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Hydrodynamics, Mass and Heat Transfer in Reactive Distillation
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      The ethyl acetate synthesis via heterogeneous reactive distillation is studied experimentally using ethanol and acetic acid. Three types of cation exchanging resins were used as catalysts: Zerolit 225, Zerolit 226 and Ambylite 400. Experiments were carried out in two units of the same dimensions. Each unit consisted of three sections: rectifying, reactive and stripping sections of heights (60+25+20) cm respectively and 2.5cm column diameter. The first unit (column-A-) was a fractionation type and the second unit (column-B-) was packed column. The packing type was hollow glass cylinders with 10 mm height, and 4, 5 mm inner and outer diameter respectively.

      The experiments were carried out by using two operation modes. The semi-batch and continuous operation mode. In the first part of present investigation, the semi-batch mode was used to evaluate the catalyst type and to evaluate the performance of reactive distillation unit configuration (Fractionation and packed column). Results show that, the column-B- gave higher conversion rates than column-A-. This is attributed to the high surface area available for liquid vapour contact in packed type column, which leads to increasing mass transfer rates.  On the other hand, Ambylite 400 catalyst showed higher activity for esterification reaction than other two types of catalysts.

      The second part of work continued with column -B- only. It is well known that, the esterification process is regarded one of exothermic reactions. Therefore, the monitoring of the temperature distribution along column axial for all three types of catalysts showed that the temperature distribution was essentially the same due to steady state operation in continuous operation mode. On the other hand, the effect of reflux ratio on temperature distribution was clearly noted, that is as the reflux ratio increased the temperature distribution along the column was reduced for each type of catalysts.

      On the other hand, the experimental results point that, as a reflux ratio increases the conversion rates of acetic acid is increased too because such increasing is related to high mass transfer rates between  vapour and liquid along reactive distillation column.

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Publication Date
Thu Jul 02 2009
Journal Name
Journal Of Educational And Psychological Researches
توظيف رســوم الاطفال كوحدات تصميمية تعليمية في اقمشة ستائر رياض الاطفال
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مشكلة البحث

ان التصميم هو توالد افكار عدت اساس له حيث انها اشياء لها معنى لامور اقتضت الايعاز باعداد هذه التصاميم، اما المصمم فهو الشخص الملم بمباديء واسس التصميم من اجل تنفيذ هذه الافكار بطرق علمية مدروسة، الا ان هناك سؤالا يطرح هل بالامكان لاي شخص ان يرسم فكرة تصميمية؟

الجواب هو نعم فالتصميم ليس مقتصرا على المصمم فحسب بل ان باستطاعة أي شخص ان يعبر عن ما بداخله من افكار سواء ك

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Publication Date
Tue Aug 06 2024
Journal Name
مجلة دراسات في التاريخ والاثار
فلسفة بوكر تاليافيروواشنطن وآرائه في اصلاح الأحوال العامة للسود 1895-1900
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ناولت هذه الدراسة إحدى الشخصيات الأمريكية التي تأثرت بواقع السود. كان بوكر تاليافيرو واشنطن أحد الأمريكيين السود ، الذين ولدوا في ظل العبودية وتعرضوا للاضطهاد بعد إلغاء حقوق التصويت وإطلاق قوانين جيم كرو من قبل الولايات الجنوبية. ورأى واشنطن خلال عمليات إعادة الإعمار أحوال السود وكيف كانت معاناتهم قبل الحرب الأهلية في ظل ظروف العبودية التي شملت الإذلال ، والحرمان من حقوقهم المدنية والسياسية، فيما لم يختلف

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Publication Date
Sat Sep 30 2023
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
A proposed program to audit the performance of the hotel sector under crises (Applied Research)
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Abstract:

        The research sought to identify the crises that occurred during the research period and their reflection on the performance of the hotel Research sample as well as to identify the reality of auditing the hotel Research sample and the preparation of a performance audit program can be adopted in auditing the performance of hotels in light of crises, and the problem of the research lies in the lack of a program to audit the performance of hotels that takes into account the crises experienced by the hotel sector, The research was based on solving its problems on three hypotheses, the first is that the performance audit in light of the Covid-19 pand

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Publication Date
Sat Sep 30 2017
Journal Name
Al-khwarizmi Engineering Journal
Study the Effect of Multilayer Single Point Incremental Forming on Residual Stresses for Bottom Plates
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Abstract

