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Article
Studying the effect of a cone inside the collector on the solar chimney performance
دراسة تأثير وضع مخروط داخل جامع شمسي على أداء المدخنة الشمسية

Authors: Mohammed H. Abbood --- Ali Basim M. Ali
Journal: journal of kerbala university مجلة جامعة كربلاء ISSN: 18130410 Year: 2018 Volume: 16 Issue: 1 Pages: 202-214
Publisher: Kerbala University جامعة كربلاء

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Abstract

Objective of this research is to investigate, both experimentally and theoretically, the effect of added cone inside collector on the Performance of a Solar Chimney Power Plant (SCPP). A small prototype of a solar chimney was built with chimney height of 6m, diameter 0.25m, and collector diameter 7.5m, covered with glass. The experimental data gathered under actual weather conditions in Karbala city. Analytical solutions were then used to solve mathematical governing equations of continuity, momentum and energy using fortran90, these results then compared with the experimental results. The experimental results show that the maximum differences between airflow temperature and ambient air reached 16.5℃, airflow air velocity 16.4 m/s, the available power 84.6 W at a collector angle of 32.7°and a small pebbles on the cone under the collector. In summary, airflow temperature, airflow velocity and available power increases by using a cone under collector with small pebbles

يتناول البحث دراسة عملية ونظرية لاداء المدخنة الشمسية من خلال نموذج تجريبي تم بناءه بالأبعاد التالية: طول المدخنة 6م وبقطر 0.25م ، قطر المجمع الشمسي 7.5م مغطى بالزجاج بوجود المخروط وعدم وجوده تارة اخرى. يتطرق البحث بشكل اساس الى تصميم ودراسة المجمع الشمسي وتاثيره على اداء المدخنة الشمسية من خلال عمل نموذج تجريبي تم تصميمه وبناءه لاختباره في الظروف الجویة للعراق في مدينة كربلاء المقدسة في فصل الشتاء. أيضا تم تصميم برنامج لحل معادلات حفظ الأستمرارية والزخم والطاقة نظريا من خلال برمجتها وهيكلتها في برنامج ( Fortran90) في الظروف الجوية نفسها، ومقارنة النتائج النظرية مع النتائج التجريبية المستحصلة من الجانب العملي. بينت النتائج ان اعلى تغير في درجة الحرارة ممكن الحصول عليه 16.5℃ وكذلك سرعة الهواء الخارج الخارج من الجامع الشمسي هي 16.4℃ م/ثا عند استخدام زاوية ميلان للجامع مقدارها 32.7° درجة في حين ان اعلى قيمة للقدرة تم الحصول عليها هي 84.6 واط بوجود المخروط الخشبي اسفل المجمع الشمسي وغطاء زجاجي مع ارضية مغطاة بالحصى. أيضا وجد ان بناء مخروط خشبي اسفل المجمع الشمسي لتقليل ارتفاعه عن الارض له تأثير كبير على الطاقة الناتجة حيث كان هناك تحسن بنسبة 46.1% مقارنه بين وجود المخروط وعدم وجوده لنفس الظروف.

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Article
EXPERIMENTAL STUDY FOR GROUND TYPE EFFECT ON SOLAR CHIMNEY POWER PLANT

Authors: Mohammed H. Abbood --- Mohammed R. Abbas
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 2 Pages: 103-113
Publisher: University of Kufa جامعة الكوفة

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Abstract

Solar chimney power plant is a technology capable to generate electric energy through a wind turbine using the solar radiation as energy source; nevertheless, one of the objectives pursued since its invention is to achieve energy generation during day and night. The ground under the power plant plays an important role on the energy balance and heat transfer, due to its natural behavior as a heat storage system. An experimental model was designed in Holley Kerbala city (Iraq), which consisted of a 3m collector radius with 8ᴼ collector inclination angle and a 6m height of chimney been constructed and collector periphery opening height 3cm. Three kinds of grounds was studied in this work: sand, mixed from sand and pebble and the third is black pebble. The results show that the highest airflow temperature inside the chimney reached was 66.8Co when using the black pebbles basement. The maximum basement temperature measured was 81.6Co for the mixed basement. Also, the highest temperature difference reached was 23.2Co for the same ground that have good performance during day light compared with pebble basement that have more energy saving in night.


