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joe-1593
Mechanical Integrity of Printed Circuit Heat Exchanger
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The printed circuit heat exchanger is a plate type heat exchanger with a high performance and compact size. Heat exchangers such as this need a unique form of bonding and other techniques to be used in their construction. In this study, the process of joining plates, diffusion bonding, was performed and studied. A special furnace was manufactured for bonding purposes. The bonding process of copper metal was carried out under specific conditions of a high temperature up to 700 oC, high pressure of 3.45 MPa, and in an inert environment (Argon gas) to make tensile samples. The tensile samples are cylindrical shapes containing groves representing the flow channels in the printed circuit heat exchanger and checking their tensile strength in addition to the standard shape of the tensile specimen to check the yield and ultimate strength of the copper. A higher tensile strength was obtained for diffusion bonded specimens than the yield strength of copper, up to 1.35 times the copper yield strength. The tensile strength decreases with the increase in the number of groves and the decrease in the distance between one grove and another. This is because the stress is concentrated in the sharp corners. A prototype heat exchanger of two plates and a header to be tested for its compressive strength was also manufactured. The results showed that the bond bears an air pressure of up to 8 bar without fail. It was also found to withstand a hydraulic pressure of up to 60 bar until it reached failure.

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Publication Date
Sun Jun 06 2010
Journal Name
Baghdad Science Journal
Effect of Chromium on Growth of green ALGA SCENEDESMUS QUADR ICAUDA (TURP.) DE BERB. With increase of nitrogen concentration
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The study was conducted to identify the toxicity of chromium on scenedesmus quadricauda algae alone and in the presence of nutrient metal (Nitrogen). Different concentrations of chromium (0.5, 1.5 , 2.5, 3.5 , 4.5mg/L) were used and the presence nitrogen is (5 ,10 ,50 ,100mg/L) on cultur media(chu-10) with used for cultivation of the algae in controlled conditions(25oC , light intensity 380 –?E/m2 /s. The results showed increasing in the toxicity of the metal when is alone , excess of concentrations an time of exposure. The growth rate decreased from 0.44 to 0.06 cell/ hour after 12 day of the biging of the experiment and of concentrate 4.5 mg/L of chromium. The intermediate active concentrations of the chromium(EC50) was increase

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Publication Date
Sat Jul 01 2023
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The impact of the practice of professional doubt on the quality of the auditor's performance in Iraq: بحث استطلاعي
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              Due to the increasing interest in the quality of auditing by writers, researchers and regulators of the auditing profession. The matter necessitated a statement of the extent to which the auditor practices professional skepticism, because of its significant impact in discovering errors and material misrepresentations contained in the financial statements in order to give the financial community confidence in them and the success of the audit process. The research aims to clarify the concept and importance of the practice of professional skepticism and its effect on the quality of the auditor's performance in Iraq. To achieve the research objectives, the two re

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Publication Date
Fri Jan 01 2010
Journal Name
Bn Al-haitham Journal For Pure And Applied Sciences
Effects of Different Levels of Urea and Superphosphate Fertilizer in Some Growth Characters and the Yield of Fenugreek plant
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جريت التجربة في اصص فخارية سعة كل اصيص 4 كغم تربة في البيت الزجاجي التابع لقسم علوم الحياة/كلية التربية ابن الهيثـــــــــم/جـامعــة بـغداد لموســم النمـو 2008-2009 لدراســة تأثيــر اربعـــة مستويـــــات من سمــــاد اليوريـــا وهي (0, 0.1, 0.2, 0.4) غم/اصيص والتي تعادل (0, 100, 200, 400) كغم/هكتار وثلاث مستويات من سماد السوبر فوسفات وهي (0, 0.1, 0.2) غم/اصيص والتي تعادل (0, 100, 200) كغم/هكتارفي مكونـات الحاصـــل لنبــات الحلبـــة Trigonella foe

