id	keyword
alkej-218	� �
alkej-218	ا �
alkej-218	vibration
alkej-218	fig
alkej-218	rop
alkej-218	drilling
alkej-218	penetration
alkej-218	depth
alkej-218	acceleration
alkej-218	rpm
alkej-218	soil
alkej-218	load
alkej-218	bit
alkej-218	wob