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EFFECT OF COOLING RATE ON MECHANICAL PROPERTIES OF EUTECTIC AND HYPOEUTECTIC Al-Si ALLOYS
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In this research the effect of cooling rate and mold type on mechanical properties of the eutectic
and hypoeutectic (Al-Si) alloys has been studied. The alloys used in this research work were (Al- 12.6%Si
alloy) and (Al- 7%Si alloy).The two alloys have been melted and poured in two types of molds with
different cooling rates. One of them was a sand mold and the other was metal mold. Mechanical tests
(hardness, tensile test and impact test) were carried out on the specimens. Also the metallographic
examination was performed.
It has been found that the values of hardness for the alloys(Al-12.6%Si and Al-7%Si) which poured in
metal mold is greater than the values of hardness for the same alloy when it poured in a heated metal
mold at different temperatures or in sand mold. The strength and impact resistance for the alloys (Al-
12.6%Si and Al-7%Si) are greater when these were poured in a metal molds than that when it poured in a
sand mold.
Furthermore, the higher cooling rates enhance the strength, hardness and impact resistance for the
two alloys, while the low cooling rates reduces these mechanical properties.
The percentage of elongation and the amounts of formed porosity decreased when the cooling rates
increased

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Publication Date
Wed May 01 2024
Journal Name
Journal Of Physics: Conference Series
A study of the Electrical and Dialectical proprieties of S<sub>60-</sub>Se<sub>40-X</sub>-Pb<sub>X</sub>Chalcogenide Compound
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Abstract<p>In this study, the melting-cooling method was used to prepare the chalcogenide compound S<sub>60</sub>-Se<sub>40-X</sub>-Pb<sub>X</sub>. Four samples were obtained by partial replacement of Selenium with Lead in the weight ratios x = 0, 10, 20, and 30, respectively. The materials were mixed separately, ground, placed in quartz ampoules, and heated to 500 degrees Celsius. After conducting several operations on the samples, their insulating properties were studied, represented by the real dielectric constant and the imaginary dielectric constant, and the electrical conductivity was measured as a function of the frequency. It was found that partial replacement plays an impo</p> ... Show More
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Publication Date
Tue Sep 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
Evaluating the quality of educational services according to the modified Servqual modelStudy of a sample of students of the Faculty of Management and Economics / University of Baghdad
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The research aims to apply a modified SERVQUAL model to evaluate the quality of the educational services via conducting exploratory research for students from the College of Administration and Economics- Department of Business Administration- Evening studies at the University of Baghdad. Questionnaire of two parts was distributed to a sample of (72) students out of (720) students of the 2nd.,3rd. and 4th. year in the beginning of the second semester of the year 2008-2009 to measure the expectations and perceptions to the quality of the educational services. Five major dimensions were analyzed to see the gaps for (22) variables. The study concluded that there were (13) variables confirmed that the

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Publication Date
Mon Jun 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Theories of the structure of modern finance : practical application of pecking order theory and the life cycle of the company/analytical research of asmple of foreign companies
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 Is the subject of the financial structure of the most important topics for which she received the interests of scientific research in the field of financial management , as it emerged several theories about choosing a financial structure appropriate for the facility and behavior change funding them , and in spite of that there is no agreement on a specific theory answer various questions in this regard , and a special issue of the financial structure optimization.

The objective of the research was to identify the most important theories of the structure of modern financial theory has been to focus on the capture of financial firms in two different stages of their life cycle , so-called growth and ma

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Publication Date
Tue Nov 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Performance evaluation of policies and programs accordance with guide prepared by a dutch court of audit and the board of supreme audit (case study in wasit state company for textile industries)
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Abstract\

preparation process of performance evaluation in organizations is of extreme importance, and under development in organizations and the opening of markets and technological developments in the industry and heightened competition among industrial organizations imposed systems are built for performance give a clear picture about performance and competition,  And centered research problem in answering the following questions: Is performance evaluation system is available in Wasit State Company for Textile Industries(Research sample ), This research aims to assess the performance of policies and programs in the company, according to guide performance evaluation of programs and policies prepared by the Dutch Cou

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Publication Date
Thu Sep 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
Leadership ethics and transformational leadership to develop perceptions of organizational work supportA survey of a sample of the staff of the Ministry of Water Resources
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The aim of organizational contemporary is development man power active, in spit-of there are littlie resources. But in the Iraqi environment there are too much resources with performance inhabiting. specially in the ministry of water resources (sample of this research), about dryness and lower levels of rivers. There for this study have some important variable, it is ethical leadership & transformational leadership as (independent variable), and Perceived organizational support(dependent variable). Over here to invest with authority on the problem of research, is weakness harmony between employed perception and the pattern of leadership. We find decline in of reaction of organ compound between the variable to weaken high perf

