Experimental investigation has been carried out to study the effect og gamma ray radiations on silicon solar cells. The measured experimental data are compared with the theoretical results obtained by computer simulation programs before and after radiation. P-N junction silicon cell samples were used for the study showing degradation behavior for the output power and the short circuit current with less effect on the open circuit voltage as the radiation doses increases. Enhanced series resistance was added to the solar cell model due to deformation of I –V characteristics resulting from gamma ray radiations. Wide spread spectrum of doses were employed to study the effect of the radiation on the crystal deformation and damages on different parameters of solar cells. Study reveals an improvement in the output power and short circuit current due to post annealing effect of gamma ray radiations. The conclusion consist of suggestions to protect the solar cells in space satellites.
W. ABUGHRES, M. EL-MURADI, H. EL-FITOURI(9-1992)

Abstract Electric insulators are one of the main parts of over head Transmission lines, they must meet two requirements, first is the electric insulation for the conductors, and the second is to provide mechanical support for the over head lines. Insulators are subjected to various electric stresses of different origin such as operating voltages and an electric stroke waves due to Lightning storms. Therefore the insulators must perform well under all weather and environment conditions. In addition some times degradation occurs in the insulators performance due to accumulation of different types of pollutions on its surfaces. This project deals with two samples of silicone rubber insulators Have been exposed to the natural pollution for 6 years in continuously energized line working in Libyan transmission network. The test line is connecting between Khomes power station to Khomes switching substation it is 8.5 km long, the site is considered to be the most polluted site in Libya .Several tests have been done on this type of insulators to the effect of Libyan Environment on these insulators to decide if this insulator is suitable for working in the Libyan electrical grid.
عبدالمولى بشير على اوحيده (2010)

إن معدل البيانات والقدرات و التغطية و الكفاءة الطيفية في نظم الاتصالات اللاسلكية يمكن أن تتعزز مع الناقل متعدد الحوامل والهوائي المتعدد، وبالتالي يتعزز الأداء العام لمنظومات الاتصالات اللاسلكية بشكل كبير من خلال الجمع بين تقنيات أنظمة تساعد تقنية الهوائيات متعددة المداخل والمخارج في ، تجميع تقسيم ترددي متعامد و أنظمة الهوائيات متعددة المداخل والمخارج زيادة سرعة تدفق البيانات وحيث أن تقنية تجميع تقسيم ترددي متعامد تعمل على نشر القناة الترددية انتقائية التلاشى على العديد من الرموز في هذه الأطروحة، سيتم تقييم الاداء بالاعتماد على مستوى الوصلة ومستوى النظام، حيث يتمثل قياس الأداء في مقدار حصيلة البيانات ، ونصف قطر الخلية وقوة الإشارة بالنسبة إلى التداخل الضوضاء، كما يعتمد على معيار القدرة المستخدمة آخذا في الإعتبار نوع التضميين والترميز .في هذه الأطروحة تبدأ السيناريوهات من الوصلة وتمتد الي مستوى النظام في تقنية التطور طويل الأمد. لتحقيق ما ورد أعلاه: من خلال تحليل المعادلات وبرنامج المحاكاة لحساب صافي البيانات عند حافة الخلية وتغطية الخلية والسعة على الوصلة الهابطة، ثم بعد تنفيذ برنامج المحاكاه، لاحظنا الهوائيات المتعددة الإرسال تؤثر على سرعة وصول النقل وأخذا في الاعتبار أسلوب التضمين فعند الزيادة في عدد الهوائيات فان صافي البيانات تزداد أيضا ولكن يجب أن تكون متناسبة مع احتمالية الخطأ وكذلك تتحسن التغطية مع نقصان رتبة التضمين المستخدم. ان مستوى النظام مع حركة المرور المختلفة الإنتاجية للنظم وقدرة الشبكة تتحدد بواسطة عدد كتل الموارد ، حيث ان عدد هذه الكتل تعتمد على معدل سرعة بيانات الخدمة ومعدل سرعة البيانات لكل كتلة. تنتهي هذه الأطروحة بخاتمة وملخص للنتائج وكذلك بعض التوصيات وبعض المواضيع لدراسات مستقبلية كإمتداد لما تم في هذه الأطروحة. Abstract In wireless communication systems the data rate, capacity, coverage, and spectral efficiency; can be enhanced with multi-carrier transmission and multi-antenna, then the overall wireless communication system performance is greatly enhanced by combining OFDM and MIMO schemes, MIMO helps in increasing the throughput where as OFDM spreading out the frequency selective fading channel over many symbols. In this thesis evaluating performance of the system depends on both link and system levels, where the measure of performance is represented in the throughput, cell radius and the effective signal to interference plus noise ratio (SINR). It also depends on the employed capacity criterion and it takes into account the impact of adaptive modulation and coding. The worked scenarios start from a link level extending to a system level in 3GPP LTE. To achieve the above a number of tasks followed by observations are carried out. They start by analysis of the equations and a Matlab program is written to calculate the cell edge throughput, cell coverage and DL capacity. After the programs implementation, the multi antenna transmission effect is noted on the arrival throughput when taking into account the modulation technique. When increasing the order of the antenna and the throughput is also increased, but it must be traded off with the probability of error; Coverage has also improved by decreasing the order of the modulation technique. For the system level with different traffic, the overall throughput of the system and the capacity of the network are determined by the number of resource blocks (RBs). These RBs depend on the bit rate of the service and bit rate for each RB. The adopted scenarios in this thesis start from link to system, where the features are represented in a flexible base station and user configurations, channel modeling with path loss, user mobility, also at different transmitter and receiver (MIMO). The approaches are useful in single user and multi-user MIMO, then all of the above can be standardized by metrics: capacity, throughput, spectral efficiency, user QoS etc. Finally thesis conclusion and some future work as an extension of this work are presented.
هبه مدحت الزقلعى (2014)