The varied thermal conductivity (insulation) of silica aerogel with heating for different pH has been investigated, it has been depended on ambient pressure drying method in the preparing silica aerogel samples, also six different pH of samples (1, 2, 3, 7, 8 and 9) were treated under five degree of heating with (50,100,150,200 and 250) ᴼC. This technique is important to test the carry-outs hydrophobic silica to temperature without high-quality material changes in the basic characteristics. The hot-wire technique is used in this work to examine the thermal conductivity, Fourier Transform Infrared Spectroscopy (FTIR) depended to characterize the bonds and their artificial by heating. Results show that the samples affected by heating through decreasing the density leading to obtaining more insulation metal, moreover varied pH is an important role in thermal conductivity. The average thermal conductivity of all aerogel samples in this work is (0.01- 0.0061 mW m-10 C-1) this means that it is still below thermal conductivity for air equals to (0.02257) mW m-10 C-1 . Meanwhile, we concluded that the insulation property of silica aerogel is affected by heat treatment and gives it more thermal insulation property.
نزع السلاح بعد انتهاء الحرب الباردة " دراسة نقدية"
The subject of the tagged research (becoming and integration of the film in postmodern cinema) is summarized by studying the transformations and complementarity of the film in light of the emergence of the concern of postmodernism. Then the need for it, as well as the objectives of the research and clarify its limits, as well as its importance. Then the transition to the theoretical framework, which included two sections, the first topic was entitled: Postmodern Cinema Formation and Completion, while the second topic was entitled: Paradox in Postmodern Film.
After completing the theoretical aspect, the research concluded with a number of theoretical framework indicators that were adopted as a tool for analyzing the sample, then th
... Show Moreتنشر الدولة الفرنسية قواتها العسكرية في جميع دول القارة الافريقية بهدف السيطرة عليها وتحقيق مصالحها الشخصية
مرت العلاقات المصرية – الامريكية بمنعطفات مهمة كان لها تاثيرها الكبير في مسار تلك العلاقات ولعل اهمها حرب حزيران 1967 و حرب تشرين الثاني 1973 ،الا ان تلك العلاقات اخذت منعطفا مختلفاً خلال عهد الرئيس المصري انور السادات واستمرت تلك العلاقات حتى عهد الرئيس المصري حسني مبارك وشملت مختلف المجالات السياسية والاقتصادية والعسكرية والامنية ،بل وصلت العلاقة بين البلدين الى حد الشراكة..ومهما قيل عن تحسن العلاقات المصر
... Show Moreتنشر الولايات المتحدة قوات في جميع دول القارة الافريقية بهدف السيطرة الكاملة عليها وتحقيق اهدافها ومصالحها
: تفرض مرحلة إعادة بناء الدولة أو مرحلة بناء الدولة حالتين متقاربتين، لكن تختلف تجربة كل منهما عن األخرى، ففي الحالة األولى نعني بها أن دولة ما متكاملة المقومات سواء القانونية أو السياسية أو االقتصادية، وتمتلك هذه الدولة الشرعية القانونية واالعتراف الدولي، لكن تتعرض هذه الدولة لألزمة سواء كانت ثورة أو انقالب أو احتالل، وإلى السقوط ونهاية نظامها السياسي القانوني ومن ثم إعادة بناء الدولة ومنظومتها السياسية..
... Show MoreThe study aims to identify the extent of the availability of administrative empowerment and the implementation of remote supervision in relation to two variables with respect to the employees of the Saudi Ministry of Education. The study included (456) male and female supervisors. The questionnaire has been administrated to collected data related to the research aims. The results indicated that both the extent of the availability of administrative empowerment and the implementation of remote supervision is of an average degree. There is a significant correlation relationship (p<0.05) between administrative empowerment and remote supervision of the educational supervisors of the Saudi Ministry of Education. The research recommends that
... Show MoreThis study was investigated the role of garlic extracts on the reproductive functions, via the development of immature male mice (25 days old) un l puberty. Immature male mice were divided into 3 groups (n=25). Group 1 "control" was daily administrated with tap water. Group 2 was daily administrated with cold aqueous garlic extract. Group 3 was daily administrated with hot aqueous garlic extract. Each group was randomly consisted of 5 subgroups (n=5/ subgroup) and administrated for different periods i.e, 1, 2, 3, 4 and 5 weeks respectively. Animals were scarified after 24 h from last treatment. Our findings elucidated that, cold and hot aqueous garlic extracts, when administrated at 25 days old (Immature period) have different impact dep
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The work of this paper is an investigation to improve the condenser performance of the automobile air conditioning system by enhancing the air-side heat transfer from the condenser through the use of an air guide net installed in front of the condenser face which is basically an aluminum plate having a circular entrance shape for the air passage. The A/C system was examined under two types of test. The first test was conducted the air guide net, while the second was done with the air guide net. The performances of the A/C system under these tests were compared. For the second type of test, the experiment was carried out with three different size of air guide net, three different circular diameters (2, 3 and 3.5 cm) a
... Show MoreBackground: As photochemical reaction that can stiffen the cornea, CXL is the only promising method of preventing progression of keratectasia such as KC and secondary ectasia following refractive surgery. The aim of CXL is to stabilize the underlying condition with a small chance of visual improvement. Objective: To show the sequences of changes in visual acuity and topographic outcomes during 1 year post CXL for patients with progressive Keratoconus.Type of the study: Cross sectional studyMethods: CXL procedure was done for 45 eyes with progressive KC. The following parameters had been monitored pre operatively, 1, 3, 6 and 12 months postoperatively: K apex, K2, corneal thickness at thinnest location, anterior and posterior elevation po
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