الأوراق العلمية


عرضالصفحاتالأوراق العربية ... عنوان الورقة + الملخصر.م
من 5 ـــ الي 13
الملخص

في هذه الدراسة تم الكشف عن احتمالية الاستفادة من رماد قش الأرز كإضافات لتحسين الخصائص الفيزوميكانيكية للأسمنت البورتلاندي العادي. أظهرت النتائج بأن أفضل نسبة يمكن إضافتها من رماد قش الأرز كانت 20% من وزن الأسمنت وأفضل حجم حبيبي استعمل هو 0.125-0.063 ملم، وأن الإضافة أشارت إلى التحسن الواضح في الخصائص التماسكية والميكانيكية لعجينة الأسمنت المتصلبة. للاستكشاف من نتائج هذه الإضافة من المخلفات في صناعة الأسمنت كانت عملية مزدوجة الفائدة التي تشكل المخلفات الضارة للبيئة أولاً وبعد ذلك استغلالها في صناعة الأسمنت مع تقليل الإنتاجية للأسمنت ومن بعد ذلك تقليل المشاكل البيئية والاقتصادية التي شكلت الترتيب لصناعته.

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من 14 ـــ الي 24
الملخص

تستهدف هذه الدراسة إلقاء الضوء على استكشاف ملصق بيانات العبوات التجارية للمبيدات المتداولة بأسواق مدينة سبها – ليبيا عامي 2008-2009. قد أظهرت النتائج بالأعتماد على المادة الفعالة أن المبيدات الحشرية تأتي في مقدمة المبيدات المتداولة بالأسواق يليها المبيدات الفطرية ثم المبيدات العشبية ثم المبيدات الاكاروسية واخيرا مبيدات القوارض. ايضا وجد ان المبيدات من مجموعة المركبات الكارباماتية كانت الأكثر شيوعا يليها الفوسفورية ثم البيروثريدات و اخيرا الكلورونية العضوية, و معظم هذه المبيدات متوسطة السمية أو قليلة السمية بالنسبة للبيئة, و مازال يتوجد بالأسواق بعض المبيدات شديدة السمية المحرمة دوليا. أشارت النتائج إلى أن غالبية ملصقات عبوات المبيدات المتداولة بالأسواق أفتقدت واحد أو أكثر من البيانات المتعلقة بالرسومات الإرشادية pictograms? اللون المميز (الكودي)? المسئولية القانونية ? التناوب المحصولي و فترة الأمان.

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من 25 ـــ الي 42
الملخص

تقدم هذه الورقة تحليل لأداء منظومة طاقة حرارية مكونة من دورة رانكن البخارية، الدورة الغازية بمسترجع ودورة امتصاص لغرض تحقيق أفضل استغلال للطاقة الحرارية المحررة من عملية الاحتراق الوحيدة وذلك بهدف الحفاظ على مصادر الطاقة المحدودة والحد من التلوث الحراري، أنجزت هذه الدراسة باستخدام نسب انضغاط مختلفة للدورة العليا (لقيم مختارة لدرجة الحرارة القصوى T3) وأيضا إشراك دورات امتصاص بتقنيات مختلفة. أظهرت النتائج المتحصل عليها أن أفضل أداء للمنظومة المقترحة يكون عند استخدام قيم عالية لدرجة الحرارة القصوى بالدورة العلياT3 ؛ حيت يمكن استعمال نسب انضغاط مرتفعة، الحصول على بخار بدرجات حرارة دخول كبيرة للتربينة بدورة رانكن وأيضا إدخال دورات امتصاص بمعاملات أداء عالية.

