The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica.
There are many studies that discussed the famous museum's graveyards in the Islamic worlds, to study the lives of these figures, there are many difficulties for their studies because the first we need the regularity and history information, and many sciences support, such as in language, geography information.
I am studying the research from Maraqid Al-Maaraf book by Harz Aldeen, the book has large members about the persons have graved in Persian Country in the middle ages, there are more than (30) figures in my study, I have studied every figure in this research depending on the sources and references books.
The Dictionary of Countries by Yaqut al-Hamawi is one of the most important sources that researchers rely on in everything related to geography in knowing the names of places and countries, and the important historical information it contains about different cities and countries
This paper deals with the modeling of a preventive maintenance strategy applied to a single-unit system subject to random failures.
According to this policy, the system is subjected to imperfect periodic preventive maintenance restoring it to ‘as good as new’ with probability
p and leaving it at state ‘as bad as old’ with probability q. Imperfect repairs are performed following failures occurring between consecutive
preventive maintenance actions, i.e the times between failures follow a decreasing quasi-renewal process with parameter a. Considering the
average durations of the preventive and corrective maintenance actions a
... Show MoreA simple all optical fiber sensor based on multimode interference (MMI) for chemical liquids sensing was designed and fabricated. A segment of coreless fiber (CF) was spliced between two single mode fibers to buildup single mode-coreless-single mode (SCS) structure. Broadband source and optical signal analyzer were connected to the ends of SCS structure. De-ionized water, acetone, and n-hexane were used to test the performance of the sensor. Two influence factors on the sensitivity namely the length and the diameter of the CF were investigated. The obtained maximum sensitivity was at n-hexane at 340.89 nm/RIU (at a wavelength resolution of the optical spectrum analyzer of 0.02 nm) when the diameter of the CF reduced from 125 μm to 60 μ
... Show MoreThe banking performance and deposits attraction are considered to be of great importance in banks management, also the banking performance is one of the indications that measure the ability of satisfying and full fill the banks goals and the range of approach and move away from those goals, Also there are some important factors that affects on deposits, such as financial performance ,The aim of the research is to measure and analyses the banking performance and showing its effective impact and its relation in attracting deposits.
For the satisfaction of the research goals a smple was selected from the Iraqi banks which represented in five private banks were their data been analyzed between the periods 2009 to 2013 ,th
... Show MoreOne of them one of the important books due to its containing valuable information written by the author. Information include the life of the Messenger (Peace be upon him)
The objective of this study is to apply Artificial Neural Network for heat transfer analysis of shell-and-tube heat exchangers widely used in power plants and refineries. Practical data was obtained by using industrial heat exchanger operating in power generation department of Dura refinery. The commonly used Back Propagation (BP) algorithm was used to train and test networks by divided the data to three samples (training, validation and testing data) to give more approach data with actual case. Inputs of the neural network include inlet water temperature, inlet air temperature and mass flow rate of air. Two outputs (exit water temperature to cooling tower and exit air temperature to second stage of air compressor) were taken in ANN.
... Show Moreاصبحت وسائل الاعلام في ظل المتغيرات الجديدة قادرة على صياغة وعي وثقافة وهوية الشعوب الى حد كبير في المجتمعات المعاصرة , وذلك نظرا لما تتمتع به من اليات مختصة في التأثير والمتمثلة عموما في التكرار المتنوع للرسالة الاعلامية وقدرة الخطاب الاعلامي في معالجة القضايا المختلفة فضلا عن تقديم المعلومات وغزارتها وشرحها المستفيض , وقد بات من الواضح جدا مدى التأثيرات الكبيرة التي من الممكن ان يحدثها تعرض الافراد للمواق
... Show More- مشكلة البحث
تشغل مادة طرائق التدريس مكانة متميزة في عملية التعليم والتعلم لما لها من دور كبير وفاعل في إيصال المادة العلمية إلى الطالب بنجاح .
وقد عزى بعض الباحثين التأخر الذي رافق طرائق تدريس التربية الإسلامية إلى ضعف إعداد المدرسين وتأهيلهم التربوي ولا سيما أن عدد غير قليل منهم من كليات غير تربوية فهم خريجو كليات العلوم الإسلامية والجامعة الإسلامية والإدارة والاقتصاد
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