in addition to copper metal, the resistance of the material to a given load with temperature variations in silver metal is shown in figure 8. figure 8. the stress-strain curve in pure silver with temperature variations the increase in temperature applied to silver metal causes a decrease in the value of its tensile strength, as in figure 8. the graph shows that silver metal undergoes a phase change to become liquid at a temperature of 873k, long before reaching its melting point, which is at 1235k. this is evidenced by the absence of a stress-strain curve pattern as at the previous temperature. at a temperature of 873k, the calculation of young's modulus value cannot be carried out considering that the stress-strain curve is linear along the x-axis with a stress value of 0 gpa along with the strain. figure 9. stress-strain curves on pure gold with temperature variations the increase in temperature applied to the gold metal also causes a decrease in the value of its tensile strength, as shown in figure 9. the graph shows that the gold metal undergoes a phase change to become liquid at a temperature of 873k, long before it reaches its melting point at 1338k. this is evidenced by the absence of a stress-strain curve pattern like at the previous temperature. at a temperature of 873k, the calculation of young's modulus value cannot be carried out considering that the stress-strain curve is linear along the x-axis with a stress value 30 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 of 0 gpa along with the strain. at a temperature of 823k, the voltage drops slowly. this indicates that at this temperature, gold metal has low resistance to deformation. figure 10. stress-strain curves on pure aluminum with temperature variations based on figure 10, it can be seen that the increase in temperature applied to aluminum metal also causes a decrease in the value of its tensile strength. the graph shows that aluminum metal undergoes a phase change to become liquid at a temperature of 723k before reaching its melting point (933.5k). at a temperature of 723 k, the calculation of young's modulus value cannot be carried out considering that the stress-strain curve is linear along the x-axis with a stress value of 0 gpa along with the strain. figure 11. the stress-strain curve in pure nickel with temperature variations based on figure 11, the metal's resistance to deformation at low temperatures, which is between 300k and 573k, is still quite good. this is evidenced by the metal's ability to maintain the strain that occurs at the point of its tensile strength, which is still quite good. on the other 31 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 hand, at temperatures of 1423k to 1673k, the metal is seen to experience a relatively more significant decrease in tensile strength than at the previous temperature. figure 11 shows that nickel-metal undergoes a phase change at a temperature of 1723k. young's modulus can be determined when the material is still in a solid phase. solid material has a tremendous inter-atomic binding energy compared to the liquid and gas phases. this is related to the orderly arrangement of atoms so that the bonds between atoms that occur are also stronger. in the liquid phase, the arrangement between atoms is more irregular. that is why it is difficult to determine the young modulus when it approaches its melting point. the relationship between the young modulus values of pure metals and their temperature variations is shown in figure 12. figure 12. the relationship between young’s modulus values of pure metals to temperature variations based on figure 12, it can be seen that each pure metal has decreased with the increase in temperature. microscopically, the liquid phase of the material has a greater distance between atoms than the solid phase. this causes the binding force between atoms in the liquid phase to be smaller than in the solid phase. visualization of the effect of temperature the temperature variations are given to each pure metal material affect the structure of the material. this is indicated by the percentage change in crystal structure at any given temperature variation. based on the simulation results that have been carried out. when given temperature variations under the effect of a given loading, the behavior of the material can be seen in the visualization display using the ovito software. based on this visualization, the system state of each material can be seen. the state of the system starts from a temperature of 300k, as in figure 13, to a state where the material undergoes a phase change to become liquid, as in figure 14. 32 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 (a) (b) figure 13. visualization of nickel (a) before loading with (b) after loading at a temperature of 300 k figure 13 shows that at a temperature of 300 k, nickel metal is composed of a uniform crystal structure with a percentage of the fcc crystal structure of 100%. in contrast to the case when the crystal structure of nickel metal is no longer uniform after loading. this was evidenced by the cna display, which showed the percentage of hcp's crystal structure was 14.3%, the fcc was 55.8%, and 30% for the crystal structure that was undefined. green shows the fcc's crystal structure, red shows the crystal structure of the hcp, and gray shows the crystal structure that is undefined. at a temperature of 300 k, it can be seen that the atoms making up the nickel-metal material are still in the solid phase. this is indicated by the absence of a cavity or free space in the simulation box, where the space indicates that the metal system has undergone a phase change, although not entirely. in addition to the temperature of 300 k, the nickel-metal state at 1723 k can be observed based on figure 14. (a) (b) figure 14. visualization of nickel (a) before loading with (b) after loading at a temperature of 1723 k figure 14 shows that at 1723 k, nickel metal is composed of a small portion of the fcc crystal structure, namely 1% and 99% of the crystal structure is undefined. in contrast to the case when after loading, the nickel-metal's crystal structure becomes uniform, namely 100% composed of an undefined crystal structure. at a temperature of 1723 k, it can be seen that the atoms making up the nickel-metal material have undergone a phase change from solid to liquid. this is indicated by a cavity or free space on the edge of the simulation box. microscopically, metals in the solid phase are composed of atoms with binding energy greater than those in the liquid phase. this shows that the atoms' binding energy making up the nickel-metal at a temperature of 1723 k has a relatively small value, causing the distance between the atoms and the volume 33 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 of the system to be much larger than in the solid phase. the profile of the effect of temperature variations on copper, silver, gold, and aluminum materials is the same as for nickel metal. the other four materials' visualization is shown in the visualization of the effect of temperature on the pure metal material system. conclusions the research's success can be reviewed based on young's modulus value of the five materials according to the experimental results, namely with a discrepancy value of less than 2%. also, the accuracy of selecting the interatomic potential function based on the appropriate parameters is an essential factor in obtaining precise and accurate results, which in this study uses the morse potential, which is suitable for metallic materials in the solid phase. the simulation of the calculation of young's modulus value is carried out using the molecular dynamics method. this method can be developed in more complex cases, one of which is the stiffness of alloys and composites. references [1] d c giancoli, 1998, physics: fifth edition, new jersey: prentice-hall. inc. [2] e p popov, 1996, mekanika teknik edisi kedua, jakarta: erlangga. [3] g s camprubi, 2011, mechanical properties at nano-level, tesis, sweden: lund university. [4] a l ferguson, 2014, elements of icme research workshop molecular dynamics with lammps, urbana-champaign: university of illinois. [5] h d young and r a freedman, 2002, fisika universitas edisi kesepuluh jilid 1, jakarta: erlangga. [6] s p hannula, k s kim, j y song, e k chung, j k park, and s h hong, 2006, relationship between mechanical properties and microstructure of ultra-fine gold bonding wires, mechanics of materials, volume 38, page 119–127. [7] z l greer, 2011, temperature. frequency. and young’s modulus of an aluminum tuning fork, isb journal of physics, volume 5 (1), page 1-4. [8] w d j callister and d g retwisch, 2007, an introduction materials science and engineering seventh edition, new york: john wiley& sons. inc. [9] g l j vliet and w both, 1984, teknologi untuk bangunan mesin bahan-bahan i. cetakan ke-1. instead language by haroen, jakarta: erlangga. [10] m born, 1981, diffusion activation energies in face-centered cubic metals using the mors potential function, journal of physics, volume 19 (4). [11] c kittel, 1996, introduction to solid state physics seventh edition, usa: john wiley & sons. inc. 34 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 1, page 19 – 34 submitted : march 11, 2019 accepted : april 21, 2019 online : may 2, 2019 doi : 10.19184/cerimre.v2i1.20557 [12] s olliges, p a gruber, v auzelyte,y ekinci, h solak and r spolenak, 2007, tensile strength of gold nanointerconnects without the influence of strain gradients, acta materialia, volume 55. page 5201–5210 [13] h babayi, 2004, the antimicrobial activities of methanolic extract of eucalyptus camaldulensis and terminalia catappa againt some pathogenic microorganisms. an int. j. niger. soc. for experiment. bio, volume 16 (2), page 106-111. [14] s j chen and h l huang, 1981, diffusion activation energies in face-centered cubic metals using the mors potential function, journal of physics, volume 19 (4), page 106112. [15] t surdia and s saito, 1999, pengetahuan bahan teknik cetakan ke-4, jakarta: pt. padnya paramita [16] j e huheey and r l keither, 1993, inorganic chemistry fourth edition, new york: hampercollies college publisher. [17] a arkundato, z su’ud, m abdullah, w sutrisno, m celino, 2013, inhibition of iron corrosion in high temperature stagnant liquid lead: a molecular dynamics study, annals of nuclear energy 62, 298-306, december 2013 [18] d c rapaport, 2004, the art of molecular dynamics simulation, cambridge: cambridge university press. [19] oxtoby, gillis, and nachtrieb, 2001, prinsip-prinsip kimia modern edisi keempat jilid 1, translate by suminar. jakarta: erlangga. iii computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1 may – 2022 eissn 2747-173x editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah endhah purwandari wenny maulina yoyok yulianto muhayat zamroni wiwin ro’inah computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index table of contents volume 5, issue 1 may – 2022 eissn 2747-173x page cover i table of contents ii editorial board iii high-efficiency dye-sensitized solar cells: a comprehensive review ankit stephen thomas 1-29 future of oil and renewable energy yousof gholipour 30-37 study of the contrast observed on carbon by monte carlo simulation on wet-stem tomography rahmat firman septiyanto and isriyanti affifah 38-47 interaction between liquid lead and feni material using molecular dynamics simulation feryna ramadhany, misto, tri mulyono and moh. hasan 48-55 neutron mean free path in the slab reactor core using one-dimensional multi-group diffusion equation putri nabila, mohammad ali shafii, and seni herlina j. tongkukut 56-62 effect of corrosive liquid lead coolant on structural stability of iron material sudarmadi, sutisna, bowo eko cahyono and widiasih 63-67 energy yield of the carbonized plant leaf, petiole and branch biomass briquettes for sustainable production of future fuels arry y nurhayati, ach. zulfi n naufal and yuda c hariadi 68-77 56 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 optimation of layers thickness design of perovskite solar cell (psc) using gpvdm simulation dita puspita 1,a 1 department of physics, faculty of mathematics and natural sciences, universitas jember, jalan kalimantan no. 37 jember 68121 a ummushafiyyah88@gmail.com abstract. in this research, perovskite solar cells by configuring ito/pedot:pss/ch3nh3pbi3/zno/al changed to optimize their performance. modifications are made by varying the thickness of each layer to increase the ideal thickness with an optimal power conversion efficiency (pce) value. this research used gpvdm software to study several power conversion efficiency (pce) parameters of ito/pedot:pss/ch3nh3pbi3/zno/al solar cells. the results of the study show that the power conversion efficiency (pce) can be increased by adjusting the thickness of the coating, in this study the ideal thickness with the highest power conversion efficiency 25.75% in 1x10 -8 m of ito, 1x10 -6 m of pedot:pss, 4x10 -7 m of ch3nh3pbi3, 1x10 -8 m of zno and 1x10 -9 m of al. keywords: psc, pce, gpvdm software, layer thickness modification introduction solar energy is a reliable alternative energy source because it is abundant and environmentally friendly. in this perspective, developing solar cells is one of the best approaches to convert solar energy into electrical energy based on the photovoltaic effect. until now, the advancement of solar cell technology is growing so rapidly. for many years, silicon-based solar cells have been used for industrial purposes with efficiencies reaching 30%, especially crystalline silicon-based solar cells [1]. but behind its advantages are high production costs and are difficult for large industries to use. another alternative is third-generation solar cells. third-generation solar cells are capable of producing photo-to-electricity conversion devices with high efficiency and much lower production costs. there are several classifications of technologies included in the third generation of solar cell technology, including dye-sensitive solar cells, quantum dot solar cells (qds), and perovskite-sensitive solar cells [2]. of the three types of solar cells included in this third-generation solar cell technology, perovskite-based solar cells appear to have a very good opportunity to contribute to large-scale solar energy production based on high pce and compatibility with scalable processes. however, there are challenges in the perovskite-based solar cell production process, namely long-term stability [3]. various efforts have been made to maximize the efficiency of perovskite-based solar cells. in research on solar cells based on ch3nh3pbbr3 with a high photovoltage of 0.96 v and the value of the efficiency is 3.8% [4]. in a study on ch3nh3pbi3 measuring 2-3 nm and giving an efficiency of 6.54% [5]. in different studies achieved an astonishing efficiency of 16.2% [6]. study on the effect of layer thickness on the power conversion efficiency of ch3nh3pbi3 based planar heterojunction solar cells and the results showed by adjusting layer thickness in our case power conversion efficiency was increased from 9.96 % to 12.9 % [7]. and in a study on the ch3nh3pbi3 thickness effect on device efficiency in planar heterojunction perovskite solar cells showed the optimization of the layer thickness yielded devices with efficiencies of up to 11.3%. the results further demonstrate mailto:ummushafiyyah88@gmail.com 57 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 that a delicate balance between light absorption and carrier transport is required in these planar heterojunction devices, with the thickest perovskite films producing only very low power conversion efficiencies [8]. different parameters can increase the pce of perovskite-based solar cells, one of which is the effect of layer thickness. this research used gpvdm which is a software simulator for photovoltaic, were investigated the effect of layer thickness on pce in ito/pedot:pss/ch3nh3pbi3/zno/al solar cells and obtained the ideal thickness. theoretical background general purpose photovoltaic device (gpvdm) is a 1d/2d optoelectronic device model, which can be used to simulate solar cells, leds, diodes, fets, etc. simulations were carried out using the general purpose photovoltaic device model (gpvdm). this simulator is based on solving poisson equation (1) to obtain voltage , ( ) ( ) (1) where front anode ( ) dan back cathode ( ), is the permittivity of free space, is relative permittivity, is the elementary charge, and is free electron and hole population. something not less important in solar cells is the offset of band edges of the homo and lumo levels will prove responsible for the improvement of all photovoltaic properties of the organic solar cells. since a deep homo level is desirable for obtaining high open-circuit voltage (voc) since the maximum value of the voc is determined by the energy difference between the homo (highest occupied molecular orbital) level of the donor and lumo (lowest unoccupied molecular orbital) level of the acceptor. drift diffusion equation (momentum conservation equation) for electron: (2) for hole: (3) dan define the carrier mobility and define and , where is a difference of lumo mobility and vacuum level and is a difference of homo and lumo mobility. to describe carrier trapping, d-trapping recombination used srh recombination model for electron and hole, which assume a steady-state distribution of trapped charge carries in the trap states. * ( )+ ( ) (4) 58 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 this form of the srh equation is therefore not suitable for time-domain simulations, where trapping or recombination via trap states dominate charge dynamics. as the charge carriers can not go out of equilibrium [9]. so, to solve the charge density of each trap state explicitly needed to split space up the energy into energy slice and use srh equations but don’t assume steady-state so solved the srh equation explicitly in the time domain. each trap state gets its rate equation (5) rec is the rate at which free electrons get trapped, ree is the rate at which electrons can escape from the trap back to the free electron population, rhc is the rate at which free holes get trapped and rhe is the rate at which holes escape back to the free hole population. electron recombination rate (re) in equation (2) can be calculated by subtracting the total number of electrons that escape all traps into the carrier free electron population from the total number of electrons captured from the free carrier population into all traps. an analogous procedure is carried out to calculate rh for free holes. more detailed equation resolving and device modeling can be found in more detail in [10, 11, 12-16]. materials and methods figure 1, shows the design of ito/pedot:pss/ch3nh3pbi3/zno/al solar cells in this research. table 1 is shown initial parameters that were carefully picked from practical and theoretical references. figure 1. desain of ito/pedot:pss/ch3nh3pbi3/zno/al solar cells in this research table 1. simulation parameters parameters ito [7] pedot:pss [12] ch3nh3pbi3 [7] zno [13] layers thickness (m) 1x10 -7 2x10 -7 4x10 -7 2x10 -7 electron mobility (m 2 /v.s) 6.86x10 -7 0.002 0.002 0.02 hole mobility (m 2 /v.s) 3.75x10 -2 0.002 0.002 0.018 relative permittivity ԑr 3 3 20 2250 eg (ev) 0 1.6 2.1 3.35 electron affinity (ev) 4.7 1.6 1.6 4.3 donor concentration (m -3 ) 5x10 26 5x10 25 5x10 25 5x10 25 acceptor concentration (m -3 ) 5x10 26 5x10 25 5x10 25 5x10 25 59 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 this simulation research is based on the study of the effect of different thicknesses on power conversion energy (pce). initial thickness given in table 1 yields power conversion energy 7.2%, fill factors is 55.12%, open circuit voltage is 0.974 v, and short-circuits density of current is -134 a/m 2 . results and discussion optimation of the thickness of every layer was carried out in this research to obtain the ideal thickness of ito/pedot:pss/ch3nh3pbi3/zno/al solar cells. modifications are made one by one on every layer thickness parameter to get the maximum pce value. figure 2 is presented the curve of the effect of ito layers thickness on pce. figure 2. effect of ito thickness on pce figure 2 shows the effect of ito thickness on pce. the ito layer thickness of 1x10 -8 m has a maximum pce value of 7.46%, with a fill factor of 55.05%, an open circuit voltage of 0.975 v, and a short-circuit density of current of -139.04 a/m 2 . so, ito layer with a thickness 1x10 -8 m was set and further modified the pedot:pss layer thickness was to obtain the curve in figure 3. 60 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 figure 3. effect of pedot:pss thickness to pce from figure 3 the maximum pce on pedot:pss layer at 1x10 -6 m thickness shows 23.59%, with a fill factor is 76.1%, open circuit voltage is 1 v, and a short-circuit density of current of 312.8 a/m 2 . pedot:pss layer thickness was set to 1x10 -6 m, then ch3nh3pbi3 layer thickness was modified and obtained curve in figure 4. figure 4. effect of ch3nh3pbi3 thickness on pce in figure 4 the maximum pce is 23.89% in the ch3nh3pbi3 layer thickness of 4x10 -7 m, with fill factor 76.11%, an open circuit voltage of 1.003 v, and short-circuit density of current of -312.9 a/m 2 . 61 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 at 4x10 -7 m thickness, the ch3nh3pbi3 was set and modified the zno layer thickness to obtained curve in figure 5. figure 5. effect of zno thickness on pce figure 5 shows the maximum pce of 25.65% at 1x10 -8 m zno layer thickness, where fill factor of 87.74%, an open circuit voltage of 1.004 v and short-circuit density of current of -291 a/m 2 . the last, after fixed the zno layer thickness at 1x10 -8 m, the al layer thickness gets modified to obtain the curve in figure 6. figure 6. effect of al thickness on pce 62 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 the curve of figure 6 shows the maximum pce of 25.75% is obtained in al layer thickness of 1x10 -9 m. the fill factor is 88%, an open circuit voltage is 1.005 v and the short circuit density of current is -292.1 a/m 2 . from figures 2 to 6 could be presented the thickness optimation of every layer give effect to pce value and the ideal layer thickness of ito/pedot:pss/ch3nh3pbi3/zno/al solar cells design with optimum pce value: ito layer thickness of 1x10 -8 m, pedot:pss layer thickness of 1x10 -6 m, ch3nh3pbi3 layer thickness of 4x10 -7 m, zno layer thickness of 1x10 -8 m and al layer thickness of 1x10 -9 m. from the layer thickness optimation, pce value increased from 0.1% to 25.75%. conclusions ito/pedot:pss/ch3nh3pbi3/zno/al power conversion efficiency was analyzed using the gpvdm solar cell software simulation. results show that a good choice of the layer thickness of different materials used in the solar cell increases considerably the pce ratio. simulation results show that an improvement at ito layer thickness of 1x10 -8 m, pedot:pss layer thickness of 1x10 -6 m, ch3nh3pbi3 layer thickness of 4x10 -7 m, zno layer thickness of 1x10 -8 m, and al layer thickness of 1x10 -9 m. it has 25.75% of pce value. further pce enhancements can be optimized by changing layer structure and materials. references [1] national renewable energy laboratory (nrel), 2018, best research-cell efficiency chart, executive summary on https://www.nrel.gov/pv/cellefficiency.html accessed on june 5, 2018. [2] g. coonibear, 2007, third generation photovoltaics, materials today, volume 10 (11), page 42-50. [3] m. alfaz, bagawan and g. kaveri s, 2017, perovskite solar cells, international journal of advance research in science and engineering (ijarse), issn: 2314-8354, volume 6, issue 10. [4] a. kojima, k. teshima, y. shirai and t. miyasaka, 2009, organometalhalide perovskites as visible-light sensitizers for photovoltaic cells, journal of the american chemical society, volume 131, no. 17, page 6050-6051. [5] j.h. im, c.r. lee, j.w. lee, s.w. park and n.g. park, 2011, 6.5% efficient perovskite quantum-dot-sensitized solar cell, nanoscale, volume 3, no. 10, page 4088-4093. [6] m. a. green, a. ho-baillie and h. j. snaith, 2014, the emergence of perovskite solar cells, nature photonics, volume 8, no. 7, page 506–514. [7] a. hima, a. khechekhouche, i. kemerchou, n. lakhdar, b. benhaoua, f. rogti, i. telli and a. saadoun, 2018, gpvdm simulation of layer thickness effect on power conversion efficiency of ch3nh3pbi3 based planar heterojunction solar cell, international journal of energetica (ijeca). issn: 543-3717, volume 3, issue 1. [8] l. dianyi, g. mahesh k and k. timothy l, 2014, effect of ch3nh3pbi3 thickness on device efficincy in planar heterojunction perovskite solar cells, journal of materials chemistry a: royal society of chemistry. [9] m. roderick c. i, 2018, gpvdm user manual, https://www.gpvdm.com/docs/educators/workbook/workbook.pdf accessed on april 6, 2018. https://www.nrel.gov/pv/cellefficiency.html%20accessed%20on%20june%205 https://www.gpvdm.com/docs/educators/workbook/workbook.pdf%20access%20on%20april%206 63 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 56-63 eissn : 2747-173x submitted : june 28, 2019 accepted : september 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27366 [10] r. c. i. mackenzie, t. kirchartz, g. f. a. dibb, and j. nelson, 2011, modeling nongeminate recombination in p3ht:pcbm solar cells, j. phys. chem. c, volume 115, no. 19, page 9806–9813. [11] f. deschler, d. riedel, b. ecker, e. von hauff, e. da como, r.c.i. mackenzie, 2012, increasing organic solar cell efficiency with polymer interlayers, phys. chem, volume 15, no. 3, page 764-769. [12] r. c. i. mackenzie, c. g. shuttle, m. l. chabinyc and j. nelson, 2012, extracting microscopic device parameters from transient photocurrent measurements of p3ht:pcbm solar cells, advanced energy materials, volume 2, no. 6, page 662-669. [13] s. m. sze and k. n. kwok, 2007, physisc of semicondctor device, new jersey, john wiley and sons inc. [14] f. hao et al, 2014, lead free solid state organic–inorganic halide perovskite solar cells, nature photonics, volume 8, no. 6, page 489. [15] t. minemoto and m. murata, 2015, theoretical analysis on effect of band offsets in perovskite solar cells, solar energy materials and solar cells, volume 133, page 8-14. [16] p. umari, e. mosconi and f. de angelis, 2014, relativistic gw calculations on ch3nh3pbi3 and ch3nh3sni3 perovskites for solar cell applications, scientific reports, volume 4, page 4467. iii computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2 november – 2022 eissn 2747-173x editor in chief artoto arkundato editor lutfi rohman ratna dewi syarifah endhah purwandari wenny maulina yoyok yulianto muhayat zamroni wiwin ro’inah computational and experimental research in materials and renewable energy (cerimre) published by: faculty of mathematics and natural sciences, university of jember published since november 2018 with frequency of publication twice a year (may and november). editorial address : kampus tegal boto jl. kalimantan 37 kampus tegalboto 68121 telp. +62331 334293 faks. +62331 330225 email: cerimre.journal@unej.ac.id url: https://jurnal.unej.ac.id/index.php/cerimre/index 64 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 study of neptunium, americium and protactinium addition for 300mwth gfr with uranium carbide fuel ratna dewi syarifah 1,a and alvi nur sabrina 2 1 department of physics, faculty of mathematics and natural sciences, universitas jember, jalan kalimantan no. 37 jember 68121 a rdsyarifah.fmipa@unej.ac.id abstract. a study of neptunium, americium, and protactinium addition for gfr 300mwth with uranium carbide fuel has been performed. the purpose of this study was to determine the characteristics of addition neptunium, americium, and protactinium in a 300mwth gas-cooled fast reactor. neutronics calculation was design by using standard reactor analysis code (srac) version 2006 with data nuclides from jendl-4.0. neutronics calculations were initiated by calculating the fuel cell calculation (pij calculation) and continued with the reactor core calculation (citation calculation). the reactor core calculation used two-reactor core configurations, namely the homogeneous core configuration and heterogeneous core configuration. the neptunium, americium, and protactinium additions were performed after obtaining the optimal condition from heterogeneous core configuration. the addition of neptunium and americium which are spent nuclear fuel (snf) from lwr fuels, aims to reduce the amount of neptunium and americium in the world and also to reduce the effective multiplication factor (keff) value from the reactor. the results obtained that the addition of neptunium and americium causes the k-eff value was decreased at the beginning of burn-up time, but increase at the end of burn-up time. it was because neptunium and americium absorb neutrons at the beginning of burn-up time and turns into fissile material at the end of burn-up time. the addition of protactinium in the reactor causes the k-eff value to be decreased both at the beginning of the burn-up time and at the end of the burn-up time. it happens because protactinium absorbs neutrons both at the beginning of the burn-up time and at the end of the burn-up time. therefore protactinium is often called a burnable poison. keywords: gfr, uranium carbide, neptunium, americium, protactinium introduction nuclear reactor generation iv are reactors formed from the development of generation iii + reactors. generation iv reactor consists of six reactor types, i.e. gas-cooled fast reactor (gfr), lead cooled fast reactor (lfr), molten salt reactor (msr), sodium cooled fast reactor (sfr), supercritical water-cooled reactor (scwr), and very high-temperature reactor (vhtr). there are several advantages of generation iv reactors, i.e. inherent safety, sustainability, non-proliferation resistances, and economic competitiveness [1-2]. a gas-cooled fast reactor (gfr) is one of the gas reactors that emerged as the generation iv reactors. gfr is one candidate for generation iv nuclear power reactor which is estimated to be used in 2030. neutronic calculation about gfr with uranium plutonium nitride and thorium nitride as a fuel has been calculated before with varies of power, geometry, and actinide minor addition [3-12]. in this study, the neutronics calculation of gfr used uranium carbide as fuel and added neptunium, americium, and protactinium as spent nuclear fuel. the purpose of this study was to determine the characteristics of the addition of neptunium, americium, and protactinium on uranium carbide fuel. the addition of minor actinides on the fuel used in the modular gas 65 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 cooled fast reactor is one of the right actions to reduce the waste of residual lwr fuel in the world. theoretical background a nuclear reactor is a controlled fission chain reaction. based on the neutron energy used to maintain the fission reaction, there are two types of reactor, i.e. thermal reactors and fast reactors. gfr is a reactor that uses a fast neutron spectrum and uses a coolant in the form of helium (he). the high temperature generated in the gfr, allows this reactor to be used as a power plant in the future. the addition of minor actinides, which are recycled fuels from lwr waste, has the advantage of reducing radioactive waste in the world. the neptunium and americium have a large percentage of lwr used fuel and have a half-life of hundreds to millions of years [13]. neutronics calculation in the nuclear reactors can be performed using the following programs, i.e. relap, origin-8, autocad 20108, labview, arcgis-10, understand 2.6, matlab, srac, etc. [14]. neutronics calculation in this study was performed by using the standard reactor analysis code (srac) which is a program of code analysis and design for nuclear reactors. srac has a library or data set on neutron cross-section, additional codes used in the analysis of nuclear reactor design, routines or movements of the neutron spectrum, neutron transport, one group – multi-group diffusion, etc. [15]. the database was used in the srac code, i.e. jendl, endf/b, and jef which have more than 300 nuclide data. this study using srac ver 2006 with the jendl-4.0 database which is the latest version of nuclide data from jendl. materials and methods table 1 shows the reactor design specifications. the specifications include the specification of the core and the fuel that had been used. the fuel cell pin used in this study is the hexagonal cell. the hexagonal cell geometry in this study is divided into six regions, the first three are fuel regions, the next two regions are cladding, and the next two regions are coolant. the division of the region can be seen in figure 1 and the sub-region from hexagonal cell geometry can be seen in figure 2. table 1. reactor design specifications no. parameter specification 1. fuel /cladding /coolant uc/ sic/ he 2. fuel volume fraction 60% 3. cladding volume fraction 10% 4. coolant volume fraction 40% 5. minor actinide neptunium-237 and americium 6. pin pitch 1.45 cm 7. burnable poison protactinium-231 8. percentage u-235 5% 15% 9. percentage protactinium-231 0.5% 4% 10. percentage neptunium-237 0.5% 5% 11. percentage americium 0.5% 5% 12. power 300 mwth 13. burn-up time >20 years 14. core geometry cylinder pancake 15. fuel pin cell hexagonal cell 16. height active core 100 cm 17. diameter active core 240 cm 18. reflector 50 cm 66 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 rx fuel cladding coolant figure 1. regional division in fuel pin calculation figure 2. sub-region hexagonal cell geometries the calculation method uses srac 2006 with the jendl-4.0 database. the first step of calculation was the calculation of fuel pin cell (pij calculation) and the second step was reactor core calculation (citation calculation). the calculation for pij and citation used two core configurations, i.e. homogeneous and heterogeneous core configurations. the homogeneous core configuration used one type of percentage of uranium-235. and the heterogeneous core configuration used three types of the percentage of uranium-235 in the reactor core. the uranium-235 is used as fissile material in the reactor core. results and discussion the neutronics calculation began with the calculation of the homogeneous core configurations. the homogeneous core configurations used percentage 5% 15% of uranium-235. the results obtained indicate that the fuel variations with the average u-235 value of 12% showed the most critical condition. based on the results of the homogeneous core configuration i.e. percentage 12% of u-235, it became referred to as calculate heterogeneous core configuration. table 2 shows fuel variations used in the calculations of heterogeneous core configurations. table 2. variation of u-235 in heterogeneous core calculation number of case composition (%) case 1 f1=10%, f2=12%, f3=14% case 2 f1=9%, f2=12%, f3=15% case 3 f1=11%, f2=12%, f3=13% case 4 f1=10.5%, f2=12%, f3=13.5% case 5 f1=9.5%, f2=12%, f3=14.5% figure 3 shows the result of heterogeneous core configuration. the result shows that variations in case 2 (f1=9%, f2=12%, f3=15%) are the variation with the most stable k-eff value from the center 2 1 3 4 5 6 67 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 beginning till the end of burn-up time. maximum excess reactivity obtained on average 6% ∆k/k%. figure 4 shows the comparison of average power density in homogeneous and heterogeneous core configurations. the average power density in homogeneous core configuration has a peaking power in the center of the reactor core, while in heterogeneous core configuration has a flat value of average power density in the center of the reactor core. based on the results obtained, the average power density in the heterogeneous core configuration indicates a safer condition to using in the operation of the reactor. therefore, the calculation in the next step uses a core with a heterogeneous configuration. the comparison of average power density value and maximum power density value in homogeneous and heterogeneous core configurations are shown in table 3. figure 3. effective multiplication factor (k-eff) value of heterogeneous core configuration 0 5 10 15 20 1.058 1.060 1.062 1.064 1.066 1.068 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (year) f1=10%,f2=12%,f3=14% f1=9%,f2=12%,f3=15% f1=11%,f2=12%,f3=13% f1=10.5%,f2=12%,f3=13.5% f1=9.5%,f2=12%,f3=14.5% 68 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 figure 4. comparison of average power density value in homogeneous core configuration and heterogeneous core configuration table 3. comparison of average power density and maximum power density in homogeneous and heterogeneous core configuration core configuration case average power density (watt/cc) maximum power density (watt/cc) homogeneous u-235 12% 87.9 175 heterogeneous f1=9%, f2=12%, f3=15% 78.6 97 after calculated heterogeneous core configuration, it was necessary to add neptunium-237 and americium in the reactor. neptunium-237 and americium are one of minor actinide nuclide. minor actinides are residual fuel obtained from light water reactor (lwr) waste. minor actinides are commonly referred to as spent nuclear fuel (snf) which has a relatively long half-life and a high level of toxicity. this study used the minor actinides of the nuclides neptunium-237 and americium because it was the most abundant lwr fuel waste. figure 5 and 6 shows the effective multiplication factor (k-eff) value of neptunium and americium addition in the uc fuel. 5 10 15 20 25 30 0.0 0.5 1.0 1.5 2.0 a v e ra g e p o w e r d e n s it y a lo n g r o w ( w a tt /c c ) radial mesh (cm) homogen heterogen 69 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 figure 5. effective multiplication factor (k-eff) value of neptunium addition in the uc fuel figure 5 and 6 shows that neptunium-237 and americium decreased the k-eff values at the beginning of the burn-up time and increased the k-eff value at the end of burn-up time. the greater variation of the neptunium-237 and americium given, the greater decreased of k-eff value at the beginning of burn-up time. it happened because neptunium-237 and americium has cross-section absorption greater than fissile material. therefore, the k-eff value decreased at the beginning of burn-up time. after absorbing the neutrons, the neptunium-237 and americium would become fissile material (pu-239), so at the end of burn-up time the k-eff value increase. figure 6. effective multiplication factor (k-eff) value of americium addition in the uc fuel 0 5 10 15 20 1.025 1.030 1.035 1.040 1.045 1.050 1.055 1.060 1.065 1.070 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (year) neptunium 0.5% neptunium 1% neptunium 1.5% neptunium 2% neptunium 2.5% neptunium 3% neptunium 3.5% neptunium 4% neptunium 4.5% neptunium 5% 0 5 10 15 20 1.01 1.02 1.03 1.04 1.05 1.06 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (year) americium 0.5% americium 1% americium 1.5% americium 2% americium 2.5% americium 3% americium 3.5% americium 4% americium 4.5% americium 5% 70 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 after that, it was necessary to add burnable poison in the core reactor to decrease k-eff value to become critical. the burnable poison used in this study is protactinium (pa-231). protactinium has high cross-section neutron absorption. pa-231 absorbed neutrons at the beginning of the burn-up time, causing the k-eff value was decreased. figure 7 shows the result of heterogeneous core configuration with the addition of pa-231. the variation of pa-231 used between 0.5% up to 4% with an interval 0.5. the addition of pa-231 3.5% had the optimum k-eff value (k-eff ~ 1) with a maximum excess reactivity obtained 1.04% ∆k/k%. figure 7. effective multiplication factor (k-eff) value of addition protactinium-231 conclusions neptunium-237 and americium decreased the k-eff value at the beginning of burn-up time and increased the k-eff value at the end of burn-up time. at the beginning of burn-up time, the neptunium-237 and americium absorbed the neutron and become fissile material (pu-239 and pu-241). therefore it increased the burn-up time at the end of burn-up. protactinium is called burnable poison. it decreased the k-eff value both at the beginning and the end of burn-up time. references [1] gif (the generation iv international forum) and the oecd nuclear energy agency, 2014, technology roadmap update for generation iv nuclear energy system. [2] gif (the generation iv international forum) and the u.s doe nuclear energy advisory commite, 2002, a technology roadmap for generation iv nuclear energy system. [3] r. d. syarifah, y. yulianto, z. su’ud, k. basar, and d. irwanto, 2016, neutronic analysis of thorium nitride (th, u233)n fuel for 500 mwth gas cooled fast reactor (gfr) longlife without refueling, key engineering materials, vol. 733, page 47-50. 0 5 10 15 20 1.00 1.01 1.02 1.03 1.04 1.05 1.06 e ff e c ti v e m u lt ip li c a ti o n f a c to r (k -e ff ) burn-up time (year) pa 0.5% pa 1% pa 1.5% pa 2% pa 2.5% pa 3% pa 3.5% pa 4% 71 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 64-71 eissn : 2747-173x submitted : july 8, 2019 accepted : september 8, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27368 [4] r. d. syarifah, z. su’ud, k. basar, and d. irwanto, 2016, design study of 200 mwth gas cooled fast reactor with nitride (un-pun) fuel long life without refueling, matec web of conferences. [5] r. d syarifah, z. su’ud, k. basar, and d. irwanto, 2016, the prospect of uranium nitride (un-pun) fuel for 25-100 mwe gas cooled fast reactor long life without refueling, journal of physics, conference series 776. [6] r. d syarifah, z. su’ud, k. basar, and d. irwanto, 2017, fuel fraction analysis of 500 mwth gas cooled fast reactor with nitride (un-pun) fuel without refueling, iop conf. series : journal of physics, conference series 799. [7] r. d. syarifah, z. su’ud, d. irwanto, k. basar, s. c. pattipawaej, and m. ilham, 2017, comparison of uranium and thorium nitride fuel for 500 mwth gas cooled fast reactor (gfr) longlife without refueling, international journal of research, special issue paper, page 1-7. [8] r. d. syarifah, z. su’ud, k. basar, and d. irwanto, 2017, comparative study on various geometrical core design of 300 mwth gas cooled fast reactor with un-pun fuel longlife without refueling, iop conf. series : journal of physics, conference series 877. [9] r. d. syarifah, z. su’ud, k. basar, and d. irwanto, 2018, neutronic analysis of un-pun fuel use fi-itb-chi code for 500 mwth gfr long-life without refueling, iop conf. series:journal of physics, conf. series 1090. [10] m. a. fareha, r. d. syarifah, z. su’ud, k. basar, and n. kuniarsih, 2018, design study of 600 mwt long-life modular gas cooled fast reactors, iop conf. series : journal of physics : conf. series 1090. [11] r. d. syarifah, 2018, design and neutronic analysis nuclear power modular reactor type gfr (gas cooled fast reactor) without refueling, disertasi, fmipa-fisika : institute technology bandung. [12] z. su’ud, 2014, design study of small gas cooled fast nuclear power plant for synergic energy system with renewable energy by employing pump storage, advanced material research, vol. 983, page 233-237. [13] iaea, 2009, status of minor actinide fuel development, vienna : international atomic energy agency, issn : 1995-7807. [14] k. tsuchihashi, h. takano, k. horikami, y. ishiguro, k. kaneko, and t. hara, 1983, srac : jaeri thermal reactor standard code system for reactor design and analysis, japan : japan atomic energy research institue (jaeri). [15] k. okumura, t. hugo, k. kaneko, and k. tsuchihashi, 2002, srac (ver. 2002): the comprehensive neutronics calculation code system, japan : japan atomic energy research institue (jaeri). table of contents volume 5, issue 2 november – 2022 eissn 2747-173x page cover i table of contents ii editorial board iii optical ray tracing simulation by using monte carlo method for reflectance-based photoplethysmography sensor in human skin and fingertip model muhamad affiq bin misran, anubha bilgaiyan, and reiji hattori 78-91 environmental radioactivity concentrations and assessment of radiological hazards in soil around bandung nuclear area juni chussetijowati, haryo seno, dani muliawan 92-104 innovative compact molten salt reactor (icmsr) analysis for mo-99 production iza shafera hardiyanti, a suparmi and andang widi harto 105-113 analytical methods for mathematical modeling of dye-sensitized solar cells (dsscs) performance for different local natural dye photosensitizers j. b. yerima, s. c ezike, dunama william, and alkali babangida 114-132 a brief review on the electrical resistivity of aluminium alloy and its nanoparticles at low temperature inzamam khalid 133-141 photo electrochemically manufactured hgo/cu2o monolayer with augmented photovoltaic features m. abdurrahman, f.w burari, and o.w olasoji 142-151 60 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 neutronic analysis of the smart modular reactor fuel using srac 2006 nailatussaadah 1,a and irsyad 1 1 bandung triga 2000, directorate of nuclear management facilities, deputy for research and innovation infrastructure, national research and innovation agency, jl. tamansari no. 71, bandung, 40132, indonesia a nailatuss@yahoo.com abstract. neutronic analysis of the smart modular reactor fuel using srac 2006 has been carried out. electrical energy is important today because the need is increasing along with the increase in human population, advanced technology and the economy. on the other hand, there are demands from the community for the clean, efficient and consistent energy. this is the reason why nuclear power plants are considered as one of the candidates for electrical energy suppliers in indonesia in particular. this study evaluates a smart reactor with gadolinium as the burnable absorber material. the two kinds of fuel assembly were analyzed using the srac 2006 code system with the jendl 4.0 as nuclear data library. this study aims to observe the neutronic characteristics of the fuel assembly designs according to the reference used. the results of the study show that of all types of fuel assemblies used can reach criticality at the beginning of the operating cycle and last up to 3 till 5 years when it finally reaches subcritical condition. another parameter observed is the conversion ratio value, which from this study is in accordance with the characteristics of the conversion ratio for thermal reactors. keywords: smart, jendl 4.0, srac, neutronic. introduction it is fully realized that human beings are very dependent on energy, especially electrical energy. starting from primary needs to secondary human needs must be related to electrical energy. the state through the relevant ministries in charge of the energy sector must of course have a strategy so that energy needs are always met and predict future energy needs to avoid an energy crisis. the energy needs of a country normally will always increase every year along with the increase in population, economic growth, energy prices and technological developments [1]. the world's energy sector today is mostly driven by fossil fuel power generation. to address and meet national and global requirements for clean, efficient and consistent energy, energy production is designed to meet the growing energy demands of developing countries. new and innovative nuclear reactor technology needs to be developed. one of the initiations of this technological development is the potential utilization of modular nuclear reactors. it is the reactors with smaller size [2]. one of the power reactors candidates to be built in indonesia is the small modular reactor type. this reactor has several advantages such as the investment risk is not too high, advanced safety features, the size or dimensions of the reactor are not large, and is able to produce large 61 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 enough power in the same class as a power reactor with a size that is not too large in terms of physical appearance [3]. then the power reactors in the smr group have several types of designs from several countries, such as klt40s from russia, carem from argentina, htr-pm china or smart which is a reactor made by south korea. the smart type power reactor design has been used in saudi arabia, where in addition to being used for electricity production, this reactor is also used for seawater desalination [3]. this study aims to analyze the neutronic characteristics of each fuel assembly used in the smart reactor. the parameters observed were the multiplication factor, conversion ratio value, and changes in the density of important nuclides, such as u-235 and u-238. because in this study the characteristics of the fuel assembly were observed, which did not take into account the conditions around the core such as the reflector, the resulting and representative multiplication factor value was the k-inf value (infinite multiplication factor). while the value of keff (effective multiplication factor) is generated from the calculation of the core which will be carried out in further research. indirectly, this study is also used to observe the effect of the use of burnable absorber materials on fuel, where the absorber material used is gadolinium. this study uses a smart reactor with a thermal power of 330 mw and an operating cycle of 3 years for one core. the author uses the six types of fuel assemblies with specifications according to the reference. this reactor uses light water as the moderator. there are two types of fuel used, namely uo2 and uo2+gd2o3 [2]. the results of this study will be used for the core analysis. theoretical background the korean atomic energy research institute (kaeri) has been planning to build a smallpower modular reactor (smr) since 2012 [4-7]. this reactor is a 330 mw thermal integral reactor with one pressure vessel, and the main primary components such as steam generator inlet, eight steam generators, four reactor coolant pumps, assembly flow mixing header and flow skirt. reactor safety has been improved by reducing the frequency of core breakdown to 1/10 of the old type reactor. in some conditions the reactor can be extinguished by inserting a control rod or infusing boron [5-8]. the specification of smart reactor can be seen in table 1. table 1. specification of smart reactor no parameter value 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. thermal power (mw) electric power (mw) active core height (cm) type of fuel assembly pin pitch (cm) cladding type of fuel u-235 enrichment (%) burnable absorber gd percentage (%) cladding of gt and it 330 100 200 17 x 17 kofa 1.2598 zircaloy-2 uo2 < 5 gd2o3 8 zircaloy-4 62 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 the picture of the fuel assemblies of the smart reactor is as follows: figure 1. arrangement of ifba rods in different assemblies [2] 63 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 a complete description of each type of smart type nuclear reactor fuel device is shown in table 2. table 2. specification of fuel assemblies assembly uo2 enrichment (w/o) no. of standard fuel rods no. of gd fuel rods gd2o3 enrichment (w/o) a2 a3 b1 b2 b5 b6 2.82 4.88 256 252 260 256 244 240 8 12 4 8 20 24 8 8 8 8 8 8 the fuel assembly type a and b differ only in the active length of the fuel rod. this will be shown in figure 2. figure 2. ifba rod axial specifications [2] fuel assembly a2 is a fuel assembly with arrangement scheme and a type a for the fuel rod scheme. and so on for other types of fuel devices. 64 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 materials and methods figure 3 shows the flowchart of this research. the first step is to determine the type of fuel used, namely uo2. then, determine the burnable absorber material, this study used gd2o3 that is integrated into the uo2-gd2o3 fuel. the gadolinium was used with the consideration that this material has a very high neutron cross-section so it is very suitable if it is used as an absorber material [10]. furthermore, the cladding materials for both fuel and integrated burnable absorber materials are determined, namely zircaloy-2 and zircaloy-4. the next step is to determine the geometry of the fuel assembly, we used the symmetric square model. figure 3. flowchart of the study the calculation of the fuel assembly’s burnup in this study was carried out using the srac 2006 code system [11] and jendl 4.0 as the nuclide data library [12]. this calculation is carried out at the fuel assembly level using two-dimensional homogenization in the x and y directions. the calculation is also carried out with the initial assumption that the power generated from each fuel assembly is the same, resulting 330 mw for the core thermal power. this method is commonly used at the fuel assembly level. then, for the actual power produced by each fuel assembly, will be calculated in the core level, in which three-dimensional homogenization will be carried out. start determine the fuels determine the burnable absorber and cladding material determine the coolant material determine the fuel assembly geometry arrange the fuel rods and in the fuel assembly do the burnup calculations do the neutronic analysis finish 65 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 srac (standard reactor analysis code system) is a code system developed by jaeri (japan atomic energy research institute). this code is operated in the ubuntu system. the fuel assembly’s burnup is calculated using octane symmetric squares with a square pin model arrangement. then the fuel assemblies are arranged in the reactor core for the calculation using the citation module which is part of the srac 2006 code system. results and discussion the first neutronic parameter to be analyzed is the criticality. this criticality value is taken for each type of the fuel assembly, that is type a2, a3, b1, b2, b5 and b6. these fuel assemblies have different number of standard fuel and ifba (integrated fuel burnable absorber). while the gd content in each ifba is 8%. the infinite multiplication factor of each fuel assembly can be described as follows: figure 4. the k-infinite value to the burnup period (days) table 3. the k-infinite value day k-inf fa a2 fa a3 fa b1 fa b2 fa b5 fa b6 0 1.11396 1.06596 1.27687 1.23625 1.13088 1.09925 122 1.07007 1.03701 1.21439 1.18314 1.10111 1.07621 244 1.05952 1.03831 1.18589 1.16168 1.09685 1.07693 366 1.05281 1.04262 1.16138 1.14451 1.09748 1.08272 488 1.04126 1.03836 1.14007 1.12977 1.09933 1.08953 610 1.02092 1.01958 1.12045 1.11503 1.09755 1.09179 732 1.00064 0.99943 1.1013 1.09802 1.08735 1.08381 854 0.98222 0.98104 1.0821 1.07922 1.07046 1.06757 976 0.96546 0.96432 1.06357 1.06076 1.05245 1.0497 66 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 day k-inf fa a2 fa a3 fa b1 fa b2 fa b5 fa b6 1098 0.95014 0.94902 1.04606 1.0433 1.03517 1.03248 1220 0.93606 0.93498 1.02952 1.02683 1.01885 1.01621 1342 0.9231 0.92206 1.01388 1.01125 1.00343 1.00085 1464 0.91117 0.91016 0.99905 0.99647 0.98883 0.98629 1586 0.90018 0.8992 0.98495 0.98244 0.97497 0.9725 1708 0.89007 0.88912 0.97156 0.96911 0.96183 0.95941 1830 0.88076 0.87984 0.95883 0.95645 0.94935 0.947 figure 4 and table 3 present the infinite multiplication factor. figure 4 shows that at the beginning of the operating cycle, the six types of fuel assemblies have a k-inf value > 1.00 which means that criticality can be achieved. the graph decreases until it reaches a subcritical condition. the subcritical condition is not the same for each type, as showed in table 3, the fa a3 reached a subcritical condition around day 732, fa a2 on day 854, while the fa b1, b2, b5 and b6 lasted longer. the critical condition of a nuclear reactor represents that the reactor can maintain a nuclear fission chain. the reaction proceeds continuously as indicated by the k-inf value of 1.00. the fuel assembly type a has a smaller initial k-inf value than type b because the enrichment in type a fuel used is only 2.82% while for type b is 4.88%. the amount of u-235 as a fissile material in the fuel affects the number of fission reactions produced, which is described as the k-inf value. in figure 4 can also be seen that the decrease in the curve for fuel types a2, b1 and b2 tends to be smoother. from the beginning to the end of the cycle, the value of k-inf continues to decrease until it reaches a subcritical condition. it is different with fuel types a3, b5 and b6, where the curve decreases until a certain period then rises and finally decreases until it reaches a subcritical condition. this shows the effect of the amount of burnable absorber used. the fuel assembly type 1 uses only 4 ifba rods while type 2 uses 8 ifbas. fuel assembly type 3, 5 and 6 use more than that, that is 12, 20 and 24 ifba rods. the content of burnable absorber material in a fuel, will affect the number of fission reactions produced. the k-inf value curve for fuel assembly a3, b5 and b6, shown in figure 4, it decreases rapidly at the beginning of the cycle. this shows the very reactive characteristics of gd burnable absorber material. at a certain period, the gd material runs out so that the k-inf value increases, then the curve returns to decline, like a standard fuel assembly. burnable characteristic is to extend the life of a reactor operating cycle, so that in some of the latest generation reactors, this material has been inserted in the fuel. gd is one of the ba materials used in smr. the other parameter observed in this study is the conversion ratio. the conversion ratio is one of the benchmarks for reactor performance. the conversion ratio is the ratio of the fissile material number produced to the used/lost fissile material. the following is the conversion ratio of the fuel assemblies used in this study. 67 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 figure 5. conversion ratio to the burnup period (days) the conversion average value also can be seen in table 4. table 4. conversion ratio tipe perangkat bahan bakar rerata rasio konversi a2 0.8195 a3 0.8232 b1 0.6500 b2 0.6550 b5 0.6698 b6 0.6748 table 4 shows that the average conversion ratio of the fuel assemblies used is below 1.000. that means that the number of fissile material produced by this reactor is smaller than the fissile material used. this is also the characteristic of thermal reactors, the conversion ratio value < 1. in contrast to the breeding reactor which is able to produce its own fissile material so that it can extend the reactor operating period, the conversion ratio value is > 1. this study also conducted an analysis of changes in the important nuclides density, such as u235 and u-238. in the reactor, these nuclides are very influential because they determine the number of fission reactions that occur in the reactor. 68 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 figure 6. changes of u-235 nuclide density in the operation cycle figure 7. changes of u-238 nuclide density in the operation cycle the process of u-235 burning greatly affects the atomic density of the fuel. figures 6 and 7 show changes in the density of the u-235 and u-238 nuclides in the fuel assemblies during the operating period. the density of u-235 and u-238 nuclides experienced a less significant reduction, in the values of 10 -4 for u-235 and 10 -2 for u-238. the u-235 nuclide present in the fuel undergoes a fission reaction when it captures neutrons to produce other nuclides in the fuel. likewise, the u-238 nuclide, which is a fertile material, will produce other elements either through fission reactions or neutron absorption. 69 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 conclusions the results of the characteristic analysis of the fuel assemblies obtained from this study can be concluded as follows: 1. fuel assembly a2, a3, b1, b2, b5 and b6 can reach criticality early in the operating cycle; 2. the length of the operating cycle for fuel assembly a is less than 3 years while for type b is close to 5 years. seeing the character of light water reactors in general, these results are quite good, so it is hoped that the combination of these two types of fuel assembly in the core will be able to reach 3 years operating life of the reactor; 3. the conversion ratio value is less than 1.000 according to the characteristics of the thermal reactor; 4. important nuclides such as u-235 and u-238 experienced with not too large decline so that the core remained in a critical condition for longer time; 5. point number 4 is also affected by the number of burnable absorber contained in each fuel assembly. the greater the number of burnable absorber used, the longer the core can be maintained in a critical condition or the longer it’s operating cycle. acknowledgements the author would like to thank the director of nuclear management facility, mrs. vis wardhani as the research coordinator, wahid luthfi for his knowledge sharing and my colleagues in the reactor division for their support to the author until the completion of this study. references [1] m. carelli, g. garrone, m. mancini, m. trucco, and m. ricotti, 2010, economics features of integral, modular, small-to-medium size reactors, progress in nuclear energy, volume 52, page 403 – 414. [2] a. pourrostam, s. talebi, and o. safarzadeh, 2020, core analysis of accident tolerant fuel cladding for smart reactor under normal operation and rod ejection accident using dragon and parcs, nuclear engineering and technology, volume 53(3), page 741 – 751. [3] r. akbari-jeyhouni, o.d. rezaei, and a. gharib, 2018, assessment of an integral small modular reactor during rod ejection accident by using dragon/parcs codes, progress in nuclear energy, volume 108, page 136 – 143. [4] y.i. kim, y. bae, y.j. chung, and k.k. kim, 2015, cfd simulation for thermal mixing of a smart flow mixing header assembly, annals of nuclear energy, volume 85, page 356 – 370. [5] k. mehboob and m.s. aljohani, 2018, derivation of radiological source term of korean design system-integrated modular advanced reactor (smart), annals of nuclear energy, volume 119, page 148 – 161. [6] k.m. kim, b.i. lee, h.h. cho, j.s. park, and y.j. chung, 2011, numerical study on thermohydrodynamics in the reactor internals of smart, nuclear engineering design, volume 241, page 2536 – 2543. 70 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 60-70 eissn : 2747-173x submitted : august 2, 2021 accepted : september 16, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28370 [7] international energy agency, 2011, system-integrated modular advanced reactor (smart, executive summary on https:// aris.iaea.org/pdf/smart.pdf accessed on july 8, 2021. [8] h.k. kim, s.h. kim, y.j. chung, and h.s. kim, 2013, thermal-hydraulic analysis of smart steam generator tube rupture using tass/smr-s code, annals of nuclear energy, volume 55, page 331 – 340. [9] s. kamalpour, a.a. salehi, h. khalafi, n. mataji-kojouri, and g. jahanfarnia, 2019, impact of integral burnable absorbers on smart reactor behaviour under normal and anomalous operational conditions, progress of nuclear energy, volume 110, page 51 – 63. [10] e. zarfianti et.al., 2017, karakterisasi bahan perisai radiasi neutron ultra high molecular weight polyethene dengan filler gd2o3 menggunakan teknik radiografi neutron, jurnal ilmu fisika, volume 9(1), page 1 – 6. [11] k. okumura, t. kugo, k. kaneko and k. tsuchihashi, 2007, srac2006: a comprehensive neutronics calculation code system, jaea, tokai. [12] k. shibata et.al., 2011, a new library for nuclear science and engineering, journal of nuclear science and technology, volume 48(1), page 1 – 30. 98 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 magnetic susceptibility of ferromagnetic alloy material co(1-x)ni(x) nanocube and nanosphere models imam wahyudi 1 , lutfi rohman 1,a and endhah purwandari 1 1 department of physics, faculty of mathematics and natural sciences, universitas jember, jalan kalimantan no. 37 jember 68121 a el_rahman.fmipa@unej.ac.id abstract. a hard disk is a data storage medium composed of a thin layer of magnetic material. hard drives take advantage of the characteristics of magnetic materials that are stable to heat and have sensitivity to magnetic fields. one of the best materials to use a thin layer ferromagnetic on a hard disk is coni alloy. hard drives with larger storage capacities require magnetic materials with high magnetic susceptibility values and curie temperatures to obtain the best magnetic properties. the magnetic susceptibility of alloy ferromagnetic material co(1x)ni(x) nanocube and nanosphere is calculated using vampire-based micro magnetic simulation. the research was conducted using a literature review on the parameters of the coni alloy material, and then it was simulated in the vampire program. the data generated from the simulation are magnetic susceptibility (1/tesla) and temperature (k). the spectrum of the magnetic susceptibility graph that shifts to the right as the ni (x) composition decreases, it is assumed that the higher curie temperature is produced. otherwise, the increase in ni (x) composition causes the magnetic susceptibility spectrum to shift to the left, with the curie temperature's predicted value getting minor than the other. the nanocube-shaped material has a higher susceptibility value than the nanosphere-shaped material in terms of each ni (x) composition variation at its maximum magnetic susceptibility. keywords: magnetic susceptibility, temperature curie, vampire. introduction the need for diverse magnetic technology is the main reason for improving the quality and quantity of products, especially in data storage media. one of the data storage media used is hdd (hard disk drive). hard disk functions to store data by placing a magnetic field through a thin layer of magnetic material [1]. the characteristics of magnetic materials that are stable to heat have expanded their use as a data storage medium. that is, magnetic materials with good magnetic properties will not lose energy when given a heating effect [2]. ferromagnetic materials have the required criteria to obtain the desired storage quantity. where these materials have a high curie temperature value, strong magnetic properties have a magnetic moment orientation that is almost in the same direction and good magnetic susceptibility values [3]. to reduce the excessive exploration of pure ferromagnetic materials, alloying materials have become an alternative in the development of materials. in addition, alloying technology makes it possible to obtain materials with good magnetic properties, one of which is based on their magnetic susceptibility and curie temperature. 