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Article
Effect of maximal exercise on the electrophysiological evaluation of leg muscles in young healthy males

Authors: Asmaa’ K. Hamod اسماء حمود --- Shakir M. Sulaiman شاكر سليمان --- Istabrak M. Salih استبرق صلاح
Journal: Journal of the Faculty of Medicine مجلة كلية الطب ISSN: 00419419 / 24108057 Year: 2010 Volume: 52 Issue: 1 Pages: 101-104
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Bicycling is a type of aerobic exercise that it is beneficial for the health of cardiovascular, pulmonary, and musculoskeletal systems .In this study, utilization of some of electrophysiological tests is to assess changes , from the functional point of view, in the peripheral nerves & their muscles that occur in relation to maximal exercise. patients & methods: 100 young healthy males , age (18-35) years old, were collected during the period from 1st of April to 1st of October 2008 at the department of neurophysiology in the Ibn Sinna teaching hospital , Mosul city. They underwent electroneurographic assessment of common peroneal & tibial nerves, in addition to electromyographic assessment of Tibialis Anterior & Gastrocnemius muscles before & after exercise challenge test on bicycle ergometer.Results: In this study, there is a higher value regarding compound motor action potential amplitudes & motor conduction velocity of both nerves, with increase in the values of motor unit potential amplitudes & interference pattern of both muscles post exercise in comparison to the pre exercise. In addition, there is positive correlation between MUP amplitude of Gastrocnemius muscle & tibial nerve. Conclusion : the results indicates that within this age group the exercise challenge test leads to increase in the force produced with no signs of muscular fatigue electrophysiologically . Keywords: Electromyography, cycling exercise, muscle fatigue.


Article
FATIGUE ANALYSIS OF CONNECTING ROD OF INTERNAL COMBUSTION ENGINE MADE FROM ALUMINUM ALLOY – A COMPARISON WITH STEEL AND TITANIUM ALLOY MATERIALS
تحليل الكلال لذراع التوصيل في محرك الإحتراق الداخلي المصنوع من سبيكة الألمنيوم – مقارنة مع الذراع المصنوع من الفولاذ وسبيكة التيتانيوم

Author: Samir Hashem Ameen سمير هاشم أمين
Journal: AL-TAQANI مجلة التقني ISSN: 1818653X Year: 2014 Volume: 27 Issue: 4 Pages: E82-E102
Publisher: Foundation of technical education هيئة التعليم التقني

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Abstract

The internal combustion engine is consist of three main components, the Piston, the Connecting Rod, and the Crankshaft. Connecting rods can be manufactured from many different materials and with many design shapes, each type of connecting rod is designed according to the type of engine fuel ( diesel or petrol ). During manufacturing an engine it is important to choose the correct connecting rod. Information about fatigue analysis was needed for connecting rod to properly decide which one is optimum for there engine according to safety and life, by using numerical technique of Finite Element method ( ANSYS ) Package. Higher safety factor is achieved by using aluminium alloy rather than titanium alloy and steel materials with about 32.1 % and 35.6 % percentage increment respectively. Aluminium connecting rod has life reached higher than both mention materials about 99 %.

ان محركات الاحتراق الداخلي تتكون من ثلاث اجزاء رئيسية هي المكبس وذراع التوصيل والمحور الدوار. يمكن تصنيع ذراع التوصيل من معادن وتصاميم مختلفة , وكل نوع من اذرع التوصيل له استخدام حسب طبيعة وقود المحرك ( كاز او بنزين ) . من المهم عند تصميم المحرك اختيار ذراع التوصيل المناسب , في حين ان من يتخذ مثل هكذا قرار ينبغي ان يكون مسلحا بالمعلومات المطلوبة لتحليل الكلال لذراع التوصيل لغرض اخذ الاختيار الافضل بالاعتماد على الامان والعمر الاكبر لذراع التوصيل في المحرك بواسطة استخدام التحليل العددي لطريقة العناصر المحددة في برنامج ANSYS. اعلى معامل امان تم استنتاجه من البحث هو من سبيكة الالمنيوم بمعدل زيادة مئوية مقدارها 32.1 % و 35.6 % عن سبيكة التيتانيوم والفولاذ على التوالي. يزيد عمر ذراع التوصيل المصنوع من سبيكة الالمنيوم عن بقية المعادن المستخدمة بنسبة مئوية تصل الى 99 %.

