888 research outputs found

    Thermosolutal Marangoni boundary layer magnetohydrodynamic flow with the Soret and Dufour effects past a vertical flat plate

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    AbstractA numerical study of laminar magnetohydrodynamic thermosolutal Marangoni convection along a vertical surface in the presence of the Soret and Dufour effects has been performed. The diffusion-thermo implies that the heat transfer is induced by concentration gradient, and thermo-diffusion implies that the mass diffusion is induced by thermal gradient. In conformity to actuality, it is assumed that the surface tension varies linearly with both the temperature and concentration and that both interface temperature and concentration are quadratic functions of the interface arc length x. The general governing partial differential equations are converted into nonlinear ordinary differential equations using unique similarity transformations. The aim of this study is to investigate the effects of Hartmann number (0 ≤ M ≤ 5), thermosolutal surface tension ratio (0 ≤ R ≤ 5), Soret parameter (0.1 ≤ Sr ≤ 2), Dufour parameter (0.03 ≤ Du ≤ 0.6), Prandtl number (0.72 ≤ Pr ≤ 10) and Schmidt number (0.3 ≤ Sc ≤ 3) on the fluid velocity heat and mass transfer. It is found that, both of temperature and concentration gradient at the wall increases as the thermosolutal surface tension ratio increases. Also, the increase in Prandtl number results in an enhancement in the heat transfer at the wall

    Changes in lipid oxidation of reconstituted omega-3 plus milk powder treated by superheated steam

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    In this study the effect of superheated steam on the oxidative stability of reconstituted omega-3plus milk powder was studied. The changes in fatty acids, peroxide, acids, thiobarbutric acid reactive substances (TBARS), and p-anisidine values were measured to reconstitute omega-3 plus milk powder in relation to thermal treatment by using a superheated steam (SHS) with different temperatures and time periods. The temperature and time period ranged from 120-180 °C between 5-15 min. For applying the SHS treatment did not produce changes in SFA, MUFA and PUFA at 120-150 °C to 10-15 min as compared with the control. While, the proportion of PUFA and MUFA values were recorded differences on temperature 180 °C comparison with control. The result of POV showed no changes between the temperature 120-150 °C compared with control, but indicated significant differences at the temperature 180 °C with long time 15 min. Acids and p- anisdine values did not show any differences between temperature 120-180 °C for a short period of time 5 min compare with the control, but recorded significantly on long period of time 10-15 min compared with the control. The values of TBARS showed no significant differences in temperature 120-150 for 5 min compare with control. This study showed oxidative stability of milk fat supplied long chain unsaturated fatty acids treated by SHS on temperature range 120-150 at time 5-10 min with some affected by the high temperature 180 °C at 15 min can maintain the quality of fatty acid and milk fat

    The Impact of Some Economic Factors on Imports in Jordan

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    The purpose of this paper is to build a multiple linear econometrics model which reveals impact of some important economic factors on Jordanian imports. Different models have been modified to get the best model in estimating and predicting imports. The major findings of the paper were that imports in Jordan are dominated by Consumer Price Index (CPI), Remittance (REM), Relative Prices RP) and Exchange Rate(ER) respectively. ER has a small coefficient compared to other predictors. CPI actually contributes more to the model because it has a larger standardized coefficient.

    Entropy generation for MHD natural convection in enclosure with a micropolar fluid saturated porous medium with Al2O3Cu water hybrid nanofluid

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    This contribution gives a numerical investigation of buoyancy-driven flow of natural convection heat transfer and entropy generation of non-Newtonian hybrid nanofluid (Al2O3-Cu) within an enclosure square porous cavity. Hybrid nanofluids represent a novel type of enhanced active fluids. During the current theoretical investigation, an actual available empirical data for both thermal conductivity and dynamic viscosity of hybrid nanofluids are applied directly. Numerical simulation have been implemented for solid nanoparticles, the volumetric concentration of which varies from 0.0% (i.e., pure fluid) to 0.1% of hybrid nanofluids. Heat and sink sources are situated on a part of the left and right sides of the cavity with length B, while the upper and bottom horizontal sides are kept adiabatic. The stated partial differential equations describing the flow are mutated to a dimensionless formulas, then solved numerically via the help of an implicit finite difference approach. The acquired computations are given in terms of streamlines, isotherms, isomicrorotations, isoconcentraions, local Began number, total entropy, local and mean Nusselt numbers. The data illustrates that variations of ratio of the average Nusselt number to the average Nusselt of pure fluid Num+ is a decreasing function of Ha and φ, while e+ is an increasing function of Ha and φ parameters of hybrid nanofluid

