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alkej-232
Influences of the Twisted Strips Insertion on the Performance of Flat Plate Water Solar Collector
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Abstract

    In order to enhance the efficiency of flat plate solar water collectors without changing in its original shape and with low additional cost, twisted strips are inserted inside its riser pipes. Three flat plate collectors are used for test. Family of twisted strips are inserted inside each collector risers with different twisted ratios (TR=3,4,5). The collectors are connected in parallel mode (Z-Configuration) and are exposed to the same conditions (solar radiation and ambient temperature) .The experimental results show that, the highest heat transfer rate occurs at twisted ratio (3) .Consequently, for the same twisted ratio the daily efficiencies for the solar collector at different flow rate used (60,100 and 150) ℓ /hr. were 49 %, 57% and 63% respectively.

 Keywords: Twisted strip, solar collectors.

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Publication Date
Fri Jul 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Performance Evaluation for Higher and Medium Leadership in Institutional Work Quality.
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This Research aims to define role of the system of evaluating the performance for higher leadership in determining the level of institutional work quality in the Ministry of Agriculture, by measuring system efficiency of evaluating the performance for higher leadership and its effect in institutional work quality, the searcher reached through the theoretical framing and involved studies to build default plan define the relation between Research variables formed from system of evaluating leadership performance as independent variable contains six subsidiary dimensions: (Polarization, evaluating the performance of personnel, training, motivation, se

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Publication Date
Wed Jun 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Performance evaluation of small and medium-sized enterprises according to the entrance of the scorecard applied study in company Al fadly for construction industries
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The research Aim is to provide support to small enterprises by providing tools that enable measurement and test their performance and identifying weaknesses and work on them is determined by the problem of searching using traditional assessment methods for small projects with only financial performance measurement standards that do not provide a complete picture of the performance of these projects so use the balanced scorecard the four pillars (financial, customer, learning and growth, and internal processes) and identify deviations and work on them through the use of the outputs of the programme (probe), PROmoting Business Excellence-PROBE), which It is a model of performance evaluation, with which you can deve

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Publication Date
Thu Mar 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of Intellectual trends on the nature of the Economic Structure of Iraq
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The Impact of Intellectual trends on the nature of the Economic Structure of Iraq

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Publication Date
Fri Sep 01 2023
Journal Name
Energy Reports
Effect of solvents on performance of Alq3/ZnO solar cells: A theoretical approach
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Successfully, theoretical equations were established to study the effect of solvent polarities on the electron current density, fill factor and efficiencies of Tris (8-hydroxy) quinoline aluminum (Alq3)/ ZnO solar cells. Three different solvents studied in this theoretical works, namely 1-propanol, ethanol and acetonitrile. The quantum model of transition energy in donor–acceptor system was used to derive a current formula. After that, it has been used to calculate the fill factor and the efficiency of the solar cell. The calculations indicated that the efficiency of the solar cell is influenced by the polarity of solvents. The best performance was for the solar cell based on acetonitrile as a solvent with electron current density of (5.0

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Publication Date
Thu Jun 08 2023
Journal Name
Iraqi Journal Of Laser
PDF Performance Study of Polarization Beam Splitters Based on Horizontal Slot Waveguide Operating at 700nm Wavelength
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Abstract: Polarization beam splitter (PBS) integrated waveguides are the key components in the receiver of quantum key distribution (QKD) systems. Their function is to analyze the polarization of polarized light and separate the transverse-electric (TE) and transverse-magnetic (TM) polarizations into different waveguides. In this paper, a performance study of polarization beam splitters based on horizontal slot waveguide has been investigated for a wavelength of . PBS based on horizontal slot waveguide structure shows a polarization extinction ratio for quasi-TE and quasi-TM modes larger than  with insertion loss below  and a bandwidth of . Also, the fabrication tolerance of the structure is analyzed.<

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Publication Date
Mon Sep 04 2023
Journal Name
East European Journal Of Physics
Investigation the Structural Influences of Silver Oxide Addition in the Bioactive Phosphate Glasses
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This research investigates the impact of varying concentrations of silver oxide on the structure and morphology of phosphate bioactive glass (PBG). PBGs are gaining popularity as a potential replacement for traditional silicate glasses in biomedical applications due to their adjustable chemical resistance and exceptional bioactivity. Upon examination of the scanning electron microscope of the composites without Ag2O, it was observed that the grains tended to merge together, and the surface particles appeared to be larger than those in composites with Ag2O at concentrations of 0.25, 0.5, and 0.75 wt%. The study found that the diffraction pattern of phosphate bioactive glass composites sintered without Ag2O showed the presence of Stro

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Publication Date
Thu Dec 01 2022
Journal Name
Al-khwarizmi Engineering Journal
BER Performance Improvement of Dual Chaotic Maps Based on STBC Communication System
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Sensitive information of any multimedia must be encrypted before transmission. The dual chaotic algorithm is a good option to encrypt sensitive information by using different parameters and different initial conditions for two chaotic maps. A dual chaotic framework creates a complex chaotic trajectory to prevent the illegal use of information from eavesdroppers. Limited precisions of a single chaotic map cause a degradation in the dynamical behavior of the communication system. To overcome this degradation issue in, a novel form of dual chaos map algorithm is analyzed. To maintain the stability of the dynamical system, the Lyapunov Exponent (LE) is determined for the single and dual maps. In this paper, the LE of the single and dual maps

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Publication Date
Mon Dec 31 2012
Journal Name
Al-khwarizmi Engineering Journal
The Effect of Doppler Phenomenon on the Speed of Blood Flow
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This research studying the phenomenon of Doppler (frequency Doppler) as a method through which the direction and speed of the blood cells flows in blood vessels wear measured. This Doppler frequency is relied upon in medicine for measuring the speed of blood flow, because the blood flow is an important concept from the concepts of medicine. It represents the function and efficient of the heart and blood vessels in the body so any defect in this function will appear as a change in the speed of blood flow from the normal value assumed. As this speed changes alot in cases of  disease and morbidity  of the heart, so in order to identify the effect of changing the Doppler frequency on the speed of blood flow and the relationship of

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Publication Date
Tue Feb 01 2022
Journal Name
Baghdad Science Journal
Effects of the Ferrits Addition on the Properties of Polyethylene Terephthalate
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The products of composites material are very sesetive to many variables, such as manufacturing process, additive materials, …. etc. Filler or additive plays a major role to determine the formation of the properties and behavior of the composites. In this study, polyethylene terephthalate-based compounds were produced and characterized. The work is concerned to prepare samples of Polyethylene terephthalate (PET) - zinc-ferrite (ZnFe2O4) with different addition ratio as zinc-ferrite (1, 2, 5, 10, 15 and 20) wt% obtained from mixing the solution with a hot pressing method applied under optimum conditions. The densities of the composites for all samples were calculated. Through the work the diffusion of zinc-ferrite i

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Publication Date
Sat Dec 30 2023
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of Green Training and Development on Sustainable Performance: An Analytical Research in the Ministry of Environment
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The current study aims to test the impact of green training and development on sustainable performance and explore its effects within and outside the Iraqi Ministry of Environment. The main research problem revolves around the question of the extent of implementing green training and development and sustainable performance in the ministry (What is the nature of the relationship between green training and development and sustainable performance in the ministry?). To clarify the relationship between the research variables, two main hypotheses were formulated along with sub-hypotheses. The study also aims to assess the level of the ministry's interest in the research variables and provide key recommendations to enhance sustainable performan

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