Keywords

Connecting rod --- Fatigue --- Life --- ANSYS.


Article
Fatigue of Binary Blend Composite Materials

Author: Ekhlas Edan Kader
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2018 Volume: 21 Issue: 2 Pages: 195-198
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Due to their very good mechanical properties of composite materials which led to a huge increase in its application in a lot of fields.Epoxy/ PS(polysulfide) composite materials behavior in fatigue was reported. different weight fraction of PS (2%,4% and6%) were studied .Surface roughness properties of the blended composites were found for all weight fraction of PS and their fatigue properties are studied .Fatigue test was carried with rotating bending method. The loading in the test was sinusoidal wave type. The loading wave ratio is R = -1 and the frequency of loading is applied to avoid temperature rise with a frequency equal to 5Hz. Fatigue strength ,fatigue life and fatigue limit of the tested composites from standard curves are calculated. The addition of PS resulted in an enhancement in the fatigue values and cause the surface roughness to decrease at a considerable rate, the blend hardness is reduced considering shore A test.


Article
STUDY THE MICROWAVE ENERGY EFFECTS ON MECHANICAL PROPERTIES AND ESTIMATED FATIGUE LIFE OF AA7075-T6

Authors: Ahmed Adnan AL-Qaisy --- Najmuldeen Yousif Mahmood --- Rasha Mohammed Hussein
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 6 Pages: 114-124
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This study is concerned with the effect of microwave heat treatment of AA7075-T6 on the mechanical properties and fatigue life. Specimens were divided into four groups, firstly, specimens were subjected for 60 min. of microwave heat as a dry, secondly, specimens were subjected for 30 min. of microwave heat as a dry, thirdly, specimens were subjected for 60 min. of microwave heat as a wet, and fourthly, specimens were subjected for 30 min. of microwave heat as a wet condition. Then, it is compared with original alloy (AA7075-T6). The mechanical tests that used in this research are tensile, hardness, surface roughness and fatigue. It is found that hardness of dry specimens is higher than wet specimens, and hardness of dry condition for 60 min. has higher enhancement (15%) as compared with original alloy. Hardness is increased with increasing of time inside the microwave. However, tensile strength of wet conditions has higher than dry conditions; also, tensile strength is increased with decreasing of time inside microwave furnace. Ultimate and yield strength of wet condition for 30 min. have 55% and 99% respectively, enhancement as compared with AA7075-T6. Surface roughness parameter (Ra) of dry conditions has higher than wet conditions and the decreases as decreasing of time inside microwave furnace. Fatigue strength results showed that decreasing as compared with original alloy.


Article
Comparison In Anaerobic Ability and Fatigue Indicator In Runners of 400m, 800m, and 1500m
مقارنة في القدرة اللاهوائية ومؤشر التعب بين عدائي فعاليات 400 متر و800 متر و1500 متر للمتقدمين

Authors: احمد عبد الغني طه الدباغ --- حنان مراد مرزوك
Journal: journal of physical education مجلة التربية الرياضية ISSN: 20736452 Year: 2017 Volume: 29 Issue: 4 Pages: 27-41
Publisher: Baghdad University جامعة بغداد

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Abstract

The research aimed at identifying the differences in anaerobic ability and fatigue indicator between 400m, 800m and 1500m runners. The research hypothesized significant differences between 400m, 800m and 1500m runners in anaerobic ability and fatigue indicator. The researcher used the descriptive method. The subjects were (8) 400m runners, (8) 800m runners, and (7) 1500m runners. Many tests were conducted the data was collected and treated using proper statistical operations. The researcher concluded that the decrease in anaerobic ability level with the increase of distance and running speed was more in 400m runners with great difference between 400m, 800m and 1500 runners. The rise in fatigue indicator along with distance and was more in 1500m runners. Finally the researchers recommended training adaptation in order for development to happen, developing anaerobic abilities for all middle distance runners for better achievements, making similar studies on other age groups and finally using precise tests for identifying the level of players and specifying their weaknesses.