    Cattaneo–Christov heat flux impacts on MHD radiative natural convection of Al2O3-Cu-H2O hybrid nanofluid in wavy porous containers using LTNE

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    This paper aims to examine impacts of Cattaneo–Christov heat flux on the magnetohydrodynamic convective transport within irregular containers in the presence of the thermal radiation. Both of the magnetic field and flow domain are slant with the inclination angles Î© and γ, respectively. The worked fluid is consisting of water (H2O) and Al2O3-Cu hybrid nanoparticles. The enclosures are filled with a porous medium, and the local thermal nonequilibrium (LTNE) model between the hybrid nanofluids and the porous elements are considered. Influences of various types of the obstacles are examined, namely, horizontal cold elliptic, vertical elliptic and cross section ellipsis. The solution methodology is depending on the finite volume method with nonorthogonal grids. The major outcomes revealed that the location (0.75, 0.5) is better for the rate of the flow and temperature gradients. The higher values of H* causes that the solid phase temperature has a similar behavior of the fluid phase temperature indicating to the thermal equilibrium state. Also, the fluid-phase average Nusselt number is maximizing by increasing Cattaneo–Christov heat flux factor

    Three-dimensional boundary layer flow of nanofluids due to an unsteady stretching surface

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    A numerical solution has been obtained for the unsteady three-dimensional stretching flow and heat transfer due to uncertainties of thermal conductivity and dynamic viscosity of nanofluids. The term of nanofluid refers to a solid–liquid mixture with a continuous phase which is a nanometer sized nanoparticle dispersed in conventional base fluids. The unsteadiness in the flow and temperature fields is caused by the time-dependent of the stretching velocity and the surface temperature.  Different water-based nanofluids containing Cu, Ag, and TiO2 are taken into consideration. The governing partial differential equations with the auxiliary conditions are converted to ordinary differential equations with the appropriate corresponding conditions via scaling transformations. Comparison with known results for steady state flow is presented and it found to be in excellent agreement

    Length Biased Burr- XII Distribution: Properties and Application

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    Burr XII distribution is widely applicable in reliability and life testing problems in engineering as well as in survival analysis. The concept of weighted and size- biased sampling and length biased  distribution due to importance of this kind of distributions and it's application  in many fields such as medicine, ecology, reliability and human populations. In this paper, length biased Burr XII  distribution is proposed and studied. Different properties of this new distribution are discussed such as the density function and its behaviour , moments, hazard , survival functions and order statistics. The parameters of this new distribution are estimated by maximum likelihood method . The observed information matrix is derived. Finally, we provide a simulation and real data analysis to see how the new model is applicable in practice

    Maximum Likelihood Estimation for Length biased Burr- XII Distribution with Censored Sample

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    In this paper, defined by [1],the maximum likelihood estimation for the parameters of the LBB-XII distribution are studied.Also, different types of censoring, such as, type I, type II. A simulation study is perform to evaluate the maximum likelihood estimates

    Sumudu decomposition method for Solving fractional-order Logistic differential equation

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    In This paper, we propose a numerical algorithm for solving nonlinear fractional-order Logistic differential equation (FLDE) by using Sumudu decomposition method (SDM). This method is a combination of the Sumudu transform method and decomposition method. We have apply the concepts of fractional calculus to the well known population growth modle inchaotic dynamic. The fractional derivative is described in the Caputosense. The numerical results shows that the approach is easy to implement and accurate when applied to various fractional differentional equations. &nbsp
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