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Investigation of phase change characteristics for refrigerant R-134a flow in a double pipe heat exchanger with the use of thermal non-equilibrium model
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Almost all thermal systems utilize some type of heat exchanger. In a lot of cases, evaporators are important for systems like organic Rankine cycle systems. Evaporators give a share in a large portion of the capital cost, and their cost is significantly attached to their size or transfer area. Open-cell metal foams with high porosity are taken into consideration to enhance thermal performance without increase the size of heat exchangers. Numerous researchers have tried to find a representation of the temperature distribution closer to reality due to the different properties between the liquid and solid phases. Evaporation heat transfer in an annular pipe of double pipe heat exchanger (DPHEX) filled with cooper foam is investigated numerically with utilizing the local thermal non-equilibrium (LTNE) model. Warm water with constant inlet conditions flows in the inner pipe while R143a is used as cooling fluid in the annular pipe. The effects of pores per inch (PPI), mass flux of R134a and copper foam porosity on solid and fluid temperatures, liquid saturation and heat transfer coefficient are analysed and illustrated. Forchheimer-extended Darcy flow model is utilized with the adopting of the two-phase mixture model (TPMM). The governing equations in two-dimensional steady state regime were written in LTNE model. These equations were discretized using the finite volume method and a MATLAB program was built to solve these equations with its initial and boundary conditions. The obtained data illustrates that LTNE effect in metal foam is important for lower porosity, lower pore density and higher mass flux. The ratio of liquid will arrive its lowest value at the outlet, and it decreases with PPI increase and it increases with porosity and mass flux increase. The mean heat transfer coefficient approximately doubled when PPI increased from 10 to 50 and it increased by 70% when porosity decreased from 0.95 to 0.85.

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Publication Date
Sat Aug 30 2014
Journal Name
Chemistry And Materials Research
Synthetic, Spectroscopic And Antibacterial Studies Of Fe(II),Co(II),Ni(II),Cu(II),Zn(II),Cd(II)and Hg (II),Mixed Ligand Complexes Of Saccharin And Amoxicillin(antibiotics)
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Mixed ligand complexes of bivalent metal ions, viz; M= Fe(II),Co(II),Ni(II),Cu(II), Zn(II), Cd (II), and Hg(II) of the composition Na2[M (Amox)(Sac)3] in 1:1:3 molar ratio, (where Amox = Amoxicillin tryhydrate (C16H19N3O5S.H2O) and Sac = Saccharine(C7H5NO3S) have been synthesized and characterized by repeated melting point determination, Solubility, Molar conductivity, determination the percentage of the metal in the complexes by flame(AAS), FT-IR, magnetic susceptibility measurements and electronic spectral data. The ligands and their metal complexes have been screened for their biological activity against selected microbial strains (gram +ve) and (gram -ve).

Publication Date
Tue May 13 2014
Journal Name
International Journal Of Chemical And Process Engineering Research
SYNTHESIS, PHYSICO-CHEMICAL AND ANTIMICROBIAL PROPERTIES OF SOME METAL (II) -MIXED LIGAND COMPLEXES OF TRIDENTATE SCHIFF BASE DERIVES FROM Β-LACTAM ANTIBIOTIC {(CEPHALEXIN MONO HYDRATE)-4-CHLOROBENZOPHENONE} AND SACCHARIN
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A new Schiff base (4-chlorophenyl)(phenyl methanimine (6R,7R)-3-methyl-8-oxo-7-(2-phenylpropanamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate=HL=C29H24ClN3O4S) has been synthesized from β-lactam antibiotic (cephalexin mono hydrate (CephH)=(C16H19N3O5S.H2O) and 4- chlorobenzophenone. Metal mixed ligand complexes of the Schiff base were prepared from chloride salt of Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), in 50% (v/v) ethanol – water medium in aqueous ethanol(1:1) and Saccharin(C7H5NO3S) containing sodium hydroxide. Several physical tools in particular; IR, C:H:N , 1H NMR,13C NMR for ligand, melting point, molar conductance, magnetic moment. and determination of the percentage of the metal in the complexes by flame(AAS

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Publication Date
Wed Jan 01 2014
Journal Name
International Journal Of Technical Research And Applications
SYNTHESIS, PHYSICO-CHEMICAL AND ANTIMICROBIAL PROPERTIES OF SOME METAL (II) -MIXED LIGAND COMPLEXES OF TRIDENTATE SCHIFF BASE DERIVES FROM Β-LACTAM ANTIBIOTIC {(CEPHALEXIN MONO HYDRATE)-4-CHLOROBENZALDEHYDE} AND SACCHARIN
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new Schiff base 4-chlorophenyl)methanimine (6R,7R)-3-methyl-8-oxo-7-(2-phenylpropanamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate= (HL)= C23H20 ClN3O4S) has been synthesized from β-lactam antibiotic (cephalexin mono hydrate(CephH)=(C16H19N3O5S.H2O) and 4-chlorobenzaldehyde . Figure(1) Metal mixed ligand complexes of the Schiff base were prepared from chloride salt of Fe(II),Co(II),Ni(II),Cu(II),Zn(II) and Cd (II), in 50% (v/v) ethanol –water medium (SacH ) .in aqueous ethanol(1:1) containing and Saccharin(C7H5NO3S) = sodium hydroxide. Several physical tools in particular; IR, CHN, 1H NMR, 13C NMR for ligand and melting point molar conductance, magnetic moment. and determination the percentage of the metal in the complexes by fl