اجريت العديد من الدراسات حول تحديد نسبة المساهمة الهوائية واللاهوائية اثناء ركض المسافات القصيرة والمتوسطة والطويلة لكنها جميعها اختلفت في التحديد الدقيق لهذه المساهمات وذلك لاختلاف مجتمع العينة وطريقة القياس ومستوى العينة وجنس العينة ولذلك رأت الباحثة الى اجراء دراسة لتحديد هذه المساهمات وبالذات المساهمة اللاهوائية لدى عدائي النخبة لمسافات 400 و800 و1500 متر على مستوى العراق وكذلك للحد في تداخل التدريب والمشاركات بين السباقات الثلاثة.ويهدف البحث الى التعرف على ما يأتي:•التعرف على الفروق في القدرة اللاهوائية ومؤشر التعب بين عدائي 400متر و800 متر و1500 متر. وللتحقق من أهداف البحث افترضت الباحثان الفرضيات الآتية:•وجود فروق معنوية بين عدائي400 متر و800 متر وعدائي 1500 متر في القدرة اللاهوائية ومؤشر التعب وقد استخدم الباحثان المنهج الوصفي لملاءمته وطبيعة البحث، وتم تنفيذ التجربة على نخبة من عدائي 400 متر والبالغ عددهم (8) وعدائي 800 متر وعددهم (8) وعدائي 1500 متر وعددهم (7) وتم اجراء اختيار (Rast) لقياس القدرة اللاهوائية ومؤشر التعب وتحديد نسبة اللاكتات في الدم عن طريق اخذ عينة من الدم بعد الجهد ب(5) دقائق.واستخدم الباحثان الوسائل الاحصائية الاتية (الوسط الحسابي , الانحراف المعياري , تحليل التباين , اختبار دنكن).وتوصل الباحثان الى الاستنتاجات الآتية:•انخفاض معدل القدرة اللاهوائية مع زيادة طول المسافة وارتفاع سرعة الركض وكان اعلى معدل للقدرة لدى عدائي 400 متر. مع وجود فروف بين عدائي 400متر و800 متر وعدائي 1500 متر.•ارتفاع مؤشر التعب مع زيادة طول المسافة وكان اعلى مؤشر لدى عدائي 1500 متر مما يدل على هبوط كبير بالقدرة اللاهوائية للعدائين. مع وجود فروف بين عدائي 400متر و800 متر وعدائي 1500 متر.واوصى الباحثان بمجموعة من التوصيات أهمها مايأتي:•ان يراعي المدرب ان أي تغير في المتغيرات أعلاه لدى العداء من شأنه ان يحدث تغيرا في الإنجاز وفق الفعالية التخصصية للركض.•ان يراعي المدرب التكيفات التدريبية اللازمة لا حداث تطور في الفعالية التخصصية.•تطوير القدرة اللاهوائية لدى جميع عدائي المسافات المتوسطة للوصول الى انجازات افضل.•ادراج تمرينات القدرة اللاهوائية الى البرامج التدريبية لعدائي 1500 متر من اجل تطوير تحمل السرعة لديهم •اجراء دراسات مشابهة على الفئات الاخرى.•عدم اشراك الاعبين في اكثر من فعالية والتخصص قدر الامكان.•استخدام الاختبارات الدقيقة لمعرفة مستوى اللاعبين وتحديد نقاط ضعفهم.


Article
Study of Fatigue Fractography of Mild Steel Used in Automotive Industry
دراسة مقطع كسر الكلال للفولاذ المطاوع المستخدم في صناعة السيارات

Author: Ahmed Ameed Zainulabdeen احمد عميد زين العابدين
Journal: Al-Khwarizmi Engineering Journal مجلة الخوارزمي الهندسية ISSN: 18181171 23120789 Year: 2019 Volume: 15 Issue: 1 Pages: 82-88
Publisher: Baghdad University جامعة بغداد

