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Performance Analysis of Four Conceptual Designs for the Air Based Photovoltaic / Thermal Collectors
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The  thermal  and  electrical  performance  of  different  designs  of  air  based  hybrid photovoltaic/thermal collectors is investigated experimentally and theoretically. The circulating air is used to cool PV panels and to collect the absorbed energy to improve their performance. Four different collectors have been designed, manufactured and instrumented namely; double PV panels without cooling (model I), single duct double pass collector (model II), double duct single pass (model III), and single duct single pass (model IV) . Each collector consists of: channel duct, glass cover, axial fan to circulate air and two PV panel in parallel connection. The temperature of the upper and lower surfaces of PV panels, air temperature, air flow rate, air pressure drop, wind speed, solar radiation and ambient temperature were measured. The power produced by solar cells is measured also. A theoretical model has been developed for the collector model IV based on energy balance principle. The prediction of the thermal and hydraulic performance was obtained for the fourth model of PV/T collector by developing a Matlab computer program to solve the numerical model. The experimental results show that the combined efficiency of model III is higher than that of models II and IV. The pressure drop of model III is less than that of models I and IV, by (43.67% and 49%). The average percentage error between the theoretical and experimental results was 9.67%.

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Publication Date
Sat Dec 30 2023
Journal Name
Journal Of Economics And Administrative Sciences
Employ the Knowledge Accumulation of Human Resources in Strategic Performance
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The main purpose of this research is to diagnose the role of the Knowledge Accumulation of Human Resources KAHR in Strategic Performance SP, and for that, the research was applied to the represented sample by the administrative leaders consisting of (108) individuals distributed according to their positions and the organizational structure of the ministry. Correlations, effects, and benefits from generalizing the results in the field of research. The research involved a mixed-methods approach through two stages. During the first stage, the researcher gathered quantitative data from a questionnaire. The second stage gathered qualitative data to explore the survey results more deeply by conducting individual interviews with a sub-sample of

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Publication Date
Sun Jan 13 2019
Journal Name
Iraqi Journal Of Physics
Porous Silicon effect on the performance of CdS nanoparticles photodetector
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Cadmium sulfide photodetector was fabricated. The CdS nano
powder has been prepared by a chemical method and deposited as a
thin film on both silicon and porous p- type silicon substrates by spin
coating technique. Structural, morphological, optical and electrical
properties of the prepared CdS nano powder are studied. The X-ray
analysis shows that the obtained powder is CdS with predominantly
hexagonal phase. The Hall measurements show that the nano powder
is n-type with carrier concentration of about (-5.4×1010) cm-3. The
response time of fabricated detector was measured by illuminating
the sample with visible radiation and its value was 5.25 msec. The
specific detectivity of the fabricated det

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Publication Date
Fri Jun 30 2017
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Study the Performance of Nanozeolite NaA on CO2 Gas Uptake
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The adsorption isotherms and kinetic uptakes of CO2 were measured. Adsorption isotherms were measured at two temperatures 309 K and 333 K and over a pressure range of 1 to 7 bar. Experimental data of CO2 adsorption isotherms were modeled using Langmuir, Freundlich and Temkin. Based on coefficient of correlation it was found that Langmuir isotherm model was well suited with the experimental data of CO2 adsorption isotherms.  In addition, Adsorption kinetic of CO2 mixture with N2 containing 10 % by volume CO2 and 90 % by volume N2 were determined in a temperature 36 °C and under the atmospheric pressure .When the flow rate was increased from

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Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
The role of internal audit in promoting social performance reports
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The research aims to demonstrate the impact of internal audit in Iraqi economic units on enhancing social performance reports, through the statistical models used, as a survey list (for the independent variant) of the search, which contains five axes of each axis, contains a set of The questions were prepared on the basis of the standards issued by the Institute of Internal Auditors (IIA) and were distributed to a sample of internal auditors, as for (for the approved variable) the researcher obtained numerical data represented by the financial statements of the research sample and used statistical models such as model (Kolmakrov-Smirnov) is a good match (goodness of fit) which assumes that the data is distributed naturally as wel

