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Article
Studying The Feasibility Of Powder Composite For Mechanical Damping Purposes
دراسَة جدوى مركّباتِ المساحيق لغرضِ التخميد الاهتزازي الميكانيكي

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Abstract

The present work is concerned with study some of the mechanical properties (Brinell hardness, Bending strength, Damping) for a metal matrix composite (Aluminum-powder). Firstly Fabrication and characterization specimens reinforced with rice husk ash (RHA) particles are dealt in the present study. The metal matrix composites (MMC’s) were prepared by addition of (0,1,2,3,4 and 5%) volume fraction of RHA particulates. The best mechanical properties for composite metal matrix at volume fraction (3.7%) R.H.A at hardness (70.76 HB) with bending (97.88 Mpa). Secondly estimated the damping constant and damping ratio in structure which is made volume fraction of R.H.A. The main objective of this paper is to estimate the damping ratio, natural frequency, damping constant of metal matrix composite reinforcement with different volume fraction of R.H.A by forced vibration analysis experimentally and theoretically, damping ratio is determine by using half-power bandwidth method. The damping ratio, natural frequency, damping constant proportional directly with volume fraction of R.H.A, best value for damping ratio (0.012) at volume fraction of R.H.A (5%).

ويهدف هذا العمل الى دراسة بعض الخواص الميكانيكية (صلادة ،قوة الانحناء و التخمييد) على المواد المركبة ذات مصفوفة معدنية (مسحوق الالمنيوم ). اولا تحضير المادة الداعمة (رماد قشر الارز RHA) ومن ثم تصنيع العينات مع المادة الداعمة يتم التعامل مع هذه المادة في الدراسة الحالية. أعدت مصفوفة المعدنية المركبة (MMC) بواسطة إضافة جزء حجمي ( 4،3،2،1،0 و 5٪) من مادة(RHA) .أفضل الخواص الميكانيكية للمعدن المركب في جزء حجمي (3.7٪) RHA لصلابة (70.76 HB) والانحناء (97.88 MPA). ثانيا تقدر نسبة التخميد المستمر والتخميد في مركب العينة في جزء حجمي مختلفة من( RHA) والهدف الرئيسي من هذا المشروع هو لتقدير نسبة التخميد، التردد الطبيعي، التخميد المستمر لتعزيز مصفوفة ذات المركب المعدني مع جزء حجمي مختلف من (RHA) بواسطة تحليل الاهتزاز القسري نظريا وعمليا. نسبة التخميد يتم تحديدها باستخدام نصف الطاقة طريقة عرض النطاق الترددي. نسبة التخميد، التردد الطبيعي، التخميد ثابت يتناسب طرديا مع نسبة ( RHA) وافضل قيمة لنسبة التخميد هي (0.012) عند نسبة خلط (5%).


Article
Mechanical Strength of Alumina Compacts Lubricated withPoly (methacrylic acid esters) Copolymers
المتانة الميكانيكية لمكبوسات آلومينية مزيتة بواسطة بولي( استرات حامض الميثاأكريليك )

Authors: Inaam M. Abdulmajeed أنعام محمد عبد المجيد --- Hadi S. Al-Lami هدى سلمات الامي
Journal: Iraqi Journal of Physics المجلة العراقية للفيزياء ISSN: 20704003 Year: 2010 Volume: 8 Issue: 11 Pages: 48-52
Publisher: Baghdad University جامعة بغداد

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Abstract

In recent years, there has been a rapid development in research on high performance ceramics for mechanical, electrical and medical industries. This development will be shown for alumina as a representative for oxide ceramics powders.
Dry–pressing forming technique was used to prepare different ceramic compacts for alumina grafted by polymethacrylate polymers. All Alumina compact were fired firstly at 1200 ْ C, then at 1600 ْ C.
Mechanical strength was examined in different means, some depends on compression and other depends on impact. Hardness was also measured .The results obtained were compared with that of Alumina compact prepared under the same condition from Alumina especially made for pressing .
The results revealed that the compacts lubricated with polymethacrylate copolymers had higher mechanical properties than that prepared from Alumina made especially for pressing, reflecting the good capability of those polymers to act as lubricant for Alumina particles, this was supported by scanning electron microscope.