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عرضالصفحاتالأوراق الاجنبية .... عنوان الورقة + الملخصر.م
من 5 ـــ الي 14
الملخص

The antioxidant effect of curcumin; the levels of different types of lipids and serum ALT activity were studied in Swiss albino mice infected with 100 cercariae of S. mansoni and treated with single dose of curcumin 20 mg/kg body weight after six weeks of infection. Superoxide dismutase enzyme (SOD) activity was improved non- significantly after treatment with curcumin. The activity of serum GPT was significantly(P<.001) reduced in S. mansoni infected mice after treatment with curcumin in comparing with the infected and treated with PZQ and those infected non treated group. Simultaneously, serum triglycerides and LDL were reduced significantly (p<0.05) after curcumin treatment and in comparing with mice infected and treated with PZQ. The level of HDL was significantly(P<0.001) elevated in mice infected with S. mansoni and treated with curcumin. On the other hand, serum level of cholesterol was also non- significantly decreased (p>0.05). The results of the present study demonstrate that curcumin may improve liver functions and the antioxidant status of the infected mice as well as the lipid metabolism of S. mansoni infected mice.

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من 15 ـــ الي 24
الملخص

This trial was carried out to detect and investigate the influence of chicken breed (Fayoumi and Dandarawi as Egyptian native breeds) on the ultrastructural properties of eggshells by using scanning electron microscope (SEM) technique. At 26 weeks of age, twelve samples of eggshells were randomly taken from the eggs collecting from the two breeds (6 each). The eggshell samples were prepared according to the scanning electron microscopy procedures to investigate ultrastructural variants. The main results obtained could be summarized as follows: The eggshell of Fayoumi breed had a significantly higher effective thickness (palisade layer %) compared to Dandarawi counterpart. Per contra, both absolute and relative mammillary layer length was significantly lower in eggshells of Fayoumi breed compared to those of Dandarawi ones. With regard to total structural score, the results revealed that Fayoumi breed had a significant better structural score (lower value) to overall ultrastructural traits. Where, the corresponding figures were 22.5 and 27.5 for Fayoumi and Dandarawi breeds, respectively. It can be concluded that the eggs of Fayoumi breed were required high force to break its eggshell, consequently, increased shell strength compared to Dandarawi breed. The previous result was attributed to Fayoumi breed was a better ultrastructural of eggshell and shell quality compared to the eggshells of Dandarawi breed.

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من 25 ـــ الي 37
الملخص

A survey study conducted on 10 apariares in Benghazi area including the first escapment of Al-jabal Al-Akhdar. Results indicate that honey bee infected by three species of mites. Varroa destructor, Tropilaelaps clareae, Tyrophagus putrescentiae. V. destructor accounted for 88.78% of the total samples. The mean of the total parasites collected throughout the study period was 0.3683±0.003327. The highest mean was recorded in June, 0.5317±0.005871 and the lowest was in February 0.1717±0.0055. Statistical analysis show significant differences between months, seasons, apariers and regions.

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من 38 ـــ الي 50
الملخص

The unmodified silica gel (for chromatography) and modified silica gel by poly acrylamide (PAAM) at optimum conditions were used to remove calcium (Ca2+) and magnesium (Mg2+) ions from aqueous solutions by the use of batch experiments at pH 10. The unmodified silica gel exhibited low percentage values about 15% and 17% for Ca2+ and Mg2+ ions removal, respectively comparing with that for modified silica gel 21.68% and 56.3% removal for Ca2+ and Mg2+ ions, respectively.

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من 51 ـــ الي 62
الملخص

Two types of refractory ceramic composites, namely mullite/zirconia and spinel/zirconia were prepared equimoleculary and investigated through their mineralogical composition and microstructure using XRD and SEM. Densification, mechanical and refractory properties were studied and correlated with their compositions and microstructures. Both composite samples show superior properties, especially after firing at 1600oC due to the high densification and well texture. However, the properties of spinel/zirconia are more outstanding. These advantages of such composites have widely recognized them for producing materials for refractory ceramics and engineering applications.

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من 63 ـــ الي 69
الملخص

The equilibrium constant for the triiodide formation was studied and determined using distribution coefficient and kinetics measurements. The equilibrium constant of iodine between water and carbon tetracholride was previously determined at 25o and values of 681 is obtained, also in this study the equilibrium will be determined by reaction between 3-chloroperbenzoic acid and potassium iodide under pseudo-first order condition using large excess of iodide. The best fit values for equilibrium constant that obtained from kinetics data at 25o is 680, the result shows that this values are very close to that obtained from distribution coefficient measurement methods.1 This results show the usefulness of kinetics method for determining the equilibrium constant for this reaction.

