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لقد كان لطبيعة العصر، وما فرضته المستجدات الحديثة بالمجتمع، ما أدي إلي توقف الوظيفة الأصلية للعديد من المباني ذات القيمة، ذلك التوقف الذي أصبح سببا في إهمال مثل تلك المنشآت، ومن ثم تلفها مما يهدد بزوالها، وما يقلل كثيراً من الطابع العام للمدينة العربية القديمة ويفقد نسيجها العام كثيرا من عناصره، وتعتبر إعادة التوظيف للمباني ذات القيمة أحد الوسائل الهامة للتعامل معها والحفاظ عليها كمدخل للتنمية المستدامة للمدن العربية. إشكالية البحث: إلي أي حد يمكن أن يساهم إعادة توظيف مباني ذات القيمة في الحفاظ علي الخصوصية الوطنية والمحلية الثقافية والعمرانية للمدن العربية القديمة ودفع عملية التنمية الحضرية المستدامة لها. هدف وعناصر البحث: يهدف البحث إلى دراسة إمكانية الحفاظ علي المباني ذات القيمة من خلال إعادة توظيفها وتأثير ذلك علي الحفاظ علي الهوية الثقافية للمدن العربية وبما يدر العائد المادي للحفاظ علي تلك المباني للأجيال القادمة. ويتعرض البحث لدراسة العناصر التالية: 1- ماهية عملية إعادة التوظيف للمباني ذات القيمة والهدف منها وماهية التنمية المستدامة. 2- الاستخدامات المقترحة لإعادة توظيف المباني ذات القيمة ومدي ملاءمتها لها. 3- تمويل مشروعات الحفاظ وإعادة التوظيف للمباني ذات القيمة بالمدن العربية. 4- العائد من إعادة التوظيف كمدخل للتنمية المستدامة للمدن العربية. 5- النتائج والتوصيات.

This book presents high-performance data transmission over plastic optical fibers (POF) using integrated optical receivers having good properties with multilevel modulation, i.e. a higher sensitivity and higher data rate transmission over a longer plastic optical fiber length. Integrated optical receivers and transmitters with high linearity are introduced for multilevel communication. For binary high-data rate transmission over plastic optical fibers, an innovative receiver containing an equalizer is described leading also to a high performance of a plastic optical fiber link. The cheap standard PMMA SI-POF (step-index plastic optical fiber) has the lowest bandwidth and the highest attenuation among multimode fibers. This small bandwidth limits the maximum data rate which can be transmitted through plastic optical fibers. To overcome the problem of the plastic optical fibers high transmission loss, very sensitive receivers must be used to increase the transmitted length over POF. The plastic optical fiber limited bandwidth problem can be decreased by using multilevel signaling like multilevel pulse amplitude modulation or by using an equalizer for binary data transmission.

This book describes the newest implementations of integrated photodiodes fabricated in nanometer standard CMOS technologies. It also includes the required fundamentals, the state-of-the-art, and the design of high-performance laser drivers, transimpedance amplifiers, equalizers, and limiting amplifiers fabricated in nanometer CMOS technologies. This book shows the newest results for the performance of integrated optical receivers, laser drivers, modulator drivers and optical sensors in nanometer standard CMOS technologies. Nanometer CMOS technologies rapidly advanced, enabling the implementation of integrated optical receivers for high data rates of several Giga-bits per second and of high-pixel count optical imagers and sensors. In particular, low cost silicon CMOS optoelectronic integrated circuits became very attractive because they can be extensively applied to short-distance optical communications, such as local area network, chip-to-chip and board-to-board interconnects as well as to imaging and medical sensors.