حصلت تطورات سريعة في مجال بحوث استخدام السيراميك الفائق الدقة في معظم المجالات التطبيقية منها الميكانيكية ، الإلكترونية والطبية. وفي هذا البحث سيتم التعامل مع مكبوسات الألو مينا كمثال للمساحيق السيراميكية الأوكسيدية. شكلت الألو مينا المطعمة بالبوليمرات الميثاأكريليتية (كمادة مزيته للجسيمات السيراميكية) بطريقة الكبس الجاف لتحضير مكبوسات سيراميكية، حرقت النماذج أولاً عند درجة حرارة 1200 ْم ولبدت بعدها عند درجة حرارة 1600 ْم . فحصت المتانة الميكانيكية بعدة طرق منها ما يعتمد على الانضغاط والأخرى على الصدمة ، وكذلك قيست صلادة المكبوسات الألومينية المصنعة ، قورنت هذه مع مكبوسات ألومينية ناتجة من ألومينا خاصة بالكبس . فكانت الأولى أفضل بكثير من الثانية معطية الانطباع على القابلية الجيدة للبوليمرات الميثا أكريليتية للعمل كمادة مزيته للمساحيق السيراميكية. دعمت النتائج بالفحص المجهري للنماذج باستخدام المجهر الإلكتروني الماسح


Article
Study of Tensile Strength and Hardness Property for Epoxy Reinforced With Glass Fiber Layers
دراسة مقاومة الشد وخاصية الصلادة لمتراكبات الايبوكسي المدعمة بطبقات من الالياف الزجاجية

Author: Emad S. Al-Hasani
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2007 Volume: 25 Issue: 8 Pages: 988-997
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Tensile strength and hardness property were studied in an epoxy (DGEBA)resin as a matrix reinforced with glass fibers for different volume fraction aslayers.A comparison was done between woven roven samples, random layerssamples and sandwich composite samples which consists of (woven roven andrandom). Finally the results show that the sandwich composite gives highertensile strength, while the composite reinforced with woven roven fiber hasmaximum hardness values.

المستخدم في ( DGEBA) تم في هذا البحث دراسة مقاومة الشد وخاصية صلادة برينل لراتنجهذا البحث كمادة اساس والمدعم بالياف زجاجية على شكل طبقات بنسب حجمية مختلفة.تم اجراء مقارنة للنتائج بين المتراكبات المدعمة بالالياف الزجاجية (المتعامد ة والعشوائيةوالمتوالفة). وقد اظهرت النتائج ان مقاومة الشد لمتراكبات الايبوكسي المتوالفة اي المدعمةبالنوعين من الالياف تكون اعلى من المتراكبات المدعمة بالالياف المتعامدة والعشوائية.كما اظهرت النتائج ان المتراكبات المدعمة بالالياف الزجاجية المتعامدة تمتلك صلادة اعلى منالمتراكبات المدعمة بالانواع الاخرى.


Article
Assessment of the effectiveness of the manufactured chemo-mechanical caries removal on caries removal

Authors: Musab H. Saeed مصعب سعيد --- Haitham J. Al-Azzawi هيثم العزاوي --- Amer M. Al-Ani امير العاني
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2005 Volume: 17 Issue: 2 Pages: 1-4
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Chemo mechanical caries removal systems has been discussed as an alternative to conventional caries removal. This study assesses the efficacy of a chemo- mechanical caries removal technique in caries removal.Material and methods: Forty five decayed extracted human teeth were used in the present study. After initial opening through the enamel, different concentrations of the chemo-mechanical caries removal solution were placed in the cavity and excavation of the caries was performed.Results: After probing and visual inspection, with the use of the DIAGNOdent caries detecting device, and after histological examination, the concentrations of 0.5% and 0.7% were shown to be equally effective in removal of caries and more potent than the 0.2% concentration.Conclusion: 0.5 % concentration of the manufactured chemo- mechanical caries removal is the optimal concentration that can be used in dentinal caries removal.


Article
Histopathological examination of the chemomechanical caries removal effect on the human pulp

Authors: Musab H. Saeed مصعب سعيد --- Haitham J. Al-Azzawi هيثم العزاوي --- Amer M. Al-Ani امير العاني
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2005 Volume: 17 Issue: 2 Pages: 21-23
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Chemo mechanical caries removal systems have been discussed as an alternative to conventional caries removal. This study examines the effect of the chemo- mechanical caries removal material on the human pup.Material and methods: Forty eight maxillary first premolars from twenty four patient ( 18 male and 6 male) were studied and selected from patients need orthodontic treatment .class V cavity was done in each tooth and the material put inside the cavity for 20 sec, the extraction procedure done after 20minutes, 24 hours and 4 days .Results: The histological examination of 0.5 % Chemo-mechanical caries removal at the three periods showed that there is no significant effect on the pulp of the tooth.Conclusion: 0.5 % concentration of the manufactured chemo- mechanical caries removal can be used in dentinal caries removal safely with out any adverse effect on the pulp


Article
COMPUTER AIDED DESIGN OF RIVETS FOR STEAM BOILER SHELLS
تصميم برشام صفيحة المرجل البخاري باستخدام الحاسوب