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Publication Date
Fri Mar 24 2023
Journal Name
Arab World English Journal
PRAGMATIC AWARENESS OF SPEECH ACTS, POLITENESS, AND GRICE MAXIMS OF IRAQI EFL POSTGRADUATE STUDENTS الوعي التداولي بأفعال الكلام والتأدب والاقوال المأثورة لطلبة الدراسات العليا العراقيين في اللغة الانجليزية كلغة اجنبية
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This study examines postgraduate students’ awareness of pragmatic aspects, including Grice Maxims, Politeness, and Direct and Indirect forms of speech. According to Paul Grice’s theory of implicature, which is considered one of the most important contributions to pragmatics, this paper discusses how postgraduate students can meet the cooperative principle when communicating effectively. It also outlines how does politeness principles influence obeying or violating the maxims and how is the use of direct or indirect forms of utterances prompted by politeness. Sixteen master’s students of Linguistics and Literature were asked to take a multiple-choice test. The test will be represented along with the interpretation of each optio

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Publication Date
Wed May 01 2024
Journal Name
Journal Of Physics: Conference Series
Effect of Sulfur on Characterization of AgInSe<sub>1.8</sub>S<sub>0.2</sub> Thin Film and n-AgInSe<sub>1.8</sub>S<sub>0.2</sub> / p-Si Solar Cell
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Abstract Ternary Silver Indium selenide Sulfur AgInSe1.8S0.2 in pure form and with a 0.2 ratio of Sulfur were fabricated via thermal evaporation under vacuum 3*10-6 torr on glasses substrates with a thickness of (550) nm. These films were investigated to understand their structural, optical, and Hall Characteristics. X-ray diffraction analysis was employed to examine the impact of varying Sulfur ratios on the structural properties. The results revealed that the AgInSe1.8S0.2 thin films in their pure form and with a 0.2 Sulfur ratio, both at room temperature and after annealing at 500 K, exhibited a polycrystalline nature with a tetragonal structure and a predominant orientation along the (112) plane, indicating an enhanced de

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Publication Date
Sat Dec 31 2022
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
EFFECT OF ADDITION RAW BACTERIOCIN PRODUCED BY Lactobacillus delbrueckii Sub-Sp. bulgaricus ON SOFT CHEESE: EFFECT OF ADDITION RAW BACTERIOCIN PRODUCED BY Lactobacillus delbrueckii Sub-Sp. bulgaricus ON SOFT CHEESE
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ABSTRACT

         The effect of adding raw bacteriocin produced by Lactobacillus bulgaricus to cheese curd at an amount of (5 and 10 and 15) mL/kg cheese as a biological preservative to prolong the shelf life of soft cheese, in addition to the control treatment, knowing that each 1 mL of bacteriocin filter contains 15 units/ mL of bacteriocin. The results of the physicochemical, microbial and sensory tests for cheese stored at refrigerator temperature for a period (zero) to (21) d of adding bacteriocin showed the superiority of the treatment of cheese added to 15 mL/kg cheese of bacteriocin over the rest of the other treatments during the storage period, wh

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Publication Date
Wed Oct 25 2023
Journal Name
College Of Islamic Sciences
Conjunction meaning and applied models
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It is no secret to anyone the lofty classifications and wonderful investigations made by Muslim scholars in various eras, with which they removed the dust of ignorance from the nation, clarified the argument, and illuminated the path of education, especially in the legal sciences, which are the foundation of religion.

It is the life of hearts and the path of grammarians in this world and the hereafter.

Among those scientific classifications are the investigations they have written in the science of the principles of legislation, which have established the general evidence and the original rules to which practical legal rulings are referred. And as you know, it is the basis of Islamic jurisprudence, a means of knowing its

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Publication Date
Tue Jun 09 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Selected salivary constituents, physical properties and nutritional status in relation to dental caries among 4-5 year’s old children (Comparative study)
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Background: Tooth decay is still one of most common diseases of childhood, child’s primary teeth are important even though they aretemporary. This study was conducted to assess the physiochemical characteristic of saliva among caries experience preschool children and compared them with caries free matching in age and gender. Then an evaluation was done about these salivary characteristics to dental caries and evaluated the relation of body mass index to dental caries and to salivary variables. Materials and method: After examination 360 children aged 4-5 years of both gender. Caries-experiences was recorded according to dmfs index by (World Health Organization criteria 1987) during pilot study children with caries experience was di

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Publication Date
Tue Dec 15 2020
Journal Name
Al-academy
Novel Coronavirus Pandemic as it is Expressed by Children in Their Drawings On-line: An Analytical Study: نزار بن صالح أحمد عبد الحفيظ
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This study aimed at identifying how children express the emerging coronavirus in general and according to their age groups (4-13 years) by analyzing 91 of their drawings published online, using the descriptive content analytical approach. The results showed that children's artistic expression of the virus came according to the concepts and ideas they carried about the virus for the age groups of (4-7 years) and (7-9 years), while it came according to visual perception for age groups (9-11 years), and from (11-13) years. Also, most children were aware about the presence of the virus and its widespread around the world, but (99%) of them do not realize the seriousness of the virus. It was confirmed that between (25-34%) of children were su

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Publication Date
Wed Jul 29 2020
Journal Name
Frontiers In Physiology
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) in Human Lung Microvascular Endothelial Cells Controls Oxidative Stress, Reactive Oxygen-Mediated Cell Signaling and Inflammatory Responses
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