this paper presents the effects of geometric tolerances on the rotating shafts natural frequencies. due to modeling the tolerances, a code is written in matlab 2013 software that produces deviated points. deviated points are controlled by different geometric tolerances, including cylindricity, total run-out and coaxiality tolerances. final surfaces and models passing through the points are crea...

in this study, friction stir spot welding (fssw) is applied to join the tial6v4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. in this regard, the speed of the tool rotation was considered as 800, 1000, and 1200 rpm, as well as the tool dwell time was set at 7 and 12s. microstructural ...

in this research, the compositing of the surface of az31b magnesium alloy with cnt was studied by fsp. the parameters under study were rotational speed (500-1500 rpm), transverse speed (12-44 mm/min), number of passes (1-4), and cnt weight fraction (0-2%). microhardness testing, optical metallography, fesem, and eds analysis were employed for the characterization of the samples. the suitable li...

introduction recently, employment of rotary tillers has been expanded in gardens and small farms, especially in the northern of iran. however using the l-shaped blades in the conventional rotary tillers have some problems such as severe vibration problems, weeds stucking around the blades, forming the plow pan and lower performance due to the less powers of such small rototillers. therefore in ...

due to climate changes in recent years, in order to attain comfort and convenience, demands for heating, ventilating, and air conditioning (hvac) systems have been increased around the world, which has led to increases in emissions and power. desiccant cooling systems (dcss) are designed and built to reduce moisture and power consumption, create comfortable conditions for people in a building, ...

paddy de-awning using a de-awner increases the uniformity and flow rate of paddy grains through the orifices of hoppers, bucket elevators and chutes. in this study the effects of paddy variety, rotational blade speed and moisture content on performance of a prototype de-awner machine were investigated. the experiment was conducted in a factorial design with three factors, variety (hashemi and b...

Abstract The first step of implanting teeth is to drill a hole in the jaw bone. Excessive temperature produced during drilling is one of the destructive factors for bony tissue. If the temperature generation during surgical drilling exceeds the critical temperature, it could lead to osteonecrosis. This research intends to study drilling parameters such as drilling speed, feed rate, cooling con...

The basic aim of present study is to examine the effect of main friction stir welding (FSW) parameters on the quality of AA 6063 plate welds. Welding of AA6063 was carried out by a vertical milling machine, using different tools with a stationary shoulder and during the welding no external heating system was used. Different welding parameters studied were the tool rotational speed which varied ...

in this work, improved heat generation models are developed for straight and tapered shoulder geometries with different tool pin profiles in friction stir welding. the models are developed considering the welding process as a combination of the pure sliding and the pure sticking conditions. from the results, the amount of heat generation is directly proportional to the number of edges in the pi...