Dual-energy x-ray absorptiometry (DXA) is an established modality for the assessment of bone mineral density. DXA has also been used for the detection of abdominal aortic calcification (AAC) using lateral images taken for vertebral fracture assessment (VFA). In this phantom study, the capability of VFA for the detection of AAC was investigated. A Perspex phantom of variable width in the range 15-30 cm was used to simulate abdominal soft tissue. Aluminium strips of thickness 0.05-2.0 mm were sandwiched between two halves of the phantom to mimic aortic calcification. VFA images of the phantom were acquired in single-energy mode and analysed by placing regions of interest over the aluminium strip and an adjacent area of Perspex. For each phantom width, the minimum detectable aluminium thickness was assessed visually and related to contrast-to-noise ratio (CNR). Linearity of pixel value with aluminium thickness was tested by linear regression and correlation. Repeatability was measured with five repeated scans for selected phantom configurations. The minimum thickness of aluminium that could be visualised increased with phantom width and varied from 0.05 mm at 15 cm Perspex to 0.5 mm at 30 cm Perspex; the CNR threshold was about 0.03. At all phantom widths, the variation of pixel value with aluminium thickness was strongly linear (r²>0.98, p
Karima Elmasri, William David Evans, Yulia Hicks(6-2017)

تحقيق الجودة في العملية التعليمية يتطلب توجيه كل الكوادر البشرية والمناهج الدراسية والعمليات والبنى التحتية للمساهمة الفعالة في تكوين وإعداد الكفاءات العلمية التي تؤدي دوراً بارزاً في تلبية احتياجات سوق العمل للنهوض بالمجتمع وتلبية احتياجاته, وحيث ان التغيير المخطط فى المجتمعات يبدأ فى الغالب من التعليم فقد أصبح محتماً على المؤسسات التعليمية إن أرادت مواكبة العصر أن تركز على أن يكون الخريج مميزاً ذو كفاءة عالية مما كان سبباً في ظهور هيئات ومؤسسات الجودة والاعتماد التي أخذت على عاتقها نشر الجودة وتأكيد تطبيقها وذلك وفقاً لمعايير معينة. يهدف هذا البحث بالدرجة الاولى إلى تحسين وتطوير أداء قسم الدراسات العليا لقسم الهندسة المدنية بكلية الهندسة (كحالة دراسية) بجامعة طرابلس وذلك بتطوير و توثيق محاور الاعتماد البرامجى لبرامج الدراسات العليا الصادر من المركز الوطنى لضمان جودة واعتماد المؤسسات التعليمية والتدريبية بليبيا،ووضع أسس للتوثيق للنظام المقترح. وتم في هذا البحث مناقشة مفهوم الإعتماد وأهميته وفوائده ومتطلباته وإتباع طريقة تحليل الفجوة للنظام القائم بقسم الدراسات العليا بالهندسة المدنية وتكوين صورة واضحة عنه، وتم السعى لتقليص الفجوة عن طريق وضع أسس للتوثيق للنظام المقترح استنادا على موصفات الأيزو ISO 2008:9001 متضمنه محاور الإعتماد البرامجى وإقتراح دليل للجودة وكذلك دليل لإجراء تأكيد الجودة وإجراء الدراسات العليا مساهمة في التطوير والتحسين، وقامت الباحثة بإقتراح بعض البنود للتقييم والتقويم للمساهمة في تحسين وتقييم العملية التعليمة. Abstract In light of the rapid developments that affect all aspects of our daily lives, the change become inevitable from individuals and communities to keep up with these rapid developments, and that's where the planned change in communities often begins from education. For the educational institutions if they are to keep pace with the times is to focus on to be a distinctive graduate with high efficiency, which was the reason for the emergence of the bodies and institutions of quality and accreditation that took it upon themselves to deploy quality and confirm its introduction according to certain criteria. This research aims primarily to improve and develop the performance of Graduate Studies, in the Civil Engineering Department at the University of Tripoli, by developing accreditation parameters for graduate programs of the center of quality assurance and accreditation of educational institutions in Libya. The research discussed the concept of accreditation and its importance, benefits, requirements, implementing accreditation program. Through a gap analysis of the existing system, and propose the foundations for documentation of the proposed system based on the quality management requirement ISO ISO9001:2008 including accreditation program parameter and a contribution in the development and optimization. The researcher proposed some Techniques for implement of the items for assessment and evaluation to contribute of the improvement and evaluation of the educational process.
أمنة منصور راشد (2013)

Two-stage concrete (TSC) is known by various names such as colcrete, Polcrete, preplaced aggregate concrete and prepacked concrete. It is different from traditional concrete in two fundamental ways, namely method of construction and mix proportion. Two-stage concrete (TSC) is defined as firstly, coarse aggregates are placed into the formwork and grout is applied to fill in the between coarse aggregate particles voids. Secondly, the percentage of coarse aggregates in the mix proportion of TSC is higher than that in normal concrete. The typical value is about 60% as compared with 40% in traditional concrete. As coarse aggregates are preplaced first, they can occupy up to 60–70% of the total volume. As coarse aggregates are not involved in the mixing process, TSC is environmentally friendly with lesser consumption of energy. With a higher content of aggregates, TSC reduces the use of cement by 20–30% and may minimize the temperature rise. Engineering properties of TSC, including its stress–strain relationship, is mainly governed by the properties of coarse aggregates as stress is transferred from the skeleton of aggregates to hardened grout. Main advantages of TSC include a higher volume of coarse aggregates and the ability to use larger size coarse aggregates. The latter also reduces the cost of crushing. TSC has beneficial properties such as low drying shrinkage, high bonding strength, high modulus of elasticity, and excellent durability. The method of TSC has proved particularly useful in a number of applications like underwater construction, and masonry repair, where placement by conventional methods is extremely difficult. The method is also applicable in case of massive concrete where low heat of hydration is required. It is studied the feasibility of casting two stage concrete with 100% steel slag as coarse aggregate. In term of formulation, to adopt two stage concreting method we could minimize the risk of concrete bleeding and segregation due to high water absorption and quite high density of slag aggregate. The effect of slag coal ash and foamed glass on the mechanical properties of two-stage concrete has rarely been reported. Thus, the development of an eco-efficient alkali-activated grout for two-stage concrete is a new research topic that has no robust results to draw solid conclusions and it should blaze the track towards a cleaner production of building materials with outstanding sustainability.
Hakim S. Abdelgader(1-2022)