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Natural convection in an annular space provided with metal foam fins attached to the inner cylinder is studied numerically. The metal foam fins made of copper were inserted in different axial sections with three fins in each section. The temperature of the inner cylinder is kept constant while the annular outer surface is adiabatic. The thickness effect of the inner pipe wall was considered. Naiver Stokes equation with Boussinesq approximation is used for the fluid regime while Brinkman-Forchheimer Darcy model is used for metal foam. In addition, the local thermal non-equilibrium condition in the energy equation of the porous media is presumed. The effect of Rayleigh number and number of foam fins in the axial direction, on fluid flow and heat transfer characteristics, were examined. The current model was valid with the available published results and good agreement is noticed. Results showed that as the Rayleigh number increases the dominated of convection mode increases and average Nusselt increases. It was found that at Rayleigh of 106 Nusselt reached its higher value which is 4.6 for the case of adding seven axial metal foams. A comparison between adding foam fins and copper fins was established for a range of Rayleigh numbers between 104 and 106. It showed a good enhancement in Nusselt number and the greatest enhancement percentage was 45.9% at Rayleigh equal 106 for the case of using seven sections of foam fins. |
Background: Health professionals have a crucial role in promotion, support and management of breastfeeding. To be effective in this effort, the clinician should focus on the issue from the preconception stage through pregnancy and delivery, and continue in subsequent infant care. Aim of the study: to assess the effectiveness of the UNICEF/WHO 40-hour of breast feeding training through the assess breastfeeding knowledge and attitudes of the health profession staff before and after training course.
Gymnastics is one of the most interesting games in terms of organizing various world championships and tournaments. Their basic skills and their technical development, especially those with high difficulty levels that rely on basic and complex skills, are the basic skills of gymnastics are the main pillar to be developed and therefore high-difficulty skills will not depend on basic skills, which should reach the stage of the automatic mechanism. Retention) in order to move on to training and developing another skill for the difficulty of movements as well as the smooth flow of performance, ie the degrees of difficulty of each skill specific to your gym and The researcher used the experimental method and The research community determin
... Show MoreThis work intends to develop an effective heavy metal-free modifier having properties comparable to traditional stabilizers and flame retardants, simultaneously being environmentally friendly and may be superior in many aspects. The important requirement focused on is: how to increase thermal stability and flame retardancy of flexible poly(vinyl chloride). Due to the typical materials now used with poly(vinyl chloride), which increases health and environmental concerns, utilizing a novel heavy metal-free additive will make poly(vinyl chloride) substantially safer. We have used an artificial silicate for this aim, which proved to be an efficient flame retardant and surprisingly showed excellent heat stabilizing effect. Thermal stabi
... Show MoreThis study aims to prepare new compounds and investigate them spectroscopically and biologically against selected types of positive and negative bacteria and fungi to demonstrate their biological effectiveness. The prepared ligand combining formaldehyde, indole, sulfa benzamide, and 2-mercapto benzimidazole, a Mannich base ligand (L) was synthesized. The six metal ions including Cobalt (II), Nickel (II), Copper (II), Palladium (II), Platinum (IV), and gold (III) have interacted with the ligand and formed new complexes. Different spectroscopic methods, including C.H.N.S., FTIR, UV- Range visible, 1HNMR, 13CNMR, mass spectra, magnetic moment, and molar conductivity were used to suggest the new geometry of the complexes. The resul
... Show MoreThe current study aimed to evaluate the effect of the heavy metals copper, cadmium and cobalt when added individually, in combination and in combination on the growth and reproduction of the aquatic fungus Saprolegnia hypogyna.
Reaction of  p-fluoro benzoic acid with the thiosemicarbazide and salcialdehyde gave the new bidentate ligand .The prepared ligand Identified by FT-I.R and U.V-Visible spectcopic technique .Treatment of the prepared   ligand   with following metal ions  M=Tb(III),Eu(III),Nd(III) and La(III) ,in ethanol with a (1:1) M:L ratio and at pH=7 yielded series of neutral complexes as the general formula  [M LCl (H O ]. The prepared complexes were characterized using (FT-IR, UV-Vis) spectra , melting point, molar conductivity measurements . chloride ion content were also evolution by (mhor method) . The proposed structure of the complexes using program , chem office 3D(2004) .
New azo ligand 2-((4-formyl-3-hydroxynaphthalen-2-yl) diazenyl) benzoic acid (H2L) was synthesized from the reaction of 2-aminobenzoic acid and2-hydroxy-1-naphthaldehyde. Monomeric complexes of this ligand, of general formulae [MII(L)(H2O)] with (MII = Mn, Co, Ni, Cu, Zn, Pd, Cd and Hg ) were reported. The compounds were isolated and characterized in solid state by using 1H-NMR, FT-IR, UV–Vis and mass spectral studies, elemental microanalysis, metal content, magnetic moment measurements, molar conductance and chloride containing. These studies revealed tetrahedral geometries for all complexes except PdII complex is Square planar. The study of complexes formation via molar ratio of (M:L) as (1:1). Theoretical treatments of compounds in gas
... Show MoreComplexes of 1-phenyl-3-(2(-5-(phenyl amino)-1,3,4- thiadiazole-2-yl)phenyl) thiourea have been prepared and characteized by elemental analysis, Ff-[R, and u.v./ visible spectra moreover, determination of metal content M%o by flame atomic absorption spectroscopy, molar conductance in DMSO solution and magnetic moments (peffl. The result showed that the ligand (L) was coordinated to Mn*2, Ni*2, Ct*2,2n*2,Cd*2, and Hg*2 ions through the nitrogen atoms and sulpher atoms. From the result obtained, rhe following general formula [MLClz] has been given for the prepared complexes with an octahedral geometry around the metal ions for all complexes. where M= Mn*2, Ni*2, cu*2, zn*z, cd*z, and Hg*2 l= l-phenyl-3-(2-(5-(phenyl amino)-1, 3,
... Show MoreComplexes of 1-phenyl-3-(2(-5-(phenyl amino)-1,3,4-thiadiazole-2-yl)phenyl) thiourea have been prepared and characteizedby elemental analysis, Ff-[R, and u.v./ visible spectra moreover,determination of metal content M%o by flame atomic absorptionspectroscopy, molar conductance in DMSO solution and magneticmoments (peffl.The result showed that the ligand (L) was coordinated to Mn+2, Ni+2,Ct+2,2n+2,Cd+2, and Hg+2 ions through the nitrogen atoms and sulpheratoms.From the result obtained, rhe following general formula [MLCl2] hasbeen given for the prepared complexes with an octahedral geometryaround the metal ions for all complexes.where M= Mn+2, Ni+2, cu+2, zn+2, cd+2, and Hg+2 l= l-phenyl-3-(2-(5-(phenyl amino
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