99 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 another study on the magnetic properties of co(1-x)ni(x) nanocube model has observed the curie temperature value by varying the composition of the material in the form of random alloy and double layers. in random alloy with composition co0.2ni0.8, co0.5ni0.5 and co0.8ni0.2 with tc values 800k, 1000k, and 1250k, respectively. in double layer with composition co0.2ni0.8, co0.5ni0.5 and co0.8ni0.2 with tc values of 1200k, 1325k, and 1385k, respectively. variations in the composition of co and ni affect the size of the curie temperature value of co(1-x)ni(x) [4]. in addition, research on magnetic susceptibility was also carried out [5], where the magnetic susceptibility graph showed low magnetic susceptibility values when below the curie temperature. in this research, we have investigated susceptibility magnetic of ferromagnetic alloy material co(1-x)ni(x) in the shape geometry: nanocube and nanosphere models. theoretical background magnetic susceptibility is a basic measure of how magnetic material is. by knowing the value of magnetic susceptibility, the magnetic properties of a material can be known. ferromagnetic materials have a magnetic susceptibility value that is influenced by temperature and is assumed by the curie temperature, when the ferromagnetic material is above the curie temperature it will turn into a paramagnetic material. at room temperature, thermal energy tends to randomize the direction of the domains rather than rectify the magnetic moments. in ferromagnetic materials, it is usually easy to reach a state of saturation, where all the atomic moments are in the same direction. in some cases, the saturation state can occur in low-scale fields (sunaryo and widyawidara, 2010). magnetic susceptibility can be used to determine the curie temperature of a material by reviewing the highest magnetic susceptibility produced as shown in figure 1 (evans and biternas, 2014). figure 1. susceptibility graph, magnetic (χ) against temperature (t in unit k) (source: anwar, 2011) the vampire simulation program is an atomistic simulation for magnetic nanomaterials. the program creates atomistic simulations of magnetic materials that are available openly and designed with ease of use in mind, including an extensive set of input parameters to control the simulation via input files. the vampire simulation program can be used to determine the curie temperature of a material. some of the essential advantages of vampire are that it is based on the finite element method, which is suitable for computing non-cube structures. visualization of 100 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 the output file, which includes magnetization data, can be processed using the pov-ray program (evans et al., 2013). materials and methods to produce magnetic susceptibility values and curie temperatures on ferromagnetic co(1-x)ni(x) alloy materials with nanocube and nanosphere geometric shapes, we need data input of material parameters. the data input refers to existing research results. details of the data coni material parameters used for simulation inputs can be seen in table 1. table 1. parameters of co(1-x)ni(x) materials in micromagnetic simulation material ( ) j (j/link) k (j/atom) co 1.72 6.064 x 10 -21 6.69 x 10 -24 ni 0.606 2.757 x 10 -21 5.47 x 10 -26 co(1-x)ni(x) 4.164 x 10 -21 8.12 x 10 -25 (sumber: evans et al., 2013, broeder, 1992, vivas et al., 2012) figure 2. geometry: a) nanosphere with diameter 10 nm and b) nanocube with side length 10 nm the stages in the research are carried out as shown in figure 3. 101 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 figure 3. research flow chart results and discussion magnetic susceptibility observations were carried out by varying the composition of ni (x) with nanocube and nanosphere geometric shapes. the composition of ni (x) used is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9, in addition, the size of the material is 5 nm. based on the simulation results obtained, a graph is made between temperature and magnetic susceptibility. the analysis was carried out by observing the magnetic susceptibility spectrum with a temperature change, in this case at a temperature of 0k to 2000k. the graph results of magnetic susceptibility to temperature can be seen in figures 4 and 5. 102 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 figure 4. graph of magnetic susceptibility to temperature nanocube model figure 5. graph of magnetic susceptibility to temperature model nanosphere based on figures 4 and 5, the resulting magnetic susceptibility spectrum is influenced by changes in ni (x) composition in each geometric shape of the material. the resulting magnetic susceptibility spectrum will shift to the right in nanocube-shaped materials if the ni (x) composition decreases, with the predicted curie temperature value also increasing. on the other hand, the curie temperature produced is thought to decrease if the composition of the 103 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 ni(x) material increases, so that the resulting curie temperature is also expected to decrease. this phenomenon is cause nickel (ni) has lower magnetic properties than cobalt (co). the magnetic susceptibility spectrum in the form of the nanosphere also shows the same graphic profile as the nanocube-shaped material. furthermore, the magnetic susceptibility analysis was reviewed through the maximum susceptibility value for each variation of ni (x) composition in the form of nanocube and nanosphere. the magnetic susceptibility values of co(1-x)ni(x) materials are listed in table 2. table 2. maximum magnetic susceptibility of co(1-x)ni(x) materials composition of ni(x) magnetic susceptibility (1/tesla) nanocubes nanosphere 0.1 0.01672 0.01149 0.2 0.01173 0.01012 0.3 0.01930 0.00999 0.4 0.01201 0.01068 0.5 0.01533 0.01151 0.6 0.01339 0.01282 0.7 0.01644 0.00923 0.8 0.02174 0.01035 0.9 0.00833 0.01256 after that, a graph of the effect of ni (x) composition on the maximum susceptibility is made, as shown in figure 6. figure 6. graph of maximum magnetic susceptibility to variations in the composition of ni(x) the graph in figure 6 shows the magnetic susceptibility value that varies with each ni (x) composition variation. this phenomenon of the curve on the graph is because it reaches the curie temperature, the state of the domain at each. the ingredients for each composition are 104 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 different. so the energy possessed by the material is also different. however, in all variations of the ni (x) composition, the maximum magnetic susceptibility of the nanocube material tends to be greater than that of the nanosphere-shaped material at the composition of ni (0.1) to ni (0.8). except for the composition of ni (0.9), the maximum magnetic susceptibility in the nanosphere form is more enormous value than in the nanocube form. ferromagnetic materials have magnetic susceptibility values that are affected by temperature. the temperature limit at which the material will experience a phase change from ferromagnetic to paramagnetic is indicated by the curie temperature. the material's magnetic susceptibility shows the highest value. in other words, when a ferromagnetic material has a temperature above the curie temperature, the material will turn into a phase of paramagnetic material. in the paramagnetic phase, the orientation of the magnetic moment will be random, which causes the magnetic susceptibility of the material to decrease until it reaches the lowest value and then becomes constant. this constant state is caused because the material is challenging to magnetize again, where the energy needed to align the spin directions is getting bigger. conclusions based on the micromagnetic simulation carried out, the magnetic susceptibility spectrum of the material is affected by variations in the composition of ni (x). the magnetic susceptibility spectrum will shift to the right when the ni (x) composition decreases, with the expected curie temperature increasing. in addition, the maximum susceptibility of the nanocube-shaped co(1-x)ni(x) material tends to be higher than that of the nanosphere-shaped material. references [1] wahyudi, en 2005. getting to know hard drives closer. dynamic information technology journal. 10(3): 168-177. [2] purnama, budi, ismail and suharyana. 2013. micromagnetic simulation study: dependence of coercive field with intrinsic quantity of magnetic nano-dot with perpendicular anisotropy. journal of physics and its applications.9 (1): 30-33. [3] puri, r. k and vk babbar. 2001. solid state physics and electronics. new delhi: s. chand & company ltd. [4] arifin, samuel. 2016. study of magnetic properties of ferromagnetic co(1-x)ni(x) random alloy and double layer materials in various compositions of co and ni materials. essay. jember: jember state university. [5] witthauer, l. and diterle, m. 2007. the phase transition of the 2d-ising model. summer term. 7(1):1-5. [6] sunaryo and widyawidura, w. 2010. learning methods for magnetic materials and identification of natural sand compounds using basic physics principles. journal of education horizon. 29(1): 67-79. [7] evans, fl and andreas biternas. 2014. vampire user manual: software version 4.0. new york: the university of new york. [8] anwar, nurul. 2011. manufacture of nd2feb permanent magnets through mechanical alloy method. essay. jakarta: syarif hidayatullah state islamic university. 105 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 98-105 eissn : 2747-173x submitted : august 15, 2019 accepted : october 20, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.28539 witthauer, l. and diterle, m. 2007. the phase transition of the 2d-ising model. summer term. 7(1):1-5. 63 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 63-67 eissn : 2747-173x submitted: january 3, 2022 accepted: january 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31479 effect of corrosive liquid lead coolant on the structural stability of iron material sudarmadi1,2,a, sutisna2, bowo eko cahyono2 and widiasih3 1sekolah tinggi dirasat islamiyah imam syafi'i jember, indonesia 2department of physics, faculty of mathematics and natural sciences, universitas jember, indonesia 3physics education, universitas terbuka, tangerang selatan, indonesia amadinnoo@gmail.com abstract. for the design of fast nuclear reactors, usually it uses the lead metal alloys for coolant materials. researches about lead coolants, has been carried out experimentally. however, experimental studies in the nuclear material field, besides being expensive, usually also require high safety. in particular, research on the corrosive properties of liquid lead for structural materials requires serious treatment if carried out experimentally. in this case, the computational method is very helpful to overcome these obstacles. in our research we use the molecular dynamics simulation method to know the effect of temperatures and effect of liquid lead corrosion attack to iron material. we want to know that which one is most crucial that causing the damage of the materials: it is due to temperature or due to liquid lead attack. it has been observed from msd curves of simulation results that the liquid lead can make iron material experiencing most damage if compared with temperature effect the interactions among atoms are described by the lennard-jonnes interaction potential. the simulations were run and supported using moldy and ovito software. keywords: corrosion of molten lead, fast nuclear reactor, molecular dynamics simulation, moldy, msd, ovito. introduction the lead-cooled fast reactor is a nuclear reactor design that uses molten lead or lead-bismuth eutectic material as coolant. the most popular coolant as lead-bismuth eutectic or lbe is a eutectic alloy of lead (44.5%) and bismuth (55.5%). in reactor physics and engineering, liquid metals are alloys with low melting points allowing for reactor coolant to be in liquid state in operating range of temperatures (above and not far from the room temperature) [1]. however, it is known that the liquid lead coolant is still a corrosive media, and without protection mechanism to the corrosion of steels from liquid lead attack then the application of nuclear coolant is not acceptable. oxygen control technology has been developed to form protective oxide layers to increase the corrosion resistance of the steel exposed to liquid lead [2]. in addition to many studies related to corrosion prevention methods, there are also many studies to obtain superior corrosion-resistant new materials from molten lead [3]. it also has been found that the attack of molten lead on structural materials as a steel is qualifiedly related to the solubility of the solid in the lead [4]. although a lot of research is experimental, computational research is often done to get details related to the microscopic state of the material. with computing things that are difficult to do 64 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 63-67 eissn : 2747-173x submitted: january 3, 2022 accepted: january 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31479 experimentally are possible. in this case, molecular dynamics simulation methods and dft (density functional theory) have received intense attention to be used in predicting the thermodynamic properties of nuclear materials such as liquid lead coolant [5-10]. arkundato et al have used molecular dynamics methods to predict the thermodynamic physical properties of the corrosion phenomena of materials in molten lead metal [5-10]. nuris (2019) also has studied the interaction of iron in liquid lead with variation of simulation geometry [11]. imanullah et al have also worked on the molecular dynamics simulation to predict the temperature dependence of liquid lead density [12]. although relatively many computational studies have been carried out, there are still many things that can be analyzed regarding the phenomenon of material corrosion to get a more comprehensive understanding of the symptoms of molten lead corrosion. in goal of the study is, we want to see how liquid lead actually affects materials, especially iron. does iron work very fast when it interacts with molten lead? is this damage purely due to temperature or is it due to interactions with the molten metal? theoretical background classical molecular dynamics (md) simulation is a computer simulation method for analyzing the physical movements of atoms and molecules based on the newton equation of motion. the atoms and molecules are allowed to interact for a fixed period of time based on the certain interatomic potential, giving a view of the dynamic "evolution" of the system. in this research we used the lennard-jones potential to describe the interactions among atoms. 𝑉(𝑟) = 4𝜀 [( 𝜎 𝑟 ) 12 − ( 𝜎 𝑟 ) 6 ] (1) in this study we will see how strong the effect of molten lead on the breakdown of iron occurs. simulation is done by placing iron in molten lead at a certain temperature and simulated by molecular dynamics method based on lennard-jones potential. the level of iron damage can be seen from the msd (mean square displacement) curve of iron atoms dissolved in iron lead. the greater the msd, the greater the damage to the material due to the high solubility of iron. 𝑀𝑆𝐷 ≡ ⟨|𝑥(𝑡) − 𝑥0|⟩ 2 = 1 𝑁 ∑ |𝑥𝑖(𝑡) − 𝑥𝑖(0)| 2𝑁 𝑖=1 (2) in this study, we use the potential parameters to run the simulation those are ɛfe-fe = 0.4007 (ev), σfe-fe = 2.3193 å, ɛpb-pb = 0.1910 (ev), σpb-pb = 3.1888 å and ɛfe-pb = 0.2766 (ev), σfe-pb = 2.7541 å [5]. materials and methods in this study, we simulated the fepb interaction using the moldy program developed by keith refson [13]. the temperature used for the simulations are in the range of 400-1100 k with a temperature increase of 200 k. we prepare the simulation for two goals: 1. simulation of pure iron to know effect of temperatures to structure stability of iron 2. simulation of iron in liquid lead to know effect of liquid lead to iron stability 65 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 63-67 eissn : 2747-173x submitted: january 3, 2022 accepted: january 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31479 the stability of the iron will be seen from msd curve [14]. the lower slope of msd means the lower level of the iron damage. figure 1. scheme of md simulation of iron the number of atoms that simulated are iron 1729 (prepared in bcc crystal) and lead 5577 (prepared as liquid). the bcc iron was prepared by ovito program [15]. results and discussion the simulation results can be described in figure 2 as below. figure 2. the msd curves of fe and fe in pb for several temperatures (400k, 600k, 800k, 1000k,1100k) the msd values were computed by previous above msd formula. the top four msd curves belong to the iron in the molten metal. meanwhile, the bottom 4 curves that appear to clump 66 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 63-67 eissn : 2747-173x submitted: january 3, 2022 accepted: january 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31479 together belong to iron without the influence of molten lead. we can see that temperature does affect the structure of the material. the higher the temperature, the faster the deterioration of the material. however, from figure 2 we can see that the molten lead metal effect greatly exacerbates the iron breakdown shown by the top four msd curves. from figure 2, we can see that the damage caused by temperature does not affect the structural damage of iron very quickly when compared to the damage caused by molten lead metal at various temperatures. figure 3. the structure of iron before and after molten lead metal attack: left (0k), middle (400k) and right (1000k) conclusions from this study it can be concluded that the effect of temperature can cause material damage at high temperatures. but the effect of molten lead will cause far more damage than the effect of temperature. therefore, if liquid lead is used as a coolant in nuclear reactor applications, it is necessary to look for superior materials that are resistant to damage either due to high temperatures or resistant to attack by liquid lead. acknowledgements thanks are due to dr artoto arkundato from the computational physics lab., department of physics at the university of jember, for the initial discussion of this research related to the molecular dynamics simulation methods for simulating corrosion of materials. references [1] https://www.nuclear-power.com/nuclear-engineering/materials-nuclear-engineering/ liquidmetals/lead-and-lead-bismuth-eutectic-reactor-coolant/. [2] jinsuozhang, 2009, a review of steel corrosion by liquid lead and lead–bismuth, corrosion science, volume 51, issue 6, june 2009, pages 1207-1227. https://www.sciencedirect.com/science/article/abs/pii/s0010938x09000936#! 67 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 63-67 eissn : 2747-173x submitted: january 3, 2022 accepted: january 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31479 [3] m. tsirlin, s. lesin & h. branover, 1995, the selective corrosion of type 316 stainless steel in molten lead, journal of materials science letters volume 14, pages 1476-1478 (1995). https://doi.org/10.1007/bf00462218 [4] r.c.asher, d.davies, s.a.beetham., 1977, some observations on the compatibility of structural materials with molten lead, corrosion science, volume 17, issue 7, 1977, pages 545-557 [5] a arkundato, z su’ud, m abdullah, w sutrisno, m celino, 2013, inhibition of iron corrosion in high temperature stagnant liquid lead: a molecular dynamics study, annals of nuclear energy 62, 298-306 [6] a arkundato, z su'ud, m abdullah, w sutrisno, 2013, molecular dynamic simulation on iron corrosion-reduction in high temperature molten lead-bismuth eutectic, turkish journal of physics 37 (1), 132-144 [7] a arkundato, m hasan, a pramutadi, ak rivai, z su’ud, 2020, thermodynamics and structural properties of ti3sic2 in liquid lead coolant, journal of physics: conference series 1493 (1), 012026 [8] a arkundato, f monado, z su’ud, 2019, performance of the fe-ni-cr steel alloy in high temperature molten liquid lead, journal of physics: conference series 1170 (1), 012010 [9] u sa'adah, a arkundato, m hasan, 2020, simulation of iron corrosion in lead-magnesium eutectic (lme) using oxygen inhibitor, jurnal sains materi indonesia 21 (3), 129-134 [10] a triwardani, a arkundato, sutisna, w maulina, e purwandari, 2020, investigation of iron in high temperature molten liquid lead using the lennard-jones potential. aip conference proceedings 2278 (1), 020041 [11] ahmad anwar nuris, modeling of ferrous metal diffusion in liquid lead using molecular dynamics simulation, cerimre, vol 2 no 1 (2019): may https://doi.org/10.19184/cerimre.v2i1.20561 [12] muhammad abdul bashar imanullah, artoto arkundato, endhah purwandari, density of liquid lead as function of temperature and pressure based on the molecular dynamics method, cerimre, vol 1 no 1 (2018): november, https://doi.org/10.19184/cerimre.v1i1.19541 [13] keith refson, 1999, moldy: a portable molecular dynamics simulation programfo rserial and parallel computers, computer physics communications 126 (2000) 310–329 [14] https://tinevez.github.io/msdanalyzer/tutorial/msdtuto_brownian.html [15] https://www.ovito.org/windows-downloads/ https://link.springer.com/article/10.1007/bf00462218?noaccess=true#auth-m_-tsirlin https://link.springer.com/article/10.1007/bf00462218?noaccess=true#auth-s_-lesin https://link.springer.com/article/10.1007/bf00462218?noaccess=true#auth-h_-branover https://link.springer.com/journal/10855 https://doi.org/10.1007/bf00462218 https://www.sciencedirect.com/science/article/abs/pii/s0010938x77800012?via=ihub#! https://www.sciencedirect.com/science/article/abs/pii/s0010938x77800012?via=ihub#! https://www.sciencedirect.com/science/article/abs/pii/s0010938x77800012?via=ihub#! https://www.sciencedirect.com/journal/corrosion-science/vol/17/issue/7 https://doi.org/10.19184/cerimre.v2i1.20561 https://doi.org/10.19184/cerimre.v1i1.19541 https://tinevez.github.io/msdanalyzer/tutorial/msdtuto_brownian.html 102 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 the effect of arrive angle of external magnetic field on the shape of hysterisis curve permalloy ni80fe20 by simulations merinda lestari 1 , widia nursiyanto 2,a , and agung tjahjo nugroho 1 1 department of physics, fmipa, university of jember, jember, indonesia 2 program studi teknik mesin, universitas pancasila, srengseng sawah, jagakarsa, jakarta 12640, indonesia a widianursiyanto@gmail.com abstract. one of the developments of magnetic materials is found in hard disk applications, mram and storage media sensors. storage media sensors that are currently being developed are magnetic sensors. magnetic sensor is a type of sensor that utilizes changes in resistance caused by changes in the magnetic field h or b. one of the suitable magnetic materials to be used as a study material for making magnetic sensors is permalloy ni80fe20. the reading error of the magnetic sensor of the ni80fe20 permalloy material affects the results of the hysteresis curve of the material and requires correction of the angle of incidence of the external magnetic field in order to provide accurate results on the storage media. research on the effect of the angle of incidence of the external magnetic field (h) on the hysteresis curve was carried out on an application based on finite difference oommf. the research was conducted by reviewing the parameter literature of the ni80fe20 permalloy material and then compiling it in a script and simulating it on an application based on finite difference oommf. the data obtained from the simulation are normalized magnetization (m), external magnetic field (h) and coercivity field (hc) which have been influenced by the angle of incidence. the results of the hysteresis curve at a size of 5 nm with a variation of the angle of incidence 0 o are indicated by the value of the external magnetic field (h) of 10000 mt to 10000 mt with a coercive field (hc) of 5000 mt to -5000 mt. the normalized magnetization value (m) is 1 to -1. the variation of the angle of incidence of 30 o produces a coercive field (hc) of -108.3 mt to 108.3 mt and a normalized magnetization of 0.86 to -0.86. the 45 o incident angle variation produces a coercive field (hc) -88.4 mt to 88.4 mt and a normalized magnetization of -0.7 to 0.7. keywords: hysteresis curve, angle of arrival variation, oommf, ni80fe20 introduction magnetic sensors are magnetic memory cells that are used to read data head recording systems on various storage media, one example of which is mram (magnetoresistive random access memory). magnetic sensor design errors in mram which refer to the slope of the material layer affect the reading process and increase the size of the bit cell. this requires angle correction in the provision of an external magnetic field so that the capacity of the data stored in the mram is greater. the appropriate magnetic material used in this case is ni80fe20 permalloy. permalloy materials have many beneficial properties, one of which is that the material can only accept one state of magnetization or a single magnetization. lefter and dimian conducted a study on the correction of the angle of incidence of the external magnetic field in 2012 [1]. the research used permalloy magnetic material and a simulation program based on the finite element nmag method. the angle variations used are 0 o , 30 o , 45 o , 60 o , and 90 o . the results obtained in the form of a hysteresis curve that is decreasing and vortex formation is given an external magnetic field that has been influenced by angle [1]. 103 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 the hysteresis curve is obtained by provides a sufficiently large magnetic field in one direction and then decreases so that it goes to zero and then it is reversed in the opposite direction [2]. hysteresis curve is a curve that shows the relationship between the magnetization (m) that occurs in a material with the magnetic field that causes it or the external magnetic field (h). the hysteresis curve is obtained by providing a sufficiently large magnetic field in one direction and then reducing it to zero and then inverting it in the opposite direction. another way is to map the induced magnetic field b in the ferromagnetic material to the different magnetic field strengths h and fulfill the equation: ( ) (1) where b is the magnetic induction (tesla), h is the applied magnetic field (a/m), m is the magnetization (a/m), and is the permeability of the vacuum. the following is a picture of the hysteresis curve. figure 1. hysteresis curve magnetization (m) and magnetic field (b) will provide information about magnetic parameters that may be needed in the study of a material. these parameters include:  ms is the saturation magnetization (maximum).  mr is the permanent magnetization or residual magnetization.  hs is the magnitude of the magnetic field at saturation.  hc is the magnitude of the magnetic field when it reaches the coercivity. the magnitude of the magnetic field h which is applied continuously makes the magnetization reach a saturation (saturated) state which is known as the ms saturation magnetization state. the magnitude of the magnetic field required to reach the saturation state is known as the saturation field hs. this situation makes all the magnetic moments form a single domain that is in the direction of the application of the h magnetic field. the saturation state when the external magnetic field h is reduced to a state called the nucleation field [3]. the hn nucleation field is defined as the initial field that makes the state of the domain structures no longer parallel to each other [4]. the external magnetic field h is reduced to zero, but the residual magnetization makes the curve not return to its original shape, the residual magnetization is known as mr, remanent magnetization. the magnetic domains do not return to their orientation before being given an external magnetic field h, so the material is partially magnetized. the next process of 104 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 reversing the direction of the h field at m = 0 is called coercivity. the magnetization reversal mechanism in single-domain structured particles is known as stoner-wohlfarth particles. when the sample is magnetized toward saturation, or when the sample is small enough that the magnetization is uniform throughout, the sample may consist of a single magnetic domain. the magnetization process of a single domain under the influence of an external field here is different from usual, where the magnetization reversal occurs by rotation rotation in the critical field without any movement of the domain wall [5]. the stoner-wolfarth model describes the curve magnetization of a single domain particle set with uniaxial anisotropy as a result of the shape of particles or from magnetocrystalline anisotropy. figure 2. stoner wohlfarth of hysteresis curve research methods the hysteresis curve using an external magnetic field that is influenced by the angle of incidence is simulated using the oommf micromagnetic program based on finite difference which is the solution to the landau-lifshitz-gilbert equation. ( ) ( ) ( ) ( ) (2) the type of data in the form of permalloy parameters used in the simulation is in table 1 and the geometry size and angle variation used in table 2. table1. permalloy material parameters [6] keterangan unit magnitude ms (saturated magnetization) (a/m) 860 x 10 3 k (anisotropy constant) (j/m) 5 x 10 3 a (exchange stiffness) (j/m 3) 1.3 x 10 -11 105 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 table 2. side sizes of cube geometry and angle of arrival external field variations side sizes of cube angle of arrival external field variations 5 nm 0 o 30 o 45 o 60 o 90 o permalloy material parameters and external magnetic field (h) which have been influenced by angle are arranged in a script with .mif format then entered in the oommf program. after the simulation process is complete, a file in the form of odt is generated. in the file odt, there are the results of the normalized magnetization of the material (m) and the external field that forms it. the results of magnetization and external fields were then analyzed in the origin program and produced a hysteresis curve. results and discussion in this section, we observe the effect of variations in the angle of incidence of 0 o , 30 o , 45 o , 60 o , 90 o and the geometry of the 5 nm permalloy material in the form of a nanocube with the provision of an external field in the direction of the x-axis and y-axis. the first is the result of the direction of the external field x at an angle variation of 0 o . the range of external fields required for the material to be magnetized 1 is -10000 to 10000 mt. according to widodo [7], related to the hysteresis curve, for the small size of the material ferromagnets do require a large external magnetic field (h) so that the material is capable of being magnetized and demagnetized. this means the size of the material also affects the formation of the coercivity field. for a relatively small size of ferromagnetic material, it does require a large enough external field so that the material is able to be magnetized and demagnetized. the coercive field formed is -5000 to 5000 mt. the simulation with a size of 5 nm uses an external magnetic field value in the range of 10000 mt to -10000 mt or 10 t. the coercive field value is in the -5000 mt to 5000 mt range. this value becomes a reference to determine the effect of angles 30 o , 45 o , and 60 o . figure 3. hysteresis curve 5 nm at x-axis and angle 0 o 106 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 at 30 o angle variation requires an external field of -8660 to 8660 mt. this figure is the result of the effect of the 30 o angle on the x-axis of the field of 10000 mt. the value of the reduced coercivity field is in the range of -108.3 mt to 108.3 mt. the maximum normalized magnetization that the material can achieve is 0.866. figure 4. hysteresis curve 5 nm at x-axis and angle 30 o at 45 o angle variation requires an external field of -7071 to 7071 mt. this figure is the result of the influence of the 45 o angle on the x-axis of the field of 10000 mt. the value of the reduced coercivity field is in the range of -88.4 mt to 88.4 mt. the maximum normalized magnetization that the material can achieve is 0.70. figure 5. hysteresis curve 5 nm at at x-axis and angle 60 o variation of 90 o angle does not form hysteresis curve and coercivity field. this happens because the magnetization process is carried out by providing an external magnetic field (h) in the direction of the easy axis of the material, which is located along the x-axis on the dimensions of the material, while when the angle variation is 90 o , the external magnetic field (h) is applied in the direction of the y-axis so that the external magnetic field (h) only hits the y-axis and there is no magnetization on the x-axis, the magnetization value is zero. the simulation results of the influence of the angle of incidence of the external magnetic field or the external field as a whole obtained based on the formation of the hysteresis curve and the 107 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 coercivity field to the variation of the angle that according to the stoner-wohlfarth model the shape of the hysteresis curve depends on the angle between an external magnetic field (h) with the easy axis of the material (anisotropy) affecting it. at = 0 o the shape of the hysteresis curve will be square and the maximum normalized magnetization will be 1. many factors affect the size of the coercive field value, in [8] it has been proven that the size of the material geometry affects the magnitude of the coercive field, i.e. the smaller size of the geometry of the material, the greater the coercivity field and vice versa if the size of the geometry is larger, the smaller the coercive field produced. likewise in this study, produces a smaller coercivity field than 5 nm size variation. based on the simulation results, the effect of the angle of incidence of the external magnetic field or the external field as a whole obtained based on the formation of a hysteresis curve of the coercive field value to the geometry size is an inversely proportional relationship formed. this relationship is characterized by the greater the angle variation that affects the external magnetic field used, the smaller the coercivity field and hysteresis curve are produced. at 5 nm the angle variation that does not produce a hysteresis curve is 90 o . this happens because the direction of the external magnetic field is towards the yaxis, while at an angle of 90 o the external magnetic field is affected by the y-axis, resulting in a zero-value curve. figure 6. hysteresis curve 5 nm at x-axis and angle 90 o the simulation results on the y-axis external field produce a hysterical curve but it is not as detailed as on the x-axis, because the anisotropy field is directed at the x-axis but the external field also hits the y-axis. so that it can be seen also the influence of the external field on the formation of the y-axis hysteresis curve, see in figure 7, 8 and 9. 108 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 figure 7. hysteresis curve 5 nm at y-axis and angle 0 o (a) (b) figure 8. hysteresis curve 5 nm at y-axis and (a) angle 30 o and (b) angle 45 o (a) (b) figure 9. hysteresis curve 5 nm at y-axis and (a) angle 60 o and (b) angle 90 o 109 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 102-109 eissn : 2747-173x submitted : august 25, 2021 accepted : october 29, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28377 conclusions the conclusion of research that has been done on the influence of angular variation coming on the external magnetic field on the shape of the hysterical curve is that the greater the variation in angle applied the smaller the coercivity field formed. relatively, small ferromagnetic materials require a large external field for the material to be magnetized. acknowledgements thank you dr. lutfi rohman for his help and guidance in conducting this research. thank you to keris kmt for the facilities that have been provided. references [1] c. lefter, and m. dimian, 2012, micromagnetic analysis of magnetization behavior in permalloy nanoparticles for data storage applications, 11th international conference on development and applications systems, romania. [2] a. aharoni, 1998, introduction to the theory of ferromagnetism, oxford: clarendon press. [3] c. behrel, v. neu, l. schultz, and s. fahler, 2013, magnetically and thermally induced switching processes in hard magnets, journal of applied physics, 112(083919), page 1-5. [4] e. h. frei, s. shtrikman, and d. treves, 1957, critical size and necleation field of ideal ferromagnetic particles, phys. rev. 106(3), page 446. [5] d. djuhana, h. g. piao, s. c. yu, s. k. oh, and d. h. kim, 2009, magnetic domain wall collision arround walker breakdown in ferromagnetic nanowires, journal of applied physics, 106(10), 103926. [6] a. indrawati and e. suharyadi, 2014, studi pengaruh shape terhadap pergerseran domain wall magnetik pada lapisan tipis permalloy, jurnal sains materi indonesia, vol 2(1), page 264-267. [7] a. t. widodo, 2013, studi mikromagnetik dinamika struktur domain pada material feromagnetik py, ni, fe, dan co model nanosprehe, tesis, depok: fmipa universitas indonesia. [8] l. rohman, d. djuhana, b. soegijono, and w. nursiyanto, 2013, dynamics micromagnetic simulation of la0.7sr0.3mno3 (lsmo) disk array patterned ferromagnetic, international journal of basic & applied sciences ijbas – ijens, vol. 13(03), page 17-20. 94 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 study of electronic properties of gaas semiconductor using density functional theory fikri abdi putra 1,a , endhah purwandari 1 and bintoro s. nugroho 2 1 department of physics, faculty of mathematics and natural sciences, universitas jember, jalan kalimantan no. 37, jember 68121, indonesia 2 physics department, faculty of mathematics and natural sciences, universitas tanjungpura, jl. prof. dr. h. hadari nawawi, pontianak, indonesia a fikriabdi21@gmail.com abstract. the properties of gaas material in zinc blende type was calculated using hiroshima linear plane wave program based on the density functional theory. this calculation aims to determine electronic properties of gaas material are based on density of states and energy band structure. this simulation’s results are dos shows that hybridization of s orbital of ga with s orbital of as provides covalent properties. the simulation of energy band structure from gaas material indicates that semiconductor properties of gaas is direct band gap. the energy band gap results obtained for gaas is 0.80 ev. the computational result of the energy band gap calculation form hilapw has better accuracy and prediction with good agreement within reasonable acceptable errors when compared to some other dft programs and the results of the experimental obtained. keywords: dft, hilapw, gaas, electronic properties, density of states, energy band structure, energy bandgap introduction the study of materials applied as electronic materials, magnetic materials, spintronic materials, optical materials, etc. has a very important role in the development of science and technology. a widely studied material in this regard is gallium arsenide (gaas). analysis of its characteristics is used for the development of electronics and instrumentation technology. the performance of gaas materials selected to be applied as optical materials for lasers [1], detectors and photovoltaics [2], also as substrate materials [3,4], are influenced by their electronic properties. the electronic properties could be analyzed from the characteristics of the density of state (dos) and energy band diagram, as well as the band gap of the material. the calculation of density of state (dos) and energy band of gaas have been reported by rany and kumar [5] using density functional theory implemented by siesta code, in local density approximation with exchange correlation parameterized by perdew and zunger. the gaas energy band gap, which was simulated using the zincblende structure, was 0.4 ev. experimentally, the measurement of the energy gap was carried out by kusch et al using raman resonance spectroscopy. at room temperature and 0 k, the energy gaps of gaas with a zincblende crystal structure were obtained at 1.425 ev and 1.519 ev, respectively [6]. in this paper, we perform the calculation of band gap of gaas zincblende type based on the band structure using dft method through hilapw program package. it is designed to perform bandstructure calculations based on the density functional theory (dft), with some features including scalar-relativistic spin-polarized calculations within the local (spin) density 95 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 approximation (lsda); all-electron self-consistent calculations; total-energy and atomic-force calculations for determining the equillibrium structure and phonons; electron density-of-states (dos) calculations; and also for 2d or 3d drawing of electron density and potential function calculations [7]. the energy gap of gaas obtained have been compared with other dft methods and also with experiments as validation result. theoretical background gaas is an alloy semiconductor material consisting of gallium (ga) of group iii and arsenide (as) of group v [8]. gaas has a space group f-43m [9] with zinc blende type structure [10] as shown in figure 1. figure 1. the crystal structure of gaas [10,11] this material is classified as a semiconductor, which is widely studied and developed as nano materials products [13] as well as the substrate for other materials [3,4,12]. density functional theory (dft) is a numerical method based on electron density which replaces the electron wave function [14,17] developed with the approach of hohenberg-kohn theory [15] and outlined in the kohn-sham equation [16]. materials and methods this material simulation program uses the dft method of hilapw. hiroshima linear plane wave (hilapw) is non-open-source simulation program developed by prof. tamio oguchi (japan) from the theory group of hiroshima university on the linux operating system using the fortran code. the program is used to calculate density of states (dos) and energy band structure until it reaches a self-consistent state is means a state when electron density at the end of the calculation is close to the input of the previous electron density so that the ground state condition is obtained [17]. the calculation is conducted by iteration process starting with guessing the electron density, which is a function formed by the wave function of electrons. the calculation is continued by calculating the hartree potential and the potential exchangecorrelation to obtain a solution of the calculation in the form of schr ̈dinger equation as [ ( ⃗) ( ⃗) ( ⃗)] ( ⃗) ( ⃗) (1) 96 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 solving equation (1) produces a new wave function that forms the density of new electrons. if the density is equal to or close enough to the initial input density, a self-consistent condition is obtained. if the condition has not been reached, the calculation is repeated with the input density of the newly obtained density value. inputs in the hilapw dft calculation are lattice parameters, space group, atomic position in unit cells, k-point mesh. details of some parameters of gaas structure are listed in table 1. table 1. parameter of gaas material zinc blende structure space group lattice parameters vector k-point mesh ga as f-43m 5.652 ̇ 90 o 5.652 ̇ 90 o 5.652 ̇ 90 o 0 0 0 0.25 0.25 0.25 4 4 4 the electron density simulation uses the job-scf shell-script containing input parameters (sets.in) and scf (law.in) control along with other supporting files. this simulation produces output (wave.out) that is used for dos simulation and energy band structure by converting it into input (wavin). the next step of dos simulation using job-dos contains input (doss.in) and wavin from scf calculation to get tdos.ps and pdos.ps. the file is plotted with psp commands using gnuplot to generate tdos and pdos curve. wavin file from the scf simulation and input (kpts.in) is used for job-ek simulation generate eigen-energy value. this value is used to obtain results in the form of eigen-state. this result is used to plot energy band structure with psp command using gnuplot to obtain energy band structure curve. dos and energy band structure plot results will later be used for the analysis of the results. after the analysis of curve is carried out, a conclusion will be obtained. results and discussion density of state (dos) of gaas the calculation of density of state (dos) in the total density of states (tdos) and partial density of states (pdos) are completed using the job-dos shell script and plotted with gnuplot to obtain tdos and pdos curve. the curve of tdos is analyzed based on the density distribution of the electron states that contribute to gaas material [18], while the curve of pdos is analyzed based on the density of each the orbital states of constituent atomic electrons that contribute to gaas material. 97 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 (a) (b) figure 2. curve of dos on gaas material (a) tdos and (b) pdos the curves of dos consisting of tdos and pdos is shown in figure 2 with the x-axis indicating the energy level in (ev) units and the y-axis indicating the magnitude of the states of tdos and pdos in (states/ev) units. it can be seen in figure 2 (a) that the energies ranging from 0 ev to 16 ev perform the valence band, while the conduction band is mainly distributed between 0 ev and 8 ev. the zero energy indicates the fermi level of gaas. figure 2 (b) exhibit the partial density of state of each element. the solid line defines the s-orbital, as well as the dash line represents the p-orbital. the highest state valence band is possessed by the pdos of as s, ranging from -13 ev to -10 ev. the lowest state of valence bands is entirely from ga d, where the peaks are less noticeable. the upper most group of valence bands is clearly dominated by as p, with a significant overlap with ga s and a smaller contribution from ga p. the conduction band in pdos curve shows that ga and as have overlapping states as evidenced by similar states with the same high energy ranges. based on this, the states that formed in tdos have a widening of states with a high energy range. the conduction band overlap between orbital ga s and orbital as p indicate an hybridization characteristics, where their interactions represent covalent bonds. energy band structure of gaas the curve of the energy band structure is related to the permissible energy range and the not allowed electron wave function [19]. this energy range describes electronic states [20] means that the energy band structure is correlated with dos shown in figure 2, where the states on the tdos curve denote an energy band. the energy band structure is calculated via the jobbs shell script and plotted using gnuplot program to obtain the energy band structure curve shown in figure 3. 98 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 figure 3. curve of the energy band structure of gaas material the curve of the energy band structure of gaas material has a yaxis indicating energy in (ev) and the xaxis indicating k-points of the brillouin zones symmetry points. based on the structure energy band, there is an energy band is flat in valence band. these energy band is poorly dispersed, which results in very low electron states formed from contribution of orbitals d shown in pdos states in figure 2. the energy band of the orbital d or orbital f is an energy band localized to the atomic nucleus so that the resulting band is less dispersed, while the dispersed band of energy in the form of parabolic (curly) is energy band of orbital s and orbital p [21]. based on the energy band structure shows that the maximum valence band and the minimum conduction band are located on the same symmetry point indicates that the bandgap of this material is direct bandgap. comparison of the energy bandgap value of this study with the results of previous simulations and experiment results is performed by table 2. table 2. comparison of the energy bandgap value of this study with the results of previous simulations and experiment results materials energy bandgap (ev) method reference a. computation gaas 0.8 dft (hilapw), zinc blende, lda gaas 0.099 dft (wien2k), zinc blende, lda [22] gaas 0.4 dft (siesta), zinc blende, lda [5] gaas 0.38 dft (fhi-aims), zinc blende, lda [20] b. experiment gaas 1.519 raman measurements, zinc blende nanowires [6] 99 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 the calculation of the energy bandgap using the hilapw program is obtained of 0.8 ev. this amount is greater than other calculation result [5,20,22]. while the energy bandgap value produced from the experiment result by [6] is 1.519 ev and the reference from [19] is 1.52 ev. based on the comparison of these data, it can be concluded that the energy gap calculation using hilapw code packages is more accurate and has a better approach to experimental results than other dft programs. conclusions the calculation of density of states (dos) and energy band structure has been carried on zinc blende type of gaas with the hilapw program of dft method. the results of dos calculations showed an interaction between orbital s ga and orbital p as formed hybridization, so giving covalent characteristic to semiconductor. the results of calculation on the energy band structure indicate the presence of semiconductor properties that match the results of previous experiments and research on gaas material shows that gaas is a direct bandgap semiconductor with an energy bandgap value of 0.80 ev. the hilapw program has computationally demonstrated good accuracy and prediction on the calculation of energy band structure and energy band gap. acknowledgement thanks to prof. tamio oguchi who has provided training on dft computing in the hilapw program at the computational physics laboratory, department of physics, universitas jember on 30 th july – 1 st august 2018 during guest lecture "dft, hilapw and its applications in material research" organized by dr. artoto arkundato (head of computational physics laboratory). references [1] m. sharmin, s. choudhury, n. akhtar, and t. begum, 2012,optical and transport properties of p-type gaas, journal of bangladesh academy of sciences, volume 36, no. 1, page 97–107, doi: 10.3329/jbas.v36i1.10926. [2] p. cells and u. kingsley, 2016, calculation of the electronic properties of gallium arsenide ( gaas ) calculation of the electronic properties of gallium arsenide ( gaas ) semiconductors for photovoltaic cells, volume 5, no. 9, page 99–104. [3] e. c. larkins and j. s. harris, 1995, molecular beam epitaxy of highquality gaas and algaas, in molecular beam epitaxy applications to key materials, r. f. c. farrow, ed. new jersey: noyes publication, page 114–274. doi: https://doi.org/10.1016/b978-081551371-1.50004-4. [4] d. a. jameel et al., 2020, investigation of the effects of gaas substrate orientations on the electrical properties of sulfonated polyaniline based heterostructures, applied surface science, volume 504, page 144315, doi: 10.1016/j.apsusc.2019.144315. [5] a. rani and r. kumar, 2015, structural and electronic properties of gaas and 100 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 gap semiconductors, aip conference proceedings, volume 1661, doi: 10.1063/1.4915369. [6] p. kusch, s. breuer, m. ramsteiner, l. geelhaar, h. riechert, and s. reich, 2012, band gap of wurtzite gaas: a resonant raman study, physical review b condensed matter and materials physics, volume 86, no. 7, page 1–5, doi: 10.1103/physrevb.86.075317. [7] t. oguchi, hilapw project, 2003. http://www.cmp.sanken.osakau.ac.jp/~oguchi/hilapw/index.html (accessed jan. 15, 2020). [8] h. arabi, a. pourghazi, f. ahmadian, and z. nourbakhsh, 2006, first-principles study of structural and electronic properties of different phases of gaas, physica b: condensed matter, volume 373, no. 1, page 16–22, doi: 10.1016/j.physb.2005.10.130. [9] a. mujica, a. rubio, a. muñoz, and r. j. needs, 2003, high-pressure phases of group-iv, iii-v, and ii-vi compounds, reviews of modern physics, volume 75, no. 3, page 863–912, doi: 10.1103/revmodphys.75.863. [10] j. singleton, 2001, band theory and electronic properties of solids band 2 oxford master series in condensed matter physics. page 157–158. [11] s. m. sze, 2002, semiconductor device : physics and technology, 2nd ed. john wiley & sons, inc. [12] j. chawich et al., 2020, deposition and characterization of zno thin films on gaas and pt/gaas substrates, materials chemistry and physics, volume 247, doi: 10.1016/j.matchemphys.2020.122854. [13] l. liu, y. diao, and s. xia, 2019, high-performance gaas nanowire cathode for photon-enhanced thermionic emission solar converters, journal of materials science, volume 54, no. 7, page 5605–5614, doi: 10.1007/s10853-018-03231-8. [14] s. cottenier, 2002, density functional theory and the family of (l)apwmethods: a step-by-step introduction. belgium: instituut voor kernen stralingsfysica, k.u.leuven. [online]. available: http://www.wien2k.at/reg user/textbooks [15] p. hohenberg and w. kohn, 1964, inhomogeneous electron gas, physical review, volume 136, no. 3b, page 864–871, doi: 10.1103/physrev.136.b864. [16] w. kohn and l. j. sham, 1965, self-consistent equations including exchange and correlation effects, physical review, volume 140, no. 4a, page a1133– a1138, doi: 10.1103/physrev.140.a1133. [17] m. m. richard, 2004, electronic structure, basic theory and practical method. cambridge: cambridge university press. [18] m. sach, 1963, solid state theory. new york: mcgraw-hill book company. [19] k. charles, 2004, introduction to solid state physics, 8nd ed. usa: john wiley & 101 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 94-101 eissn : 2747-173x submitted : august 20, 2021 accepted : october 25, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28375 sons, inc. [20] j. a. owolabi, m. y. onimisi, s. g. abdu, and g. o. olowomofe, 2016, determination of band structure of gallium-arsenide and aluminium-arsenide using density functional theory, computational chemistry, volume 04, no. 03, page 73–82, doi: 10.4236/cc.2016.43007. [21] s. mohammad, 2013, first-principles study on dilute magnetic states and half metallicity in chalcopyrite semiconductors, osaka university, doi: 10.18910/34052. [22] n. n. anua, r. ahmed, m. a. saeed, a. shaari, and b. u. haq, 2012, dft investigations of structural and electronic properties of gallium arsenide (gaas), aip conference proceedings, volume 1482, page 64–68, doi: 10.1063/1.4757439. 72 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 effects of intrinsic layer thickness on the short-circuit current density of crystalline silicon-based solar cells imroatus soleha 1 , endhah purwandari 1,a and endang haryati 2 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no. 37 jember 68121 2 department of physics, faculty of mathematics and natural sciences, university of cenderawasih, jalan kampwolker waena jayapura 99351 a endhah.fmipa@unej.ac.id abstract. the amount of short-circuits current density (jsc) shown in the results of the electrical characterization of silicon (c:si)-based solar cell diodes is one of the determinants of device performance. efforts to increase jsc are carried out by adding pure silicon to the diode junction, thereby increasing the magnitude of photoelectron generation in the material. in this paper, the insertion of an intrinsic semiconductor at various thicknesses will be analyzed for its effect on the characteristics of the resulting current-voltage density. by using a 2d simulation based on the finite element method, the solution to the equation of a solar cell semiconductor with a p-i-n junction structure becomes the basis for calculating the resulting electric current density. the thickness variation of the simulated layer i ranges from 1 μm to 15 μm, with a constant thickness of p and n layers of 0.4 m. the simulation results show that the reduced thickness of the intrinsic layer has a significant effect on the decrease in short-circuit current density. keywords: solar cells, silicon crystals, thickness, intrinsic layer, photoelectrons, short circuit current introduction solar energy is one of the energy sources used to supply the energy needs of solar power plants (plts). besides being available for free, the use of solar energy is one of the efforts to reduce human dependence on fossil fuels, namely coal, oil, and natural gas. the public's needs and industries are fulfilled almost 80% of conventional energy [1]. the potential of solar energy can provide a large contribution if it can be utilized optimally by designing an energy converter device that can supply energy needs. therefore we need a semiconductor device converting sunlight directly into electrical energy called solar cells [2]. sunlight is made up of particles known as photons. the conversion process through the photovoltaic mechanism involves photon energy in solar cells. the photon energy that illuminates the solar cell will be absorbed, reflected, or passed by the material. photons with larger bandgap energies can free electrons from their atomic bonds, and release them into free electrons by leaving holes. these electrons are excited into higher energy levels and behave as charge carriers (current) in electrical potential while storing chemical energy temporarily [3]. the process of forming the pair of charge carriers (electron-hole) is better known as a generation. silicon is the basic material for making solar cells which has an energy gap of about 1.11 ev, so it can absorb more of the sun's spectrum than other materials. solar cells with crystalline silicon material can produce a large enough conductivity during the photovoltaic conversion process because they have an orderly arrangement of atoms and good electrical properties [2]. 73 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 solar cell technology has undergone many developments. to increase the efficiency of solar cells, many efforts have been made to expand the absorption capability of the material for a wider range of electromagnetic wave spectrums. for this purpose, the different device geometry and material combinations have many investigated to support the improvement of solar cell performance [4]. the addition of an intrinsic layer in the p-n junction was found to increase the generation of photoelectrons in the material, so that pin junction solar cells have been widely studied. in the p-i-n solar cells, the p-type semiconductor called p-layer is a layer containing holes as the majority charge carrier and electrons as the minority charge carrier. the n-type semiconductor called the n-layer is a layer containing holes as minority charge carriers and electrons as majority charge carriers. while the i-type semiconductor is an intrinsic layer that has the same number of electrons and holes. the photon energy in the i-layer is utilized for the electron excitation process. the i-layer acts as an active layer that determines the generation of charge carriers by photon energy. in this layer, the process of generation (generation) of electron-hole charge carrier pairs and the process of electron-hole recombination occurs. both generation and recombination, are strongly influenced by the thickness of this i-layer. if the ilayer is too thick, more photons are absorbed, making it more efficient for light absorption [5]. the effect of intrinsic thickness on the calculation of the current-voltage density characteristics of p-i-n junction solar cells has been observed numerically by using the finite element method in 1d form [5]. the variation of the thickness of the i-layer used in this study started from 1 µm – 3 µm with multiples of 1 µm. the simulation produces a current-voltage density characteristic curve with an open-circuit voltage (voc) of 0.025 volts. the open-circuit voltage is a very small value for silicon materials. the impurity or dopants function applied to the poisson equation in the simulation does not match the state of each layer. the impurities entered in all three layers are all the same. the charge carriers in the p-layer should be dominated by holes, while the charge carriers in the n-layer are dominated by electrons [6]. based on this background, this paper will present the characteristics of the short-circuit current density of crystalline silicon-based solar cells, which are observed in more detailed variations in the thickness of the intrinsic layer. simulations were carried out using femlab software with geometric structures modeled in 2d. the variation of the thickness of the i-layer carried out is more than 3 m, namely 1 µm 15 µm with multiples of 1 m. this is done because to find out how much the ability of the i-layer to increase the current density is obtained. numerical modeling in this simulation uses the finite element method (meh). the advantage of the finite element method is that it can model semiconductor materials that have irregular geometric shapes. in addition, it can define the distribution of electric fields and charge carriers that are not linear in each part. the parameters used in this simulation are the parameters obtained from the results of existing experiments and simulations. these parameters are applied to the basic semiconductor equations, namely the poisson equation and the continuity equation. the results of this study are the charge carrier distribution profile and the current-voltage density characteristic curve. the simulation of the calculation of the current-voltage density characteristics is calculated based on the distribution profile of the charge carriers, both electrons, and holes. methods the work is begun by setting the geometry in the 2d form of solar cells, which consists of three subdomain areas, namely p-layer, i-layer, and n-layer. the thickness of the p-layer and n-layer 74 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 was 0.4 µm. meanwhile, the thickness of the i-layer varies from 1 µm to 15 µm in multiples of 1 µm. the width of the structure is maintained at 1.5 µm. the next stage after the depiction of the solar cell geometry is the division of the solar cell geometry. the division of the solar cell geometry into small elements (mesh) that are triangular form. the geometry of the p-i-n junction solar cell in the form of 2 dimensions consists of 10 boundaries. number 1 (anode) and 10 (cathode) are referred to as dirichlet boundary, while numbers 2, 3, 4, 5, 6, 7, 8, and 9 are called neuman boundary. the junction area of the p-i layer, the i-n layer (4 and 7), the anode boundary (1), cathode boundary (10), boundaries (2, 3, 8, and 9) are made smaller (tighter) the mesh size so that the results what you get is more accurate. the geometry of the device is shown in figure 1. figure 1.the division of the geometry of the solar cell device with crystalline silicon (c-si) 2d structure the next step after dividing the geometry of the solar cell is to enter the input parameters, the parameters used are under the crystalline silicon (c-si) material. parameters used in simulation activities with the finite element method do not use units. therefore, a scale factor is used so that the values of these parameters are equivalent. the input parameters include distance (x, y, z), electric potential (ѱ), the concentration of charge carriers (n, p, n), diffusion constant of charge carriers (dn, dp), mobility of charge carriers (μn, μp), and the charge carrier density (ρ). the basic semiconductor equations used in this simulation are the poisson equation and the continuity equation. the poisson equation generally describes the phenomenon of changing the electric field in the form of electric potential (ψ) in a device due to the difference in the concentration of charge carriers (ρ). the poisson equation is a very powerful tool for modeling the behavior of electrostatic systems, but unfortunately can only be solved analytically for very simplified models [7]. therefore, the solution of the poisson equation has been conducted by applying numerically by finite element method. equation 1 describes the poisson equation modified in femlab package, where the charge carrier is treated as the total carrier determined by the intrinsic concentration ni, electric potential (ψ) applied, and the impurities concentration [8] 75 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 ψ q (ρ) q (nie ψu nie ψv n) ( ) the continuity equation in semiconductor materials is known as the generation and recombination process. the generation process (g) is the process of forming electron-hole pairs per second per cubic meter. while the recombination process (r) is the process of releasing electron-hole pairs per second per cubic meter. from these two processes, it can be seen the value of the current density of charge carriers for both electrons jn and holes jp, which is defined in the continuity equation as follows [7]: q ⃗⃗ ⃗ n ( ) q ⃗⃗ ⃗ p ( ) each layer in the p-i-n junction structure has an impurity that defines the dominant charge carrier characteristics. the formulas used for the p-layer, n-layer, and i-layer are shown by equations 4-6, respectively. n (n n n nmax e ( x x ch ) ) (4) n (n pmax e ( x ch ) ) (5) n (n n n nmax e ( x x ch ) n pmax e ( x ch ) ) (6) where ch ju √log (n pmax n n) (7) ndn is the donor concentration in the n-type region, ndnmax is the highest donor concentration in the n-type region, napmax is the highest acceptor concentration in the p-type region, ju is the initial layer length (0.4 m) and x1 is the thickness of the geometric layer of solar cells (1.8 m). the process of generation and recombination that occurs in solar cells is mathematically written in the continuity equation. continuity equations for electrons and continuity equations for holes can be shown in equations 8 and 9, respectively. q ⃗ n ni(uv ) p(ue ψ ) n(ve ψ ) (e x e x) (8) q ⃗ p (e x e x) ni(uv ) p(ue ψ ) n(ve ψ ) (9) all parameters supported by the formula are listed in table 1. 