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Thermal performance of a flat-plate solar collector using aqueous colloidal dispersions of graphene nanoplatelets with different specific surface areas
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The effects of using aqueous nanofluids containing covalently functionalized graphene nanoplatelets with triethanolamine (TEA-GNPs) as novel working fluids on the thermal performance of a flat-plate solar collector (FPSC) have been investigated. Water-based nanofluids with weight concentrations of 0.025%, 0.05%, 0.075%, and 0.1% of TEA-GNPs with specific surface areas of 300, 500, and 750 m2/g were prepared. An experimental setup was designed and built and a simulation program using MATLAB was developed. Experimental tests were performed using inlet fluid temperatures of 30, 40, and 50 °C; flow rates of 0.6, 1.0, and 1.4 kg/min; and heat flux intensities of 600, 800, and 1000 W/m2. The FPSC’s efficiency increased as the flow rate and heat flux intensity increased, and decreased as inlet fluid temperature increased. When using nanofluids in the FPSC, the measured temperatures of absorber plate and tube wall decreased down to 3.35% and 3.51%, respectively, with the increase in weight concentration and specific surface area, while the efficiency increased up to 10.53% for 0.1- wt% TEA-GNPs nanofluid with specific surface area of 750 m2/g, in comparison with water. When using water as heat transfer fluid, very good agreement was obtained between the experimental and predicted values of absorber plate temperature, tube wall temperature, and collector’s efficiency with maximum differences of 3.02%, 3.19%, and 3.26%, respectively. While, when using nanofluids, higher differences were found, up to 4.74%, 4.7%, and 13.47% for TEA-GNPs nanofluid with specific surface area of 750 m2/g, respectively. Accordingly, the MATLAB code was capable of simulating the thermal performance of FPSCs utilizing nanofluids as their heat transfer fluids with acceptable accuracy. Values of performance index were all greater than 1, and increased as weight concentration increased up to 1.104 for 0.1- wt% TEA-GNPs nanofluid with specific surface area of 750 m2/g, implying higher positive effects on efficiency than negative effects on pressure drop. Accordingly, the investigated nanofluids can efficiently be used in FPSCs for enhanced energy efficiency, and the 0.1- wt% water-based TEA-GNPs nanofluid with specific surface area of 750 m2/g was comparatively the superior one.

Crossref
Publication Date
Fri Jan 05 2024
Journal Name
Al-academy
References of the directed education to the Member Teaching Stuff performance in the departments of the art Education
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This study has came as a result to discover on the references of the educational theories which leads the professors in the educational art departments in the Iraqi universities through knowing these ideological references indeed in an important slice of the society. This slice is: the members of professoriate. The study goal knows the ideological references to these theories for the professors in these departments.
In order to approve the research's goals. The researcher has selected a sample contains (50) professoriate members in these departments in the Iraqi universities which they have the educational art profession among the next scientific degrees (assistant teacher. teacher. assistant professor & professor).
The resea

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Publication Date
Wed May 12 2021
Journal Name
Indian Journal Of Forensic Medicine & Toxicology
The Relationship of Healthy Rationalist Pundit Thinking to the Spiking and Block Performance of Volleyball For Junior Players
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Crossref
Publication Date
Mon Feb 01 2016
Journal Name
Journal Of Engineering
The Effect of Cement and Admixture Types on the Resistance of High Performance Concrete to Internal Sulphate Attack
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This work is concerned with the study of the effect of cement types, particularly OPC and SRPC, which are the main cement types manufactured in Iraq. In addition, study the effect of mineral admixtures, which are HRM and SF on the resistance of high performance concrete (HPC) to internal sulphate attack. The HRM is used at (10%) and SF is used at (8 and 10)% as a partial replacement by weight of cement for both types. The percentages of sulphate investigated are (1,2 and 3)% by adding natural gypsum as a partial replacement by weight of fine aggregate. The tests carried out in this work are: compressive strength, flexural strength, ultrasonic pulse velocity, and density at the age of 7, 28, 90 and 120 days.

