A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.
The present paper discusses morphological and syntactic structures of time in Russian language. The morphological and syntactic structures are considered part component of time category in Russian language.
The morphological categories of time are formed through a various types of expressions .Tenses generally express time relative to the moment of speaking. In some contexts, however, their meaning may be relativized to a point in the past ,present or future which is established in the discourse .Some languages have different verb forms or constructions and that are opposed in meaning not in syntactic category. Hence, the present study traces and compares the syntacti
... Show Moreقياس وتحليل تأثير صدمات أسعار النفط الخام على راس المال البشري في العراق للمدة (1970 – 2021)
Abstract
The current research aims to identify the typical effect of Flower and Coscroft on expressive performance and the development of lateral thinking among literary fifth-grade students. To achieve the research objective, the researcher chose a sample of (90) female students from the fifth literary grade, with two experimental groups and a control group. The research groups are of six subjects. The research found that the two experimental groups have more expressive performance than the control group. Students of the first experimental group outperformed the students of the second experimental group in expressive performance and lateral thinking tests. In light of the findings of the research, the researcher
... Show MoreThe researcher tried to show the importance of using environmental taxes as an effective economic factor for reducing contaminators resulting from cars exhausts, and presenting a suggested pattern for environmental taxes as a nucleus and a starting point for a wider implementing of environmental taxes in Iraq. &nbs
... Show MoreIn recent years, the attention of researchers, governments and international non-governmental organizations has focused on the aggressive practices adopted by companies with the aim of evading the tax burden or from paying the tax obligations imposed on them by law, as the results of these practices are negatively affected by tax revenues. And that companies are part of the society in which they work, and they have rights and obligations, including paying taxes. The research community is the Iraqi private shareholding companies, and the research sample was 4 companies within the private sector and in the field and finance - banking, insurance, industrial and service, which are Ashur Bank, Al-Ahlia Insurance Company, Baghdad Soft
... Show MoreAn experiment in the semester, the second semester of the academic year (2022-2023), and the data used was not processed (the second test for two independent, inaccurate samples, the Bermon correlation coefficient, and the Spearman correlation coefficient), and the following results were reached: There is a statistically significant difference at the level of ( 0) average, 05) between the third grade who studied the plan for asking cluster questions, and between the average of those who studied the special feature according to the traditional method of selecting achievement, and enjoyed completing the specialization, choosing the experimental group, because the strategy of asking cluster questions is one of the externalities that... Lear
... Show MoreA la fin du XVIIIe siècle, les penseurs français dont Rousseau et Saint-Pierre, commencent à mettre en question la civilisation européenne. Dans leurs œuvres les plus importantes, ces deux auteurs parlent de la société européenne d'une façon très banale. Ils font, par contre, une invitation à la Solitude et l'isolement dans la nature afin d'éviter la corruption de l'âme par la société mondaine. Ces écrivains-penseurs croient que la société peut gâter l'humanité de l'individu. Ils suggèrent à travers les images innocentes de leurs principaux personnages vivant dans la campagne, un monde idéal où il n'y a que pureté et chasteté. Dans les deux œuvres que nous avons choisies (Paul et Virginie de Bernardin de
... Show MoreThe study tackles the market orientation and the organizational learning as independent variables each included three sub-dimensions, and the variable of business performance as affiliated variable. These three variables have interacted to form the framework around which the study revolves. Since the banking sector has become an important part of which service sector is made, as well as it represents the basic pivot for the process of building and the development of the economies of countries, the Iraqi banking sector have been taken to be the sample of this study. A nonrandom sample of nine Iraqi banks was chosen, including four state banks (Al-Rafdain, Al-RaSheed, Industrial Bank, and Agricultural), and five private banks (Bagh
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