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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
Tue Sep 11 2018
Journal Name
Iraqi Journal Of Physics
An experimental cross-section measurement of 10B(n,α)7Li reaction on counting alpha particles track density
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The present work determines the particle size based only on the number of tracks detected in a cluster created by a hot particle on the CR-39 solid state nuclear track detector and depending on the exposure time. The mathematical model of the cross section developed here gives the relationship between alpha particle emitting from the (n, α) reaction and the number of tracks created and distribution of tracks created on the surface of the track detector. In an experiment performed during this work, disc of boron compound (boric acid or sodium tetraborate) of different weights were prepared and exposed to thermal neutron from the source. Chemical etching is processes of path formation in the detector, during which a suitable etching solut

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Publication Date
Sat Sep 30 2017
Journal Name
College Of Islamic Sciences
Book of Musaka (by Imam Abu al-Qasim Abdul-Karim Muhammad ibn Abd al-Karim al-Rafii)
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Al-Aziz's book was chosen as a subject for research as it is one of the important books in the Islamic world in general and the Shafi'i school in particular and its author Imam Abdul Karim bin Mohammed bin Abdul Karim Al-Rafi's, who in the doctrine of the jurisprudence has made prominent lines and left behind invaluable scientific treasures in the service of religion. Its importance is summarized as follows:
1. Being an explanation of the book (brief) of the argument of Islam Imam Ghazali (God's mercy), one of the five books adopted in Shafi'i jurisprudence.
2. His work is Imam Abu al-Qasim al-Rafii known for the brilliance of the investigation and the power of weighting in the doctrine.
3. It is considered an encyclopedia in Sh

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Publication Date
Wed May 01 2019
Journal Name
Journal Of Engineering
Optimization of Friction Stir Welding Process Parameters to joint 7075-T6 Aluminium Alloy by Utilizing Taguchi Technique
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In this study, a 3 mm thickness 7075-T6 aluminium alloy sheet was used in the friction stir welding process. Using the design of experiment to reduce the number of experiments and to obtain the optimum friction stir welding parameters by utilizing Taguchi technique based on the ultimate tensile test results. Orthogonal array of L9 (33) was used based on three numbers of the parameters and three levels for each parameter, where shoulder-workpiece interference depth (0.20, 0.25, and 0.3) mm, pin geometry (cylindrical thread flat end, cylindrical thread with 3 flat round end, cylindrical thread round end), and thread pitch (0.8, 1, and 1.2) mm) this technique executed by Minitab 17 software. The results showed th

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Publication Date
Sat Jul 01 2023
Journal Name
Chemical Methodologies
Acid Activation of Iraqi Bentonite Clay and Studying its Structural, Dielectric and Electrical Behavior at Various Temperatures
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Iraqi calcium bentonite was activated via acidification to study its structural and electrical properties. The elemental analysis of treated bentonite was determined by using X-ray fluorescence while the unit crystal structure was studied through X-ray diffraction showing disappearance of some fundamental reflections due to the treatment processes. The surface morphology, on the other hand, was studied thoroughly by Scanning Electron microscopy SEM and Atomic Force Microscope AFM showing some fragments of montmorillonite sheets. Furthermore, the electrical properties of bentonite were studied including: The dielectric permittivity, conductivity, tangent loss factor, and impedance with range of frequency (0.1-1000 KHz) at different temperatu

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Publication Date
Fri Jul 01 2022
Journal Name
Civil Engineering Journal
Behavior of Post-Tensioned Concrete Girders Subject to Partially Strand Damage and Strengthened by NSM-CFRP Composites
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Studies on the flexural behavior of post-tensioned beams subjected to strand damage and strengthened with near-surface mounted (NSM) technique using carbon fiber-reinforced polymer (CFRP) are limited and fail to examine the effect of CFRP laminates on strand strain and strengthening efficiency systematically. Furthermore, a design approach for UPC structures in existing design guidelines for FRP strengthening techniques is lacking. Hence, the behavior of post-tensioned beams strengthened with NSM-CFRP laminates after partial strand damage is investigated in this study. The testing program consists of seven post-tensioned beams strengthened by NSM-CFRP laminates with three partial strand damage ratios (14.3% symmetrical damage, 14.3%