76 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 table 1. parameters in this research parameter number electric charge (q) 1.602 x 10 -19 c permittivity of vacum ( 0) 8.85 x 10 -14 f/cm temperature (t) 300 k boltzman constant (k) 1.38 x 10 -23 j/k intrinsic concentration (ni) 1.46 x 10 10 cm -2 donor concentration (ndn) 10 18 /cm acceptor concentration (ndp) 10 18 /cm permittivity of silicon ( r) 11.8 f/cm[9] the flux of photon (f) 10 -17 cm -2 s -1 [10] a factor of transmission (p) ** coefficient of light absorption ( ) 0,023[11] 10 4 mobility of electron (μn) 800 cm 2 /vs[12] mobility of hole (μp) 200 cm 2 /vs[12] diffusivity of electron (dn) 20.7 cm 2 /s diffusivity of hole (dp) 5.17 cm 2 /s lifetime of electron ( n) *** 2.5 x 10 -12 s[13] lifetime of hole ( n) *** 1 x 10 -11 s[13] mesh 0.005 thickness variation (x) (1-15) µm this research will produce a distribution profile of electron-hole charge carriers and a currentvoltage density curve of j-v solar cells based on c-si, with variations in the thickness of the ilayer. the observed charge carrier distribution profile is the concentration distribution of the charge carriers, both electrons and holes. the distribution of concentration on the highest electron charge carriers lies in the n-layer, while the concentration distribution on the highest hole charge carriers lies in the p-layer. the parameters observed in the results of the j-v current-voltage density curve are the open-circuit voltage (voc) and short-circuit current density (jsc). the current density obtained is the total current density, which is the sum of the current density caused by the movement of electrons and the current density caused by the movement of holes. the value of the current density in all circuits is the same, therefore in this simulation only observing the current density at boundary 1. data analysis was carried out on each j-v current-voltage density characteristic curve obtained with variations in the thickness of the ilayer ranging from 1 µm to 15 µm with multiples of µ1 m. if there is a difference in the j-v current-voltage density curve for each variation of the thickness of the i-layer, then the thickness of the i-layer affects the current-voltage density characteristics of the solar cell. the parameter analyzed here is the short circuit current density (jsc) obtained. the greater the short circuit current density generated on the j-v characteristic curve, the better the performance of the solar cell. results and discussion the calculation of the current density is obtained by applying the voltage input that is of vary at 0-0.45 v. the current density in a semiconductor is caused by the movement of charge carriers, both electrons and holes. in solar cells, electrons move from the n-layer to the p-layer (right to left), while holes move from the p-layer to the n-layer (left to right). thus, the two movements of 77 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 charge carriers (electrons and holes) form parallel currents that produce an electric current. in this simulation, boundary 1 has hole current density (jp) as the majority current density and electron current density (jn) as minority current density. so the total current density at the edge of 1 is the sum of the two current densities. figure 2 – 5 perform the j-v characteristic of solar cell device at the thickness of 1 µm, 5 µm, 10 µm and 15 µm, with the thickness of the p-layer and n-layer each remaining equal to 0.4 m. (a) (b) (c) (d) figure 2. current-voltage density (j-v) characteristic curve of solar cells when the thickness of the p-layer and the n-layer are each fixed at 0.4 m with the i-layer thickness of (a) μm, (b) 5 μm, (c) 10 μm and (d) 5 μm the resulting current-voltage density (j-v) characteristic curve shows the relationship between the total electric current density value and the applied voltage variation. this curve corresponds 78 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 to the characteristic curve of the current-voltage density of solar cells in general. the highest current density curve was obtained when the thickness of the i-layer was made of 15 µm, while the lowest value was obtained at a thickness of 1 µm. in this case, the variation of the thickness of the i-layer gives a change in the value of the short circuit current density (jsc), but there is no change in the voc. as shown in figure 2, the increase in the thickness of the i-layer contributes to an increase in the amount of photon energy that can be absorbed by the solar cell. this can be seen from the tendency of increasing jsc value when the thickness of the i-layer is increased from 1 µm to 15 µm. at the i-layer thickness of 1 µm, 5 µm, 10 µm, and 15 µm, the resulting short-circuit current density is 4.216 ma/cm, 16.50 ma/cm, 28.19 ma/cm and 36.50 ma/cm, respectively. the jsc for all intrinsic thickness variations is shown in table 2. the resulting short-circuit current density increases as the thickness of the i-layer increases. table 2. the jsc and voc of simulated result thickness (µm) jsc (ma/cm) voc (v) 1 4.216 0.45 2 7.669 0.45 3 10.760 0.45 4 13.670 0.45 5 16.500 0.45 6 18.900 0.45 7 21.440 0.45 8 24.320 0.45 9 26.700 0.45 10 28.190 0.45 11 28.470 0.45 12 30.510 0.45 13 32.150 0.45 14 34.220 0.45 15 36.500 0.45 the short circuit current density (jsc) performs the increasing number of photocurrents. the increase of the intrinsic layer has successfully increased the number of charge carriers. the use of a higher absorption factor has strengthened the jsc [14]. unlike the jsc characteristics, the open-circuit voltage (voc) obtained in this study is not affected by variations in the thickness of the i-layer. that is, when the thickness of the i-layer is varied from 1 µm to 15 µm, the resulting open-circuit voltage (voc) does not change. the main factor raising the voc should be done by tuning up the number of doping concentrations [14]. the resulting open-circuit voltage is a constant value of 0.45 volts, which can be seen in table 2. in previous studies, the characteristics of the current-voltage density (j-v) of silicon crystalline solar cells have been simulated with the type of p-i-n junction in 1-dimensional form by herawati [5]. the short-circuit current density produced in this study is greater than that of herawati's one. the short-circuit current density when the i-layer thickness is 1 µm in this study was 4.216 ma/cm, while in herawati's result was 0.0526 ma/cm. the open-circuit voltage produced in this study is also greater than that of herawati. the open-circuit voltage in this study was 0.45 volts, 79 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 while in herawati's (2014) study it was 0.025 volts. this is because there are differences in the value of impurities given in the poisson equation. herawati used a constant value of impurity in both p and n layers, without taking into account changes in the impurity value as a function of position/thickness. in this study, the impurity value applied to the p-layer and n-layer is an exponential function (equations 4 and 5). the hole concentration will decrease when applied from the p-layer to the n-layer. the electron concentration will increase when calculated from the p-layer to the n-layer. in addition, the absorption coefficient of incident photons used in this study is greater than in previous studies. therefore, the current density value generated in this study is larger without taking into account changes in the value of impurities as a function of position/thickness. in this study, the impurity value applied to the p-layer and n-layer is an exponential function (equations 4-6). the hole concentration will decrease when applied from the p-layer to the n-layer. the electron concentration will increase when calculated from the player to the n-layer. in addition, the absorption coefficient of incident photons used in this study is greater than in previous studies. the absorption coefficient of the material can describe the number of photons that are absorbed by the material and encourage the creation of free electrons. conclusions based on the simulation results and the discussion that has been carried out, it can be concluded that the variation of the thickness of the i-layer from 1 μm to 15 μm with the thickness of the n-layer and p-layer being kept constant at 0.4 m affects the characteristics of the short circuit current density jsc produced by the solar cell. the thicker the i-layer applied, the higher jsc produced by the solar cell. on the other hand, the thinner the i-layer applied, the lower jsc produced by the solar cell. the highest jsc was obtained when the thickness of the i-layer was made 15 μm, while the lowest value was obtained at a thickness of 1 μm. the variation of the thickness of the i-layer does not affect the open-circuit voltage (voc) generated by the solar cells. references [1] n. a. handayani and d. ariyanti, 2012, potency of solar energy applications in indonesia, international journal of renewable energy development, 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[6] a. ibrahim, 2011, analysis of electrical characteristics of photovoltaic single crystal silicon solar cells at outdoor measurements, smart grid, and renewable energy, vol. 80 computational and experimental research in materials and renewable energy (cerimre) volume 2, issue 2, page 72-80 eissn : 2747-173x submitted : july 20, 2019 accepted : october 3, 2019 online : november 24, 2019 doi : 10.19184/cerimre.v2i2.27373 02, no. 02. [7] a. akinpelu, o. a. akinojo, m. r. usikalu, c. a. onumejor, and t. e. arijaje, 2018, a numerical simulation and modeling of poisson equation for solar cell in 2 dimensions, iop conference series: earth and environmental science, vol. 173, no.1. [8] e. danielsson, 2000, femlab model library for semiconductor devices, stockholm: the royal institute of technology, pp. 344–362. [9] r. s. yuniarsih, e. purwandari, m. misto, e. supriyanto, and s. supriyadi, 2018, built in potential of a-si:h based p-i-n solar cell at different energy gap of intrinsic layer, computational and experimental research in materials and renewable energy, vol. 1, no. 1. [10] e. purwandari and t. winata, 2013, efficiency calculation analysis of a-si:h solar cells for determination of optimum filament temperature in material deposition, jurnal ilmu dasar, vol. 14, no. 1. [11] d. m. jasruddin and a. momang, 2009, development of hydrogenated amorphous silicon solar cell p-i-n in double pecvd reactor, physics application journal, vol. 5, no. 1, pp. 14–21. [12] e. purwandari and t. winata, 2012, optimasi tekanan deposisi dalam simulasi efisiensi sel surya berbasis material a-si:h, gradien, vol. 8, no. 1, pp. 716–721. [13] c. v. sánchez, 2001, thin film nanocrystalline silicon solar cells obtained by hot-wire cvd, pp. 1995–1997. [14] m. s. yoon, y. bo shim, and y. g. han, 2015, influence of the thickness and doping concentration in pand n-type poly-si layers on the efficiency of a solar cell based on a carbon fiber, journal of the optical society of korea, vol. 19, no. 2. 56 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 56-62 eissn : 2747-173x submitted: april 10, 2022 accepted: may 25, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31566 neutron mean free path in the slab reactor core using onedimensional multi-group diffusion equation putri nabila1, mohammad ali shafii1,a, and seni herlina j. tongkukut2 1department of physics, universitas andalas, padang, indonesia 2department of physics, universitas sam ratulangi, manado, indonesia amashafii@sci.unand.ac.id abstract. analysis of the neutron mean free path in the slab reactor core has been carried out using onedimensional multi-group diffusion equation. this study aims to determine the neutron mean free path in the slab reactor core with the neutron diffusion coefficient calculation using macroscopic cross-section data in the nuclear fuel cell level and the neutron flux distribution. the type of reactor used in this research is a fast reactor with nuclear fuel is uranium-plutonium nitride (u-pun). the neutron mean free path is calculated for 70 energy groups of neutrons by dividing the energy groups, namely the fast energy group, the intermediate energy group and the thermal energy group. the results showed that the neutron mean free path value for u-235 and pu-239 fuels were obtained almost the same in all energy groups, namely in the fast energy group ranging from 0.11.10-2 to 0.17.10-2 cm, in the intermediate energy group 0.16.10-2 to 1.78.10-2 cm, and in the thermal energy group 0.4.0-2 to 8.04.10-2 cm. the neutron mean free path value for u-238 fuel is much smaller than that for u-235 and pu-239 fuel, ranging from 0.03.10-2 to 0.36.10-2 cm. these results can be confirmed, because u-238 fuel is a fertile material. keywords: neutron mean free path, diffusion equation, neutron flux, slab reactor core. introduction neutronic analysis is the fundamental part in studying nuclear reactor systems, besides the problems of thermal hydraulics and reactor safety. neutron transport is described as an integrodifferential transport equation with energy, space and time variables [1]. neutron transport is very important to solve because the distribution of neutrons in the reactor core is related to the distribution of reactor power. in order to properly design a nuclear reactor, it is necessary to predict how the neutrons are distributed throughout the system. unfortunately, determining the distribution of neutrons is a difficult problem in general [2]. the ideal neutron flux distribution will be achieved if the neutron flux is perfect, i.e. the average neutron flux is equal to the maximum neutron flux. however, a perfectly neutron flux distribution is difficult to achieve. one way to obtain the ideal neutron flux without increasing the maximum flux is to calculate the neutron mean free path. the neutron mean free path is the distance traveled by a neutron before colliding with a nuclide [3]. the neutron mean free path determines how far the neutron travels before colliding the nucleus and participating in the type of reaction that is formed. in the theory, materials with high absorption have short the neutron mean free path values. in the calculation, the neutron mean free path value is influenced by the value of the macroscopic cross-section, the distribution of the neutron flux and the neutron diffusion coefficient. the calculation of the neutron mean free path value in this study can be compared with theory and find out how neutrons interact with matter. 57 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 56-62 eissn : 2747-173x submitted: april 10, 2022 accepted: may 25, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31566 solving the diffusion equation gives the shape of the distribution of the neutron flux with respect to space and energy. in the diffusion equation, the neutron energy is assumed to have energy groups, so the equation is called the multi-group diffusion equation. shafii et.al. [4] investigated the value of the neutron diffusion coefficient as a function of energy using multi-group diffusion equation with a macroscopic cross-section value as the input. the results show that the value of the diffusion coefficient to the extrapolated distance is only accurate in the fast energy group, and the value of the diffusion coefficient to the energy function is greater in fissile materials than in fertile materials. the macroscopic cross-section data required from this study refers to the results of research from shafii et.al. [5]. according to [5], from the results of the homogenization of nuclear fuel cells in a fast reactor with uranium-plutonium nitride (u-pun) fuel and lead-bismuth (pb-bi) as a coolant, the total macroscopic cross-section for uranium and plutonium nuclides undergoing overlap in the high energy region, giving results that are in accordance with the reference, namely fast neutrons reacting at high energies. in contrast to previous studies, this study determine the neutron mean free path in the reactor core in the form of a one-dimensional slab using the multi-group diffusion equation. the slab reactor core is assumed to be composed of homogeneous nuclear fuel cells. this research is part of the continued neutronic analysis, which is to determine the mean free path of the neutrons in the fuel cell as a function of energy. this research uses a fast reactor type design and uses uranium-plutonium nitride (u-pun) as fuel and lead-bismuth (pb-bi) as coolant. this research begins by calculating the neutron flux at the fuel cell level. the neutron mean free path calculation will complement the neutronic analysis data in the design of nuclear reactors that will be better. this research is in the form of developing a nuclear computing program using delphi programming. theoretical background at steady state and one-dimensional homogeneous medium, the neutron diffusion equation can be written as, −𝐷𝑔∇ 2𝜙𝑔(𝑥) + σ𝑎𝑔𝜙𝑔(𝑥) = 𝑆𝑔(𝑥) (1) where g is an index of neutron energy group, 𝐷𝑔 is neutron diffusion coefficient, 𝜙𝑔 is nutron flux, σ𝑎𝑔 is an absorption macroscopic cross-section and 𝑆𝑔 is neuron source. equation (1) can be simplified to 𝑑2𝜙𝑔(𝑥) 𝑑𝑥2 − σ𝑎𝑔 𝐷𝑔 𝜙𝑔(𝑥) = − 𝑆𝑔(𝑥) 𝐷𝑔 (2) the boundary conditions that apply to equation (2) are 𝜙(𝑥 = 0) = 𝜙(𝑥 = 𝐿) = 0 𝑆(𝑥 = 0) = 𝑆(𝑥 = 𝐿) = 0 (3) (4) equation (2) can be written in discrete form as follows: 58 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 56-62 eissn : 2747-173x submitted: april 10, 2022 accepted: may 25, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31566 𝜙(𝑖+1)𝑔 − 2𝜙𝑖𝑔 + 𝜙(𝑖−1)𝑔 (δ𝑥)2 − σ𝑎𝑔 𝐷𝑔 𝜙𝑖𝑔 = − 𝑆𝑖𝑔 𝐷𝑔 (5) the neutron flux can be obtained from equation (5) using jacobi method 𝜙𝑖𝑔 𝑛𝑒𝑤 = 𝜙(𝑖+1)𝑔 𝑜𝑙𝑑 +𝜙(𝑖−1)𝑔 𝑜𝑙𝑑 (δ𝑥)2 + 𝑆𝑖𝑔 𝐷𝑔 σ𝑎𝑔 𝐷𝑔 + 2 (δ𝑥)2 (6) thus, the diffusion coefficient can be obtained as follows: 𝐷𝑔 = (δ𝑥)2(𝜙𝑖𝑔 𝑛𝑒𝑤σag − sig) 𝜙(𝑖+1)𝑔 𝑜𝑙𝑑 + 𝜙(𝑖−1)𝑔 𝑜𝑙𝑑 − 2𝜙𝑖𝑔 𝑛𝑒𝑤 (7) the neutron mean free path is obtained from the neutron diffusion coefficient according to fick's law 𝐷𝑔 = 1 3 𝜆𝑡𝑟𝑔 (8) so that it is obtained the neutron mean free path 𝜆𝑡𝑟𝑔 as a function of group energy 𝜆𝑡𝑟𝑔 = 3 [ (δ𝑥)2(𝜙𝑖𝑔 𝑛𝑒𝑤 σag − sig) 𝜙(𝑖+1)𝑔 𝑜𝑙𝑑 + 𝜙(𝑖−1)𝑔 𝑜𝑙𝑑 − 2𝜙𝑖𝑔 𝑛𝑒𝑤 ] (9) the equation (9) will be used in computational calculations to obtain the neutron mean free path. materials and methods reactor core design specification figure 1 shows the geometric design of the finite slab reactor core with a distance on the x-axis from 0 to l, which is 20 cm. in this study, the 1d diffusion equation to calculate the neutron flux is only in the x-direction, so that the reactor core height can be neglected. the input values used are the macroscopic cross-sections obtained by [5] and the neutron flux distribution by [6] which are then used to determine the neutron mean free path. 59 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 56-62 eissn : 2747-173x submitted: april 10, 2022 accepted: may 25, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31566 figure 1. design of finite slab reactor core with height h and width l computational procedure to facilitate the computational calculations, this study uses various approaches [4]: 1. the cross section of nuclear fuel elements in each region is constant. 2. the flux at any volume is constant, this assumption is referred to the flat flux approximation. 3. the source in each volume is constant, this assumption is called the flat source approximation. 4. the flat source approach is only appropriate if the external source is in the reactor core. 5. the rates of fission and scattering reactions are set as source terms. 6. the reactor core is in the form of a slab and is assumed to be composed of homogeneous nuclear fuel cells. in the slab reactor core, usually the dominant nuclear fuel is u-235 with the slab width is considered l, but in this study three fuels were used, namely u-235, u-238 and pu-239. furthermore, the computation procedure for calculating the mean free path is carried out as follows: 1. the initial neutron source boundary conditions and the neutron flux are determined. 2. macroscopic cross-section of u-235, u-238 and pu-239 are arranged in a homogeneous region and is taken from a reference [7]. 3. the presence of an external source in the system is determined. 4. neutron diffusion coefficient and neutron flux are taken from the reference [5,6]. 5. spatial variable of the mesh is defined. 6. calculation of the mean free path using equation (9) 7. the procedure was repeated for different neutron energy groups, varying from energy group 1 to 70 for each fuel. results and discussion the neutron mean free path values for u-235 fuel can be seen in figure 2. in the fast energy group, the neutron mean free path values of u-235 range from 0.11.10-2 cm to 0.17.10-2 cm. this happens because u-235 is a fissile material, fissile material in the cross-section pattern of fission reactions decreases in the fast energy group [7]. in the fast energy group, there is no medium 60 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 56-62 eissn : 2747-173x submitted: april 10, 2022 accepted: may 25, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31566 that slows down the motion of the neutrons, so the value of the diffusion coefficient is much smaller [5]. judging from the macroscopic cross-section value, the absorption is small in the fast energy group and the value of the neutron flux distribution is almost uniform in all groups. this condision causes the neutron mean free path value of u-235 to be the smallest in the fast energy group. besides that, the u-235 fuel is also a fissile material that can fission when fired by neutrons in the all energy group. in the intermediate energy group, the neutron mean free path value experienced resonance, i.e. the value is fluctuating in each energy group in a fairly close energy range. this occurs because the interaction of neutrons with matter in the intermediate energy group is unstable. in the thermal energy group, there is more absorption of neutrons in the nucleus, which is called an absorption reaction. the value of the flux distribution in the thermal energy group is also smaller than the value in the other energy groups. this is what causes the neutron mean free path value is largest in the thermal energy group. in this situation, the neutrons interacting with the material u-235 experience accurate collisions with the corresponding neutron mean free path values for each energy group. figure 2. the neutron mean free path of u-235 the neutron mean free path value obtained from the calculation results for pu-239 is a low value in the fast energy group, medium in the intermediate energy group and high in the thermal energy group, as shown in figure 3. pu-239 is a fissile fuel as well as u-235 so the neutron mean free path value is not much different, where the neutrons that interact with the fissile material will undergo a fission reaction process. pu-239 absorbs thermal neutrons to form a compound nucleus which will be excited to a higher energy level than the critical energy. in the thermal energy group of pu-239, more neutron absorption occurs in the nucleus. this is what causes the largest neutron mean free path value in the thermal energy group. 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0 10 20 30 40 50 60 70 80 n e u tr o n m e a n f re e p a th ( cm ) energy group 61 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 56-62 eissn : 2747-173x submitted: april 10, 2022 accepted: may 25, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31566 figure 3. the neutron mean free path of pu-239 the neutron mean free path value of u-238 is much smaller than u-235 and pu-239, which is only in the range of 0.03.10-2 cm to 0.36.10-2 cm. this condition can be understood because u238 is a fertile fuel, where the properties of this material are different from fissile fuels [8]. from the figure 4, it can be seen that the neutron mean free path values is high in the intermediate and the thermal energy group, however in the fast energy group obtained a much smaller value. besides being influenced by the input value of the macroscopic cross-section and the neutron diffusion coefficient, the neutron mean free path value obtained at u-238 is also due to the nature of u-238 which is a fertile material. the interaction of neutrons with fertile material will usually form a reaction that converts the fertile material into fissile material first, so the value is much smaller than the interaction of neutrons with fissile material. figure 4. the neutron mean free path of u-238 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0 20 40 60 80 n e u tr o n m e a n f re e p a th ( cm ) energy group 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0 20 40 60 80 n e u tr o n m e a n f re e p a th ( cm ) energy group 62 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 56-62 eissn : 2747-173x submitted: april 10, 2022 accepted: may 25, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31566 conclusions based on the calculations and analyzes that have been carried out, the neutron mean free path in the slab reactor is influenced by the macroscopic cross-section value, the distribution of the neutron flux and the neutron diffusion coefficient where the neutron mean free path in the fissile material of u-235 and pu-239 is greater than in the fertile material of u-238. the neutron mean free path value is higher in the thermal energy group and smaller in the fast energy group for each fuel due to the effect of neutron interactions on each material. the interaction of neutrons with the nuclide was obtained faster in the fast energy group compared to other, which one the neutron mean free path value did not reach to 1 cm. this is because the reactor design chosen in this study is a fast reactor type. acknowledgements this research is funded by directorate of resources, directorate general of higher education, ministry of education, culture, research and technology, republic of indonesia, according to the research contract number: 021/e4.1/ak.04.pt/2021 and lppm unand number: t/10/un.16.17/pt.01.03/pd-energi/2021. references [1] j. j. duderstadt, and l. j. hamilton, 1976, nuclear reactor analysis, john wiley and sons inc., new york. [2] j. r. lamarsh and a. j. baratta, 2001, introduction to nuclear engineering, third edition, prentice hall, new jersey. [3] t. jevremovic, 2005, nuclear principles in engineering, springer, new york. [4] m. a. shafii, w. w. yunanda, d. fitriyani, and s. pramuditya, 2019, neutron flux distribution calculation for various spatial mesh of finite slab geometry using one-dimensional diffusion equation, aip conf. proc. 2180, 020001-1–020001-6; https://doi.org/10.1063/1.5135510. [5] m. a. shafii, i. zakiya, d. fitriyani, s. h. j. tongkukut, and a. g. abdulah, 2021, characteristics of neutron diffusion coefficient as a function of energy group in the onedimensional multi-group diffusion equation of finite slab reactor core, j. phys.: conf. ser. 1869 012202. [6] w. w. yunanda and m. a. shafii, 2019, analysis of neutron diffusion coefficient as a function of energy in one-dimensional multigroup diffusion equations, jurnal fisika unand, vol 8, no. 4, pp. 363-366. [7] n. aini, and m. a. shafii, 2014, total macroscopic cross-sectional pattern in nuclear fuel cells in fast reactor, jurnal ilmu fisika, vol.6, no.1, pp. 25-29. [8] t. hazama, g. chiba, and k. sugino, 2006, development of a fine and ultra-fine group cell calculation code slarom-uf for fast reactor analyses, j. nucl. sci. technol., vol. 43, no. 8, pp. 908–918. https://doi.org/10.1063/1.5135510 71 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 71-79 eissn : 2747-173x submitted : agustus 15, 2021 accepted : october 2, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28371 the study of the electrical conductivity and activation energy on conductive polymer materials balqyz lovelila hermansyah azari 1,a , totok wicaksono 1 , jihan febryan damayanti 1 , dheananda fyora hermansyah azari 2 1 department of physics, faculty of mathematics and natural sciences, university of jember, jalan kalimantan no. 37, jember 68121, indonesia 2 department of agrotechnology, faculty of agriculture, university of trunojoyo madura, jalan raya telang, kamal, bangkalan, madura 69162, indonesia a azharibalqyz1820@gmail.com abstract. conductive polymers are one of the interesting topics to be developed in recent years. conductive polymers can combine the properties of polymers and the electrical properties of metals. research related to the electrical properties of conductive polymers, including electrical conductivity measurements and determination of activation energy has been carried out. this study aims to determine the effect of addition mass fraction of activated carbon into the nylon polymer on the conductive polymer material based on the electrical conductivity and activation energy. the variations of activated carbon used are 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% (wt/v). the conductive polymer from nylon polymer and activated carbon is made by casting solution method. the electrical conducti vity measurement of the conductive polymer and the activation energy was carried out using the parallel plate method. the value of electrical conductivity increased from 5.62×10 -9 ± 1.89×10 -10 s/cm for the pure nylon to 2.51×10 -8 ± 2.87×10 -10 s/cm for the addition of mass fraction of activated carbon 8% wt/v. meanwhile, there was a decrease in the addition of 9% wt/v and 10% wt/v of mass fraction of activated carbon, which were 2.36×10 -8 ± 3.47×10 -10 s/cm and 2.28×10 -8 ± 4.01×10 -10 s/cm. the activation energy of conductive polymer obtained decreased with increasing in the mass fraction of the activated carbon into the nylon polymer. the activation energy for the pure nylon was 0.0189 ev and 0.0127 ev for the addition of 8% wt/v mass fraction of activated carbon. meanwhile, there was an increase in the addition of 9% wt/v and 10% wt/v mass fractions of activated carbon of 0.0145 ev and 0.0150 ev, respectively. keywords: conductive polymer, nylon, activated carbon, electrical conductivity, activation energy. introduction conductive polymers (cps) have now become one of the interesting topics to be developed on an industrial scale and for commercial purposes. conductive polymers have received a lot of attention because they have similar electrical and electrochemical properties to semiconductors and metals [1]. conductive polymers are an alternative that can be used to overcome the problem of storing electrical energy [2]. conductive polymers have excellent characteristics such as light material weight, low density, corrosion resistance, flexible structure, good conductivity and easy to manufacture so that their production costs are relatively cheaper. conductive polymers have many advantages and can be applied in several ways such as optoelectronic devices, biosensors, rechargeable battery electromagnetic devices and supercapacitors [3]. 72 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 71-79 eissn : 2747-173x submitted : agustus 15, 2021 accepted : october 2, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28371 conductive polymers are a polymer filled with a conductive material such as carbon, metal flakes or fibers and so on. the formation of a conductive polymer by adding a conductive material to the polymer matrix can improve the characteristics of the resulting conductive polymer material in terms of morphology, electrical, thermal, and mechanical properties [4]. several studies related to conductive polymers have been carried out including the study of the electrical conductivity of conductive materials from a mixture of aluminum flakes and nylon polymers [5], the mechanical properties of the functionalization effect of carbon nanotubes from water hyacinth into nylon polymers [6], the effect of addition of carbon nanotubes from water hyacinth into nylon polymers on increasing the value of electrical conductivity and activation energy [7], and synthesized conductive polymer materials from a mixture of nylon and graphene [8]. based on several studies related to conductive polymer materials that have been carried out, nylon polymers with added conductive materials showed better performance than those without added conductive materials. therefore, in this study, a conductive polymer material was synthesized from a mixture of nylon polymer and activated carbon. based on physical, chemical, and structural properties, nylon is a polyamide compound, and it is very possible to be used as a polymer matrix [9]. nylon is a polymer compound that has an amide group on each repeat unit, so nylon is also called a polyamide compound [10]. the choice of nylon raw material as a polymer matrix is due to its relatively low price, good mechanical, thermal and chemical properties [11]. activated carbon is carbon that has been activated chemically, physically or both. this activation process produces a carbon structure with open pores, a larger carbon surface area and a higher adsorption capacity [12]. activated carbon has been widely used as an electrode material because it is considered to have a high specific surface area so that its pore structure can also be utilized, especially to facilitate the formation of an electric double layer on the electrode surface, chemical resistance, good electrical conductivity and affordable price [13]. coconut shell is the best material that can be made into activated carbon because activated carbon made from coconut shell has many micropores, low ash content, high water solubility and high reactivity [14]. measurement of electrical properties is one way to determine the characteristics of a physically conductive polymer material. one of the electrical properties that can be measured from a conductive polymer material is the electrical conductivity and activation energy, where it can be seen that the rate of stability of charge carriers in a material will accelerate with changes in temperature, this can be shown by the smaller the value of the activation energy. electrical conductivity is the ability of a material to conduct electric current as indicated by the measured value [15]. so in this research, electrical conductivity and activation energy were measured on conductive polymer materials from a mixture of nylon and activated carbon. this research is expected to provide information regarding the addition of the right mass fraction of activated carbon into the nylon polymer matrix to obtain the best conductive polymer material measured by the electrical properties. theoretical background electrical conductivity is a measure of the ability of a material to conduct electric current. if there is an electric potential difference at the ends of the conductor, the charges will move to produce an electric current. the value of electrical conductivity is also strongly influenced by the moisture content, density and structure of the material. synthetic and natural materials can be 73 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 71-79 eissn : 2747-173x submitted : agustus 15, 2021 accepted : october 2, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28371 classified into three, namely, conductors, semiconductors, and insulators. the value of the electrical conductivity of the three materials is different [16]. electrical conductivity (σ) is inversely proportional to the value of resistivity (ρ). the value of the electrical conductivity of a material depends on the properties of the material. the equation to calculate the electrical conductivity is [17] : (1) where σ is the electrical conductivity (s/cm), ρ is the electrical resistivity (ω.cm), r is the resistance of the conductive polymer material (ω), l is the thickness of the conductive polymer material (cm), a is the cross-sectional area of the conductive polymer material (cm 2 ). the activation energy (eα) is the energy required to reach the transition state of the complex supplied from outside the system [18]. activation energy can be used as a reference to determine the minimum amount of energy required to activate a reaction as a result of the meeting of molecules in a collision or vibration [19]. the activation energy is influenced by several factors, namely temperature, frequency and catalyst. the relationship between electrical conductivity and activation energy is expressed by the following arrhennius equation: σ = σ0 exp ( ) (2) where is σ0 the initial electrical conductivity, is the activation energy (ev), is the boltzman constant (8.62 x 10 -5 ev/k), and t is the absolute temperature (k) [7]. materials and methods a.) synthesis of activated carbon the coconut shell is cleaned and washed with water, then allowed to dry in the sun. the clean and dry coconut shell is then burned until it becomes charcoal. the charcoal of coconut shell is mashed using a mortar until it becomes powder and sieved using a 200-mesh sieve. the activation process is carried out by soaking coconut shell charcoal into a 5n h2so4 solution for 12 hours to become activated carbon [20]. then the activated carbon is filtered which has been coated with filter paper. the activated carbon was then washed with distilled water until the ph was neutral. then the activated carbon was dried in an oven at 110 °c for 3 hours. the activated carbon from coconut shell is cooled at room temperature to be ready for use. b.) synthesis of conductive polymer materials the conductive polymer material process is made using the casting solution method. the polymer was made by mixing nylon with activated carbon into 20 ml of 25% (v/v) hcl and 2 ml of acetone. the variation of mass variation of activated carbon as much as 1%; 2%; 3%; 4%; 5%; 6%; 7%; 8%; 9%; 10%. then a mixture of nylon and activated carbon was stirred using a magnetic stirrer at a speed of 350 rpm for ± 1 hour. the solution is printed on a glass plate then immersed in distilled water until it forms a solid. the polymer that has been formed is dried for ± 12 hours. 74 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 71-79 eissn : 2747-173x submitted : agustus 15, 2021 accepted : october 2, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28371 c.) the electrical measurement of conductive polymer material in this research, the measurement of the electrical conductivity and activation energy of conductive polymer material use the parallel plate capacitor plate method. parallel plate capacitor is made of pcb plates with a size of 3.1 × 3.1 cm. the electrical conductivity measurements are made by setting up a function generator at a frequency of 1 khz and a digital multimeter is connected to the circuit. the measured voltage value on a digital multimeter is then recorded for each sample tested. meanwhile, the activation energy of the conductive polymer material is obtained from the measurement of the electrical conductivity at various temperatures. the temperature variations used ranged from 25 °c – 100 °c. results and discussion activated carbon is one of the conductive materials that can increase the electrical conductivity. in this study, activated carbon produced from coconut shells has an electrical conductivity value of 2.36×10 -8 ± 5.39×10 -10 s/cm. the value of the electrical conductivity of coconut shell activated carbon resulting from this study lies in the area of the electrical conductivity value of the semiconductor material, which is at a value of 10 -8 s/cm to 10 3 s/cm [21], so that coconut shell activated carbon has the potential to be used as conductive material. in this study, the mass fraction of activated carbon was added to the nylon polymer to obtain the best conductive polymer based on electrical measurements. the synthesis of conductive polymer material in this study uses the casting solution method. the casting solution process is carried out by printing the polymer solution into the desired sheet and put in a fluid medium to remove solvent and precipitate the polymer [22]. electrical conductivity is a measure of the ability of a material to conduct electrical current [17]. the result of the electrical conductivity of conductive polymer materials are shown in table 1. the measurement results show that the addition of the mass fraction of activated carbon into the nylon polymer increases the value of the electrical conductivity of the conductive polymer material. the greater the value of electrical conductivity indicates that the material is better at conducting electricity [15]. based on the research, it was found that nylon polymer without the addition of coconut shell activated carbon mass fraction (0 wt%) had an electrical conductivity value of 5.62×10 -9 ± 1.89×10 -10 s/cm. from the previous research obtained the results of the electrical conductivity of pure nylon of 2.7×10 -9 s/cm [7] and (0.66 ± 0.04) × 10 -9 s/cm [23]. the different results of the electrical conductivity values obtained may be due to the use of nylon raw materials and the polymer fabrication method used. however, the results obtained from measuring the electrical conductivity of nylon polymers are not much different from previous studies. addition of mass fraction of activated carbon to nylon polymer increases the value of electrical conductivity one order compared to pure nylon polymer (without the addition of activated carbon). the electrical conductivity of the conductive polymer material obtained in this study ranged from 9.77×10 -9 ± 3.98×10 -10 s/cm to 2.28×10 -8 ± 4.01×10 -10 s/cm. based on table 1, the addition of the mass fraction of activated carbon in this study increased from the addition of the mass fraction of the conductive polymer sample b (1 wt%) to the conductive polymer sample i (8 wt%), respectively 1.28×10 -8 ± 3.66×10 -10 s/cm, 1.31×10 -8 ± 7.01×10 -10 s/cm, 1.63×10 -8 ± 6.97×10 -10 s/cm, 1.71×10 -8 ± 4.54×10 -10 s/cm, 1.94×10 -8 ± 1.73×10 -10 s/cm, 2.34×10 -8 ± 1.69× 10 -10 s/cm, 2.51×10 -8 ± 2.87×10 -10 s/cm. meanwhile, the value of electrical conductivity 75 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 71-79 eissn : 2747-173x submitted : agustus 15, 2021 accepted : october 2, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28371 decreased with the addition of mass fractions 9 wt% (sample j) and 10 wt% (sample k), which was 2.36×10 -8 ± 3.47×10 -10 s/cm and 2, 28×10 -8 ± 4.01×10 -10 s/cm. table 1. the electrical conductivity of conductive polymer materials at 25 °c conductive polymer sample activated carbon concentration (wt%) electrical conductivity (s/cm) a 0 5.62×10 -9 ± 1.89×10 -10 b 1 9.77×10 -9 ± 3.98×10 -10 c 2 1.28×10 -8 ± 3.66×10 -10 d 3 1.31×10 -8 ± 7.01×10 -10 e 4 1.63×10 -8 ± 6.97×10 -10 f 5 1.71×10 -8 ± 4.54×10 -10 g 6 1.94×10 -8 ± 1.73×10 -10 h 7 2.34×10 -8 ± 1.69×10 -10 i 8 2.51×10 -8 ± 2.87×10 -10 j 9 2.36×10 -8 ± 3.47×10 -10 k 10 2.28×10 -8 ± 4.01×10 -10 the addition of carbon to the nylon polymer improves the structural arrangement of the polymer bonds and facilitates the delocalization of charge carriers resulting in an increase in the electrical conductivity [1]. the greater the value of the electrical conductivity of the conductive polymer material, the better the characteristics of the polymer in conducting electric charges. from the results of this study, it was obtained that the largest electrical conductivity was obtained from the addition of the mass fraction of activated carbon as much as 8 wt% (sample i). figure 1. slope of ln σ to 1/t from conductive polymer material with addition of of mass fraction of activated carbon 8 wt% (sample i) the activation energy of the conductive polymer material has obtained from the slope of the graph of the relationship ln σ to 1/t in the measurement temperature range of 298k – 373k. figure 1 is a graph of the relationship ln σ to 1/t with a temperature range of 298k – 373k on the conductive polymer of sample i. activation energy can be used as a parameter to determine 76 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 71-79 eissn : 2747-173x submitted : agustus 15, 2021 accepted : october 2, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28371 the minimum amount of energy used to activate a reaction as a result of the meeting of molecules in a vibration or collision while the number of collision frequencies between molecules during the reaction can be indicated by the presence of a frequency factor constant, which in this study shows the value of the initial electrical conductivity (σ0) [24]. the value of the initial electrical conductivity (σ0) in this study was obtained from the graph intercept of the relationship ln σ to 1/t. the values of the activation energy in this study are shown in table 2. table 2. the activation energy and the arrhennius equation for conductive polymer materials figure 2. the activation energy of the conductive polymer materials the parameter that has the lowest activation energy is the key [19]. from this study, the lowest activation energy value indicates the best conductive polymer materials. the value of activation energy (ea) can be used to see the characteristics of the charge stability rate mechanism that passes through a conductive polymer material under the influence of temperature. the greater the activation energy means the rate of charge stability that passes through the conductive conductive polymer sample activated carbon concentration (wt%) ea (ev) arhennius eqution of electrical conductivity (s/cm) a 0 0.0189 1.51×10 -7 exp(-0.0353/kbt) b 1 0.0162 1.42×10 -7 exp(-0.0162/kbt) c 2 0.0150 1.34×10 -7 exp(-0.0150/kbt) d 3 0.0144 1.34×10 -7 exp(-0.0144/kbt) e 4 0.0142 1.32×10 -7 exp(-0.0147/kbt) f 5 0.0135 1.30×10 -7 exp(-0.0135/kbt) g 6 0.0130 1.26×10 -7 exp(-0.0130/kbt) h 7 0.0129 1.28×10 -7 exp(-0.0133/kbt) i 8 0.0127 1.20×10 -7 exp(-0.0170/kbt) j 9 0.0145 1.23×10 -7 exp(-0.0163/kbt) k 10 0.0150 1.33×10 -7 exp(-0.0163/kbt) 77 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 71-79 eissn : 2747-173x submitted : agustus 15, 2021 accepted : october 2, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28371 polymer material will be slower with changes in temperature (indicated by the steeper slope of the line). on the other hand, the lower the activation energy, the rate of charge stability passing through the conductive polymer material will be faster with changes in temperature (shown by a gentler slope) [25]. based on the figure 2, it can be seen that the addition of mass fraction of activated carbon to nylon polymer causes a decrease in activation energy compared to nylon polymer without the addition of 0 wt% activated carbon (sample a). the activation energy decreased starting from the addition of the mass fraction of activated carbon, 1 wt% (sample b), 2 wt% (sample c), 3 wt% (sample d), 5 wt% (sample f), 6 wt% (sample g), 7 wt% (sample h) and 8 wt% (sample i), respectively, and increased with the addition of mass fractions of 9 wt% (sample j) and 10 wt% (sample k). the increase in activation energy value with the addition of 9 wt% and 10 wt% activated carbon mass fractions may be due to the uneven dispersion of the mixture between nylon polymer and activated carbon. since good dispersion is essential for forming conductive pathways in conductive polymeric materials, increasing the concentration of activated carbon causes the mixture to become less homogeneous. the addition of more carbon into the nylon matrix reduces the transportability of the polymer chains during the crystallization process and thus increases the activation energy [7]. the activation energy values obtained in this study ranged from 0.0189 ev to 0.0150 ev. the highest activation energy was found in the polymer without the addition of activated carbon (sample a), which was 0.1103 ev. meanwhile, the lowest activation energy was found in the conductive polymer with the addition of 8 wt% activated carbon (sample i), which was 0.0127 ev. the activation energy of the conductive polymer can vary depending on the type of polymer, polymer characteristics (hydrophobicity), and thickness. in this study, the thickness of the conductive polymer material ranged from 0.25 mm to 0.28 mm conclusions the charge carrier stability rate mechanism through the conductive polymer material shows the best results based on the highest electrical conductivity value and the lowest activation energy. in this study, the value of electrical conductivity was obtained when the mass fraction of activated carbon was added as much as 8 wt% (sample i), with a value of (2.51×10 -8 ± 1.69×10 10 ) s/cm. meanwhile, the lowest activation energy was also obtained by adding the mass fraction of activated carbon as much as 8 wt% (sample i) with a value of 0.0127 ev. acknowledgements the author would like to thank the lp2m university of jember for funding the research by hibah keris komputasi material terapan 2021 references [1] l. thanh-hai, k. yukyung, and y. hyeonseok. 2017. electrical and electrochemical properties of conducting polymers. polymers. 9(150): 2-32. 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[25] a. d. anggo, a. s. fahmi, and y. s. darmanto. 2017. energi aktivasi perubahan nilai free fatty acid pada abon ikan lele dumbo (clarias sp) selama penyimpanan. jurnal ilmu pangan dan hasil pertanian. 1(2): 21-28. 30 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 30-37 eissn : 2747-173x submitted: may 15, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31492 future of oil and renewable energy yousof gholipour 1department of engineering, n.i.o.c (national iranian oil company), tehran, iran y.gholipour@yahoo.com abstract. energy is one of the most important elements for every government in the world, and we have seen struggles for energy between some countries or governments and their people. energy is a strategic element for countries especially industrial countries, and oil has been one of the oldest and most important sources of energy in the world, since the 19th century, after coal and other kinds of energy. we want to investigate status of oil as an old energy resource and renewable energy and what will happen in the future for users and producers of it. keywords: renewable energy, oil, petroleum, oil countries, clean energy, environment. introduction the modern history of petroleum started by scottish chemist james young in the 19th century (in 1847 ad). the subject of young patent dated 17 october 1850 was refining of paraffin from crude oil and other production of oils and solid paraffin wax from coal formed. in 1851 young & meldrum and edward william binney completed the first oil refinery in the world [1] it was the start of new energy for those days and we can name that a revolution of energy. the amount of oil energy was significant compared to other sources, and this increased the number of oil fans. on base of definition by u.s. internal revenue service, a boe (barrel of oil equivalent) as equal to 5.8 million btu (5.8×106 btu equals 6.1178632×109 j, about 6.1 gj, or about 1.7 mwh) [2]. after discovering and refining oil changed style of life, and some countries that had oil became rich, some advanced countries became more industrial and other countries became poor. table 1. after the discovery and exploitation of oil oil country advanced country none of them increase revenue increase advancement and welfare increase poverty and needs during this period, competition between countries intensified and every country had tried to get more oil and energy resource till second world war that access to oil as a very important source of energy was (and it still is) a major factor in many military wars, oil facilities as a major strategic asset were widely bombed [3, 4]. gradually oil became more popular and became the first and most important source of energy in the world. 31 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 30-37 eissn : 2747-173x submitted: may 15, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31492 figure 1. oil well masjid soleymaniran in 1908 oil as the main source of global energy at the beginning of the twentieth century, oil became the most important and valuable source of energy in the world, and dependence to it rapidly increased, oil provided lighting, fuel for vehicles, lubricant, industrial usage and etc. now near 90% of vehicular fuel needs are met by petroleum and 40% of all kinds of energy consumption in the united states, and 2% of electricity energy is generated by it. petroleum's worth as a portable, dense energy source and as the base of many industrial chemicals and powering the vast majority of vehicles makes it one of the world's most important commodities. environmental problems in 2018 about a quarter of annual global greenhouse gas emissions was the carbon dioxide from burning petroleum (plus methane leaks from the industry). the largest contributor to the increase in atmospheric co2 is the burning of coal and petroleum combustion [5, 6]. atmospheric co2 has risen over the last 150 years to current levels of over 415 ppm, from the 180–300 ppm of the prior 800 thousand years. on base of satellite measurements that started since 1979 the rise in arctic temperature has reduced the minimum arctic ice pack to 4,320,000 km2, it means a loss of almost half arctic ice packs [7]. ocean acidification is the increase in the acidity of the earth's oceans caused by the uptake of carbon dioxide (co2) from the atmosphere. this increase in acidity inhibits all marine organisms and has a greater impact on smaller organisms as well as crustaceans. 32 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 30-37 eissn : 2747-173x submitted: may 15, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31492 figure 2. changing seawater ph another problem is oil spills, unfortunately the amount of oil spills during accidents varies from a few hundred tons to several hundred thousand tons. oil spills at sea are generally much more damaging than those on land, since they can spread for hundreds of nautical miles in a thin oil slick which can cover beaches with a thin coating of oil [8]. figure 3. environmental problems and beach cleaning after oil spill renewable energy renewable energy is an energy that gains from some resources that they can be renewed free like sunlight, tides, wind, waves, rain and geothermal heat that are naturally and rapidly replenished on a cycle. this type of energy in opposite of fossil fuels, replenished much faster, easier and without pollution [9]. figure 4. wind turbine and solar cell 33 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 30-37 eissn : 2747-173x submitted: may 15, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31492 renewable energy will play the most important and growing role in the future of the world energy system. many countries in the world have renewable energy contributing more than 20% of their energy supply, they are generating over half their electricity from it. there are some countries like iceland and norway that get most of their electricity from renewable energy sources [10]. renewable energy, unlike fossil fuels, which exist only in some countries and is limited, has unlimited resources and can be extracted and accessible everywhere, and the most important feature is, compatibility with the environment [11]. europe's strategy by 2030 is to supply at least 32% of its energy consumption from renewable energy sources. this strategy includes a variety of energy in the field of cooling and heating, transportation and electrical energy. the amount of renewable energy in all eu member states has grown significantly since 2004. according to the latest reports the leading state was sweden (54.6%) with more half of its energy provided by renewable energy in 2018 in terms of gross final energy consumption, and the second is finland (41.2%), and other rankings respectively latvia (40.3%), denmark (36.1%), austria (33.4%). the netherlands has the lowest proportions of renewable energy in 2018 (7.4%), malta (8.0%), luxembourg (9.1%) and belgium (9.4%) [12, 13]. figure 5. global energy sources, renewables are growing rapidly investment in renewable energy since 2004 capacity of renewable energy for many technologies has increased by 10 to 60 percent per year. global investment in renewable energy increased by 5% in 2015 to $ 285.9 billion, breaking the previous record in 2011 by $ 278.5 billion. 2015 was also the first year that renewable energy, with 72 gigawatts of wind and 56 gigawatts of solar photovoltaic, accounted for the majority of all new electricity capacity (134 gigawatts, 54% of total energy) of all renewables. dedicated to themselves, both numbers are record-breaking and have increased sharply compared to 2014 (49 gw and 45 gw, respectively). financially, solar accounts for 56% of total new investment and wind for 38%. 34 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 30-37 eissn : 2747-173x submitted: may 15, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31492 figure 6. status of renewable energy in europe from 2010 to 2019, global investment in renewable energy excluding large hydropower plants amounted to us $ 2.7 trillion, of which china's top $ 818 billion, $ 392.3 billion japan, $ 210.9 billion germany, us share have been $ 183.4 billion, and the united kingdom $ 126.5 billion. this increase was about three or four times the amount of investment in the 2000-2009 decade [14]. according to what we see in figure 4, we must accept the energy revolution, we are at the forefront, and the developed countries will achieve energy independence, and this independence will accelerate their progress. table 2. investment countries in new renewable energy [15] countries investment year 79 182 2008 89 178 2009 98 237 2010 118 279 2011 138 256 2012 144 232 2013 164 270 2014 173 285 2015 176 241 2016 179 279 2017 169 289 2018 35 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 30-37 eissn : 2747-173x submitted: may 15, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31492 countries investment year 172 302 2019 165 304 2020 figure 7. the main source of electricity in the eu what will happen to oil and renewable energy in the future? we want to investigate this section in two parts, one is the oil countries that export oil and receive and spend oil money, and other is some countries that are investing on renewable energy for next generation and energy independency. 1. oil country oil countries traditionally sell their crude oil and spend it on public spending, which is more common in the middle east and africa, but among these countries some have spent more for the welfare of their people and some have resorted to dictatorship and war, some created a better infrastructure, and some are still seeking dictatorship and spending money for war. even these countries on the oil golden era could not join the ranks of the developed world, and by the development of renewable energy we are almost at the end of the oil age and absolute dependence to it. when consumption of fossil fuels reduces (especially oil) oil countries as a producer and exporter have to sell their resources (as one of the most important sources of income) inexpensive and gaining by this method for some of them maybe will not affordable and it's a sadly end if they don't have a plan those days. 2. non-oil country some of non-oil countries are advanced and other are poor and need to help, in oil era, developed countries made optimal use of oil and could to increase their progress by enacting oil laws and taxes but from the other side poor countries have become needed more help, in other word they became poorer than before. following this trend, developed countries will achieve energy independence by increasing investment in renewable energy, and the value of oil as an old energy source will decline. under these circumstances, the oil countries, if they have no alternative for their income, will face huge problems such as the spread of poverty, dissatisfaction and chaos, which may lead to regime change and mass migration to other developed and rich countries. it is an obvious phenomenon that with the increase of poverty, we are witnessing an increase in migration, especially in the elite society. in other words, if the oil countries do not change their plan and 36 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 30-37 eissn : 2747-173x submitted: may 15, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31492 strategy, they will become poor after a cycle of wealth. poor does not only mean lack of money, but also because of the loss of the elite society and the lack of infrastructure and this element intensify poverty to these countries. 3. solution for oil country oil countries need to change their strategies and describe new goals for investing (in parallel with their oil projects) in renewable energy as a clean energy and save environment. it is necessary that they provide some of the energy they need in this way and gradually move towards clean energy. if these countries do not make these reforms, what happened to coal-exporting countries in the 19th century, will happen to them in the 21st century. we are now in a period of changing energy sources. conclusions in this paper we investigated briefly history and usage of oil, and introduced renewable energy and increasing usage and investment in the world on it, and the last step we answered to, "what will happened to oil and renewable energy in the future?" and described what happen in the future and presented a solution to it, especially for oil countries in this limited period of time with noticed to advanced countries targets and warned to them if these countries don't change their strategies, they will get immense damage. another subject as an obvious result of renewable energy usage is reduction of fossil fuels consumption and this change makes reduction of demand and price of oil. acknowledgements i want to acknowledge my friend mrs. mazaherizadeh and anonymous reviewers for their suggestions that helped me to improving the paper. references [1] russell, loris s, 2003, a heritage of light: lamps and lighting in the early canadian home, university of toronto press, isbn 0-8020-3765-8. 