Steady conjugate natural convection heat transfers in a two-dimensional enclosure filled with fluid saturated porous medium is studied numerically. The two vertical boundaries of the enclosure are kept isothermally at same temperature, the horizontal upper wall is adiabatic, and the horizontal lower wall is partially heated. The Darcy extended Brinkman Forcheimer model is used as the momentum equation and Ansys Fluent software is utilized to solve the governing equations. Rayleigh number (1.38 ≤ Ra ≤ 2.32), Darcy number (3.9 * 10-8), the ratio of conjugate wall thickness to its height (0.025 ≤ W ≤ 0.1), heater length to the bottom wall ratio (1/4 ≤ ≤ 3/4) and inclination angle (0°, 30° and 60°) are the main considered parameters. The presented results show the effect of these parameters on the heat transfer and fluid flow characteristics. These results include streamlines, isotherm patterns, and local and average Nusselt number for different values of the governing parameters. It is found that either increasing the Rayleigh number and the ratio of conjugate wall thickness to its height (d/H) or decreasing the ratio of heat source width to bottom wall (l/L), the average Nusselt number is increased. Also, it was observed that the average Nusselt number does not change substantially with inclination angle.
A new complex of Cr(UI) has been prepared. The kinetics and eqailibrium study of the substitution reaction for the complex Trans KfCr(ox)z(H 0)2].3l--h0 {T I }, with 4-aminoantipyrine {AAP}, bave been per£Qrm d in aqueous media at .(pH. = 4.9, 5.6 and 6.0) (!!?0.4M NaN03). Activation pararrieters for the reac(ions are {Eat= l.89l kCal
mor 1 , l:t=89.29 kCal mo1"1  
... Show MoreIn this study, the aqueous extract of (Typha domingensis Pers.) pollen grain (qurraid) to know its ability to manufacture silver nanoparticles. Qurraid is a semi-solid yellow food substance, sold in Basra markets and eaten by the local population. It is made from the pollen of the T. domingensis Pers. plant after being pressed and treated with water vapor. The Gas chromatography–mass spectrometry (GC-MS) reaction was done to identify the active compounds of qurraid aqueous extract. The ability of the aqueous extract of qurraid to manufacture silver nanoparticles was tested, and the construction of silver nanoparticles was inferred by the reaction mixture's color, which ranged from yellow to dark brown. The synthesi
... Show MoreA new copolymer (MFA) was prepared from condensation of melamine (M) with p- methyl – anisole (A) in the presence of condensation agent like 37% (w/v) of formaldehyde. The new copolymer was characterized by elemental, IR and HNMR spectra. The chelating ion-exchange property of this polymer was studied for methylene blue dye in aqueous solution in 100-200ppm concentrations. The adsorption study was carried out over a wide range of pH, shaking time and in media of various kinetic parameters models. Thermal parameters like enthalpy, entropy and Gibbs free energy of adsorption process of methylene blue on surface of MFA resin were determined on the basis of kinetic parameters at different temperatures. To describe the equilibrium of adsorp
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Heavy-duty diesel vehicle idling consumes fossil fuel and reduces atmospheric quality at idle period, but its restriction cannot simply be proscribed. A comprehensive tailpipe emissions database to describe idling impacts is not yet available. This paper presents a substantial data set that incorporates results from DI multi-cylinders Fiat diesel engine. Idle emissions of CO, hydrocarbon (HC), oxides of nitrogen (NOx), smoke opacity, carbon dioxide (CO2) and noise have been reported, when three EGR ratios (10, 20 and 30%) were added to suction manifold.
CO2 concentrations increased with increasing idle time and engine idle speed, but it didn’t show clear effect for IT adva
... Show MoreDouble hydrothermal method was used to prepare nano gamma alumina using aluminum nitrate nano hydrate and sodium aluminate as an aluminum source, CTAB (cetyltrimethylammonium bromide) as surfactant, and variable acids: weak acids like; citric, and acitic acids, and strong acids like; hydrochloric and nitric acids as a bridge between aluminum salts and surfactant. Different crystallization times 12, 24, 48, and 72 hrs were applied. All the batches were prepared at pH equals to 9. XRD diffraction technique was used to investigate the crystalline nano gamma alumina pure from surfactant. N2 adsorption-desorption (BET) was used to measure the surface area and pore volume of the prepared nano alumina, the average p
... Show MoreBackground: In human life, malnutrition may adversely affect various aspects of growth at different stages of life. Teeth are particularly sensitive to malnutrition. Malnutrition may affect odontometeric measurement involving arch width and length of primary dentition. The aim of this study is to estimate the effect of nutrition on arch width and length dimension measurements among children aged 5 years old. Material and methods: This study was conducted among malnourished group in comparison to well-nourished group matching with age and gender. The present study included 158 children aged 5 years (78 malnourished and 80 well-nourished). The assessment of nutritional status was done by using three nutritional indicators, namely Height-for-a
... Show MoreThe quantum chromodynamics theory approach was taken to study the photonic emission from interaction of quark gluon at high at Bremsstrahlung processes. Strength coupling, quark charge 𝑒𝑞 , flavor number 𝑛𝐹 , thermal energy T of system, fugacity of gluon ƛ𝑔, fugacity of quark ƛ𝑞 , critical temperature 𝑇𝐶 and photons energy 𝐸 are taken to calculate photons rate via the quantum system. Photons emission rate studies and calculates via high energy 400MeV to 650 MeV using flavor number 3 and 7 for 𝑢̅𝑔 → 𝑑̅𝑔𝛾 and 𝑐𝑔 → 𝑠𝑔𝛾 systems at bremsstrahlung processes with critical temperature (𝑇𝑐 = 190 and 196) MeV with photons energy (1-10) GeV. The confinement and de-confineme
... Show MoreIn this work, excess properties (eg excess molar volume (VE), excess viscosity (ȠE), excess Gibbs free energy of activation of viscos flow (ΔG* E) and molar refraction changes (ΔnD) of binary solvent mixtures of tetrahydrofurfuryl alcohol (THFA) with aromatic hydrocarbons (benzene, toluene and p-xylene) have been calculated. This was achieved by determining the physical properties including density ρ, viscosity Ƞ and refraction index nD of liquid mixtures at 298.15 K. Results of the excess parameters and deviation functions for the binary solvent mixtures at 298.15 K have been discussed by molecular interactions that occur in these mixtures. Generally, parameters showed negative values and have been found to fit well to Redlich-Kister
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