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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
Fri Nov 01 2013
Journal Name
International Journal Of Advanced Research
The effects of alkaloid extracted of Solanum nigrum leaves on the biological performance of Dialerodus citri
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Publication Date
Fri Jan 19 2024
Journal Name
Eximia
Job pressures affecting the quality of teachers’ performance at the College of Physical Education and Sports Sciences/University of Baghdad
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The research aimed to prepare a measure of job stressors affecting the quality of teaching performance in the College of Physical Education and Sports Sciences at the University of Baghdad, to identify their levels, if any, and the most influential dimensions on the quality of teaching performance within the college’s work environment, as well as the deanship’s ability to help prevent and Alleviating its severity through logical administrative methods, on a scale that includes four dimensions that include (the administrative and financial environment, the organizational environment, the social and humanitarian environment, and the scientific and research environment). The descriptive approach was adopted using the case study met

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Publication Date
Thu Mar 21 2024
Journal Name
International Development Planning Review
THE EFFECT OF USING A DISABLING FORCE TRAINING TOOL ON WALKING PERFORMANCE: AN ANALYTICAL STUDY OF TIME AND STEP LENGTH IN THE 20 KM WALKING RACE EVENT FOR APPLICANTS
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Publication Date
Tue Jun 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The impact of the empowerment strategy in the employees performance by mediating organizational trust (Field res
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The research aims to measure the impact of the empowerment strategy on the performance of employees by mediating organizational trust in the organization. The problem of research was the weak ability of most business organizations to employ the strategy of empowerment in maximizing the performance of employees, and the importance of research in practice lies in the results of a guide to managers in how to use the strategy of empowerment in maximizing the performance of employees by mediating organizational trust dimensions of ability, benevolence, integrity. In order to achieve the objectives of the research and to answer the questions of the problem, the researcher has adopted the descriptive analytical approach as the questionnaire was

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Publication Date
Sun Jun 07 2015
Journal Name
Baghdad Science Journal
On The Nearby-Tip Strain Investigation and Failure-Propability Evaluation for Impacted Thin Plates Using the 2-Random-Variables Multi-Canonical-Based Joint Propability Distributions
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The study of the validity and probability of failure in solids and structures is highly considered as one of the most incredibly-highlighted study fields in many science and engineering applications, the design analysts must therefore seek to investigate the points where the failing strains may be occurred, the probabilities of which these strains can cause the existing cracks to propagate through the fractured medium considered, and thereafter the solutions by which the analysts can adopt the approachable techniques to reduce/arrest these propagating cracks.In the present study a theoretical investigation upon simply-supported thin plates having surface cracks within their structure is to be accomplished, and the applied impact load to the

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Publication Date
Sun Jun 15 2025
Journal Name
Journal Of Physical Education
The Effect of Using Teaching Aid on the Development of Straight Forehand and Backhand Shot Performance in Lawn Tennis
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The problem of the research lies in finding aiding means that improve and facilitate learning artistic skills during the main part of a teaching sessions due to their great importance in developing the accuracy of forehand and backhand skills in tennis. Players are usually faced with difficulties at the beginning of learning due to lack of coordination in ball striking thus including a teaching aid will have a positive effect on learning some forehand and backhand skills. The research aimed at designing exercises using teaching aid in tennis as well as identifying the effect of these exercises on the accuracy of performing forehand and backhand shots in tennis. The researcher used the experimental method on (38) tennis players from Al Zewra

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Publication Date
Mon Jun 01 2015
Journal Name
Journal Of Engineering
Structural Systems for Modern Architecture in Iraq Analysis Study to Dr. Qahtan Al-Madfa’i’s Architecture
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Dr. Qahtan Al-Madfa’i’s architecture has been characterized by a particular characteristic that may be unique and extreme at the same time, that is the use of the distinctive three-dimensional structural coverings and the exploitation of structural construction to give an extra aesthetic touch to the composition of the building, to achieve the application of his universal ideas, which he strongly believed and defended.

      In the period of the marked urban decline that the country undergoes now, which urges us toward making a comparison between the beginning of the modern Iraqi architecture and its ascending path up to its peak and the periods of its decline until it reached a very

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Publication Date
Fri Mar 27 2020
Journal Name
Solid State Technology
Seepage and Slope Stability Analysis for Hemrin Earth Dam in Iraq Using Geo-Studio Software
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Publication Date
Mon Nov 28 2022
Journal Name
F1000research
In vitro apical microleakage evaluation for different endodontic sealers by spectrophotometric analysis: an observational study
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Background: It has been established that several filling techniques can affect apical leakage, which is responsible for 59% of endodontic failures. The primary goal of endodontic therapy is to create a tight seal that aids in repairing the periapical tissues, prevents apical periodontitis, and shields against root canal infection. The study aims to compare the apical sealing ability of epoxy resin based sealer  (AH plus), which is an epoxy-resin-based root canal sealer, GuttaFlow 2, which is a silicone-based root canal sealer, GuttaFlow bioseal is a bioactive glass-based root canal sealer, TotalFill HiFlow bioceramic (BC) sealer is a silicate-based root canal sealer (bioceramic sealer) using a single cone techn

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Publication Date
Wed Aug 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Proposed Measure for Effect Size in Mediation Analysis with Solution to Some Mediation Process Problems
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In this paper, the effect size measures was discussed, which are useful in many estimation processes for direct effect and its relation with indirect and total effects. In addition, an algorithm to calculate the suggested measure of effect size was suggested that represent the ratio of direct effect to the effect of the estimated parameter using the Regression equation of the dependent variable on the mediator variable without using the independent variable in the model. Where this an algorithm clear the possibility to use this regression equation in Mediation Analysis, where usually used the Mediator and independent variable together when the dependent variable regresses on them. Also this an algorithm to show how effect of the

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