In the current work various types of epoxy composites were added to concrete to enhance its effectiveness as a gamma- ray shield. Four epoxy samples of (E/clay/B4C) S1, (E/Mag/B4C) S2, (EPIL) S3 and (Ep) S4 were used in a comparative study of gamma radiation attenuation properties of these shields that calculating using Mont Carlo code (MCNP-5). Adopting Win X-com software and Artificial Neural Network (ANN), µ/ρ revealed great compliance with MCNP-5. By applying (µ/ρ) output for gamma at different energies, HVL, TVL and MFP have been also estimated. ANN technique was simulated to estimate (µ/ρ) and dose rates. According to the results, µ/ρ of all epoxy samples scored higher than standard concrete. Both S2 and S3 samples having higher values of µ/ρ, show minimum dose rate values. (µ/ρ) and RPE% values were enhanced, the concrete containing E/Mag/B4C (S2) had the best results, while the concrete containing Ep (S4) provide the worst results. The ANN prediction results take 15 sec for estimating gamma doses corresponding to seventeen shield thicknesses, while the theoretical MCNP-5 results took approximately between 7 to 10 hours for five gamma doses. ANN provides excellent predictions with a high degree of correlation depending on increasing the number of attenuation parameters used in the training process. Also, it predicts gamma dose rates for a large number of shield thicknesses that cannot be calculated theoretically in a very short time. This supports, the created epoxy composite offers good attenuation properties for many shielding applications and could be proposed as an injecting mortar for cracks in biological shields and the walls of diagnostic and radiotherapy rooms. However, further investigations are planned for different filler ratios, for comparison purposes, in order to reach optimal shielding properties
التنظيم القانوني للمهني – دراسة مقارنة في نطاق الاعمال التجارية
يتناول البحث مدى المسؤولية المدنية المترتبة على وزارة الداخلية عن اعمال منتسبيها
The term of ability (Al qoudra) is of the common terms which used by speech scientists to relate to one of the important verbal issues which called “Fate and destiny”. the issues of fate and destiny has been raised by Muslims since the dawn of Islam and It was researched among speech scientists, there are many opinions about this issues as the man can do or leave anything or he forced to do something that mean he hasn’t ability.
Also the term was used by jurists and they mention to the ability conditions (Assigning the Divine) and when this conditions are not available that means the man is not commissioning, the conditions are Mind, puberty and other conditions which mentioned in the books of jurisp
... Show MoreThe current rasearch which is entitled " The stylistic change in Kandinsky and Mondrian paintings – A Comparative Analytic study-" deals with the nature of change concept, its mechanisms and its constructive disciplines. The research has four chapters: The first chapter deals with the methodological Framework represented by the problem of the research which is concerned with the stylistic change and its role in activating formative disciplines. The research aims at, finding out the stylistic change in Kandinsky and Mondrian Paintings.&
... Show Moreعرفت النظم القانونية انواعا مختلفة من الشركات اذ تعتبر الشركة الوعاء القانوني الاكثر ملائمة لغرض توظيف اموال المستثمرين في مشاريع ذات اهمية والذي يحقق نفا لاصحاب رؤوس الاموال المستثمرة فضلا عن اثرها البالغ على اقتصاد الدول وقد كان للشركة القابضة نصيب من هذا الاهتمام منذ القدم لدى العديد من الدول ووضعت لها احكاما تفصيلية تتناسب مع الاهمية التي يحظى بها هذا النوع من الشركات كونها تجمع لعدة شركات فرعية تسيطر ع
... Show Moreاسلوب الحوار في القرآن الكريم اسلوب حياة وفي حقيقة الامر يضم القرآن الكريم بين دفتيه حوارات كثير مابين الله عزوجل وخلقه وما بين الانبياء واقوامهم وما بين الانبياء والطواغيت ومابين المؤمنين والكفار وهكذا ، وبدء الخلق قام على حوار مابين الله عزوجل وآدم وما بين آدم وابليس وما بيا الله جل وعلا والملائكة .
Experimental work has been performed on three capillary tubes of different lengths and diameters using R-12 and R-134a. The test also studies the effect of discharge and speed of evaporator fan. The results clearly showed that refrigerant type and discharge significantly influence the temperature drop across the capillary tube. While the speed of evaporator fan has small effect. Experimental results showed that the temperature gradient for the two refrigerants are the same, but after approximatly one meter the temperature gradient of R-134a is steeper than R-12.
Background: The isthmus is a difficult area in the root canal complex to manage. The research aimed to evaluate the efficiency of three different obturation techniques (lateral condensation, EandQ (thermoplasticized gutta percha system) and Soft Core (thermoplasticized core carrier gutta percha system)) to obturate the isthmus area of roots prepared by two different instrumentation techniques (rotary ProTaper universal and ProTaper Next systems). Material and method: Sixty freshly extracted teeth were randomly divided into two main groups (A and B) of 30 teeth each. Group A was prepared by rotary ProTaper Universal whereas group B was prepared by ProTaper Next system. Each main group was then randomly subdivided into three subgroups of 10 t
... Show More