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[15] global trends in renewable energy investment 2020, capacity4dev / european commission, frankfurt school-unep collaborating centre for climate & sustainable energy finance, bloombergnef, 2020, archived from the original on 11 may 2021, retrieved 16 february 2021. https://doi.org/10.5194%2fessd-10-2141-2018 https://en.wikipedia.org/wiki/doi_(identifier) https://doi.org/10.5194%2fessd-10-2141-2018 https://en.wikipedia.org/wiki/renewable_and_sustainable_energy_reviews https://en.wikipedia.org/wiki/renewable_and_sustainable_energy_reviews https://en.wikipedia.org/wiki/doi_(identifier) https://doi.org/10.1016%2fj.rser.2014.07.113 https://cleantechnica.com/2021/10/28/some-good-news-10-countries-generate-almost-100-renewable-electricity/ https://cleantechnica.com/2021/10/28/some-good-news-10-countries-generate-almost-100-renewable-electricity/ https://web.archive.org/web/20211117140228/https:/cleantechnica.com/2021/10/28/some-good-news-10-countries-generate-almost-100-renewable-electricity/ https://ec.europa.eu/eurostat/documents/2995521/10335438/8-23012020-ap-en.pdf/292cf2e5-8870-4525-7ad7-188864ba0c29 https://en.wikipedia.org/wiki/eurostat 48 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 interaction between liquid lead and feni material using molecular dynamics simulation feryna ramadhany1, misto1,a, tri mulyono2 and moh hasan3 1department of physics, faculty of mathematics and natural sciences, universitas jember, jl. kalimantan no 37 jember 68121, indonesia 2department of chemistry, faculty of mathematics and natural sciences, universitas jember, jl. kalimantan no 37 jember 68121, indonesia 3department of mathematics, faculty of mathematics and natural sciences, universitas jember, jl. kalimantan no 37 jember 68121, indonesia amisto.fmipa@unej.ac.id abstract. the liquid lead corrosion is often described as a damage of the metal surface due to the high solubility of atoms of the metal that flowing into the liquid metal medium through the diffusion process. this research was conducted to examine the performance of feni alloys in liquid lead at various compositions, especially the metal structure conditions due to interactions between metal atoms at high temperatures. to see the performance of this feni alloy steel, the parameter that you want to know is the diffusion coefficient of its constituent elements. the potential used is the lennard-jones potential. this research uses the lammps molecular dynamics simulation software. from the simulation works can be concluded that the lowest diffusion coefficient of fe in liquid lead which produces the strongest structure is at the composition (concentration) 65% fe and 35% ni with related diffusion coefficient of 5.8582 x 10-12 m2/s, where at this value the corrosion of feni in liquid lead can already be reduced till 77.32%. keywords: liquid lead corrosion, molecular dynamics, feni alloy, composition, lammps introduction in general, the definition of corrosion is the damage that occurs to a material due to a chemical reaction. the presence of a substance that acts as an electrolyte that functions as a conductor of electricity causes the corrosion process to occur [1]. corrosion of liquid metal is a special kind of corrosion called hot corrosion where the phenomenon is that there is no electron transfer (chemical reaction) due to the solubility of solid metals, so sometimes it can only be done by looking at the physical properties of the material such as the diffusion coefficient [2]. the term corrosion for it is often described as damage to the metal surface due to the high solubility of steel/iron atoms into the liquid metal medium through the diffusion process. generally, the basic daily energy needs of a country can be met by using oil, coal and natural gas. however, the availability of conventional energy sources is very limited and over time, the amount will be depleted due to the increasing consumption rate according to the times. the use of nuclear fuel in the process of generating electricity in nuclear reactors is an effective way to produce large amounts of energy that is deemed capable of meeting future energy needs. reactor design that utilizes the concept of nuclear fission reactions is the basis for the development of nuclear reactors that are operated at this time and for many years to come [3]. one of the design of the gen-iv nuclear reactor is a liquid metal cooled fast nuclear reactor (exp. lead) which has mailto:a 49 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 many advantages, one of which is being able to transfer large amounts of heat from the reactor core out to the electric turbine system [4]. however, in addition to the advantages and disadvantages, the fast reactor cooled by liquid lead metal still has drawbacks that must be resolved. one of them is the presence of corrosion in the steel metal material covering the uranium fuel in the nuclear reactor system. at the operating temperature of the reactor (high temperature) this steel material which interacts with the liquid metal coolant (functions to transfer heat from the nuclear reactor fission reaction to the electric turbine) according to experimental data, experiences very high corrosion. the diffusion of atoms of the wrapping steel material into the liquid metal which results in corrosion is caused by the interaction with the liquid metals [5]. one type of future reactor (gen-iv) that uses liquid heavy metals as a coolant and does not use water as a coolant is the fast breeder reactor (fbr). from a chemical and physical point of view, this liquid lead (pb) refrigerant is a very favorable coolant candidate for the design of fast nuclear reactors. the lead (pb) liquid metal coolant does not react actively with water or air so it does not trigger an explosion due to the chemical reaction process. this liquid metal also has high thermal conductivity and heat capacity, making it an efficient heat transfer medium [6]. in general, there are several types of reactor concepts that have been developed, one of which is lfr (lead cooled fast reactor) which is cooled by liquid metal such as lead (pb), lead with bismuth (pb-bi), and also lbe (lead bismuth eutectic). one way to maximize the utilization of energy generated from a reactor is to choose the type of material so that it does not experience unmanageable corrosion. the interaction between liquid lead (pb) coolant with structural materials and fuel cladding at high temperatures which can cause easy corrosion is a common problem that occurs in this type of reactor [3]. nuclear reactor systems can also be designed more optimally in terms of economy and safety by taking into account the selection of cooling materials used. things that must be considered are low melting point values but have high boiling points, heat resistance, corrosion system formation, low swelling ability, high heat transfer and so on [3]. theoretical background diffusion is a slow process in the process of moving atoms in the system, while the phenomenon that occurs due to a potential gradient in the material system is called diffusion transport. the value of the diffusion coefficient increases substantially with increasing temperature, as in chemical reactions. the overall rate of the process is limited when diffusion slows down. there are two things that are distinguished in predicting the diffusion process, namely self-diffusion which is the average displacement of molecules and transport diffusion which is a collection of molecules due to driving forces. to describe the interactions between particles, atoms or molecules using a force field. newton’s second law of motion equations in numerical form are used in molecular dynamics simulations. newton’s second law states that the acceleration of a particle is proportional to the net force on the particle and inversely proportional to its mass, 𝑎𝑖 = 𝐹𝑖 𝑚𝑖 = 𝑑2𝑟𝑖 𝑑𝑡2 (1) where 𝑎𝑖 is the acceleration of particle i, 𝐹𝑖 is the net force acting on the particle, 𝑚𝑖 is the mass of particle i, 𝑟𝑖 is the position of particle i and t is time [7]. 50 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 material system input in the form of material structures either in crystal form or in other forms is versi necessary in dynamic molecular simulations [8]. crystalline structure are very simple solids formed in certain elements, where the atoms occupy the positions of the lattice [9]. computational methods that can be used to predict the static and dynamic properties of a system, which are derived directly from interactions at the atomic or molecular level, are the understanding of molecular dynamics [10]. molecular dynamics is used to predict the physical quantities that you want to know based on the designed model and based on the given input. using the potential function according to the atomic trajectory in solving or finding newton’s equations of motion in this method [2]. the lennard-jones potential to describe metals interaction was used in this study. the experimental data fittings were obtained from the lennard-jones potential parameters consisting of (σ) and (ε) [11]. in general, the lennard-jones potential equation is as follows: 𝑈(𝑟) = 𝑘𝜀 [( 𝜎 𝑟 ) 𝑛 − ( 𝜎 𝑟 ) 𝑚 ] (2) the following table 1 lists the lennard-jones parameters for some of the materials used in this study: table 1 lennard-jones potential parameters (data source from [2]) pair interaction ε (ev) σ (å) fe – fe 0.4007 2.3193 pb – pb 0.1910 3.1888 ni – ni 0.6 1.9 for simulations, we use the lammps molecular dynamics program that contains a set of classical molecular dynamics codes, which can be used to simulate the behavior of up to billions of particles in their solid, liquid and gaseous states. lammps integrates newton’s equations of motion for collections of atoms, molecules and macroscopic particles that interact with initial state or boundary condition forces [12]. to visualize the material system, we use the ovito program. the use of ovito is to visualize 2d and 3d models. ovito is an open-source software that is used as a support in analyzing data from molecular dynamics simulations, such as lammps [13]. materials and methods materials a) iron iron is a metal material needed by the world to build life [14]. pure ferrous metal is soft and malleable, silver in color and looks shiny. iron has an fcc (face centered cubic) structure at high temperatures (> 910°c) and changes back to a bcc (body centered cubic) structure at a temperature of 1390°c. iron has an atomic radius of 126 pm and a melting point of 1535°c [15]. b) lead 51 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 lead is the heaviest metal of all carbon metals, has a blue-gray color with a shiny surface and a soft texture. this lead can usually be found in soil. lead has characteristics, among others, cannot conduct electricity, sound, vibration well and has a melting point at a temperature of 327°c [16]. c) nickel nickel has a melting point of 1455°c with an atomic radius of 124 pm. nickel is resistant to atmospheric corrosion in the passive state at normal temperatures [15]. methods this research begins with creating a simulation system. the simulation system is modeled in the form of a cube measuring 66.20å x 66.20å x 66.20å. the system model used is a simulation system consisting of metal alloys, namely iron (fe) and nickel (ni) placed in liquid lead. the simulation cube contains 5698 atoms of liquid lead with an empty center that will be used as a metal alloy for feni. the metal alloy feni contains 1214 atoms. figure 1. visualization (a) liquid lead (b) feni alloy metal (c) modeling of feni alloys in liquid lead figure 1 shows a visualization of the simulation system model in this study, where liquid lead is shown in red, iron atoms are shown in dark blue, and the alloying element (ni) is shown in yellow. figure 1(a) is liquid lead with an empty middle that will be used as a metal alloy for feni, figure 1(b) is an alloy of iron and nickel, figure 1(c) is a slice of the combined system model between liquid lead and feni alloy. then create an input script for lammps. the simulation input used in this study is an input file that has been prepared and contains several quantities in the form of variables that affect the state of the system such as metal crystal shape, crystal constant, atomic number, atomic weight, potential shape and parameters, number of simulation steps, temperature simulation, simulated pressure, calculated physical quantities. the calculation of the diffusion coefficient (d) is done by calculating the slope value obtained from the gnu plot results. the results of these calculations will be represented in the form of a diffusion coefficient curve that shows the relationship between the concentration (%) of each variation in the composition of the feni metal alloy and the diffusion coefficient. then the analysis of the results and the visualization of the simulation obtained is in the form of an analysis of the structure of ferrous metal with the visualization of the simulation results in the 52 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 form of a crystal structure analysis/cna (common neighbor analysis) used to visualize the data analyzed using the ovito program. the results of running the input file on the lammps generate a data dump file in the form of the xyz position and then enter it in ovito to observe the shape and number of crystal structures that are still left from the results of running simulations through color coding in cna analysis so that based on the visualization, conclusions can be drawn for simulation research that has been carried out done. results and discussion this research is computational research that uses molecular dynamics simulation to predict and study the characteristics of feni alloys in liquid lead with various compositions. simulations were carried out on several variations in the number of nickel atoms combined with iron atoms. simulation data were analyzed by calculating msd, diffusion coefficient and visualization of metal crystal structures. to describe the value of the rate of diffusion indirectly can use the diffusion coefficient, which is directly proportional to the rate of corrosion of iron. in general, the higher the diffusion coefficient, the higher the corrosion rate. conversely, the lower the diffusion coefficient, the lower the corrosion that occurs. the following is table 2 correlation of the concentration of feni alloy composition with the value of the diffusion coefficient from the analysis of the msd plot. table 2. diffusion coefficient values based on variations in concentration of feni alloys in liquid lead no composition concentration (%) d (m2/s) 1 0.5 6.3093 x 10-11 2 5 1.0938 x 10-11 3 10 5.2904 x 10-11 4 15 5.1675 x 10-11 5 20 8.5228 x 10-11 6 25 7.4160 x 10-11 7 35 5.8582 x 10-12 8 40 3.5164 x 10-11 table 2 shows the data for the value of the diffusion coefficient that has been obtained from the msd plot results after performing the simulation. diffusion coefficient data can be used to analyze the corrosion of iron that occurs in liquid lead metal. these data are ferrous metal mixed with nickel (feni in pb). the analysis of the results of the diffusion coefficient will clearly be displayed in the form of a curve as shown in figure 2. 53 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 figure 2. diffusion coefficient of iron in liquid lead figure 2 shows the diffusion coefficient value curve. based on the simulation, variations in feni concentration at a certain percentage will decrease the rate of iron diffusion which indicates a low corrosion rate. the value of the lowest diffusion coefficient is in the range of 5.8582 x 10-12 m2/s – 1.0938 x 10-11 m2/s. feni alloys in liquid lead which have small diffusion coefficient values are at concentrations of 5% and 35%. concentration of 95% fe + 5% ni showed a diffusion coefficient value of 1.0938 x 10-11 m2/s, and concentration of 65% fe + 35% ni showed a diffusion coefficient of 5.8582 x 10-12 m2/s. based on the diffusion coefficient, the calculation of the corrosion rate using msd slope analysis shows that the right composition between fe and ni which produces the most stable material structure (small damage rate) when interacting with metal is at a concentration of 65% fe + 35% ni which is strengthened by analysis of the amount of structure crystals using cna on the ovito program which showed that the crystals were also better at a concentration of 65% fe + 35% ni. this is in accordance with ernik's research (2017), which states that fe-18%ni steel is able to reduce corrosion in liquid lead by lowering the diffusion value of iron and fe-20%ni is able to maintain feni steel structure by reducing the amount of damage to the atomic structure. based on the results obtained, it shows that the differences between ernik's research (2017) and experiments are quite different, due to the difference in the number of atomic interactions and the program used, in previous studies using 3 atoms (fe, ni, and cr) and using the moldy program, while in this research only uses 2 atoms (fe and ni) and uses the lamps program. so it can be said that in this study the best percentage of composition to produce superior material in the form of corrosion-resistant steel is the composition of feni with a concentration of 65% fe + 35% ni. the smaller the value of diffusion, the smaller the level of damage that occurs and produces the most stable material structure when interacting with liquid metal. conclusions based on research on the effect of liquid lead on the structure of feni alloys in various compositions using molecular dynamics methods, it can be concluded that the right composition between fe and ni which can produce the most stable material structure (small damage rate) when interacting with liquid metal is the composition of feni with a concentration of 65% fe + 35% ni. the lowest diffusion was produced at 65% fe + 35% ni which was able to reduce corrosion up to 77.32%. 54 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 acknowledgements the author would like to thank all those who have supported and helped in the writing of this research, primarily to dr. artoto arkundato that allowing the computer facility in computation laboratory to run all simulations, so that this work can be completed until the end. references [1] h. e. ashadi, w. sulistyoweni, i. guniani, 2002, pengaruh unsur-unsur kimia korosi. jurnal korosi. makara teknologi. [2] arkundato, su’ud, abdullah, sutrisno, and cellino, 2013, inhibition of iron corrosion in high temperature stagnant liquid lead, a molecular dynamics study annals of nuclear energy 62 (2013) 298-306, elsevier: netherland. [3] a. fachri, 2017, study awal korosi logam besi dalam logam timbal cair stagnan bersuhu tinggi menggunakan program simulasi dinamika molekul, bandung: itb. [4] dan yurman, 2020, a forecast for the commercial future of gen iv reactors three types have a 50/50 chance of succes, belgium: energy central, https://energycentral.com/c/ec/forecastfuture-gen-iv-reactors-5050-chance-success-three-types . [5] h. sekimoto, 2007, nuclear reactor theory, tokyo: tokyo institute of technology. [6] j. zhang, n. li, 2008, review of the studies on fundamental issues in lbe journal nuclear mater, 373, page 351-377. [7] xiun, liu, s.k. schnell, j. m. simon, p. kruger, d. bideaux, a. bardow, 2013, diffusion coeffisient from molecular dynamic simulation in binary dan termary mixtures, new york: business media new york 2013. [8] k. vainshtein boris, m. vlameder, 2013, structure of crystal, new york: springer science & business media. [9] oxtoby, gillis, and nachtrieb, 2003, prinsip-prinsip kimia modern edisi kelima jilid 2, terjemahan oleh suminar, jakarta: erlangga. [10] h. k. dipojono, 2001, simulasi dinamika molekul, prosiding seminar nasional hamburan neutron dan sinar x ke 4 issn 1410-7686. [11] t. rodgers, 2012, soft matter simulation, manchester: university of manchester. [12] g. s. camprubi, 2011, mechanical properties at nano-lebel, tesis, sweden: lund university. [13] a. stukowski, 2010, visualization and analysis of atomic simulation data with ovito-the open visualization tool, modeling simulation material sci. eng. 18015012. https://energycentral.com/c/ec/forecast-future-gen-iv-reactors-5050-chance-success-three-types https://energycentral.com/c/ec/forecast-future-gen-iv-reactors-5050-chance-success-three-types 55 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 48-55 eissn : 2747-173x submitted: january 27, 2022 accepted: february 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31477 [14] australian geological survey organization, 1999, iron, australia: www.agso.gov.au/education/factsheet/. [15] h. s. kristian & d. s. retno, 2010, kimia anorganik logam, yogyakarta: graha ilmu. [16] m. winter, 1993, iron: the essentials. http://www.webelements.com/iron/. http://www.agso.gov.au/education/factsheet/ http://www.webelements.com/iron/ 38 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 study of the contrast observed on carbon by monte carlo simulation on wet-stem tomography rahmat firman septiyanto1,a and isriyanti affifah2 1department of physics education, universitas sultan ageng tirtayasa, serang, indonesia 2department of chemistry education, universitas sultan ageng tirtayasa, serang, indonesia arahmat_firman99@untirta.ac.id abstract. analyzing the structure of the material in the fields of material science needs a perfect device and methods. due to its principle in projected images at various tilt angles and calculating the threedimensional volume reconstruction with a unique algorithm, tomography has become an excellent tool for analyzing the 3d structure. much research has been studied on applying electron tomography in esem (environmental scanning electron microscopy), which allows observing the wet material (hydrated) in the aquatic environment. in this research, we showed the advisability of wet-carbon compound tomography by simulating the interaction of electron materials. monte carlo simulation was applied in this study to calculate the optimum water layer thickness in the wet material detected. keywords: carbon, electron tomography, simulation of monte carlo, stem. introduction water is a suitable solvent for both organic and inorganic materials. some typical materials could contain water in various concentrations or even be dispersed in the water itself [1]. there are several examples of this phenomenon, such as specimens of living cells (which contain a vast water fraction), biopolymer suspensions (its polymer is water-dispersed), and ceramics (dispersed in a liquid in the process to gain a high density) [2-4]. carbon is involved in biological processes and is contained and or dispersed in water through chemical or physical processes. electron microscopy is an essential technique in understanding the dispersion in suspension and the material's properties at the nanoscale study [5]. the previous study showed that the liquid suspensions could also be learned by using environmental scanning electron microscopy (esem). the pressure in the sample chamber can reach several tens of torr with differential pumping. the function of the peltier phase in esem observes a fully hydrated state object possible [6,7]. changing the pressure of the sample chamber could directly carry out the water condensation and evaporation. the observation of wet material was perfectly shown in esem using backscattering electron detectors or secondary electrons [7]; a collection of sensors placed under a liquid droplet has proven to be an efficient observation mode [8]. tomography plays an essential role in the material characterization of material science and biology cells. its principle is based on the series of projected image acquisitions at different inclination angles and its measurement of the volume of a tomogram (a three-dimensional, 3d, reconstruction) using a unique algorithm [9]. the utility of the combined stem-in-sem and esem had been explained by bogner et al. [8], and this idea became a basic of the wet stem imaging mailto:anailatuss@yahoo.com 39 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 mode development. the previous study has characterized particular materials in several transmission methods and has noticed beam widening through materials width. the result has shown that resolution, directly related to probe size, is subject to a top-down effect [10]. the use of thin materials/ samples thus results in a better resolution, avoiding the probe extending through the thickness of the sample/ material. in the previous study, the minimum water layer determination was analyzed on the mcm-41 sample using wet-stem [11]. the results explain stem configuration on esem as a new approach to characterizing the three-dimensional structure of materials and optimizing the settlement of both resolution levels in several tens of nanometers and large tomogram sizes due to the high transparency thickness. furthermore, by controlling the water pressure of the sample environment and controlling the sample temperature, stem permits the observation of 2d transmission wet samples in esem [11]. the carbon material is easy to get since it is a vastly abundant material. this material has a symbol c with atomic number 6 and has four electrons to construct covalent chemical bonds. carbon has a density of 2.267 g/cm 3 in graphite. in this research, we perform the advisability of wet-carbon compounds tomography by simulating the interaction of electron materials tomography in esem, which permits the acquisition of image sequences on wet materials. the sample used is carbon compounds which are widely used in industry. then, the simulation of monte carlo will be used to estimate the optimum water thickness that can be detected on the wet sample. theoretical background we need to notice the stem tomography technique’s prominent parameters in the monte carlo simulation. tomography-stem technique the tomography-stem electron tomography technique is composed of three significant parts, specifically: (a) a system of tilting, (b) a system to keep the target area within the field of view, and (c) a system of detection [13]. the functions of each part are: (a) the system of tilting is a powerful microscope that permits the introduction of piezoelectric systems for more than 360° rotation around the horizontal axis; rotation was done accurately. (b) systems to keep the desired areas within the field of view a translational piezoelectric systemput the area of interest in the eccentric position before the image series acquisition. then, suitable positioning of this area throughout addition is assured by the motion of the typical microscope phase. (c) a system of detection: a ring-shaped detector is devoted to backscattering for wet stem imaging trim. the collection of electrons is removed from its position and then placed under a thin sample; the electrons are transmitted indirectly (scattered) through the sample. the whole device is controlled and customized by the labview software interface. each series of micrographs was obtained in the mode of stem-in-sem in circular darkfield conditions while the detector was placed under the rotating sample. the 3d structure was reconstructed using traditional software, including tomoj [13]. 40 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 figure 1. schematic of the tomo-stem tool [13] materials and methods we used a hurricane software simulation that can be installed freely on a pc or similar device with a standard specification. carlo decided that this product was free for the public and downloaded it on the official website, so he no longer uses usb hardware. simulation methods, conditions, and parameters the method we used was the electron scattering collection by using hurricane software from samx (http://www.samx.com/index.html.fr) with the simulation of monte carlo. the previous research had also been conducted using the same tool (in both simulation and software) in the detection of mcm-41 material [9,11]. the preliminary phase of the simulation is determining the sample, which can be a pure compound material or a mixture. the material used is carbon, with and without a layer of water, which would be seen through the computation. in addition, we entered the carbon material by using the hurricane software's compound menu, which contains some information on the compound that would be utilized in the simulation. we employed a 30 kev accelerating voltage as specified in the experiment for the computation. the option to set the maximum number of passes achieved during the simulation is one of the simulation parameters. for the simulation, we chose 100,000 passes because the bigger the value of passes, the slower the computation will be. the computation sample structure fits the criteria: x = 5 x 103 nm, y = 5 x 103 nm, and z-axis thickness variations range from 2 x 102 nm to 4 x 103 nm. the mode of the batch simulation model was created to permit several simulations to be run concurrently and consecutively, with or without variations in deposit width. this is especially handy when one of the simulation parameters needs to be changed during the simulation. this study's simulation employed a spherical liquid precipitate with 1000 nm radius and width variations of the liquid layer at 10 nm, 20 nm, 30 nm, 50 nm, and 100 nm. the contrast variation was adjusted to 5% to establish the best water film thickness. the stages of the flowchart in this research are as follows. http://www.samx.com/index.html.fr 41 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 figure 2. flowchart monte carlo simulation stages results and discussion determination of optimum water layer thickness with a variety of sample thicknesses carbon. here we show the results of the monte carlo simulation on a computational box containing carbon thin films of varying thickness. they were coated with water with variations in thickness as well. electrons collected in the monte carlo simulation with water layer thickness variations in the carbon sample can be seen in figure 3. the number of electrons used is 100,000, and the average number of electrons collected at a predetermined scattering angle is between 14° 40° [9]. 42 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 figure 3. the average number of electrons collected at scattering angles between 14° 40° on carbon material with variations in the thickness of the water layer. figure 3 presents the optimum detectable water layer and shows that carbon with a thickness of 500 nm has a maximum point of the number of electrons collected. this represents that the greater the number of scattering electrons entering the dark circular field, the smaller the number of electrons collected at thicknesses above 500 nm. this can happen because the higher the thickness of carbon, the smaller electrons are captured since there are many electrons reflected out of the dark circular field. if we maximize the thickness of carbon from 0 to 500 nanometers, the difference for each thickness of water will be known respectively. all of the thicknesses carbon with water layers, the number of electrons relatively elevate between the thickness of water 200 nm and 500 nm. from here, we can determine the optimal thickness of the water. previous studies with different samples (mcm-41) stated that the curves for different thicknesses of water layers all had the same overall shape, with a maximum thickness of mcm-41 (equal to 2 m) [9]. for the thickness of mcm-41, which is thinner than 1 m, the number of electrons increases as the increase in sample thickness causes an increase in the number of scattering events and scattering angles. on the other hand, for mcm-41, which is thicker than 2 m, an increase in the number of scattering events still leads to an increase in scattering angle, exceeding the maximum gathering angle [9,11]. 43 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 in the case of carbon, the number of electrons collected escalates until the thickness of 500 nm, and the scattering angle elevates as the electron scattering increases. for sample thicknesses above 500 nm, the collection angle will be more than 40°, so it will induce a decrease in electron collection. the number of electrons leaving the sample is slightly affected by the layer of water above it. nothing else affects the number of electrons collected by the detector. therefore, the monte carlo simulation is likely to calculate the optimal water layer in which electrons can be detected at any material thickness. contrast variation water condenses on the sample as the partial pressure of water rises, resulting in contrast fluctuations. figure 4 depicts the projected difference in contrast between dry and wet circumstances. this information relates to the possibility of detecting a water coating on carbon. to get the preferable water width, we set the contrast variation to be larger than five percent (>= 5%) [9] [11]. figure 4 shows how we can identify the best water layer to detect by taking the width of carbon with a contrast fluctuation greater than 5% or equal, and the results are shown in figure 4. the optimal contrast variation has been set at 5%, and the rising thickness of carbon indicates the transition from dry to wet circumstances. for each thickness of carbon, a 5% variation, in contrast, is noted. the ideal water thickness was calculated using the contrast variation for each sample thickness. figure 4. expected dry to wet contrast variation conditions, in a function of carbon’s matrix thickness the monte carlo simulation calculates contrast variation, which explains how a specific area may be separated from the water layer. the formula is as follows: 44 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 𝐶𝑜𝑛𝑡𝑟𝑎𝑠𝑡 𝑉𝑎𝑟𝑖𝑎𝑡𝑖𝑜𝑛 = 𝑁𝑑𝑟𝑦 − 𝑁𝑤𝑒𝑡 𝑁𝑑𝑟𝑦 𝑥100% (1) where n dry and n wet correspond to the number of collected electrons in the desired area with no water layer and a pure water layer of the same thickness [14]. at a certain thickness of a material, the thicker the material, the greater the optimum thickness of the water obtained. the number of electron scattering caught is more significant so that the contrast of the image obtained is more evident. figure 5. contrast variation in carbon in the optimum water layer (electron collected) on carbon with thicknesses of 400 nm, 500 nm, and 700 nm, the best water layer thicknesses that may be detected are 50 nm, 30 nm, and 20 nm, respectively. surprisingly, the ideal water and carbon sample thickness have a linear relationship (figure 5). three of the five water resistance data are taken in figure 5, and the three data taken are perfect linearity data. the link between the ideal value of water and the thickness of carbon is also shown in figure 5, suggesting that the higher the thickness of carbon, the higher the optimum number of water required. this means that the more carbon and water between them, the more electrons water can collect. monte carlo electron trajectory simulation of the interaction volume we may calculate the dimensions of the volume interaction of simple material, such as carbon, using the kanaya-okayama formula stated in equation (1). simultaneously, monte carlo simulations of " bulk materials " produce electron trajectories, with the interaction volume as the limiting factor (as shown in figure 5 for the carbon example). with a computational box sample structure, we have several material thickness parameters: x = 33 x 103 nm, y = 33 x 103 nm, and z = 20 x 103 nm. the dimensions of the interaction volume are calculated using this parameter. 45 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 the dimension of volume interaction on carbon compounds determined from the simulation was found to be eight (8) microns, which is consistent with the kanaya-okayama formula (9 microns). this confirms how we derive the volume interaction boundaries from monte carlo findings. still, it also allows us to specify the volume interaction dimensions of all materials under consideration. moreover, the size of the volume interaction is a major function of the incident beam's energy as well as the chemical's structure and density. kanaya okayama's formula is as follows: r = (0.0276ae 1.67 ) / z 0.89 (2) where r : the dimension of interaction volume a : relative atomic mass (g/mol) z : atomic number ρ : density (g/cm2) e : energy of incident light (kev) figure 6 depicts the electron paths utilized in the monte carlo simulation to determine the volume interaction or the depth dimensions the electrons can travel. the electrons will be scattered, indicated by electron trails when the incident ray is shot; this monte carlo simulation demonstrates the existence of electron traces fired by incoming light with an energy of 30 kv. figure 6. monte carlo electron trajectory simulation of the interaction volume in carbon as a function of the incident radiant energy of 30 kev with a sample thickness of 20,000 nm. conclusions the experimental arrangement was simulated using simulations in stem-in-sem images. the pathways of 100,000 electrons were calculated using unique software, the monte-carlo approach (hurricane program). this simulation allowed us to compute the optimum water layer thickness detected in carbon material. although the relationship is thought to be linear between the ideal water film and sample thickness, the equation is 46 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 dependent on the sample's chemical structure and density. the empirical relationship between the optimum water layer thickness and the sample layer includes measuring the density and interaction volume. it will be fascinating to test the validity of the empirical findings in future work. references [1] j. xiao, g. foray, and k. masenelli-varlot, 2018, analysis of liquid suspensions using scanning electron microscopy in transmission: estimation of the water film thickness using monte–carlo simulations, j. microsc., vol. 269, no. 2, pp. 151–160, doi: 10.1111/jmi.12619. [2] g. foray, s. cardinal, a. malchere, and j. m. pelletier, 2012, mechanical spectroscopy, a tool to characterize cement latex composites, solid state phenom., vol. 184, pp. 399–404, doi: 10.4028/www.scientific.net/ssp.184.399. [3] p. yu, b. cui, and q. shi, 2008, preparation and characterization of batio3 powders and ceramics by sol-gel process using oleic acid as surfactant, mater. sci. eng. a, vol. 473, no. 1–2, pp. 34–41, doi: 10.1016/j.msea.2007.03.051. [4] g. spina, g. bonnefont, p. palmero, g. fantozzi, j. chevalier, and l. montanaro, 2012, transparent yag obtained by spark plasma sintering of co-precipitated powder. influence of dispersion route and sintering parameters on optical and microstructural characteristics, j. eur. ceram. soc., vol. 32, no. 11, pp. 2957–2964, doi: 10.1016/j.jeurceramsoc.2012.02.052. [5] h. stahlberg and t. walz, 2008, molecular electron microscopy: state of the art and current challenges, acs chem. biol., vol. 3, no. 5, pp. 268–281, doi: 10.1021/cb800037d. [6] a. m. donald, 2003, the use of environmental scanning electron microscopy for imaging wet and insulating materials, nat. mater., vol. 2, no. 8, pp. 511–516, doi: 10.1038/nmat898. [7] d. j. stokes, b. l. thiel, and a. m. donald, 1998, direct observation of water-oil emulsion systems in the liquid state by environmental scanning electron microscopy, langmuir, vol. 14, no. 16, pp. 4402–4408, doi: 10.1021/la980281c. [8] a. bogner, g. thollet, d. basset, p. h. jouneau, and c. gauthier, 2005, wet stem: a new development in environmental sem for imaging nano-objects included in a liquid phase, ultramicroscopy, vol. 104, no. 3–4, pp. 290–301, doi: 10.1016/j.ultramic.2005.05.005. [9] k. masenelli-varlot et al., 2014, wet-stem tomography: principles, potentialities and limitations, microsc. microanal., vol. 20, no. 2, pp. 366–375, doi: 10.1017/s1431927614000105. [10] l. reimer, 1974, transmission electron microscopy of thick amorphous, vol. 100, no. june 1973, pp. 81–92. [11] r. f. septiyanto, k. masenelli-varlot, and f. iskandar, 2014, simulation of electron-matter interaction during wet-stem electron tomography, aip conf. proc., vol. 1586, no. november 2015, pp. 82–85, doi: 10.1063/1.4866735. 47 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 38-47 eissn : 2747-173x submitted: may 8, 2022 accepted: may 18, 2022 online: may 31, 2022 doi : 10.19184/cerimre.v5i1.31476 [12] s. banerjee, s. dubey, r. k. gautam, m. c. chattopadhyaya, and y. c. sharma, 2019, adsorption characteristics of alumina nanoparticles for the removal of hazardous dye, orange g from aqueous solutions, arab. j. chem., vol. 12, no. 8, pp. 5339–5354, doi: 10.1016/j.arabjc.2016.12.016. [13] p. jornsanoh, g. thollet, j. ferreira, k. masenelli-varlot, c. gauthier, and a. bogner, 2011, electron tomography combining esem and stem: a new 3d imaging technique, ultramicroscopy, vol. 111, no. 8, pp. 1247–1254, doi: 10.1016/j.ultramic.2011.01.041. [14] j. xiao, l. roiban, g. foray, and k. masenelli-varlot, 2018, characterization of liquid suspensions in 3d using environmental scanning electron microscopy in transmission, microsc. microanal., vol. 24, no. s1, pp. 350–351, doi: 10.1017/s1431927618002246. 68 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 energy yield of the carbonized plant leaf, petiole and branch biomass briquettes for sustainable production of future fuels arry y nurhayati, ach. zulfi n naufal and yuda c hariadia lab of biophysics, physics department, faculty of mathematics and natural sciences, university of jember, jember 68121 indonesia ayuda_ch.fmipa@ unej.ac.id abstract. the effective use of waste biomass is an important factor for sustainability and global energy consciousness. unsurprisingly, tree wastes such as leaves, petiole and branch are plentiful during trimming or autumn season which offer an economical source of biomass. the objective of this study was to probe the mechanical and thermal characteristics of briquettes created from tree waste of langsat, guava and rambutan tree. collected tree wastes (leaves, petiole and branches) were chopped, mixed and then carbonized at 400-600 °c using a charcoal retort tube system. the briquettes were molded manually using a hydraulically briquetting machine at pressures of 20 and 50 n/cm2 for half an hour to 3 hours with regards on the type, density and fragments of the tree. two system and machine were designed and fabricated by biophysics lab, dept. of physics, faculty of mathematics and natural sciences, universitas jember. results indicated that briquettes made from tree waste of langsat, guava and rambutan have signs of mechanical and thermal properties which can be used as briquettes for various industrial uses. keywords: sustainability, alternate fuel, tree waste, biomass, briquette introduction biomass briquette market share has grown 12% to 15% as more worldwide goverments and environment agencies focus towards replacing fossil fuel in concomitance to the rising demand to reduce fossil fuel usage [1,2]. the issue of global warming and renewable energy source has also alleviate biomass briquette role [3] especially carbonized briquette. in indonesia, carbonized briquette has also found significant use as fossil fuel subsitutes in small home industries and even in domestic level. this shift is mainly caused by the ever increasing demand of fossil fuel, mainly lpg which in turn increases its price and restricts its use for small home industries. carbonized briquette is one of the few types of alternative fuel that follows the main directions of biomass conversion which is having good thermal atributes while also being cheap with simple technolgy involved to produce in large quantites. however, this directions puts preasure towards tree harvesting, straining forestry and agriculture sectors. an alternative way in is to utilize tree waste procured from natural tree death or as a result from tree maintenance such as prunning. many studies have assesed that the volume of tree waste can fulfill the energy demands for small home industries and domestic level. from a raw material perspective, the use of biomass from tree waste is preferable than utilizing tree harvest, potentially being more environmental friendly and sustainable as tree waste is mostly under-utilized. furthermore, tree waste is logistically more economical since it is more available in abundance. the most easy way of utilizing this form of fuel is as regular firewood which provides heat for 69 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 cooking. however, due to their random form and high moisture content, regular firewood alone is not considered as a readily alternative fuel source. carbonized briquette is a solid biofuel that can provide heat for cooking. basically, carbonized briquette is made by compacting loose biomass under high pressure in an effort to remove water and increase density. prior to compaction, the biomass undergo carbonization in which volatile matter and excess moisture is removed [4] this process also enhances the caloric value of the end product. a binding agent is also added to increase compaction ease and product durability. as a result, carbonized briquette compared to regular firewood has better combustion attributes due to their higher carbon content. the end product is also more aesthetic pleasing, easy to transport and has a more homogen form which in turn ease its use for both small home industry and domestic purposes [5]. these aspects highlights the potential of carbonized briquette made from tree waste as a solution for sustainable alternative energy. sustainable energy depends on the supply of the material availability. indonesia has the abundance of under-utilized tree waste as a result of its large scale of forestry and agricultural sectors. this paper serves as continuation to previous papers that emphasize production of carbonized briquette made from tree waste, mainly leaves, petiole and branches. in indonesia, langsat (lansium domesticum l.), guava (psidium guajava l.) and rambutan (nephellium lappaceum linn.). are commonly grown as a source of fruit. previous studies have shown that rambutan and langsat (nephelium lappaceum ) has been used as biomass for briquetting [6,7]. however, the branch and leaves of the langsat has not been reported. guava leaves and wood showed a potency of solid densified biofuels in the form of pellet and briquette [8,9]. considering indonesia is the house of the langsat and langsat -duku [10], utilizing of the petiole, leaves, branch those langsat could also give an addition of energy source of biomass. the thermal attributes of each tree waste carbonized briquette produced in this paper was investigated. theoretical background briquetting briquetting is the process of compressing biomass material [11]. it is well known that fixed carbon has a direct link with calorific value. briquetting's caloric value is mostly determined by its quality, which is determined by the amount of water, volatiles, and ash content [12]. its total heating value is predicted to be between 28 and 30 mj/kg. although freshly manufactured charcoal has no water, it can quickly absorb moisture from the air during storage. charcoal, which is often used domestically, has a net caloric value of 28 mj/kg. that implies it has nearly double the energy value of air-dried fuelwood. because of this significant disparity, transporting charcoal over a greater distance is less expensive. the criteria of the energy fuel are cellulose and lignin content. the main ingredient that must be contained in the charcoal briquette raw material is lignocellulose. lignocellulose consists of cellulose, hemicellulose, and lignin. briquetting process has focused on production of smokeless solid fuels from coal and agricultural wastes. however, briquetting of organic materials (agricultural wastes) requires higher pressure as additional forces is needed to overcome the materials springiness of these materials. . 70 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 (a) (b) (c) figure 1. plant leaf, petiole, and branch biomass for sustainable production of future fuels (a) guava (jambu biji), (b) rambutan and (c) langsat. continuously pruning of plant should be conducted in order to prevent the tree plant of risk in electrical powerline. this can be sustainable source of biomass energy during their cycle of life materials and methods the charcoal briquette production comprises of various steps and is depicted on figure 2. tree waste comprising of leaves, petiole and branch of langsat, guava and rambutan were collected from kalibaru region in banyuwangi. any foreign material was then removed by hand. the collected biomass was first prepared by chopping and sun dried to reduce moisture content. each individual biomass was then carbonized seperately in a charcoal retort tube system (designed and fabricated by biophysics lab, dept. of physics, faculty of mathematics and natural sciences, universitas jember) at 400⁰600⁰c for an hour and then left to cool for pulverazation. following pulverazation, the powder was then mixed with corn starch (95%:5%) as binding agent, and mixed until it produce a slurry texture. the slurry was then fed into cylindrical tube molds and 71 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 compressed at 20 n/cm2 and 50 n/cm2 using hydroulic briquette machine (fabricated by biophysics lab, dept. of physics, faculty of mathematics and natural sciences, universitas jember). dwelling time was 30 minutes for each compression. the freshly molded briquettes were taken out from the cyclindrical mold and finaly oven dried for 24 hours at 60 ⁰c. end figure 2. research flowchat results and discussion moisture content of briquette briquette moisture content is an important briquetting parameter. it can be observed that all of the briquettes had less than 8% moisture content, which is a favorable indicator of briquette quality (figure 3). the heating value increases as the briquette's wet basis decreases, but the moisture content must be at an optimal level for the briquettes to perform well in combustion. figure 3 tree waste start preparation carbonization pulverazation and mixing briquetting oven drying analysis 72 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 depicts the moisture content of three distinct briquette materials. it demonstrates that the greater the compaction, the lower the moisture content (50 n/cm2 and 20 n/cm2 were utilized). the guava provided a lower moisture content. however, the moisture content of langsat and guava at of 50 n/cm2 compaction is not significantly different. because the water contents of the materials vary, it is proposed that water content analysis and material modification (e.g., rice husk) be performed prior to the briquetting process [13]. the greater the quality of the carbonized briquettes, the lower the moisture content of the briquettes. the lower moisture level was most likely caused by the drying process in the oven, allowing the water from the carbonized briquettes to evaporate more completely. the statistical analysis using spss revealed that there is a substantial difference in moisture content. figure 3. the moisture content (%) of briquette from rambutan, langsat and guava (jambu biji) from the different of compaction of 20 n/cm2 and 50 n/cm2 energy output of the briquette a statistical test confirmed the findings, revealing that pressure had a significant influence on the energy output created. it demonstrates that carbonized briquettes generate a lot of energy. the biochar/carbonized briquette generated is a suitable alternative energy source to firewood and charcoal, and it may be used indoors since it is a cleaner energy form than un-carbonized briquette [14]. figure 4 shows that the energy output of the three carbonized briquettes does not differ significantly across materials for the same compaction process of 20 n/cm2. it also shows that with the same higher pressure of 50 n/cm2, the briquettes have virtually the same energy output. however, the higher the pressure, the greater the energy output. 73 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 figure 4. the energy output (kj) of briquette from rambutan, langsat and guava from the different of compaction of 20 n/cm2 and 50 n/cm2 under the pressure of 20 n/cm2 for the carbonized briquette, the energy output of rambutan, langsat, and guava is 208.005 kj, 199.151 kj, and 191.025 kj, respectively. rambutan briquettes have the highest energy output, whereas guava briquettes have the lowest energy output with a compaction of 20 n/cm2. the energy production of rambutan, langsat, and guava under 50 n/cm2 pressure is 233.475 kj, 229.230 kj, and 224.985 kj, respectively. ash content ash content vary among the material of the briquetting. national standard of indonesia gives the value of the ash content ≤ 8%. it showed that guava gives the lowest of the ash content compared to the rambutan and langsat carbonized briquettes. the amount of ash in the briquetting material varies (figure 5). rambutan and langsat carbonized briquets have similar values, with approximately 8% for langsat and around 8.1 percent for rambutan, and less than 7% for guava under briquetting with a compaction of 50 n/cm2. the ash content of carbonized briquettes of langsat is in the range of 5 to 7% when compacted at 20 n/cm2, with the lowest ash content being for carbonized briquettes of langsat. except for the ash level of carbonized rambutan briquettes, which was slightly higher than the national standard of indonesia (standart nasional indonesia-sni) of 8%, the findings revealed that all of the material briquettes met the national indonesian standard. 74 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 figure 5. the ash content (%) of briquette from rambutan, langsat and guava from the different of compaction of 20 n/cm2 and 50 n/cm2 rate of combustion of the briquettes figure 6 shows that the rate of combustion of the guava briquette is the greatest among the briquette materials, with the rambutan and langsat briquettes having comparably high rates of combustion under the compaction of 20 n/cm2. it can also be observed in the figure that the compaction of 50 n/cm2 resulted in a faster rate of combustion than the rate of 20 n/cm2 from all of the materials utilized. under a compaction of 50 n/cm2, the rates of combustion of rambutan, langsat, and guava are 0.027 (g/s), 0.029 (g/s), and 0.042 (g/s), respectively. while the rate of combustion is about 0.021 (g/s), 0.021 (g/s), and 0.033(g/s) under the compaction of 20 n/cm2 respectively. from the data, it can be observed that the guava briquette has the greatest rate of combustion, with a compaction of 50 n/cm2. this is because the rate of combustion is related to the density and ash content of the briquettes. the longer the rate of combustion, the higher the density and ash content. the length of the combustion process is another aspect that influences the rate of combustion. the pressure and substance of the briquette, as well as the rate of burning, had statistically significant effects in the two-way anova. figure 6. rate of combustion of carbonized briquette of rambutan, langsat and guava under the compaction of 20 n/cm2and 50 n/cm2 75 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 briquetting performance in the table 1, it can be seen that the performance of the carbonized briquette are varies among the material briquettes and under the different compaction. there is another requirement of the briquette that should be not easy to break, not brittle and have smooth surface. it should also not leave black to the hand [15]. it can be seen that there are different results of the briquette under pressure 20 n/cm2 and 50 n/cm2 for the same material of the briquette such as that under the pressure of 20 n/cm2 showed of more sturdy of the briquette, not easy to brake, compact but might have different appearance of surface, either rough (i.e., rambutan and guava) or soft (langsat). while under pressure of 50 n/cm2, the appearance of the briquette seems brittle, easy to brake, not compact, with the rough surface for both rambutan and guava, and soft for langsat. however, all the carbonized briquette qualified for small industry and household demand. table 1 the performance of the carbonized briquette of rambutan, langsat and guava under pressure of 20 n/cm2 and 50 n/cm2 pressure (n/cm2 rambutan langsat guava 20 sturdy, not brittle, not easy to brake compact and rough surface sturdy. not brittle, not easy to brake and soft/good surface sturdy, not brittle, not easy to brake, compact, and rough surface 50 not so sturdy, brittle, easy to brake, not compact and rough surface not so sturdy, brittle, easy to brake, not compact, soft surface not so sturdy, easy to brake, not compact, rough surface conclusions the chemical structure of the sample and its density suggest that briquettes formed from tree debris of langsat, guava, and rambutan have mechanical and thermal capabilities that may be employed as briquettes for diverse industrial purposes. with this potential of alternative and sustainable energy, the prospect of diversity as a home for the tree plant was recommended. because the fruit is a good source of vitamins and bioactive compounds, it has a lot of advantages. briquetting technology might be employed as a solution for home trash and the demand for sustainable energy for the area in the future, given the briquette's characteristics and the continual generation of biomass waste. 76 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 acknowledgements the author would like to thank to biophysics group for assisting in the research. the author also in thank to the r. rizki akbar, for english correction. no conflict of interest of the journal. references [1] ren21.2021 renewable 2021 global status report (paris: ren21 secretariat). isbn 9783-948393-03-. [2] s.y. kpalo, m.f. zainuddin., l.a. manaf., and a.m. roslan. 2020. a review of technical aand economic aspects of biomass briquetting. sustainability. 12 (11), 4609. https://doi.org/10.3390/su12114609 [3] s.c. karmaker, md. m rahman, s hosan.and b.b. saha. 2020. the impact of biomass energy consumption on human development; evidence from asian countrues. proceeding of international exchange and innovation conference on engineering & sciences (ieices) 6: 204-211. https://doi.org/10.5109/4102489 [4] m lubwama, v.a. yiga, i ssempijja and h.n lubwama. 2021. thermal and mechanical characteristics of local firewood species and resulting charcoal produced by slow pyrolysis. biomass conversion and biorefinery. https://doi.org/10.1007/s13399-021-01840-z [5] a.y. nurhayati, y.c hariadi., and w. hasanah. 2016. endeavoring to food sustainability by promoting corn cob and rice husk briquetting to fuel energy for small scale industries and household communities. agriculture and agricultural science procedia. volume 9 p.386-395. 2016. elsevier. https://doi.org/10.1016/j.aaspro.2016.02.154 [6] a. brunerová, h. roubik., m. broźek, d, herak, v sleger and j mazacova. 2017. potential of tropical fruit waste biomass for production of bio-briquette fuel: using indonesia as an example. energies. 10 (12), 2119. doi:10.3390/en10122119 [7] l ni’mah. 2020. pembuatan briket dari kulit buah langsat. buletin profesi insinyur 3(2): 103-108; http://dx.doi.org/10.20527/bpi.v3i2.75 [8] v.m ruiz-garcía, m.y. huerta-mendez., j.c. vázquez-tinoco, j.j alvarado-flores., v.m. berrueta_soriano, p. lópez-albaráan; o masera and j.g. rutiaga_quiñones. 2022. pellets from lignocellulosic material obtained from pruning guava trees: characterization, energy performance and emissions. sustainability 14, 1336. https://doi.org/10.3390/su1403133 [9]] t. ivanova, a.h.m hernandez, j. bradna, e.f. cusimani, j. c.g montoya and d.a.a. espinel. 2018. assessment of guava (psidium guajava l.) wood biomass for briquettes production. forests. 9(10), 613. doi:10.3390/f9100613 [10] h.m. abdallah, g. a. mohamed, and r.m. ibrahim. 2022. lansium domesticum – a fruit with multi-benefits: traditional uses, phytochemicals, nutritional value, and bioactivities., nutrients. vol 14, no 1531. https://doi.org/10.3390/nu1407153 https://doi.org/10.1016/j.aaspro.2016.02.154 77 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 68-77 eissn : 2747-173x submitted : april 1, 2022 accepted : may 1, 2022 online : may 31, 2022 doi : 10.19184/cerimre.v5i1.31509 [11] a. kaur, m. roy., and k. kundu. 2017. densification of biomass by briquetting; a review. international journal of recent scientific research. vol 8. issue 10, pp.20561-20568. doi: 10.24327/ijrsr [12] e.a. sanhez., m. laeng., m.b. pasache., and m.e. garcia. 2014. development of briquettes from waste wood (sawdust) for use in low-income households in piura, peru. proceedings of the world congress on engineering. voll ii. wce. 2014, july 2-4, 2014 london. uk. ssn: 2078-0966 (online) [13] a.a.h. saeed, n.y. harun., m.r. bilad., m.t. afzal., v.d. vinayagam, and h.k. afolabi. 2021. moisture content impact on properties of briquette properties from rice husk waste. sustainability, 13 (6), 3069. https://doi.org/10.3390/su13063069 [14] a.i. abimbola and o. o. yekin. 2017. thermal energy estimates of briquettes produced from bio char sawdust of gmelina arborea. aascit journal of energy 4(1): 1-4. [15] s.w. murni., t.m. setyoningrum., m.m.a. nur. 2021. production of briquettes from indonesia agricultural biomass waste by using pyrolisis process and comparing the characteristics. eksergi. vol 18, no. 1. 2021. issn:1410-394x. 80 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 lift force of airfoil (naca 0012, naca 4612, naca 6612) with variation of angle of attack and camber: computational fluid dynamics study mariza d. ardany 1 , paken pandiangan 2 and moh. hasan 3 1 kajian komputasi aplikatif, jalan simpang panji suroso no.100, polowijen, kec. blimbing, kota malang 65126, jawa timur, indonesia 2 universitas terbuka indonesia, jalan cabe raya pondok cabe 15418, jakarta, indonesia 3 departement of mathematics, faculty of mathematics and natural sciences, universitas jember, kalimantan street no. 37, jember 68121, indonesia a marizaardany22@gmail.com abstract. airfoil is a cross section from air plane wings can affect aerodynamic performance to lift force (fl). the lift force generated by airfoil has different values due to several external and internal factors, including angle of attack, flow rate and camber. to find the lift force of airfoils with different cambers and variations angle of attack and then flow rate can use computational fluid dynamics simulation. computational fluid dynamics is simulation on a computer that can complete systems for fluid, heat transfer and other physical processes. this research using computational fluid dynamics simulation performed by solidworks, with naca airfoil type which has different camber naca 0012, naca 4612 and naca 6612. the angle of attack used in research was 0 o , 4 o , 8 o , 12 o , 16 o and 20 o . flow rate used in research was 20m/s, 40 m/s, 60 m/s, 80 m/s and 100 m/s. from this research will be the bigger camber can produce a greater force lift. in addition, the greater airfoil flow rate can produce a greater force lift. this research also that the connection between force lift with coefficient lift (cl) is nonlinear quadratic form. keywords: airfoil naca, force lift, angle of attack, flow rate, computational fluid dynamics. introduction airfoil is a cross section of the wing that result from the perpendicular of the aircraft wing [1]. airfoil which is often used in the aviation is asymmetric airfoil, because it has a geometry with aerodynamic characteristics that can increase the value of the lift coefficient (cl) [2]. the lift force (fl) of an airplane is affected by difference air pressure around the airfoil [3]. difference pressure around the airfoil, due to differences in flow rate at the upper and lower airfoil. another factor that affects lift force (fl) on an airplane is angle of attack. angle of attack is the angle between chord line and direction of the wind. chord line is a line that connects leading edge and trailing edge of the airfoil [3]. the development of technology in order to analyze aerodynamic character and experimental methods. the development of aerodynamics technology conducting experiments on airfoil configurations to find out specifications, get inaccurate result and require large cost in the testing process. another problem that appear in the experimental method is less flexible during the result-taking process because it only uses tunnels for airfoil testing. overcome the shortcoming of the experimental method in analyzing airfoil characteristics, the simulation method is solution. the simulation method offers convenience in observing or predicting variations on the value of physical quantities. simulation method is a method that can be used to analyze airfoils with accurate result and low operating cost when compared to experimental 81 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 methods [4]. one of the analysis system simulation methods used to analyze airfoil characteristics is cfd [5,6]. computational fluid dynamic (cfd) is a computer – based for simulating fluid systems, head transfer and other physical processes. the principle of cfd is to solve fluid dynamics problems based on certain formula, such as navier-stokes [7]. research with the cfd simulation method was conducted to determine force lift (fl) from the effect of thickness, angle of attack and another factor of the airfoil. research on airfoils using the cfd simulation method was carried out by guerrero (2009) about the effect of variation camber on airfoil performance in the naca 0012, 2212, 2412, 4412, 2612, 4612, 6612 dan selig s122. maximum airfoil thickness at naca is 12% from chord line with difference variation camber. the result of these research indicates that the naca 6612 has a greater lift coefficient value than naca 0012. naca 6612 is an asymmetrical airfoil shape because it has certain camber thickness, while naca 0012 is symmetrical airfoil because it doesn’t have a camber thickness value. the result in this research indicate that the greater thickness of the camber, the greater lift force (fl) [8]. other research on airfoils using the cfd simulation method was carried out by jain et al. (2015) about the characteristics of the reynolds number on an airfoil on the effect of variation in the angle of attack and flow rate. this study a variation of angle of attack, namely 0 , 4 o , 8 o , 12 o and 16 o . this research, it can be concluded that the greater the reynolds number, the smaller lift coefficient (cl) [9]. the weakness of previous research is that only focuses on effect of the angle of attack on the resulting lift force (fl). the result of research used a cfd simulation method and experimental method little that analyzed the effect of variations in angle of attack and flow rate to determine resulting force lift (fl). previous research only focused on one or two variables such as the variation in angle of attack with flow rate in one type of airfoil or camber variations with angle of attack. research that discusses the effect of the variations in the angle of attack and flow rate with various types of naca airfoils on one topic is still rare, so that is the basis for this research. focus of the research that determine the effect of variations in angle of attack and flow rate on various types of naca airfoils on the resulting force lift (fl). airfoil that will be used in this research is naca (national advisory committee for aerobatics) symmetry and asymmetry airfoil type. the airfoil that will be used in this research are naca 0012, naca 4612 and naca 6612. this research was conducted to determine how the characteristics of the airfoil lift force (fl) on naca airfoil with different cambers. from this research, two values will be used to determine the characteristics of the airfoil force lift (fl), namely the value of the force lift (fl) and coefficient lift (cl). from tis research it is also known ow the connect between forces lift (fl) and coefficient lift (cl). this research uses variations in the angle of attack and flow rate, these variations are used to determine how the effect of force lift (fl) characteristics of the naca airfoil. theoretical background naca airfoil airfoil is a form of aircraft wing that can generate aerodynamic lift. the force lift (fl) is generated from a cross section perpendicular to the wing of the airplane. airfoil is a two – dimensional 82 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 aircraft wing shape [10]. this study uses an airfoil naca four digit series. airfoil naca series four or so called naca xxxx, developed in 1932 with various airfoil shapes. the first digit of a naca series four airfoils is the percent of maximum camber to chord. the second digit is one tent of the maximum position of the camber with respect to the cord of the leading edge [11]. the last two digits of a series four naca airfoil represent the percent thickness of the airfoil with the chord. airfoil has sections with different functions. the airfoil parts can be seen in figure 1. figure 1. part of the airfoil [2] explanations of figure 1:  leading edge is the front of the airfoil,  trailing edge is the back of the airfoil,  chord c is the distance between leading edge and training edge,  chord line is a straight line connecting the leading edge and training edge,  mean camber line is an equal dividing line between the upper and lower airfoil,  thickness is the maximum distance between the upper and lower surface of the airfoil,  camber is the maximum distance of the chord line with chamber line [12]. airfoil is a geometric shape of an airplane wing in the fluid flow which produces a lift that is greater than drag. the lift of large airfoil is greater than the drag on fluid flow, causing the airfoil to be chosen in airplane wing components because it is very efficient [13]. the lift of an airfoil is formed because there is a difference in pressure between the upper and lower surfaces of the airfoil, which gives rise to the resultant force perpendicular to the direction of the fluid flow [14]. the difference in pressure between the front and rear of the airfoil that causes a resultant force that is parallel to the arrival of the fluid flow is usually called drag. forces acting on the plane can be seen from figure 2. figure 2. forces acting on the plane [2] 83 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 the forces acting on the plane are:  thrust is the force generated by the engine (power plant).  