Since its invention by the Romans, concrete has been cast into all manner of formworks. Whether temporary or permanent, however, rigid formwork has been the traditional standard. Because concrete is the most widely used construction material, improvements in the economy of erecting concrete structures will have significant implications. One of the best opportunities for cost reduction is minimizing formwork costs—expenses that can represent about half the total cost of a concrete structure.1,2 Fabric formwork is a potential solution toward this goal. As a compounding benefit, fabric formwork can also enable the casting of structurally efficient, variable section building components.3 Taking advantage of fabric forms, however, is a joint task of concrete technology specialists, structural engineers, and architects. Fabric structures exhibit material and geometric nonlinearities when loaded, so forms must be designed based on experimentation or structural analysis using software capable of shape-finding.4,5 Education and research must focus on this barrier before the full potential of this formwork type can be realized. arabic 5 English 31
Hakim S. Abdelgader(7-2018)

The main purpose of this research is to improve the shielding of gamma rays by developing special concrete with high physico-mechanical properties using local aggregates. Various concrete mixtures are designed using heavy fine aggregate as a substitute for normal fine aggregate at rates of 20, 40, 60, 80, and 100%, by weight. Other concrete mixtures have been designed by replacing coarse aggregate with 50 and 60% of heavy fine aggregate. The properties such as density, compressive strength, and tensile strength of hardened mixtures were studied. Gamma ray attenuation has been studied on concrete mixtures after exposure to utilized radiation source comprised 137Cs radioactive element with photon energy of 0.662 MeV. From the results, we concluded that the density and compressive strength in addition to the linear attenuation coefficient of hardened mixtures increased with the ratio of replacing normal aggregate with heavy aggregate up to 60%. With an increase of the ratio more than 60%, compressive strength and tensile strength were reduced with the continued increase in density. On the other hand, density and the linear attenuation coefficient increased with the replacement of coarse aggregate by 50 and 60% of the heavy fine aggregate; while both compressive strength and tensile strength decreased. arabic 21 English 108
Hakim Salem Abdelgader Abdelgader (1-2019)

الموانئ هي المنافذ الرئيسية للتجارة الداخلية والخارجية للدول، وتؤدي دوراً مهماً جداً في النمو الاقتصادي لكثير من الدول المتقدمة؛ حيث تعمل بوابات تمر من خلالها التجارة الخارجية، مثل استيراد المواد الخام ومن ثم تصنيعها وتصدير الجزء الكبير منها بعد التصنيع، أما بالنسبة إلى الدول النامية فإن اقتصاد معظم هذه الدول يعتمد على التجارة المنقولة بحراً ومن ثمّ على الموانئ، ولا تستطيع أي دولة من الدول النامية أن تستورد المنتجات المصنّعة والبضائع الأساسية لسد احتياجاتها؛ وكذلك تصدير المواد الخام التي تمكنها من الحصول على العملات الأجنبية من دون مرافئ فيها أو بالقرب منها ولهذا فان هذا البحث يقوم بدراسة الموانئ بصفة عامة من حيث تصنيفها ومكوناتها الإنشائية وبصفة خاصة دراسة حواجز الأمواج وأنوعها ومميزاتها وعيوبها ولمعرفة مكوناتها لما لها من تأثير على حركة الملاحة بالموانئ وتسليط الضوء على الموانئ الليبية وتصنيفها والظروف البحرية والمناخية المؤثرة عليها ودراسة المشاكل التصميمية لبعض الموانئ الليبية والظواهر التي طرأت على حواجز الأمواج والحلول المقترحة لهذه المشاكل Abstract Ports are the main outlets for internal trade and foreign countries, and lead a very important role in the economic growth of many developed countries; where she works gates pass through foreign trade, such as import raw materials and then manufactured and exported a large part of them after processing, but for developing countries, the economy of most of these countries depends on the seaborne trade and then the port, nor can any of the developing countries to be imported manufactured products and essential goods to meet their needs; as well as export of raw materials to be able to get foreign currency without ports where or near.Therefore, this research is studying ports generally in terms of classification and components construction and particularly the study of breakwaters and Onoaha and advantages and disadvantages and knowledge components because of their impact on the traffic in ports and shed light on Libyan ports, classification and sea conditions and climatic influence them and study the problems design of some Libyan ports and phenomena that have occurred on breakwaters and proposed solutions to these problems.
سعاد عمرو امحمد سندوقو (2013)