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In this paper, a comparison between a common and a novel prototype of freeze dryer has been considered. A freeze dryer does the action of drying based on freezing the product fluid in low pressure along with a sudden phase change. Using correct assumptions, the freezing heat, freezing time, drying time, and vacuum creating time have been calculated. The freeze dryer was designed in CATIA software based on a new P-T diagram cycle. The novel design is able to work as hot-air dryer and also vacuum dryer, as well as freeze dryer in vacuum. No need to extra refrigerator and the use of separate cycle for drying are two advantages of the novel design. A comparison between the capabilities of the classical and the novel designs suggests that the use of novel design as a domestic device would satisfy the users.

In this article, the gear ratio of RD (An Iranian made car by Iran Khodro Co.) vehicle gearbox with considering fuel economy and gearbox specifications is evaluated. In the first step, the gearbox advantages and its effects on the engine rotational velocity with considering road load and engine torque are investigated. It is distinguished that in a specified velocity of vehicle, engine speed in overdrive state is very lower than engine speed in fourth gear. It means that noise and fuel consumption and engine wearing and damages will be decreased. The optimized region of engine operation is identified. Using a geometric progression between automotive gear ratios and entering number of effective parameters such as specific fuel consumption, minimum mean effective velocity, and etc., overdrive gear ratio is computed. Finally the overdrive gear ratio is chosen 0.81 for vehicle.

In this paper, analytical and numerical analyses of radial and tangential velocities and pressure of lubricant film have been considered in an eccentric journal bearing. A 2D flow of shear-thinning viscous fluid is followed by Carreau-Yasuda mathematical model between two eccentric cylinders. The model is mathematically conserved from eccentric coordinate to concentric coordinate due largely to easy solution. Therefore, the PDE equations were converted to the ODE equations with a set of nonlinear algebraic first order equations with their boundary conditions. These kinds of equations are called boundary value problems (BVP) that can be solved with shooting method. The results are compared with 2D numerical simulation in the Fluent software. Lubricant tangential velocity and pressure distributions are examined in the dynamic journal bearing. The comparison of the results revealed that numerical analysis as same as analytical approach is a reliable method for determining lubricant motion in the gap.