تتناول هذه الدراسة إمكانية استخدام الأرض كوسيط تبريد لمبادل حراري في نظم تكييف بالمباني بديلا عن الهواء الجوي، وحيث أن تقييم الخواص الحرارية للأرض هامة جداً لمعرفة مدى نجاح هذا النظام فقد أجريت تجربة عملية للتحقق من ذلك. ومن اجل إنجاز هذه التجربة ثم دفن أنبوب عمودي في باطن الأرض ليتدفق من خلاله الماء عبر دائرة مغلقة، وتم تزويد المياه بكمية ثابته من الحرارة مناظرة للحرارة التي يفقدها المبادل الحراري في نظام التبريد الهوائي. غير أن الهدف من هذا الاختبار دراسة التغير في درجة حرارة المياه الداخلة والخارجة من الأنبوب المدفون في باطن الأرض أثناء تزويد المياه بالحرارة خلال فترة زمنيه، وهذا الاختبار يسمي باختبار الاستجابة الحرارية للأرض.لقد أوضحت النتائج المتحصل عليها أن درجة حرارة خروج المياه من الارض تكاد تكون ثابتة بعد فترة زمنية قصيرة من زمن الاختبار،وأن درجة حرارة المياه هذه ملائمة كوسيط تبريد لمبادل حراري في نظام تكييف المباني. كما أن ثبوت درجة الحرارة هذا يساعد في الحصول على حمل تبريد مستقر، وهو ما لا يتوفر عند استخدام الهواء الخارجي كوسيط للتبريد باعتبارهذا ذا درجة حرارة متغيره، وتم الاستفادة من هذا الاختبار في تقييم الخواص الحرارية للارض، وإن هذه الدراسة قد بينت أن الموقع الجغرافي الذي تم اختباره تميز بكفاءة عالية، ومشيرا لإمكانية استخدام هذا النظام في تكييف المباني. Abstract This study is investigating the use of ground as cooling medium in a heat exchanger system for air conditioning of buildings as a replacement to the ambient air. However, evaluating the ground properties is very important to known the range of success of this system. An experimental setup is conducted to realize the above. In order to perform this experiment, a pipe is buried into the ground where the water is flowing in a closed circuit. A constant quantity of heat power is supplied to the water equivalent to the rejected heat from the heat exchanger in the air heat pump system. However, the objective of this experiment is to study the change in the inlet and the outlet water flow temperature from the buried pipe in the ground, during the heat injection to the water for a specific time. This test is called the thermal response test of the ground.The test results are clearly indicating that the outlet water from the ground has a constant temperature after a short duration from the test period. This water temperature is convenient as a heat carrier for air conditioning of buildings. This constant water temperature is also assisting in obtaining a constant cooling load. This can not obtained in using the out side air as a cooling carrier where the air is of a changing temperature. This study is indicating that the test site has a high efficiency, and this system can be used for air conditioning of buildings.
عادل احمد سويسي (2008)

Abstract Erosion wear is recognized as an engineering problem for slurry handling equipments. It plays an important role in design and operation of slurry transportation systems. The present work reports experimental and theoretical investigations of erosion wear of carbon steel and stainless steel in sandwater mixture. However, carbon steel (AISI-CS1060) and stainless steel (AISI-SS316L). They have been chosen as target materials, and then studied the effect of various parameters that may leads to good understanding to the erosion behavior of ductile materials such as impact angle, particle velocity as well as erosion time on erosion wear. The impingement jet erosion test rig built at our laboratory in order to carry out the experimental results. Aluminum oxide (Al2O3) is used as erodent particles after it mixed with water for slurry preparation at various impact angles of 15°, 30°, 60° and 90°, the solid concentration range of (10-30) wt%, for sized ranging between of 800µm to1700µm in the velocity range of 5 m/s to 24 m/s, with periodic time of 10 minutes at room temperature. The data points that collected in this work showed that the experimental values are agreement with the ductile erosion behavior for both materials, also showed that the erosion rate increasing linearly with increases in impact velocity and erosion time, also showed scars were characterized by an elliptical shape at 15° and 30° whereas a nearly circular shape was observed at 60° and 90° due to the horizontal component of velocity at shallow angles has value more than the normal component of velocity whereas in contrast at high angles.
فاضل رزق شحات (2014)

Making decisions is considered as the key role in achieving the desired goals within any organization. Moreover, making decisions in oil & gas industry is becoming a key factor for improving the work performance throughout practicing the most effective tools and techniques. The main purpose of this paper is to identify how individuals making their decisions within operating oil and gas companies. The required data for this paper were acquired by conducting several interviews with decision makers, and a questionnaire survey was also developed, besides reviewing the related literatures. Decision making processes in Libyan oil & gas operating companies were being investigated. The main findings show that over half of participants always consider safety, security and uncertainty issues when making their decisions, meaning that, it is a good indication of taking precautions when making decisions. Additionally, the majority of participants always double check their information resources, which is also a good indication of increasing the quality decisions and enhancing the work performance. Based on the findings, a number of recommendations were proposed for improving the processes of making proper and effective decisions within this business area arabic 13 English 77
Rajab HOKOMA, Hanan Zawam Aburas(1-2019)