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Enhancement of Heat Exchanger Performance by Using Dimpled Tube
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The enhancement of heat exchanger performance was investigated using dimpled tubes tested at different Reynolds numbers, in the present work four types of dimpled tubes with a specified configuration manufactured, tested and then compared performance with the smooth tube and other passive techniques performance. Two dimpled arrangements along the tube were investigated, these are inline and staggered at constant pitch ratio X/d=4, the test results showed that Nusselts number (heat transfer) of the staggered array is higher than the inline array by 13%.  The effect of different depths of the dimple (14.5 mm and 18.5 mm) has been also investigated; a tube with large dimple diameter enhanced the Nusselts number by about 25% for the range of Reynolds number between 4000- 20000. The overall enhancement ratio was used to differentiate the passive technique and comparison of different configurations for the technique itself, the result depicted that the 10 mm dimple diameter with a pitch ratio of X/d= 4 gives better performance than the static mixer and twisted tape techniques. The overall enhancement ratio of the 10 mm dimple diameter is varied from (1.21 to 1.65) that means good performance for a range of Reynolds numbers (4000-20000). This indicates that 21- 65 % of heat transfer area can be saved at the same pumping power compared with the smooth tube heat exchanger. 

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Publication Date
Sun Jun 20 2021
Journal Name
Journal Of Petroleum Research And Studies
The Influence of Glass Fiber and Milled Glass Fiber on the Performance of Iraqi Oil Well Cement
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The reinforced fiberglass in cement slurry reflects the effect on its properties compared to usual additives. Fiberglass is typically used in cement slurry design for one or another of the following goals: (Earth earthquake, bearing storage, and with differential stresses, to enhance cement durability and increase its compressive strength). The main goal is to use glass fiber and ground fiberglass to improve the tensile strength and moderate compressive strength significantly. On the other hand, the use of glass fibers led to a slight increase in the value of thickening time, which is a desirable effect. Eleven glass fiber samples and milled glass fiber were used to show these materials' effect on Iraqi cement with (0.125, 0.25, 0.5

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Publication Date
Tue Aug 15 2023
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of Developmental Leadership on Adaptive Performance- Analytical Research General Directorates of Education in Baghdad province
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The research aims to reveal the impact of developmental leadership in its dimensions (ideal model, interest in employees, inspiration and motivation) as an independent variable in achieving adaptive performance in its dimensions (Creative problem solving, learning and motivation, Training efforts, adaptability, work stress management, dealing with crises and emergencies) as a dependent variable, and the research aims to enhance the quality of developmental leadership in the research sample through this leadership style, which is a modern style and is still under research and study with a focus on the benefit of adaptive performance From a psychological and organizational research sample consisting of (106) respondents from the middle adm

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Publication Date
Sun Sep 15 2019
Journal Name
Al-academy
Characteristics of the Artistic Construction of Light and Color Focus in the Theater Performance: محمد عزيز حسن
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The theater has a living environment that resembles or realistically simulates the real life environment on the stage where we see the place, light and living being  as elements representing a picture of the life scene and for a period of time the theater merely conveyed that image, but with the development of the world industrially and technologically, the perception of this picture has evolved with the emergence of intellectual progress where  each part has advantages and  Philosophical goals that  are consistent with the evolution of form. The theatrical lighting, colors and landscapes have become parts in the composition of a new life component in form and content and based on the above this research is titled&nbs

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Publication Date
Mon Aug 01 2022
Journal Name
Optik
Assessing the optoelectronic performance of d-orbital doped cubic HfO2: The case of W, Nb, and Mo
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This contribution provides an atomistic understanding into the impact of W, Nb, and Mo co-substitution at Hf-site of cubic HfO2 lattice to produce Hf1−xTMxO2 system at x = 25%. The calculations have been performed under the framework of density functional theory supported by Habbured parameter (DFT+U). Structural analysis demonstrates that the recorded lattice constants is in good coherence with the previously published results. For the lattice parameters, contraction by 1.33% comparing with the host system has been reported. Furthermore, the doping effect of TM on the band gap leads to its reduction in the resulting Hf0.75TM0.25O2 configurations. The partial density of states (PDOS) indicate that hybridization through localized electroni

