A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.
The determiner phrase is a syntactic category that appears inside the noun phrase and makes it definite or indefinite or quantifies it. The present study has found wide parametric differences between the English and Arabic determiner phrases in terms of the inflectional features, the syntactic distribution of determiners and the word order of the determiner phrase itself. In English, the determiner phrase generally precedes the head noun or its premodifying adjectival phrase, with very few exceptions where some determiners may appear after the head noun. In Arabic, parts of the determiner phrase precede the head noun and parts of it must appear after the head noun or after its postmodifying adjectival phrase creating a discontinu
... Show MoreEuphemisms are advantageous in people’s social life by turning sensitive into a more acceptable ones so that resentful feelings and embarrassment can be avoided. This study investigates the ability of Iraqi English learners in using euphemistic expressions, meanwhile, raising their awareness and the faculty members in English teaching faculties regarding the relevance of discussing the topics that demand euphemisation. This study comprised three stages: initial test, explicit instruction with activities, and a final test for the students’ development in this domain. A test has been distributed among 50 respondents, who are at the fourth year of their undergraduate study at the University of Babylon/ College of Basic Education. The lo
... Show MoreDie vorliegende Forschung erklärt ein sprachliches Phänomen im Deutschen und Arabischen, dessen Aspekte die Grund-Folge-Relation (Kausalität) im Allgemeinen sowie den wirkungslosen Gegengrund (Konzessivität) im Besonderen behandeln.
In diesem Kontext wird der Unterschied der verschiedenartigen Gründe der Kausalität im Deutschen, wie wirklicher Grund (kausal), möglicher Grund (konditional) und wirkungsloser bzw. unzureichender Gegengrund (konzessiv) gezeigt.
Die theoretischen Darlegungen der konzessiven Ausdrucksmittel in dieser Forschungsarbeit werden durch diverse praktische Beispiele aus der deutschen und arabischen Literatur fundamentiert.
Das Hauptziel dieser For
... Show MoreThis paper represents an experimental study on the application of smart control represented by the use of the fuzzy logic controller. Two-link flexible manipulators that are used in airspace and military applications are made of flexible materials characterized by low frequency and damping ratio. To solve this problem, this paper proposes the use of smart materials (piezoelectric transducers), where each link is bonded with a pair of piezoelectric transducers that act as a sensor and another as an actuator. As the arm vibrates because of the movement generated by the motor, this voltage is controlled by a regulator inside the LABVIEW® 2020 software and sends the output control voltage to the piezoelectric actuator. Experimental results
... Show MoreThe applications of hot plasma are many and numerous applications require high values of the temperature of the electrons within the plasma region. Improving electron temperature values is one of the important processes for using this specification in plasma for being adopted in several modern applications such as nuclear fusion, plating operations and in industrial applications. In this work, theoretical computations were performed to enhance electron temperature under dense homogeneous plasma. The effect of power and duration time of pulsed Nd:YAG laser was studied on the heating of plasmas by inverse bremsstrahlung for several values for the electron density ratio. There results for these ca
... Show Moreمشكلة دارفور من المشاكل الازلية التي تهدد كيان الوحدة السودانية
يهدف البحث إلى تحليل إمكانية استثمار الغاز الحيوي الناتج من مشاريع تصفية المياه العادمة في جنوب بغداد بوصفه مصدرًا متجددًا لإنتاج الطاقة الكهربائية ، مع التركيز على غاز الميثان بوصفه المكوّن الرئيس ذي القيمة الحرارية العالية . اعتمدت الدراسة على القياسات الميدانية لتراكيز غاز الميثان في مشروعي الرستمية والكرخ الرئيسية خلال فصلي الشتاء والصيف ، مع مقارنة القراءات بين مراحل المعالجة المختلفة، ابتداءً من ال
... Show Moreلقد ألقت أزمة جائحة كورونا بظلالها على قطاع التعليم بصورة عامة، والتعليم العالي بصورة خاصة؛ إذ دفعت اغلب الجامعات والقطاعات التعليمية التابعة لها لإغلاق أبوابها او العمل فيها بصورة متقطعة، وذلك حفاظا على سلامة الموظفين والتدريسيين والطلبة من الإصابة بمخاطرها التي بات انتشارها يشكل وعلى الرغم من أهمية تكنولوجيا المعلومات والتعليم الالكتروني في التعليم الجامعي، الا ان ذلك التعليم المتمثل باستخدام مختلف تك
... Show Moreيهدف هذا البحث إلى عرض ودراسة أهم مظاهر التيسير عند الدكتور محمد عيد في كتابيه التعليميين (النحو المصفى،ونحو الألفية )ودراسة بيان مدى فائدتها للمتعلمين وأثرها في تيسير النحو العربي ومن هذه المظاهر:الاستعانة بطرائق التدريس في تيسير النحو مثل :(تنظيم الأفكار ،والإكثار من التدريبات والتطبيقات العملية ،واستعماله المخططات البيانية والجداول )وتصفية كتابيه من الزوائد ک(الاستطرادات،وفلسفات العوامل ،والتعليلات ،
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