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Thermal Characteristics of Closed Wet Cooling Tower Using Different Heat Exchanger Tubes Arrangement
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This paper presents thermal characteristics analysis of a modified Closed Wet Cooling Tower (CWCT) based on heat and mass transfer principles to improve the performance of this tower in Iraq. A prototype of CWCT optimized by added packing was designed, manufactured and tested for cooling capacity of 9 kW. Experiments are conducted to explore the effects of various operational and conformational parameters on the thermal performance. In the test section, spray water temperature and both dry bulb temperature and relative humidity of the air measured at intermediate points of the heat exchanger and packing. Heat exchangers consist of four rows and eight columns for an inline tubes arrangement and six rows and five columns for staggered tubes arrangement. According to experimental data, the inline tubes arrangement has a better thermal performance than the staggered tubes arrangement. The inline tubes arrangement enhanced thermal efficiency more than (7%) compared to the staggered tubes arrangement. Furthermore the effect of added packing to CWCT on thermal performance was significant compared to CWCT without packing. Comparing CWCT with packing, it has been observed that the best performance for the CWCT with packing under heat exchanger. It can be watched that the thermal efficiency for CWCT with packing under heat exchanger and CWCT with packing above heat exchanger approximately (28%) and (16%) higher than that CWCT without packing respectively. This study provides correlations to predict heat and mass transfer considering the influences of operational parameters for both inline and staggered heat exchanger tubes arrangement.

 

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Publication Date
Sun Sep 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Quality Improvement of Spent Lubricating Oil
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The acidity of spent lubricant was treated using sodium hydroxide solution. The effect of three variables on the treatment have been studied . These are mixing time rangingfrom 5-35 minutes, NaOH to lubricant weight ratio ranging from  0.25-1.25 and weight percentage  of NaOH ranging from  2-6 % .

The experimental design of Box-Wilson method is adopted to find a useful relationship between the three controllable variables and the lowering in the acidity of the spent lubricant. Then the effective variables and interactions are identified using the statistical analysis(F-test) of  three variable fractional design. The mathematical model is well represented  by a second order polynomial.

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Fabrication of multi-junction solar cells
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Fabrication of solar cell prepared by thermal spray and vacuum thermal evaporation method on silicon wafer(n-type) and studying its efficiency. The film have been deposited on three layers(ZnO then CdS and CdTe) on Si and glass respectively.Direct energy gap was calculated and equal to (4.3,3.4,3)eV and indirect energy gap equal to (3.5,2.5,1.5)eV respectively . Efficiency was calculated for the cell of area 2cm2 it was equal to 0.14%.

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Publication Date
Thu Jul 01 2021
Journal Name
Iraqi Journal Of Science
Synthesis and Characterization of Cu2FeSnSe4 Nanofilms
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Well dispersed Cu2FeSnSe4 (CFTSe) nanofilms were synthesized by hot-injection method. The structural and morphological measurements were characterized using XRD (X-ray diffraction), Raman spectroscopy, SEM (scanning electron microscopy), and TEM (transmission electron microscopy). Chemical composition and optical properties of as-synthesized CFTSe nanoparticles were characterized using EDS (energy dispersive spectroscopy) and UV-Vis spectrophotometry. The average particle size of the nanoparticles was about 7-10 nm. The UV-Vis absorption spectra showed that the synthesized CFTS nanofilms have a band gap (Eg) of about 1.16 eV. Photo-electrochemical characteristics of CFTSe nanoparticles were studied and indicated their potential application

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Publication Date
Sun Jan 01 2023
Journal Name
Aip Conference Proceedings
Nano chitosan adsorption of o-Nitroaniline
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Publication Date
Sun Jun 07 2009
Journal Name
Baghdad Science Journal
New Formulas of Special Singular Matrices
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Many of the elementary transformations of determinants which are used in their evaluation and in the solution of linear equations may by expressed in the notation of matrices. In this paper, some new interesting formulas of special matrices are introduced and proved that the determinants of these special matrices have the values zero. All formulation has been coded in MATLAB 7.

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Publication Date
Wed Dec 14 2016
Journal Name
Journal Of Baghdad College Of Dentistry
Immunohistochemical Expression of Endocan in Ameloblastoma
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Background: Ameloblastoma is the most common clinically significant odontogenic tumor, known for its locally invasive potential and frequent recurrences unless treated radically. Endocan is a soluble proteoglycan which is reported to have prognostic implications in multiple human diseases and tumors. This study aims to describe the expression of endocan in ameloblastoma. Materials and methods: With immunoperoxidase method; tissue sections of formalin fixed- paraffin embedded blocks for ameloblastomas were stained with monoclonal antibodies to endocan, the localization of the endocan expression was examined and the resulting scores of the tissue sections were analyzed according to age, sex, site and tumor subtype. Results: endocan was found

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Publication Date
Sun Mar 07 2010
Journal Name
Baghdad Science Journal
Selection of highly ethanol productive yeast
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Seventy five isolates of Saccharomyces cerevisiae were identified, they were isolated from different local sources which included decayed fruits and vegetables, vinegar, fermented pasta, baker yeast and an alcohol factory. Identification of isolates was carried out by cultural microscopical and biochemical tests. Ethanol sensitivity of the isolates showed that the minimal inhibitory concentration of the isolate (Sy18) was 16% and Lethal concentration was 17%. The isolate (Sy18) was most efficient as ethanol producer 9.36% (v/w). The ideal conditions to produce ethanol from Date syrup by yeast isolate, were evaluated, various temperatures, pH, Brix, incubation period and different levels of (NH4)2HP04. Maximum ethanol produced was 10

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Publication Date
Sat Dec 01 2012
Journal Name
Advances In Bioresearch
Cytotoxicity of Miltefosine against Leishmania majorPromastigotes
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Publication Date
Fri Oct 11 2019
Journal Name
Journal Of The College Of Education For Women
The Symbolic Interaction of the Kindergarten
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The Symbolic Interaction of the Kindergarten

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Publication Date
Sun Mar 26 2023
Journal Name
Wasit Journal Of Pure Sciences
Pure Graph of a Commutative Ring
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A new definition of a graph called Pure graph of a ring denote Pur(R) was presented , where the vertices of the graph represent the elements of R such that there is an edge between the two vertices ???? and ???? if and only if ????=???????? ???????? ????=????????, denoted by pur(R) . In this work we studied some new properties of pur(R) finally we defined the complement of pur(R) and studied some of it is properties

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