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Experimental Study on the Effect of Using Metallic Brushes on the Charging and Discharging Time of Thermal Energy Storage Unit
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Phase change materials are known to be good in use in latent heat thermal energy storage (LHTES) systems, but one of their drawbacks is the slow melting and solidification processes. So that, in this work, enhancing heat transfer of phase change material is studied experimentally for in charging and discharging processes by the addition of high thermal conductive material such as copper in the form of brushes, which were added in both PCM and air sides. The additions of brushes have been carried out with different void fractions (97%, 94% and 90%) and the effect of four different air velocities was tested. The results indicate that the minimum brush void fraction gave the maximum heat transfer in PCM and reduced the time for melting for (ϵ=90%) up to 4.49 times as compare with the case of no brush. It can be seen that the addition of brushes in air side helped to reduce the solidification time and increase the convection heat transfer coefficient as the brush void fraction decreased. Also the minimum velocity (v = 1 m/s) gave maximum outlet temperature.

 

 

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Publication Date
Sat Apr 01 2023
Journal Name
Journal Of Legal, Ethical And Regulatory Issues
THE IMPACT OF THE ROLE OF THE ORTHODOX CHURCH ON THE POLITICS OF THE RUSSIAN FEDERATION
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The research tackles the nature of relationship between the Orthodox Church and the state in the Russian Federation. At the beginning of the nineties of the last century, the church had been performed a different role in its relationship with the state, and it had an effect over the internal and foreign policies for the Russian Federation. In political history of Russia, the church’s existence became an evident too much in comparing with the previous historical period, starting with the educational and political system, whether through a symbolic participating roles as what happened in the inauguration ceremony to take over responsibility of the head of state or taking actual roles such as influencing on the process of holding elections d

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Publication Date
Sat Dec 31 2016
Journal Name
مجلة جامعة االنبار للعلوم البدنية والرياضية
The effects of Pilates exercises while using the ladder barrel device on fitness and coordinatedin performance for motor formations in artistic gymnastics for students
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The aim of the research was to prepare Pilates exercises using the barrel ladder apparatus and to identify the effect of Pilates exercises on agility, coordination, and motor sequences of third-year female students in artistic gymnastics. The researcher adopted the experimental method to achieve the objectives of the study and to verify its hypotheses, as it is suitable for the nature and problem of the research. In selecting the research population, the researcher carefully chose the sample using a purposive method, clarifying its elements and constituent units. The research population consisted of third-year female students at the College of Physical Education and Sports Sciences for Women / University of Baghdad, with a total of 20 stud

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Publication Date
Wed Jul 31 2019
Journal Name
Journal Of Educational And Psychological Researches
An Instructional Design According to the constructivism Model for Chemistry Subject and Its Effect on the Life Skill by the Second Intermediate Female Students
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The research aims to identify the effect of teaching-learning design based on the constructivism theory on the life skills of middle stage students. The sample consisted of (60) students from one of the middle schools in Baghdad's governorate. The experimental group and control group consisted of 30 students for each group, the research tool was the life skills scale composed of (78) items. The scale proved its validity and reliability, which was found to be (0.85). The results showed a statistically significant difference in life skills between the two groups of research in favor of the experimental group, which studied the educational design according to models of constructivism theory compared to the usual method of teaching.

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Publication Date
Thu Oct 12 1995
Journal Name
International Journal Of Environmental Studies
ON THE SPATIAL AND SEASONAL VARIATIONS OF HEAVY METALS OF THE RAZZAZAH LAKE, IRAQ
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Five heavy metals, namely Cd, Cu, Fe, Mn, and Pb in the surface water and through the water column were studied at 10 selected stations in the Razzazah lake and Karbala drainage canal for the period between November 1990 to October 1991*. pH and total hardness were also measured. Lead was found to be the highest in concentration as overall average values, followed by an manganese, iron, copper then cadmium at the surface as well as along the water column. All the studied metals were below or close to the maximum allowed limits of Iraqi standards for inland water. The spatial and seasonal variations were discussed.