The r

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Publication Date
Wed Feb 26 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The role of Nano-Accounting in the Rationalization of Accounting Performance: بحث تطبيقي في الشركة العامة للصناعات الكهربائية
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The research Reviews the sides of highlight importance of the Nano-Accounting which doing the accounting performance functions fully computerized without the intervention of an accountant, to solve the problem of not keeping up the  rationalization of recording and accounting systems, with the rationalization of production which fully computerized.(be invisible and hidden accounting), resulting by linking or interaction of the accounting, additive production system represented three-dimensional printers, open source and recycling. That which result the rationalizing the facilities of production, organization and self-control which derived nanotechnology idea, which aims to minimize materials and change it properties, then view the a

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Publication Date
Tue Mar 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
Effect of Financial Performance of Jordanian Islamic Banks In the Amman Stock Exchange for the period (1990-2008)
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The last four decades have witnessed a number of rapid and successive international changes in terms of future impacts and orientations. International economy has transformed into a competitive small village due to the information technology revolution and the liberation processes and the economic openness that the market witnesses, there became one market and the activists in this international market are not governments only but rather international organizations and huge multinational corporations where each spares no effort to take every opportunity and face challenges within the frame of  removing all impediments and release transactions under the auspices of  these global developments, the idea of creating Islamic

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Crossref
Publication Date
Fri Mar 28 2025
Journal Name
Journal Of Physical Education
The effect of the four-pillar strategy on the performance of the transmission and preparation skills in volleyball
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The aim of the research is to prepare practical volleyball lessons by using the four pillars strategy for middle school students, and to identify the effect of the four pillars strategy in performing the transmission and volleyball skills in the second intermediate students, to assume that the two researchers assume that there are no statistically significant differences between the results of my skill performance tests Sending and preparing tribal and remote volleyball for the experimental and controlled groups, and there are no statistically significant differences between the results of the performance of the transmission and preparation skills of the volleyball between the two experimental and control groups, and the research co

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Crossref
Publication Date
Wed Jun 01 2022
Journal Name
Res Militaris
The impact of the Corona pandemic on the financial performance of companies listed on the Iraqi Stock Exchange
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This research aims to demonstrate the nature and concept of the Corona pandemic, its implications for the global economy, and the management and performance of companies in particular. Additionally, the research intends to measure the impact of the Corona pandemic on companies' financial performance. Listed on the Iraqi Stock Exchange, which has finished compiling its year-end financial statements for 2019-2020. The investigation arrived at several findings, the most significant of which was that most businesses were not prepared for such a crisis technologically or to develop human resources to deal with this pandemic. In addition, most companies experienced a decrease in their financial performance as a direct result of the Corona pandemi

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Scopus (4)
Scopus
Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
The impact of not applying justice career empowerment in Jordanian government institutions on the performance of working women
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The study aimed to identify the reality of the application of the organizational equity empowerment at the Jordanian government institutions from the viewpoint of women employees in terms of each of the (delegation equity, training equity, appraisal equity, join in committees equity, participation in decision-making equity), and the impact of non-application of equity empowerment on performance.

Population of the study amounted (986) women employee, while the researcher distributed (340) questionnaire through a randomly sample method.

The study used the questionnaire as a tool to collect the data. And to ensure the reliability of the questionnaire has been calculated Cronbach's co

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Crossref
Publication Date
Sun Feb 28 2021
Journal Name
Journal Of Economics And Administrative Sciences
Perceived organizational support and impact on high performance Analytical research in the colleges of the University of Baghdad
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     The research tagged (Perceived Organizational Support in High Performance) deals with identifying the extent of the impact of perceived organizational support as an explanatory variable on high performance as a response variable for the purpose of reaching appropriate mechanisms that enable colleges of the University of Baghdad to exploit the perceived organizational support in achieving the required high performance and pursuit of its goals. The researcher relied on the descriptive and analytical approach in carrying out the research. An intentional sample was selected and reached (70) persons from the higher leadership of the colleges represented by (deans, assistants deans, heads of departments) that r

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Crossref
Publication Date
Sat Apr 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Tacit knowledge of auditors and their reflection on the effectiveness of the performance to some inspectors general offices
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This research aims to find out the extent the reflection of tacit knowledge dimensions (experience, skill, intuition, the ability to think) on Organizational performance of the offices of inspectors general dimensions (internal processes, growth and learning the focus, the focus on the customer) and the measurement and analysis of the type of impact the tacit knowledge of auditors on performance Organizational in inspectors general offices, the research seeks to diagnose the extent of awareness of Office Management knowledge implicit and the attention span of the administration in determining levels and performance levels, and the resolution means the main information-gathering adopted by the researcher, which, as well as his exp

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Crossref