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من 70 ـــ الي 85
الملخص

Polyurethane (PUR) was prepared using polyo (polyester) and diphenylmethane 4, 4- diisocyanate (MDI) and modification with different sillica ratio. The casted samples were characterized by Instron 5566 machine to study mechanical properties of the modified polyurethane (Hardness, Elasticity, Strength, Elongation at break and Young Modulus). The Scanning electron microscopy (SEM) was used to study the morphology and structure the modified polyurethane. The Scanning electron microscopy indicated that the particles were dispersed and embedded well within the polyurethane matrix which enhance of the mechanical properties of the modified polyurethane.

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من 86 ـــ الي 96
الملخص

The problem of heavy metals contamination is a global issue and the challenge is to develop methods to remove heavy metals from soil and water. Recently, technologies using microorganisms and microbial products to remove metals have been successfully applied to waste water streams such as sewage sludge, and industrial effluents. The anionic bio-surfactants such as Rhamnolipids that are produced by the bacterium of Pseudomonas species has been used effectively for environmental applications, such as heavy-metal cleanup. The aim of this study is to investigate the ability of Rhamnolipid (bio-surfactants) to remove or reducing heavy metals (Cd2+, Pb, Ni2+, Ba, Zn and Sr). Different concentrations (20, 40, 80 ppm) of Rhamnolipid were tested to evaluate its efficiency heavy metals removal. The results showed that, 80 ppm of bio-surfactants reduced up to 53, 62, and 56% of Cd2+, Pb and Ni2+ respectively. while were 28, 20 and 7% for Ba, Zn and Sr at the same concentration level. Rhamnolipid could be used successfully as bio-surfactants of several heavy metals from contaminated water in 80 ppm concentration.

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من 97 ـــ الي 107
الملخص

The present work was planned to synthesize some heterocyclic compounds containing pyrrolo[2,3-d]pyrimidines. Our approach to the synthesis of the target compounds started through the hydrolysis of 6-ethylthio-4-methyl-2-(p-methoxyphenyl)pyrimidine-5-carbonitrile by refluxing in ethanol containing sodium hydroxide to give the corresponding sodium salt derivative which in turn was acidified to give 5-cyano-4-methyl-2-(p-methoxyphenyl)pyrimidin-6(H)one. Chlorination of the 5-Cyano-4-methyl-2-(?-methoxyphenyl)pyrimidin-6(1H)-one afforded 6-Chloro-4-methyl-2-(p-methoxyphenyl)pyrimidin-5-carbonitrile, which reacted with ethyl glycinate hydrochloride to give Ethyl (5-cyano-4-methyl-2-(p-methoxyphenyl)yrimidin-6-yloxy)acetate, which underwent cyclization to give the ethyl 5-amino-4-methyl-2-(p-methoxyphenyl)-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylate. The reaction of 5-Cyano-6-chloro-4-methyl-2-(?-methoxyphenyl)pyrimidine with piperidine, and morpholine, gave the 4-Methyl-6-(morpholin-4-yl)-2-(?-methoxyphenyl)pyrimidine-carbonitrile and 4-Methyl-6-(morpholin-4-yl)-2-(?-methoxyphenyl)pyrimidine-5-carbonitrile respectively. The Ethyl 5-amino-4-methyl-2-(?-methoxyphenyl)-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylate was used as key intermediates in the synthesis of other pyrrolo[2,3-d]pyrimidine derivatives, pyrimido[4\,5\:4,5]pyrrolo[2,3-d]pyrimidines and triazolopyrro lopyrimidines by reaction with different reagents . Seven compounds were selected and screened in vitro for their antimicrobial activity against four strains of bacteria and two fungal species .

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