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)

This paper investigated the implementation status of Just-In-Time practices within the Libyan cement industry. The required data/information were gathered from the target factories through interviewing the most involved people in the decision making process within this business area, and through a questionnaire, developed for this survey in order to identify the actual application levels for the key-factors being considered as the most crucial for any successful and effective application. The findings showed that the cement industry suffers from many problems in managerial, manufacturing, and industrial operations. Among of them are lack of clear policies and strategic plans. Based on the findings, the paper recommended that the management body should pay more attention for providing all the requirements to qualify and train the related employees and personnel, providing the spare parts required for maintenance programs, and do not neglect the security aspect, and should focus on the safety issues within the work-place. The paper also suggested that clear policies and strategies should be well-formulated, adapting modern technologies and techniques for maximizing the efficiency and effectiveness throughout the cement industrial operations arabic 13 English 66
ٌRajab HOKOMA, Hala Mansour Amaigl(7-2018)

تتعرض هذه الرسالة لدراسة نظرية لنموذجين مختلفين للمجمعات الشمسية، المعدنية وغير معدنية . وذلك لتعين معاملات الأداء لهذه المجمعات مثل معامل فقد الحرارة, عوامل فقد الحرارة الكلية, الكسب الحراري, الكفاءة اليومية, واللحظية.وقد أظهرت هذه الدراسة أن المجمعات المعدنية الشمسية متفوقة من حيت معاملات الأداء على المجمعات الشمسية الغير معدنية, تحت ظروف الجريان القسري. وقد دلت هذه الدراسة أيضا على أن عوامل فقد الحرارة الكلية لكلا النموذجين تظهر تغيرا طفيفا عند التغير في معدلات التدفق. كذلك فإن معامل الفقد الحراري يعتمد بصورة كبيرة على معدل التدفق لكلا لنموذجين, عند استخدام خزانات ذات سعة صغيرة. كما تبين أيضا أن الطاقة المختزنة, في المجمعات غير المعدنية, يمكن أن يستفاد منها كطاقة حرارية مفيدة حتى بعد غياب أشعة الشمس.وقد قورنت نتائج هذه الدراسة النظرية بنتائج دراسات عملية سابقة, و وجد أن هنالك تطابقا جيدا بينهما, ما عدا تلك النتائج التي تم الحصول عليها في ساعات الصباح الباكر وساعات المساء. Abstract This thesis presents a theoretical investigation of metallic and non-metallic solar water collector models for evaluating its performance parameters. The determined parameters include heat removal factor, overall heat loss coefficients, heat gain, daily and hourly efficiencies.The present study reports that, under forced circulation test, the non-metallic collector has an inferior performance parameters when compared to that of the metallic one. It was also revealed that the overall heat loss coefficients of both collectors show weak dependence on the flow rate variations. It was also noticed that the heat removal factor for both models is more sensitive to the flow rate variations when small storage tank capacities are used.The stored energy in the non-metallic flat plate solar collector model constitutes a significant part of the useful energy, even after the diminishing of the solar intensity.Finally, a comparison of performance parameters of the theoretical and experimental studies showed good agreements for most hours of the day, except the results obtained at the early morning and late after noon hours.
نورالدين عبد الحفيظ عبود (2009)