drag is the force that pulls the airplane backwards.  weight is the force that comes from the combined weight of the aircraft’s payload, such as crew, fuel and cargo or baggage.  lift is the force perpendicular to the direction of flight through the center of lift of the wing [11]. coefficient lift (cl) force lift (fl) of the airfoil depends on the coefficient of lift (cl) which is influenced by size of the camber and angle of attack. greater value of the angle of attack causes the fluid flow above the airfoil surface to from dead air behind airfoil. fluid flow moving in a circle opposite to the free stream flow is reversed flow. the split fluid flow is due to the viscosity effect. the separation of the fluid flow causes a reduction in lift or coefficient lift (cl), and cause the amount of drag due to pressure drag, this condition is called a stall. stall is a decrease in force lift (fl),which is caused by an increase in angle of attack or an increase in angle of attack that exceeds the critical angle of attack which allows a slowdown on the underside of the aircraft wing [15]. drag is force whose direction is parallel to the direction of fluid flow [16]. drag in the from of skin friction drag (fdf) arising from the presence of shear stress and pressure drag (fdp) arising from fluid pressure. profile drag is the sum of skin friction drag (fdf) and pressure drag (fdp) shown from figure 3. figure 3. profile drag [17] the resultant of this forced will produce the following equation: dfy = -( ( (1) the component of the force towards the y – axis is the force lift (fl), can be formulated as follows: l = ∫ ∫ ∫ (2) lift force (fl) can be expressed as a dimensionless number. lift force (fl) is a component of the force perpendicular to the direction of free stream flow [16]. the equation for the coefficient lift (cl) can be written as follows: 84 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 cl = (3) explanation of equation (1), (2) and (3):  l is lift force (n)  is the direction of fluid flow that passes through the object  is the density of the fluid (kg/m 3 )  is surface of the object through which the fluid passes (m 2 )  cl is coefficient lift computational fluid dynamics (cfd) computational fluid dynamics (cfd) is one of the existing technological developments to produce information about fluid flow. cfd simulation method used in solving fluid problems using numerical methods. the cfd method is widely used because it can reduce costs in analyzing a system [11]. cfd method can also reduce the time in data collection, when compared to experimental methods [18]. the geometry in cfd is quite complex. fluid flow in cfd will be divided into grid and nodes elements, by using that simulates partial differential equations. the advantage of using the cfd method is that it can be used as a more practical calculation, making it easier for differential operations [19]. the simulation using the cfd method is shown in figure 4. figure 4. cfd simulation method with meshing airfoil naca [19] the mathematical solution to solving cfd simulation method uses newton’s second lawa of motion combined with stoke’s stress law, yields three momentum equations for velocity in direction xj (j = 1, 2, 3). the cfd mathematical solution using the rans equation also takes into account the reynolds number value, which aims to determine whether the fluid flow is laminar of turbulent. distribution of the rans equation can be used to solve cfd simulation method by taking into account the fluid flow formed. the cfd simulation method solution also uses several input parameters related to the reynolds and rans equation. these parameters include flow rate, temperature, density, pressure, viscosity and length of fluid flow through the object. this parameter will effect the value of the resulting reynolds number and indicate the type of fluid flow formed. these parameters in the cfd simulation method [20]. research methods 85 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 this research method includes design and simulation using solidworks software. this simulation is done sing an airfoil naca 0012, naca 4612 and naca 6612. the variations used in this simulation are angle of attack and flow rate. the angle of attack used in this simulation is 0 o , 4 o , 8 o , 12 o , 16 o and 20 o . the flow rate used in this simulation is 20 m/s, 40 m/s, 60 m/s, 80 m/s and 100 m/s. this variation used to determine the characteristics of the naca airfoil at each camber based on resulting of force lift (fl) and coefficient lift (cl). figure 5. naca 0012 design with a chord line length of 1 m figure 6. naca 4612 design with a chord line length 1 m figure 7. naca 6612 design with a chord line length 1 m table 1. boundary parameter parameter value unit temperature 300 [21] k atmosphere pressure 101325 [21] pa density of air 1.225 [21] kg/m 3 air viscosity 1.7894 x 10 -5 [21] m 2 /s chord line length 1 m level initial mesh 4 [22] minimum gap size 0.767660947 [22] m the simulation process with the cfd method: 1. design the airfoil geometry on solidworks software. 2. enter the boundary parameter on solidworks software. 3. simulated for each airfoil with variations in angle of attack and flow rate. 4. plot the result in the form of force lift (fl) and coefficient lift (cl) in excel software. 86 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 results effect of angle of attack and flow rate variations on te force lift (fl) and coefficient lift (cl) of the naca airfoil figure 8. graph (fl) with aoa and flow rate on naca 0012 figure 9. graph (fl) with aoa and flow rate on naca 4612 figure 10. graph (fl) with aoa and flow rate on naca 6612 influence of variation of angle of attack and flow rate on an airfoil at naca 0012, naca 4612 and naca 6612 to the value of force lift (fl), based on figure 8, figure 9 and figure 10 that is, the greater the angle of attack and flow rate, the greater the lift, but the angle of attack is too large in value that exceeds the critical angle of attack or produces maximum force lift (fl max), it can cause the naca airfoil to experience a stall. stall is a condition where the lift will decrease after experiencing the maximum lift, this is because the enlarged angle of attack exceeds the 87 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 angle of attack which shows the maximum lift. the resulting value of maximum force lift (fl max) for each naca airfoil will be different. the difference in the value of maximum force lift (fl max) for each naca airfoil is different due to the effect of different camber values. the greater camber, the greater force lift (fl). the camber value of the naca airfoil used in this research as a different value, such as naca 0012 has a camber value 0. airfoil naca 4612 has a camber value in the first digit is 0,04 and 0,4 chord camber position. airfoil naca 6612 has camber value in the first digit is 0,06 and 0,6 chord camber position. the maximum force lift (fl max) values of the naca 0012 airfoil at flow rates of 20 m/s, 40 m/s, 60 m/s, 80 m/s dan 100 m/s are 43,4 n; 172,8 n; 388,5 n; 687,4 n and 1077,5 n with the angle of attack at an flow rate of 20 m/s to 40 m/s is 16 o while at an flow rate of 60 m/s to 100 m/s is 12 o . the maximum force lift (fl max) values of the naca 4612 airfoil at flow rates of 20 m/s, 40 m/s, 60 m/s, 80 m/s and 100 m/s is 81,1 n; 328,7 n; 741,6 n; 1320,9 n and 2067,9 n with angle of attack is16 o . the maximum force lift (fl max) values of the naca 6612 airfoil at flow rates of 20 m/s, 40 m/s, 60 m/s, 80 m/s and 100 m/s are 92,0 n; 374,7 n; 845,9 n; 1516,3 n and 2384,1 n with angle of attack is16 o . the maximum force lift (fl max) performance obtained on thenaca 0012 airfoil based on the result obtained is 1077,5 n with an angle of attack and flow rates of 12 o and 100 m/s. the maximum force lift (fl max) performance obtained on thenaca 4612 airfoil based on the result obtained is2067,9 n with an angle of attack and flow rates16 o and 100 m/s. the maximum force lift (fl max) performance obtained on thenaca 6612 airfoil based on the result obtained is 2384,1 nwith an angle of attack and flow rates16 o and 100 m/s. based on the maximum force lift (fl max) generated by the airfoil that as the largest lift are naca 6612 because it as the largest camber. camber is two leading digits of the naca four – digit series. the symmetry of an airfoil will depend on the camber value. camber which as a value of 0, is type of symmetrical airfoil, such as naca 0012, while camber which has a value like naca 4612 and naca 6612 is a type of asymmetric airfoil. figure 11. distribution of the flow rate around the airfoil naca 0012 with angle of attack 12 o and flow rate 100 m/s 88 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 figure 12. distribution of pressure around the airfoil naca 0012 with angle of attack 12 o and flow rate 100 m/s figure 13. distribution of the flow rate around the airfoil naca 4612 with angle of attack 16 o and flow rate 100 m/s figure 14. distribution of pressure around the airfoil naca 4612 with angle of attack 16 o and flow rate 100 m/s 89 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 figure 15. distribution of the flow rate around the airfoil naca 6612 with angle of attack 16 o and flow rate 100 m/s figure 16. distribution of pressure around the airfoil naca 6612 with angle of attack 16 o and flow rate 100 m/s the effect of variations in flow rate in this research can affect the lift generated for each airfoil. figure 11, figure 13 and figure 15 show the distribution of flow rate around the airfoil at a certain angle of attack. result on figure 11, figure 13 and figurer 15 it can be seen that the flow rate flowing at the upper of tr airfoil surface has a greater value, when compared to the lower of airfoil. the difference in flow rate at the upper and lower of the airfoil surface is in accordance with bernaulli’s law of lift on the aircraft. because the difference in flow rate at the upper of the airfoil causes the lower pressure of the airfoil to be greater than the pressure on the upper surface of the airfoil. this statement is in accordance with the result of our research indicated by figure 12, figure 14 and figure 16. because the pressure below the airfoil surface is greater than the upper of airfoil surface, it causes lift, this statement is in accordance with the result figure 12, figure 14 and figure 16. thus, if the flow rate passing through an airfoil is greater, the lower pressure airfoil surface will be even greater when compared to the upper surface of the airfoil. so that the greater flow rate passing through an airfoil, the greater force lift (fl) generated by an airfoil. 90 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 connect coefficient of lift (cl) with force lift (fl) figure 17. graph nonlinear cl with aoa on airfoil naca 0012 figure 18. graph nonlinear fl with aoa on airfoil naca 0012 figure 19. graph nonlinear cl with aoa on airfoil naca 4612 figure 20. graph nonlinear fl with aoa on airfoil naca 4612 91 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 figure 21. graph nonlinear cl with aoa on airfoil naca 6612 figure 22. graph nonlinear fl with aoa on airfoil naca 6612 the result of the research on the connect between the coefficient of lift (cl) and the force lift (fl) in this research can be said to be quadratic nonlinear, this is because the regression coefficient value shown is close to 1, the coefficient of lift (cl) and force lift (fl), have a regression coefficient value, the same one. the regression coefficient is the value of graph showing how the graph is getting more linear or nonlinear wen it approaches 1. the regression coefficient values shown in the results of this research are close to 1, for nonlinear quadratic graph. so, it can be concluded that the connect coefficient of lift (cl) and force lift (fl) is nonlinear quadratic. conclusion the effect of angle of attack on naca airfoils for different cambers is that the greater the angle of attack, the greater resulting force lift (fl), but the angle of attack is too large in value that exceeds the critical angle of attack or produces maximum force lift (fl max), it can cause naca airfoil stalled. the naca airfoil that produces the greatest maximum lift force there is naca 6612, at angle of attack 16 o and flow rate 100 m/s. the effect of flow rate on naca airfoils for various cambers is that the greater flow rate, the greater force lift (fl). connect coefficient of lift (cl) and force lift (fl) is nonlinear quadratic. references [1] e. houghton, p. carpenter., et al, 2013, aerodynamics for engineering students, amsterdam: elsevier, chapter 6. [2] z. wei, c. wan., et al, 2016, geometrical effects on the airfoil flow separation and transition, international journal computers & fluids, vol. 116, page 60-70. [3] j. john, 2010, fundamental of aerodynamics, new york: mcgraw-hill. 92 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 [4] a. a. yassin and a. m. a. elbashir, 2011, simulation around airfoil naca 4412, thesis, faculty of engineering, university of khartoum, sudan. [5] r. anggraeni, 2019, effect of angle of attack on pressure and lift coefficient of onera oa206 wing model using computational fluid dynamics method, computational and experimental research in materials and renewable energy (cerimre), volume 2, issue 2, page 81-97. [6] s. a. ayudia, a. arkundato, and l. rohman, 2020, study of vortex generator effect on airfoil aerodynamics using the computational fluids dynamics method, computational and experimental research in materials and renewable energy (cerimre), volume 3, issue 2, page 68-74. [7] h. lomax, d. w. zing., et al, 1999, fundamental of computational fluid dynamics, amerika: university of toronto. [8] j. e. guerrero, 2009, effect of cambering on the aerodynamic performance of heaving airfoils, bionic enginering, vol 6, page 398 – 407. [9] s. jain, n. sitaram., et al, 2015, effect of reynolds number on aerodynamics of airfoil with gurney flap, international journal of rotationing machinery, vol. 2015, page 1-10. [10] y. wibisono, g. nugroho., et al, 2013, studi karakteristik aliran tiga dimensi dan perpindahan panas pada cascade airfoil dengan pengaruh clearance, teknik pomits, vol. 2, no. 1, page 110 – 115. [11] m. mulyadi, 2014, analisis aerodinamika pada sayap pesawat terbang degan menggunakan software berbasis computational fluid dynamics (cfd), artikel universitas gunadarma, page 1-13. [12] m. f. hidayat, 2014, analisa aerodinamik airfoil naca 0012 dengan ansys fluent, kajian teknologi, vol. 10, no 2, page 83 – 92. [13] m. m. lubis, 2012, analisa aerodinamika airfoil naca 2412 pada sayap pesawat model tipe glider dengan menggunakan software berbasis computational fluid dinamic untuk memperoleh gaya angkat maksimum, e – dinamis, vol. 2, no. 2, page 23 – 33. [14] t. nurcahyadi and sudarja, 2008, pengaruh lokasi ketebalan maksimum airfoil simetris terhadap koefisien angkat aerodinamisnya, ilmiah semesta teknika, vol.11, no. 1, pp. 110 – 124. [15] j. c. kewas and m. ali, 2020, analisis akibat perubahan kecepatan aliran udara dan sudut serang pada airfoil naca 0015 dalam wind tunnel sub sonic, jurnal frontiers, vol.2, no. 1, pp. 71 -79. [16] r. ridha, 2017, studi numerik karakteristik aliran tiga dimensi di sekitar airfoil naca 0012 dengan backward swept angle 0 o , 15 o , dan 30 o , skripsi, fakultas teknik mesin, institut teknologi sepuluh nopember, surabaya, indonesia. [17] a. sayma, 2009, computational fluid dynamics, new york: venus publishing aps. 93 computational and experimental research in materials and renewable energy (cerimre) volume 4, issue 2, page 80-93 eissn : 2747-173x submitted : august 10, 2021 accepted : october 10, 2021 online : november 24, 2021 doi : 10.19184/cerimre.v4i2.28372 [18] b. r. muson, d. f. young., et al, 2009, fundamental of fluid mechanics, united states of america: jhon wiley & sons. [19] f. m. white, 1998, fluid mechanics, united states: mcgraw-hill series in mechanical engineering. [20] a. w. date, 2005, introduction to computational fluid dynamic, united kingdom: cambridge university press. [21] m. kavadiya, 2013, cfd analysis of pressure coefficient for naca 4412, international journal of engineering trends and technology (ijett), vol. 4, no. 5. [22] a. m. gofar, 2018, pemilihan sudut pasang airfoil naca 2412 pada tail uav dengan menggunakan software berbasis computational fluid dynamic untuk memperoleh gaya angkat optimal, skripsi, dept. teknologi industri., universitas islam indonesia., yogyakarta, indonesia. 105 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 innovative compact molten salt reactor (icmsr) analysis for mo-99 production iza shafera hardiyanti1,a, a suparmi1 and andang widi harto2 1physics department, universitas sebelas maret, surakarta, indonesia 2nuclear physics department and engineering physics department, universitas gadjah mada, yogyakarta, indonesia aemail: izashafera@student.uns.ac.id abstract. mo-99 isotope production calculation in the icmsr (innovative compact molten salt reactor) with the computer code mcnp6 has been carried out. icmsr is a conceptual design of the msr type reactor that uses naf-thf4-uf4 fuel with an enrichment of 235u of 19.75%. this reactor operates in thermal neutron spectrum with a graphite moderator. icmsr is a power reactor that produces mo-99 as a byproduct. calculations carried out for 12 days of operation show that the reactor condition is still critical so that there will be no intervention from refueling. the total mo-99 produced until the 12th day is 9.118 x 106 ci. mo-99 can be extracted from the reactor as long as the power reactor is operating so it will be economically advantageous. keywords: 99mo, isotope production, icmsr, mcnp, criticality introduction almost all hospitals in the world use radioisotopes in medicine. most of it is for diagnosis. technetium-99m (𝑇1/2 = 6.02 ℎ) is the most widely used radioisotope [1]. more than 80% of radiodiagnostic procedures in the world use this isotope [2, 3, 4]. technetium-99m can be generated from the decay of the parent nuclide molybdenum-99 (𝑇1/2 = 66 ℎ) [5]. the mo-99 will decay to tc-99m which then decays to its ground state tc-99 by emitting 143 kev 𝛾 −rays which are known to have the same wavelength as diagnostic x-ray devices. the tc-99m is ideal for diagnostic because of its short half-life so it is safe for patients [6]. however, this also makes it difficult to supply to medical centers. to solve the problem of sending tc-99m to end user, a generator is used. a generator is a system that contains a radioactive parent nuclide with relatively long halflife that decays into short-lived daughter nuclides [7]. the generator used here refers to the mo99 generator. the five main supply countries of mo-99 are canada, belgium, france, netherlands and south africa. most isotopes are generated from research reactors [8]. in 2008, shortages of tc-99m began to emerge as the two mo-99 reactors that supply 66% of the world’s supply was shut down for maintenance. that reactor is national research universal (nru) in canada and petten nuclear reactor (hfr) in netherlands [9, 10]. discontinuation of isotope supply from both reactors led to many delays and cancellations of medical procedures. the situation is getting worse: firstly, the reactor is old, secondly, using highly enriched uranium (heu) which is not compatible with nonproliferation [11]. in order to meet the need of the domestic market, several research and development were carried out. one of the parties authorized to produce mo-99 is pt inuki. however, the production is not 106 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 sufficient to meet national needs [12]. from the results of the research reactor (rsg gas), the production capacity of mo-99 is 300 ci per batch (week) [13]. the development of reactors to produce radioisotopes is also being carried out, i.e samop and camolyp [12, 14, 15]. an alternative technology that can support the fulfillment of the growing demand for mo-99 is molten salt reactor (msr) [16]. the big advantage of using msr for the production of mo-99 is the possibility of online extraction [17]. in this study, we propose innovative compact molten salt reactor (icmsr). icmsr is a power reactor, not a special reactor to produce mo-99. however, during its operation, this reactor produces by-products, one of which is mo-99. so this research was conducted to calculate and find out how much amount of mo-99 can be produced from reactor operation for support reactors such as samop and camolyp to supply this isotope. theoretical background the production of mo-99 in general can be carried out in two ways, namely: fission fragments from u-235 and neutron capture reactions from mo-98. when the u-235 is hit by thermal neutrons, the atomic nucleus to become unstable and lose its shape, then split into smaller elements while releasing heat energy and releasing 2-3 new neutrons. one of those elements is mo-99. in addition, neutron capture by m-98 can also produce mo-99 accompanied by 𝛾 −ray emission. however, the production of mo-99 from capture reaction is not used for commercial scale production because it is inefficient [18]. thus, the production of this isotope depends on the fission reactions in nuclear reactors. molybdenum is considered a noble metal in molten salt so it is easily reduced in molten [19]. the reactor that uses molten salt is the molten salt reactor (msr). the ability of msr to produce mo99 has been carried out and shows good results [20]. the accumulation of each isotope in a nuclear reactor depends on fission, decay, activation and extraction [17]. this can apply to any isotope, not just mo-99. firstly is fission. the rate equation for the fission reaction can be written as: �̂�𝑓 × 𝑌𝑖 = 𝐹𝑃 𝑔𝑒𝑛𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒 (1) where, �̂�𝑓 = 𝑝𝑜𝑤𝑒𝑟 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑒𝑛𝑒𝑟𝑔𝑦 𝑟𝑒𝑙𝑒𝑎𝑠𝑒/𝑓𝑖𝑠𝑠𝑖𝑜𝑛 , 𝑌𝑖 is the fission product yield per fission. the subscript 𝑖 refers to the isotope of interest. secondly is decay. the decay equation can be divided into two, namely the decay of the parent isotope and the decay of the isotope of interest. the generation of isotopes from parent isotopes can be written as: ∑ 𝛽𝑝𝜆𝑝𝑁𝑝 = 𝑑𝑒𝑐𝑎𝑦 𝑜𝑓 𝑝𝑎𝑟𝑒𝑛𝑡 𝑖𝑠𝑜𝑡𝑜𝑝𝑒𝑠𝑝 (2) where, 𝛽 is the branch fraction, 𝜆 is the decay constant and 𝑁 is the number density. the subscript 𝑝 refers to the parent isotopes. this equation is especially important for isotopes which have short half-lives. this isotope will remove and decay into its daughter isotopes. the decay of 107 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 the isotope of interest is also needed if isotope unstable and decay. this equation can be written as: −𝜆𝑖 𝑁𝑖 = 𝑑𝑒𝑐𝑎𝑦 𝑜𝑓 𝑡ℎ𝑒 𝑖𝑠𝑜𝑡𝑜𝑝𝑒 𝑜𝑓 𝑖𝑛𝑡𝑒𝑟𝑒𝑠𝑡 (3) where, 𝜆 is the decay constant and 𝑁 is the number density. the subscript 𝑖 refers to the isotope of interest. thirdly is activation. activation occurs when a neutron is absorbed by an isotope. activation of a nuclear reaction depends on the type of isotope, the energy of the neutron and the isotopic number density. in reactors where the fuel is considered homogeneous and has uniform neutron energy such as msr, the activation equation can be approximated by the following equation �̂�𝑖 𝑥 = 𝑁𝑖 𝜎𝑖 𝑥 𝜙 = 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒 (4) where, �̂� is reaction rate, 𝜎 is microscopic cross section, 𝜙 is neutron flux. the superscript 𝑥 refers to nuclear reaction of interest. the neutron flux in this equation can be eliminated by looking at the relationship between the reaction rates of two different isotopes by assuming that the flux is mono energetic. �̂�𝑖 𝑥 𝑁𝑖𝜎𝑖 𝑥 = �̂� 𝑗 𝑦 𝑁𝑗𝜎𝑗 𝑦 = 𝜙 (5) so the activation equation can be rewritten as follows: �̂�𝑖 𝑥 = 𝑁𝑖𝜎𝑖 𝑥 𝑁𝑗𝜎𝑗 𝑦 �̂�𝑗 𝑦 (6) the nuclear reaction we want to observe on activation is an isotope capture reaction in a fission fuel, so the equation becomes: �̂�𝑖 𝑐 = 𝑁𝑖𝜎𝑖 𝑐 𝑁𝑓𝑢𝑒𝑙𝜎𝑓𝑢𝑒𝑙 𝑓 �̂� 𝑓 (7) where, superscript 𝑐 refers to capture reaction and superscript 𝑓 refers to fission reaction. activation can do two things: generate isotopes and remove isotopes. equation (7) refers to removal of the isotope due to activation. meanwhile, the generation of isotopes produced from the activation product precursors can be written by replacing the subscript 𝑖 with the subscript 𝑎. the total activation equation is as follows: − 𝑁𝑖𝜎𝑖 𝑐 𝑁𝑓𝑢𝑒𝑙𝜎𝑓𝑢𝑒𝑙 𝑓 �̂� 𝑓 + 𝑁𝑎𝜎𝑎 𝑐 𝑁𝑓𝑢𝑒𝑙𝜎𝑓𝑢𝑒𝑙 𝑓 �̂� 𝑓 = 𝑡𝑜𝑡𝑎𝑙 𝑎𝑐𝑡𝑖𝑣𝑎𝑡𝑖𝑜𝑛 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 (8) later the isotope of interest will be extracted, the extraction of isotopes such as mo-99 which is classified as a noble metal fulfills the equation 108 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 −𝑘𝑐 𝐴𝑁𝑖 = 𝑒𝑥𝑡𝑟𝑎𝑐𝑡𝑖𝑜𝑛 (9) where, 𝑘𝑐 is the mass transfer coefficient, 𝐴 is the surface area available for extraction and n is number density. so that the desired isotope accumulation equation in the reactor can be written: 𝑑𝑁𝑖 𝑑𝑡 = �̂�𝑓 𝑌𝑖 − 𝜆𝑖 𝑁𝑖 + ∑ 𝛽𝑝𝜆𝑝𝑁𝑝𝑝 − 𝑁𝑖𝜎𝑖 𝑐 𝑁𝑓𝑢𝑒𝑙𝜎𝑓𝑢𝑒𝑙 𝑓 �̂� 𝑓 + 𝑁𝑎𝜎𝑎 𝑐 𝑁𝑓𝑢𝑒𝑙𝜎𝑓𝑢𝑒𝑙 𝑓 �̂� 𝑓 − 𝑘𝑐 𝐴𝑁𝑖 (10) materials and methods the type of msr proposed in this study is the conceptual design of icmsr (innovative compact molten salt reactor). icmsr is a power reactor with naf – thf4 – uf4 fuel. icmsr uses 19.75% uranium enrichment to avoid proliferation. the core of this reactor is a hetetype core, which is a heterogeneous graphite fuel and moderator layout, allowing molten salt to flow through many graphite blocks. the hetetype core design has the advantage that it requires the smallest initial fuel loading and the lowest radiotoxicity of the remaining spent fuel in long term operation [16]. in the icmsr design, the heat exchanger (he) is integrated with the core, the aim is to reduce fuel inventory in the core and reduce the size of the cooling system. icmsr is equipped with a noble and volatile gas extraction system. noble gases can be removed by purging an inert gas into the molten salt. with the extraction system, the utility of the neutron is higher because neutron poisons such as xe-135 no longer exist. higher neutron utility means more collisions with uranium-235, resulting in higher production of fission products such as mo-99. icmsr parameter and geometry is show in table 1 and figure 1. table 1. input parameter of icmsr parameter value (unit) power 75 mwe; 187.5 mwth temperature (during operation) 900k fuel naf-thf4-uf4 u-235 enrichment 19.75% core diameter; high 220 cm; 246 cm moderator graphite moderator diameter; high 28 cm; 150 cm intermediate coolant naf-kf vessel reactor hastelloy-n vessel diameter; high 400 cm; 10.51 m 109 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 figure 1. configuration of modular icmsr system the fuel depletion analysis was carried out for 12 days. the scenario of fuel depletion by removing gas fission products is carried out with the omit command. the analysis will only carried out at a power of 75 mwe (thermodynamic efficiency = 40%) where this value corresponds to the operating power of the icmsr. although in this reactor operation all data on isotope depletion information is available, this paper will only focus on the production of mo-99. the flowchart of this study is shown in figure 2. figure 2. flowchart of the study 110 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 the method used for calculation of the mo-99 isotope is a computation method. this study has used mcnp6. the mcnp (monte carlo n particle) is a computer program that developed since 1963 at los alamos national laboratory (lanl), united states. mcnp6 is the latest version of mcnp which has been successfully developed by lanl. mcnp6 is the result of merging mcnp5 and mcnpx into a single computer code program that contains the features of both. in addition, mcnp6 also includes new calculation capabilities such as calculation of reactor kinetic parameters, unstructured tally fmesh, and sensitivity analysis card [21]. the monte carlo method is a calculation method that theoretically imitates a statistical or random process. this method is usually used to solve complex problems, which can no longer be solved by deterministic calculation methods. this method is implemented by simulating every single probabilistic event that occurs in a process, one by one in sequence. the probability distribution that occurs in each event is calculated randomly. in this method, it takes a lot of repetition, so that the whole phenomenon being simulated can be fully and realistically described. multiplication factor calculation in mcnp can be done with several estimators [22]: a. collision estimator 𝑘𝑒𝑓𝑓 𝐶 = 1 𝑁 𝛴𝑖 𝑊𝑖 [ 𝛴𝑘𝑓𝑘�̅�𝑘𝜎𝑓𝑘 𝛴𝑘𝑓𝑘𝜎𝑇𝑘 ] (11) where, 𝑖 is summed over all collision in a cycle where fission is possible; 𝑘 is summed over all nuclides of the material involved in the 𝑖𝑡ℎ collision; 𝜎𝑇𝑘 is total microscopic cross section; 𝜎𝑓𝑘 is microscopic fission cross section; �̅�𝑘 is average number of prompt or total neutrons produced per fission by the collision nuclide at the incident energy; 𝑓𝑘 is atomic fraction for nuclide k; n is nominal source size for cycle; 𝑊𝑖 is weight of particle entering collision. b. absorption estimator 𝑘𝑒𝑓𝑓 𝐴 = 1 𝑁 𝛴𝑖 𝑊𝑖 �̅�𝑘 𝜎𝑓𝑘 𝜎𝑐𝑘+ 𝜎𝑓𝑘 (12) where, 𝑖 is summed over each analog absorption event in the 𝑘𝑡ℎ nuclide. c. track length estimators 𝑘𝑒𝑓𝑓 𝑇𝐿 = 1 𝑁 𝛴𝑖 𝑊𝑖 𝜌 𝑑 𝛴𝑘 𝑓𝑘 �̅�𝑘 𝜎𝑓𝑘 (13) where; 𝑖 is summed over all neutron trajectories; 𝜌 is atomic density in the cell; 𝑑 is the trajectory track length from the last event. the combination average of the three estimators is: 𝑘𝑒𝑓𝑓 𝑏𝑒𝑠𝑡 = ∑ 𝑘𝑒𝑓𝑓 𝑖 ∗𝑖,𝑖≠𝑗≠𝑘 (𝐶𝑗𝑗∗𝐶𝑘𝑘−𝐶𝑗𝑗∗𝐶𝑖𝑘−𝐶𝑘𝑘∗𝐶𝑖𝑗+𝐶𝑗𝑘∗(𝐶𝑖𝑗+𝐶𝑖𝑘−𝐶𝑗𝑘)) ∑ 𝐶𝑗𝑗∗𝐶𝑘𝑘−𝐶𝑗𝑗∗𝐶𝑖𝑘−𝐶𝑘𝑘∗𝐶𝑖𝑗+𝐶𝑗𝑘∗(𝐶𝑖𝑗+𝐶𝑖𝑘−𝐶𝑗𝑘)𝑖,𝑖≠𝑗≠𝑘 (14) where: 𝑖 = c, a, and tl 111 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 𝐶𝑖𝑗 = covariance = 1 𝑀 ∑ 𝑘𝑒𝑓𝑓𝑚 𝑖 𝑘𝑒𝑓𝑓𝑚 𝑗 − ( 1 𝑀 ∑ 𝑘𝑒𝑓𝑓𝑚 𝑖 𝑚 ) ( 1 𝑀 ∑ 𝑘𝑒𝑓𝑓𝑚 𝑗 𝑚 )𝑚 m is the index for the mth active cycle and m is the number of active cycles. results and discussion the burnup calculation with the extraction of noble gas for 12 days has been done. the results showed that during 12 days of operation, the reactor was still in critical condition. this indicates that there is no need to add fuel online at that time. this condition can be achieved with a mole fraction of uf4 of 5.6% with an enrichment of 19.75%. basically, the higher the two values, the higher the criticality value. but keep in mind, that the reactor will be safe when the criticality value is 1 or the reactivity value is zero and continues to be rated constant. the results show that keff value is slightly above 1. this supercritical condition is still relatively reasonable where the excess reactivity can be used to increase power if necessary. the results of the criticality value during operation can be seen in figure 3. figure 3. the criticality levels per day of icmsr reactor operation mo-99 is one of the major radionuclides in fps. table 2 shows the accumulation of mo-99 in the icmsr for 12 days. on day 0, mo-99 has not yet formed; meaning there is only fuel in the reactor core. the highest increase in mo-99 production was on the first day at 2.136 x 106 ci. this production is the result of the fission of fuels. on six days, the resulting average is around 1.245 x 106 ci, while on the 6th to 12th day the average generated is 0.275 x 106 ci. the total mo-99 produced until the 12th day is 9.118 x 106 ci. in icmsr, mo-99 can be extracted during power reactor operation through fission product extraction. so it is very profitable from an economic point of view. 112 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 table 2. specific production of mo-99 as by product of icmsr power reactor day specific production (ci) day specific production (ci) 1 2.136 x 106 7 7.946 x 106 2 3.794 x 106 8 8.306 x 106 3 5.083 x 106 9 8.597 x 106 4 6.085 x 106 10 8.822 x 106 5 6.863 x 106 11 8.893 x 106 6 7.472 x 106 12 9.118 x 106 conclusions the criticality of the icmsr reactor for 12 days of operation shows the rector is still in a critical condition so that there will be no intervention for refueling or power if mo-99 extraction is carried out in that time span. mo-99 production for six days of operation showed a high average of 1.245 x 106 ci. meanwhile, on the 6th to 12th day the average generated is 0.275 x 106 ci. the total mo99 produced until the 12th day is 9.118 x 106 ci. so it can be state that the icmsr power reactor produces an isotope that is useful for medical purposes, namely mo-99 as a by product. references [1] iaea, 1999, production technologies for molybdenum-99 and technetium-99m, iaea-tecdoc-1605. [2] m. r. a. pillai, a. dash, and f. f. r. k. jr, 2015, diversification of 99mo/99mtc separation: non-fission reactor production of 99mo as a strategy for enhancing 99mtc availability, j nucl med, 56 (1), 159-161. [3] iaea, 2015, feasibility of producing molybdenum-99 on a small scale using fission of low enriched uranium or neutron activation of natural molybdenum, technical report series no. 478, sti/doc/010/478 isbn 978-92-0-114713-4. [4] i. n. goldman, n. ramamoorthy, and p, 2008, presented at rertr int. meet. [5] wna, 2013, radioisotopes in medicine. [6] m. m. khalil, 2011, basic sciences of nuclear medicine, springer, united kingdom [7] j. j. p. de lima, 2011, nuclear medicine physics, taylor and francis group, us [8] s. cherry, j. sorenson, and m. phelps, 2012, physics in nuclear medicine, elsevier, amsterdam, netherlands [9] g. s. thomas and j. maddahi, 2010, the technetium shortage, j nucl cardiol, 17 (6), 993 – 998. [10] t. j. ruth, 2014, the medical isotope crisis: how we got here and where we are going, journal of nuclear medicine technology, 42 (4), 245 – 248. [11] y. nagai, and y. hatsukawa, 2009, production of 99mo for nuclear medicine by 100mo (n, 2n)99mo, journal of the physical society of japan, 78 (3). 113 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 105-113 eissn : 2747-173x submitted : june 29, 2022 accepted : september 8, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.32069 [12] syarip, t. sutondo, e. t. budisantoso, and e. susiantini, 2018, design and development of subcritical reactor by using aqueous fuel for 99mo production, a. physical and computational sciences, 55 (1), 21 -26. [13] s. kuntjoro, 2016, analysis of mo-99 isotope activation in the rsg-gas reactor (in indonesian), sigma epsilon, 20, 13 -20. [14] m. i. w. farezza, and syarip, 2018, mo-99 isotope production calculation of samop reactor experimental facility, international conference on computation in science and engineering. [15] d. bartolomeus and s. syarip, 2019, analysis of mo-99 production as function of camolyp reactor power, 4th padjajaran international physics symposium. [16] r. j. sheu, c. c. chao, o. feynberg, amd y. w. h. liu, 2014, a fuel depletion analysis of the msre and three conceptual small molten-salt reactors for mo-99 production, annals of nuclear energy, 71. [17] m. n. stoddart, j. n. harb, and m. j. memmott, 2019, numerical analysis of isotope production in molten salt reactors: a case study for molybdenum-99 production, annals of nuclear energy, 129, 56 – 61. [18] d. a. pakholik, o. y. kochnov, v. v. kolesov, and v. v. fomichev, 2021, increasing the production of the mo-99 isotope by modernizing the design of targets irradiated in the experimental channels of the vvr-c reactor, nuclear energy and technology, 7 (4), 291 – 295. [19] w. grimes, 1970, molten-salt reactor chemistry, nucl apply techn, 8 (2), 137 – 155. [20] d. y. chuvilin and v. a. zafryadskii, 2009, new method of producing 99mo in molten salt fluoride fuel, atomic energy, 107 (3), 185 – 193. [21] c. j. werner, j. armstrong, f. b. brown, j. s. bull, l. casswell, l. j. cox,…, b. c. kiedrowski, 2017, mcnp user’s manual code version 6.2, los alamos national laboratory, 746. [22] x-5 monte carlo team, 2008, mcnp-a general monte carlo n – particle transport code, version 5 volume i: overview and theory, los alamos national laboratory. 133 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 a brief review on the electrical resistivity of aluminium alloy and its nanoparticles at low temperature inzamam khalid1,a 1department of physics, government college university, lahore aemail: inzamamkhalid16@gmail.com abstract. the objective of this review article is to study the resistivity of aluminium alloy at low temperatures. various articles have been thoroughly studied for this review. alloys that contain al as dominant metal are termed as al alloys. the first conventional al alloy was prepared a6160 whose major constituents are si and mg. al metal in its pure form has very high electrical conductivity but it is soft. foils and conductor cables are made of al. for advanced applications, al is alloyed. the review has briefly explained the physical background of electrical resistivity and analysis of chosen material, aluminium alloy. furthermore it has also discussed the resistivity of nanoparticles of aluminium alloy. keywords: aluminium alloys, electrical resistivity, temperature, impurity 1. introduction materials behaviour is mainly characterised by the nature of their constituents. the evolved physical and nonphysical features are then attributed to the components and vary by external factors such as pressure and temperature, in general. specified electrical properties also depend upon the structure of the material. due to that, conducting, with low resistivity, materials are used to supply electric current to long resistance. while in some cases materials with high resistivity applied in different appliances e.g. electric heater, iron filament, etc. electrical and electronic systems use electrical resistance as the key parameter for the selection of materials. the right selection of material is based upon the required application. power distribution systems rely on electrical resistivity to assess transmission lines, earth grounding, and soil material. electrical resistivity is a manipulating variable function of temperature. electrical resistivity can be measured by using various methods and models. the shape of the sample and contact resistance defines which method is suitable for precision measurements. the resistivity of high resistive samples can be measured by using two probes methods (ohm metre or voltmeter – ammeter measurements) [15]. four probes methods can be used for the measurement of resistivity of materials those who have low resistance and single crystals. the resistivity of the pellets and bulky samples can be measured by using montgomery, van der pauw, and smith techniques. these are conventional techniques by which resistivity can be measured but other techniques which use modern technology analyse the resistivity. electrical resistivity is essential for the applications of metals, alloys and their nanoparticles, and a thorough understanding of their electrical resistivity is much needed. in many electrical applications we utilise in our daily lives, the electrical behaviour of a material can be as, and sometimes more, important than the mechanical properties. the electrical resistivity of aluminium alloy is of great practical importance especially in applications involving aerospace, automotive, architectural, lithographic, electric, and electronic applications. mailto:inzamamkhalid16@gmail.com 134 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 2. electrical resistivity of aluminium alloy at low temperature the resistivity of aluminium alloy varies from 0.5-6 μω cm as a function of temperature. but it was noticed by c. h. yin and l. m. qiu that variation in resistivity is infinitesimally small below 77k temperature [1]. at very low temperatures, especially lower than 20 k resistivity becomes nearly constant of al alloys. the resistance of different aluminium alloys at low temperature (ranges from ice point to helium temperature) will be (0.18-2.16)×10-3 with sample size 5 × 0.5 × 90 (𝑤𝑖𝑑𝑡ℎ × 𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 × 𝑙𝑒𝑛𝑔𝑡ℎ). the resistivity of aluminium alloys at low temperatures is 1000 times more than pure aluminium [2]. theoretical analysis shows that the cryocooler instrument can be used to study electrical resistivity below 38 k temperature [1]. to achieve a low-temperature environment two-stage cooler is used. by providing constant current the voltage is measured with variation in temperature. figure 1. resistance vs temperature of the cryocooler measurement platform [1]. as the debye temperature of aluminium is 380 k which concludes that its resistance below 38k nearly constant which can be shown in figure 1. above 90 k resistance is nearly proportional to temperature. the results can be compared with the physical property measurement system (ppms) system’s results to prove that they are accurate and reliable. experimental verification of the cryocooler measurement method is performed which shows only 1 %. the resistance of the aluminium alloy is nearly constant between 38 k and 4.20 k which was proposed theoretically and proved experimentally by c. h. yin and l. m. qiu[1]. this experiment also gives convenience that if the experimental setup does not allow 4.2 k temperature, for the measurement of resistivity of materials with low-value residual resistivity ratio or residual resistance ratio (rrr) (rrr<10), we can use any temperature between 38 k and 4.20 k. r. krsnik (r.k.) and e. babic (e.b.) measured the resistivity of aluminium alloys within the temperature range 4.2-100 k. by using rapid quenching techniques they obtained samples 135 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 covering a wide range of concentrations. r.k and e.b proved experimentally that resistivity of impurity is one greater than the highest found. they also founded from these observations that 𝜌𝑝ℎ ∝ 𝑇 3 so mainly resistivity depends upon impurities in this range [4]. there are more than ten different mechanisms by which we can observe deviation from the conventional resistivity proposed by matheissen (total resistivity is the sum of resistivity due to pure host (phonon) and resistivity due to impurity concentrations as well) [5]. we can study and specify some mechanism to eliminate the error factor in deviation from matthiessen's rule (dmr) by alloying al metal with different alloying elements and different concentrations. there is an ideology behind the anomalous impurity resistivity which says that interferences of phonon and impurity scattering at different temperatures cause deviation from standard impurity scattering values. aluminium is best for understanding dmr and anomalous impurity resistivity. caplina.d. and rizzutoc founded that al alloys with non-anomalous impurities resistivity at low temperature is given as, 𝜌(𝑇) = 𝜌0 + 𝜌𝑝𝑢𝑟𝑒 (𝑇) + 𝐴(𝜌0) 𝑇 3 (1) where,𝜌0is residual resistivity and 𝐴(𝜌0) is a varying function independent of the impurity. there are two theoretical ways by which equation (1) can be defended: one based on “extra electronphonon scattering processes due to impurities” while the second one “assumes that the impurities are the relaxation time over the fermi surface” [6]. to minimize the discrepancy between these two models it would be good to modify recent measurements to higher concentration and very low temperature. although the solid solubility of elements in aluminium is very high, increasing the concentration is difficult due to the formation of guinier preston zones (nanosized coherent pre-precipitates or solute clusters formed during natural ageing and in the early stages of artificial ageing). so the ultrarapid quenching technique is used to prepare high impurity concentration samples and the molten temperature of sample alloys can be varied. the samples prepared by r.k. and e.b. were thin strips having 20-50 μm thickness, 2 − 4 𝑚𝑚 broadness, and 3 − 5 𝑐𝑚long. concentrations can be determined with electron microscope analysis and the geometrical factor can be estimated from mass, length, and parameter of the lattice of the samples and via residual resistivity ratio. resistivity can be measured with the help of potentiometric setup with high accuracy up to 10-5. r.k. and e.b. concluded that there is no variation in impurity resistivity due to variation in temperature a few kelvin less than the temperature at which resistivity due thermal agitation is detectable. they also noted that different alloys with different residual resistivity showed the same behaviour during the increase in temperature. temperature dependence is always t3 at low temperature and above 200k resistivity increases faster same as ρpure(t) but in case of most concentrated alloys where phonon contribution is completely masked by t3dependence have the same dependence on t3. these results are according to the prescribed theoretical models (the first model predicts t3 dependence at low temperature and the second predicts t3 dependence only at an intermediate temperature and t5 dependence at very low temperature but r.k. and e.b. did not extend their measurement for t5 dependence rather only take measurements for the dependence of t3). to distinguish between these two models we have to consider the dependence of phonon resistivity on residual resistivity [4]. 136 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 figure 2. dependence of phonon resistivity ρ(t)ρ0 on impurity resistivity at three fixed temperatures. data is taken from senoussi and campbell [7] measurements and r.k and e.b. measurements. although the sample preparation technique was different from r.k and e.b their measurements have good agreement with senoussi and campbell measurements. consequently, they showed that the determination of dmr can get with using concentrated alloys and resistivities of these samples proportional to t3 up to 0.1 θd (debye temperature) which depends only log ρ0 the rapid quenching technique is best for the preparation of samples. over a wide range of annealing temperature variation in resistivity is measured during the ageing of aluminium alloy [8]. they took measurements by using a new approach and proposing solubility products for the q phase in aluminium and identified the contribution to overall resistivity due to precipitates. for studying precipitation in aluminium alloy, an electrical resistivity is a good tool but it is very hard to separate effects due to solute atoms and fine-scale precipitates. when precipitation starts, resistivity increases due to the formation of the solute cluster and keeps growing as precipitants increase. the methodology is also used for the separation of solute from solid solution and is known as resistivity anomaly. resistivity increases as the function of ageing times and becomes maximum for very long ageing time and then decreases to values below asquenched resistivity. the effect of ageing can be resolved by distinguishing between resistivity due to solute atoms (described by matthiessen’s rule) and resistivity due to fine-scale precipitates [9]. none theoretical model (e.g. increment in resistivity is due to strong scattering from clusters of solute atoms and reduction in resistivity is due to either increase in cluster’s radius more than the mean free path of electrons [9] or to the increasing anisotropy of bragg scattering from clusters ρ0 ρ(t)ρ0 137 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 [11]) could explain anomaly resistivity successfully so experimental calibration is required. uncertainty in resistivity is due to short quantitative analysis (it is considered that at early stages precipitation is very important while on the other hand effect of precipitates can be ignored when the spacing between clusters is larger than the mean free path of electrons and when spacing is the intermediate effect of a precipitate is less clear). for the determination of q phase product solubility and contribution of precipitate resistivity alloy solution prepared and treated at 560 0c, quenched in water, and for immediate ageing treated with temperature in a range of 200-560 0c for 1 h. to avoid temperature effects all the measurements were taken by immersing specimens in liquid nitrogen (77 k). measurements elaborated that initially resistivity increases with increasing ageing temperature and after 350 0 c the process is reversed and a plateau in resistivity is gained at 300 0c (plateau resistivity increases with temperature). so resistivity will not be affected by precipitates at higher temperatures (due to coarse structure) and the value of plateau resistivity represents the equilibrium condition. while for low-temperature precipitate resistivity is taken into account because plateau resistivity is not gained. so matthiessen’s rule can be moulded according to the above analysis as, 𝜌 = 𝜌𝑝𝑢𝑟𝑒 (𝑇) + ∑𝑖 𝜌𝑖 𝐶𝑖 + 𝜌𝑝𝑝𝑡 (2) where ρpure(t) is phonon resistivity due to thermal agitation, ρi is resistivity due to specific solute atoms and ci concentration of specific solute, and ρppt resistivity due to the formation of clusters. from plateau resistivity concentrations of precipitates can be measured and by using these concentration solubility products of q precipitate can be measured. figure 3. a comparison between experimental and equilibrium values [8] from figure 3 we can see that when the ageing temperature in the range of 450-560 0c the experimental and equilibrium values coincide but when decrement in temperature takes place 138 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 deviation of equilibrium values can be seen towards higher resistivities. the reason behind this deviation is due to the effect of precipitate resistivity and precipitate resistivity (depending on the separation between precipitates) can be calculated as, 𝜌𝑝𝑝𝑡 = 12 𝐿1/2 (3) where l is spacing between precipitates. table 1. the contribution of precipitate resistivity to the total resistivity varying with separation spacing between precipitates [8]. separation between precipitations contribution to total resistivity 10 nm 15-25 % 10-100 nm 10-15 % up to 1000 nm below 5 % in theoretical assumption, it is considered that scattering from precipitates, metastable precipitates, and solute clusters have similar behaviour but experimental observations show that precipitate resistivity must be taken into account especially for those precipitates which strengthen the alloys. consequently, it was found the effect on electrical resistivity due to different ageing temperatures of aluminium alloy and came to know that at higher temperatures resistivity due to precipitates can be ignored and lower temperatures of precipitates resistivity must be taken into account. according to these results, matthiessen’s rule can be modified which includes the term precipitate resistivity. by using this rule, the range of precipitate can be identified (where it is effective and where it is not). aluminium alloy with different heat treatment conditions shows that resistivity decreases uniformly within the temperature range liquid helium to ice point[12]. resistivity measurements of these alloys can be used to correlate with their other properties e.g. electrical conductivity, precipitation hardening, etc. the relation between electrical resistivity and electrical conductivity (λe) is given by the lorentz ratio. 𝐿 = 𝜌 𝜆𝑒 𝑇 (4) where l is the lorentz number. uncertainty in the measurements of aluminium is 0.4% which arises due to systematic error as well as two voltage measurements rather imprecision in the size of sample and voltage measurements because these errors are much less than systematic error. for these measurements, the electrical resistivity dip probe method can be used and for numerical calculations, a simple formula can be useful. 139 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 𝜌 = 𝐸 𝐼 × 𝐴 𝐿 = 𝑅𝑠 𝐴 𝐿 (5) graphical analysis of these measurements can be useful to show their behaviour according to change in temperature as well as heat tempering. figure 4. electrical resistivity of aluminium alloys [12]. the figure shows that alloys behave similarly with variation in temperature regardless of composition and heat treatment. so curve plots from room temperature measurements can be extrapolated to check the low-temperature behaviour of these or new aluminium alloys. except al 5083 and al 2024, which have larger and smaller resistivities respectively corresponding to larger and smaller content of impurity, there is also a rise in resistivity of alloy and alloy scales with a rise in impurity content [12]. heat treatment may change the phase structure of the specimen and can be done in four different ways (‘o’, t4, t6, and t86). the ‘o’ is the condition of heated alloy and cools slowly to form large precipitates that will separate; thus scattering is reduced. the ‘t4’ condition is naturally aged heated solid solutions while ‘t6’ is aged artificially so fine-scale precipitates will form to lower the resistivity. the final one is ‘t86’in which solution anneal and cold working is done during artificial ageing and resistivity increase due to imperfections (due to cold working). 3. resistivity of nanoparticles of al alloy the introduction of nanoparticles in the matrix influences the electrical, magnetical, optical as well as mechanical properties. aluminium alloy and nanoparticles introduced into them have specific characteristics e.g. high electrical resistivity, heat resistance, yield strength, plasticity, hardness, etc20. it has been found that if the grain size of the doped nanoparticles sample is much smaller 140 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 than the original one than electrical resistivity will increase because there would greater number of grains consequently there would be large grain boundary to hinder the charge carrier and reverse phenomenon will occur when grain size of sample embedded with nanoparticles is significantly larger than the original sample. smaller grain size also reduces the surface contact area between grains due to which motion of charge carriers reduces and resistivity will increase21. but it was found in [13] that grain size of 6061 alloy increases from (155 μm to 240 μm for wt. 0.5 %) when nanoparticles of alumina are introduced. so resistivity will decrease according to [14]. but increment in the consecration of nanoparticles causes a decrease in the grain size consequently resistivity increases. change in the cooling rate of the alloy will change the size of grains. figure 5. relations of resistivity with concentration and temperature of nanoparticles [15] the figure shows that when concentration increases the inverse of electrical resistivity increases and similar behaviour has shown by temperature increment. the decrease in resistivity with increasing temperature symbolises the semiconductor behaviour. when temperature increases the drift mobility of charge carriers increases due to thermal effects consequently resistivity will increase. basically in nanomaterials, there is little probability of overlapping the wave function of electrons of ions located at an adjacent site. but probability will increase when the temperature increases because ions vibrate more violently and transfer their electrons with each other as the resulting resistivity will decrease. 4. conclusion the present review revealed that the resistivity of al alloy is at low temperatures and is dependent upon temperature. at very low temperature (below 20 k) it is proportional to t5 and at low temperature (above 20 k and below 12th part of debye temperature) resistivity is proportional to t3 and resistivity has linear relation at high temperature (this is experimental verification of blochgruneisen theoretical calculations). from the behaviour of al alloy, we demonstrate that residual 141 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 133-141 eissn : 2747-173x submitted : august 19, 2022 accepted : november 10, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.33637 resistivity is nearly constant at any temperature. we prove that if any metal is in the pure form its resistivity becomes zero at absolute zero temperature and if the metal is impure resistivity becomes constant at specific temperatures (called residual resistivity). furthermore it has also been scientifically proven that resistivity of nanoparticles of aluminium increases with the increase in temperature references [1] c. h. yin, z. h. gan, s. h. wang, d. l. liu and l. m. qiu, "the measurement of rrr and resistance for aluminum alloy based on a cryocooler," cryocoolers, vol. 19, pp. 605-612, 2016. [2] clark, a.f, childs, g.e, wallace, g.h, “electrical resistivity of some engineering alloys at low temperatures,” cryogenics, vol. 456, pp. 295-305, 1970. [3] qiu, l.m, zhang, k.h, dong, w.q, et al, “study of mass flow distribution between stages in a two stage pulse tube cryocooler capable of 1.1 w at 4.2 k,” international journal of refrigeration, vol. 35(8), pp. 2332-2338, 2012. [4] r. krsnik, e. babic and c. rizzuto, “phonon resistivity in concentrated aluminum alloys,” solid state communications, vol. 12, pp.891—895, 1973. [5] jack bass “deviations from matthiessen's rule,” advances in physics, vol. 21,pp. 431604, 1972. [6] t. fujita, t. ohtsuka, “transport properties of cold-worked aluminum at low temperatures,” journal of low temperature physics, vol.29, pp.333–344, 1977. [7] a. fert, “transport in magnetic alloys: scattering asymmetries (anisotropic scattering, skew scattering, side-jump)” physica b+c, volumes 86–88, part 1, pp. 491-500, 1977. [8] raeisinia, babak & poole, warren & lloyd, d., “examination of precipitation in the aluminum alloy aa6111 using electrical resistivity measurements,” materials science and engineering a, vol. 420, pp. 245–249, 2006. [9] c. panseri, t. federighi, “interpretation of quench-sensitivity in al-zn-mg-cu alloys,”metallurgical transactions, vol. 94, pp. 99-107,1973. [10] p.l. rossiter, p. wells, “the dependence of electrical resistivity on short-range order,” j. phys., vol. 4, pp. 354–363,1966. [11] a.j. hillel, j.t. edwards, p. wilkes, “examination of precipitation in the aluminum alloy aa6111 using electrical resistivity measurements,” phil. mag, vol. 32, pp. 189–209,1975. [12] a. f. clark, g. e. childs, and g. h. wallace, “electrical resistivity of some engineering alloys at low temperatures,” cryogenics, vol. 8, pp.182-183,1970. [13] j. j. dick and d. l. styris, "electrical resistivity of silver foils under uniaxial shock-wave compression," j. appl. phys, vol. 4, pp. 1602-1617, 1975. [14] vladimir valikhov, nikolay kahidz, anton khrustalyov, ilya zhukov and alexander vorozhtsov, “investigation of structure, mechanical properties and crystallization of aluminum alloys containing aluminum oxide nanoparticles,” matec web of conferences, vol. 9, pp. 65-76, 2018. [15] yadunath singh, “electrical resistivity measurements: a review,” international journal of modern physics: conference series vol. 22 (2013) 745–756 https://www.sciencedirect.com/science/article/abs/pii/0378436377903989#! https://www.sciencedirect.com/science/journal/03784363 https://www.sciencedirect.com/science/journal/03784363/86/part/p1 https://link.springer.com/journal/11663 142 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 photo electrochemically manufactured hgo/cu2o monolayer with augmented photovoltaic features m. abdurrahman1,a, f.w burari2, and o.w olasoji2 1department of physics, faculty of natural science, federal university dutse, jigawa state, nigeria 2department of physics, faculty of natural science, abubakar tafawa balewa university, bauchi state, nigeria aemail: msabdurrahman@yahoo.com abstract. this writing report acquaint the chances for promoting efficiency betterment of p-cu2o electrode for pecs likewise in production of hydrogen gas, using hgo/cu2o hetero-structure. the arrangement was accomplished by both bracing the surface of p-cu2o plate embattled through thermal oxidization of copper sheet and also acquiring low cost, effortless and low impairment engineering deposition for utilizing hgo as absorber layer. the altitudinous efficiency of 4.80% and open circuit voltage of 185mv were incurred in an hgo/cu2o hetero-structure pec solar cell commence with copper foil thickness (0.1mm) substrate for preparing the cu2o thin film under oxygen gas pressure at 950℃ by thermal oxidizing techniques. it is requisite to augmented the interface at the hetero-structure junction to accomplished a soaring efficiency in hgo/cu2o/hgo semiconductor beside multiplicative the parallel resistance and remittent the series resistance. keywords: thermal oxidation; cuprous oxide; hetero-structure; j-v characteristic, photoelectrochemical, annealing, etching 1. introduction sustainable rootage of energy for gleaning solar energy has for all time been a development subject field of interest, with greater than before focus in the research of hydrogen gas by photo electrochemically water-splitting at the photo cathodes [1] and p-type semiconducting material that can change over solar irradiation into electrical energy in photovoltaic cells[2,3]. the photovoltaic transition method is consisted of 3 three sequential steps: exhilaration of valency band by the negatron to conduction band by light assimilation when ray of light by photon free energies bigger than the band gap vigor of the photoactive stratum, as a consequence of the absorption yielding to establishment of excitations consisting of hole-electron pairs; disassociation of the excitations to emancipated carriers; and the carrying of carriers by the electrical field created at the hetero-interface[4,5]. therefore, the transition efficiency for solitary p-nheterojunction photovoltaic cells is intimately connected to the band gap free energy of the psemiconducting material, and the hypothetical transition efficiency is anticipated to be roughly 28% under the situation of being uncovered to solar radiation of am1.5 illumination (1 sun) [6]. to further the enlargement of the light-soaking up band, enhancing the transition efficiency, and improvement of quantum transition efficiency are compulsory, and it is promising strategy for acquainting two or more p-type semiconductors materials with dissimilar band gap free energies in a light engrossing stratum to get the better of the restriction of band gap free energy-originated hypothetical transition efficiency imposed on solitary photovoltaic cells[7], transition efficiency of 143 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 33.7% incontestable by a ingap/gaas/ingaas threefold-junction tandem photovoltaic cell [8] copper i oxide (cuo)[10] and copper ii oxides (cu2o)[9] are p-type semiconductors materials with the band gap free energies of 1.4 and 2.1ev, and both of them have the quality of being utilize as photovoltaic layers in oxide photovoltaic cells,[11-12] likewise as photocathode’s and to fabricate hydrogen natural gas by photoelectrochemical water ripping [13-14] in addition, pcu2o/pcuo monolayer live up to the aforesaid multi-band gap scheme to improve the performance and attracted escalating attention as photoactive stratums [15-17]. thermal oxidization of metallic copper foil had been embattled the cu2o and cuo layers by abundant techniques [18,19] gas-stage deposition procedures such as pulsed laser deposition and sputtering [20,21] and solution compound procedures which comprise of electrochemical procedures [22-23]. the cu2o/cuo monolayer have been embattled by numerous ways equanimous of chemical arrangements complied by heating system [24,25], and the enhanced photovoltaic and a cathode that emits electrons when well-lighted features have incontestable for those organized by the cu2o electro-deposition complied by concomitant thermal oxidization in air.