Authors: Essam L. Esmail عصام العيبي اسماعيل --- Farah Kamil Abid Muslim فرح كامل عبد مسلم
Journal: Al-Qadisiyah Journal for Engineering Sciences مجلة القادسية للعلوم الهندسية ISSN: 19984456 Year: 2012 Volume: 5 Issue: 4 Pages: 377-393
Publisher: Al-Qadisiyah University جامعة القادسية

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Abstract

Most mechanical CAD software used in mechanical design involves different types of decisions. All these decisions require coordinate-geometric and descriptive data. The objective of this work is to establish software programs for designing and analyzing rivets for boiler shells as an example to use rivets in industry. In general rivets are considered as mechanical elements of wide range application.A software program using Visual Basic Version 5 with ACCESS database is used for design of rivets. When the user inters the input data to the system and depending on existing database, the software carries out a series of complex computations, after which it produces a comprehensive report that includes all engineering dimensions and efficiency.The program, designed in this research, has feasible ability to deal with data base in an easy and reliable way especially for unprofessional users. This is a database that can be updated and edited at any time to get proper results. The program can be applied also to different types of riveted joint.

معظم برامج التصميم المعان بالحاسوب للأجزاء الميكانيكية تتضمن إمكانية أتخاذ انواع مختلفه من القرارات. وكل هذه القرارات تتطلب إحداثيات للبيانات الهندسية بالإضافة إلى البيانات الوصفية. الهدف من هذا البحث هو تأسيس برامج حاسوبية لتصميم وتحليل براشيم صفيحة المرجل البخاري (boiler shell rivet) كمثال على تصميم البراشيم ، اذ من المعروف بصوره عامه أن البراشيم هي واحده من الأجزاء الميكانيكية المهمة الواسعة الاستخدام.يتضمن البحث: بناء نظام حاسوبي لتصميم برشام صفيحة المرجل البخاري حيث تم بناء هذا النموذج باستخدام برنامج بلغة الفيجوال بيسك الإصدار الخامس مع قاعدة بيانات أكسس ACCESS، فعندما يقوم المستخدم بإدخال البيانات الى النظام ، يقوم النظام بسلسلة عمليات حسابية معقدة بالاعتماد على قاعدة البيانات الموجودة في النظام ثم يقدم تقريرا مفصلاً عن جميع الابعاد الهندسية لبرشام صفيحة المرجل البخاري وكذلك كفاءته. البرنامج الذي تم تصميمه في هذا البحث له امكانية التعامل مع قواعد البيانات بشكل متين وطريقة سهلة على المستخدم بحيث تسمح لأصحاب الخبرة البسيطة من المستخدمين في العمل عليها بسهوله وهي عبارة عن قاعدة بيانات جيدة قابلة للتحديث والتعديل في اي وقت للحصول على نتائج البرنامج بطريقة سليمة. كما ويمكن تطبيق البرنامج ايضا على انواع مختلفة من الربط باستخدام البرشام.

Keywords

CAD --- Mechanical design


Article
Anticipating Mechanical Ventilation In Children With Guillain –Barre Syndrome And Improving Outcome Of The Illness

Author: Muhi K. Al-janabi* *MBChB DCH FICMS د.محي كاظم الجنابي
Journal: Journal of the Faculty of Medicine مجلة كلية الطب ISSN: 00419419 Year: 2007 Volume: 49 Issue: 2 Pages: 219-222
Publisher: Baghdad University جامعة بغداد

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Abstract

Summary:Background: Acute inflammatory demylinating polyneuropathy (Guillain-Barr'e syndrome) is the commonest cause of acute neuromuscular paralysis in most countries. The onset of symptoms in patients with GBS can either be acute or sub acute .Ventilatory failure is primarily caused by inspiratory muscles weakness although weakness of abdominal and accessory muscles of respiration, retained airway secretion leading to aspiration and atelectasis are all contributing factors. Nutritional support of critically sick children is important for metabolic maintenance and tissue repair.Methods: To identify clinical and respiratory features associated with progression to respiratory failure in children with GBS. Twenty two consecutive children with severe (Rapidly progressive) GBS admitted to the RICU in Children Welfare Teaching Hospital-Medical City –Baghdad, between July 2004-July 2006, were studied .Other 22 children with sub acute GBS who didn't receive mechanical ventilation admitted in the same period to the same hospital as a control group.Results: There is significant association between each of bulbar, autonomic neuropathies and low SiO2 at admission with severe GBS .There is significant reduction in duration of mechanical ventilation and duration of RICU stay achieved by the use of Freamine amninoacid solution as partial parenteral nutrition.Conclusion: Progression to mechanical ventilation was highly likely to occur in those patients with rapid disease progress (less than one week) bulbar dysfunction and dysautonomia, and low SiO2 at admission. Partial parenteral nutrition may reduce the duration of mechanical ventilation and RICU stay by about 3 days.Keywords: GBS; mechanical ventilation; children.


