surface roughness is one of the most important parameters that plays very critical role in determining the quality of engineering components. a good surface quality resulting in improve of fatigue strength, corrosion and wear resistance of the workpiece. on the other hand, increasing cutting speed and decreasing time of machining are desirable for manufacturers in order to reduce costs and incr...

background: along with the rapid growth of technology its related tools such as computer, monitors and video display terminals (vdts) grow as well. based on the studies, the most common complaint reported is of the vdt users. methods: this study attempts to design a proper tool to assess the visual fatigue of the vdt users. first draft of the questionnaire was prepared after a thorough study on...

background & aim : increasing students’ academic stress especially during taking final exams may result in sleep  disorders, fatigue, poor academic performance and low functional efficiency. the aim of this study was to determine the relationship between sleep quality with fatigue severity and academic performance of nursing students. methods & materials : in a cross-sectional study, the sleep ...

The recently developed nanobainitic steels show high strength as well as high ductility. Although this combination seems to be promising for fatigue design, fatigue properties of nanostructured bainitic steels are often surprisingly low. To improve the fatigue behavior, an understanding of the correlation between the nanobainitic microstructure and the fatigue limit is fundamental. Therefore, o...

a new output structure for class e power amplifier (pa) is proposed in this paper. a series lc resonator circuit, tuned near the second harmonic of the operating frequency is added to the output circuit. this resonator causes low impedance at the second harmonic. the output circuit is designed to shape the switch voltage of the class e amplifier and lower the voltage stress of the transistor. t...