الأوراق العلمية


عرضالصفحاتالأوراق العربية ... عنوان الورقة + الملخصر.م
من 1 ـــ الي 14
الملخص

تقدم هذه الورقة دراسة نظرية لمنظومة تبريد امتصاصي أحادية المفعول تعمل بزوج (بروميد الليثيوم-ماء) لغرض التعرف على أدائها، أنجزت هذه الدراسة باستخدام درجات حرارة تشغيل متغيرة لقيم مختلفة لدرجة حرارة التكثيف ودرجة حرارة الامتصاص لمستويين للضغط العلوي ومستوى واحد للضغط السفلي ولقيمة محددة لفاعلية المبادل الحراري للمحلول، أظهرت النتائج المتحصل عليها أن معامل الأداء للمنظومة المقترحة يتحسن برفع درحة حرارة التشغيل بالمولد، وأظهرت النتائج أيضا أن أفضل معامل أداء للمنظومة المقترحة يتحقق بأستخدام مستوى الضغط العلوي الأول عند درجة حرارة امتصاص منخفضة ودرجة حرارة تكثيف متدنية تحقق التبريد الدوني ومساوية لدرجة حرارة الماص، رفع مستوى الضغط العلوي بالمنظومة لم يحسن معامل أدائها

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من 15 ـــ الي 27
الملخص

صممت هذه الدراسة بهدف تقييم التأثير السمي الوراثي للمستخلص الايثانولي لبذور نبات الحنظلCitrullus Colocynths)) بالجرعات (100، 200، 300 ملغم / كغم من وزن الجسم) في خلايا نخاع العظم لجرذان الالبينو، وقد أظهرت النتائج أن معاملة الحيوانات قيد الدراسة بهذه الجرعات أدى إلى استحثاث عدد من الشذوذات الكروموسومية التركيبية والعددية، كما أدى إلي زيادة معنوية عند مستوى احتماليةP<0.05 في قيم المتوسط الحسابي للمجموع الكلي للشذوذات الكروموسومية لمجموعات المعاملة بالمقارنة بالمجموعة الضابطة، وقد كانت قيم المتوسط الحسابي للمجموع الكلي للشذوذات الكروموسومية للمجموعتين المعاملتين بجرعات(200، 300 ملغم / كغم من وزن الجسم ) هي الاعلى بالمقارنة بالجرعة (100ملغم / كغم من وزن الجسم).الشذوذات الكروموسومية التركيبية التي تمت ملاحظتها في هذه الدراسة تمثلت في الشظايا ، الحذف، الكروموسومات الحلقية ، السحق ، الكسر الكروماتيدي، الإلتحام السنتروميري، الثغر الكروماتيدي والإنفصال السنتروميري، بينما شملت الشذوذات الكروموسومية العددية الاحادي والمجموعي، كما أظهرت النتائج انخفاضا معنويا(P<0.05) في النسب المئوية لمعامل الانقسام للمجموعتين (200، 300 ملغم / كغم من وزن الجسم ) بالمقارنة بالمجموعة الضابطة و المجموعة (100ملغم / كغم من وزن الجسم )التي سجلت بدورها انخفاضا معنويا( P<0.05)مقارنة مع المجموعة الضابطة. نستنتج من هذه الدراسة أن نبات الحنظل الذي يستخدم على نطاق واسع ليس آمنا بشكل مطلق من الناحية الوراثية حيث أظهرت نتائج هذه الدراسة أن المستخلص الإيثانولي لبذور نبات الحنظل أدى إلى إحداث العديد من الشذوذات الكروموسومية سواء كانت عددية أو تركيبية كما أدى استخدام المستخلص وبجرعات عالية إلى كبح نمو الخلايا والذي قد يصل إلى إحداث الموت الخلوي.

