استخدام المواد المركبة في التطبيقات الصناعية نمى بشكل سريع وذلك لمميزاته المناسبة التي تشمل ارتفاع نسب المقاومة والمتانة بالنسبة للوزن , وقد أصبحت المواد المركبة بديل المواد المعدنية في العديد من التطبيقات. المواد الثيرموبلاستيكية المركبة تم دراستها في هذه الرسالة حيث استعمل البولي اثيلين كقالب ودعم بإضافة ألياف الزجاج بنسب مختلفة ( 10% , 20% , 30% ) , وتم دراسة تأثير إضافة ألياف الزجاج على الخواص الميكانيكية للعينات. تم الحصول على العينات المركبة باستخدام جهاز البثق وإجراء التجارب لتقيم جريان المنصهر عند درجات الحرارة العالية حيث لاحظنا زيادة الجريان بزيادة الضغط . كما تم تطوير علاقات رياضية لتمثيل علاقات الإجهاد – الانفعال للعينات المركبة المتحصل عليها ,تم الحصول على ثوابت هذه العلاقات الرياضية. كما تم دراسة علاقات زمن الانهيارات للعينات المركبة , وتم تحسين طاقة الكسر للمواد المركبة التي تؤخر من ظاهرة الانهيار. إضافة ألياف الزجاج أدى إلى زيادة زمن الانهيار وتقليل طاقة الكسر. Abstract The use of composite materials in industry applications has grown rapidly, owing to their favorable characteristics, including high strength and stiffness to weight ratios, composite materials have been considered replacement of metals in numerous structural applications.Thermoplastic composite was studied in this thesis where high density polyethylene is used as a matrix and reinforced with different percentages of fiber glass ranging from (10%, 20%, 30%). The influence of addition of fibreglass on mechanical and thermal properties was studied. A pilot plant extruder is used to prepare the needed samples, where experimental investigation is carried out to evaluate the melt flow and the impact behaviour of the melt mixture at high temperature in the extruder. The flow rate increased by increased pressure. A mathematical correlation was developed to represent the stress – strain correlations of the composites used in this work. The combined model would be able to predict the creep, relaxation and recovery of composite materials, the constants of the model was obtained in area where the retardation effect is dominating. Time to failure correlation with stress was studied for the prepared composite material and mathematical correlation is established. The energy absorbed at fracture is improved for the composite material leading to a considerable delay in failure phenomenon. When added fibreglass led to increase time to failure and decrease energy of fracture.
ابتسام خليفة ابولجام (2008)

Abstract This research was an attempt to use the currently available activity coefficient methods with universal sets of parameters to simultaneously predict ternary liquid-liquid equilibrium data. The focus of this research was to calculate phase equilibrium data within fair error using set of Parameters obtained from the above-mentioned models. The significance of this work is to study the liquid-liquid phase equilibrium of the ternary system at several temperatures and to test the capability of the various equilibrium models to correlate these data. A series of liquid-liquid equilibrium measurements were performed by changing the composition of the mixture.The prepared mixtures were placed in the extraction vessel and stirred for 2 h and then left to settle for 4 h. Samples were taken by a syringe from both the upper phase and lower layers. Both phases were analyzed using gas chromatography equipped. Liquid-liquid equilibrium for the ternary system acetonitrile + benzene + n-heptane was measured at 298,313,333 K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models. The UNIQUAC equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. NRTL models satisfactorily predicted the equilibrium compositions. In each of the mentioned the ternary system, the calculated and experimental data were compared. The root mean square deviation (RMSD) between the observed and calculated mole percent for NRTL, UNIQUAC was 1.44%, 1.35% for acetonitrile + benzene + n-heptane
عماد الدين محمد الزغداني (2014)

Abstract Against the background due to the energy crisis in the late 1970’s, the pinch analysis has emerged as a powerful tool for the integrated design of process heat networks which include heat exchangers, distillation columns, furnaces, etc..The key strategy of this methodology is to set energy targets prior to design based on basic thermodynamic principles.The subject of this thesis in to apply this analysis to one of the Libyan Refineries, namely Ras Lanuf Refinery, to assess energy utilization of such big energy – consuming plants and to explore the potential of energy as well as capital costs savings based on the finding of applying this analysis. Based on actual operating data collected from the plant and application of the procedure of the pinch analysis to this real case study where a minimum temperature difference approach in the Ras Lanuf refinery heat exchangers design of 10 (ΔT min =10 ) the following results were obtained. Actual rate of energy consumption of the base case design of the refinery is 9MW which is provided by burning fuel oil in the furnace, while the minimum target predicted by the pinch analysis should be 8MW. This amounts to just over 11% energy savings which equivalent to $462,000 per year reduction in the operating cost of the refinery
هويدة الهادي الحبيشي (2011)