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Exergy Analysis of a Domestic Refrigerator
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An energy and exergy thermodynamic analysis using EES program was done for a domestic refrigerator working with R-134a using vapor compression refrigeration cycle. The analysis deals with the system component, i.e. compressor, condenser, evaporator and the expansion device. The analysis depends on the entropy generation minimization approach to improve the refrigerator performance by exploring the optimum design points. These design points were derived from three different theories governing the entropy generation minimization using exergy analyzing method. These theories were first applied to find the optimum balance between the hot inner condenser area and the cold inner evaporator area of the refrigerator and between its hot and cold thermal conductances. Nine types of condensers were used according to its internal surface area and thermal conductance, in order to reach the minimum entropy generation in the refrigerator. The results showed that the compressor has the lowest exergy efficiency of 25%. The expansion device was the second component after the compressor with exergy efficiency of 92%, followed by the condenser with an efficiency of 93%. The evaporator was found to have an exergy efficiency of 98 %. The experimental tests were repeated for the nine condensers sizes with three different ambient temperatures 25℃, 30℃ and 35℃.  The exergy analysis showed that the design of the refrigerator mainly depends on thermal conductance calculations rather than the surface inner area estimation.

 

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Publication Date
Mon Jan 01 2018
Journal Name
Fme Transaction
The influence of frictional facing thickness on the contact pressure distribution of multi-disc dry clutches
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Publication Date
Sun Sep 15 2024
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of surface microhardness of enamel surface treated with Nano- HAP serum before and after bleaching
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Background: Although bleaching is typically considered a safe procedure, various investigations have found minor negative effects and changes in mineral composition. The aim was to Evaluate and compare the efficacy of using Nanohydroxyapatite serum on surface microhardness of enamel surface before and after bleaching with chemically cured Boost bleaching. Material and methods: ten sound human permanent upper and lower premolar teeth were used and their roots were removed 2 mm apically to the cementoenamel junction, the crowns were sectioned mesiodistally into two halves buccal and lingual/palatal, the buccal surface was further subdivided into two halves. The samples were embeded in an acrylic resin, resulting in 30 specimens divide

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Publication Date
Thu Apr 20 2017
Journal Name
International Journal Of Science And Research (ijsr)
Effect of Different Sealer Systems on the Resistance to Vertical-Root-Fracture of Endodontically Treated Tooth
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Abstract: An unfavorable complication of root canal is vertical root fracture. The aim of present study is to evaluate the vertical root fracture of treated teeth filled with gutta percha and Resilon obturating material using different sealers. Forty mandibular premolars used in the study. Canals randomly divided into four groups (n=10). Group-A eugenol-based (Endofill) sealer with gutta percha; GroupB epoxy-amine (AH Plus) sealer with gutta percha; Group-C resin-based (Real Seal) sealer with Resilon; or Group-D epoxide-based (Perma Evolution) sealer with gutta percha. Roots mounted vertically in cold cure acrylic blocks and subjected to vertical loading with a crosshead speed of 1mm ̸min. The point at which fracture of the roots occurred

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Publication Date
Mon Aug 01 2022
Journal Name
Baghdad Science Journal
Investigation of the Nuclear Structure of Some Ni and Zn Isotopes with Skyrme-Hartree-Fock Interaction
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The inelastic C2 form factors and the charge density distribution (CDD) for 58,60,62Ni and 64,66,68Zn nuclei has been investigated by employing the Skyrme-Hartree-Fock method with (Sk35-Skzs*) parametrization. The inelastic C2 form factor is calculated by using the shape of Tassie and Bohr-Mottelson models with appropriate proton and neutron effective charges to account for the core-polarization effects contribution. The comparison of the predicted theoretical values was conducted with the available measured data for C2 and CDD form factors and showed very good agreement.

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Publication Date
Sun Sep 06 2020
Journal Name
European Journal Of Dental Education
Evaluation of technology‐based learning by dental students during the pandemic outbreak of coronavirus disease 2019
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Publication Date
Sun Dec 31 2023
Journal Name
Biomedical And Pharmacology Journal
Extraction, Isolation and Structure Elucidation of Two Phenolic Acids from Aerial Parts of Celery and Coriander
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Celery and coriander are vastly applied in modern medicine and traditionally because various medicinal and nutritional benefits depend on their medicinal characteristics. The study aimed to detect, isolate and compare extracts contents of phenolic acids (caffeic and p-coumaric acids) in ethyl acetate fraction of fresh and dry aerial parts of coriander (Coriandrum sativum L.) and celery (Apium graveolens L.) of the Apiaceae family. The extraction of these constituents was carried out by maceration method using 70% ethanol and fractionation was done by using petroleum ether, and ethyl acetate. The existence of caffeic and p-coumaric acids in aerial part extracts of two plants was identified by thin-layer chromatography (TLC) and high-

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Publication Date
Thu Mar 03 2022
Journal Name
Arabian Journal For Science And Engineering
Experimental Study of Cuttings Transport Efficiency of Low Solid Bentonite Drilling Fluids Modified by Cellulose Nanoparticles
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Advancements in horizontal drilling technologies are utilized to develop unconventional resources, where reservoir temperatures and pressures are very high. However, the flocculation of bentonite in traditional fluids at high temperature and high pressure (HTHP) environments can lower cuttings transportation efficiency and even result in problems such as stuck pipe, decreased rate of penetration (ROP), accelerated bit wear, high torque, and drag on the drill string, and formation damage. The major purpose of the present research is to investigate the performance of low bentonite content water-based fluids for the hole cleaning operation in horizontal drilling processes. Low bentonite content water-based drilling fluids were formulated by re

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Publication Date
Fri Jan 01 2021
Journal Name
International Journal Of Agricultural And Statistical Sciences
Effect of benzyl adenine and meta-topolin on in vitro propagation of C-35 citrange rootstocks
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This study was carried out in Plant Tissue Culture Labs, College of Agricultural Engineering Sciences, University of Baghdad from November 2018 to June 2019. Fresh stem cuttings, 5 cm long were selected from 6-month old C-35 Citrange rootstock. Five concentrations of BA (0, 1, 1.5, 2 and 2.5 mg.L-1) were studied and addition of meta-Topolin (mT) at four concentrations (0, 1, 5 and 10 mg.L-1) was also studied to find out its effect individually on shoot number and shoot length in multiplication stage. Rooting media supplemented with four concentrations of IBA (0, 1, 2 and 3 mg.L-1) was also studied to find out its effect on rooting percentage, root number and root length. Results showed that BA as concentration of 2.5mg.L-1 significantly gav

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Publication Date
Tue Aug 11 2020
Journal Name
Bdj Open
An in vitro assessment of the physical properties of manually- mixed and encapsulated glass-ionomer cements
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Abstract<sec> <title>Objectives

The last decade has seen a variety of modifications of glass-ionomer cements (GICs), such as inclusion of bioactive glass particles and dispensing systems. Hence, the aim was to systematically evaluate effect of mixing modes and presence of reactive glass additives on the physical properties of several GICs.

Materials and methods

The physical properties of eight commercial restorative GICs; Fuji IX GP Extra (C&H), KetacTM Fill Plus Applicap (C&H), Fuji II LC (C&H), Glass Carbomer Ce

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Publication Date
Sun Dec 09 2018
Journal Name
Baghdad Science Journal
On Free Resolution of Weyl Module and Zero Characteristic Resolution In The Case of Partition (8,7,3)
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