The ratio of draft tube to reactor diameters is of decisive importance for the operation behavior of air lift loop reactors. The influence of draft tube geometry was investigated with respect to oxygen mass transfer and mixing time. The diameter ratio was varied between 0.33 and 0.80. The measurements were performed in two loop reactors with liquid capacities of 11.775 and 26.49 liters using aqueous with solutions of different coalescence behavior. The results show that there is no single diameter ratio which would produce most favorable conditions for the two process parameters. With respect to the more important requirements of aerobic cultures, i.e high oxygen mass transfer and efficient mixing, a diameter ratio between 0.5 and 0.6 is recommended. If high liquid velocities in the draft tube are required a ratio of 0.6 should be used.
The current study aimed to standardize the multi-position suicidal tendency scale MAST in the Saudi environment as well as to assess suicidal tendencies in adolescents. Moreover, the study aimed to test the psychometric characteristics of the scale among a sample of (490) high school and undergraduate students, in the adolescence who ranging in age from (16-21) years. The scale demonstrated satisfactory internal consistency in terms of validity and reliability tests. as the results showed of exploratory factor analysis to the four dimensions of suicidal tendencies loading on two factors that accommodate 74.60% of the overall variance of the scale (1) the attitude toward life, and absorbs 43, 20% of the total variance of the scale,
... Show MoreIn this study, sawdust as a cheap method and abundant raw material was utilized to produce active carbon (SDAC). Physiochemical activation was utilized where potassium hydroxide used as a chemical activating agent and carbon dioxide was used as a physical activating agent. Taguchi method of experimental design was used to find the optimum conditions of SDAC production. The produced SDAC was characterized using SEM to investigate surface morphology and BET to estimate the specific surface area. SDAC was used in aqueous lead ions adsorption. Adsorption process was modeled statistically and represented by an empirical model. The highest specific surface area of SDAC was 688.3 m2/gm. Langmuir and Freundlich isotherms were used to
... Show MoreThese days, it is crucial to discern between different types of human behavior, and artificial intelligence techniques play a big part in that. The characteristics of the feedforward artificial neural network (FANN) algorithm and the genetic algorithm have been combined to create an important working mechanism that aids in this field. The proposed system can be used for essential tasks in life, such as analysis, automation, control, recognition, and other tasks. Crossover and mutation are the two primary mechanisms used by the genetic algorithm in the proposed system to replace the back propagation process in ANN. While the feedforward artificial neural network technique is focused on input processing, this should be based on the proce
... Show MoreForeign trade is very important in global economies because of its impact on the sustainability of economic growth by stimulating economic activity, creating jobs and expanding production . On the other side , this policy is a major obstacle to many developing countries and the reason is due to the nature of the economies of those countries because they rely mostly on one or a few economic resources, which makes them rely mostly on exports to that resource while they import most of the needs of their local market Which makes them in a spiral of underdevelopment , dependence and economic exposure, which requires them to break that cycle and the launch of economic development Perhaps one of the most important means to a
... Show Moreهدفت الدراسة الى تصميم جهاز يحاكي مهارة حائط الصد، وإعداد تمرينات خاصة باستعمال الجهاز المصمم لتطوير دقة الرؤيا البصرية لمهارة الضرب الساحق لالعبي الكرة الطائرة الشباب. استخدام الباحثان المنهج التجريبي، بتصميم المجموعتين المتكافئتين الضابطة والتجريبية. تم تحديد مجتمع البحث من العبي نادي الصناعة الرياضي )فئة الشباب( بأعمار ) 17 – .ً واستنتج الباحثان ان استخدام التمارين 18( سنة. تم اختبار دقة الرؤيا البصرية ل
... Show Moreتعتبر لعبة كرة اليد من الالعاب الفرقية، وان هذه اللعبة تستند الى قاعدة اساسية وهي الاداء الصحيح للمهارات، وللتقدم في هذه اللعبة يجب تعلم وأتقان اداء المهارات للوصول الى مستوى افضل للتعلم، من خلال الدور الذي يؤديه اسلوب نموذج كولب لأنماط التعلم (التكيفي) الذي يعمل على تحديد اسلوب التفكير والمفضل لكل فرد وتاثيره في تعلم مهارة الطبطبة للطالبات، اذ يعمل على ايصال المعلومات والافكار الخاصة باداء المهارة وحس
... Show Moreملخص البحث: يعد اسلوب تدريب المقاومات المرنة واحد من اساليب تدريب القوة العضلية فهو النظام الذي يتم من خلاله استخدام تمرينات يتم ادائها ضد مقاومات متغيرة مثل الحبال المطاطية او اشرطة الساندو، ويمتاز هذا الاسلوب بتغير الشدة خلال اداء التمرين الواحد اي ان كلما تم مط الحبل المطاطي ازدادت مقاومته وبالتالي فان اللاعب يستخرج قوته اكثر كلما اقترب الى مركزية الحركة في التمرين وهذا هو جوهر الاختلاف بينه وبين استخد
... Show MoreThe research aims to diagnose the level of reflection of uncertainty management strategies (Ignoring uncertainty, knowledge generation , interaction , coping) managing of Organizational change strategies (power coercive, rational empirical, Normative reductive) to the importance of the two subjects and the importance of the expected results has been selected sample size (65) managers from Zain , Asia Cell Telecommunication (32 Zain and 33 company Asia),which alignment for the such a study being heavily dependent on the certainty or uncertainty subject . The researchers are attain there is the effect of uncertainty management strategies in Organizational change management strategies on the overall level in the two companies but have tended t
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