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In this study, performance assessment of a residential scale size solar thermal driven adsorption cooling system installed in hot arid and dusty area at Upper Egypt, and, in operation since summer 2012 until now is carried out experimentally for four years in operation, moreover, the gained operational experiences are presented. The system performance is expressed in term of the solar collectors' field thermal efficiency, actual chiller chilling capacity, the temperature of cold-water outlet from the chiller, chiller coefficient of performance (COP) and cooling-water temperature outlet from the cooling tower. The system performance results show that the daily solar collector efficiency during the reported period was ranged from about 50% to 78%. While, the average chiller COP was varied from 0.4 to 0.64 in combination with average chilling power ranged from 3.6 to 6.42 kW and average chiller outlet cold water temperature ranged from 19 °C to 12.12 °C correspondence to cooling tower outlet cooling water temperature ranged from 31.4 °C to 23.4 °C, respectively. In the cooling session of 2014, a 50 kW cooling capacity wet cooling tower is integrated into the system, and the measurements show that the outlet water temperature from the cooling tower is about 23.4 °C at ambient air dry bulb temperature of 35.7 °C and wet bulb temperature of about 19 °C. Consequently, under this new heat rejection condition, the chiller average cooling capacity and COP reaches were 6.42 kW and 0.64 with a chilled water temperature of 15 °C. Clearly from the system operation period, the heat rejection through the re-cooling sub-system has the main significant impact on the system performance in the hot arid areas. Therefore, it should be based on alternative heat sink recourses with appropriate cost performance techniques.

Being a country with limited freshwater resources, Yemen facing a water crisis due to rapid depletion of groundwater and the lack of surface water availability. Dhamar governorate, which is located about 100 km from the south of Sana'a (the capital), is one of the arid regions in the country. This research aims to explain the current situation of water resources and to get better planning for water resources management in the governorate. The rainfall is low and have spatial and temporal variation as well as the non-renewable groundwater abstraction is high. Previous studies in Dhamar plain showed that the total inflow and outflow were approximately 659.36 and 771.51 MCM/year respectively, which gives negative change in storage of about 112.15 MCM/year. Groundwater table declined in the last 40 years at a rate of 2.0 to 2.5 m/year, because of the high abstraction of groundwater from the entire area. It is predicted with the growth rate of 2% in water abstraction, which is normally expected in developing the economy, the shallow groundwater would be exhausted within the next 30 years. In Dhamar plain, it was found that the irrigation supply for irrigated areas of single, double and perennial crops were about 90, 95 and 95% from groundwater while the remaining percentage supplied from surface water. In general, the classification of cultivated area according to the sources of irrigation not only in Dhamar plain but in all the governorate in 2013 was about 27 and 73% from groundwater and surface water respectively, which was changed in 2015 to 39 and 61% respectively. This means that there is a probability stress on groundwater in the future in agriculture sector. Better water resources management and conservation with planning are very important to apply in the governorate to solve the problem of water shortage in the future and conserve the non-renewable water resources. From this study, different scenarios suggested to adopt with the scarce in water resources.

Being a country with limited freshwater resources, Yemen facing a water crisis due to rapid depletion of groundwater and the lack of surface water availability. Dhamar governorate, which is located about 100 km from the south of Sana'a (the capital), is one of the arid regions in the country. This research aims to explain the current situation of water resources and to get better planning for water resources management in the governorate. The rainfall is low and have spatial and temporal variation as well as the non-renewable groundwater abstraction is high. Previous studies in Dhamar plain showed that the total inflow and outflow were approximately 659.36 and 771.51 MCM/year respectively, which gives negative change in storage of about 112.15 MCM/year. Groundwater table declined in the last 40 years at a rate of 2.0 to 2.5 m/year, because of the high abstraction of groundwater from the entire area. It is predicted with the growth rate of 2% in water abstraction, which is normally expected in developing the economy, the shallow groundwater would be exhausted within the next 30 years. In Dhamar plain, it was found that the irrigation supply for irrigated areas of single, double and perennial crops were about 90, 95 and 95% from groundwater while the remaining percentage supplied from surface water. In general, the classification of cultivated area according to the sources of irrigation not only in Dhamar plain but in all the governorate in 2013 was about 27 and 73% from groundwater and surface water respectively, which was changed in 2015 to 39 and 61% respectively. This means that there is a probability stress on groundwater in the future in agriculture sector. Better water resources management and conservation with planning are very important to apply in the governorate to solve the problem of water shortage in the future and conserve the non-renewable water resources. From this study, different scenarios suggested to adopt with the scarce in water resources.