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من 28 ـــ الي 40
الملخص

تحظى الثقة التنظيمية ، والإدارة الالكترونية باهتمام بالغ من قبل المنظمات بكافة أنواعها وعلى اختلاف أهدافها وأنشطتها وعملياتها بسبب ماتشهدة بيئة الأعمال من تغيرات وتطورات سريعة ، وقد تناولت الدراسة الحالية احد الجوانب المهمة وهو دور الثقة التنظيمية في التوجه المعاصر نحو تطبيقات الإدارة الالكترونية ، وتمتلث مشكلة الدراسة في الإجابة على السؤال الأتي : هل يوجد دور للثقة التنظيمية في التوجه المعاصر نحو تطبيق الإدارة الالكترونية ؟ وهدفت الدراسة إلى معرفة دور الثقة التنظيمية في التوجه المعاصر نحو تطبيق الإدارة الالكترونية وتكون مجتمع الدراسة من العاملين بالإدارة العامة بجامعة سبها حيث بلغت عينة الدراسة ( 40) مفردة وثم الاعتماد على الاستبانة لجمع البيانات ، وأعطيت لكل فقرة وزنا مدرجا وفق مقياس ليكرت الخماسي ، وثم تحليل البيانات باستخدام برنامج ( Spss ) بقصد التوصل إلى الحكم المناسب على استجابة عينة الدراسة على فقرات الاستبانة ومعرفة اتجاهاتهم ، وأظهرت نتائج الدراسة وجود علاقة قوية بين متغيرات الثقة التنظيمية والتوجه المعاصر نحو تطبيق الإدارة الالكترونية وكانت أهم التوصيات ضرورة الاهتمام بتقانات الاتصالات والمعلومات واستخدمها في دعم وتحسين مستويات العمل من خلال تعزيز الثقة التنظيمي بهذه المنظمات.

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عرضالصفحاتالأوراق الاجنبية .... عنوان الورقة + الملخصر.م
من 1 ـــ الي 11
الملخص

Clays (kaolins) are considered as one of the most important raw materials that could be considered as a suitable source for synthesis of both conventional and advanced ceramics. Nowadays, they are still used in the manufacture of ceramic products such as bricks, roofing tiles, porcelain, sanitary wares, wall tiles and floor tiles, and also are used in different industrial chemical processes. The present work focuses on the mineralogical analysis of clay material samples collected from deposits located in the south of Libya. The raw clay samples were investigated using x-ray fluorescence (XRF) and X-ray diffraction (XRF) as well as thermal analysis (DTA and TG). The results found that, the raw clay samples have different amounts of metal oxides percentage, and the character of the clays is typically kaolin mineral.

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من 12 ـــ الي 23
الملخص

Metal complexes of Cr(III), Mn(II), Co(II) and Cu(II) with the Schiff base derived from 4-(1-(naphthalene-3-yl)ethyleneamino(3-hydroxnaphthalene-1-sulfonic acid have been prepared and characterized on the basis of physical characteristics, micro-analytical data, molar conductivity, magnetic moment measurements, 1H-NMR, IR and UV-Vis spectrum data. The elemental analysis data showed the isolated complexes 1:1 [M:L] ratio. The obtained molar conductance values revealed the complexes of [Mn(L)(H2O)3Cl)] (H2O)3, [Cu(L)(H2O)4](H2O)3 are non-electrolytic nature. The results of magnetic moment measurements exhibited the existence of Cr(III), Mn(II), Co(II) and Cu(II) complexes have unpaired electrons. The infrared spectral data displayed the main coordination sites of 4-(1-(naphthalene-3-yl)ethyleneamino(3-hydroxnaphthalene-1-sulfonic acid towards Cr(III), Co(II), Mn(II) and Cu(II) ions. The electronic spectral results of ligand and its complexes showed ???* (phenyl ring), n??* (HC=N), The data suggest that the Cr(III), Mn(II), Co(II) and Cu(II) complexes have octahedral structure. The synthesized Schiff base and its complexes were tested against some pathogenic bacteria [Staphylococci, Proteus, Bacillus subtilis and Pseudomonas aeruginosa] which showed moderate to good antibacterial activity against all used types of bacteria except Bacillus subtilis.

