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Performance Evaluation of Small Scale Air-Conditioning System Using R22 and Alternative Refrigerants
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A mathematical model has been formulated to predict the influence of high outdoor air temperature on the performance of small scale air - conditioning system using R22 and alternative refrigerants R290, R407C, R410A. All refrigerants were investigated in the cooling mode operation. The mathematical model results have been validated with experimental data extracted from split type air conditioner of 2 TR capacity. This entailed the construction of an experimental test rig which consists of four main parts. They are, the refrigeration system, psychrometric test facility, measuring instrumentation, and auxiliary systems. The conditioned air was maintained at 25 0C dry bulb and 19 0C wet bulb for all tests. The outdoor ambient air temperature was varied from 35 0C to 55 0C in 5 0C increments. The study showed that R290 is the better replacement for R22 when the air conditioning system works under high ambient temperature. It has better performance as a drop in refrigerant. R407C has the closest performance to R22, followed by R410A.

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Publication Date
Sun May 01 2016
Journal Name
Journal Of Multidisciplinary Engineering Science Studies
The Thickness Effects Characterization Properties Of Copper Oxide Thin Films Prepared By Thermal Evaporation Technique
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In This paper, CuO thin films having different thickness (250, 300 , 350 and 400) nm were deposited on glass substrates by thermal vacuum evaporator. The thermal oxidation of this evaporated film was done in heated glass at temperature (300 in air at one hour. The study of X-ray diffraction investigated all the exhibit polycrystalline nature with monoclinic crystal structure include uniformly grains. Thin film’s internal structure topographical and optical properties. Furthermore, the crystallization directions of CuO (35.54 , 38.70 ) can be clearly observed through an X-ray diffraction analysis XRD, Atomic Force Microscope AFM (topographic image) showed that the surface Characteristics , thin films crystals grew with increases in either

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Publication Date
Tue Feb 02 2021
Journal Name
Asian Efl Journal
The Effect of Kagan`s PIES on Iraqi EFL Academic Students Achievement in Grammar Jigsaw
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The purpose of the current research is to investigate the impact of cooperative learning elements upon Iraqi EFL Academic learners` Educational outcomes in Syntactic proficiency. The hypothesis of current research is that there are no statistically significant differences between the mean score of experimental groups that used Kagan’s PIES (Positive reliance, Individual Accountability, equivalent cooperation, Simultaneous Interaction) and the control group that followed conventional method. In this study, the sample of the study is (30) university ESP learners were involved at college of Education. The control group (15) students were taught in conventional teaching whereas other (15) learners in experimental groups exposed to Kagan’s P

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Space-Charge Effect on the Theoretical Design of Electron Gun Operated under Zero Magnification Condition
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A computational investigation is carried out in the field of charged –particle optics with the aid of numerical analysis method using the personal computer. The work is concerned with the design of electron gun with space-charge effect. The Finite element method (FEM) used in the solution of Poison's equation for determine the axial potential distribution of the two-electrode immersion lens operated under zero magnification condition , and from the solution of the paraxial ray equation the optical properties such as the focal length , spherical and chromatic aberration coefficients are determined, also a calculation of the brightness and perveance for the lens. The electrodes geometry was determined in two and three dimensi

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Publication Date
Sat Jan 01 2022
Journal Name
International Journal Of Differential Equations
Dynamical Behaviours of Stage-Structured Fractional-Order Prey-Predator Model with Crowley-Martin Functional Response
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In this paper, the dynamic behaviour of the stage-structure prey-predator fractional-order derivative system is considered and discussed. In this model, the Crowley–Martin functional response describes the interaction between mature preys with a predator.  e existence, uniqueness, non-negativity, and the boundedness of solutions are proved. All possible equilibrium points of this system are investigated.  e su‰cient conditions of local stability of equilibrium points for the considered system are determined. Finally, numerical simulation results are carried out to con‹rm the theoretical results.

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Scopus
Publication Date
Sun Dec 07 2008
Journal Name
Baghdad Science Journal
Optium Conditions for the Production of Neutral Protease from local strain Aspergillus niger var cabonarius
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The optimum conditions for the production of neutral protease from local strain Aspergillus niger var carbonarius by solid – state fermentation system (Wheat bran) moisted with 0.2 M phosphate buffer (PH7.0) . the hydration ratio was 1:5 (V:W) . the concentration of inoculum was 1×106 spores per 10 gram of solid materials , initial P H 6.5 and 96 hours of incubation period at 30? C .the enzyme activity was 1300 unit / ml and specific activity was 1550 unit / mg protein .

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Publication Date
Thu May 02 2024
Journal Name
Iraqi Journal Of Applied Physic
Photosensitivity of Nb2O5/Si Thin Films Produced via DC Reactive Sputtering at Different Substrate Temperatures
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This study thoroughly investigates the potential of niobium oxide (Nb2O5) thin films as UV-A photodetectors. The films were precisely fabricated using dc reactive magnetron sputtering on Si(100) and quartz substrates, maintaining a consistent power output of 50W while varying substrate temperatures. The dominant presence of hexagonal crystal structure Nb2O5 in the films was confirmed. An increased particle diameter at 150°C substrate temperature and a reduced Nb content at higher substrate temperatures were revealed. A distinct band gap with high UV sensitivity at 350 nm was determined. Remarkably, films sputtered using 50W displayed the highest photosensitivity at 514.89%. These outstanding optoelectronic properties highlight Nb2O5 thin f

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Publication Date
Mon Feb 05 2024
Journal Name
J Contemp Med Sci | Vol. 10, No. 1, January–february 2024: 77–79
The Validity of Computed Tomography Guided Lung Tru-Cut Biopsies in Achieving Accurate Tissue Results
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Objective: This study aims to assess the efficacy of CT-guided true-cut biopsy as a less invasive and cost-effective diagnostic technique for peripherally placed lung lesions.

Publication Date
Sun Jun 06 2010
Journal Name
J Of Mustansiriya College Of Dentistry
the usefulness of Ramfjord teeth to represent the full-mouth pocket depth in epidemiology study
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Publication Date
Sun May 05 2024
Journal Name
Technium Business And Management
Measuring Blue Ocean Leadership activities in public organizations: field research in the Ministry of Communications
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This study aims to identify the level of application of blue ocean leadership activities in public organizations and to build a conceptual and cognitive framework around this concept. The study adopted a descriptive-analytical approach, and the research sample consisted of (95) individuals from the senior management working at the center of the Iraqi Ministry of Communications (director general, department manager, section head). The data analysis technique used is structural equation modeling (SEM) and the Statistical Package for the Social Sciences (SPSS). The results indicate that the senior management in the Ministry of Communications is working to adopt the blue ocean leadership style through its activities, but not to the leve

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Publication Date
Mon Sep 28 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Effect of Nd-YAG laser-irradiation on fluoride uptake by tooth enamel surface (In vitro)
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Background: The irradiation of teeth with a laser results in an interaction between the light and the biological constituents of the dental hard substance, which is converted directly into heat.This thermal effect is the cause of the structural and chemical enamel changes.The combined treatment of topical fluoride agent with laser may increase fluoride uptake, and reduce progression of caries-like lesions. The aim of this study was to measure the uptake of the acidulated phosphate fluoride and sodium fluoride to the buccal and lingual caries-like lesion enamel surfaces before and after irradiated by Nd-YAG laser in comparison with matching control group. Materials and methods: The sample consisted of 30 human healthy upper premolar teeth wh

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