Article
In Vitro Comparative Assessment of Composite Nanoleakage Using Various Dentine Surface Treatments

Authors: Mohammed H. Abbood محمد عبود --- Raghad A. Al-Hashimi رغد الهاشمي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2016 Volume: 28 Issue: 4 Pages: 49-55
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The treatment of dental tissues proceeding to adhesive procedures is a crucial step in the bonding protocol and decides the clinical success ofrestorations. This study was conducted in vitro, with the aim of evaluating thenanoleakage on the interface between the adhesive system and the dentine treated by five surface modalities using scanning electron microscopy and energydispersiveX-ray spectrometry.Materials and methods: Twenty five extracted premolars teeth were selected in the study. Standardized class V cavities were prepared on the buccal and lingual surfaces then the teeth divided into five main groups of (5 teeth in each group n=10) according to the type of dentine surface treatment that was used: Group (A): dentine was conditioning with Er, Cr: YSGG laser. Group (B): dentine was conditioning with (Er, Cr: YSGG laser + acid). Group (C): dentine was conditioning with (acid + Er, Cr: YSGG laser). Group (D): dentine was conditioning with acid etch. Group (E): dentine was conditioning with acid + 10% sodium hypochlorite. For All the teeth SBMP adhesive were used and restored with Z250 composite restoration then all specimens were subjected to thermocycling 500 cycles, at 5° to 55 °C. The teeth were soaked in silver nitrate suspension. Then the teeth sectioned bucco-lingually across the centre of the restorations. The specimens were characterized using scanning electron microscopy and the amount of nanoleakage was measured by EDX spectro-analysis to identify the existence of metallic silver particles.Results: Data were analysed statistically by one way ANOVA test and (LSD) Tests. The results showed that there were statistically highly significant differences among all groups of the present study.The resultshowed that the acid and laser (group III) exhibited the lowest mean value of nanoleakage at around (6.14 %), whereas the highest mean value of nanoleakage (12.83 %) was determined by the only acid (group IV).Conclusions: Treating the acid etched dentine with Er: Cr: YSGG laser showed promising results as it exhibits lowest amount of nanoleakage of the adhesive bonding system


Article
DESIGN, CONSTRUCTION, AND TESTING OF A PARABOLIC TROUGH SOLAR CONCENTRATOR SYSTEM FOR HOT WATER AND MODERATE TEMPERATURE STEAM GENERATION
تصميم، بناء واختبار منظومة مركزات شمسية ذات القطع المكافئ لإنتاج المياه الساخنة والبخار عند درجة حرارة متوسطة

Authors: Ahmed A. Shaheed احمد عبد الرزاق شهيد --- Raoof M. Radhi رؤوف محمد راضي --- Mohammed H. Abbood محمد حسن عبود
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 1 Pages: 42-59
Publisher: University of Kufa جامعة الكوفة

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Abstract

Three parabolic trough collectors, with its two axes sun manual tracking system were designed, constructed, and operated in order to generate hot water and moderate temperature steam. An experimental investigation for testing the performance of a PTC is presented. The tests have been carried out in NAJAF climatic conditions (32.02º N, 44.33º E) during selective days of August. The thermal performance of PTC evaluated according to the Standard ASHRAE 93- 1986 (RA 91) and the efficiency curve for the PTC was estimated. In the performance analysis of the PTC array, the effects of collector inlet temperature, ambient conditions, two cases for glass receiver and the variation in mass flow rate of the working fluid were investigated. The tests were performed by collecting the data from the outdoor measurements to evaluate the instantaneous thermal efficiency for PTC. A peak efficiencies close to (50%, 18.8%) were obtained for solar collectors with evacuated and non-evacuated glass receiver respectively at higher flow rate. The collector efficiency equation that is obtained in the present work agrees with other researches.

تم تصميم وبناء واختبار ثلاثة مجمعات حوضية ذات القطع المكافئ )) مع نظام يدوي بمحورين للتتبع الشمس، لغرض PTC توليد الماء الساخن والبخار عند درجة حرارة متوسطة. تم تقديم بحث عملي لاختبار أداء أل )). الاختبارات العملية نفذت تحت الظروف المناخية لمحافظة النجف الأشرف ( خلال أيام مختارة من شهر أغسطس. تم 32.02º N, 44.33º E) PTC حساب الأداء الحراري لل STANDARD ASHRAE 93 ( )) طبقا ل ( -) وتم إيجاد منحني الكفاء لل 1986 PTC) . PTC في تحليل أداء أل )) تم بحث تأثير درجة حرارة الدخول، الظروف المحيطة، حالتين للمستلم الزجاجي والتغير في معدل جريان مائع التشغيل. الاختبارات نفذت بواسطة جمع البيانات من القياسات الخارجية لحساب الكفاءة الحرارية اللحظية PTC لل 50 )). ذروة الكفاءات المستحصلة كانت ( % ،18.8 %) للمجمعات الشمسية مع المستلم المفرغ وغير المفرغ على التوالي عند معدل الجريان الأعلى. معادلة كفاءة المجمع المستحصلة في العمل الحالي تمت مقارنتها مع بحوث أخرى.

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