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من 24 ـــ الي 35
الملخص

Polymer nanocomposites are broadly studied throughout the world till now. Polymer nanocomposites show unique properties combining the advantages of the inorganic nanofillers and the organic polymers. Nanocomposites are composites in which at least one of the phases shows dimensions in the nanometer range. These are high performance materials that exhibit unusual property combinations and unique design possibilities and are thought of as the materials of the 21st century. Many methods has been used to synthesis of polymer nanocomposites. Therefore, this review article will make an overview about prepare polymer-based nanocomposites and investigate the effects of addition of inert fillers (Titanium dioxide) on polymer crystallization (Polyethylene oxide). Differential scanning calorimetry (DSC) provides a rapid method for determining polymer crystallinity based on the heat required to melt the polymer. It was observed that the melting temperature of PEO in PEO/TiO2 (VI) anatse lower than that of PEO pure, but when addition TiO2 P25 the melting temperature of PEO in PEO/TiO2 P25 is higher than that of PEO pure due to the spherulites are known to have lamella structure for all polymers and the increase of lamella thickness when added TiO2 cause an increase in Tm.

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من 36 ـــ الي 53
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من 54 ـــ الي 67
الملخص

Poly(methyl methacrylate) (PMMA) nanoparticles were prepared by grafting methyl methacrylate from both aggregated silica and colloidally dispersed silica nanoparticles using atom-transfer radical polymerisation (ATRP). Cross-linking and macroscopic gelation were avoided using a miniemulsion system. The thermal and physical ageing behavior of the nanocomposites have been examined by differential scanning calorimetry (DSC). The addition of silica nanoparticles to PMMA can influence its thermal and aging properties. Grafting PMMA-aggregated silica revealed considerable increase in the glass transition temperature, whereas colloidally silica nanoparticles showed only a marginal improvement. Additionally, while dispersing PMMA in colloidal and aggregated silica accelerated physical ageing, grafting to aggregated silica significantly reduced ageing rates.

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من 68 ـــ الي 75
الملخص

The use of computers for handling image data in the healthcare is growing. However, the amount of data produced by modern image generating techniques is vast. This data might be a problem from a storage point of view or when the data is sent over a network. This paper using wavelet transform technique for medical images compression. MATLAB program, are designed to evaluate medical images storage and transmission time problem at Sebha Medical Center Libya. In this paper, three different Computed Tomography images which are abdomen, brain and chest have been selected and compressed using wavelet transform. Objective evaluation has been performed to measure the quality of the compressed images. For this evaluation, the results show that the Peak Signal to Noise Ratio (PSNR) which indicates the quality of the compressed image is ranging from (25.89db to 34.35db for abdomen images, 23.26db to 33.3db for brain images and 25.5db to 36.11db for chest images. These values shows that the compression ratio is nearly to 30:1 is acceptable.

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من 76 ـــ الي 80
الملخص

In this paper problem of edge detection in digital images is considered. Three methods of edge detection based on mathematical morphology algorithm were applied on two sets (Brain and Chest) CT images. 3×3 filter for first method, 5×5 filter for second method and 7×7 filter for third method under MATLAB programming environment. The results of above mentioned methods are subjectively evaluated. The results show these methods are more efficient and suitable for medical image which can be used for different other applications.