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Abstract

Fatigue failure is almost considered as the predominant problem affecting automotive parts under dynamic loading condition. Thus, more understanding of crack behavior during fatigue can strongly help in finding the proper mechanism to avoid the final fracture and extent the service life of components. The main goal of this paper is to study the fracture behavior of low carbon steel which is used mostly in automotive industry. For this purpose, the fractography of samples subjected to high and low stress levels in fatigue test then was evaluated and analyzed. Hardness and tensile tests were carried out to determine the properties of used steel. Also, the samples were characterized by microstructure test and XRD analysis to examine the constitute phases. The fatigue test (S-N curve) was done at stress ratio (R= -1), and the fracture examination was perform using Scanning Electron Microscope (SEM). The results of microstructure and XRD analysis were indicating that the Ferrite and a little amount of pearlite are the dominant phases of this steel. Whereas, the fractography observations reveal that the void coalescence ductile fracture is the main failure mode in samples with high stress level, while the ductile fracture (void coalescence) with Transgranular Cleavage fracture was noticed in low stress fatigue mode for this alloy.

يعد فشل الكلال من أخطر المشاكلات الشائعة المؤثرة على أجزاء السيارات المعرضة لأحمال دورانية. لهذا فان فهم سلوك الشقوق اثناء حدوث الكلال يساعد على تجنب حدوث الفشل النهائي للجزء اثناء الخدمة واطالة عمره. ان الهدف الأساس للبحث هو دراسة سلوك الكسر للفولاذ الواطئ الكربون والمستخدم في صناعة السيارات. لهذا السبب، تم دراسة مقطع الكسر للكلال عند احمال كلال واطئة وعالية لتقويم الأجزاء وتحليلها. كما تم اجراء اختبارات الصلادة والشد لتحديد خواص الفولاذ المستخدم. كذلك، تم توصيف المادة عن طريق دراسة البنية المجهرية ودراسة حيود الاشعة السينية لتفحص الاطوار والمكونات للسبيكة. ان اختبار الكلال (الاجهاد-عدد الدورات) تم اجراءه عند نسبة اجهاد (R=-1)، وتم دراسة مقطع الكسر باستخدام المجهر الالكتروني الماسح (SEM). اشارت نتائج الفحص المجهرية والاشعة السينية بان الطور السائد لهذا النوع من الفولاذ هو الفرايت مع نسبة قليلة من البيرلايت، بينما اظهر مقطع الكسر تكون كسر مطيلي بالتحام الفجوات حيث ان هذا هو الأسلوب عند اجهادات عالية، بينما أظهرت النتائج عند اجهادات كلال واطئة تكون الكسر الانقسامي تكون الكسر المطيلي الناتج عن التحام الفجوات لهذه السبيكة.

Keywords

Automotive --- fatigue --- fracture --- mild steel.


Article
Factors associated with fatigue in patients attending a family medicine health center in Erbil city
العوامل المرتبطة بالإرهاق لدى مرضى مركز صحة طب الأسرة في مدينة أربيل

Author: Jwan Muhammad Sabir
Journal: Zanco Journal of Medical Sciences مجلة زانكو للعلوم الطبية ISSN: 19955588/19955596 Year: 2013 Volume: 17 Issue: 1 Pages: 337-343
Publisher: Hawler Medical Univeristy جامعة هولير الطبية

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Abstract

Background and objective: Fatigue, is a common presenting symptom in primary care which negatively impacts work performance, family life, and social relationships. The aim of this study is to determine the causes of fatigue and to explore the relationship between fatigue and physical, mental, social and demographic factors among patients with special reference to gender. Methods: A cross sectional study was carried out at the Brayati Family Medicine Center in Erbil city from 1st of July to the 31st of October 2011. We studied 320 patients of both genders attending the center for various reason complaining from fatigue. Formal consent was obtained. Demographic data in addition to two questionnaires were completed, Lowa fatigue scale and Hospital Anxiety and Depression Scale. Results: 86 males (26.88%) and 234 females (73.12%). The age of the subjects varied from 16-74 years .The mean age was 29.2 years, 39.69% were in the age range 30-44 years. 58.12% were illiterate or read and write only; 65.63% were married and 57.19% reported their economic level as medium. 38.44% were fatigued according to lowa fatigue scale. Higher level was detected among older age group, singles, and low economic and minimum educational status (51.16%, 45.31%, 41.80%, 41.18 and 42.57% respectively). Depression was significantly associated with fatigue, 70% of patients who were depressed complained from fatigue. Findings indicated that, in addition to increasing anxiety among the study sample, higher levels of fatigue were detected in 61.36% of them. Conclusion: Fatigue as a symptom is very common both in community and health care settings but remains medically unexplained. The most important confounders in our studied population were depression and anxiety.