 

Knowing the amount of residual stresses and find technological solutions to minimize and control them during the production operation are an important task because great levels of deformation which occurs in single point incremental forming (SPIF), this induce highly non-uniform residual stresses. In this papera propose of a method for multilayer single point incremental forming with change in thickness of the top plate (0.5, 0.7, 0.9) mm and lubrication or material between two plates(polymer, grease, grease with graphite, mos2) to knowing an effect of this method  and parameters on residual stresses for the bottom plates. Also compare these results for the

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Publication Date
Tue Sep 27 2022
Journal Name
Arab Science Heritage Journal
مفردات قرآنية في معلقة الحارث بن حلّزة اليشكري دراسة صرفية دلالية
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Due to the importance of the word and because it is the basic building block from which speech is formed, it has become the subject of the attention of many scholars, ancient and modern

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Publication Date
Sat Jul 15 2023
Journal Name
مجلة الدراسات المستدامة
الأمثلة النحوية المصنوعة عند عبد العليم ابراهيم في كتابه النحو الوظيفي
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كانت االمثمة ومازالت الػسيمة الػحيجة واالىع في ايزاح القػاعج الشحػية قجيسا وحجيثا ، فالسثال ىػ الصخيقة التي بػاسصتيا يفيع الستعمع ما يخيج ان يػصمو السعمع ، فالذخح الكثيخ والدخد ال يػصل الى بيان القاعجة مالع يعدز باالمثمة . وليحا فان اختيار السثال السشاسب في السكان السشاسب ال يتع بصخيقة عذػائية اذا يشبغي ان يكػن السثال ذا معاييخ ومػاصفات تشاسب السقام الحي قيمت فيو . مغ ىشا جاء ىحا البحث ليبيغ ما السػاصفات الت

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Publication Date
Fri Feb 08 2019
Journal Name
Journal Of The College Of Education For Women
الشخصیة النرجسیة وعلاقتھا بالسلوك الایثاري لدى الطلبة المتمیزین في ثانویات المتمیزین
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This study aimed to investigate the relationship between narcissistic
personality and altruistic behavior for a subject of (307) gifted high schools
students, including (139)male and (168) female students ,both the scale of
narcissistic personality and the scale of altruistic behavior (Hameed ,2002) were
checked for its validity and reliability ,and both the level of narcissism and the
level of altruism for the students were measured in compare to the medium average
and approved to be statistically significant at (0.05) level.
Results showed that there were no significant differences in the altruistic
behavior between males and females ,results showed significant differences in
narcissism levels between males a

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Publication Date
Sun Nov 04 2018
Journal Name
Arab Science Heritage Journal
الهجرة الهجرة العلمية في عهد الدولة الرسولية (626-858هـ / 1228-1454م)
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The scientific abandonment of the most important places of education and science in the Happy Yemen, which Manfred them from the rest of the Islamic Alomassar such kind of places Education existence, has contributed to a variety of factors paved the way for the emergence and originated scientific migration in the (fifth century AH / atheist century AD), and was in the forefront divisions witnessed by the Zaidi sect to if divided into three teams are (Almpartyah and inventor and Husseiniya) Because of differences doctrinal debates Pima including a heated end the fighting of the conflict between the parties,

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Publication Date
Wed Jul 01 2015
Journal Name
Journal Of Educational And Psychological Researches
مدخل في سيكولوجيــة طب الاسنــان علم نفس طب الاسنــان (Psychology Dentistry )
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When we study the history of dentistry we can investigate some methodology styles which  lead us to psychology – dentistry or take the relationship between psychology and dentistry, and this type of specialization  which is Medical psychology has its own methodology and subjects, as the historical sequence in this filed lead to how evolution occurred in this branch of medicine, which was accompanied by many factors , and this factor that contributed to the consolidation of the misconceptions about the social, family and the media culture and gave a distorted picture of Dentistry and the attending physician or dentist  and show  him as someone tough , ruthless and violent in his dealings and style , these pro

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Publication Date
Thu Jun 01 2023
Journal Name
مجلة العلوم السياسية
الرؤية الصينية للتقارب الأمريكي مع تايوان في إدارة الرئيس جو بايدن
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