An experimental investigation of the variation of argon discharge current with a glow and afterglow time intervals of a square discharge voltage was carried out at low pressure (6-11 mbar). The discharge was created between two circular metal electrodes of diameter (7.5 cm), separated horizontally by a distance (10 cm) at the two ends of a Pyrex cylindrical tube. A composite of two Gaussian functions has been suggested to fit and explain the variation graphs clearly. It is shown that the necessary times of glow and afterglow needed to attain a maximum discharge current are (70 us) and (60 us), respectively. The discharge current is observed to drop to the lowest value when the two times are serially longer than (85 us) and (72 us). Furthermore, the difference between the two times required to obtain a maximum rate of change in the discharge current, or a maximum discharge current, is deduced to be comparable to the breakdown time delay of gases reported in the literature. These observations can be useful for the design of plasma devices requiring specialized engineering.
Jeder Lernende, der in der Fremdsprache Deutsch kommunizieren möchte, wird sich auch mit der deutschen Aussprache beschäftigen (müssen). Wer eine gute Aussprache hat, wird nicht nur oft und zu Recht bewundert, er hat es auch leichter, die deutsche Sprache zu verstehen, und er wird gut verstanden. Aussprachefehler beeinträchtigen die Kommunikation, sie führen zur Unverständlichkeit von Namen, Wörtern und Äußerungen oder Mißverständnissen, sie bewirken Ermüdung und Konzentrationsverluste und beeinträchtigen die Sprachverarbeitung durch Assoziationen und Emotionen, die beim Hörer entstehen können.’’[1]
Diese vorliegende Forschung befasst sich mit der Wic
... Show MoreAddition of bioactive materials such as Titanium oxide (TiO2), and incorporation of bio inert ceramic such as alumina (Al2O3), into polyetheretherketone (PEEK) has been adopted as an effective approach to improve bone-implant interfaces. In this paper, hot pressing technique has been adopted as a production method. This technique gave a homogenous distribution of the additive materials in the proposed composite biomaterial. Different compositions and compounding temperatures have been applied to all samples. Mechanical properties and animal model have been studied in all different production conditions. The results of these new TiO2/Al2O3/PEEK biocomposites with different
... Show MoreThe aim of this paper is to derive a posteriori error estimates for semilinear parabolic interface problems. More specifically, optimal order a posteriori error analysis in the - norm for semidiscrete semilinear parabolic interface problems is derived by using elliptic reconstruction technique introduced by Makridakis and Nochetto in (2003). A key idea for this technique is the use of error estimators derived for elliptic interface problems to obtain parabolic estimators that are of optimal order in space and time.
A la fin du XVIIIe siècle, les penseurs français dont Rousseau et Saint-Pierre, commencent à mettre en question la civilisation européenne. Dans leurs œuvres les plus importantes, ces deux auteurs parlent de la société européenne d'une façon très banale. Ils font, par contre, une invitation à la Solitude et l'isolement dans la nature afin d'éviter la corruption de l'âme par la société mondaine. Ces écrivains-penseurs croient que la société peut gâter l'humanité de l'individu. Ils suggèrent à travers les images innocentes de leurs principaux personnages vivant dans la campagne, un monde idéal où il n'y a que pureté et chasteté. Dans les deux œuvres que nous avons choisies (Paul et Virginie de Bernardin de
... Show MoreWater resources would be differentiate in Morocco specially in Morocco which appear as form of eyes ,rivers as dissolved water of mountain.
The human takes care of water either as rains to store and use in necessity trying to bring it to Maracas by helping from state
The research deals with the Presidents of the Christians who called themselves (Ghaltka) in the book titled (orient chirsy patriarchs) that talked about their scientific practical biography adding to) that their completeness on the position of Ghaltka with its decrees and caliphs who were contemporaries to them ,as well as their places, deaths, cemeteries and their accomplishments In accordance with the powers granted to them and also it mentions the situation of The Abbasid caliphate with them and with the sons of their sect .
The Arabs muslim , throughout the historical ages, had many and varied contributions in various fields of science and knowledge, and in all scientific disciplines. They were preceded by scholars of other sects, so their books were translated into Arabic and they added to it many of their scientific research and writings that affected Arab and Islamic libraries, as these scientific research turned into basic references for the benefit of students of science in this field, and they did not stop at that, but built observatories, and invented They developed many astronomical devices in their time and observed the planets and stars, drew maps for them and determined their locations
مشكلة البحث :-
ظلت رغبة الانسان في المعرفة وفهم الكون الذي يعيش فيه ، ملازمة له منذ المراحل الاولى لتطور البشرية ، فالانسان بما يتمتع به من امكانات وقدرات وطاقات كامنة استطاع عن طريق تفاعله واحتكاكه الدائم والمستمر والخلاق مع البيئة المحيطة به ان يلاحظ ، ويتخيل ويتذكر ويفكر ويخطط ويبتكر ، مستفيداً من اخطائه في التعرف عليها ، وفي زيادة قدرته على التحكم فيها وتحسينها وتطويره
... Show Moreان نجاح رياض الاطفال في تحقيق اهدافها يتوقف الى حد كبير على معلمة الروضة التي تزود الطفل بالخبرات ، فهي تمثل الام البديلة للطفل ، وتقع على عاتقها مسؤوليات نفسية واجتماعية واخلاقية نحو اطفال الروضة ، لدلك فان معلمة الروضة تقوم بعدة ادوار في رياض الاطفال ، فهي ممثلة لقيم المجتمع وتراثه التي تسعى الى غرسها في الطفل .
وعليه فان ليس كل من تتقدم للعمل في رياض الاطفال تصلح ان تكون معلمة ناجح
... Show MoreAbstract
The health section is considered to be one of the most important section in the field of service economical and social unit because of its concern in the life of human begin and society and the process of determining t
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