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Publication Date
Sat Jul 01 2023
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The role of e-learning standards in auditing in auditing the performance of customer capita: applied research
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                  In light of the corona pandemic, educational institutions have moved to learning and teaching via the Internet and e-learning ,and this is considered a turning  point in course of higher education in Iraq in particular and education in general, which generated a great challenge for educational institutions to achieve the highest possible levels in practices and processes to reach the highest quality of their outputs from graduate students to the labor market that auditing performance by adopting e-learning standards is one of the effective tools that help the management of educational institutions by providing information on the ex

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Publication Date
Mon Aug 01 2022
Journal Name
Optik
Assessing the optoelectronic performance of d-orbital doped cubic HfO2: The case of W, Nb, and Mo
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This contribution provides an atomistic understanding into the impact of W, Nb, and Mo co-substitution at Hf-site of cubic HfO2 lattice to produce Hf1−xTMxO2 system at x = 25%. The calculations have been performed under the framework of density functional theory supported by Habbured parameter (DFT+U). Structural analysis demonstrates that the recorded lattice constants is in good coherence with the previously published results. For the lattice parameters, contraction by 1.33% comparing with the host system has been reported. Furthermore, the doping effect of TM on the band gap leads to its reduction in the resulting Hf0.75TM0.25O2 configurations. The partial density of states (PDOS) indicate that hybridization through localized electroni

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Publication Date
Fri Jun 29 2018
Journal Name
Journal Of Engineering
Numerical Investigation of the Effect of Inserted Twisted Tape inside Submerged Bundle Tubes on its Thermal Performance
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Twisted tape insertion in the smooth plain tube is one of the types of passive methods that are used to enhance heat transfer. Swirl fluid flow inside the tube and related heat transfer characteristics are very complex. ANSYS FLUENT (V 16.1) and ASPEN industrial program are used in analyzing this technique for enhancement heat transfer. A circular plain tube has length L=8534mm and 17 mm inner diameter with a twisted tape of twist ratio of y = (H/D) = (150/17) =8.8 along the plain tube were considered for this study. Eight Reynolds numbers (Re) of 784, 1000, 2000, 3000, 4000, 5000, 6000 and 7000 are used to analyze the response of thermal performance. Crude oil API 28 exit temperature, film heat transfer coefficient, Nus

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Publication Date
Thu Dec 01 2016
Journal Name
Journal Of Engineering
Analytical and Experimental Investigation for the Effect of Air Injection Angle on the Performance of Airlift Pump
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The effect of air injection angle on the performance of airlift pump used for water pumping has been studied analytically and experimentally. An airlift pump of dimensions 42mm diameter and 2200 mm length with conventional and modified air injection device was considered. A modification on conventional injection device (normal air-jacket type) was carried out by changing injection angle from 90  (for conventional) to 45  and 22.5  (for modified). Continuity and one-dimensional momentum balance for the flow field with basic principle of two-phase flow and expressions of slip ratio and friction factor as function of flow rates were formulated. The analytical and experimental investigations were carried out f

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Publication Date
Thu Oct 03 2019
Journal Name
Mesopotamia Journal Of Agriculture
EFFECT OF ADDING DIFFERENT LEVELS OF OLEUROPEIN TO BROILERS DIETS ON PRODUCTION PERFORMANCE AND SOME PHYSIOLOGICAL TRAITS
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This study has been carried out in the Station of Poultry Researches which is affiliated to the General Office of Agricultural Researches / Ministry of Agriculture during the period from 25/02/2019 to 08/04/2019 (42)days .Five hundred unsexed one day old chick of type (Ross 308) used in this study, and has been fed on diets which oleuropeinin has been added to it with the levels 2,2.5,3 and3.5 g/kg as a feed for the treatments T2 , T3 , T4 and T5 respectively and compared to the control treatment T1 which is devoid of addition, every treatment included Four replicates each one has 25 birds in order to study the effect of adding a various levels of oleuropein into the diet on the production and physiological performance for broilers. The res

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Publication Date
Thu Jul 24 2014
Journal Name
Desalination And Water Treatment
Performance of granular dead anaerobic sludge as permeable reactive barrier for containment of lead from contaminated groundwater
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