Article
Residual Stress effect on Fatigue Behavior of 2024- Aluminum alloy

Authors: Riyadh A. Al-Taie --- Farag Mahel Mohammed --- Ahmed N.Al-khazraji
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2011 Volume: 29 Issue: 3 Pages: 567-578
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In the present work the effect of residual stress on the fatigue behavior of2024 Aluminum alloy was studied experimentally and numerically usingfinite element method with aid of ANSYS-11 software. All the testspecimens treated by annealing before any process to remove the internalstresses due to cold work. Residual stresses were imparted to the fatigue testsspecimens by heat treatment, pre-strain and welding. X-Ray diffraction wasused to measure the residual stress.The heat treatment; done on the test specimens with different temperature of(420, 450, 480, and 510) oC. After heat treatment; alloy mechanical propertieswere improved. For the heat treated specimens as the temperature increasedthe compressive residual stress increased to (27.06, 41.43, 72.8 and 85.6)MPa. That leads to increase the endurance fatigue limit by (32.93%, 40.48%,50.68% and 61.03%) respectively than other alloy as received. While in prestrain groups; the test specimens loaded to (265, 290, 315 and 340) MPa by atension test machine. As the applied load series were increased thecompressive residual stress increased to (16.51, 25.62, 51.54 and 62.44) MPawhich improve the endurance fatigue limit by (7.68%, 16.19%, 24.98%, and46.45%), respectively. An electrical arc and metal inert gas were used inwelding series to weld the test specimens, that present a tensile residual stressof (76.93 and 72.66) MPa, which reduces the endurance fatigue limit by(23.45% and 16.08%), respectively. The numerical results present fatiguebehavior, deflection and stress at any load, and show a reasonable agreementresults with an experimental one.


Article
Seismic Response Damage of Nuclear Tower
اضرار الاستجابة الزلزالية لبرج نووي

Author: Kadhim Karim Mohsen
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2012 Volume: 30 Issue: 6 Pages: 1029-1047
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The seismic response of the nuclear tower is analyzed by investigating the frequency response during the main recorded events. The dynamic characteristics of the nuclear tower under seismic response with higher intensity are pointed out the dominant seismic time history components determines the response characteristics of the tower. The nuclear tower coupled with the seismic loadings will amplify the damages tothe structure. These results are consistent with field observations after major seismic response, this explains the symmetry of the nuclear tower damage during seismic response. Seismic resistance measures, such as viscous damping or energy dissipation, dynamic properties and nuclear tower vibration elements will help to increase theaccuracy of the life model. In this paper, improvement in using computing program and mathematical algorithms will increase both the accuracy and confidence of the results. The contact problem of the nuclear tower structure is another direction for a detailed understanding the mechanism of the nuclear tower structure interaction, such as mode shapes, eigenvalues/vectors, deformation, propagation and non-propagation of cracks, and the stresses slip of the foundation caused by random seismic loading that can lead to damage. This study is helpful for designing new seismic resistant nuclear towers structures to reduce damage.


Article
Experimental Study on the Effect of Temperature on the Fatigue Endurance Limit of Two AL Alloys
دراسة عملیة لبیان تأثیر درجة الحرارة على حد الكلال لسبیكتین من الالمنیوم

Author: Sa’ad Abbas Al-Saraf
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2012 Volume: 30 Issue: 6 Pages: 1048-1057
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this work , an experimental study to obtain the fatigue endurance limit for two aluminum alloy , 2024 and 5052 , were carried out at stress ratio R=-1 and rotary bending tests . The fatigue tests were performed at RT, 100 °C, 200 °C and 300 °C in order to establish the S–N curve equations. The fatigue endurance limits for both alloys at different temperature conditions were calculated at 107 cyclesfrom the empirical S-N curve equations. It was found that the fatigue endurance limit decrease with increasing the temperature. Also the reduction percentage in fatigue endurance limit for 5052 Al. alloy was higher than that of 2024 Al. alloy.

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