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Publication Date
Sun May 10 2020
Journal Name
Baghdad Science Journal
Characterization and Biological Activity of Some New Derivatives Derived from Sulfamethoxazole Compound: new derivatives from sulfamethoxazole drug.
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 A new series of Sulfamethoxazole derivatives was prepared and examined for antifibrinolytic and antimicrobial activities. Sulfamethoxazole derivatives bear heterocyclic moieties such as 1,3,4-thiadiazine {3},  pyrazolidine-3,5-diol {4} 6-hydroxy-1,3,4-thiadiazinane-2-thione {5} and [(3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-4-yl)diazenyl] {8}. Their structures were elucidated by spectral methods (FT-IR, H1-NMR). Physical properties are also determined for all compound derivatives.  Recently prepared compounds were tested for their antimicrobial activity in the laboratory. Each screened compound showed good tendency to moderate antimicrobial activity.

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Publication Date
Mon Jul 01 2019
Journal Name
Reviews In Medical Microbiology
Expression of virulence and antimicrobial resistance genes among Escherichia coli clinical isolates from blood and stool samples
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Objective:

As major nosocomial pathogens, Escherichia coli isolates exhibit antibiotic resistance and also express adhesive structures and antibiotic resistance genes. The objective of this study was the comparison of virulence gene expression of extended-spectrum beta-lactamase (ESBL)-producing E. coli between blood and stool samples.

Methods:

In this study, 20 E. coli clinical isolates (10 ESBL-producers including 5 from blood, 5 from stool sample

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Publication Date
Wed Jun 29 2022
Journal Name
College Of Islamic Sciences
Poetiness of Mohammad Almaghout,s Daily and familiar Writings ( Joy is not my profession ) is an Example
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Abstract

Our description of the wxperience of any poet depends on the nature the anture of his writing or his style in terms of factors affecting his experience . We have found that al- Maghout is characterized by important poetis properties that characterized all of his poetry such as the ease in compositions that are formed the vocabulary of daily life . This is what constitutes his poetic lexicon that depends on the vocabulary of space , time , and anture . Hispoetry derives its aesthetics from revealing that strains in the text for the sake of surprise and amazement with a simple realism.

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Publication Date
Wed Jun 01 2022
Journal Name
Journal Of Engineering
Extraction of Manganese Element from Electric Arc Furnace Steel Slag (EAFS) by Liquid-liquid extraction (LLE) method
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This research investigates manganese (Mn) extraction from Electric Arc Furnace Steel Slag (EAFS) by using the Liquid-liquid extraction (LLE) method. The chemical analysis was done on the slag using X-ray fluorescence, X-ray diffraction, and atomic absorption spectroscopy. This work consisted of two parts: the first was an extensive study of the effect of variables that can affect the leaching process rate for Mn element from slag (reaction time, nitric acid concentration, solid to liquid ratio, and stirring speed), and the second part evaluates the extraction of Mn element from leached solution. The results showed the possibility of leaching  83.5 % of  Mn element from the slag at a temperature of 25°C, nitric acid co

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Publication Date
Sun Apr 02 2017
Journal Name
International Workshop In Physics Applications
Antifungal activity of wide band gap Thioglycolic acid capped ZnS:Mn semiconductor nanoparticles against some pathogenic fungi(Article)
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The manganese doped zinc sulfide nanoparticles were synthesized by simple aqueous chemical reaction of manganese chloride, zinc acetate and thioacitamide in aqueous solution. Thioglycolic acid is used as capping agent for controlling the nanoparticle size. The main advantage of the ZnS:Mn nanoparticles of diameter ~ 2.73 nm is that the sample is prepared by using non-toxic precursors in a cost effective and eco-friendly way. The structural, morphological and chemical composition of the nanoparticles have been investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with energy dispersion spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy. The nanosize of the prepared nanoparticles was elucidated by Scan

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