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Publication Date
Sat Mar 30 2013
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Studying the Performance of Refrigeration Units Powered by Solar Panel
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An experimental study was conducted to determine the performance of a solar electric refrigeration system. The system contained flat photovoltaic solar panel which absorbs the solar energy and convert it to electrical energy, used to run the refrigeration cycle. Two refrigeration cycles with electrical solar panel were used over a period of 12 months, the first one with classical parts known in refrigeration cycle, while the second one introduced heat exchanger which improves the coefficient of performance by saving the consumed energy. The coefficient of performance of these refrigeration cycles with compressor efficiency 85% are 2.102 and 2.57 respectively. The overall efficiency of the two systems are 18.9% and 23.13%.

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Publication Date
Wed Jul 01 2015
Journal Name
Journal Of Engineering
Enhancing the Performance of Piezoelectric Energy Harvesters Using Permanent Magnets
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A cantilevered piezoelectric beam with a tip mass at its free end is a common energy harvester configuration. This paper introduces a new principle of designing such a harvester which increases the generated voltage without changing the natural frequency of the harvester: The attraction force between two permanent magnets is used to add stiffness to the system. This magnetic stiffening counters the effect of the tip mass on the natural frequency. Three setups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle. Theoretical and experimental results show that magnetically stiffe

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Publication Date
Mon Mar 07 2022
Journal Name
Construction Research Congress 2022
Annual Revenue’s Influence on the Safety Performance of Construction Firms
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Publication Date
Thu Dec 26 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The impact of computerized planning on audit performance (Proposed model)
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The development of technology used in computerized programs is considered on of the most important topics that is responsible for creating tools that can be used in the business environment, the audit profession is one of those professions that received this development. In order for this profession to be more effective, there must be a tool based on sound (correct) scientific basis that can be based upon to enhance the quality of auditing. The research also aims to propose a computerized program to plan the auditing process according to the methods appropriate to the working environment in the audit offices and companies in Iraq. The computerized program was applied to the research sample and the hypothesis of the research has been prov

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Publication Date
Sat Apr 01 2023
Journal Name
Iop Conference Series: Earth And Environmental Science
Evaluating the Performance of Combined Equipment (RAU) and Field Tested
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Abstract<p>An experiment was carried out evaluate the performance of RAU combined equipment under three levels of practical speed, (V1) 4.06 km. h<sup>-1</sup>, (V2) 4.43 km. hr<sup>-1</sup> and (V3) 5.76 km. hr<sup>-1</sup>, and three levels of depth with 10,20and 30 cm. It is denoted by D1, D2, D3 respectively. A split plot design was used within the RCBD design with three replications. The experiment results showed that the first practical speed 4.06 km.hr<sup>-1</sup> achieved the lowest slippage percentage from 9.61%, lowest traction power 14.65hp, lowest soil penetration resistance to1.34 kg.cm<sup>-2</sup>, and the highest total operating </p> ... Show More
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Publication Date
Tue Dec 01 2020
Journal Name
Baghdad Science Journal
The Numerical Technique Based on Shifted Jacobi-Gauss-Lobatto Polynomials for Solving Two Dimensional Multi-Space Fractional Bioheat Equations
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This article deals with the approximate algorithm for two dimensional multi-space fractional bioheat equations (M-SFBHE). The application of the collection method will be expanding for presenting a numerical technique for solving M-SFBHE based on “shifted Jacobi-Gauss-Labatto polynomials” (SJ-GL-Ps) in the matrix form. The Caputo formula has been utilized to approximate the fractional derivative and to demonstrate its usefulness and accuracy, the proposed methodology was applied in two examples. The numerical results revealed that the used approach is very effective and gives high accuracy and good convergence.

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