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Thermal and flow performance analysis of a concentrated linear Fresnel solar collector with transverse ribs
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This article deals with the impact of including transverse ribs within the absorber tube of the concentrated linear Fresnel collector (CLFRC) system with a secondary compound parabolic collector (CPC) on thermal and flow performance coefficients. The enhancement rates of heat transfer due to varying governing parameters were compared and analyzed parametrically at Reynolds numbers in the range 5,000–13,000, employing water as the heat transfer fluid. Simulations were performed to solve the governing equations using the finite volume method (FVM) under various boundary conditions. For all Reynolds numbers, the average Nusselt number in the circular tube in the CLFRC system with ribs was found to be larger than that of the plain absorber tube. Also, the inclusion of transverse ribs inside the absorber tube increases the average Nusselt number by approximately 115% at Re = 5,000 and 175% at Re = 13,000. For all Reynolds numbers, the skin friction coefficient of the circular tube with ribs in the CLFRC system is larger than that of the plain absorber tube. The coefficient of surface friction reduces as the Reynolds number increases. The performance assessment criterion was found to vary between 1.8 and 1.9 as the Reynolds number increases.

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Publication Date
Sun May 01 2022
Journal Name
Civil Engineering Journal
Phases of Urban Development Impact on the Assessment of Thermal Comfort: A Comparative Environmental Study
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Millions of pilgrims and visitors from numerous parts of the world flock to Karbala (one of the most prominent ideological and religious places in central Iraq) each year to visit the holy shrines in Karbala due to their sanctity. Many improvements have been made to the Two Holy Shrines (THS), the Shrines of Imam Husayn and Imam Abbas, and the area between them (ATHS), due to the high temperatures in this region and to improve pedestrian thermal comfort. Studies on improving outdoor thermal comfort in Karbala are scarce. Hence, this research aims to look into historical and current architectural changes and how they affect thermal comfort. On the hottest summer day, the ENVI-met software program was used to simulate the building des

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Publication Date
Wed Mar 18 2020
Journal Name
Baghdad Science Journal
Spectrophotometric and Reverse Flow Injection Method Determination of Nitrazepam in Pharmaceuticals Using O-Coumaric Acid as a New Chromogenic Reagent
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            A spectrophotometric- reverse flow injection analysis (rFIA) method has been proposed for the   determination of Nitrazepam (NIT) in pure and pharmaceutical preparations. The method is based upon the coupling reaction of NIT with a new reagent O-Coumaric acid (OCA) in the presence of sodium periodate in an aqueous solution. The blue color product was measured at 632 nm. The variation (chemical and physical parameters) related with reverse flow system were estimated. The linearity was over the range 15 - 450 µg/mL of NIT with detection limits and limit of quantification of 3.425 and 11.417 µg mL-1 NIT,respectively. The sample throughput of 28 samples

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Publication Date
Tue Jan 01 2019
Journal Name
Desalination And Water Treatment
Effect of synthesis parameters on the formation 4A zeolite crystals: characterization analysis and heavy metals uptake performance study for water treatment
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Publication Date
Mon Apr 06 2020
Journal Name
Asian Journal Of Civil Engineering
Integrated project delivery (IPD) method with BIM to improve the project performance: a case study in the Republic of Iraq
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Publication Date
Sun Sep 06 2015
Journal Name
Baghdad Science Journal
Oscillations of Third Order Half Linear Neutral Differential Equations
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In this paper the oscillation criterion was investigated for all solutions of the third-order half linear neutral differential equations. Some necessary and sufficient conditions are established for every solution of (a(t)[(x(t)±p(t)x(?(t) ) )^'' ]^? )^'+q(t) x^? (?(t) )=0, t?t_0, to be oscillatory. Examples are given to illustrate our main results.

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Publication Date
Thu Dec 31 2015
Journal Name
Al-khwarizmi Engineering Journal
Experimental Study on the Effect of Insertion of Copper Lessing Rings in Phase Change Material (PCM) on the Performance of Thermal Energy Storage Unit
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Abstract

One of the most suitable materials to be used in latent heat thermal energy storage system (LHTES) are Phase change materials, but a problem of slow melting and solidification processes made many researchers focusing on how to improve their thermal properties. This experimental work concerned with the enhancing of thermal conductivity of phase change material. The enhancing method was by the addition of copper Lessing rings in phase change material (paraffin wax). The effect of diameter for the used rings was studied by using two different diameters (0.5 cm and 1cm). Also, three volumetric percentages of rings addition (3%, 6% and 10%) were tested for each diameter. The discharging process was done with

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Publication Date
Sun Dec 05 2010
Journal Name
Baghdad Science Journal
Preparation and Study Hardness and Thermal Conductivity (Tc) to Polyester Resin Composite with (Titanium Dioxide, Zinc Oxide, Acrylonitril, Wood Flour Coconut
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This study is attempt to improve thermal isolation through measuring thermal conductivity composite of on polyester resin with fillers of (TiO2, ZnO, Acrylonitril, wood flour Coconut (Wf). The grain size of the fillers is 200 µm. The number of samples is (16) in addition to the virgin sample; these samples are prepared by cast molding method for polyester with filler volume fractions (5%, 10%, 15% and 20%). Shore hardness tests were used to measure the hardness and Lee disk method for thermal conductivity. The experimental results showed that the (20% ZnO) sample has the maximum value of thermal conductivity where (20% w.f) has minimum thermal conductivity .on the other hand (15% ZnO) sample give the maximum value of hardness where (20% w

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Publication Date
Wed May 18 2016
Journal Name
Al-academy
Stereotactic and its association with cognitive performance career: صلاح نوري محمود - ظبية محمد
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The importance of this study of the growing importance of perception of touch and its association with the job performance of industrial product since the perception stereotactic means he means practiced by the individual through job performance and has assets of knowledge in the mind of the user and require him to mind the capabilities and knowledge cognitive following their individual focus Zhennea.oanfalh following their enthusiasm when using Sense of touch. The study in the first chapter of the research problem to reveal the role played by the process of cognition and its relationship with the touch function of the industrial product and the associated defect in performance and harder to use. The study also pointed to the research ob

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Publication Date
Sat Feb 01 2020
Journal Name
Energy Reports
Study of photoemission and electronic properties of dye-sensitized solar cells
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We have investigated the photoemission and electronic properties at the PTCDI molecules interface on TiO2 and ZnO semiconductor by means of charge transition. A simple donor acceptor scenario used to calculate the rate for electron transfer of delocalized electronics in a non-degenerately TiO2 and ZnO electrodes to redox localized acceptors in an electrolytic. The dependent of electronic transition rate on the potential at contact of PTCDI with TiO2 and ZnO semiconductors, it has been discussion using TiO2 and ZnO electrodes in aqueous solutions. The charge transfer rate is determining by the overlapping electronic coupling to the TiO2 and ZnO electrodes, the transition energy, potential and polarity media within the theoretical scenario of

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Publication Date
Wed Aug 19 2020
Journal Name
International Journal Of Research In Social Sciences And Humanities
HUMOUR IN THE AMERICAN AND BRITISH COMEDYEPISODES: A DISCOURSE ANALYSIS STUDY
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DBNRAAK Mohammed, International Journal of Research in Social Sciences and Humanities, 2020

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