[15,16] the cu2o/cuo monolayer’s displayed an extend solar cell wavelength compass uprising from both cuo and cu2o stratums, but the exterior quantum efficiency (eqe) was low down, equated to those for the solitary cuo and cu2o stratums [26,27]. the unveiling of nanopores into the copper ii oxide stratum and morphological modifying in the texture of the cuo stratum were conveyed onward by heating system, which pose damaging effects on the solar cell feature [15]. here, we account the manufacture of hgo/cu2o monolayer’s by two subsequent thermally oxidizing methods; for synthesis of cu2o from cu plate followed by annealing technique of cu2o layer in a furnace under vigorous oxygen condition, while for deposition of hgo was also deposited using thermally oxidizing method, the effect of hgo/cu2o stratum structure, optical and photovoltaic were investigated using ftir and i-v characteristic curves. 2.theoretical consideration a photoelectrochemical (pec) photovoltaic cell which occurred in both p-type and n-type semiconducting materials which composed of operational electrode and counter electrode; for ptype semiconducting material is composed of operational electrode which is cathode and the anode as the counter electrode, while in the case of n-type semiconductor electrodes will constitute the anode as the operational electrode and a cathode as a counter electrode. the two different electrodes are interrelated through an outer circuit. where between the electrodes a liquidness electrolytes is rendered to the photovoltaic cell, serving as a conducting intermediary. the operational electrode can be constituted of a semiconducting material, nanocrystalline or polycrystalline, which is usually affiliated to a conducting substratum. electric current will flow as soon as electrolyte brought into contact with an n-doped semiconducting material, and their equilibrium is earned when their electrochemical potentialities are equated. shut to the semiconducting material electrolyte boundary or interface the assimilation of a quantum of electromagnetic emanation with free energy exceptional the banding gaps bring forth hole-electron pairs. in instance of the touchstone redox potential (voredox) lies below fermi level (ef), the electrons will be reclusively from the semiconducting material to the electrolyte, leave-taking positive charges at the rear. when the holes reach out the surface and respond with a solution that comport electricity, charge dismemberment will take placed. the majority of the semiconducting material and prospective drop incurred amongst the surfaces 144 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 produce an electrical field, were disseminated in a charge polarized grade-constructed stratum (space charge layer) and represented by an alleged band bending, see figure 1 concerning the disengagement method of the photo yielded hole/electron pairs the electric field is significant. in the solution that convey electricity the charge ordering is frequently delineated in the terms of gouy-chapman layers and helmholtz [28], figure 1. graphical representation arrangement of a charge-polarized facade layer in pecs photovoltaic cell[29] 3.experimental procedure thermally oxidizing technique was pick out to produce the copper ii oxide thin film and hgo/cu2o hetero-structure. the working electrode was a piece of hgo/cu2o plate and the counter electrode was a piece of copper foil plate. the electrolyte comprised of 1g of nacl in 1 ml of sublimate water in a crystal clear cylinder. copper plate in sort of foil thickness 0.1mm after wounding into standard size wafers of 2cm×2cm were thermally oxidizing in a furnace, engraving in a washy nitric acid hno3, mantled up with paper for the purpose of smoothened the surface of the foil with aid of edge of beaker or bottle and finally dried with oven at 40-50℃ and hive away in a scavenge envelop prepared for soaring temperature oxidization. the sample was place in between ceramic crucible and placed inside a soaring temperature furnace at 950℃ which oxidized for 8 min and right away quenched in cold distilled water then dried by inserting them in between papers tissue then last but not least in air. annealing process was conducted in order to cure defect in the sample after the long temperature oxidization which carried at 500℃ inside the furnace quenched in sublimate water then finally in air followed by 145 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 chemical engraving process which was conducted in order to removed the unwanted black copper surface on top of the livered cuprous oxide using 4gm of fecl2, 4gm of nacl all in 100ml of sublimate water which act as the solvent, 2ml of hcl concentrated then the model was engrossed in all mention solvent shaken gently until the black colour completely engraved then dried in between tissue paper as a final point in air. another engraving in 8gm of potassium persulphate dissolved in 100ml of sublimate water, the appearing of livered colour feature of cu2o considered the complete engraving processes (see figure 2). figure 2. block illustration of the engraving process after the synthesis of the cu2o via the unalterable etching process we used the chemical vapour transport (cvt) figure 3 consist the mixed mercury oxide with transport agent (bromine br) in a given container were the oxygen inside the furnace as the chalcogen within an unseal vacuum. the unseal vacuum was placed in the clayware crucible and then arranged in a higher temperature furnace (700-1000℃), were a dynamical force within the unseal tube produced temperature gradient which help or excited the transport agent which lead to the deposition of hgo on the cu2o. figure 3. chemical vapour transport [29] testing the solar cell was conducted in a transparent container containing 1 mole of the electrolyte (nacl) copper wire electrode were made to the two electrode the working electrode (hgo/cu2o) cu2o cu2o cu2o cu2o cuo cuo cu cu 146 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 and for the counter electrode (cu) using ash grey paste and subsequently both placed within the container then to micro-ammeter for the rationale of perusing the i-v characteristic as demonstrated below in figure 4. figure 4. diagram of the made-up hgo/cu2o photoelectrochemical solar cell 4.result and discussion photo electrochemically manufactured hgo/cu2o monolayer’s and the solar cell features; figure 5 and 6 shows the curved thermally oxidizing hgo/cu2o and cu2o layers under the illumination which conduced to the deduction of photovoltaic parameters in table 1.0 below. as seen here the deposition of the hgo on the cu2o substrate drastic increase in the external solar cell parameters under illumination the efficiency increase from 0.474% to4.799% likewise the short circuit current with all other parameters are also been affected by the deposition. because light with photon free energies larger than the band gap free energy of hgo/cu2o layer constitute a considerably large portion of the sunlight induced the absorption of free energy and consequently cause excitation of electrons from the valence to conduction band in the hgo/cu2o layer which were then swept toward the solution by the electric field formed at the boundaries between the hgo/cu2o layer and the electrolyte solution. the increase in electric current and the voltage originated from the increase in minority carries of electrons within the electric circuit of hgo/cu2o-cu fabricated photovoltaic cell and the electrolyte. table 1. the photo voltage, efficiency, maximum power, and photocurrent of different readings of cu hgo/cu2o photoelectrochemical solar cell s/n 𝐼𝑆𝐶 𝑉𝑂𝐶 𝑃𝑀𝐴𝑋 𝜂 1 0.89ma 28mv 14.6× 10−4w 0.474% 2 3.28ma 185mv 153× 10−4w 4.799% µ a hgo/cu2ocathode cu anode electrolyte sunlight transparent plastic container 147 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 figure 5. the current-voltage features of synthesized cu2o before deposition hgo figure 6. the graph of current-voltage features of synthesized hgo/cu2o/hgo after deposition of hgo 148 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 figure 7. the ftir of deposited mercury oxide in a furnace on pinnacle of cu2o substrate figure 7.0 present the psychoanalysis of hgo/cu2o ftir. in the sample there are five 5 different huge peaks with more than 10 different small peaks detected or perceived from the sample when examining, expressing that the sample is not a simple structure but a complex structure; meaning that the deposited hgo stratum conjointly with the substrate cu2o composed of antithetical parts which are also tricky in examining them independently. appearance of some extremum at the single bond area notifying that there is single bond inside the model. disappearance of broad absorption band were hydrogen bond is located explicated that there is no hydrogen bond, visual aspect of sharp band in oxygen-related compound inside the examined model, wholesome the present of the cu2o substrate in the model. correspondingly hydroxyl compound extremum was also perceived at the range of substantiation of hydroxyl compound. no aromatic structure detected in the sample but there is c-c bond perceived at the model. also aldehyde extremum was found immediately after the aromatic peak boundary. no triple bond region in the sample responding to absence of c≡c triple bond. vinyl related compound accessible at the sample surface. no aromatic ring compound detected. a finger print region which is always discovered at the tail end or fag end of the ftir graph was also perceived were the whole nature and structure of the model are present. 4. conclusions soaring-efficiency p-type semiconducting material hetero-structure photovoltaic cells were manufactured by machinating hgo/cu2o/hgo thin film on cu2o sheet that had been organized by thermal oxidizing of copper foil sheet. the momentous betterment of photovoltaic belongings was accomplished by not merely bracing the surface of p-cu2o plate embattled through thermal oxidization of copper ii oxide but also acquiring low cost, effortless and low impairment engineering deposition for utilizing hgo as absorber. the procurable photovoltaic belongings in 149 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 hgo/cu2o/hgo semiconducting material hetero-structure solar cell are substantially more stagestruck by the experiment condition of the boundary at the hetero-structure. the soaring efficiency of 4.80% and open circuit voltage of 185mv were incurred in an hgo/cu2o-cu manufactured solar cell from the initial foil of thickness 0.1mm by two thermally oxidizing methods for preparing cu2o and for deposition of hgo on cu2o and quantitate under solar illumination. acknowledgements this work was supported by tetfund scholarship and i would like to thank federal university, dutse for providing suited environment for the research with free internet access during the research work. references [1] walter, m. g.; warren, e. l.; mckone, j. r.; boettcher, s. w.; mi, q.; santori, e. a.; lewis, (2010) n. s. solar water splitting cells. chem. rev. 110, 6446-6473. 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[7] yamaguchi, m.(2003) iii-v compound multi-junction solar cells: present and future. sol. energy mater. sol. cells, 75, 261-269. [8] takamoto, t.; kaneiwa, m.; imaizumi, m.; yamaguchi, m. (2005) ingap/gaas-based multijunction solar cells. prog. photovolt.: res. appl. 13, 495-511. [9] koffyberg, f. p.; benko, f. a.(1982) a photoelectrochemical determination of the position of the conduction and valence band edges of p-type cuo. j. appl. phys. 53, 1173-1177. [10] snoke, d. w.; shields, a. j.; cardona, m. (1992) phonon-absorption recombination luminescence of room-temperature excitons in cu2o. phys. rev. b: condens. matter mater. phys. 45, 11693-11697. [11] korottcenkov, g.(2018). the future of semiconductor oxides in nextgeneration solar cells, all oxide solar cells; elsevier: cambridge; pp 439-480. [12] khoo, p. l.; nagai, m.; watanabe, m.; izaki, m.(2018) electrodeposited cuo photovoltaic device with polysiloxane layer. j. surf. finish. soc. jpn. 69, 469-471. [13] li, c.; he, j.; xiao, y.; li, y.; delaunay, j.-j.(2020) earth-abundant cu-based metal oxide photocathodes for electrochemical water splitting. energy environ. sci. 13, 3269. 150 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 [14] masudy-panah, s.; moakhar, r. s.; chua, c. s.; kushwaha, a.; dalapati, g. k.(2017) stable and efficient cuo based photocathode throughoxygen-rich composition and au-pd nanostructure incorporation for solar hydrogen production. acs appl. mater. interfaces, 9, 27596-27606. [15] izaki, m.; fukazawa, k.; sato, k.; khoo, p. l.; kobayashi, m.; takeuchi, a.; uesugi, k.(2019) defect structure and photovoltaic characteristics of internally stacked cuo/cu2o photoactive layer prepared by electrodeposition and heating. acs appl. energy mater. 2, 4833-4840. [16] yang, y.; xu, d.; wu, q.; diao, p.(2016) cu2o/cuobilayered composite as a highefficiency photocathode for photoelectrochemical hydrogen evolution reaction. sci. rep. 6, 35158. [17] dubale, a. a.; ahmed, i. n.; zhang, y.-j.; yang, x.-l.; xie, m.h.(2020) a facile strategy for fabricating c@cu2o/cuo composite for efficient photochemical hydrogen production with high external quantum efficiency. appl. surf. sci. 534, 147582. [18] minami, t.; nishi, y.; miyata, t.(2016) efficiency enhancement using a zn1-xgexo thin film as an n-type window layer in cu2o-based heterojunction solar cells. apex 9, 052301. [19] wang, p.; zhao, x.; li, b.(2011) zno-coated cuo nanowire arrays: fabrications, optoelectronic properties, and photovoltaic applications. opt. exp. 19, 11271-11279. [20] paul, g. k.; nawa, y.; sato, h.; sakurai, t.; akimoto, k.(2006) defects in cu2o studied by deep level transient spectroscopy. appl. phys. lett. 88, 141901. [21] bhardwaj, r.; barman, r.; kaur, d.(2016) improved photovoltaic effect in cuo/zn1-xmgxo heterojunction solar cell by pulsed laser deposition. mater. lett. 185, 230-234. [22] mizuno, k.; izaki, m.; murase, k.; shinagawa, t.; chigane, m.; inaba, m.; tasaka, a.; awakura, y.(2005) structural and electrical characterizations of electrodeposited p-type semiconductor cu2o films. j. electrochem. soc. 152, c179-c182. [23] zimbovskii, d. s.; churagulov, b. r.(2018) cu2o and cuo films produced by chemical and anodic oxidation on the surface of copper foil. inorg. mater. 54, 660-666. [24] wijesundera, r. p.; hidaka, m.; koga, k.; choi, j.-y.; sung, n. e.(2010) structural and electronic properties of electrodeposited heterojunction of cuo/cu2o. ceramics 54, 19. [25] kim, a.-y.; kim, m. k.; cho, k.; woo, j.-y.; lee, y.; han, s.h.; byun, d.; choi, w.; lee, j. k.(2016) one-step catalytic synthesis of cuo/cu2o in a graphitized porous c matric derived from the cubased metal-organic framework for liand na-ion batteries. acs appl. mater. interfaces 8, 19514-19523. [26] khoo, p. l.; kikkawa, y.; satou, k.; shinagawa, t.; izaki, m.(2018) improvements in external quantum efficiency of electrochemically constructed n-zno/p-cu2o photovoltaic devices by rapid thermal annealing. thin solid films 653, 158-164. [27] kaphle, a.; echeverria, e.; mcllroy, d. n.; hari, p.(2020) enhancement in the performance of nanostructured cuo-zno solar cells by band alignment. rsc adv. 10, 7839-7853. [28] a. j. bard, l. r.(1995) faulkner, electrochem. methods: fundamental and application, vhc, new york, usa [29] m. abdurrahman, f.w burari, & o.w olasoji. analysis of the zno/cu2o and cdse/cu2o thin film hetero-structure electrode for photo electrochemical solar cell applications. 151 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 142-151 eissn : 2747-173x submitted : june 22, 2022 accepted : october 28, 2022 online : november 11, 2022 doi : 10.19184/cerimre.v5i2.31858 international journal of advances in scientific research and engineering (ijasre).e-issn :2454-8006 doi: 10.31695/ijasre.2022.8.4.10 78 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 optical ray tracing simulation by using monte carlo method for reflectance-based photoplethysmography sensor in human skin and fingertip model muhamad affiq bin misran1,a, anubha bilgaiyan2, and reiji hattori1,3 1department of applied science for electronics and materials, kyushu university, japan 2innovation center for organic electronics, yamagata university, japan 3global innovation center (gic), kyushu university, japan aemail: misran.muhamad.458@s.kyushu-u.ac.jp abstract. the pulse oximetry device has been used for decades to monitor human pulse rate and oxygen saturation. there are two types of pulse oximetry which are transmission and reflection based. however, most devices are unsuitable for daily health monitoring due to the bulkiness and inconvenience of longterm monitoring while continuously doing everyday activities. therefore, developing a wearable device such as a patch would benefit the users. several factors can be considered for such a system. one of them is the distance between the source and detector since both are the major components of this system. however, there is still a lack of information in this regard. this study used the ray-tracing monte carlo method to simulate transmittance and reflectance-based oximetry principles with a 663 nm wavelength as the light source. the results show the ray tracing behavior from the light source to the photodetector in the biological tissue under two different structures mentioned previously. the separation between the light source and the detector should be less than 3 mm for the reflection type. a significant difference was observed for a distance greater than 3 mm compared with the transmission-based, which has a higher photocurrent even at a 7 mm distance. however, this transmission-based device is limited to the placement of the device on the body part. it is due to the thickness, which varies depending on the body parts themselves. therefore, wearable pulse oximetry devices with the reflectance-based principle are better due to higher signal acquisition than the transmittance-based, especially for the daily health monitoring system. furthermore, it also can be used throughout any body part. this reflection-based device can fully utilize microfabrication to integrate the light source and photodetector. keywords: ppg sensor, monte carlo, tissue optics, pulse oximetry, photoplethysmography introduction the pulse oximeter is a device that uses a non-invasive technique to monitor oxygen saturation in the blood as an initial procedure before further diagnosing can be performed on a patient [1]. then, the information from the device is used to appraise the numerous medical conditions related to the behavior of the heart and lungs [2]. in general, pulse oximetry operates in two principles, as shown in figure 1. the principles are reflection-based and transmission-based, which can be easily purchased from the market. the pulse oximeter devices comprise two major components. those components are the light source and the photodetector. the emitted light from the light source is propagated in the skin, blood, bone, and other tissues in different conditions, such as absorbed, transmitted, scattered, 79 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 and partially reflected. then, the photodetector is used to sense the reflected light (reflectionbased) or different the different intensities (transmission-based), where it generates the electrical signal [3]. this electrical signal consists of two pieces of information: the ac pulsatile and the quasi-static dc components [4]. these components make the photoplethysmography (ppg) signal, as shown in figure 2. from figure 2, the significant dc component corresponds to the light diffusion through the tissues, venous blood, static arterial blood, and skin. in contrast, the small ac signal arises from the differences in light absorption in the arterial blood vessels during the systole and diastole pulsation [5]. the signal helps to provide some preliminary information about the user’s health condition since the pulsation (blood flow) itself is controlled by neural, cardiac, and respiratory interactions. figure 1. principle of (a) reflectance-based and (b) transmission-based pulse oximeters. figure 2. ppg signal components several studies have developed the pulse oximeter, especially in recent years, to improve its performance, reliability, and feasibility, mainly as wearable daily health monitoring devices. in 80 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 2014, huang et al. demonstrated the ring-type pulse oximeter with a multi-detector system [6]. in this system, the effect of the light source and detector placement at different angles was investigated and compared with multi-detectors method for measuring arterial oxygen saturation (spo2). they also indicated that using a multi-detector system can further enhance the ppg signal collection. a higher correlation was observed between their approach and the commercial fingertip-type pulse oximeter. a reflectance-based pulse meter sensor with a circular structure of organic light-emitting diode (oled) surrounded by the organic photodetector (opd) at two different distances was fabricated by elsamnah et al. in 2019 [7]. their finding shows that a shorter length has a higher signal-to-noise ratio (snr). therefore, the light source and photodetector placement can significantly affect the ppg signals. however, there is still a lack of information regarding the optical behavior in the finger structure or turbid media. it is due to the complexity of those structures and the optical characteristics which significantly impact the light scattering behavior in the human body. the optical human tissue simulation has been widely studied to understand light characteristics and behaviors in the turbid media. this study is crucial to improve the reliability of the devices or applications which use the light source and photodetector as their major components. in 1993, hiraoka et al. studied the optical path length using the monte carlo (mc) method at near-infrared (nir) in the homogeneous tissue [8]. reuss et al. also used this mc method in 2004 to investigate arterial pulsation based on the reflectance pulse oximetry on a tissue model [9]. in 2007, peris et al. established a custom mc method platform, generating the mechanism in pulse oximetry based on the opto-physiological model [10]. then, chatterjee et al. also analyzed the optical interactions in reflectance and transmittance finger ppg using the mc method in 2019 [11]. thus, studying the interaction between light and human skin is necessary to provide reliable and valuable information for further enhancing ppg devices. in this study, we used the lighttools software with the mc ray tracing method to perform this simulation. a skin model with only a reflectance-based approach was used to observe the ray tracing internally. then, a fingertip model was used to monitor the ray tracing based on the reflectance and transmittance principles. we tried to imitate the pulsation condition by changing the thickness of the highly oxygenated blood layer for the skin structure and the artery’s diameter for the fingertip structure. then, we estimated the optimum distance between the light source and detector for the pulse oximetry device. materials and methods the present study used the lighttools software with the mc method for the optical ray tracing for the optical simulation. the geometry and structure of models are discussed here. other information, such as the optical properties of the materials used in this simulation, also is explained here. geometry of the skin and finger structure the skin tissue model used in this simulation is shown in figure 3, comprising three main layers. the epidermis is the outer skin layer composed of dead cells as a protective layer. the dermis is a layer that acts as a cushion for the inner layer and consists of the plexus superficials and the plexus profundus layers. many blood capillaries exist in this layer, especially in the plexus profundus, where the pulsatile condition occurs. the bottom layer is the subcutaneous or 81 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 hypodermis layer, mainly composed of fat and other tissues. the construction of the skin model used in this simulation is summarized in table 1 [9,12-16]. figure 3. skin tissue model table 1. human skin model thicknesses layer sublayer thickness (mm) epidermis 0.2 dermis dermis 1st layer 0.2 plexus superficials 0.2 dermis 2nd layer 0.9 plexus profundus 0.6 hb 0.06 hbo2 0.012 (initial) 0.060 (pulsatile) subcutaneous tissue 4.0 the fingertip structure consists of muscles, bone, and tendons, where the size of each of them differs between individuals. therefore, there is no standard size for this model. the basic fingertip structure was considered for simplicity, as shown in figure 4, with the dimension used [6,17-19]. 82 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 figure 4. fingertip structure model optical simulation by monte carlo (mc) method the light is treated as a bundle of photons transported in the turbid media in the mc simulation. the trajectories of photons in the media are determined by the random numbers generated by a computer statistically and characterized by several optical parameters. the henyey-greenstein distribution is commonly used in biomedical optics, where it is applied in the lighttools software, and the function is given by [20]: 𝑝(𝜃) = 1 4𝜋 . 1−𝑔2 (1+𝑔2−2𝑔.𝑐𝑜𝑠(𝜃)) 3 2 (1) where θ is the scattering angle, and g is the scattering anisotropy parameter. the value of g is represented by the cosine of the scattering angle as given by [20]: 𝑔 ≡ 〈𝑐𝑜𝑠 𝜃〉 = ∫ 𝑝(𝜃) 𝜋 0 𝑐𝑜𝑠 𝜃 . 2𝜋 𝑠𝑖𝑛 𝜃𝑑𝜃. (2) several essential parameters for the optical human tissue simulation will determine the behavior of the light scattering and distribution in the human tissue. these optical properties are the refractive index (η), anisotropy parameter (g), absorption coefficient (µa), scattering coefficient (µs), and mean free path (mfp). these optical parameters are summarized in tables 2 and 3 [6,9,21,22]. table 2. optical properties for the human skin structure. material refractive index (η) anisotropy parameter (g) absorption coefficient (µa) in mm -1 scattering coefficient (µs) in mm -1 mfp in mm epidermis 1.433 0.79 0.27 10.7 0.093458 dermis 1.396 0.81 0.27 18.7 0.053476 dermis with 1.396 0.82 0.27 19.2 0.052083 83 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 plexus superficials dermis with plexus profundus 1.400 0.78 0.27 22.5 0.044444 hbo2 1.363 0.98 0.20 77.5 0.012900 hb 1.362 0.98 0.72 77.5 0.012800 subcutaneous tissue 1.370 0.75 0.003 5.0 0.20000 table 3. optical properties for the human fingertip structure. material refractive index (η) anisotropy parameter (g) absorption coefficient (µa) in mm -1 scattering coefficient (µs) in mm -1 mfp in mm epidermis 1.433 0.79 0.27 10.7 0.093458 dermis and pulp 1.380 0.91 0.05 8.6 0.115600 bone 1.400 0.92 0.05 33.1 0.030100 hbo2 1.363 0.98 0.20 77.5 0.012900 hb 1.362 0.98 0.72 77.5 0.012800 simulation process this simulation was performed on the fingertip structure based on both principles. however, only reflection-based was applied for the skin structure since the feasibility of the transmission-based pulse oximetry does not apply to the thicker area of human body parts such as the arm and forehead. figures 5 and 6 show the configuration between the light source and the detector placement used in these simulations. 84 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 figure 5. fingertip structure model figure 6. transmission (left) and reflection (right) type of the simulation setup these simulations used 633 nm (red light) wavelength at 1 mw radiometric power as the light source. it has surface illuminance and the lambertian characteristics for the light’s angular distribution. at the same time, the detector has surface detection to observe and measure the number of photons that arrive at the detector surface. the pulsatile condition was done by changing the structure thickness. the diastolic mode is assumed to be the initial condition, where it represents the dc component in the ppg signal. in systolic mode, the thickness or radius of hbo2 in both structures was increased based on table 1 and fig. 4. the difference is used to represent the ac component of the signal obtained from the simulation. 85 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 results and discussion ray tracing (skin and fingertip model) figure 7 shows the ray-tracing distribution under the scattering events in the skin model for the reflection-based principle. the distance between the light source and the detector was 0 mm, filtered by the light distributed only related to the hbo2 layer to the detector surface. in this simulation, we used 105 numbers of rays for visualization purposes only, as shown in fig. 7, whereas 108 numbers of rays for the data collection. most of the rays were scattered within the dermis layer due to a higher scattering coefficient than other components. figure 7. filtered ray tracing distribution of the hbo2 layer in the skin model we fixed the distance between the source and detector for the fingertip model at 7 mm for transmission and 0 mm for reflection-based principles. similar to the previous analysis, 105 numbers of rays were used for visualization purposes and 108 numbers of rays for data collection. for transmission-based structure, the distance was set to 7 mm by assuming the presence of a slight pressure applied onto the fingertip during the ppg measurement process, such as the cliptype ppg device. based on figure 8, the transmission-based principle shows a smaller number of rays arrived at the detector surface from the light source. one of the reasons is the long traveling path of the propagated light within the model. another reason is the bone structure’s high scattering effect, which hindered the light propagation. 86 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 (a) transmission-based with sectional view (left) and side view (right). (b) reflection-based with sectional view (left) and side view (right). figure 8. filtered ray tracing distribution of the hbo2 from the artery in the fingertip structure pulsating condition figure 9 shows the signal intensity (both dc and ac components) from the skin model based on the number of photons detected on the surface of the detector at a different distance between the light source and the sensor. it shows a similar pattern as shown in figure 2 previously, where the signal produced by the pulsating condition will increase as the hbo2 volume increase. it also shows that the number of photons reduced as the distance increased in the diastole and systole conditions. 87 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 figure 9. number of photons detected at the sensor surface for the diastole and systole conditions we further analyzed the signals obtained from the simulation by converting them into electrical signals. we can estimate the photocurrent produced at the sensor based on the performance of the photodetector, which we developed previously and explained in detail elsewhere [5,7]. the current density was calculated based on the assumption that the photodetector’s external quantum efficiency (eqe) is at 40%. the ac signals from the produced photocurrent at different distances between the source and detector are shown in figure 10. as we increased the distance, the calculated photocurrent density significantly changed. at 0 mm to 2 mm distances between the source and detector, the estimated photocurrent was slightly reduced but still within a similar order of magnitude, around 10-10 a/mm2. however, a significant photocurrent reduction was observed from 10-11 a/mm2 to 10-12 a/mm2 as we increased the distances from 3 mm to 5 mm. we suspected that it was due to the raised traveling path of the rays from the interest area as we increased the distance of the detector from the illuminated area. the scattering events in the turbid media are also an essential factor affecting the reflected light to the sensor. 88 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 figure 10. estimated photocurrent density for ac component from the skin model at different source-detector separation we also simulated both principles on the fingertip structure. the purpose was to observe the effect of the position or location between the source and detector. the photocurrent density for the reflection and transmission-based are shown in figure 11. as expected, the closer distance between the source and detector has higher photocurrent density even in the fingertip model for the reflection-based, similar to the simulated skin model results. however, it is slightly different in the case of distance from 1 mm to 3 mm for both models. a linear decrease in photocurrent density was observed in the skin model, shown previously in figure 10. since we are assuming the homogeneous layer for each element for the skin model, thus the reduction shows linearity. in contrast, a slightly increased photocurrent density was observed at a 2 mm distance for the fingertip model. even though the reason is still unknown, these photocurrent densities from 1 mm, 2 mm, and 3 mm distances were still within a similar order of magnitude at 10-12 a/mm2. as we increased the distance further to 4 mm and 5 mm, a significant reduction of the photocurrent density was observed at 10-14 a/mm2. in the case of the transmission-based, the photocurrent density was two orders higher than the reflection-based at 4 mm and 5 mm distance with 10-12 a/mm2. however, it is still lower than values for 0 mm to 3 mm distances. the position between the source and detector significantly impacts the sensing process. here, the bone structure between them is one of the main reasons for the lower photocurrent density detected. the bone itself has higher opacity than other elements in the model. thus, less light could penetrate the fingertip model and reach the sensor surface. 89 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 figure 11. estimated photocurrent density for ac component from the fingertip model at different source-detector separation for reflection and transmission-based conclusions the ray-tracing mc simulation was performed to study the optical interactions in the turbid media for designing the ppg sensor device. in this study, we investigated the effect of the distance between the light source and detector, especially for the reflectance-based principle. we did the simulation using the skin and fingertip models at diastolic and systolic states, which correspond to the ppg waveform’s cardiac cycle. we observed the ray-tracing behavior in the biological tissues for both principles, from the light source to the detector. the reflectance-based technique showed a higher photocurrent than the transmittance-based principle, up to a 3 mm separation distance between the light source and detector. the space more than 3 mm showed lower photocurrent detected than the transmittance-based at 7 mm. therefore, we suggest that the optimal distance between the source and detector should be less than 3 mm for the reflectancebased ppg sensor device. thus, we can enhance the ppg signal acquisition. the transmissionbased simulation also showed that the position of the source and detector significantly impacted signal acquisition. in this principle, the bone structure is one of the high-opaque materials, which reduces the light penetration to the sensor on the other side. thus, the reflectance-based has more significant advantage, especially for the wearable pulse oximetry device for a daily health monitoring system, due to its flexibility and quite convenient application on any body part. plus, the separation distance between the light source and the detector for this principle can be tailored based on the microfabrication process for integrating these two devices. acknowledgements the author would like to thank all related parties who helped the process of this research, especially to kyushu university and the ministry of education, culture, sports, science, and technology (mext), japan for their continuous support. 90 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 78-91 eissn : 2747-173x submitted : june 15, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31668 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[21] t. lister, p. a. wright, and p. h. chappell, “optical properties of human skin,” j. biomed. opt., vol. 17, no. 9, pp. 090901, 2012, doi: 10.1117/1.jbo.17.9.090901. [22] n. bosschaart, g. j. edelman, m. c. g. aalders, t. g. van leeuwen, and d. j. faber, “a literature review and novel theoretical approach on the optical properties of whole blood,” lasers med. sci., vol. 29, no. 2, pp. 453–479, 2014, doi: 10.1007/s10103-013-1446-7. 92 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 environmental radioactivity concentrations and assessment of radiological hazards in soil around bandung nuclear area juni chussetijowati1, haryo seno1,a, dani muliawan1 1national research and innovation agency, coblong, bandung, west java, indonesia aemail: ryosen7@gmail.com abstract. bandung nuclear area is an area which is nuclear reactor named triga 2000 and research laboratory located. the reactor and research laboratory are utilized for training, researching and radioisotopes production that has potential to contaminate the environment. environmental radioactivity monitoring is done periodically to find out potential radioactive release from activities inside bandung nuclear area to surroundings. however, the assessment of radiological hazards to determine the potential radiological dangers to humans and environment around bandung nuclear area is not done yet. the objective of this study is assessing the radiological hazards in bandung nuclear area by comparing the data from soil samples taken in environment radiological monitoring activity with the recommendation data based on unscear and other references to find out the radiological hazards that potentially affect to humans, where this assessment has never been carried out in this area. the assessment of radiological hazards in this study is limited to ra-226, th-232 and k-40 nuclides because contributing to radiation dose received by human. the study was conducted by collecting soil samples from several sampling points inside and outside bandung nuclear area. then, the nuclides of ra-226, th-232 and k-40 contained in soil samples are measured by using the gamma-ray spectrometry method with high resolution detector that is hpge (high purity germanium) and a computer-based multichannel analyzer (mca). the results indicated that the concentration of environmental radioactivity ranged between 11.02 to 32.66 bq/kg for ra-226; 19.44 to 43.83 bq/kg for th-232 and 56.00 to 183.39 bq/kg for k-40. this study also obtained results that the radiological hazard of the gamma dose rate ranged from 23.54 to 40.23 ngy/h, the radium equivalent was 51.77 to 89.78 bq/kg; the external hazard index was 0.14 to 0.24 and the internal from 0.18 to 0.33; the index of radioactivity level was 0.37 to 0.63. the annual effective dose equivalent for outdoor ranged from 0.03 to 0.05 msv/y and indoor was 0.12 to 0.20 msv/y. the lifetime cancer risk for outdoors ranged from 0.10x10–3 to 0.17x10–3 and indoor was 0.4x10–3 to 0.69x10–3. the values of radiological hazard were below the international requirements. there is no potential risk of natural radiation of gamma ionizing radiation exposure in soil samples around the bandung nuclear area for workers, the public, and the environment. keywords: environment, radiological, hazard, gamma, spectrometry introduction radiation has always been present in nature, and all living organisms are constantly exposed to it. cosmic rays, terrestrial radionuclides, and radionuclides in the human body are the origins of that exposure. cosmic rays (or extraterrestrial radionuclides) come from outer space and the sun's surface, but terrestrial or primordial radionuclides are found in the earth's crust, construction materials, air or atmosphere, water, and foods. the human body receives radiation from sources in the earth's crust that enter by inhalation of air, water consumption, or food consumption [1]. background radiation is another name for natural radiation. there was artificial radiation in addition to natural radiation. artificial radiation comes from radiation sources originating due to human activities. for example: radiation from radionuclides 93 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 sr-90 and cs-137. the presence of artificial radionuclides contributes to an increase in the radiation already present in the environment [1]. bandung nuclear area is an area which is nuclear reactor named triga 2000 located. the triga 2000 reactor is utilized for training, researching and radioisotopes production. also, in bandung nuclear area there is laboratories used to radioisotopes researching. if the research activities in reactor and laboratory are not held well, the artificial radioactive are potential to release and contaminate the surrounding environmental. the radioactive release also increasing the natural radiation has been present in nature. environmental radioactivity caused by artificial radioactive could affect the organism health and growth. therefore, the environmental radioactivity monitoring around bandung nuclear area is done routinely with the intention to observe the potential radioactivity release from radioactive research facilities inside bandung nuclear area to environment. environmental radioactivity monitoring around bandung nuclear area is held periodically 4 times a year every 3 month. the environmental radioactivity monitoring performed by collecting sample (soil, plant, air particulate, water and sediment) from several sampling locations. then the samples are prepared and the radioactivity contained in samples are measured by using gammaray spectrometry. assessment of radiological hazards in bandung nuclear area is not conducted yet. so, the objective of this study is assessing the radiological hazards around bandung nuclear area. the limitation of this study is comparing the values of ra-226, th-232 and k-40 measured in soil samples taken around bandung nuclear area in 2020 with recommended value provided by unscear 2000. because natural radioactivity concentrations are usually determined from the contents of ra-226, th-232, and k-40 [2], and because the dominant radiological effects are from radium and its progenies, rather than from its precursors [3], the radionuclides measured are primarily ra-226, th-232, and k-40. the measurements were made with a computer-based multichannel analyzer (mca) and genie2000 software, employing the gamma-ray spectrometry method with a high purity germanium (hpge) detector. theoretical background natural radionuclides such as u-238, th-232, and their decay products, as well as k-40, are already present in the earth's crust. the natural radionuclide, including natural radiation from u238 and its decay products, contributes significantly to human natural radiation [4]. natural radiation is the most significant contribution to the external dose, and it can be found in soil, rocks, plants, water, and air [1]. the u-238 is one of the most abundant substances in the earth's crust and can be found in trail amounts in rocks and soil. natural and human processes contribute to its reallocation in the environment, and it will gain stability by relieving energy from the nucleus. one of the decay products of u-238 is rn-222 (radon), which is a naturally occurring gas that independently migrate and distribute far away to locations and trending to accumulate within certain environments. the inhalation of radon is the main cause of lung cancer after smoking, and become the main origin of natural radioactivity exposure worldwide [5]. 94 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 figure 1. primordial radioactive decay series (a) 232th, (b) 238u and (c) 235u [6]. materials and methods the method of radiological hazards assessment in soil around bandung nuclear area is illustrated in figure 2 below. 95 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 figure 2. method of radiological hazards assessment in soil around bandung nuclear area collecting and preparing soil samples the soil has been collected for 43 (forty-three) samples around the bandung nuclear area. soil samples were taken at a radius of 100 meters, 200 meters, 500 meters, 1000 meters, and 2000 meters from the bandung nuclear reactor. this reactor type is triga mark ii nuclear reactor with an administrative area 100 meters from the reactor and surrounded by perimeter fence. for each radius of 100 m, 200 m, and 500 m, soil samples were collected at 4 (four) locations. the samples of soil were taken at 5 (five) different locations for each radius of 1000 m and 2000 m. each location is monitoring points on environmental radioactivity monitoring around bandung nuclear area which are sampled routinely once in 3 months. figure 3 depicts the location of the soil sampling. the collected samples are surface soil in widely opened area unobstructed by high buildings and trees. the surface soil samples taken based on ncrp report (national council on protection and measurement) that 80% radon gasses released to atmosphere came from surface soil. then the impurities (such as gravel, tree branches, and so on) carried during sampling collection at the site were removed from the soil samples. the soil samples were sun-dried. a soil grinder was used to grind the dried soil samples. before grinding other soil samples, the tools must be clean of the most recent impurities residual soil. the soil sample was sieved through a 200 meshes sieve to achieve uniform grain size, affine grain size, and homogeneity [7]. a digital scale was used to weigh 500 g of soil samples, which were then placed in a 500 ml marinelli beaker. the samples were sealed to prevent radon gas escape and stored for approximately 28 days before being measured and analyzed to determine the secular equilibrium of radon and its progenies [8]. 96 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 figure 3. the geographic site of sampling, radius of 100 m, 200 m, 500 m, 1000 m, and 2000 m of bandung nuclear area measurement of soil samples gamma radiation is emitted by naturally occurring radioactivity in the soil. gamma radiation was measured in soil samples using gamma-ray spectrometry, which was calibrated and equipped with a high purity germanium (hpge) detector. the detector was linked to a computer-based multichannel analyzer (mca) and genie2000 software. the program was used to analyze the gamma spectrum as well as the data collected by the detector. the gamma radiation background was measured using an empty marinelli beaker prior to the sample measurement and analysis. for 10,000 seconds, the soil samples were measured. determination of activity concentration ra-226, th-232, and k-40 the radioactivity concentration of each nuclide was calculated using the gamma radiation measurement results from the soil sample. the concentrations of ra-226 and th-232 were calculated using the energy of their progenies as they decayed. the net count of the sample was calculated by subtracting the value of the soil count from the background count. after subtracting the background, the activity of ra-226 was specified using the average gamma-ray peak intensity of pb-214 (at 351.93 kev) and bi-214 (at 609.31 kev and 1120.29 kev), and the activity of th-232 was specified using the gamma-line of ac-228 (at 338.40 kev, 911.20 kev, and 968.96 kev), pb-212 at 238.63 kev, and tl-208 (at 583.19 kev and 860.53 kev). the k-40 activity was specified directly from its gamma-line at 1.46082 mev [9]. the concentrations of each radionuclide ra-226, th-232, and k-40 in the soil sample were determined by using the formula [9]: tmp n a s  = (1) where: a is radioactivity concentration of radionuclides (bq/kg), ns is count per second netto (cps) = net count of sample – net count of background, ε is the measured peak efficiency (%), pγ is the 97 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 emission probability (the gamma-ray intensity), m is the mass of the sample (kg), and t is the sample measurement time (seconds). according to unscear 2000, the average radioactivity concentrations of radium, thorium, and potassium in the crust of the earth are approximately 33, 45, and 420 bq/kg, respectively. determination of radiological hazards the radiological hazard potential of natural radionuclides was assessed by evaluating the parameter values of the absorbed dose rate (d), radium equivalent (raeq), internal and external hazard index (hin and hex), index of radioactivity level (iγ), annual effective dose equivalent (aede) for indoor and outdoor, and excess lifetime cancer risk (elcr). absorbed dose rate (d) the absorbed dose rate denotes the rate at which radiation emitted by radionuclides in environmental materials is received outside. the gamma dose rate (absorbed) in air was measured at one meter above the surface of the ground and calculated using the contribution of natural radionuclide activity concentrations ra-226, th-232, and k-40 in the soil sample. the ra226 decay product took the place of the u-238. the gamma absorption dose rate (d) was counted up by using this formula [1]: [10] kthra aaad 0417.0604.0462.0 ++= (2) where: the absorbed gamma dose rate at one meter above the ground level (d) in ngy/h; ara, ath and ak are the specific activity concentrations of ra-226, th-232, and k-40 in soil sample (bq/kg); 0.462, 0.604 and 0.0417 are conversion factors for ra-226, th-232, and k-40 (ngyh1/bqkg–1). according to unscear, the maximum allowable absorbed gamma dose rate from soil is 59 ngy/h, with a median of 57 ngy/h and a maximum of 55 ngy/h in indonesia. radium equivalent (raeq) natural radionuclides are distributed unevenly in the environment, depending on where they are found. as a result, the radium equivalent activities (raeq) [11] have been used to determine the uniformity of radiation exposure. the radium equivalent activity was used to compare the radium, thorium, and potassium radioactivity in materials; the number of activities is expressed in the amount. the radium equivalent activities of soil samples are calculated using the assumption that 10 pci/g ra-226, 7 pci/g th-232, and 130 pci/g k-40 produce the similar dose rate of gammaray. the conversion of 1 pci/g is equal to 37 bq/kg [12] [13]. radium equivalent (raeq) was counted up by using this formula: [14] kthraeq aaara 077.043.1 ++= (3) 98 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 where: raeq is radium equivalent activities (bq/kg); ara, ath dan ak are the specific concentrations of ra-226, th-232, and k-40 (bq/kg); 1.43 and 0.077 are the conversion factors for th-232 and k-40. the radium equivalent activity was used to assess the radiation risk associated with building materials such as soil. to keep the annual dose below 1.5 mgy/y or 1.5 msv/y, the raeq limit in building materials must be less than 370 bq/kg [8] [15]. external hazard index (hex) the index of external hazard is a measure of the risk of gamma ray exposure from natural radionuclides [16]. the external hazard index (hex) was counted up by using this formula: 4810259370 kthra ex aaa h ++= (4) where: hex is external hazard index; ara, ath and ak are the specific concentrations of ra-226, th-232, and k-40 (bq/kg). to reduce the risk of external radiation received by the population, the external hazard index must be less than 1. this equates to a maximum radium equivalent value of 370 bq/kg. internal hazard index (hin) radon and thoron are the progenies of natural radionuclides decay series. radon and thoron are available in huge amount in the soil and can be released into the air and water. internal radiation exposure occurs from breathing air or consuming water or food containing radon or other nuclides. the index of internal hazard is one of the parameters used to assess the potential radiological hazards associated with natural radionuclide decay product exposure to internal radiation. radiation hazard must be negligible in the population if the values of the internal hazard index are less than one [17]. the index of internal hazard (hin) was calculated using the following formula: 4810259185 kthra in aaa h ++= (5) where: hin is internal hazard index; ara, ath and ak are the specific concentrations of ra-226, th232, and k-40 (bq/kg). radiological level index (iγ) the index of radioactivity level (iγ) is used for estimation of radiation risk level by gamma-ray from natural radionuclides [18]. 99 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 the radioactivity level index (iγ ) were counted up by using this formula: 1500100150 kthra aaa i ++= (6) where: iγ is radioactivity level index; ara, ath and ak are the specific concentrations of ra-226, th-232, and k-40 (bq/kg). the radioactivity level index value for this index must be less than 1. values of index iγ≤ 2 correspond to an absorbed gamma dose rate of 0.3 msvy–1, where as 2 < γ ≤ 6 corresponds to an absorbed gamma dose rate of 1msvy–1, andiγ> 6 correspond to dose rates higher than 1 msvy – 1, which is the highest dose rate value recommended for the population [19]. the value of radioactivity level index must be less than one. index iγ ≤ 2 values correspond to gamma dose rate (absorbed) of 0.3 msv/y, index 2 < iγ ≤ 6 correspond to gamma dose rate (absorbed) of 1 msv/y, and index iγ > 6 correspond to gamma dose rates greater than 1 msv/y, which is the population’s highest radiation dose limit according to iaea [19]. annual effective dose equivalent (aede) the absorbed dose's health effects are assessed using the annual effective dose. thus, using a conversion coefficient of 0.7 sv/gy, the annual effective dose equivalent received by humans can be calculated from the gamma absorbed dose in air. the conversion factor from the absorbed dose in air to the effective dose is thus 0.7 sv/gy. for the purposes of estimating effective dose rates in a year (1 year = 8760 hours), it is assumed that adults spend approximately 80% of their time indoors and 20% of their time outdoors. as a result, the values for the indoor and outdoor occupancy factors were 0.8 and 0.2, respectively. the population's indoor and outdoor annual effective dose rates (aede) were counted up by using the formulas listed below [1] [23]: for indoor: 𝐴𝐸𝐷𝐸(𝑚𝑆𝑣/𝑦) = 𝐷(𝑛𝐺𝑦/ℎ) 𝑥 8760 (ℎ/𝑦) 𝑥 0.8 𝑥 0.7 (𝑆𝑣/𝐺𝑦) 𝑥 10−6 (7) for outdoor: 𝐴𝐸𝐷𝐸(𝑚𝑆𝑣/𝑦) = 𝐷(𝑛𝐺𝑦/ℎ) 𝑥 8760 (ℎ/𝑦) 𝑥 0.2 𝑥 0.7 (𝑆𝑣/𝐺𝑦) 𝑥 10−6 (8) where: aede is the effective dose equivalent in a year (msv/y), d is the dose rate (absorbed) in air (ngy/h); 0.7 is the dose conversion factor, which converts the absorbed dose rate in air to human effective dose (sv/gy); 0.8 is the indoor occupancy factors; 0.2 is the outdoor occupancy factor, and 10−6 is the conversion factor of measurements. the world average effective dose rate (annual) for outdoor is 70 µsv/y (or 0.07 msv/y) [1]. excess lifetime cancer risk (elcr) the annual effective dose equivalent (aede) can be used for calculating the cancer risk. the equation is as follow. [21]: rfxdlxaedeelcr = (9) 100 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 where: dl is the duration of life (70 years in average); and rf is the factor of risk, given as 0.05 sv−1 [20] [21]. it is assumed that the average age of the population is 70 years. the elcr global value was 0.29×10–3 and 1.16×10–3 for indoor and outdoor, respectively, given by unscear [1]. results and discussion table 1 shows the results of the radioactivity concentrations of ra-226, th-232, and k-40 measured in soil samples. the activity concentration of these natural radioactive then be calculated using certain formula to obtain the radiological hazard parameters that showed in table 2. as shown in table 1, sample id/location represent the distance from triga mark ii research reactor facility. the effect of this difference in activity concentration values for each radioisotope are not affected by the distance from the presence of the reactor. natural radiation is the radioactive which already exist in nature, so they are not affected by the presence or the distance of nuclear reactors. the differences in activity concentration for each natural radionuclide in every sample depend on several factors, like composition of the soil, terrain condition, geomorphology and lithology. the activity concentration of ra-226 at location 1000-1 is slightly higher than other location possibly due to the characteristic of soil and several other factors mentioned above. therefore, the further research related to those factors is needed to do if we are willing to know the reason of difference activity concentration in samples taken from every single location. table 1. ra-226, th-232, and k-40 activity concentrations in soil samples sample id / location activity concentration (bqkg–1) 226ra 232th 40k 100-1 16.07 ± 3.71 36.24 ± 17.29 121.10 ± 13.38 100-2 13.33 ± 7.79 31.10 ± 15.01 87.53 ± 104.05 100-3 14.83 ± 1.61 19.44 ± 16.62 118.67 ±146.98 100-4 15.26 ± 3.50 31.01 ± 15.02 56.00 ± 68.08 200-1 13.51 ± 5.21 31.37 ± 14.15 166.42 ± 60.13 200-2 15.54 ± 3.11 28.14 ± 14.38 183.39 ± 50.09 200-3 12.44 ± 1.54 28.83 ± 13.58 102.77 ± 6.26 200-4 16.14 ± 2.31 33.77 ± 15.34 90.36 ± 6.87 500-1 15.56 ± 1.84 34.05 ± 16.29 89.92 ± 6.39 500-2 14.92 ± 1.31 39.74 ± 17.92 123.65 ± 32.80 500-3 13.36 ± 2.04 31.04 ± 20.76 137.98 ± 5.43 500-4 16.48 ± 2.06 32.00 ± 17.01 66.82 ± 94.49 1000-1 32.66 ± 37.02 34.01 ± 16.09 110.17 ± 16.76 1000-2 11.02 ± 2.03 24.48 ± 17.98 104.39 ± 4.60 1000-3 14.49 ± 1.97 32.35 ± 16.47 163.50 ± 66.48 1000-4 12.92 ± 1.34 32.43 ± 15.02 115.40 ± 0.90 1000-5 13.01 ± 1.01 33.81 ± 15.81 155.30 ± 5.12 2000-1 14.81 ± 1.19 33.27 ± 15.67 101.12 ± 4.92 2000-2 13.71 ± 2.33 31.50 ± 15.38 130.62 ± 14.53 2000-3 14.23 ± 2.48 37.39 ± 20.92 140.09 ± 1.50 2000-4 19.34 ± 1.98 43.83 ± 21.52 96.50 ± 24.61 2000-5 15.85 ± 2.64 32.86 ± 15.60 136.44 ± 24.82 minimum 11.02 19.44 56.00 maximum 32.66 43.83 183.39 101 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 sample id / location activity concentration (bqkg–1) 226ra 232th 40k average 15.43 32.39 118.10 stdev 4.22 4.90 32.14 unscear 2000 33 45 420 table 2 summarizes the calculation results of radiological hazard parameters in soil samples. there are seven parameters that represent the radiological hazard from natural radionuclides that can affect human body, both workers and the surrounding community. table 2. summary the result of calculation radiological hazard parameters sample id/ location d (ngyh–1) raeq (bqkg–1) hex hin iγ annual effective dose equivalent (msv/y) excess lifetime cancer risk (x 10-3) outdoor indoor outdoor indoor 100-1 34.36 77.21 0.21 0.25 0.55 0.04 0.17 0.15 0.59 100-2 28.59 64.54 0.17 0.21 0.46 0.04 0.14 0.12 0.49 100-3 23.54 51.77 0.14 0.18 0.37 0.03 0.12 0.10 0.40 100-4 28.11 63.91 0.17 0.21 0.45 0.03 0.14 0.12 0.48 200-1 32.13 71.19 0.19 0.23 0.51 0.04 0.16 0.14 0.55 200-2 31.82 69.90 0.19 0.23 0.51 0.04 0.16 0.14 0.55 200-3 27.44 61.57 0.17 0.20 0.44 0.03 0.13 0.12 0.47 200-4 31.62 71.38 0.19 0.24 0.51 0.04 0.16 0.14 0.54 500-1 31.50 71.18 0.19 0.23 0.50 0.04 0.15 0.14 0.54 500-2 36.05 81.27 0.22 0.26 0.58 0.04 0.18 0.15 0.62 500-3 30.67 68.37 0.18 0.22 0.49 0.04 0.15 0.13 0.53 500-4 29.73 67.38 0.18 0.23 0.47 0.04 0.15 0.13 0.51 1000-1 40.23 89.78 0.24 0.33 0.63 0.05 0.20 0.17 0.69 1000-2 24.23 54.06 0.15 0.18 0.39 0.03 0.12 0.10 0.42 1000-3 33.05 73.34 0.20 0.24 0.53 0.04 0.16 0.14 0.57 1000-4 30.37 68.18 0.18 0.22 0.49 0.04 0.15 0.13 0.52 1000-5 32.91 73.31 0.20 0.23 0.53 0.04 0.16 0.14 0.56 2000-1 31.15 70.17 0.19 0.23 0.50 0.04 0.15 0.13 0.53 2000-2 30.81 68.81 0.19 0.22 0.49 0.04 0.15 0.13 0.53 2000-3 35.00 78.48 0.21 0.25 0.56 0.04 0.17 0.15 0.60 2000-4 39.43 89.45 0.24 0.29 0.63 0.05 0.19 0.17 0.68 2000-5 32.86 73.35 0.20 0.24 0.53 0.04 0.16 0.14 0.56 minimum 23.54 51.77 0.14 0.18 0.37 0.03 0.12 0.10 0.40 maximum 40.23 89.78 0.24 0.33 0.63 0.05 0.20 0.17 0.69 average 31.62 70.85 0.19 0.23 0.51 0.04 0.16 0.14 0.54 stdev 4.05 9.21 0.02 0.03 0.06 0.005 0.02 0.02 0.07 unscear 2000 55 ≤ 370 < 1 < 1 < 1 0.5 msvy–1 0.5 msvy–1 table 1 showed the ra-226, th-232, and k-40 radioactivity concentrations quantified from the samples of soil. the activity concentrations of ra-226 is in the range from 11.02 to 32.66 bq/kg; th-232 is 19.44 to 43.83 bq/kg; and k-40 is 56.00 to 183.39 bq/kg. the highest concentration of ra-226 was found in locations 1000-1 and th-232 was found in location 2000-4 (table 1). while locations 200-2 had the highest level of k-40 activity. the average activity concentrations of ra226, th-232, and k-40 in soil samples were 15.43 ± 4.22 bq/kg, 32.39 ± 4.90 bq/kg, and 118.10 102 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 ± 32.14 bq/kg, respectively. these levels are lower than the unscear requirement of average activity concentration. table 2 showed the results of the calculation of the radiological hazard parameters of ra-226, th-232, and k-40 in soil sample, which include the parameters absorbed dose rate (d), radium equivalent (raeq), external hazard index (hex), internal hazard index (hin), radioactivity level index (iγ), annual effective dose equivalent (aede) and excess lifetime cancer risk (elcr). the radiological hazard of natural radioactivity concentration was assessed by comparing the calculated parameter values to approved international values. table 2 showed the gamma absorption dose rate (d) in the air was in the range of 23.54 to 40.23ngyh–1 with an average of 31.62 ± 4.05ngyh–1. the air absorption dose rate was lower than the population-weighted average of global terrestrial or primordial radiation, which was 59 ngy/h. under normal conditions, the dose rate from terrestrial gamma-rays in air is approximately 60 ngy/h, with a median value of 51 ngy/h. the average absorbed dose rate of gamma radiation in the vicinity of the bandung research reactor is less than 59 ngy/h, and thus less than the unscear 2000 average limit value [1]. the radium equivalent activity (raeq) in soil samples ranged from 51.77 to 89.78 bq/kg, with an average of 70.85 ± 9.21 bq/kg. the radium equivalent value (raeq) was less than 370 bq/kg, which was still below the allowable limits (recommended by the organization for economic cooperation and development). external hazard index (hex) values for soil samples ranged from 0.14 to 0.24 with an average value of 0.19 ± 0.02. the external hazard index (hex) value was less than one, and less than the allowable limits, indicated that there was no possible radiation risk. internal hazard index (hin) values for soil samples ranged from 0.18 to 0.33 with an average values of 0.23 ± 0.03. the value of the internal hazard index (hin) was less then one, and less than the allowable limits, indicating that there is no potential radiation risk. the value of effective dose per year (1 msv/y) indicated that the internal risk was less than the suggested value. radioactivity level index (iγ) values for soil samples ranged from 0.37 to 0.63 with an average of 0.51 ± 0.06. the value of the radioactivity level index (iγ) was less than one, it was lower than the recommended limits and does not pose a potential radiation hazard. the outdoor annual effective dose equivalent (aede) in soil samples ranged between 0.03 to 0.05 msv/y with the average values of 0.04 ± 0.005 msv/y and for the indoor ranged between 0.12 to 0.20 msv/y with the average of 0.16 ± 0.02 msv/y. the average outdoor and indoor effective dose equivalent (annual) were below the unscear average value. in average, the outdoor effective dose (annual) was less than the global value of 70 µsv/y (or 0.07 msv/y). also, in average, the effective dose for outdoor and indoor per year was 0.04 and 0.16 msv/y. thus, the total effective dose (annual) was 0.10 msv/y. it was less than the international commission on radiological protection’s (icrp) permissible value for individual members of the public [22]. the excess lifetime cancer risk (elcr) in outdoor ranged from 0.10 x 10–3 to 0.17 x 10–3 with the average values was (0.14 ± 0.02) x 10–3 and for the indoor ranged from 0.40 x 10–3 to 0.69 x 10–3 with an average was (0.54 ± 0.07) x 10–3. in average, the excess lifetimes cancer risk was less than the global value set by unscear. 