The current study presents an experimental investigation of heat transfer and flow characteristic for subcooled flow boiling of deionized water in the microchannel heat sink. The test section consisted of a single microchannel having 300μm wide nominal dimensions and 300μm height (hydraulic diameter of 300μm). The test section formed of oxygen-free copper with 72mm length and 12mm width. Experimental operation conditions spanned the heat flux (78-800) kW/m2, mass flux (1700 and 2100) kg/m2.s at 31˚C subcooled inlet temperature. The boiling heat transfer coefficient is measured and compared with existing correlations. Also, the experimental pressure drop is measured and compared with microscale pressure drop correlations. The results showed that higher mass flux leads to higher boiling heat transfer coefficient, and the dominant mechanism is convective boiling. Also, the experimental pressure drop decrease with increasing heat flux in a single-phase region while it increases in a two-phase region. Comparing the experimental results in the experimental condition range, showed that an existing correlation provides a satisfactory prediction of heat transfer coefficient and pressure drop.
Population density represents an important indicator for determining the growth of the size of urban areas. Population density has a direct impact on the quality of life, and its excessive rise may lead to the deterioration of basic service facilities. The problem of the research is that the increase in the total population densities of the residential neighborhood may reflect negatively on the nature of the services provided to the residents in these shops, and thus the failure to achieve sustainability in the residential locality. The research assumes that the increase in population densities negatively affects the achievement of sustainability in the residential neighborhood.
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من الاهمية دراسة التاريخ كونه يمدنا بحلول للمشكلات المعاصرة في ضوء خبرات الماضي، ودراسة سلبيات وايجابيات هذه الحلول، وانطلاقا من مبدأ أن ذوي الإعاقة البصرية طاقة بشرية لابد من استثمارها بما يخدم تقدم وازدهار المجتمع، فمن الأهمية تسليط الضوء على هذه الفئة والإسهام بنقل صورة مشرفة عنها، قد تكون دافعا للآخرين ممن اوقفهم انطفاء شعاع النور والبصيرة عن اكمال حياتهم لشرارة امل تعيد لهم شغفهم في الحياة، وته
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The research aims to investigate the private sector attitudes toward operational contracting in special education schools. The research adopted the qualitative approach by using personal interviews with a sample of (45) private school owners and managers in Oman. The results of the research revealed that there is an agreement among the majority of respondents on the ability of the private sector to manage special education schools, the advantages of the partnership, as well as the need for guarantees to support this partnership. The government should fully assume it. The role of the private sector remains to raise the operational efficiency of schools. Opinions vary about the level of powers granted to t
... Show MoreThis paper shows the characteristics of temperature and adsorbed (water vapor) mass rate distribution in the adsorber unit which is the key part to any adsorption refrigeration system. The temperature profiles of adsorption/desorption phases (Dynamic Sorption) are measured experimentally under the operating conditions of 90oC hot water temperature, 30oC cooling water temperature, 35oC adsorption temperature and cycle time of 40 min. Based on the temperature profiles, The mass transfer equations for the annulus adsorbent bed are solved to obtain the distribution of adsorption velocity and adsorbate concentration using non-equilibrium
model. The relation between the adsorption velocity with time is investigated during the process of ads
Suffer most of the facilities of the high cost of inventory , which affects the high cost of the product and thus affects many administrative decisions , as well as suffer the facilities of the systems developed by the provisions of inventory control , and this problem is exacerbated in the construction sector where the inventory in the form of Construction spin of the Year for another it becomes difficult to control the cost effectively , and is the research problem in question follows: What are the implications of the use of the system in time inventory accounting system for the contracting company does kills Alrkaah to the provisions of the cost of inventory and what is the optimal approach to inventory control ? Find assumed
... Show MoreIn this study, high quality ZnO/Ag-NPs thin transparent and conductive film coatings were fabricated
Background: One of the drawbacks of vital teeth bleaching is color stability. The aim of the present study was to evaluate the effects of tea and tomato sauce on the color stability of bleached enamel in association with the application of MI Paste Plus (CPP-ACPF). Materials and Methods: Sixty enamel samples were bleached with 10% carbamide peroxide for two weeks then divided into three groups (A, B and C) of 20 samples each. After bleaching, the samples of each group were subdivided into two subgroups (n=10). While subgroups A1, B1 and C1 were kept in distilled water, A2, B2, and C2 were treated with MI Paste Plus. Then, the samples were immersed in different solutions as follow: A1 and A2 in distilled water (control); B1 and B2 in black
... Show MoreThe orient culture and heritage has directly influenced ,in a way or another , the literary works which recently have been noted by the oriental Jews inside and outside of Israel. Several Jewish writers, who came from the orient (especially from Iran ), have written their works while influenced by traditions and customs of the Iranian society, in which they were born , lived , and raised, and by the writers who were born in that society and then moved to Israel and lived there as a result of the Zionism and its notorious promises to gather Jewish people from all over the world to establish their national home at the expense of the Palestinian land and people.
That final
... Show MoreBackground: Chemokine (C-X-C motif) ligand (CXCL9) has an important role recruiting the T-lymphocytes and immune response after infection by inducing T-cells accumulation around the areas associated with infections. However, this role is poorly known in relation with Toxoplasma gondii infection and also in association with thyroid hormones, which the present study is focused on. Methods: Eighty-seven women were included in this study for the period between September 2021 and February 2022. Blood samples of uninfected healthy pregnant, in addition to aborted and pregnant women infected with toxoplasmosis, were collected. Sera were then obtained and stored at -10°C. Toxo-latex agglutination test was done, followed by detec
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