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Study of Energy Gains by Orientation of Solar Collectors in Baghdad City
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Firstly, in this study, a brief updated description and applications of different solar collectors used in renewable energy systems for supplying electric and thermal energy was presented. Secondly, an attempt was made to utilize tilting orientation of solar collector for maximizing collector energy with time in respect to horizontal orientation. For energy calculation, global solar radiation was used since they are directly related.  For that purpose, field measurements of half-hourly radiation on two flat panels of tilting and horizontal orientations were carried out throughout 8-month period under local climate of Baghdad. Then, energy gain and radiation level averages were calculated based on the field radiation data using Excel programming. The tilting orientation was found to be more effective for the winter months with significant energy gains of larger than 40% and maximum gain of 58%. On the contrary, the radiation levels on collector were lower during winter months. Finally, for clear sky condition, the average solar radiations for tilting and horizontal orientations of collector were of 910 W/m2 and 713 W/m2 respectively.

 

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Publication Date
Mon Feb 13 2023
Journal Name
Journal Of Educational And Psychological Researches
The Level of Mental Alertness and Its Relationship to Academic Self-Efficacy among Northern Border University Students
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Abstract

This study aims at investigating the relationship between mindfulness and academic self-efficacy among Northern Border University students. To achieve this objective, the researcher adopted the correlative survey method for (97) students. For data collection, the researcher developed a mindfulness scale consisting of (42) items divided into seven topics, each one consisting of six items. The researcher developed an academic self-efficacy scale consisting of (20) items, adopting a five-point Likert scale. The results showed that there is a high level of mindfulness among students at the level of the seven units which formed the mindfulness scale; the conscious thinking unit showed the highest mean value o

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Publication Date
Fri Apr 01 2016
Journal Name
Journal Of Engineering
Separation of Lead (Pb2+) and Cadmium (Cd2+) from Single and Binary Salt Aqueous Solutions Using Nanofiltration Membranes
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The present work reports on the performance of three types of nanofiltration membranes in the removal of highly polluting and toxic lead (Pb2+) and cadmium (Cd2+) from single and binary salt aqueous solutions simulating real wastewaters. The effect of the operating variables (pH (5.5-6.5), types of NF membrane and initial ions concentration (10-250 ppm)) on the separation process and water flux was investigated. It was observed that the rejection efficiency increased with increasing pH of solution and decreasing the initial metal ions concentrations. While the flux decreased with increasing pH of solution and increasing initial metal ions concentrations. The maximum rejection of lead and cadmium ion

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Publication Date
Thu Oct 29 2020
Journal Name
Complexity
Training and Testing Data Division Influence on Hybrid Machine Learning Model Process: Application of River Flow Forecasting
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The hydrological process has a dynamic nature characterised by randomness and complex phenomena. The application of machine learning (ML) models in forecasting river flow has grown rapidly. This is owing to their capacity to simulate the complex phenomena associated with hydrological and environmental processes. Four different ML models were developed for river flow forecasting located in semiarid region, Iraq. The effectiveness of data division influence on the ML models process was investigated. Three data division modeling scenarios were inspected including 70%–30%, 80%–20, and 90%–10%. Several statistical indicators are computed to verify the performance of the models. The results revealed the potential of the hybridized s

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Publication Date
Sat Jan 01 2022
Journal Name
Desalination And Water Treatment
Preparation and application of polyethersulfone ultrafiltration membrane incorporating NaX zeolite for lead ions removal from aqueous solutions
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Publication Date
Fri Mar 15 2019
Journal Name
Al-khwarizmi Engineering Journal
Effect Use of Two Chemical Compounds Sodium Nitrate and Sodium Silicate as Corrosion Inhibitor to Steel Reinforcement
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Corrosion of steel reinforcement is one of the biggest problems facing all countries in the world like bridges in the beach area and marine constructions which lead to study these problems and apply some economical solutions. According to the high cost of repair for these constructions, were studied the effect of using kind of chemical compounds sodium nitrite(NaNO2) and sodium silicate(Na2SiO3) as corrosion inhibitors admixture for steel bars that immersed partially in electrolyte solution (water + sodium chloride in 3% conc.) (Approximately similar to the concentration of salt in sea water). The two inhibitors above added each one to the electrolyte solution at concentrations (0.5%, 1% and 2%) for both

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Publication Date
Mon Nov 27 2023
Journal Name
Korean Journal Of Orthodontics
Effectiveness of laser-engineered copper-nickel titanium versus superelastic nickel-titanium aligning archwires: A randomized clinical trial
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Publication Date
Sun Jun 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
Estimate the Best production function of the General Company for Iraqi Cement for the period (1996-2010)
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     The General Company for Iraqi Cement is regarded as one of the companies that contribute to support the Iraqi economy. It contributes to provide the material of cement which fulfils the consumer and investment need in the markets in competitive prices and not to resort to the importing of the cement from abroad. That would save a great share of the purchase parity of the poor sectors of society. The estimation  of production function will contribute to putting the company.

The application functions of  the standard production of  benefit critical to clarify the actual relationship between production & its components, & allow to clarify the i

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Publication Date
Wed Jan 01 2020
Journal Name
Dar Amjad For Publishing And Distribution, The Hashemite Kingdom Of Jordan
Statistical methods for calculating the validity and reliability of tests and measures using IBM SPSS Statistics Version24
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لقد كان حرص المؤلف على إصدار هذا الكتاب نابعا ً من قناعة تامة بأن مجال التقويم والقياس بحاجة إلى كتاب علمي حديث يتناول عرض أدوات الاختبار والقياس والمتمثلة بالصدق والثبات ويتسم بالوضوح في التعبير عن المفاهيم والمصطلحات والأنواع لكل منها ليكون وسيلة مبسطة بأيدي الأساتذة والباحثين وطلبتي الدراسات العليا الماجستير والدكتوراه لإستخراج صدق وثبات الاختبارات والمقاييس بطرق إحصائية متقدمة من خلال إستخدام البرنا

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Publication Date
Sun Mar 02 2008
Journal Name
Baghdad Science Journal
The synergistic effect of borax and chlorinated paraffin as flame – retardants for epoxy and unsaturated polyester resins
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In this investigation , borax (B) (additive I) and chlorinated paraffin (CP.) (additive II) ,were used as flame retardants for each of epoxy and unsaturated polyester resins in the weight ratios of 2,4,6, & 8% by preparing films of (130×130×3) mm dimensions. Also films of these resins with a mixture of [50%(B.)+50%(CP.)] (additive III) in the same weight ratios were prepared in order to study the synergistic effect of these additives on the flammability of the two resins . Three standard test methods were used to measure the flame retardation which are : 1-ASTM : D-2863 2-ASTM : D-635 3-ASTM : D-3014

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Publication Date
Fri Jul 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Comparison some of methods wavelet estimation for non parametric regression function with missing response variable at random
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Abstract

 The problem of missing data represents a major obstacle before researchers in the process of data analysis in different fields since , this problem is a recurrent one in all fields of study including social , medical , astronomical and clinical experiments .

The presence of such a problem within the data to be studied may influence negatively on the analysis and it may lead to misleading conclusions , together with the fact that these conclusions that result from a great bias caused by that problem in spite of the efficiency of wavelet methods but they are also affected by the missing of data , in addition to the impact of the problem of miss of accuracy estimation

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