نتایج جستجو برای: Volume fraction
تعداد نتایج: 447302 فیلتر نتایج به سال:
in this article cuo/water nanofluid was synthesized by using polyvinylpyrolidone (pvp) as the dispersant. thenanofluid stability period and the heat transfer enhancement were determinedby measuring the thermal conductivities. to study the nano-fluid stability, zeta (ζ) potential, and absorbency were measured under different ph values and pvp surfactant concentrations; also thermal conductivity...
this work presents a model for calculating the effective thermal conductivity of nanofluids. the proposed model includes the effects of nanoparticles and thermal conductivity base fluid.we will focus on experimental of the volume concentration parameter and temperature on thermal conductivity, nano-fluid combination and multi-walled carbon nanotubes-oxide / copper-paid deionized water. th...
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the main purpose of this study is to perform numerical simulation of nanofluids as the coolant in vver-440 fuel rod bundle. the fuel rod bundle contains 60 fuel rods with length of 960 mm and 4 spacer grids. in vver-440 fuel rod bundle the coolant fluid (water) is in high pressure and temperature condition. in the present thermo-hydraulic simulation, water-al2o3 nanofluids containing various vo...
introduction: we investigated the difference in left ventricular ejection fraction (lvef) and end-systolic volume(esv) measured by gated myocardial perfusion spect (gspect) in the post-dipyridamole stress and rest periods, and compared the results with the perfusion patterns found in the conventional non-gated tomograms. methods: 297 consecutive patients were studied with post-stress and rest 9...
in this paper, turbulent mixed convective heat transfer of water and al2o3 nanofluid has been numerically studied in a horizontal tube under non-uniform heat flux on the upper wall and insulation in the lower wall using mixture model. for the discretization of governing equations, the second-order upstream difference scheme and finite volume method were used. the coupling of pressure and veloci...
Based on molecular dynamics simulation results, a model was developed for determining elastic properties of aluminum nanocomposites reinforced with silicon carbide particles. Also, two models for prediction of density and price of nanocomposites were suggested. Then, optimal volume fraction of reinforcement was obtained by genetic algorithm method for the least density and price, and the highes...
The conventional liquids have some limitations regarding the thermal properties. The nanoparticles addition is one of the techniques which can modify them. In this research, heat transfer coefficient (h) and pressure loss (Δp) of various nanofluids containing Al2O3, SiO2 and MgO nanoparticles dispersed in water in an annular tube with constant wall temperature were numerically considered. Accor...
one of the models that can be used to study the relationship between boolean random sets and explanatory variables is growth regression model which is defined by generalization of boolean model and permitting its grains distribution to be dependent on the values of explanatory variables. this model can be used in the study of behavior of boolean random sets when their coverage regions variation...
In vivo measurement of cerebral arterial and venous volume fractions is important to the understanding of brain physiology and function. By using an intravascular perfluorocarbon and 19F NMR at 4.7 T, regional arterial and venous volume fractions from an intact rat brain were resolved based on the pseudodiffusion coefficients, which were (33 +/- 7) x 10(-3) and (0.45 +/- 0.13) x 10(-3) mm(2)/se...
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