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Publication Date
Sat Feb 01 2020
Journal Name
Journal Of Economics And Administrative Sciences
The impact of social audit in social performance an applied study of the views of a sample of managers and staff of Algerian business organizations
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            This research aims at clarifying the concept of social auditing, which is one of the most important reasons for its emergence is social responsibility accounting and its role in measuring the social performance of enterprises. The study also aimed to know how social auditing has an impact and its role in improving the social performance of business organizations, and the research refers to testing the hypotheses of an impact of social auditing on social performance through a commitment to social responsibility. The research sample consisted of 200 individuals from 20 Algerian business organizations and represented individuals who were researched in managers and em

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Publication Date
Tue Jan 01 2013
Journal Name
Innovative Systems Design And Engineering
Water And Alcohol Extraction Of Thyme Plant (Thymus Vulgaris) And Activity Study Against Bacteria, Tumors And Used As Anti-Oxidant In Margarine Manufacture
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Isolation had been done for active substances from Thyme plant (Thymus Vulgaris) such as volatile oils, Saponins and Tannins. The percentage in form was (21.1%),(59.2%),( 9.7%) respectively. Also a study of anti-bacterial activity of extracts from Thyme using two types of pathogenic bacteria Escherichia Coli and aurous Staphylococcus showed the ability of inhibition for all different extracts by vary inhibition diameters for different active substances, concentrations and bacteria. One type of cancer cellular line used to study the effect of Thyme extracts on the growth of cells in the laboratory and thus know the specifications of extracts as anti-tumor, (L20B) cell line have been used which is mice Transformed cell Line. The possibility o

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Publication Date
Thu Jan 01 2015
Journal Name
Diyala Journal For Pure Science
Synthesis and Spectroscopic Study of New Bidentate Schiff Base type (NN) and it’s Complexes with MnII, FeII, CoII, NiII, CuII and CdII Ions .
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four coordinated complexes for divalent metal ions : Mn, Fe, Co, Ni, Cu and Cd have been synthesized using bidentate Schiff base ligand type (NN)formed by the condensation of o-phenylenediamine , p- methylbenzadehyde and furfural in methanol. The ligand was reacted with divalent metal chloride forming complexes of the types :[M(L)Cl2] where : MII=Mn, Fe, Ni, Cu, and Cd . These new compounds were characterized by elemental analysis, spectroscopic methods (FT-IR, U.V-Vis, 1HNMR (for ligand only and atomic absorption) , magnetic susceptibility, chloride content along with conductivity measurement. These studies revealed that the geometry for all complexes about central metal ion is tetrahedral.

Publication Date
Thu May 14 2009
Journal Name
Journal Of Kerbala University
Synthesis and Characterization of Novel Macrocyclic ligand and its complexes with (Co(II) ,Ni(II) ,Cu(II) ,Zn(II) , and Cd(II) ) ions.
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A new Macrocyclic Schiff base ligand Bis[4-hydroxy(1,2-ethylene-dioxidebenzylidene) pheylenediamine] [H2L] and its complexes with (Co(II) , Ni(II) , Cu(II) , Zn(II) and Cd(II)) are reported . The ligand was prepared in two steps,in the first step a solution of (o-phenylene diamine) in methanol react under reflux with (2,4-dihydroxybenzylaldeyed) to give an (intermediatecompound) [Bis-1,2 (2,4-dihydroxybenzylediene)pheylinediamine] which react in the second step with (1,2- dichloro ethane) giving the mentioned ligand.Then the complexes were synthesis of adding of corresponding metal salts to the solution of the ligand in methanol under reflux with 1:1 metal to ligand ratio. On the basis of, molar conductance, I.R., UV-Vis, chloride content a

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Publication Date
Thu Mar 03 2022
Journal Name
V. International Scientific Congress Of Pure, Applied And Technological Science (minar Congress)
synthesis and characterization of new Co(II), Zn(II) and Cd(II) complexes derived from oxadiazole ligand and 1,10-phenanthroline as co-ligand
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In this work, prepared new ligand namely 5-(2,4-dichloro-phenyl)-1,3,4-oxadiazole-2-(3H)-thion, was obtained from the 2,4-dichlorobenzoyl chloride with hydrazine, after that reaxtion with CS2/KOH in methanol.