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Publication Date
Tue Dec 01 2020
Journal Name
Journal Of Engineering Science And Technology
THE INFLUENCE OF CHEMICAL COMPOSITION OF ASPHALT CEMENT ON THE PHYSICAL AND RHEOLOGICAL PROPERTIES
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Failure in asphalt mixture and distress in pavement are major issues to roads infrastructure. Selecting an appropriate chemical composition of asphalt cement is a key component in avoiding these issues. This work aimed to investigate the effect of the chemical composition of different polar fractions on the rheological and physical properties of asphalt cement. Four types of asphalt cement with penetration grades of 20/30, 40/50, 60/70 and 85/100 were divided into four fractions. Complex shear modules, rutting resistance and rotational viscosity of the asphalt cement were determined by using a Dynamic Shear Rheometer and a Rotation Viscometer, respectively. The results show that an increase in the asphaltene content and Gastel index resulte

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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
The influence of temperature and size on the absorption coefficient of CdSe quantum dots
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Abstract<p>Because of Cadmium selenide quantum dots (CdSe quantum dots) has a tuning energy gap in the visible light range, therefore; it is provided a simple theoretical model for the absorption coefficient of CdSe quantum dots, where the absorption coefficient determines the extent to which the light of a material can penetrate a specific wavelength before it is absorbed. CdSe quantum dots have an energy gap can be controlled through two effects: the temperature and the dot size of them. It is found that; there is an absorption threshold for each directed wavelength, where CdSe quantum dots begin to absorb the visible spectrum at a size of 1.4 nm at room temperature for a directed wavelength 3</p> ... Show More
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Publication Date
Tue Jan 10 2012
Journal Name
Iraqi Journal Of Science
THE IMPACT OF DISEASE AND HARVESTING ON THE DYNAMICAL BEHAVIOR OF PREY PREDATOR MODEL
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In this paper, a harvested prey-predator model involving infectious disease in prey is considered. The existence, uniqueness and boundedness of the solution are discussed. The stability analysis of all possible equilibrium points are carried out. The persistence conditions of the system are established. The behavior of the system is simulated and bifurcation diagrams are obtained for different parameters. The results show that the existence of disease and harvesting can give rise to multiple attractors, including chaos, with variations in critical parameters.

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Publication Date
Thu Sep 07 2023
Journal Name
Journal Of Higher Education Theory And Practice
THE CONCEPTUAL FRAMEWORK OF THE CULTURE OF PEACE AND ITS IMPLICATIONS ON SUSTAINABLE DEVELOPMENT
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The issue of peace, renunciation of violence, and acceptance of the other is one of the vital issues that rose to the top of the list of priorities at the end of the last century and the beginning of the new millennium of the conscience of the Iraqi people by spreading the culture of peace. In this context, we seek during this research to identify the concept of the culture of peace and its impact on sustainable development, and to draw a set of results and suggestions to consolidate this culture in our Iraqi society as an obligation of sustainable development.

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Publication Date
Thu Feb 05 2026
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of thermocycling on microleakage analysis of bulk filled base composite in comparison to incrementally placed nanohybrid composite in class II MOD restorations (An in vitro study)
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Background: The study aim was to evaluate thermocycling effect on microleakage of occlusal and cervical margins of MOD cavity filled with bulk filled composites in comparison to incrementally placed nanohybrid composite and to evaluate the difference in microleakage between enamel and dentin margins for the three materials groups. Materials and method: Forty eight maxillary first premolars were prepared with MOD cavities. Samples were divided into three groups of sixteen teeth according to material used: Grandio: Grandio. SDR: SDR +Grandio. X-tra: X-tra base + Grandio. Each group was subdivided into two according to be thermocycled or not. After 24 hrs immersion in 2% methylene blue, samples weresectioned and microleakage was estimated. Res

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Publication Date
Tue Mar 08 2022
Journal Name
Multimedia Tools And Applications
Comparison study on the performance of the multi classifiers with hybrid optimal features selection method for medical data diagnosis
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