فهرست مطالب masuod bayat

Machining of hard workpieces is one of the most important challenges of the manufacturing industry. Hence, new methods were added to traditional machining. Ultrasonic vibration machining is one of these methods. The advantages of using ultrasonic vibrations compared to traditional machining include reducing machining forces, reducing tool wear and friction, increasing tool life, creating intermittent cutting conditions, increasing surface quality, and so on. To vibrate the tool, a horn with a resonant frequency of 20,633 Hz was analyzed by Abacus software. In this study, the effects of cutting speed, feed rate, conventional machining conditions, and vibration machining conditions at three different hardness of 15, 30, and 45 Rockwell C for the workpiece on surface roughness and tool wear were evaluated. The experiments were designed at full factorial, and a total of 54 experiments were performed. The results showed that at higher workpiece hardness by applying vibration the surface roughness was reduced. The surface roughness (Ra) in machining by means of ultrasonic vibrations is up to about 36% less than conventional machining in various machining parameters. In addition, the temperature in vibration machining is lower about 15% at higher stiffness of the workpiece. Also, with the increase in the hardness of the workpiece, the tool wear was increased, which is less by applying ultrasonic vibrations. Also, by applying vibrations, tool wear was reduced in total, which can be minimized by selecting cermet tools and applying vibrations in 4140 AISI steel machining.

Although Sheikh E Eshraq is not a political philosopher in common sense, he has attracted the attention of many researches in the field of political thoughts thanks to his serious efforts to describe and clarify savant position on apex of religious and mundane pyramid presidency, as well as his tragic excommunication and murder, which strengths fault of his political activity. Sheikh E Eshraq was affected by “Fahlavion`s arbitrator thoughts”, “Persian philosophers” and “Platonic Eshraqi wisdom”, and he believed that sovereignty and presidency shall be devoted to one who is deifier and who is skilled in wisdom, owns greatness, dignity and is able to conduct weird habit (walking on water, Alienating the spirit from the body, visiting angels, etc) he denied owning. He denies divine savant to get presidency and sovereignty by force, dominance and violence and he introduces his residency era as divine and luminous one.