103 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 92-104 eissn : 2747-173x submitted : june 26, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.31989 conclusions in this present work, the calculation for assessing the radiological hazard from natural radioactivity into human body has been studied. the three radioisotopes ra-226, th-232, and k-40 exist in the environmental soil samples around the bandung nuclear area have been quantified and analyzed. the average activity concentrations obtained from ra-226, th-232, and k-40 in soil of bandung nuclear area were less than the unscear and other references recommendation. the calculated radiological hazard values were below the value of the international requirement. this means that there is no potential risk of gamma radiation exposure from the natural radioactivity of the soil around the environmental of bandung nuclear area. therefore, the public health around the bandung nuclear area is protected from radiological hazard originating from terrestrial or primordial radionuclides in soil. acknowledgements the authors 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[23] anekwe, ul., onoja, ra., “assessment of environmental radioactivity level and its health implication in imiringi community bayelsa state nigeria”, j. appl. sci. environ. manage., vol. 24 (6) 1045-1050, 2020 114 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 analytical methods for mathematical modeling of dye-sensitized solar cells (dsscs) performance for different local natural dye photosensitizers j. b. yerima1,a, s. c ezike1, dunama william2, and alkali babangida3 1department of physics, modibbo adama university yola, nigeria 2department of mathematics, modibbo adama university yola, nigeria 3department of science education, coe azare, bauchi state, nigeria aemail: bjyerima@gmail.com abstract. in this paper, a new approach to generate the modified ideal diode factor of solar cells was developed which overcomes the problem of assuming its value a constant. five models were employed to calculate the five-model parameters of one standard solar cell and fourteen dsscs with varying photosensitizers. the results exhibit the conversion efficiencies of the solar cells studied lies in the range 2.57% ≤ η ≤ 0.03%. in particular, the standard cell has the highest efficiency 3.02% followed by dsscs with photosensitizers: bitter gourd (2.57%), mango (1%), and bougainvillea (0.83%). also, the five model parameters calculated are all positive for el tayyan model and the rest of the models show discrepancies of varying degrees. furthermore, despite the existence of these discrepancies, the results reveal good fit between the model data and experimental data i-v curves. this suggests the tendency or possibility that irregular parameters may be desirable for some applications. thus, the discrepancies found in the estimated parameters can serve as a vital assessment criterion and tool for researchers and engineers in selecting the appropriate parameter estimation method for their applications. keywords: analytical methods, mathematical modeling, dsscs, photosensitizers, irregular parameters, conversion efficiency. 1. introduction the application of renewable energy is becoming more popular in modern societies and among the various sources, photoelectric energy is one of high demand in terms of increase of installed power. in addition, many specific applications such as satellites and spacecraft have motivated researchers to study the characteristics of photovoltaic cells, how to improve their power generation in the last three decades, and describe mechanisms that control the conversion of solar radiation into electric power [1-6]. also, tremendous efforts have been made to obtain equivalent electrical/mathematical models to explain the behavior of solar cells under various conditions such as different radiation levels, photosensitizers, and cell temperatures. an electrical model consists in a simple electric circuit whose behavior matches the real behavior of solar cell [29]. the application of circuit models together with relevant electric parameters is very crucial to optimize the power derived from the cell working under real conditions. furthermore, the application of equivalent circuit models makes the simulation of more complicated power systems that include solar cell panels possible. in practice, in space applications these power complicated systems include batteries and programmed power consumption, with important temperature gradients and different radiation levels affecting the 115 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 output voltage of the solar cell/panel and must be maximized to ensure the survival of the spacecraft. the photovoltaic effect leads to the conversion of sunlight radiation falling on solar cells into usable electric energy. in general, the simplest way to characterize a solar cell is by considering a current source connected in parallel to an ideal diode. the current-voltage equation that explains the theory behind the behavior of the solar cell is called shockley’s ideal diode equation given by 𝐼 = 𝐼𝑝ℎ − 𝐼𝑜 (𝑒 𝑉 𝑛𝑉𝑇 − 1) (1) where the first term iph, is the photocurrent delivered by the constant current source, the second term is the ideal recombination current from the diffusion and recombination of electrons and holes in p-n junction sides of the cell, io is the reverse saturation current corresponding to it, vt is the thermal voltage, and n is the diode ideality factor. the thermal voltage vt is defined by 𝑉𝑇 = 𝑘𝑇 𝑞 (2) where t is the absolute temperature, q is the charge of the electron, and k is the boltzmann’s constant. figure 1. electrical equivalent circuit of the single-diode solar cell in order to modify equation (1) to better fit the solar cell behavior, shunt resistor rsh and series resistor rs are usually added to the circuit (fig.1). the shunt resistor is connected in parallel with the source and diode and it represents the current leakage through the high conductivity shunts across the p-n junction while the series resistor is added in series and it represents the losses in cell solder bonds, interconnection, junction box, and so on [4, 7]. also, a dimensionless constant, n, called ideality/quality factor or emission coefficient is added to the term of the recombination current in the pand n-sides and it takes into account the deviation of the diodes from the shockley diffusion theory. the value of this factor depends on the ratio between current i and voltage v of the cell (10). the one-diode and two-resistors circuit model is then defined by equation (3) 116 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 𝐼 = 𝐼𝑝ℎ − 𝐼𝑜 [𝑒𝑥𝑝( 𝑉+𝐼𝑅𝑠 𝑛𝑉𝑇 ) − 1] − 𝑉+𝐼𝑅𝑠 𝑅𝑠ℎ (3) the modified form a of the ideal factor n of the diode is defined by equation (4) 𝑎 = 𝑛𝑁𝑠𝑉𝑇 = 𝑛𝑁𝑠 𝑘𝑇 𝑞 (4) where ns is the number of solar cells connected in series i.e. ns=1 for single-diode solar cell. in another vein, it has been reported by some authors [8, 9] that the easiest and more commonly used 1-diode/2-resistors model exactly reveals the behavior of the solar cell around the maximum power point, that is, at high voltage levels. this model simplifies the study of the solar cell behavior as a function of the various circuit variables [10-13], and has been employed to examine the effect of the irradiance and the temperature on the cell behavior. once the circuit model has been selected to investigate a specific solar cell, it must be modified, that is, the value of the circuit parameters must be calculated as accurately as possible. these calculations can be based on calibration results of the cell such that once the i-v curve are obtained under definite irradiance and temperature conditions in a laboratory, the parameters of the model can be adjusted to give the best possible fit to this curve [14, 18-23, 46]. nevertheless, sometimes the only data available to adjust the chosen circuit model comes from the manufacturer and it is restricted to only certain points on the i-v graph (short-circuit, open circuit, and maximum power points) [10, 16, 23-28]. in a nut shell, with respect to the existing methods to adjust the parameters of the chosen circuit model, some of them are numerical [11, 12, 15, 29,30, 46] while some others are analytical [2, 31-33, 45]. analytical methods are preferred because they are simple and fast. obviously, these methods usually rely on experimental behavior of the i-v curve, that is, they demand wide range of testing results [34]. alternatively, some researchers have established numerical methods to adjust the electric circuit parameters to the listed characteristic point of the curve [16, 17, 22, 28]. this technique is quite motivating, as it requires only a few data to allow final users to explain the performance of photoelectric devices. in this paper, analytical methods for photovoltaic equivalent electric circuit parameters extraction from experimental observations are reported. these approaches are based only on the points on the i-v curve (short-circuit, open circuit, and maximum power points) for modeling dsscs performance for different local natural dye photosensitizers. the approach to the experimental parameter extraction problem for dssc systems studied does not seem to have been studied as yet. 2. modelings 2.1 el tayyan model the el tayyan model [35] for generating the i-v characteristics of a solar cell or pv module is given by 117 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 𝐼 = 𝐼𝑠𝑐 − 𝐶1⁡𝑒 − 𝑉𝑜𝑐 𝐶2 (𝑒 𝑉 𝐶2 − 1) (5) where c1 and c2 are coefficients of the model equation with units of current and voltage respectively. using the short-circuit (sc), open-circuit (oc) and maximum power point (mpp) conditions and assuming 𝑉𝑜𝑐 𝐶2 ≫ 1⁡𝑎𝑛𝑑⁡ 𝑉𝑚𝑝 𝐶2 ≫ 1 yields 𝐶1 = 𝐼𝑠𝑐−𝐼𝑚𝑝 𝑒 𝑉𝑚𝑝−𝑉𝑜𝑐 𝐶2 (6) 𝐶2 = 𝑉𝑚𝑝−𝑉𝑜𝑐 𝑊−1((1− 𝑉𝑜𝑐 𝑉𝑚𝑝 )( 𝐼𝑚𝑝 𝐼𝑠𝑐 )) (7) where w-1 is the lower branch of the lambert w function. substituting the values of the currents and voltages at the characteristic points sc(isc, 0), oc(0, voc) and mpp(imp, vmp) on the i-c curve in equations (6) and (7) the values of c1 and c2 can be determined. also, substituting the values of c1 and c2 in equation (5) yields the desired el tayyan empirical model for a single-diode solar model. subsequently, for any given value of voltage v, the output current i in equation (5) can be calculated. it is worth noting that since the el tayyan empirical model has only two coefficients, c1 and c2, it means it is a two-parameter model. this fact can be established by comparing equations (1) and (5) which yields the two parameters io and a of the five model parameters of a single-diode solar cell given by 𝐼𝑜 = 𝐶1𝑒 − 𝑉𝑜𝑐 𝐶2 (8) 𝐶2 = 𝑛𝑉𝑇 = 𝑎 (9) the validity of equations (8) and (9) can be justified. thus, equation (8) is valid since io has same units of current with c1 as the exponent is dimensionless whereas equation (9) is valid since it is equal to equation (4). the modified ideality factor a of the diode is not usually available on the manufacturer’s datasheet and is not easily deduced on the i-v curve which makes some authors [39, 40] to guess its value and others [41-44, 45] reduce their models to less than five parameters. the advantage of the el tayyan model over other existing models is that it doesn’t require the knowledge of the internal pv system parameters and involve less computational efforts or extra measurements. it is against this background, el tayyan model combined with two models [39, 40] that assumed constant a produced two additional models, el tayyan-cubas model and el tayyan-senturk model. therefore, in this work, five models are used to calculate the five model parameters (a, iph, io, rs, rsh) to generate model i-v curves for fifteen dsscs for comparison purposes. 118 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 2.2 cubas model the cubas model [39] assumed the ideal diode factor n=1.1 for the silicon cells studied and the modified diode factor a is given by equation (4). the following auxiliary parameters a, b, c, and d in equations (10-13) are used to calculate rs in equation (14) 𝐴 = 𝑎 𝐼𝑚𝑝 (10) 𝐵 = 𝑉𝑚𝑝(𝐼𝑠𝑐−2𝐼𝑚𝑝) (𝑉𝑚𝑝𝐼𝑠𝑐+𝑉𝑜𝑐(𝐼𝑚𝑝−𝐼𝑠𝑐)) (11) 𝐶 = 𝑉𝑜𝑐−2𝑉𝑚𝑝 𝑎 + 𝑉𝑚𝑝𝐼𝑠𝑐−𝑉𝑜𝑐𝐼𝑚𝑝 (𝑉𝑚𝑝𝐼𝑠𝑐+𝑉𝑜𝑐(𝐼𝑚𝑝−𝐼𝑠𝑐)) (12) 𝐷 = 𝑉𝑚𝑝−𝑉𝑜𝑐 𝑎 (13) 𝑅𝑠 = 𝐴[𝑊−1(𝐵𝑒 𝐶) − (𝐷 + 𝐶)] (14) where w-1 is the lower branch of the lambert w function. the remaining parameters rsh, io. and iph are calculated by equations (15), (16), and (17) respectively. 𝑅𝑠ℎ = (𝑉𝑚𝑝−𝐼𝑚𝑝𝑅𝑠)(𝑉𝑚𝑝−𝑅𝑠(𝐼𝑠𝑐−𝐼𝑚𝑝)−𝑎) (𝑉𝑚𝑝−𝐼𝑚𝑝𝑅𝑠)(𝐼𝑠𝑐−𝐼𝑚𝑝)−𝑎𝐼𝑚𝑝 (15) 𝐼𝑜 = [𝐼𝑠𝑐 (1 + 𝑅𝑠 𝑅𝑠ℎ ) − 𝑉𝑜𝑐 𝑅𝑠ℎ ]𝑒 − 𝑉𝑜𝑐 𝑎 (16) 𝐼𝑝ℎ = 𝐼𝑠𝑐 (1 + 𝑅𝑠 𝑅𝑠ℎ ) (17) 2.3 el tayyan-cubas model in this model, the modified ideal diode factor a in cubas model is replaced by the second characteristic coefficient el tayyan’s model i.e., c2=a and equations (10-17) remain the same. 2.4 senturk model this model is applicable to standard test conditions (stc) [37] and other conditions as well. this model assumes the diode factor n=1.2 and the modified ideal factor a is calculated using equation (4). then, the experimental resistances rsho and rso are approximated by equations (18) and (19) respectively 𝑅𝑠ℎ𝑜 = 𝑉𝑚𝑝 𝐼𝑠𝑐−𝐼𝑚𝑝 (18) 𝑅𝑠𝑜 = 𝑉𝑜𝑐−𝑉𝑚𝑝 2𝐼𝑚𝑝 (19) thereafter, iph and io are calculated by equations (20) and (21) respectively 𝐼𝑝ℎ = (𝑅𝑠𝑜+𝑅𝑠ℎ𝑜)𝐼𝑠𝑐 𝑅𝑠ℎ𝑜 (20) 𝐼𝑜 = 𝐼𝑝ℎ− 𝑉𝑜𝑐 𝑅𝑠ℎ𝑜 𝑒 𝑉𝑜𝑐 𝑎 −1 (21) and finally, rs via phang’s model [32] and rsh by equations (22) and (23) respectively. 119 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 𝑅𝑠 = 𝑅𝑠𝑜 − 𝑎 𝐼𝑜 𝑒 −𝑉𝑜𝑐 𝑎 (22) 𝑅𝑠ℎ = 𝑉𝑚𝑝+𝐼𝑚𝑝𝑅𝑠 𝐼𝑝ℎ−𝐼𝑚𝑝−𝐼𝑜(𝑒 𝑉𝑚𝑝+𝐼𝑚𝑝𝑅𝑠 𝑎 −1) (23) 2.5 el tayyan-senturk model similarly, in this model, a in senturk model is set equal to c2 i.e., a=c2 and equations (18-23) remain the same. in practice, it is sometimes possible to differentiate the explicit model that produces the worst approximation to the data, but it is not possible to choose the best option with a proper criterion beyond a visual impression. for this reason, the results are usually analyzed using the normalized root mean-squared error (rmse) denoted by in equation (24) 𝜀 = 1 𝐼𝑠𝑐 √ 1 𝑁 ∑ (𝐼𝑐𝑎𝑙,𝑗 − 𝐼𝑗) 2𝑁 𝑗=1 (24) besides, the difference between the output current calculated with models and the one from the experimental data, related to the short-circuit current is given by equation (25) 𝜉 = 𝐼−𝐼𝑒𝑥𝑝 𝐼𝑠𝑐 (25) 3. materials and methods 3.1 materials the materials used in the work were chemicals, reagents and equipment viz: ethanol, titanium dioxide nano powder, hydrochloric acid, acetic acid, mortar and pestle, stainless steel mesh, filter paper, doctor tape c, scanning electron microscope, solar energy simulator, spectrophotometer, magnetic stirrer, glass bottle, aluminium foil, glue, adhesive tape, acetone, anhydrous alcohol, strips of glass insulation spacers, iodide electrolyte solution, n719 dye, plant dyes, centrifuge machine, sonicator, fourier transform infrared spectrometer, fluorine doped tin oxide (fto), deionized water. 3.2 methods 3.2.1 extraction of plants dyes fourteen plants parts were selected and allowed to dry on shade for two weeks. the dried fruits and flowers were grinded into fine powder using a blinder (walmat blstvb-rvo-000). 0.5 g, 1 g, and 2 g each of the selected samples were weighed on weighing balance and 5 % of the extracts were obtained respectively. the weighed powdered samples were collected in sterile 50 ml falcon tubes. 20 ml of ethanol was then added and were vortexed. the solutions were sonicated using a sonicator (branson sfx250) for 1 h at 40 c. the samples were then centrifuged at 1500 rpm in 40 c for 10 min. the solid residues were filtered out while the supernatants of the clear dry solutions were collected, and stored at 40 c before use. the containers were covered with aluminium foil to prevent damage from light exposure [47,48]. 120 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 3.2.2 assemblage of solar cells fluorine doped tin oxide (fto) of resistance 14 ω/cm2 (tco 2215 salonix) substrate was cleaned in surfactant, deionized water, acetone and ethanol. paste of tio2 was prepared with 0.25 g of tio2, 0.5 ml of acetic acid and mixture of deionized water and ethanol at ratio of 1:1 (10 ml), and stirred for 20 min, to prevent the agglomeration of the particles. triton–x 0.5 ml (salonix) was added, the resultant mixture was grounded to facilitate coating of the colloid on the substrate in order to obtain homogenous paste. doctor blade technique was adapted to coat the tio2 paste on fto glass substrate with active area of 0.16 cm2. tio2 coated films were sintered at 450 0c for 30 min. the films were cooled at room temperature. to attain sensitization of dye, films were dipped in dye like ethanolic solution of the plant dyes for 24 h. the sensitized electrodes were rinsed with ethanol to remove the unanchored dyes. counter electrode was obtained by placing a thin layer of platisol which was squeezed printed using a polyester mesh sintered at 450 0c for 30 min. a drop of iodolyte tg – 50 was casted on the surface of sensitized photo anodes, to penetrate into the porous structure via capillary action. the pt-coated fto electrode was then clipped onto the top of dye absorbed tio2 working electrode to form the complete solar cell. the photo electrochemical cell (pec) was then mounted in a sample holder inside a metal box with an area of 1 cm2 opening to allow light from the source. the photoelectrode and the counter electrode were overlappingly placed in a holder so that the titanium dioxide covered area of the photoelectrode was the only part of the photoelectrode that was in contact with the counter electrode. the non-titanium dioxide covered area of the photoelectrode and the nonoverlapping edge of the counter electrode were connected to the measuring equipment by means of cords and crocodile clips. all experiments were carried out at ambient temperature. the image of one of the assembled cells is shown in fig. 2. figure 2. assembled dssc 3.2.3 characterization of extracted dyes and solar cells the photovoltaic parameters of the fabricated dsscs were measured using a computer controlled digital source meter (keithley, 2400) and a solar simulator (am 1.5 g, 100 mw cm− 2 oriel) as light source. the light intensity was adjusted with a reference silicon cell (pv measurement co). the sample was masked with black opaque tape along the board of the active area. the photovoltaic parameters, open circuit voltage (voc), short circuit current density (isc), fill factor (ff) and overall efficiency (η) were obtained from iv curve. 121 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 4. results and discussion table 1. characteristic parameters (isc, imp, vmp, voc, pmax, ff, η) of the solar cells studied source of natural dye photovoltaic parameters english name scientific name isc (ma) imp (ma) vmp (v) voc (v) pmax (mw) ff η % control tio2/n719 9.355 7.574 0.4 0.590 3.028 0.54 3.02 witch seed flower striga hermonthica 1.970 1.379 0.4 0.639 0.551 0.43 0.55 bitter gourd momordica charantia 9.244 6.450 0.4 0.536 2.580 0.51 2.57 bougainvillea bougainvillea 3.450 2.783 0.3 0.484 0.834 0.50 0.83 flamboyant delonix regia 1.717 1.442 0.4 0.610 0.576 0.55 0.57 wild marigold calendula arvensis 1.600 0.957 0.3 0.504 0.287 0.35 0.28 red cockscomb celosia cristata 1.580 1.290 0.3 0.490 0.387 0.49 0.38 lantana lantana camera 1.530 1.262 0.4 0.600 0.504 0.54 0.50 hibiscus hibiscus rosa sinensis 1.480 1.090 0.3 0.450 0.327 0.49 0.32 sun flower helianthus 1.590 1.081 0.4 0.530 0.432 0.51 0.43 rose flower rosa 1.690 1.283 0.4 0.563 0.512 0.53 0.51 orange peel citrus aurantium 1.400 1.121 0.2 0.370 0.224 0.43 0.22 tomato lycopersicon esculentum 0.230 0.135 0.2 0.290 0.027 0.40 0.03 mango peel mongifera indica 2.51 2.130 0.4 0.618 0.852 0.76 1.00 guava peel psidium guajava 0.900 0.669 0.3 0.452 0.201 0.49 0.20 table 1 depicts the characteristic parameters of the solar cells studied. the results show that the dssc with witch seed flower dye has the highest conversion efficiency 2.57 %, second mango peel 1 %, and third bougainvillea 0.83 % after the standard cell 3.02 %. in this paper, i-v curve matching is done only for measured and calculated model data from these four solar cells for clarity. using the values of the characteristic points (isc, imp, voc, vmp) in table 1, the el tayyan coefficients or model parameters were computed (table 2). table 2. el tayyan model parameters of the solar cells studied source of natural dye el tayyan model parameters english name scientific name c1 c2 a=c2 n io (a) control tio2/n719 0.009838 0.195796 0.195796 7.5626 4.833×10-4 witch seed flower striga hermonthica 0.009700 0.062867 0.062867 2.4282 1.872×10-4 bitter gourd momordica charantia 0.009245 0.060393 0.060393 2.3327 1.293×10-6 bougainvillea bougainvillea 0.003927 0.229684 0.229684 8.8715 4.775×10-4 flamboyant delonix regia 0.001862 0.238962 0.238962 9.2299 1.450×10-4 wild marigold calendula arvensis 0.001777 0.218650 0.218650 8.4453 1.773×10-4 red cockscomb celosia cristata 0.001830 0.246337 0.246337 9.5148 2.504×10-4 lantana lantana camera 0.001632 0.216544 0.216544 8.3640 1.022×10-4 hibiscus hibiscus rosa sinensis 0.001558 0.150090 0.150090 5.7972 7.769×10-5 sun flower helianthus 0.001590 0.054753 0.054753 2.1148 9.943×10-8 rose flower rosa 0.001695 0.095372 0.095372 3.6837 4.628×10-6 orange peel citrus aurantium 0.001946 0.291046 0.291046 11.241 6 5.457×10-4 tomato lycopersicon esculentum 0.000230 0.043932 0.043932 1.6969 3.130×10-7 mango peel mongifera indica 0.002760 0.257501 0.257501 9.9459 2.504×10-4 guava peel psidium guajava 0.000951 0.154409 0.154409 5.9640 5.091×10-5 122 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 using the values of the characteristic points in equations (6) and (7), the numerical values of the el tayyan coefficients or model parameters (c1, c2) were computed (table 2). the emergence of the two coefficients suggests that the el tayyan model is a two-parameter model, the parameters being the modified ideal diode factor a and the diode saturation current io which are related to c1 and c2 via equations (8) and (9). equation (8) shows io is function of both c1 and c2 whereas equation (9) reveals a is equal to c2. the values of io and a were computed using equations (8) and (9) respectively. the results show all the parameters are regular i.e. they have positive values. furthermore, a depends on the type of dye used to fabricate the solar cell. thus, in our model, the el tayyan modified ideal factor c2=a, is used to generate a set of four model parameters (io, iph, rs, rsh) for systems where previous researchers assumed the diode ideal factor constant, n=1.1 [39] and n=1.2 [40] for comparison purpose (table 3). table 3. el tayyan-cubas model parameters for the solar cells studied natural dye cubas/el tayyan model parameters, n or a not constant cubas model parameters n=1.1 or a=0.028479 english name a rs (𝞨) rsh (𝞨) io (a) iph (ma) rs (𝞨) rsh (𝞨) io (a) iph (ma) control 0.1958 -0.8 -109.9 7.27×10-4 9.42 15.8 339.5 8.10×10-12 9.79 witch seed flower 0.0629 42.0 -245.8 3.67×10-4 1.63 124.3 711.0 2.55×10-13 2.31 bitter gourd 0.0604 -0.4 184.8 8.84×10-7 9.22 8.3 152.7 4.18×10-11 9.75 bougainvillea 0.2297 30.0 -22.0 2.52×10-3 -1.25 45.8 1160.0 1.32×10-10 3.59 flamboyant 0.2390 19.1 -239.7 3.21×10-4 1.58 99.4 2993.6 7.83×10-13 1.77 wild marigold 0.2187 94.8 57.1 7.75×10-4 -1.06 146.8 375.2 1.82×10-11 2.23 red cockscomb 0.2463 87.7 -20.0 2.62×10-3 -5.34 104.5 3568.7 5.02×10-11 1.63 lantana 0.2165 7.3 -420.7 1.83×10-4 1.50 104.3 2562.1 9.62×10-13 1.59 hibiscus 0.1501 -5.6 -1052.3 9.55×10-5 1.49 77.7 981.3 1.56×10-10 1.60 sun flower 0.0548 -3.5 957.6 6.44×10-8 1.58 42.0 829.4 8.53×10-12 1.67 rose flower 0.0954 0.7 3032.4 4.11×10-6 1.69 68.0 1185.0 3.41×10-12 1.79 orange peel 0.2910 131.6 21.5 -2.03×10-3 9.97 123.0 -584.4 3.96×10-9 1.11 tomato 0.0839 -92.1 2457.0 1.40×10-7 2.21 107.5 2171.9 4.08×10-9 0.24 mango peel 0.2575 20.7 -115.0 6.71×10-4 2.06 71.6 2552.7 8.80×10-13 2.58 guava peel 0.1544 -3.0 -1317.4 6.67×10-5 9.02 130.7 1707.1 9.01×10-11 0.97 table 3 contains two model parameters generated from cubas model for n fixed or constant (n=1.1) for all solar cells and cubas-el tayyan model for n varying with dyes or photosensitizers used in fabricating the solar cells. for the cubas-el tayyan model, all the model parameters except a manifest parameters’ irregularities i.e. the parameters have both negative and positive values. the number of negatives values are 0, 6, 9, 1, 3 for the parameters a, rs, rsh, io, iph respectively. also, the two models produce different values for all the model parameters except iph have same values and io values for cubas model have smaller values compared to those of cubas-el tayyan values. furthermore, the values of iph in table 3 are not equal to the values of isc in table 1 but they are of the same order of magnitude. table 4. el tayyan-senturk model parameters for the solar cells studied. natural dye senturk/el tayyan model parameters, n or a not constant senturk model parameters n=1.2, a=0.031068 123 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 english name a rs (𝞨) rsh (𝞨) io (a) iph (ma) rs (𝞨) rsh (𝞨) io (a) iph (ma) control 0.1958 -13.1 319.8 3.74×10-4 9.877 8.3 211.8 4.10×10-11 9.877 witch seed flower 0.0629 82.1 21.5 5.38×10-7 2.222 84.4 20.2 1.62×10-11 27.186 bitter gourd 0.0604 0.8 145.1 8.63×10-7 9.930 5.5 134.0 1.98×10-10 9.930 bougainvillea 0.2297 -43.7 361.0 3.64×10-4 3.704 21.2 411.1 4.51×10-10 3.704 flamboyant 0.2390 -86.5 2550.0 1.17×10-4 1.803 50.4 1372.6 4.11×10-12 1.803 wild marigold 0.2187 -115.8 216.6 9.82×10-5 1.966 71.5 369.4 7.98×10-11 1.966 red cockscomb 0.2463 -100.8 807.3 1.93×10-4 1.692 48.2 946.5 1.72×10-10 1.692 lantana 0.2165 -88.6 2316.8 8.07×10-5 1.611 53.5 1407.5 4.96×10-12 1.611 hibiscus 0.1501 -70.0 664.0 5.39×10-5 1.612 38.6 697.2 5.26×10-10 1.612 sun flower 0.0548 7.3 785.9 6.54×10-8 1.712 30.2 738.9 4.05×10-11 1.712 rose flower 0.0954 -14.1 1139.4 3.36×10-6 1.799 38.2 925.8 1.65×10-11 1.799 orange peel 0.2910 -127.1 169.6 4.02×10-4 1.548 45.7 621.1 6.94×10-9 1.548 tomato 0.0839 -7.4 1724.8 1.74×10-7 0.266 91.9 1757.7 1.14×10-8 0.266 mango peel 0.2575 -63.3 1966.7 2.04×10-4 2.632 36.0 992.1 4.70×10-12 2.632 guava peel 0.1544 -118.1 1126.6 3.57×10-5 0.979 64.3 1179.6 3.03×10-10 0.979 table 4 depicts the values of model parameters generated from two models, senturk model for n fixed (n=1.2) and senturk-el tayyan model for n varying for all solar cells. for the senturk-el tayyan model, all the model parameters are regular except rs has 13 values negative i.e. only rs manifests parameter irregularity. also, all the el tayyan model parameters differ from that of cubas model parameters except iph values. however, the iph values differ from isc values (table 1) and the io values for both models (table 4) differ from those of el tayyan in table 2. thus, the overall results show that the number of parameter irregularity vary with model. the acceptance of the significance of the parameter irregularity lies in the validity of the fitness between the model data and measured data i-v curves. however, in this paper, the fitting of i-v curves is done for only the first four solar cells with high efficiencies for clarity. 124 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 (a) standard (b) bitter gourd 125 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 (c) bougainvillea (d) mango peel figure 3. curves for the explicit models analyzed, fitted to the (a) standard (control) (b) bitter gourd (c) bougainvillea and (d) mango solar cells data using the analytical methods proposed. 126 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 figures 3(a-d) depict the i-v curves of solar cells (a) control (b) bitter gourd (c) bougainvillea and (d) mango for measured data and five models: el tayyan, el tayyan-cubas, el tayyan-senturk, cubas, and senturk. the figures show the i-v curves are at constant current source at low voltages with a current approximately equal to the short-circuit current, isc. with increasing voltage at a certain point, the current begins to drop off exponentially to zero at open-circuit voltage, voc. the values of voc varies with dssc as well as model which is distinctly shown in (a) el tayyan model and in (a/d) el tayyan-cubas model. over the entire voltage range, there is one point where the cell operates at the highest efficiency; this is the maximum power point, mpp (vmp, imp). the system design is to operate the cell at that point. however, the system design is complicated by the fact that the maximum power point varies with irradiance and temperature. it is worth noting the mpp changes with model. (e) control (f) bitter gourd 127 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 (g) bougainvillea (h) mango peel figure 4. curves for the explicit models analyzed taking error into account, fitted to the (e) standard (control) (f) bitter gourd (g) bougainvillea and (h) mango solar cells data using the analytical methods proposed. figs. 4(e-h) depict best i-v curve fits after eliminating the error between output current model and measured current. the values 𝜀 of the normalized root mean squared error (nrmse) of the output currents were generated using equation (24) which lie in the range 0.015<< 𝜀<<0.536 for all dsscs and models. based on the fact that the best model has the smallest value of 𝜀, our results 128 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 show that dssc/best model as follows: dssc control/el tayyan model 𝜀=0.078, dssc bitter gourd/el tayyan model 𝜀=0.109, dssc bougainvillea/senturk model 𝜀=0.129, and dssc mango/el tayyan-senturk model 𝜀=0.015. (i) control (j) bitter gourd 129 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 (k) bougainvillea (l) mango peel figure 5. fig. 5 curves for output current errors in relation to short circuit current for the explicit models (i) control (j) bitter gourd (k) bougainvillea and (l) mango solar cells data. the differences between the output currents calculated with models using equation (25) mand output currents measured in relation to the short-circuit current and figs. 5(i-k) depict current differences for the models and dsscs studied. 130 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 2, page 114-132 eissn : 2747-173x submitted : august 14, 2022 accepted : october 24, 2022 online : november 11, 2022 doi: 10.19184/cerimre.v5i2.33499 conclusion in this paper, the el tayyan empirical formula in conjunction with other exponential pv model equations were used to obtain the value of the modified ideal diode factor instead of assuming its value a constant as proposed by some authors [39, 40]. five models, el tayyan, el tayyan-cubas, el tayyan-senturk, cubas, and senturk were employed to extract the five model parameters for fifteen dsscs. the results show that in terms of conversion efficiency, next to the standard solar cell, the most efficient dsscs are the ones with photosensitizers namely bitter gourd, bougainvillea, and mango. also, the results reveal all the model parameters are regular for el tayyan model while they are irregular with varying degrees for the rest of the models. in addition, despite the parameter irregularities, there is good match between the model data and measured data i-v curves meaning presence of irregular parameters may not be undesirable for some applications. thus, the irregularities associated with the extracted parameters revealed by these methods can serve as a useful assessment criterion and tool for researchers and engineers in deciding the proper extraction method for their application. references [1] pfann, w.; van roosbroeck, w. detailed balance limit of efficiency of p-n junction solar cells. j. appl. phys. 25 (1954) 1422 [2] prince, m. b. silicon solar energy converters. j. appl. phys. 26 (1955) 534-540. 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[36] saleem, h.; karmalkar, s. an analytical method to extract the physical parameters of a solar cell from four points on an illuminated j-v curve. ieee electron device lett. 2009, 30 349-352. [37] saloux, e.; teyssedou, a.; sorin, m. explicit model of photovoltaic panels to determine voltages and current at the maximum power point. sol. energy 2011, 85, 713-722. [38] khan,f.; back, s. h.; kim, j. h. extraction of diode parameters of silicon solar cells under high illumination conditions. energy convers. manag. 2013, 76, 421-429. [39] cubas, j.; pindado, s.; victoria, m. on the analytical approach for modeling photovoltaic systems behavior.j. power sources 2014, 247, 467-474. [40] senturk, a.; eke, r. a new method to simulate photovoltaic performance of crystalline silicon photovoltaic modules based on datasheet values. renew. energy 2017, 103, 5869. [41] sera, d.; teodorescu, r.; rodriguez, p. in: ieee int. symposium on industrial electronics (isie), 2007, pp. 2392-2395. [42] khezzar, r.; zereg, m.; khezzar, a. modeling improvement of the four-parameter model for photovoltaic modules. solar energy 110, 2014, 452-462. [43] aldawane, b. modeling, simulation and parameters estimation for photovoltaic module. in proceedings of the 2014 1st internatinal conference on green energy icge 2014, sfax, tunisia, 25-27 march 2014; pp. 101-106. [44] cannizzaro, s.; di piazza, m. c.; luna, m.; vitale, g. pvid: an interative matlab application for parameter identification of complete and simplified single-diode pv modules. in proceedings of the 2014 ieee 15th workshop on control and modeling for power electronics (compel), santander, spain, 22-25 june 2014. [45] orioli, a.; di gangi, a. a procedure to calculate the five-parameter model of crystalline silicon photovoltaic modules on the basis of the tabular performance data. appl. energy 102 (2013) 1160. [46] gow, a.; manning, c. d. (1999) development of a photovoltaic array model for use in power-electronics simulation studies. ieee proceedings-electric power applications, 146, 193-200. [47] a. babangida, j.b. yerima, a.d. ahmed, s.c. ezike, strategy to select and grade efficient dyes for enhanced photo-absorption, afr. sci. rep. 1 (2022) 16–22. [48] j.b. yerima, a. babangida, s.c. ezike, w. dunama, a.d. ahmed, matrix method of determining optical energy bandgap of natural dye extracts, j. appl. sci. environ. manage., 26 (5) 943–948. http://refhub.elsevier.com/s0030-4026(22)01330-4/sbref15 http://refhub.elsevier.com/s0030-4026(22)01330-4/sbref15 http://refhub.elsevier.com/s0030-4026(22)01330-4/sbref15 http://refhub.elsevier.com/s0030-4026(22)01330-4/sbref15 http://refhub.elsevier.com/s0030-4026(22)01330-4/sbref15 1 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 high-efficiency dye-sensitized solar cells: a comprehensive review ankit stephen thomas department of chemical engineering, national institute of technology karnataka, surathkal, india ankitsthomas@gmail.com abstract. keeping in mind our community's dependency on non-renewable sources of energy, it is a gravitating issue that seeks our attention and requires us to switch to renewable sources of energy at the earliest. a dye-sensitized solar cell (dssc) is a third-generation photovoltaic technology that has immense capability to become highly commercial in a few years. along the same lines, it is necessary to highlight that current dsscs have shallow lifetime values, stability and performance. the efficiency of current dsscs and the need to tackle their choice of materials and long-term stability is a concern. some of the highest recorded efficiency values are around 12%, and this calls for severe replacement of conventional dssc materials, modifications in the device structure and molecules, and improvement in testing and scaling-up measures. this review article underlines an introduction to dsscs, working principle, components, high-efficiency dsscs, strategies to improve device performance, dsscs research in india, the advantages and disadvantages of the device, and recent research on fruit and flower-based dsscs. keywords: dye-sensitized solar cells, solar cell materials, third generation photovoltaics, high-efficiency dye-sensitized solar cells, solar cells. introduction the commercial photovoltaic technologies present in today's market are fabricated using inorganic materials that are energy and cost-intensive. moreover, these are manufactured from materials such as cdte, which are not that abundant in nature. organic photovoltaics do not possess such an issue, but their low efficiencies are still a concern. organic photovoltaics use a donor-acceptor system which is responsible for exciton generation. a dye-sensitized solar cell (dssc) requires a dye/photoanode interface responsible for charge generation and an electrolyte responsible for dye regeneration. the spectral absorption properties of the dye can be modified by altering the dye properties. in contrast, the charge transport and dynamics can be optimized by modulating the electrolyte and photoanode. dssc is an economic and a soon-to-be commercial device with a promising future ahead. this comprehensive review article highlights the various high-efficiency dyesensitized solar cells that have been fabricated. it also discusses the simple concepts of a dssc, its working principle, the pros and cons of this remarkable device, and strategies to improve its performance. moreover, since this topic is of budding interest, especially in india, the review throws light on the ongoing research about each component of a dssc and specific important examples of fruit and flower-based dyes as a photosensitizer. a dssc is a low-cost solar technology belonging to the group of third-generation photovoltaics. it consists of a photosensitizer sandwiched between a redox electrolyte and a photoanode and the respective electrodes. the current version available of dsscs is also known as a grätzel cell. along with being low-cost, the device can also be fabricated on flexible substrates and non-glass 2 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 based systems. unlike other photovoltaic technologies, the usage of expensive materials like pt, ag and au has been removed with the introduction of dsscs. although this invention results in poor stability and performance compared to other energy sources, the price to performance ratio is theoretically comparable, if not better, than other sources. the dssc, when compared to si-solar cell, is different in two unique ways. firstly, in a si-solar cell, the silicon solar cell behaves as an electron-hole pair generator and the charge separator using the built-in electric field. however, in a dssc, only the photosensitizer behaves as the electron-hole source generator, whereas the photoanode and redox electrolyte behave as the charge separators. in a dssc, since the dye molecules are tiny, we need to increase ‘dye loading’ or increase the thickness of the dye layer to increase light-harvesting efficiency. dsscs are currently being heavily investigated, and studies on getting them to become more widespread have already been initiated [1]. the usage of quantum dots, solid-state electrolytes and modified electrodes are being considered, along with tandem devices to obtain higher photovoltaic outputs. working principle of a dssc a few essential components of a dssc are mechanical support coated with a conductive material, semiconductor photoanode, photosensitizer, redox electrolyte and counter electrode. tio2 is the commonly used photoanode because of its low cost, wide availability and little to no toxicity. rubased dyes are the common photosensitizers used, and triiodide/iodide is the used redox electrolyte. the working principle is as follows where [2]: • the absorption photon occurs at the sensitizer/photoanode interface. • the electron generated is then injected into the conduction band of tio2. • the injected electron travels through the semiconductor network to reach the back contact, travelling through the external load. • the redox mediator’s role is to regenerate the excited sensitizer, which completes the circuit entirely. figure 1. schematic representation of a dssc however, this is only the working procedure for an ideal dssc. there are some retarding reactions that occur that impact the dssc negatively. recombination effects are one such example. the efficiency of a dssc is dependent on material/layer compatibility and the dye spectral ranges. the surface area and thickness of the semiconductor photoanode can be 3 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 increased to improve dye loading and light-harvesting efficiency. the monochromatic incident photon to current conversion efficiency (ipce) is a property that defines the device's performance. it is defined as the ratio of the number of electrons generated by light in the external circuit and the number of excited photons (function of wavelength). the device's overall efficiency is defined as the ratio of the product of jsc, voc and the fill factor to the intensity of intensity radiation. fill factor (ff) is a value between 0 to 1 that throws light on the losses occurring in the device. the sensitizer and the device's photophysical and electrochemical properties dictate the device's performance. the oxidation potential is what sets the voc value. the electron transfer dynamics set the losses taking place in the cell. the n3 and n719 dyes are the ones that are often used. the carboxylate group is the commonly used anchoring group. it coordinates the dye on the semiconductor surface to immobilize it. since the anchoring group is bonded through a chemical procedure, it is bound to induce water into the device. this, in turn, impacts the long-term stability of the device. hence, to eliminate this problem, it is crucial to have specific hydrophobic units or additives that can resolve this issue. usually, alkyl chains are appended to the bipyridine chain with excellent hydrophobic properties. moreover, these units show a maximum absorption at around 530 nm and display superior stability properties. it is important to note that the recombination effect should be suppressed as much as possible to attain maximum efficiency. the rate of electron transport and the injection process is of utmost importance to the overall efficiency. the excited electrons in the tio2 conduction band have a chance to recombine with the holes in the redox electrolyte to produce dark currents, which can impact the charge collection efficiency. techniques like surface passivation, insulating polymers, adding long aliphatic chains in the tio2 films, and spacer units between the tio2 and dye interface have reduced recombination. this can be because the aliphatic chains join laterally to form a network with the sensitizer, which makes it hard for the triiodide to reach the tio2 surface. recently, supersensitizers have been developed with a photosensitizer with high molar extinction coefficients and hydrophobic properties [2]. examples such as adding thiophene units have excellent spectral absorption properties and shielding of redox electrolytes. as the extinction coefficients of the dye increase, the thickness of the photoanode can decrease. this further increases the voc value, improving performance and thus higher efficiency values. thiocyanate ligands are considered the delicate part of the device because of being a monodentate and ambidentate ligands. there have been studies to replace these ligands but unsuccessful because of shallow pce values. ye05 is a dye developed by researchers with a high spectral response. moreover, the ipce values reach nearly 80% at 600 to 800 nm with high molar extinction coefficients. the presence of the fluorine atoms in the sensitizer modifies the redox potential to yield a jsc = 17 ma/cm 2, voc = 800 mv, ff = 0.74 v and pce = 10.1%. the ye05-based device also shows remarkable stability properties. dsscs are an invention closely related to the natural photosynthesis process. efficiencies between 10 to 15% are easily attainable on a laboratory scale. however, further focus needs to be given to improving the jsc, voc, stability and absorption values which can be improved by studying interfacial dynamics extensively. advantages and disadvantages of dsscs 4 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 dsscs are a third-generation of photovoltaics that have significant advantages compared to the conventional sources of solar cells. however, these devices come with their fair share of challenges which calls for more studies and research [1]. dsscs can work under artificial or low-intensity light sources and effectively under cloudy or shaded conditions. moreover, they can work from unorthodox angles, making them suitable for indoor applications as small-scale devices. the organic and inorganic materials used to fabricate a dssc are very cheap. these further reduce the manufacturing costs compared to other solar cell technologies. the chemicals used in dsscs are highly resistant. they possess mechanical and thermal stability, allowing these devices not rapidly to degrade under full illumination. in some cases, dsscs can even work effectively up to 149 of with negligible efficiency losses. it can be related to dssc's use of a plastic substrate, allowing heat to radiate away quickly. dsscs have a low price to performance ratio, which does not make them suitable for commercialization at this stage. compared to si-based solar technologies, the efficiency is much lower as it mimics the natural photosynthesis process. the recombination effect is very prominent in a dssc device, limiting its maximum performance. lastly, liquid or other common electrolytes can lead to volatilization or leakage, leading to a safety issue. the sensitizer can also be mobilized on the photoanode surface due to poor contact in certain conditions, which further restricts the usage of dsscs. examples of high-efficiency dsscs benzothiadiazole dye for high-efficiency dsscs the best dye-sensitized solar cells (dsscs) are considered highly efficient if they have an average power conversion efficiency (pce) between 10 to 14.2%. dsscs have been comparatively poorly performing compared to photovoltaic technologies like pscs or bhjscs. the stability shown by this particular technology is relatively superior. these stability characteristics can be even subject to variation when non-volatile electrolytes are used. the stability under harsh conditions is improved up to 10 years of long-term performance. moreover, dsscs provide consumers with an aesthetic appeal and lower toxicity. currently, the conventionally used dyes are ru-based dyes. these photosensitizers' expensive and toxic nature calls for alternative and efficient materials. strategies like donor-(π-spacer)-acceptor, organic, electron-withdrawing and chromophores have been used for their unique optoelectronic properties. a previously reported dye using a benzothiadiazole unit (rk1) showed superior stability with a champion pce of 10.12%. in this work, godfroy and coworkers fabricated a dye based on a similar concept to generate a benzothiadiazole-based dye called ykp-88, where the tpa unit and thiophene ring are bridged [3,4]. the ultimate goal of fabricating photosensitizers is to shift the absorption range of the materials towards the visible range. the possible strategy could be to play on the pull-push effect by varying the electron-donating groups, the planarity of the molecules or π-conjugation systems. thus, 4 dyes were produced, namely, ykp-137, mg-207, dj-214 and mg-214. the former 2 dyes were produced by varying the tpa unit with alkoxy groups, and the latter 2 dyes were produced by swapping the benzene spacer with a furan unit. the optical properties of all the dyes are estimated using a dilute solution of dichloromethane. all the dyes show notable absorption in the visible 5 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 range, with molar extinction coefficients varying from 2.7 to 4.33 x 10-4 l/mol cm. the lower energy band is due to internal charge transfer (ict), and the other bands are due to ππ* transition. ykp-137 has a red shift of 28 nm compared to ykp-88. mg-207 has a shift of 3 nm, with the previous molecular changes having no impact on the absorption. however, the shift was more pronounced for the dj-214 and mg-214 dyes due to the furan unit. in this case, using a furan unit improved the planarity of the molecule with nearly 0o in dihedral angle and improved anchoring ability. the furan unit produced an absorption shoulder between 400-450 nm. the dyes showed colors ranging from violet to blue in solution. the absorption spectra were further analyzed by anchoring these dyes on a tio2 layer (2 µm). the absorption spectra widened with a notable blue shift when all the dyes were anchored on the tio2 surface. this is due to the sudden carboxylic acid deprotonation function and the aggregate formation due to a furan unit. the optoelectronic properties of the materials were studied through cyclic voltammetry (cv) measurements. the reversible oxidation potentials for mg-207 and mg-214 are around 0.45 and 0.95 v. ykp-137 is a much easier material to oxidize due to the alkoxy units showing oxidation potentials at 0.28 0.86 v. the homo levels for all the materials were nearly around -5.25 ev except for ykp-137 which was around -5.08 ev. the reduction potential for the ykp-88 and ykp137 dyes are found to be similar, around -1.55 v. these potentials change on varying the πconjugation units. the reduction potentials for mg-207, dj-214 and mg-214 were -1.50, -1.45 and -1.40 v, respectively. the lumo levels for 3 dyes lie in the range of -3.26 to -3.30 ev, and the dye with a benzene spacer has a more negative value. the practical analysis of the energy bands shows that the bands lie for adequate charge transportation between the tio2 and iodine/iodide electrolyte. the dsscs were manufactured and tested using a solar simulator under am 1.5g and 1000 w/m2 irradiation. the devices were manufactured using a liquid electrolyte and an ionic-based electrolyte. thick electrodes are used of approximately 10-14 µm-thick along with 3-4 µm-thick reflecting layers. a thin mesoporous layer of tio2 is used to behave as an anchoring layer, etm and passivating effect. the photovoltaic performances obtained from all the devices were made to be compared with rk-1 as a reference dye. the pce values ranged from 7.01 to 9.78% with liquid electrolytes of low viscosity, with jsc values more significant than 14.05 ma/cm 2. the dyes having a phenyl spacer exhibited better performance than furan spacers. however, the voc values of these dyes were comparatively lower. ykp-88, yk-137 and mg-207 showed voc values equal to 708, 726 and 704 mv, respectively. whereas for dj-214 and mg-214, the dyes were lowered by around 40-60 mv. the highest voc, as expected, was by ykp-137 due to its reduced recombination rate because of the alkoxy chains. the lower voc values can be attributed to the higher recombination rates and the misalignment in the conduction band (lower). as per reports, substituting phenyl-hexyl groups of spiro carbon of the indene unit reduces the dye aggregation. to validate this particular finding, dsscs were fabricated with and without cdca. cdca is an additive/adsorbent that removes the dye aggregates on the tio2 surface. the external quantum efficiencies (eqe) measurements were taken. the derived dyes exhibited a more excellent absorption response at longer wavelengths when compared to ykp-88. moreover, the furan spacer dyes are less efficient in converting photons to electrons, and mg-207 showed the best performance under this criterion. 6 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 the performance of all the dsscs can be reported as follows, the ykp-137 and mg-207 devices with iodine-liquid electrolytes had comparable pces to ykp-88. however, the usage of dyes like dj-214 and mg-214 showed a detrimental impact on the performance of dssc. when the liquid electrolyte was replaced with an ionic-based electrolyte, the jsc values of all the dyes were above 15.4 ma/cm2, with dj-214 and mg-214 dyes having 7.3% efficiency. the furan spacer's device possessed a pce between 6.52 and 7.52% with varying electrolytes. the stability of all the devices was studied when they were exposed to 1000 w/m2 at 65 oc under ambient conditions. the dsscs were encapsulated using epoxy and a uv-absorbing polymer. after 1000 hours, the devices retained nearly 85% of their initial pce. the ykp-88 device retained nearly 80% of its pce after 291 days with a t80 value of nearly 7 years. co-sensitization of dyes is an innovative strategy to improve this photovoltaic technology's pce levels and reliability. the mesoporous tio2 layer was used as an anchor to embed the dyes on its surface to design a co-sensitized device. this strategy can improve voc levels and reduce charge recombination to improve photovoltaic performance further. the dyes used in this case are ykp-88 and ykp-137, which are essentially the same structure but with variations in the alkoxy units. the bulky groups of tpa protect the tio2 surface and further reduces charge recombination of the redox electrolyte. ykp-88/ykp-137 dyes were made to vary in the ratio of 8/2 and 2/8 along with a 5 mm of cdca. the photovoltaic performance of the device is recorded to be jsc of 20.66 ma/cm 2, voc of 745 mv, ff of 71% and pce of 10.9%. it is important to note that the performance obtained from the co-sensitized device was much improved relative to the single dye devices. along with an improvement in jsc, there was a significant improvement in voc, which improved the device's performance. the transient photovoltage (tpv) measurements show that the cosensitized device has a higher charge density when compared to its single-dye counterparts. moreover, the electron lifetimes measured in the co-sensitized device were higher than in the single dye device. the ipce measurements show a correspondingly higher photon-to-electron conversion efficiency and response to the nir region for the co-sensitized device. the devices with 4 different dyes showed reasonable pce between 6.52 to 7.52%, with excellent stability characteristics of nearly 85% retention after 1000 hours. even fabricating a co-sensitized device proves to be an effective tool for developing commercial dsscs. these dyes can be implemented for large-area devices (14 cm2 active area), thus, showing the future of organic dyes in emerging photovoltaic technologies. indoline metal-free dyes for dsscs the conventionally used dyes for dsscs are ru-based dyes, typically reported as n719. there is a pressing need to transition to metal-free-based dyes that are eco-friendly, readily producible, and have suitable photovoltaic properties. the previously reported indoline-based dyes produced specific photovoltaic results. however, the low bandgap and variation in homo, and lumo levels with an increase in methine chain length, produced a redshift in the absorption spectra. in this section, horiuchi and coworkers fabricated 4 dyes with nearly similar molecular backbones under identical conditions [5]. the essential molecular backbone is similar. only a variation in r1, r2 and r3 molecules produced the 4 different dyes, as shown in table 1. 7 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 table 1. molecular structures of indoline 1-4 dyes [5] dyes r1 r2 r3 1 -ch2cooh -ch2ch3 =s 2 -ch2cooh -ch2cooh =s 3 -ch2ch2cooh -ch2ch3 =s 4 -ch2cooh -ch2ch3 =c3s2on-ch2ch3 the absorption spectra of the indoline 1 dye were recorded on a tio2 electrode. the results showed 2 revealing peaks at 526 and 541 nm, respectively. the molecular coefficient for the indoline 1 dye was found to be 68700 m-1cm-1 at 526 nm. these obtained values were much higher when compared to the molecular coefficient of 13900 m-1 cm-1 at 541 nm for n3 dye. in this section, each dye is represented along with the letter ‘n’. the n2 and n3 dyes show similar absorption characteristics to n1, with an absorption peak at 532 and 531 nm, respectively. the more significant number of rhodanine rings on n4 depicted a redshift in its absorption. the colours of the dye also vary from blue to purple to black for the 4 dyes on the tio2 electrode. there was a slight change in absorption range whenever the dye was anchored on the tio2 electrode, indicating some chemical/physical reaction occurring between the dyes and tio2. the dssc device was fabricated using 2 kinds of electrolytes, following the architecture: pt/tio2/dye/electrolyte/fto. here the electrolytes used are lii and 4-tert-butyl pyridine (tbp). a solar simulator recorded the photovoltaic performance at am 1.5 g and 100 mw/m2. the solarto-electric conversion efficiency of all 4 dyes was much higher than other metal-free organic dyes that have been used previously. the ipce measurements showed 85% from 445 to 600 nm for the n1 dye. similarly, n4 dye showed an efficiency greater than 60% in the range from 415 to 510 nm. moreover, these dyes display large photocurrent values with large ipce values. the obtained photovoltaic output parameters are summarized in table 2. table 2. photovoltaic performance of indoline dyes compared to n719 reference dye [5] dye voc (mv) jsc (ma/cm 2) pce (%) ff n1 645 18.75 0.538 6.51 n2 584 17.50 0.538 5.50 n3 628 17.38 0.513 5.60 n4 569 19.56 0.533 5.93 n719 754 16.68 0.657 8.26 additives like cholic acid derivatives such as chenodeoxycholic acid are used to improve n1dssc performance. it has been reported that cholic acid derivatives prevent the aggregation of dye molecules on the tio2 surface. it is shown that n1 dye with a cholic acid additive at an optimal concentration (20 mm) results in twice the better performance. to improve electrolyte composition, 0.05 m of tbp solution was ideal for n1 dssc. moreover, on varying the group iodides used as an electrolyte like lii, nai, ki, cei and (n-butyl)4ni, the lii variant shows the most attractive photovoltaic performance. the optimal performance of the best dssc can be summarized as follows using the following criterion a) n1 dye concentration = 5 x 10-4 m and chenodeoxycholic acid concentration = 1 x 10-3 m b) electrolyte iodide mixture = 0.1 m lii and 0.05 m tbp. on conducting tg-dta analysis, n1-based dssc showed superior thermal stability till 300 oc. it is important to note that the photovoltaic performance obtained from this modification is the highest efficiency value for metal-free organic dsscs without an anti-reflecting layer. 