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Absorber Diameter Effect on the Thermal Performance of Solar Steam Generator
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In this work, a convex lens concentrating solar collector is designed and manufactured locally by using 10 convex lenses (concentrator) of a diameter 10cm and one Copper absorber tube of a diameter 12.5mm and 1mm in thickness 1m length. Two axes manual Tracking system also constructed to track the sun continuously in two directions. The experiments are made on 17th of May 2015 in climatic conditions of Baghdad. The experimental data are fed to a computer program to solve the thermal performing equation, to find efficiency and actual useful energy. Then this data is used in numerical CFD software for three different absorber diameters (12.5 mm, 18.75 mm and 25 mm). From the results that obtained the maximum thermal efficiency for the collector of diameter 12.5mm equal to 82.3% is higher than that for the collector of 18.75 mm and 25 mm diameter. The maximum outlet temperature is found equal to (105C, 93.9C and 83.5C) for collector absorber diameter equal to (12.5 mm, 18.75mm and 25 mm) respectively. The maximum mass flow rate 0.53 kg/hr when the solar radiation intensity equal to 899 W/m2. The all-day collector efficiency varies with diameter and reaches to maximum value of (77.9%, 61.4% and 52.8) for collector diameter equal to (12.5 mm, 18.75mm and 25 mm) respectively.

 

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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
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
Developing Faculty Performance Competencies and their Reflection on Achieving Total Quality in Higher Education Institutions
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Total Quality Assurance Concept have appeared in Higher Education Institutions as a result of the continuous criticism for the lower quality of the outputs of these institutions and their inappropriacy to the needs of the job market. The faculty, i.e. teaching staff member, is one of the most important output for his/her responsibility to achieve the stated goals in higher education. This represents a problem that may influence the construction of society which has to limit his tasks, responsibilities, and competencies that should be found in a faculty, and evaluating his teaching profession in light of the prerequisites of the century to become an input to achieve quality assurance in Higher Education. Therefore, the present study aims

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Publication Date
Tue Sep 01 2015
Journal Name
Nano Science And Nano Technology
Preparation CuInSe2 (CIS) by arrested precipitation method as alight absorption layer of photovoltaic solar-cells
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The CuInSe2 (CIS) nanocrystals are synthesized by arrested precipitation from molecular precursors are added to a hot solvent with organic cap- ping ligands to control nanocrystal formation and growth. CIS thin films deposited onto glass substrate by spray - coating, then selenized in Ar- atmosphere to form CIS thin films. PVs were made with power conversion efficiencies of 0.631% as -deposited and 0.846% after selenization, for Mo coated, under AM 1.5 illumination. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analysis it is evident that CIS have the chalcopyrite structure as the major phase with a preferred orientation along (112) direction and the atomic ratio of Cu : In : Se in the nanocrystals is nearly 1 : 1 : 2

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Publication Date
Tue Jan 08 2019
Journal Name
Iraqi Journal Of Physics
Photoinduced interfacial charge transfer processes in solar photocatalysis degradation of methylene blue using nanostructured ZnO
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In this research, design of advanced material for sunlight conversion requires focused research to obtain efficient photocatalytic system. Nanostructured ZnO was synthesized using spin coating technique. The structural, morphological and optical properties of annealed nanostructured ZnO thin film at 390 Co for 3 hours were characterized by x-ray diffraction, atomic force microscope AFM and UV-VIS spectrophotometer. Nanostructured ZnO was applied for removal Methylene Blue (MB) dye from water using sunlight induced photocatalytic process. Overall degradation of MB/ZnO was achieved after 120 minutes of sunlight irradiation while it needs more time for MB alone. The reaction rate constant fit pseudo first order for MB/ZnO degradation was 0.

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Publication Date
Wed Dec 17 2025
Journal Name
Al-khwarizmi Engineering Journal
Numerical Analysis of Double Diffusive Laminar Natural Convection in a Right Angle Triangular Solar Collector
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Publication Date
Mon Oct 07 2024
Journal Name
Semiconductor Science And Technology
A facile method of deriving solar selective nickel-cobalt oxide thin films via spraying process
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Abstract<p>The present study focuses on synthesizing solar selective absorber thin films, combining nanostructured, binary transition metal spinel features and a composite oxide of Co and Ni. Single-layered designs of crystalline spinel-type oxides using a facile, easy and relatively cost-effective wet chemical spray pyrolysis method were prepared with a crystalline structure of M<sub>x</sub>Co<sub>3−x</sub>O<sub>4</sub>. The role of the annealing temperature on the solar selective performance of nickel-cobalt oxide thin films (∼725 ± 20 nm thick) was investigated. XRD analysis confirmed the formation of high crystalline quality thin films with a crystallite si</p> ... Show More
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Publication Date
Tue Nov 09 2021
Journal Name
Energies
Natural Convection Effect on Solidification Enhancement in a Multi-Tube Latent Heat Storage System: Effect of Tubes’ Arrangement
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The solidification process in a multi-tube latent heat energy system is affected by the natural convection and the arrangement of heat exchanger tubes, which changes the buoyancy effect as well. In the current work, the effect of the arrangement of the tubes in a multi-tube heat exchanger was examined during the solidification process with the focus on the natural convection effects inside the phase change material (PCM). The behavior of the system was numerically analyzed using liquid fraction and energy released, as well as temperature, velocity and streamline profiles for different studied cases. The arrangement of the tubes, considering seven pipes in the symmetrical condition, are assumed at different positions in the system, i

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Publication Date
Thu Oct 01 2020
Journal Name
Ieee Transactions On Very Large Scale Integration (vlsi) Systems
Low-Power, Highly Reliable Dynamic Thermal Management by Exploiting Approximate Computing
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With the continuous downscaling of semiconductor processes, the growing power density and thermal issues in multicore processors become more and more challenging, thus reliable dynamic thermal management (DTM) is required to prevent severe challenges in system performance. The accuracy of the thermal profile, delivered to the DTM manager, plays a critical role in the efficiency and reliability of DTM, different sources of noise and variations in deep submicron (DSM) technologies severely affecting the thermal data that can lead to significant degradation of DTM performance. In this article, we propose a novel fault-tolerance scheme exploiting approximate computing to mitigate the DSM effects on DTM efficiency. Approximate computing in hardw

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Publication Date
Fri Jan 01 2016
Journal Name
Applied Numerical Mathematics
Multiple time-dependent coefficient identification thermal problems with a free boundary
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Publication Date
Sun Jan 01 2017
Journal Name
Optics & Laser Technology
Finite element thermal analysis for PMMA/st.st.304 laser direct joining
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This work is concerned with building a three-dimensional (3D) ab-initio models that is capable of predicting the thermal distribution of laser direct joining processes between Polymethylmethacrylate (PMMA) and stainless steel 304(st.st.304). ANSYS® simulation based on finite element analysis (FEA) was implemented for materials joining in two modes; laser transmission joining (LTJ) and conduction joining (CJ). ANSYS® simulator was used to explore the thermal environment of the joints during joining (heating time) and after joining (cooling time). For both modes, the investigation is carried out when the laser spot is at the middle of the joint width, at 15 mm from the commencement point (joint edge) at traveling time of 3.75 s. Process par

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