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Publication Date
Mon Jul 24 2023
Journal Name
Pollution Research
THERMODYNAMIC AND KINETIC STUDY OF ADSORPTION OF THE AZO DYE FROM AQUEOUS SOLUTION ON THE SURFACE OF IRAQI FLINT
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Publication Date
Thu Dec 28 2023
Journal Name
Journal Of Physical Education
Evaluating the academic achievement of graduate students working in the field of physical education from their point of view
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The research aimed to prepare a measure to evaluate the academic achievement of graduates working in the field of physical education from their point of view, to identify the extent to which graduating students benefit from the curriculum of the College of Physical Education and Sports Sciences, University of Baghdad/Al-Jadriya, and to identify the impact of academic subjects in the practical and theoretical fields. The researchers used the descriptive approach in the research procedures as it is an appropriate approach in achieving the research objectives. The following questions are: What are the academic subjects that have the most impact on graduating students? What are the academic subjects that have the least impact on the are

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Publication Date
Sun Jun 05 2011
Journal Name
Baghdad Science Journal
Some Probability Characteristics Functions of the Solution of a Stochastic Non-Linear Fredholm Integral Equation of the Second Kind
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In this research, some probability characteristics functions (probability density, characteristic, correlation and spectral density) are derived depending upon the smallest variance of the exact solution of supposing stochastic non-linear Fredholm integral equation of the second kind found by Adomian decomposition method (A.D.M)

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Publication Date
Tue Dec 13 2011
Journal Name
Iraqi Journal Of Laser
The Effect of 532nm Nd: YAG Pulsed Laser on the Activity of Superoxide dismutase and Alcoholdehydrogenase of Saccharomyces Cerevisiae
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In this study, the effect of Nd: YAG laser on the activity of superoxide dismutase (SOD) and alcoholdehydrogenase (ADH) was investigated. The Saccharomyces cells were irradiated using 532nm Q-Switched Nd: YAG laser with (1Hz) frequency. Different fluences 11.3, 22.6 and 33.9mJ/cm2 and different number of pulses 15, 30 and 60 pulse were used. The irradiated cells were incubated in a liquid nutritive medium for 24 hours. After incubation, the cells were harvested and disrupted to extract the intracellular enzymes and their activities were assessed. In comparison with the control, the irradiated cells showed a significant increase in the activity and the specific activity of SOD at energy densities of 11.3 and 22.6mJ/cm2 at 30 and 60 pulses

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Publication Date
Wed Jun 14 2023
Journal Name
Al-academy
The effectiveness of the harvesting strategy in the collection of environmental art by the Institute of Fine Arts students
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 The current research aims to: (know the effectiveness of the harvesting strategy in the achievement of the students of the Institute of Fine Arts in environmental art.
- In order to know this effectiveness, the researcher put a main zero hypothesis and derived six sub-hypotheses from it. the usual way; As the research community reached (120) male and female students of the Fine Arts Institutes for the morning study in Baghdad. As for the research sample, it was chosen by the simple random method, and the number was (75) male and female students for the year 2021-2022 AD. The researcher applied a pre-knowledge test for the four groups of research to find out the level of previous experiences of students in the subject of environmen

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Publication Date
Tue Sep 05 2023
Journal Name
Migration Letters
The Impact of Climate Change on the Increase in the Frequency of Drought in the Eastern Region of Iraq
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Aim: This abstract aims to highlight the critical nature of climate change as a pressing challenge facing humanity in the 21st century. It underscores the severe consequences it poses to essential facets of human existence, including water and energy resources, agricultural production, and the broader environmental systems. Method: The abstract primarily utilizes a descriptive approach to emphasize the impact of climate change on the Middle East, particularly the Arab region. It relies on a review of existing knowledge and data related to climate change and its effects on ecosystems and drought patterns. Results: The abstract outlines the direct and indirect repercussions of climate change on human life and the environment. It draws atten

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Publication Date
Sat Feb 01 2020
Journal Name
Journal Of Economics And Administrative Sciences
Study Impact of Some Factors on Daily Number of Hours Providing of Electricity in Baghdad City Using Path Analysis
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دُرِست العوامل المؤثرة في عدد ساعات تجهيز الكهرباء في مدينة بغداد، وتكونت عينة الدراسة من (365) مشاهدة يومية لعام 2018، وتمثلت بستة متغيرات استعملت في الدراسة. كان الهدف الرئيس هو دراسة العلاقة بين هذه المتغيرات، وتقدير تأثيرات المتغيرات التنبؤية في المتغير التابع (عدد ساعات تجهيز الكهرباء في مدينة بغداد). ولتحقيق ذلك استعملت نمذجة المعادلات الهيكلية/ تحليل المسار وبرنامج AMOS

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