In this study, the effect of the thermal conductivity of phase change material (PCM) on the performance of thermal energy storage has been analyzed numerically. A horizontal concentric shell-and-tube latent heat thermal energy storage system (LHTESS) has been performed during the solidification process. Two types of paraffin wax with different melting temperatures and thermal conductivity were used as a PCM on the shell side, case1=0.265W/m.K and case2=0.311 W/m.K. Water has been used as heat transfer fluid (HTF) flow through in tube side. Ansys fluent has been used to analyze the model by taking into account phase change by the enthalpy method used to deal with phase transition. The numerical simulation assumptions were three-dimensional, transient, and laminar flow was used. The result for the PCMs of performance, temperature distribution, and liquid fraction during the discharge process were compared to each other. Furthermore, the Nusselt number was analyzed. The result showed that the increase in thermal conductivity of PCM reduces the time of the solidification process by 20%. The performance of LHTESS for case 2 is 63.2%, whereas for case1 is 54.6%.
Violence is one of the most serious threats facing societies because it affects their internal structure and threatens the security and stability of society. It is classified as one of the types of security crises that are emerging in Arab and Islamic societies in particular, and in most countries of the world in general.
The threat of this crisis is increasing. Terrorism is considered as one of the most serious aspects of that all the countries of the world, currently, suffer from. The terrorism has begun to penetrate deep into society in one way or another starting from the Second World War, which led to the emergence of leftist movements in Western Europe, Japan, France, Italy and other countries as a result of emerging ideas
... Show MoreIn this paper, several combination algorithms between Partial Update LMS (PU LMS) methods and previously proposed algorithm (New Variable Length LMS (NVLLMS)) have been developed. Then, the new sets of proposed algorithms were applied to an Acoustic Echo Cancellation system (AEC) in order to decrease the filter coefficients, decrease the convergence time, and enhance its performance in terms of Mean Square Error (MSE) and Echo Return Loss Enhancement (ERLE). These proposed algorithms will use the Echo Return Loss Enhancement (ERLE) to control the operation of filter's coefficient length variation. In addition, the time-varying step size is used.The total number of coefficients required was reduced by about 18% , 10% , 6%
... Show MoreThe study aims to identify the impact of the implementation of the integrated education strategy in the curriculum of the Arabic language for the seventh grade on the academic achievement in the schools of the capital Amman. The researcher adopted the experimental method, where two divisions of the seventh grade students were chosen from the secondary school for girls. The sample of the study was 60 students divided into two equal groups: 30 students represented the experimental group (A) and (30) students represented the control group. To collect the needed data, a test of (40) Multiple Choices was used. The results showed statistically significant differences between the mean scores of the experimental group who were taught acc
... Show MoreThe research aims to find out the impact of Lee’s cognitive strategy on the achievement of fifth-grade literary students in the module of history. The research community consists of the secondary female day schools of Al-Karkh Al-Oula Directorate General of Education. The size of the research sample comprises (45) female students of the fifth grade of the literary brunch, (21) students for the experimental group and (24) students for the control group. The researchers have chosen an experimental design with partial control to suit the current research and its goal. They used a unified tool to measure the achievement of female students, which consisted of (50) items characterized by sincerity and they extracted the stability of t
... Show MoreThe topic of the research aims to consolidate the concept of fair value, and then to identify the international financial reporting standard and its role in the application of fair value in the Iraqi local environment and the possibility of using it in determining the value of the company. To achieve the goal of the research, the analytical approach was adopted for the data and information that was obtained by the researcher by conducting interviews with a number of bank and department managers in a sample of Iraqi banks registered in the Iraq Stock Exchange, and then analyzed by adopting some quantitative financial methods. The researchers reached a set of conclusions, the most important of which was the impact of fair value accoun
... Show MoreThis study sought to determine the impact of spreading the culture of quality in improving the quality of tourism service in some hotels in Erbil governorate. The theme of excellence in providing service and attention to it has become the concern of most organizations in general and tourism service organizations in particular. Tourists try to establish the mental status of customers about their tourism organizations had to pay attention to the quality of service provided to the customer and work to develop them to the advanced stages of satisfaction and happiness of customers and this will certainly positively affect the improvement of service in the tourism sector, Of the research variables were examined statistically by distrib
... Show MoreThe child realize that the meals time provide golden opportunities to get the attention the child needs. However, many difficulties that may appear about eating food can be avoided, if the family used the right way in dealing with this problem. The study aims, in this case, at searching for the reasons that lies behind the child's obstinacy in eating his food and the attempt to study some variables that is related to the research topic.
The results are summed up as follows:
- The number of the sample children is 3 of both sexes between the ages of 3 to 6 years
Abstract
This research attempt to explain the essential aspects of one important model in management of Bank risks , that is (stress testing) , which increase the concentrate on it resulting the negative affects of Global financial crisis that it accuar in 2008 to study the application possibilities in iraqian banks to enhancing the safety and financial soundness Becuase the classical tools in Risk management don’t give clear image on Banks ability in facing risks, hence the Basel committee on Banking supervision focusing in agreement of Basel 2,3 on stress testing when it doing the internal capital adequacy assessment process (ICAAP) .
To achieving the reseach obje
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Objectives: The study is carried out to assess functional performance for heart's valve replacement patients and find out relationship with sociodemographic data and clinical data
Methodology: Descriptive design is carried out at cardiac surgery centers in Baghdad ; Ibn -Al Betar Specialized for cardiac surgery center and Al-Iraqi center for cardiac disease. its initiation from December28the 2013 to September 1st 2014,A non- probability (purposive) sample of 50 adults patients are attended cardiac surgery centers at Baghdad city and who have heart valves replacement. The data collection through development of questionnaire which is composed from three parts(socio demographic data, clinical information, functional performa
The article presents the results of studies of the species composition of phytopathogens of winter soft wheat grain affected by ear fusarium. For the first time, studies were conducted using a complex of electron microscopic, molecular genetics, and mycological methods. The species F. graminearum dominated in all samples (frequency of occurrence 42.8%). The species F. avenaceum (23.3%), F. sporotrichioides and F. equiseti (8.8% each) were noted with high frequency. Next in descending order of frequency of occurrence: F. oxysporum, F. boothii, F. poae, F. proliferatum, F. accumatum, F. incarnatum, F. vorosii, F. tricinctum, F. cerealis, F. sambuticum. For the first time, 7 species were found for the plain zone of the Pre-Caucasus: F.
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