Article
NEW IJAP ADVISORS
انضمام أعضاء جدد للهيئة الاستشارية للمجلة

Author: Editorial Board
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2015 Volume: 11 Issue: 3 Pages: 8-8
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

Since September 2015, the Advisory Board of IJAP welcomes new three advisors to contain of 21 members, 7 from Iraq and 14 from foreign countries. The new advisors, Dr. Morshed Khandaker, Dr. Mohammad Hossan and Dr. Gang Xu, have accepted the invitation of IJAP Editorial Board to join the Advisory Board.


Article
The impact of different combine harvester regulations during the mechanical harvesting of forat rice variety

Author: Kamal Muhsin Ali Al-Qazzaz
Journal: Kufa Journal for Agricultural Sciences مجلة الكوفة للعلوم الزراعية ISSN: 20727798 23128186 Year: 2015 Volume: 7 Issue: 3 Pages: 186-204
Publisher: University of Kufa جامعة الكوفة

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Abstract

The research was conducted at the Mishkhab research station to study the impact of differentcombine harvester regulations on the rice losses inflected by harvester units and the totallosses for the Class Dominater harvester .The forat variety which was verified by the ministryof agriculture was used in this experiment .However , the research consist of three factorswith three levels for each factor , these are : combine field speed are 1.7, 2.3 and 3.0 km/hr,threshing cylinder speed are 800,1000and 1200 r.p.m , cylinder concave clearance are 1.25,1.5 and 2 cm , the research performed as a factorial experiment at the RCBD design withthree replications.The forat rice crop variety showed a clear response to change combine harvester regulations.These regulations are combining harvester field speed, threshing cylinder concave clearancewhich were counted as the three main factors of this research. The results observed showedthat the losses of the each combine harvester unit and the total losses were changedsignificantly as the combine harvester field speed changed. The highest total losses ratio ofcombine harvester was 7.24% at the highest field speed (3.0km/hr). However this ratiodecreased at the other two combine harvester field speeds and the reason was the combine reelindex which was at its optimal condition. This reel condition coincided the combine fieldspeed with the reel speed and the result was a reduction in the combine platform losses andthis result reflected on the combine total losses .This phenomenon was observed particularlywith this variety because it is easily shattered.The results also showed that the effect of increasing the threshing cylinder speed or reducingthe cylinder concave clearance within the range of this research was identical interim of theresults achieved .However, it was observed that no significant effect of changing these factorson the combine platform losses, while a significant in losses was noticed in the threshing andseparation units. It was also noticed that no significant effect either the threshing cylinderspeed or cylinder concave clearance on the ratio of the total losses.The results of the interactions showed that the lowest percentage of the total losses forharvesting of forat varies was 4.72 % at 1.7 km/hr combine field speed 800 r.p.m threshingcylinder speed and 2.0 cm cylinder concave clearance while the highest total losses was 8.3 %at the highest combine field speed 3 km/hr, 1000 r.p.m threshing cylinder speed and 1.25 cmcylinder concave clearance.


Article
Comparison Between Mechanical and Non Mechanical Bowel Preparation Prior To Elective Colorectal Surgery

Author: Wissam Jaffar Altaee وسام جعفر
Journal: Al-Kindy College Medical Journal مجلة كلية الطب الكندي ISSN: 18109543 Year: 2011 Volume: 7 Issue: 2 Pages: 85-90
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Bowel preparation prior to colonic surgery usually includes antibiotic therapy together with mechanical bowel preparation which may cause discomfort to the patients, prolonged hospitalization and water & electrolyte imbalance. Objective: to assess whether elective colon and rectal surgery may be safely performed without preoperative mechanical bowel preparation. Method: the study includes all patients who had elective large bowel resection at Medical City – Baghdad Teaching Hospital between Feb, 2007 to Jan, 2010. Emergency operations were not included. The patients were randomly assigned to the 2 study groups (with or without mechanical bowel preparation. Results: A total of 165 patients participated in the study, 82 with mechanical bowel preparation and 83 without. The 2 groups were similar in age, sex and type of surgical procedure. 134 patients (81.2 %) underwent surgery owing to colorectal cancer & 31 patients (18.8 %) owing to benign disease. The hospitalization period was longer in the bowel-prepared group (mean ± SD, 8.2 ± 5.1 days) as compared with the non prepared group (mean ± SD, 8.0 ± 2.7 days). However, this difference was not statistically significant. The time until the 1st bowel movement was similar between the 2 groups : a mean ± SD of 4.2 ± 1.3 days in the non prepared group as compared with a men ± SD 4.3 ± 1.1 days in the prepared group ( P = NS ). Conclusion: Our results suggest that no advantage is gained by preoperative mechanical bowel preparation in elective colorectal surgery.

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