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من 81 ـــ الي 89
الملخص

In the recent years, more and moreinformation services require high-speed data access. Videostreaming is a real-time service with high-speed dataaccess which conveys information such as audio and videonetworks using Internet Protocol (IP). Using the streamingtechnology clients can play the video in real timecondition. However, it’s strongly influenced by thebandwidth. Insufficient bandwidth for the streamingprocess will cause losses and greater delay[1]. Therefore,in order the video streaming service to approach its idealconditions it is necessary to be applied on a network whichhas a high speed data access and large bandwidth. Suchconditions can be fulfilled by the WiMAX network802.16d, because it is the network technology based oninternational standard IEEE 802.16 which enable totransfer data to wireless broadband access as analternative to cable or DSL. WiMAX can provide thefollowing types of access : fixed, portable andmobile wireless broadband on the line of sight (LOS) andnon-line of sight (NLOS) conditions[2]. Based oncalculations, by varying the distance 1 km - 15 km betweentransmitter and receiver for LOS and 1 km - 5 km forNLOS, the value of the propagation losses on NLOS isfound to be much larger than on LOS. In LOS conditions,the value of bit error probability is smaller than the NLOSconditions for all types of modulation. The best conditionsoccur in LOS using QPSK modulation with 2.6 Mbps datarate with bit error probability 2.6184x10-45 and packetloss probability of video streaming is 9.12x10-4.

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من 90 ـــ الي 95
الملخص

The aim of the present study was to demonstrate the possible effect of some factors such as age, gender, blood sugar level, and duration of disease on the serum chromium level in type I and type II diabetic individuals from Murzuk area. In addition to chromium , serum levels of Fasting blood sugar (FBS) and glycosylated hemoglobin (HbA1c) were evaluated in 46 type I diabetic subjects (group 1) ,48 type II diabetic subjects (group 2) and 43 healthy individuals (control group) of both genders aged between (30-81) years. Data indicated that both diabetic groups have significantly higher (p< 0.001) levels of FBS and HbA1c compared with the con-trol group. No significant difference (p> 0.05) was found in serum chromium levels between Diabetic patients compared with healthy individuals, nor was there between type I and type II diabetic groups. The obtained data also indicate that age, gender, blood sugar level, and dura-tion of disease have no significant (p> 0.05) correlation with serum level of chromium in dia-betic patients.

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من 96 ـــ الي 104
الملخص

In fact , there are many ways to diagnose the infection of Trichomonas vaginalis like clinical and laboratory diagnosis. One of laboratory diagnosis direct examination by microscope due to scarcity of researches relative to these parasite within Libyan society. , thus this study has been carried out in order to discover the extent of propagation of this parasite between women visiting some Clinics and Medical Centers in the city of Sebha, between period of December 2013 to August 2014. A total of 300 samples of married women, who were attending Medical Centers. The specimens were taken from various Southern Libya regions (Sebha –Wadi El-Shati – Aubari and Murzuk), 243 doubled specimens, (swabs and urine) and 57 single specimens (swabs) from other patients. The results have shown the existence of the more parasite in the individual specimens at 5 % and in doubled specimens 4 % respectively. The statistical analysis has indicated the existence of moral difference , also these differences between pregnant and non-pregnant women have indicated who were infected by the parasite, its percentage among non-pregnants women highest than percentage of pregnant women with percentages of 4.5% and 3.3% respectively successively. Regarding to the propagation of the parasite according age categories, it was find out that the T. vaginalis infects women whose ages about 17-40 years, a category of 29-34 years was most infected with percentage of 6.3%, while the parasite was absent among the regarding women of 41 years and more. The women from Wadi El-Shati region were most infected with percentage of 7.6 % followed by Sebha and Aubari with percentage of 4% and finally Murzuk region with percentage of 3%. This study results showed Candida albicans in infected specimen with percentage of 15 % , the statistical analysis showed significant difference between presence and absence of Candida albicans among infected and uninfected with Trichomonas vaginalis.

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من 105 ـــ الي 111
الملخص

This paper deal with three plant species which have not been previously recorded from Libya. One genera and three species are added to the flora of Libya. They are collected in trips throughout Libya from 2007 to 2011. These are Verbesina ( Asteraceae ). The species also include Retama monosperma ( Fabaceae ) and Euphorbia punctata ( Euphorbiaceae ). Verbesina encelioides has ecological and medicinal, value, and it is considered drought tolerant plant, does not require large amounts of water, and in the folk medicine it uses in anti inflammatory action for both gum sores and in hemorrhoid treatment as well as for the treatment of spider bite symptoms.

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