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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
Mon Jun 05 2023
Journal Name
Journal Of Engineering
Experimental Evaluation of the Performance of One-Axis Daily Tracking and Fixed PV Module in Baghdad, Iraq
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An attempt was made to evaluate the PV performance of one-axis daily tracking and fixed system for Baghdad, Iraq. Two experimental simulations were conducted on a PV module for that purpose. Measurements included incident solar radiation, load voltage and load current. The first experiment was carried out for six months of winter half of year to simulate the one-axis daily tracking. The azimuth angle was due south while the tilt angle was being set to optimum according to each day of simulation. The second experiment was done at one day to simulate the PV module of fixed angles. It is found that there is a significant power gain of 29.6% for the tracking system in respect to the fixed one. The one-axis daily tracking was much more effect

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Publication Date
Thu Nov 21 2013
Journal Name
Pharmaceutical Development And Technology
Effect of ethylcellulose and propylene glycol on the controlled-release performance of glyceryl monooleate–mertronidazole periodontal gel
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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 Mar 01 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 smooth plain tube is one of types of passive methods that is used to enhance heat transfer. Swirl fluid flow inside 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 twisted tape has twist ratio of y = (H/D) = (150/17) =8.8 along with a 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, Nusselt number

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Publication Date
Wed Apr 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Dimensions of performance to provide nursing services: a comparative analytical research in Baghdad of Rusafa Health Organization
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     This research aims to study the performance of operations to provide nursing services, which included dimensions (quality, timeliness, leadership skills, behavioral manifestations, relationships with others, problem-solving and decision-making, job performance) and its effects in nursing performance. The research to prove the value of the performance of service delivery processes dimensions by nursing staffs working in Iraqi hospitals, nursing and measuring performance. To find out the nature of nursing services, and a comparison between hospitals to measure the extent of the application dimensional among themselves, and that by relying on the dimensions of a global study, which was measu

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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
Mon Apr 18 2022
Journal Name
Energies
Effect of Varying AgNO3 and CS(NH2)2 Concentrations on Performance of Ag2S/ZnO NRs/ITO Photoanode
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This research focuses on improving the photoelectrochemical performance of binary heterostructure Ag2S/ZnO NRs/ITO by manipulating synthesis conditions, particularly the concentrations of sliver nitrate AgNO3 and thiourea CS(NH2)2. The photoelectrochemical performance of Ag2S/ZnO nanorods on indium tin oxide (ITO) nanocomposite was compared to pristine ZnO NRs/ITO photoanode. The hydrothermal technique, an eco-friendly, low-cost method, was used to successfully produce Ag2S/ZnO NRs at different concentrations of AgNO3 and CS(NH2)2. The obtained thin films were characterized using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), ultraviolet-visible spectroscopy

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Publication Date
Mon Jan 04 2021
Journal Name
Geofluids
Performance Evaluation of Polyethersulfone Membranes for Competitive Removal of Cd2+, Co2+, and Pb2+ Ions from Simulated Groundwater
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This paper presents studying the performance of three types of polyethersulfone (PES) membrane for the simultaneous removal of Co2+ ions, Cd2+ ions, and Pb2+ ions from binary and ternary aqueous solutions. Co2+ ions, Cd2+ ions, and Pb2+ ions with two different initial concentrations (e.g., 10 and 50 ppm) were selected as examples of heavy metals that contaminate the groundwater as a result of geological and human activities. This study investigated the effect of types of PES membrane and metal ions concentration on the separation process. For the binary aqueous solutions, the permeation flux of the PES2 membranes was higher for the separation process of solutions containing 50 ppm of Cd2+ ions and 10 ppm of Co2+ ions (24.7 L

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Publication Date
Sun Mar 01 2026
Journal Name
Results In Engineering
Role of mineral filler type and ratio in the rheological, fatigue, and adhesive performance of asphalt mastics
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Mineral fillers are a fundamental component of asphalt mastic and play a critical role in governing the mechanical performance and durability of flexible pavements. Variations in filler type and dosage can substantially alter mastic stiffness, deformation resistance, fatigue behavior, and adhesion. The objective of this study is to systematically evaluate the influence of mineral filler type and filler-to-asphalt (F/A) ratio on the rheological, fatigue, and adhesive performance of asphalt mastics. Three commonly used fillers; limestone dust, Portland cement, and hydrated lime were investigated at four F/A ratios (0.6, 0.8, 1.0, and 1.2). A comprehensive experimental program was conducted, including conventional binder characterization, Mult

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Publication Date
Mon Mar 29 2021
Journal Name
Journal Of Engineering
Experimental Investigation of Thermal Performance of Aluminum Foil Coated with Polyester in a Direct Evaporative Cooling System
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An experimental study was carried out for an evaporative cooling system in order to investigate the effect of using an aluminum pad coated with fabric polyester. In the present work, it was considered to use a new different type of cooling medium and test its performance during the change in the wet-bulb temperature and dry-bulb temperature of the supply air outside of the pad, the relative humidity of the supply air, the amount of air supplied (300-600) CFM and also the change of the amount of circulated water (1.75, 2.5, 4.5) liter per minute. A decrease in the WBT of the air was obtained, whereas the WBT of the air entering the pad was 26.5 . In contrast, the WBT of the outside air had reached 23  even though eva

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