8 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 isophorone dyes for high-efficiency dsscs the most efficient sensitisers are of the d-π-a form. d and a represent donor and acceptor molecules, respectively, and π represents the conjugation system. it is important to note that the d or donor molecules are of utmost importance because they dictate the energy band alignment of the absorber molecule. thus, having a suitable donor molecule can directly impact photovoltaic performance, driving forces, absorption characteristics and spectral properties. the appropriate usage of π-systems can further cause a redshift in absorption. it is essential to highlight that extensive π conjugation can lead to dye stacking on the tio2 surface. the greater the π-stack, the electron injection capability reduces. additives like deoxycholic acid (dca) reduce dye aggregation on the tio2 surface. previous reports have shown how para-bis-substituted aniline was used to modify nkx-based dyes on coumarin derivatives. hara et al. showed how incorporating alkyl chains on oligothiophene units could reduce molecule aggregation and charge recombination probability [4]. like this process, bo liu and coworkers used an isophorone unit for the π-cyclohexene bridge. thus developing 3 dyes, d-3 and 2 reference dyes, d-1 and d-2, here indoline, dimethylphenylamine and triphenylamine units are used as donor molecules, respectively. d-1 and d-2 have decent absorption characteristics, but introducing the indoline unit shows a considerable red-shift with the absorption range broadening in the visible region and the λmax shifted to 497 nm. the molar extinction coefficient of d-3 at λmax is 3.76 x 10 4 m-1cm-1 whereas for d-1 and d-2 dyes, the values are 3.27 x 104 and 2.69 x 104 m-1cm-1, respectively. when these values are compared to n719 dye, the molar extinction coefficient is 1.47 x 104 m-1cm-1 at 535 nm, which is comparatively inferior to d-3. on anchoring the dyes onto the surface of tio2, the λmax is slightly blue-shifted. the adsorption threshold is shifted by more than 50 nm from 650 nm to 700 nm. these can be attributed to the interaction of the carboxylate group with tio2. the lumo levels of the dyes are calculated and found to be -0.71, -0.84 and -0.85 v for d-2, d-1 and d-3, respectively. these values are more negative than the cbm of tio2, which allows effective and suitable electron injection. the orbital energies were also calculated using a hybrid density functional theory where the lumo energies were found to be -2.15, -1.98 and -2.16 v for d-1, d2 and d-3 dyes, respectively. the best performing (d-3) device was fabricated with and without dca to validate the phenomenon of dye aggregation. on adding 1.0 mm of dca solution to an acetonitrile solution of d-3, the photocurrent decreased from 14.76 to 11.07 ma/cm2. these values show that there was no significant π-aggregation for the d-3 dye. the reasons for this can be multiple such as the twisted isophorone unit, an indoline unit, non-planar ground state geometry, and the two methyl groups in the isophorone unit contribute to the steric hindrance of the molecule. from the above reasonings, the d-3 dye generally prevents close π-π aggregation. the performance of devices is analyzed with varying thickness of tio2 electrodes. the thickness used in this particular scenario is 2.2, 3.4, 3.8, 5.0 and 6.7 µm. although the ff values remained constant in all cases, the jsc values increased from 11.19 ma/cm 2 to 18.63 ma/cm2. however, the voc values decreased with the increasing thickness of tio2. this can be attributed to the increase in the tio2 area, which provided a higher charge recombination probability. the usage of thick tio2 did not permit much light permeation into the device, which further prevented charge excitation and thus led to lower voc values. this counter-current effect generated a nearly constant value of pce, with a maximum pce of 7.41% at 5.0 µm. the ipce spectra of the 3 dyes are analyzed concerning n719. the high absorption properties in the broad region produced a higher efficiency value for d-3 than d-1 and d-2, which exceeds 80% in the range of 430-630 nm. this value reached a maximum efficiency of 89% at 508 nm. the integrated short-circuit current 9 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 obtained is nearly 18.63 ma/cm2. it is important to note that the conversion efficiency values obtained for the d-3 are much higher than in the case of n719. the performance of the d-3 dye-based device can be summarized as follows: jsc of 18.63 ma/cm2, voc of 634 mv, ff of 0.63 and pce of 7.41%. when comparing this performance for the n719-based device, the jsc value was only 15.60 ma/cm 2 with a pce of 7.03%. thus, we can firmly conclude that in a d-π-a system, the d atom plays a vital role in determining the photophysical, electrochemical and photovoltaic performance of the device and film produced. moreover, the results that are produced through these molecular configurations are higher than conventionally used dyes, which provides researchers with a potential commercial candidate. porphyrin sensitizer for 14.2% dssc the molecular structure of the dye predominantly dictates the performance of a dssc. conventionally, ru-based dyes have been used, but organic sensitizers and zn-porphyrin complexes have dssc implications with recent innovations. yao et al. showed how a dithienopicenocarbazole organic dye (c281) could produce a pce of 13% in the presence of co(bpy)3 2+/3+ electrolyte. similarly, kakiage et al. produced a pce of 14.34% using a co-sensitized device with adeka-1 and leg-4 using co-adsorbents like co(phen)2 2/3+ electrolyte. however, it is essential to note that pce levels are just one aspect of commercial dsccs. it is essential to understand that factors like long-term stability, cost efficiency, material availability, and novelty are essential too. the d-π-a has been the most widely regarded photosensitizer configuration due to its efficient intramolecular charge transfer (ict). increasing research has been going on that requires the discovery of novel and new d and a molecules along with π moieties. the dyes used in the works of jung-min ji and coworkers highlight asymmetric thieno[3,2b]benzothiophene moiety and 4-hexyl-4h-thieno[3,2-b]indole (hxti) moiety into dye backbone as new π-bridges [6]. the dyes referred to in this particular case are sgt-130 and sgt-137. in addition to this, 4 different fluorene-based donors are studied, namely, fa, hfa, dfa and bbfa, to produce dyes referred to as sgt-146, sgt-147, sgt-148 and sgt-149. the uv-vis absorption measurements of the sgt sensitizers are analyzed in thf solutions. the dyes show two distinct absorption bands around 360-400 nm that account for the π-π* transition of the d molecule, whereas the second band between 500-600 nm is due to the ict between d and a. the maximum absorption wavelength (λabs max) of nearly all the dyes is red-shifted with maximums at 343, 377, 380, 381 and 389 nm for sgt-137, sgt-146, sgt-148, sgt-147 and sgt-149 dyes respectively. by comparing the above values, we can clearly conclude that the fluorene donors show a significant red-shift in values, even reflected in the λmax, abs values. thus, we can conclude that the usage of fluorene can improve the light absorption capacity at shorter wavelengths. the conjugation length in the d moiety also significantly impacts the molar extinction coefficient by giving a more extreme value. the fluorene unit has improved the intramolecular electron push-pull effect on the d-π-a unit. the cv results of the sgt dyes show a calculated value for the first oxidation potentials (eox) as follows, 0.86, 0.77, 0.77 and 0.84 v for sgt-146, sgt-147, sgt-148 and sgt-149 dyes respectively. the first quasi-reversible oxidation corresponds to the homo levels following the trend bbpa < fa < bbfa < hfa ≈ dfa. the sgt sensitizers have energy bands sufficiently higher than liquid electrolytes (co(bpy)3 2+/3+ and ionic electrolytes like i-/i3 which is thermodynamically favourable. moreover, a similar alignment can be observed in the lumo levels of the sgt dyes, which are placed above the tio2 10 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 conduction band, which ensures beneficial electron injection properties. on calculating the dihedral angle of the dyes, all the sgt dyes showed a similar value between the d and hxti units. the value was found to be nearly equal to 42o. it is important to note that the bbfa has a rotatable dialkoxy phenyl unit with the dihedral between the fluorine and dialkoxy unit 42o. the homo level is delocalized among the hxti π-bridge and the d unit. the homo-1 level extends to the btd-phenyl unit, and finally, the lumo level extends to the a unit. some visible overlapping effects may be observed related to the ict between d and a units to indicate effective charge transfer and separation. it is important to note that the theoretical values of homo/lumo levels, absorption spectra and donor strength (bbpa < fa < bbfa < hfa ≈ dfa) match very well with the experimental values. replacing the bbpa unit with fa, bbfa, hfa, and dga increases the homo-1 orbitals by 2 times, and the π-bridge contribution to the homo-1 orbital is decreased. on decreasing the planarity of the d unit, there is a significant red-shift observed. however, there is a consequent decrease in ict intensity. the photovoltaic output parameters were analyzed using 2 redox electrolytes under am 1.5 g (100w/m2) with a metal mask of 0.041 cm2. the volume ratio varies concerning solvents, coadsorbents, counter anions, and dye concentration. to determine the optimum performance of a dssc device. on varying the unit from biphenyl to fluorenyl, the solubility levels changed, which further impacted the volume ratio of the dipping solvents. these produced lower pce levels for sgt-137. the pce levels of the sgt device with cdca is 9.5%, 3.6%, 8.0%, 7.9% and 11.2% for the sgt-137, sgt-146, sgt-147, sgt-148 and sgt-149 dyes respectively. on changing the coadsorbent from cdca to hc-a1, the pces of the dyes further changed to 10.0%, 9.3%, 9.6%, 10.0% and 10.3%, respectively. analyzing the sgt-146 dye individually, we can see a dramatic increase in pce when the coadsorbent is changed to hc-a1 because of the alkyl chain absence in its donor unit. the counter anion was also changed from (b(cn)4) to tfsi, where all the sgtdyes showed an increase in pce values (> 10%). the best pces were obtained from devices using hc-a1 coadsorbent, co(bpy)2/3+ redox electrolyte and etoh/thf dipping solvents. for the co(bpy)2/3+ electrolyte, the pce’s are as follows: 10.5%, 10.2%, 10.5%, 10.6% and 11.4% for sgt-137, sgt-146, sgt-147, sgt-148 and sgt-149 dyes respectively. the best performance was obtained from the sgt-149-based dssc. this had a bbfa donor with a voc = 0.909 v, jsc =17.6 ma/cm2 and ff = 73.2% with an hc-a1 as a coadsorbent. the excellent performance of this dye can be attributed to the bulky nature of bbfa, high molar absorptivity and dye absorption amount. thus, it is reasonable to conclude that as the nature of the bulky substituent decreases, the voc decreases. the jsc values increase in a trend, 16.39, 16.67, 17.15, 17.12 and 17.49 ma/cm2 for sgt-137, sgt-146, sgt-147, sgt-148 and sgt-149 based dyes respectively. the ipce spectra can also be correlated to the performance of the device. similarly, devices with low jsc values showed a low ipce value, and the sgt-149 dye with the highest jsc showed a high ipce value. sgt-137, sgt-147 and sgt-148 have similar absorption ranges. on varying the electrolyte to i-/i3 -, the jsc value for sgt-137, sgt-146, sgt-147 and sgt-148 was 18.4-18.7 ma/cm2. the highest jsc (19.32 ma/cm 2) was for sgt-149 dye. on conducting a light-soaking test with devices containing both the electrolytes, most devices retained 84-88% of their initial pce after 1000 hours of light soaking. the trpl measurements were taken on tio2 and al2o3, where the decay lifetimes were 27.3, 27.5, and 22.7 ps for sgt-146, sgt-147, sgt-148, sgt-149 dyes, respectively, on tio2. similarly, on al2o3, it was found to be 429.5, 286.9, 335.9 and 327.2 ps. the electron injection efficiency ηinj values are 93.6, 90.3, 93.5 and 92.4%, respectively. the eis measurements are taken and the co(bpy)3 2+/3+ based dsscs had a rrec values of 22.41, 29.03, 29.61, 34.07 and 72.59 ω for sgt146, sgt-137, sgt-147, sgt-148 and sgt-149 dyes 11 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 respectively. these values correspond very well with the trend seen in voc values. even the tr and cµ values followed the same trend as the rrec values. the tr values were 17.4, 17.9, 18.1, 18.9 and 22.7 ms, which is by the voc and rrec values. the ηcol values were found to be 78.6%, 75.8%, 78.7%, 78.8% and 83.7% for sgt-137, sgt-146, sgt-147, sgt-148 and sgt-149 dyes respectively. a similar tr and rrec values trend are seen for the i -/i3 electrolyte-based dsscs. the cµ values were found to be in the order sgt-146 < sgt-147 ≈ sgt-137 < sgt-148 < sgt-149. the ηcol values from eis were found to be 78.6%, 75.8%, 78.7%, 78.8% and 83.7% for sgt-137, sgt-146, sgt-147, sgt-148 and sgt-149 respectively. these results show that sgt-149 (bbfa) has the best characteristics for efficient dsscs, which produce high voc because of the bbfa unit and a high jsc unit because of the umbrella effect. a strategy was then used to develop a co-sensitized device using a porphyrin-based dye (sgt021) and sgt-149. the necessity for employing sgt-021 is to compensate for the weak absorption properties of sgt-149 in the range of 430-510 nm and 680-800 nm. two devices were fabricated using co(bpy)3 2+/3+ and i-/i3 electrolytes. using the former electrolyte, the photovoltaic parameters obtained were, pce = 14.2%, voc = 0.919 v, jsc = 21.06 ma/cm 2 and ff = 73.4%. using the latter electrolyte, the photovoltaic parameters obtained were, pce = 11.6%, voc = 0.738 v, jsc = 22.25 ma/cm 2 and ff = 70.9%. the iratio for sgt-021 and sgt-149 is 1:3 and 1:3.5 for cobalt and iodine-based electrolytes. on analyzing the ipce spectra, the weak absorption properties of sgt-149 are compensated by sgt-021, which is reflected through the high jsc values. the rrec, tr and ηcol values for the co electrolyte are 69.8 ω, 29.23 ms and 98.5% and for the iodine electrolyte are 22.98 ω, 670.3 ms, 90.1%, respectively. the high voc values can be justified through the favourable rrec and tr values, whereas the high ηcol justifies the high ipce value. on analyzing the co-based co-sensitized dssc under am 1.5 g at 50 oc, the device retained nearly 80-83% of its initial pce after 1000 hours of light-soaking. this particular study analysed how 4 new hxti-organic dyes using the d-π-a configuration can help generate efficient dsscs. moreover, incorporating fluorene-based substituents further improved the stability of the dssc under light-soaking tests. lastly, the co-sensitization of suitable dyes (sgt-021 and sgt-149) led to a substantial increase in voc and jsc to produce devices with more than 10% pce levels which is a suitable candidate for commercial applications. robust organic dye for stable and efficient dsscs a suitable and appropriate dye is essential as that is the critical component that generates charge carriers and permits the suitable transportation and injection of electrons. it is also essential to regulate the tio2/dye/electrolyte interface as a rough or incompatible interface can increase interfacial recombination. thus, it is necessary to investigate suitable dyes on a laboratory scale and examine the possible mechanisms to scale such technologies. the conventional ru-based sensitizers are not earth-abundant, raising the cost of the device. moreover, some ru-complexes with a broad absorption range often show modest molar extinction coefficients, limiting the device's performance. looking into organic sensitizers is of great importance because of their lower costs, more accessible synthesis, larger extinction coefficient values and reasonable stability values. metal porphyrins are a good option, but the complex synthesis procedure, low product yields, and difficulty anchoring require less complex approaches. in this section, damien joly and coworkers synthesized a dye known as rk1, which follows a simple 5-step synthesis process from low-cost precursor solutions [7]. the main aim was to use a dissymmetric πconjugated bridge with alkyl chains, electron-deficient groups, and an electron-rich group. 12 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 the thiophene btd phenyl chromophore implies the π-bridge corresponding to the d-π-a configuration. taking the uv-vis absorption measurements, the rk1 sensitizer shows two significant absorption bands. firstly, the one located in the uv region can be attributed to the ππ* transition corresponding to the aromatic rings. secondly, the one located in the visible region can be attributed to the ict transition between electron-donating and withdrawing groups of the entire sensitizer molecule. the measurements of these devices were done regarding n719-based conventional dye. the molar extinction coefficient of rk1 is twice as high as n719 at 470 nm, which is also responsible for its orange color. the cv measurements show that the first oxidation peak is at 0.98 v and the second oxidation peak is at 1.41 v. the first oxidation peak can be attributed to the oxidation of the triphenylamine unit, and the second oxidation peak can be attributed to the oxidation of the π-backbone. the experimental homo and lumo levels are 0.93 and -0.72 v, respectively, with a bandgap of 1.65 ev. it is important to note that the lumo level lies above the tio2 cb, and the humo level is aligned well with the electrolyte. these ensure effective electron injection and reproduction of dye. the electron density distribution is predicted using density functional theory. the result shows that the homo levels are delocalized on the triphenylamine and thiophene groups of the π-conjugated bridge. the lumo levels are delocalized on the btdphenylvinylcyanoacetic unit. this result is essential to understand that the directional electron distribution helps in electron injection into tio2 and regeneration of dye by quicker reduction of the i-/i3 dye. dssc using the rk1 dye is fabricated using an acetonitrile electrolyte. the electrodes used in this case is a double-layer structure, firstly, mesoporous tio2 followed by a tio2 scatter layer. the n719-based dssc is used as a reference in this case as well. the iv curves are recorded at a standard illumination of am 1.5, 1 sum illumination along with ipce measurements. to determine the device's optimal performance, the thickness of the tio2 film is varied from 4 to 13 µm. the scattering layer of tio2 varying from 3.5 to 4 µm is deposited. the concentration of the dye from 0.2 to 0.5 mm is varied and used along with a coad sorbent of chenodeoxycholic acid. using chenodeoxycholic acid improves dye loading characteristics and reduces the formation of dye aggregates on the tio2 surface. it is important to note here that, even at a low film thickness of tio2, the device's performance remains above 7% pce. on further increasing the thickness of the tio2 film, the jsc increases to 20.25 ma/cm 2 to produce a champion pce of 10.2%. the performance of the rk1 and n719-based devices are nearly similar, with pce values greater than 10% with similar dark currents. the photocurrent measurements from the ipce spectra show that n719 performs relatively better than rk1 at longer wavelengths, whereas rk1 performs relatively better than n719 at shorter wavelengths. the transient photovoltage measurements are also analyzed. the charge extraction data for both the dyes are analyzed, and as expected, the rk1 dye shows a better response than n719. on calculating the electron lifetime constant, n719 dye showed a higher value than rk1. however, we can confirm with previous literature that such a phenomenon is very much observed in organic sensitizers. the lower voc value for rk1-based devices can be related to the lower-lying tio2 cb and reduced electron lifetime constant. to measure the long-term stability of the device, volatile solvents like acetonitrile cannot be used. hence, in this case, a solvent-free ionic liquid electrolyte is used for thermal stress and long-term stability studies of rk1-based devices. two different electrodes are used: firstly, a standard 13 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 mesoporous tio2 electrode and a tio2 paste, which improve light-harvesting efficiency. with an 8 µm thick tio2 film and a 3.5 µm thick reflecting layer, the resultant photovoltaic performance is a jsc of 15.40 ma/cm 2, voc of 0.665 v, ff of 69% and pce of 7.36%. the light-soaking test is conducted under a light intensity of 1000 w/m2 at 65 oc. on conducting the test, the pce significantly increases. this phenomenon can be related to the increased penetration of the electrolyte and electrode activation. however, after 2200 hours, the pce shows a notable linear degradation in pce. after the devices are analyzed for 5000 hours, they retain nearly 75% of their initial pce. through this work, we understood the usage of a simple sensitizer with an uncomplicated synthesis process, and low-cost precursors were capable of producing highly efficient devices using a novel approach. moreover, the fabricated devices displayed enhanced stability even after 5000 hours with a slight loss in pce, which paves the way for a future stable, inexpensive and efficient device. molecular photosensitizer with 1.24 v as voc the notable advantages that dsscs offer over other solar technologies are the capability to produce light-harvesting properties through both faces of the solar cell, aesthetic appearance, and inexpensive fabrication and synthesis procedures. moreover, the same benefits of these devices have led to smallor large-scale implementations like the swisstech convention center and the science tower of graz. an alternative way to boost a photovoltaic device's performance is to improve its voc significantly. it has been shown that organic dyes, when paired with cu(ii/i) electrolytes, exceed a voc of 1.0 v. these values are comparatively higher when analyzed to the cobalt or iodine-based electrolytes. dan zhang and coworkers developed two dyes using this approach, referred to as ms4 and ms5. the ms4 dye uses a donor unit of n-(2’,4’bis(dodecyloxy)-[1,1’-biphenyl]-4-yl)-2’,4’-bis(dodecyloxy)-n-phenyl-[1,1’-biphenyl]-4-amine and acceptor of 4-(benzo[c][1,2,5]thiadiazol-4-yl) benzoic acid (btba). ms5 uses a similar arrangement [8]. however, in the case of the donor atom, on increasing from n-hexyloxy to ndodecyloxy, the ms5 dye is generated. the performance and properties of the dyes are compared with a reference dye nt35 that has the same donor unit as ms4, but the acceptor unit is cyanoacrylic acid (ca). the uv-vis absorption spectra for the dyes are recorded on a 2.2 µm thick tio2 electrode. ms4 shows a red shift by 46 nm compared to nt35, with a maximum absorption wavelength of 468 nm. the ms5 sensitizer also shows a similar absorption spectrum to ms4. the molar extinction coefficient of nt35 in the 400-500 nm range is nearly 5 and 3 times larger than ms4 and ms5 dye, respectively. however, the maximum absorbance of nt35 on tio2 is only 1.5 times larger. this indicates that nt35 has a very loose molecular packing on tio2. the dye loading amounts on tio2 are measured to be 2.6 x 10 -9, 5.3 x 10-9 and 6.9 x 10-9 mol cm-2 µm-1 for nt35, ms4 and ms5 dyes, respectively. on conducting the cv tests, the eox results show 1.21, 1.17 and 1.18 v on tio2 for nt35, ms4 and ms5 sensitizers, respectively. analyzing the values, having a more positive value than nt35 shows the suitable capability for dye regeneration. the zero-zero transition energies (e0-0) on tio2 film are 2.48, 2.29 and 2.28 ev for nt35, ms4 and ms5, respectively. we can conclude that having a btba acceptor unit further reduces the energy gap for both ms4 and ms5. the ered values show a value of -1.27, -1.12 and 1.10 v for nt35, ms4 and ms5, respectively. similarly, having more negative values facilitates suitable electron injection from the sensitizer to the tio2 cb. 14 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 the devices fabricated used three sensitizers, particularly as [cu(ii/i)(tmby)2] coupled with tfsi, litfsi and nmb in acetonitrile. the ipce is determined for each of the device sensitizer equivalents. ms4 and ms5 have a near 50 nm red shift compared to nt35. the maximum ipce value shown by ms4 and ms5 is nearly 82% at 510 nm, which is superior to nt35, having 75% at 400 nm. the energy offset levels between the dye/electrolyte and dye/tio2 interface provide a method for proper dye regeneration and electron injection. the higher ipce value also indicates the improved charge collection efficiency. moreover, the transient photovoltage measurements show that ms4 and ms5 devices have longer carrier lifetimes than nt35. the nt35-based device showed a photovoltaic performance: voc of 0.95 v, jsc of 5.96 ma/cm 2, ff of 0.791 and pce of 4.5%. the ms4-based device showed a performance of voc of 1.17 v, jsc of 8.86 ma/cm 2, ff of 0.73 and pce of 7.6%. the ms5-based device showed a performance of voc of 1.24 v, jsc of 8.87 ma/cm2, ff of 0.73 and pce of 8%. the maximum voltage obtained using a [cu(ii/i)(tmby)2][tfsi]2/1 electrolyte is 1.37 v. the voc difference between the ns5-based device and the maximum voltage recorded can be accounted for by the recombination effect taking place. on calculating the ideality factors, the ms5-dssc showed the lowest value of 1.08 than ms4 and nt35. this indicates the reduced recombination that ms5 depicts and its reduced trap states. on conducting transient photovoltage decay measurements, an indefinite number of charges are being withdrawn from the tio2 film after a certain photovoltage, indicating that dye changes do not necessarily impact the conduction band and trap states. ms4 has twice the magnitude of its nt35 counterpart, whereas ms5 has a three times manifold. the dye loading is more profound in the ms4 and ms5-based devices, implying reduced charge recombination. the co-sensitized dye used in this case is a dye referred to as xy1b for its superior spectral response along with ms5. the absorption spectra of ms5 and xy1b complement each other, enabling the device to have a broad spectral response. the ipce spectrum of the xy1b and ms5 devices is higher than its counterparts. an xy1b-based dssc produced a photovoltaic performance of, voc of 1.01 v, jsc of 15.26 ma/cm 2, ff of 0.763 and pce of 11.8%. the cosensitized device produced higher values with a voc of 1.05 v, jsc of 15.84 ma/cm 2, ff of 0.813 and pce of 13.5%. moreover, on conducting a light soaking test to evaluate the stability of the device, it retained nearly 93% of its initial pce after 1000 hours of soaking at 45 oc. the jsc loss of the co-sensitized device is only 6% which is lesser than half of the xy1bcounterpart. this reduced jsc loss can be attributed to the improved absorption spectral response and higher ipce values. the dsscs anchored on tio2, and the electrolyte of litfsi and nmb in acetonitrile show a time constant (from tio2 to d +) value of 49 and 61 µs for xy1b and the cosensitized device, respectively. the regeneration lifetime of the d+ with the electrolyte is found to be 5.7 and 6.0 µs, respectively, for xy1b and xy1b + ms5. the regeneration efficiencies are 86.4% and 91.0% for xy1b and the co-sensitized device, respectively. the improved dye regeneration ability is partly responsible for the lower jsc losses and high ipce values. the voc losses are 26.0% and 23.7% for xy1b and co-sensitized devices. this result indicates how the latter device possesses reduced charge recombination in bulk and the device's interface. the dye loading amount for the co-sensitized part is 2.70 x 10-8 mol cm-2 µm-1, which is significantly higher than the individual counterparts, thus, retarding the recombination effect. the ideality factor for the co-sensitized device is also lower (1.27) than xy1b (1.41) and ms5, respectively. the fftl loss is also significantly lower (4.8%) than the xy1b counterpart (6.4%), further reducing the recombination effect. the ff losses are also calculated and found to be 9.4% and 5.8% for xy1b and the co-sensitized device, respectively. 15 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 the co-sensitized device shows how reduced charge recombination can impact performance and how a low ideality factor can influence a device’s charge transporting properties. the cosensitized device with an active area of 2.8 cm2 was made and tested under an osram 930 warm white fluorescent tube to investigate the device's optimum performance further. the experimental energy gap was calculated to be 1.73 ev, giving a pce of 49%, 51%, 54% and 57% under a light intensity of 100, 1000, 10000 and 314, 465 lux, respectively. the device is fabricated with a reduced concentration of cu (ii) electrolyte, as studies have shown how a reduced amount of cu (ii) electrolyte can minimize charge recombination to improve further voc and performance of the device, particularly under ambient light. a similar principle can also be used in the case of cu (i). the device's performance is recorded at 1000, 500 and 200 lux. at 1000 lux, the device performs remarkably, with a voc of 0.98 v, jsc of 138.2 µa/cm 2, ff of 0.815%, pce of 34.5% and a pmax 109.8 µw/cm 2. a considerably high pce value was also obtained for higher device areas, 31% and 26% at 1000 lux for 8 and 20.25 cm2, respectively. it is essential to highlight that the devices also performed significantly well under 200 and 500 lux with a voc above 0.92 v, pce between 32-33% and an ideality factor of 1.25. the pce levels obtained from this particular configuration and engineering are surprising and a feat because such levels even exceed many of the current pscs, si-based solar cells, cigs, and gaas solar cells. this study analysed how molecular engineering and careful usage of donor and acceptor units can suitably tailor the pce levels for cu-based dsscs. moreover, the improved pce levels can be attributed to the reduced ideality factor and minimal charge recombination effect. the impact of photovoltaic performance can also be related to the influence of cu-redox electrolyte on the device. mose2/mo counter electrodes for efficient dsscs for traditional dsscs, the counter electrode (ce) used is pt. however, it is essential to note that as commercialization of these devices occurs, we need to choose cheaper and more viable materials that reduce the cost of the device. several possible candidates have been considered previously, like metal oxides, sulfides, nitrides, and carbon-based materials. selenides have been studied extensively for their interesting optoelectronic properties previously used in solar cells and photocatalysis. however, the series resistance of these devices (rs) is exceptionally high, leading to reduced ff and performance. this can be related to the poor contact between the ce and substrate. in this section, haijie chen and coworkers designed a bilayer ce structure using mose2/mo [9]. the top mose2 layer acts like the i3 reduction site, and the bottom mo layer acts as the charge collector for extracted charges. the preparation method is a mo thin film on the substrate. the electrical conductivity of the mo film is exceptionally high, with a value of 28.1 µω cm. the mo-based glass is annealed in an atmosphere of se to form a bilayer of mose2/mo at 500 oc for 30 mins. the resultant surface is found to be homogeneous with a smooth morphology. on conducting an xrd analysis, the mo peaks are present, which shows the presence of mo in the bilayer configuration. the crosssectional sem measurements show a bilayer structure with a 770 nm thick mo layer and 558 nm thick mose2 layer. on doing an eds line scan result, se was not in the bottom layer, whereas the upper layer showed a liner distribution of se across the mo surface, indicating good contact between the 2 layers. the fermi level of mose2 and mo are nearly equal, and if the energy band of mose2 upsweeps, a high conductive region is formed, which facilitates charge transfer. 16 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 on fabricating a device with the architecture of mose2/mo ce, the jsc obtained is 15.07 ma/cm 2, voc of 0.805 v, ff of 0.67 and pce of 8.13%. the obtained photovoltaic performance is comparable with pt-based ce with a jsc of 16.11 ma/cm 2, voc of 0.794 v, ff of 0.63 and pce of 8.06%. it is essential to understand that a thin layer of mose2 is insufficient to reduce i3 whereas a thick mose2 layer creates a lot of series resistance and is not suitable for charge transfer. thus, it is vital to understand the optimum layer of mose2, which is found to be 558 nm. the cv measurements are taken, and the pt and mo-based ce have two pairs of redox and cathodic peaks that correspond to the two-step reduction process of i3 -. the mose2/mo ce has a higher charge/current density, improving charge transport, making it a plausible candidate for ce to replace pt. the eis measurements of both the ces are taken. there are 2 semi-circles formed at low and high-frequency regions, respectively. the high-frequency semi-circle is related to the iodine reduction and its charge transfer resistance. the semi-circle in the low-frequency region is related to the series resistance. here rs is attributed to electron collection from an external circuit. the rs value for the mo-based electrode is 2.64 ω, whereas for the pt-based electrode is found to be 15.98 ω. the rct is related to the charge transfer resistance between the electrolyte/ce interface. the rct values are 0.30 ω for mose2/mo and 8.95 ω for pt. this study showed how mose2/mo ce could be prepared by an in-situ process using a bilayer structure. moreover, the analysis showed how cv, eis and photovoltaic performance for mobased ce improved the device compared to pt, which is much more superior. this configuration was also reflected on a bifacial cigsse solar cell. compared to previous lectures, the obtained rs and rct values, in this case, are much lesser than the reported values, making it an even more beneficial candidate for ces. hot-bubbling sno2 with tio2 for efficient dsscs a dssc with tio2 photoelectrodes have suffered from low electron mobility, sluggish responses and, in some cases, increased charge recombination. materials like nb2o5, zno, sno2 and bifunctional materials have been explored as suitable alternatives. in particular, sno2 has grabbed much attention because of its high electron mobility and larger bandgap with a more minimum value of cb minimum than tio2, facilitating suitable electron injection and transfer. however, the lower voc values of sno2-based devices can be attributed to the recombination process and position of the cb. in this section, we shall explore the works of xiaoli mao and coworkers, who developed a high crystalline phase of sno2 which can reduce recombination and align the energy band suitably [10]. this was possible through a method called hot-bubbling synthesis, through which the size of the sno2 crystals could be controlled, and desired sizes could be obtained. homogeneous nucleation rates and sites were observed because of the gases' high-temperature processing and fast diffusion rate. the hot-bubbled sno2 formed was highly crystalline in nature through this fabrication method. after a prolonged growth time, the sno2 clusters did now grow. this indicates that sno2 has a high-energy barrier in hot oa-ode-ola solutions. the xrd analysis shows the presence of a tetragonal sno2 molecule. the xrd results show multiple patterns, where the strong patterns can be associated with tio2, whereas the weaker patterns can be associated to the tem results depict semi-spherical sno2 particles with diameter ranges from 3.0-4.0 nm. under hrtem, lattice fringes were observed, showing the high crystallinity of sno2. the fringe distances were found to be 0.142 and 0.330 nm. the tem results show how sno2 is well-dispersed in the composite film, 17 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 and the hrtem results show the close and well-formed packing between sno2 and tio2. comparing this to the traditional method of synthesizing sno2 through a hydrothermal method, the average diameter is 20 nm. this sample is referred to as s_20. it was not possible to use sno2 entirely as a photoelectrode. instead, this was mixed with commercial tio2 composites in different ratios. the ratios vary from 0 to ∞. the porous nature of all the anodes is visible. however, the s7.5 showed the most excellent porosity distributed across the film homogeneously. the mixed particle size of sno2 and tio2 forms a cohesive valuable network for a photoanode. these analyses depict the compatibility between sno2 and tio2. the ft-ir spectra show the broad absorption range of sno2/tio2 composites in 400-800 cm-1, related to the ti-o-ti bonds. the maximum at 1063 cm-1 in s7.5 and s12.5 can be related to the sn-o-sn bonds. the highest absorption is seen in s12.5, which can be related to the uniform distribution of sno2 in tio2. the n2 absorption-desorption spectra isotherms of varying sno2/tio2 composite films can be studied in table 3. table 3. n2 absorption-desorption results of the composite films [10] film type dye loading (10-7 mol cm-2) surface area (m2 g-1) pore volume (cm3 g-1) pore size (nm) s0 1.70 45.4 0.22 28.4 s7.5 1.90 53.0 0.27 20.5 s12.5 1.57 53.6 0.25 18.7 s∞ 0.71 64.8 0.06 3.9 from the n2 absorption-desorption results, we can see that, on incorporating sno2 in small amounts to tio2, the surface area increases, a valuable property for photoelectrodes. the improved dye loading ability can also be noticed when adding sno2 to tio2. the uv-vis absorption spectra of the samples are recorded. s7.5 shows the highest range of absorption spectra with a considerably higher dye loading than the rest of the film types. the loading can be related to the pore volume and surface area, and thus, adding sno2 to composite tio2 can increase n719 loading. however, increasing the sno2 amount past a specific optimum value, the pores are sealed, and dye loading decreases. using a mixture of tio2 and sno2 decreases the interfacial resistance of the device. as a result, the charge mobility of the device increases. on adding sno2, the charge incorporation increases a lot, and in the case of s7.5, the effect between sno2 and tio2 compliment each other the most, which improves charge transfer. in this case, the addition of sno2 shifted the cb minimum in a favorable manner which genuinely makes this feature an additive for improved ipce and photoelectrodes. on recording the photovoltaic parameters, the addition of sno2 reduced the voc value from 0.82 to 0.79 v. however; the jsc value increased significantly from 8.2 to 15.4 ma/cm 2. the pce value was 6.7% (s7.5) higher than a modification done by cao et al., tio2 coated with sno2 hollow microspheres. the eis measurements show double semicircles in small and high-frequency ranges. the rs values vary from 10.8 to 22.3 ω m 2. the s7.5 has a lower value for rs which indicates the improved ohmic contact of the photoanode. a smaller value for rct (charge transfer resistance) was also obtained for s7.5 (25.3 ω cm2). however, the r1 values are nearly equal. the reduced rct values can be attributed to the faster charge transfer and mobility from the 18 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 electrolyte to the photoelectrode. it is essential to note that, on adding sno2 to tio2, there is a notable increase in surface area, which possibly improved the photovoltaic performance. however, on adding more sno2, the photovoltaic performance begins to decrease, indicating an optimum ratio for sno2 and tio2 for improved performance. the electron transport and recombination phenomenon at the interface are studied through imvs and imps. the electron transport time (td) is 3.99, 1.26, 1.12, 1 and 317.47 ms for s0, s5, s7.5, s12.5 and s∞ films. these values were highly reduced when compared to a pure tio2 commercial photoelectrode. moreover, the recombination time constant (tr) is increased, indicating the reduced recombination in the case of sno2/tio2-based photoelectrodes. the charge collection efficiency (ηcc) was calculated, and the highest efficiency value recorded was 99.7%. hence, this analysis shows that incorporating sno2 reduced charge recombination and improved electron transport and mobility. the reduction in voc value is not yet known, but possible reasoning can be developed with further evidence. through this work, the modification of sno2 with tio2 produced a photoanode with suitable energy band alignments, reduction in trap sites, provides more charge transfer pathways, improved electron transfer and mobility, more excellent conductivity, and higher electron diffusion lengths, which can be reflected through the photon-to-electron conversion efficiency. co-polymer gel electrode for a high-efficiency dsscs commercialization of dsscs requires the usage of suitable electrolytes and solvents such as acetonitrile and 3-methoxypropionitrile (mpn). however, these solvents possess issues like volatility and fluidity, which can impact the long-term performance of the device. recently, gelbased electrolytes have been incorporated into devices, and the performances obtained are comparable to their liquid electrolyte counterparts. amongst the gel-based electrolytes, polymer gel electrolytes follow a simple preparation method and have an excellent liquid trapping capability. chen et al. reported the usage of in-situ gelation of pan-va and acetonitrile-based electrolyte with an efficiency of 9.5% using a tio2 nanofiller. other than the i -/i3 redox couple, the cobalt (ii)/(iii) redox couple are non-corrosive and do not depict any visible region light absorption properties. in this section, wanchun xiang and coworkers used a cobalt gel electrolyte with a varying amount of (4-10%) pvdf-hfp in acetonitrile. the influence of a polymer-based gel electrolyte is analyzed, and the photovoltaic performance is studied [11]. the rheology results show that even a 4wt% of pvdf-hfp produces a gel matrix. the gelation time required is dependent on the polymer content. it varied from 5h for 4wt% to 30 min for 10 wt%. the devices fabricated used a 6 µm thick tio2 electrode. the devices used an mk2 dye, and on using 4wt% of the polymer, a pce of 8.7% is measured. it is important to note that this recorded pce is the highest value noted for a co-based redox couple. the jsc, voc and ff values are 884 mv, 13.9 ma/cm2 and 0.71, respectively, under 1 sun illumination. these values were compared with a liquid-based electrolyte. compared to such an analysis, the jsc obtained was comparatively lower, and the voc remained nearly the same. the photovoltaic performance is also recorded at 0.1 sun illumination. the performance, in this case, was 10%, and this value did not vary even for 10wt% of polymer. this indicates a constant and high-power yield using innovative technology. this is the highest value recorded for any solid-state dsscs at 0.1 sun illumination. the ipce results show a high conversion efficiency with a constant plateau at 75% in the range 19 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 of 400-600 nm showing the appropriate and suitable light-absorbing properties. the viscosity of the electrolyte greatly influences the diffusion of charge carriers in the device. the viscosity is studied by calculating the electrolyte's apparent diffusion coefficient (dapp). a small limiting current is produced at lower concentrations on varying the co(ii)/(iii) ratio. this indicated that the diffusion-determining species is solely the redox couple. on conducting a comparative analysis, the liquid electrolyte shows a higher dapp value when compared to the polymer electrolyte counterpart, reducing up to 50% when 10wt% polymer is added. thus, these results show that the diffusion rate significantly decreases when adding a certain amount of polymer to the electrolyte. the transient photocurrent measurements are studied and analyzed. at the low intensity of light, a steady photocurrent value is obtained, slightly delayed under the absence of pvdf-hfp. as the pvdf-hfp content increases, the current spike increases, and the photocurrent gradually decreases. this shows the reduced charge transportation in the polymer-based electrolyte giving rise to a reduced photocurrent. the charge transfer resistances at the tio2/electrolyte interfaces, electron lifetime and measured voc values are identical despite varying the polymer content. the chemical capacitance distributions show a similar state density and minor change in tio2 energy bands. the stability of the devices is studied with and without the 4wt% polymer content. the fabricated devices are placed under continuous 1 sun illumination. after nearly 700 h, the device with the polymer retained 90% of its initial pce, whereas the polymer-free device retained 90% of its initial pce after only 200 h, which further dropped by 75% after 500 h. the primary reason for a drop in jsc for photovoltaic performance can be attributed to the solvent's partial evaporation, which reduced surface contact area and increased viscosity. this study produced a device with a pce of 8.7%, which even increased to 10% under 0.1 sun illumination using a co-gel electrolyte. the device's charge carrier transport and interfacial characteristics can be further improved to get a superior value of pce and improve the diffusion of redox species. strategies to improve dssc performance the shockley-queisser limit of a dssc is 33.8% under am 1.5 g and 1000 w/m2 irradiation. the optimal bandgap through this limit is 1.3 ev which is reduced to 1.9 ev and a pce of 25%, which is the theoretical value. the jsc value at this condition is 17 ma/cm 2. the voc value is equal to eg/e. here the bandgap is determined by the ec level of tio2 and the redox potential of the electrolyte. this value obtained is always lesser than the bandgap of the dye. additives, chemical modification, and thin metal oxides can alter the set level. these added layers/modifications can improve the dssc performance by altering the charge transfer kinetics. it is important to note that even redox electrolytes play a crucial role in increasing the redox potential [12]. some electrolytes might aid recombination, which may correspondingly impact the fermi level. the best voc value obtained for a tio2-based dye is 1.4 v, for a co(bpy)3 is 0.9 v and for a device using spiro-ometad is 0.8 v. it is important to have a long electron lifetime to increase the voc of the device. the electron transport time should be lesser than the lifetime to get maximum output. the transport resistance decreases when a tio2/c(tio2) is charged. the rrec value should be as high as possible to increase current collection efficiency and output voltage. as the thickness of a particular layer increases, the rrec value decreases. rs values are 20 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 nearly impossible to eradicate. han et al. showed that it was possible to reduce the rs value to 1.8 ω/cm2 by modifying the catalytic performance of the counter electrode. the unavoidable resistances cannot be minimized. however, the use of pedot at the counter electrode has been shown to resist short-circuiting. the usage of co-based redox electrolytes along with porous mesoporous films is usually better for device performance. moreover, the addition of an anti-reflective layer on tio2 has been shown to improve light-harvesting efficiency. changing the mesoporous film by having reflective particles or voids is also possible. the tio2 used is known for being an excellent photocatalyst. however, the high bandgap of tio2 is unfavourable, and this can be altered by using a thin layer of al2o3 or mgo. recently, even sno2 has been a helpful candidate in dsscs, with only electron mobility being its only limitation, thus, having lower performances than tio2 [12]. a photosensitizer used in a dssc should have a robust structure with valuable properties to prevent charge recombination and encourage electron and hole transfer. apart from this, an efficient dye has a high excited lifetime and yield. as excited lifetime increases, the injection efficiency increases. wang et al. used an r6 dye on a mesoporous al2o3 film to generate enhanced device efficiencies. co-sensitization is also a viable approach to generating higher performance. a higher loading can also improve the output current of the dssc device. a perfect dye should have the following properties [13]: • absorbance near ir and visible region • strong anchoring group for binding to the photoanode surface • homo and lumo levels should be well aligned with the electrolyte and photoanode • fluorescent properties • hydrophobic • no aggregation • solid thermal, mechanical, chemical and electrochemical stability ru-based dyes’ strong photoelectrochemical properties have made it a staple material in dsscs and a first of its kind to record high efficiencies. alternatives like fe, pt, cu, rh and os-based dyes are being investigated. organic dyes are also another option because they are eco-friendly and have higher extinction coefficients. moreover, its tunable energy levels can improve the absorption regions of the device. studies have shown that steric hindrance decreases the dye loading on the photoanode surface, reducing the short circuit current value. crown ether substituted carbazole dye with tio2 photoanode and iodide/triiodide electrolyte produced an efficient device because the li-ions coordinated with the crown ether prevented the unnecessary migration of tio2. a photosensitizer with an oligothiophene-substituted unit produces an efficiency close to the traditional n719-based devices. on comparing the performance, the triphenylamine device produces the highest voc due to the blocking effect of phenyl groups. the coumarin device has the lowest voc, but the high absorption coefficient yields a higher jsc, compensating for the pce value. squaraine-triarylamine conjugate dyes with an additional number of anchor groups improve the device's efficiency. researchers concluded that having a multichromophoric structure with one chromophore having light-harvesting properties and possessing the acceptor molecule is a strategy to improve the device's efficiency. studying the optimum number of alkyl groups to positively impact the performance of a dssc is of utmost importance. it was studied that the optimal number is 3 to 4 21 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 thiophene units in hexyl substituted oligothiophenes. porphyrins and phthalocyanines are other groups of dyes that can be used in their individual or metal complex forms. the organic part of this dye improves the photoelectrochemical and light-harvesting properties of the device. phthalocyanines with different modifications were studied. in a particular modification, varying the phthalocyanine cycle parallel to the tio2 surface reduces recombination but produces a counter effect of reducing the device efficiency. bulky substituents could carry out the same effect but at moderate efficiency. a device with zn-porphyrin complex and a [co(bpy)3] 2+/3+ resulted in an efficiency of 7.8%. devices using porphyrins as a dye have attained efficiencies nearing ru-based devices. moreover, unlike ruthenium dyes, porphyrins can be tuned to vary the homo and lumo levels. moreover, further research can be done to reduce dye aggregation, improve absorption properties and enhance the long-term stability of the molecule. a porphyrin dye is a practical solution for a porphyrin gy50 dye with di(p-alkylphenyl) amine in the meso-position and a benzothiadiazophenyl spacer between the porphyrin cycle and carboxyl group [14]. an ideal electrolyte should possess the following properties [13]: • effective regeneration of the dye • fast diffusion of charge carriers, high conductivity and effective contact • long term thermal, chemical and thermochemical stability • not be corrosive • it should be transparent to absorption regions of the dye apart from the regular iodide/triiodide system of redox mediators, cobalt redox mediators have been highly recommended. the wide range of potentials, solubility in different solvents and their unique chemical structure gives these compounds an upper hand. water-based electrolytes have exhibited more excellent stability, which paves the way for eco-friendly devices. however, the slow electron transfer of co-based redox mediators is what restricts them from commercialization. using additives like triphenylamine (tpa) helps overcome such limitations, producing faster electron transfer and higher voc values. although cu-based redox mediators show faster recombination rates, the electron lifetimes are surprisingly long, which can be further developed to obtain favourable performances. the usage of a mixture of ethylene carbonate and acetonitrile and tetrapropylammonium iodide and iodine is a suitable dye for high efficiency, but it impacts the performance of tio2 negatively in the long run. redox pairs like br/br2, scn -/(scn)2, and co ii/coiii are being heavily researched, but their performance is not comparable to that of the i-/i3 pair. another approach to improve electrolytes is using additives. in this case, the most common additive is guanidine thiocyanate, which modulates the electrolyte band levels and reduces the recombination rate. liquid ionic electrolytes are also of notable importance. they are stable and have high conductivity and low vapour pressure at room temperature. however, the property of them being able to evaporate or leakage restricts their usage in practical implementation. creating gel and solid-based electrolytes is being considered as an alternative. lithium iodide and 3hydroxypropionitrile are solid electrolytes used in a dssc device. unfortunately, it possessed low conductivity and poor photoanode surface contact, which was resolved partially with sio2. polymer electrolytes are also being considered. for example, the polyethylene oxide and polydimethylsiloxane mixture were one such case, but they yielded low pce values. egg albumin was also studied as a possibility for gel electrolytes. the protein was initially functionalized to 22 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 improve cross-linking and conductivity. znal double-layered hydroxides were also used as additives, whereby a notable increase in voc values was observed [13]. the structure of the semiconductor used plays a crucial role in device performance. the use of tio2 nanofibres improves the efficiency to nearly double the value compared to tio2 nanoparticles. tio2 modified with graphene oxide, and nitrogen-reduced graphene oxide produced an efficiency of 7.19% with an optimal loading of 0.2 wt% of nitrogen-reduced graphene oxide. zno is also considered a suitable alternative because of its high electron mobility. however, when compared to tio2, zno has shallow stability. on loading a similar amount of zno and tio2 on a particular device, the tio2 counterpart showed nearly 4 times the value of the znobased device. other alternatives like sno2, nb2o5 and nio are being studied, but much research is pending to commercialize these materials. the carboxyl group is the most widely used anchoring group. however, techniques have been used that do not require an anchoring group [12]. hafnium, zirconium porphyrin, and phthalocyanines have been synthesized with a high affinity for polyoxometalates, forming a solid binding phenomenon, thus eliminating anchoring groups. similarly, carboxyl-based ligands with a nitrogen-containing heterocycle bind to the photoanode surface to form a metal complex. co-adsorbents are used to prevent recombination and dye aggregation on the photoanode surface. cholic acid derivatives are often used as co-adsorbents. a dssc using thiophene substituted bithiazole resulted in an efficiency of 1.13%. on incorporating it with cdca, the dye efficiency increased by 1.25%. a new co-adsorbent based on triazoloisoquinoline was synthesized. this was coupled with n719 dye to increase the efficiency from 8.36 to 8.83%. it is essential to understand that the optimal amount of co-adsorbent being used is also necessary. co-sensitizing various dyes together is a valuable strategy for improving the device's output current, voltage and electron lifetime. however, it is essential to note that the electron lifetime values from each dye are similar. a useful co-sensitizer for n719 is [cd3(iba)3(cl)2(hcoo)(h2o)]n and {[cd1.5(iba)3(h2o)6]∙3.5h2o}n. a co-sensitized device with zn-phthalocyanine complex and triarylamine-bithiophene dye was formed to increase the device's efficiency with a value greater than its counterparts [13]. in the case of solid-state dsscs (ssdsscs), the usage of a definite htm is the only differentiating factor. materials like pedot:pss and spiro-ometad are the common ones used. however, the compatibility of these materials with a mesoporous film. the faster recombination rates of ssdsscs are also a significant issue that needs to be solved, further limiting the output voltage values. a study was conducted where a dried ssdssc using a cu-redox electrolyte performed exceptionally well, regarded as a zombie solar cell. pyrrolidinium ionic crystals have been regarded for forming a 3-dimensional matrix responsible for the device's high efficiency and stability. high-performance dsscs are of profound interest because of their unique photovoltaic properties, which can be harnessed for multiple applications. however, several issues need to be solved and addressed to top a traditional solar cell. the practical usage of the dsscs comes to enhancing the device's performance in large areas. in actual conditions, as the area of the device increases, the efficiency decreases. the long-term stability of the device needs to be looked into, thus calling the need for scaling-up and optimization [12, 13]. 23 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 commercialization of dsscs ricoh is an electronics and technology-based company that aims at developing products and services to build more innovative solutions. ricoh has developed a fabrication procedure capable of producing a standardized and regulated quality of ssdsscs to ensure maximum efficiency. today, ricoh’s 300 mm ssdssc panel is one of the most used mass-produced samples. ricoh believes that dsscs being a high efficiency and high open-circuit voltage device, can undoubtedly be used to charge secondary cells. the usage of dsscs can be expanded to leds and switches where even under low illumination, the photovoltaic activity is not limited [15]. exeger is a swedish-based electronics company that works on products incorporating sustainable energy technologies. they have a patented technology that permits them to use dssc commercially. their innovation is termed powerfoyle, which has been actively used in their products. for example, the exeger headphones are coated with a dssc where the device with 1 hour of illumination enables 3 hours of playtime which also works during a cloudy day to allow 2 hours of playtime [16]. g24 innovations created the first commercial application. here the devices produced were thin, flexible and used in the case of portable electronics. the dsscs are used for purposes like camping and powering led systems. it uses a roll-to-roll manufacturing process. this allows the dssc to appear in a metal foil, reducing labour efforts. g24i believes that its innovation can solve the problems experienced by batteries, and the incorporation of dsscs in bags, and tents, can be used to charge electronic devices like mobile phones, cameras and portable systems. g24i have even large-scale purposes of dsscs where their innovation has been used in advertising for both outdoor and indoor applications. they are currently working on adding this innovation to laptops, mobile phones, gps systems, and av devices to extend their lifetime and develop more commercial designs for their products [17]. the usa has been a pioneer in dssc applications, where it has pioneered several innovations in various departments. the rising concern of depleting non-renewable sources of energy was realized rather quickly by the usa, where they shifted to renewable sources quickly, with dsscs being a valid contender in this case. the application of dsscs in the us market is segregated into a few categories: outdoor advertising, charging, embedded electronics and automobiles. as of 2019, 33.3% of dssc applications were used in portable charging because of their high power output and fast recharging rates. building-integrated photovoltaics is a field that dsscs have captured massively (13%) as it is forecasted to power residential areas and domestic requirements. dsscs are in line to revolutionize grid technology as it aims at decentralizing power requirements with dye-powered applications paving the way in the coming years. automobile integrated photovoltaics is a massive market that dsscs can capture, especially in regions like north america and europe, to propel the automotive market further. some notable companies in dssc applications are 3g solar, sharp and fujikura [18]. 24 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 figure 2. dsscs market categories 3g solar manufactures several dssc-based products such as sports monitors, building sensors, portable medical devices, surveillance cameras and wireless products. the principle behind their commercial activities is very straightforward optimizing existing dssc technologies. they have merged aesthetics with functionality to create all its products with high power, low cost, coloured devices, high transparency and flexible characteristics. moreover, unlike other solar technologies, 3g solar’s products provide a nearly constant efficiency [19]. sharp has also developed a similar solution where it made the world’s highest level of power generation for indoor applications with iot principles. it provides an lcd with re embedded controllers' continuous and constant operation with environment indoor lights. this can be used for indoor applications, iot, and industrial equipment [20]. fujikura’s dssc products are personalized as per the consumer’s requirements. they have 2 variants: indoor credit card-sized, 4 cell modules, and outdoor passport-sized, 8 cell modules. the indoor and outdoor products can produce 1.5 v and 3.0 v, operating between -30 to 50 oc with a light intensity of up to 100,000 lux, respectively [21]. research on fruits, vegetables and flowers flowers desalegn and coworkers conducted a study using natural dyes obtained from flowers, namely, amaranthus caudatus (ac), bougainvillea spectabilis (bs), delonix regia (dr), nerium oleander (no) and spathodea campanulata (sc) [22]. the flowers were initially collected in sufficient amounts. they were allowed to dry for 30 days after collection and then crushed into powder. the powders were then dissolved in different solvents like ethanol and hcl to extract the dyes. ac and bs were dissolved in hcl and ethanol and mixed to create a hybrid dye. the dyes were then stored and covered with aluminium foils to prevent light degradation. the slurry obtained was then filtered to obtain a clear dye solution. the photoanode used in this case is tio2. the ito sheets used were made conductive using pedot:pss, and a polymer gel electrolyte is used based on a pvp polymer. 25 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 the absorption characteristics of the dyes are studied. ac and bs extracted on ethanol produced absorption maxima peaks at 665 nm and 413 nm. the main component of these dyes is chlorophyll. the hcl version of these dyes produced maxima of 500-600 nm for ac and 400-600 nm for bs. the mixed version of these dyes produced maxima at 670 and 536 nm for ac and 668, 536, 479, 446 and 416 nm for bs. for dr, there is an absorption peak at 516 nm, which corresponds to the anthocyanin’s component in this dye. no and sc in hcl did not have any notable absorption peaks in the visible region. this can be attributed to the fact that anthocyanin was the component extracted vigorously in hcl, which does not absorb light in the visible region. on acidifying this, it appeared to have a colour. this can be concluded that anthocyanin exists in an equilibrium relationship between quinoidal and flavyium cation. the photovoltaic performance of these dyes is recorded. the ff are above 50%, voc varies from 0.45 to 0.55 v, jsc varies from 0.013 to 1.82 ma/cm 2. a voc value of 0.55 v and jsc value of 1.82 ma/cm2 were obtained for ethanol-extracted ac, with a pce of 0.61%. this efficiency value obtained is one of the highest recorded for natural dyes and comparable to other studies conducted. the relatively high performance can be related to the broad absorption characteristics of the dye on tio2. moreover, ac has the shortest skeleton distance between the dye and tio2 surface, which helps in electron injection. bs has a much lower performance than ac when extracted by ethanol. this can be related to bs's higher chlorophyll concentration, leading to dye aggregation (concentration quenching). the performance of ac and bs extracted by hcl were also studied. the ac and bs efficiencies were 0.61% and 0.033% in ethanol and 0.325% and 0.018% in hcl, respectively. the efficiency for the mixed dye (0.114% for ac and 0.164% for bs) was lower than the sum of their counterparts. this indicates that ac and bs do not have complementary or synergistic effects that could contribute to optimizing the device. the reasons for such an occurrence are a) ac and bs absorb light from a similar region which can lead to optical losses or reduced exciton generation, and b) solid steric hindrance amongst the ac and bs dyes restricts uniform and regular packing on the tio2 surface, leading to limited electron transfer. the dyes extracted by ethanol had higher performances than their hcl counterparts. this is because anthocyanins extracted are much more soluble in ethanol than in hcl. its higher solubility in ethanol reduces dye aggregation, which eventually contributes to higher efficiency. dr extracted using hcl showed a pce of 0.03%, sc with 0.003% and nr with 0.013%. in the case of dr, although the main component was anthocyanin, there were no carboxyl or hydroxyl groups present which could behave like anchoring groups to bind to tio2. the ipce measurements show that ac had a maximum efficiency value of 52% at 430 nm with ethanol and 43.5% at 320 nm with hcl. bs shows a maximum efficiency of 27.7% at 410 nm with ethanol. the mixed dye and hcl peaks occur with 5.8% at 345 nm and 16.7% at 330 nm for bs dyes, respectively. dr shows a maximum efficiency of 5.1% at 340 nm. no shows a maximum efficiency of 4.7% at 330 nm. a significant blue shift was observed for ac, bs and dr dyes due to the interactions between the dye and tio2. natural dyes like this should be considered even in the future because of the enormous scope for development, eco-friendly, low-cost and energy-efficient mechanisms. 26 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 fruits and vegetables m c ung and coworkers conducted a study where they fabricated dsscs using dyes obtained from fruits like black olive, mangosteen and wild mangosteen. along with this, the dye obtained from blueberry is used as a standard reference. the study aims to understand the photovoltaic performance of anthocyanin dyes and the performance variation with a light source and counter electrode [23]. the dye sources were initially cut into small pieces, crushed, and washed with distilled water to obtain dye solutions. the samples were then crushed and mixed with distilled water to obtain a coloured dye solution. the solid residues were separated, and the remaining solution was used as the sensitizer. even n719 dye was fabricated and used as a standard measure. all the dyes show a broad spectral range from the uv-vis absorption spectra, especially in the visible region. thus, confirming that all the dyes are capable of becoming dssc sensitizers. however, the absorption range and characteristics of each dye were very different. this can be related to the fact that different type and concentration of anthocyanin is present in the dye solution. it was observed that black olive showed the broadest and most broad absorption spectra. all the dyes have light-harvesting and electron injection properties, making them slightly suitable for further device performance. thus, making it possible to study the photocurrent and photovoltage measurements. however, studying all the dyes shows that black olive shows the highest efficiency because of its higher intensity and broad absorption properties. this also results in higher ff. the device measurements are as follows: voc = 0.543 v, jsc = 0.11 ma/cm 2, ff = 0.54, pce = 0.08%. the broad spectrum of sunlight enabled dsscs to function efficiently. however, if this light source is varied to metal halide lamps that have a narrower spectrum, the performance of the dssc correspondingly decreases. this can be related to the fact that, at broader spectral regions, more excitons or electron-hole pairs are generated, therefore, producing more current. this can be seen through the performance of black olive under a metal halide lamp, having 0.08% pce but under sunlight, having a pce of 0.13%. a carbon-based counter electrode provides the dssc with extra surface area with a porous morphology to facilitate electron transfer to the load and result in a higher available pce. carbon paste as a ce provided a higher pce, ff, jsc and voc value than carbon soot. this can be attributed to better contact between carbon paste and fto, which is much more robust, with faster electron transfer. this study shows that dsscs using black olive can be considered a viable anthocyanin-based device. however, black olive can enhance performance with different light sources, counter electrodes, and materials; higher efficiencies can be worked. conclusions dsscs are one of the most promising and innovative photovoltaic devices out there that has the potential to become highly commercial. the examples reviewed in this article highlight how easy tuning and molecular engineering can produce impactful dsscs. each component of a dssc plays a significant role in the device's performance and stability. it’s very characteristic of low 27 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 processing costs, abundant material sources, and easy fabrication process create a substantial advantage for this innovation to stand in the market. comprehending the potential of dsscs, the various materials that can be used, strategies to adopt for high-efficiency dsscs, advantages and disadvantages, commercial activities, research undergoing in india and the novel fruits and flowers that are being studied are the topics covered in this review. the constant effort to revamp and re-modulate the escalating of dssc performance is of great interest. moreover, researchers need to focus on how this commercial technology can be further scaled up through low-cost, zero toxicity and energy-efficient mechanisms that can benefit society. lastly, the need to identify additional robust materials that overcome the limitations of existing components is of utmost importance, which can be tackled through extensive research and studies. this study aims to understand the different and viable commercial materials that researchers can exploit to make dsscs reach the market as soon as possible effectively. along with the active components and a brief introduction of dsscs, the review highlights a few examples of certain high-efficiency dsscs using variations in different components like the photoanode, photosensitizer, and electrodes. along with growing electricity and power demands, it is essential to understand how we power some of our daily appliances through a renewable source of energy (figure 3). this review also points out the commercial activities companies have incorporated using dsscs. along with not being extremely stable and efficient, the article elaborates on the various strategies researchers can adopt to improve device performance and stability. dsscs being a recent and novel innovation, india has been actively researching this particular domain. here, we can see the various components of a dssc that are being researched by different labs in india and how each research group aims to optimize the device's capabilities. since the majority of the photovoltaic technologies are shifting to more organic and sustainable modes, the current sources of flowers and fruits have also been elucidated with a few vital examples and much room for improvement. it is important to note that, once these obstacles have been overcome, the road to the commercialization of dsscs is straightforward and it is only a matter of time that this evolution of dsscs becomes a reality. figure 3. dsscs improvement over years 28 computational and experimental research in materials and renewable energy (cerimre) volume 5, issue 1, page 1-29 eissn : 2747-173x submitted: may 24, 2022 accepted: may 28, 2022 online: may 31, 2022 doi: 10.19184/cerimre.v5i1.31475 acknowledgements i want to thank dr. s v eswaran, ex: head (chem.) and dean (acad.), st. stephen's college, delhi; adjunct prof. 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