the effect of γ-al2o3 nanoparticles on heat transfer rate, baffle spacing and pressure drop in the shell side of small shell and tube heat exchangers was investigated numerically under turbulent regime. γ-al2o3-water nanofluids and pure water were used in the shell side and the tube side of heat exchangers, respectively. since the properties of γ-al2o3-water nanofluids were variable, they were ...

Semi-analytical solutions for vibration analysis of nonlocal piezoelectric Kirchhoff plates resting on viscoelastic foundation with arbitrary boundary conditions are derived by developing Galerkin strip distributed transfer function method. Based on the nonlocal elasticity theory for piezoelectric materials and Hamilton's principle, the governing equations of motion and boundary conditions are ...

Defocusing effects in modulation transfer function (MTF) measurement of charge coupled device (CCD) cameras is the main focus of current paper. We introduce measuring Point-spread function (PSF) in order to calculate the MTF and further more we will study the shape of MTF and its cut-off frequency by adjusting the lens focusing in different locations. A collimated white light LED by broadband s...

An autonomous underwater vehicle (AUV) with less noise and vortices as well as efficient power consumption, is pursued in this research by inspiration of shark swimming. Design, hydrodynamic analysis, modeling, fabrication, navigation, and control of this novel AUV is the main goal of this research. Detailed explanation of the test and experiment with a brief overview on fabrication are provide...

natural convective heat transfer of nano-fluid in porous media is present in many advanced engineering applications. in this work, this problem has been computationally simulated, using lbm. the configuration used includes a cold exterior region and hot interior cylinders with one-, two-, or three-cylinder arrangements. however, the effective area for heat transfer has been kept the same for al...

Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105  to 5 x 106...

in this paper, wavelet collocation method has been used to solve nonlinear fin problem with temperature dependent thermal conductivity and heat transfer coefficient. thermal conductivity of fin materials varies any type so that we consider thermal conductivity as the general function of temperature.  here we consider three particular cases, where we assume that thermal conductivity is constant,...

In this paper we propose a new method for ranking Z- numbers and generalizations. This method is based on the internal structure of the artificial neural network, which suggests that the structure of this network consists of inputs weights and the transfer function linear, nonlinear and sometimes linear and nonlinear. It is shown that the proposed method while possessing the ranking properties ...

Although turbulence is usually considered to be the primary cause of image blur, simultaneous and independent measurements of overall atmospheric modulation transfer function (MTF) and turbulence MTF over fairly long horizontal paths at 15-m average elevation indicate that, even at midday, aerosol MTF deriving from forward scatter is usually more dominant than turbulence MTF. Three different ex...