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Investigation of R134a Flow Boiling Heat Transfer and Pressure Drop in the Evaporator Test Section of Refrigeration System
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This paper presents an experimental and theoretical analysis to investigate the two-phase flow boiling heat transfer coefficient and pressure drop of the refrigerant R-134a in the evaporator test section of the refrigeration system under different operating conditions. The test conditions considered are, for heat flux (13.7-36.6) kW/m2, mass flux (52-105) kg/m2.s, vapor quality (0.2-1) and saturation temperature (-15 to -3.7) ˚C. Experiments were carried out using a test rig for a 310W capacity refrigeration system, which is designed and constructed in the current work. Investigating of the experimental results has revealed that, the enhancement in local heat transfer coefficient for relatively higher heat flux 36.6 kW/m2 was about 38% compared to 13.7 kW/m2 at constant operating conditions. The enhancement in heat transfer coefficient was about 57% when the mass flux increased from 52 kg/m2.s to 105 kg/m2.s at constant test conditions. The enhancement in the heat transfer coefficient was about 64% when the saturation temperature increased from -8 to -3.7 at fixed refrigerant mass velocity and heat flux. The effect of mass velocity on pressure drop was relatively higher by about 27% than that for heat flux at specified test conditions. The comparison between the experimental and theoretical results has shown an acceptable agreement with an average deviation of 21%.

 

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Estimation of Bladder pressure by using poiseuilles equation
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Equation Boizil used to Oatae approximate value of bladder pressure for 25 healthy people compared with Amqas the Alrotinahh ways used an indirect the catheter Bashaddam and found this method is cheap and harmless and easy

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Publication Date
Thu Feb 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
the administrative investigation and its impact on the performance of the offices of the inspectors General.
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The purpose of this research is to highlight the relationship between the   administrative investigation and the improvement of institutional performance, and the research sought to achieve a set of cognitive and applied goals. the administrative investigation is the modern trend of managing the offices of the general  hginspectors and the main source to build the necessary standards to manage and invest its resources efficiently and effectively required to achieve the goals it seeks. The institutional performance is the cornerstone for the implementation of all tasks and duties carried out by institutions operating within the borders of a particular country, The significant change

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Publication Date
Fri May 31 2024
Journal Name
Journal Of Interdisciplinary Mathematics
Fibrewise locally micro sliceable and fibrewise locally micro-section able micro-topological space
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The primary objective of this research be to develop a novel thought of fibrewise micro—topological spaces over B. We present the notions from fibrewise micro closed, fibrewise micro open, fibrewise locally micro sliceable, and fibrewise locally micro-section able micro topological spaces over B. Moreover, we define these concepts and back them up with proof and some micro topological characteristics connected to these ideas, including studies and fibrewise locally micro sliceable and fibrewise locally micro-section able micro topological spaces, making it ideal for applications where high-performance processing is needed. This paper will explore the features and benefits of fibrewise locally micro-sliceable and fibrewise locally

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
comparison between the methods estimate nonparametric and semiparametric transfer function model in time series the Using simulation
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 The transfer function model the basic concepts in the time series. This model is used in the case of multivariate time series. As for the design of this model, it depends on the available data in the time series and other information in the series so when the representation of the transfer function model depends on the representation of the data In this research, the transfer function has been estimated using the style nonparametric represented in two method  local linear regression and cubic smoothing spline method The method of semi-parametric represented use semiparametric single index model, With four proposals, , That the goal of this research is comparing the capabilities of the above mentioned m

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Publication Date
Wed Jan 01 2020
Journal Name
Indian Journal Of Ecology
Study on major constraints and problems in transfer of technology by agricultural extension organization
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Publication Date
Thu Dec 01 2022
Journal Name
Baghdad Science Journal
Synthesis, Characterization, and Investigation the Inhibitory Impact of Thiosemicarbazide Derivative toward the Corrosion of Mild Steel in Acidic Media
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        In this study we focused on the determination of influence the novel synthesized thiosemicarbazide derivative "2-(2-hydroxy-3-methoxybenzylidene) hydrazinecarbothioamide" (HMHC) influenced the corrosion inhibition of mild steel (MS) in a 1.0 M hydrochloric acid acidic solution.This is in an effort to preserve the metal material by maintaining it from corrosion.The synthesized inhibitor was characterized using elemental analysis, and NMR-spectroscopy. Then the corrosion inhibition capability of (HMHC) was studied on mild steel in an acidic medium by weight loss technique within variables [temperature, inhibitor concentration, and time]. The immersion periods were [1:00, 3:00, 5:00, 10:00, 24:00, and 72:00] hours and the tem

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Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
The Determinants of Total Factor Productivity Growth: an Analytical Study of a Cross Section of Countries for the Period (2003-2016)
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            This study tests the effect of a large number of independent variables that control the growth of the total productivity, which amounted to 112 variables, gathered from what is mentioned in the specialized theoretical and applied literature. The data for these variables were taken from global reports of sound international organizations and reliable databases covering the period 1991-2016. The data of the dependent variable, the growth of the total factor productivity, were taken from the database of the world development indicators. The study covered 61 countries for which data were available. The study included three regression models to explain

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Publication Date
Thu Dec 01 2016
Journal Name
Journal Of Engineering
Analytical and Experimental Investigation for the Effect of Air Injection Angle on the Performance of Airlift Pump
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The effect of air injection angle on the performance of airlift pump used for water pumping has been studied analytically and experimentally. An airlift pump of dimensions 42mm diameter and 2200 mm length with conventional and modified air injection device was considered. A modification on conventional injection device (normal air-jacket type) was carried out by changing injection angle from 90  (for conventional) to 45  and 22.5  (for modified). Continuity and one-dimensional momentum balance for the flow field with basic principle of two-phase flow and expressions of slip ratio and friction factor as function of flow rates were formulated. The analytical and experimental investigations were carried out f

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Publication Date
Tue Feb 05 2019
Journal Name
Journal Of The College Of Education For Women
System of governance and administration in the state of the Ottoman Algeria (1518-1830)
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Algeria is one of the states that are important to the Ottoman state, because of its geographic location is important to the Mediterranean Sea, as well as the economic resources of the nature of its soil geography and climate,diverse, making it the focus of attention of the Ottomans, along with the van, which has increased the interest of the Ottomans in Algeriais the fall Andalusat the hands of the Spaniardsin1492, and force the Muslims to get out of them, and did not Only Europeans do it, butrushed to the prosecution of Muslims tothe coast of North Africa and seizing control of manyofits ports and cities, prompting the Ottoman state to go forth and back to the barn Muslims,Especially after hehad appealed to the Arabs of the Ottoman sta

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Publication Date
Sun Jul 02 2017
Journal Name
Journal Of Educational And Psychological Researches
Test anxiety for intermediate level
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Test anxiety for intermediate level The current study aims to measure the test anxiety of research’s sample and to identify the statistical differences of test anxiety, considering two variables gender and students classes level (first and third intermediate class). To do this, a stratified random sampling of (300) student from first and third intermediate classes had selected from both the karkh and Rusafa sides of Baghdad province for the academic year 2015-2016. The author tested the whole sample by using the test anxiety scale that had tested for its validity and reliability. The results revealed that the research’s sample as a whole was suffering from test anxiety, there were a statistical differences between male and female tha

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