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Article
Control Techniques of Torque Ripple Minimization for Induction Motor
تقنيات لتقليل تموج عزم الدوران للمحرك الحثي

Author: Thamir Hassan Atyia
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2018 Volume: 25 Issue: 4 Pages: 57-63
Publisher: Tikrit University جامعة تكريت

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Abstract

A Matlab-Simulink environment used to build a model of an Induction Motor (IM) to study and explore methods for minimizing the torque ripple. Various control strategies were reviewed and simulation studies were carried out for the following control methods: Direct Torque control, Direct Torque control with harmonic elimination, and Direct Torque control with Matrix convertor were the obtained results analyzed, evaluated, and compared to each other. The simulation results confirmed that Using Direct Torque Control with Harmonic elimination method was significantly minimized the torque ripple as the harmonics of the output voltage were canceled; discussions and conclusions were presented in this study.

إن وجود بيئة ماتالب-SIMULINK تستخدم لبناء نموذج لمحرك حثي )IM )لدراسة واستكشاف طرق لتقليل تموج عزم الدوران. وتم استعراض استراتيجيات مختلفة وأجريت دراسات محاكاة لطرق التحكم التالية: التحكم المباشر في عزم الدوران: التحكم المباشر في عزم الدوران مع حاذف االشارة التوافقية، والتحكم المباشر في عزم الدوران مع حاذف االشارة التوافقية مع مصفوفة محول)(AC-AC وكانت النتائج المتحصل عليها تم تحليلها وتقييمها، ومقارنتها مع بعضها البعض. أكدت نتائج المحاكاة التي تم تحقيقهاعن تقليل التموج في عزم الدوران؛ وتم عرض المناقشات واالستنتاجات واالقتراحات في هذه الدراسة.


Article
Normal faciolingual inclination of tooth crowns for Iraqi adolescent in Mosul City

Author: Nada M Al–Sayagh
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2004 Volume: 4 Issue: 2 Pages: 104-112
Publisher: Mosul University جامعة الموصل

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Abstract

The purposes of this study are to determine the faciolingual inclinations of tooth crowns in Class I normal occlusion of Iraqi adolescent in Mosul City, investigate the possible significant differences between genders, and determine the correlation of the faciolingual inclination of teeth crown with each others. The sample of this study consisted from 35 Iraqi adolescents (19 males and 16 females) aged 12–16 years selected according to certain criteria from Mosul City. Stone casts were taken for each subject, the faciolingual inclinations were made on the dental models of the subjects by using torque angle gauge. The data were analyzed with the Statistical Package for Social Sciences program and it was found that each tooth distally to the central incisor had more lingual inclination than did its neighbor. The females had more labial inclination of upper lateral incisor and more lingual inclination of the lower canine, premolars and first molar as compared with the males. Most intraarch teeth torque correlation were positive and decreased with remoteness while most interarch teeth correlation showed weak negative correlation.


Article
The Effect of Power System Stabilizers (PSS) on Synchronous Generator Damping and Synchronizing Torques
تأثير مثبت منظومة القدرة على عزم التخميد وعزم التزامن للمولد المتزامن

Author: Fadhil M. Kalaf فاضل محسن خلف
Journal: AL-MANSOUR JOURNAL مجلة المنصور ISSN: 18196489 Year: 2012 Issue: 18 Pages: 101-118
Publisher: Private Mansour college كلية المنصور الاهلية

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Abstract

The synchronizing and damping torque coefficients in the range of theelectromechanical oscillation frequencies provide a measure of thegenerators' contribution towards power system stability under smalldeviations, and may be taken as stability indices even for multi machinesystems, although their interpretation is rather complex in this case. Thispaper presents the effect of Power System Stabilizer (PSS) on thesynchronizing and damping torque coefficients for a synchronous generatorconnected to an infinite busbar through impedance; it explicitly includes theeffects of its Automatic Voltage Regulator (AVR) and of the additionalstabilizer signal derived from the rotor speed. .Results obtained were compared with the conventional (AVR) usingMATLAB 7 programming language.

أن معاملاتِ عزوم المزامنة والتخمید في مدى تردداتِ تذبذبِ خاصیةالكھرومیكانیك یُعطیانِ مقیاس لمساھمةِ المولّداتَ المتزامنة في إستقرارِیة المنظومةِالكھربائیِة في حالة الإنحرافاتِ الصغیرةِ، وقَدْ یُؤْخَذانِ كفھارس إستقرارِ حتى لأنظمةِالماكناتِ المتعددةِ، بالرغم من تعقید الموضوع في ھذه الحالةِ. یُقدّمُ ھذا البحث تأثیرَ مثبّتِعلى معاملاتِ عزوم المزامنة والتخمید لمولّد متزامن أوصلَ (PSS) النظامِ الكھربائيِإلى قضیب لانھائي خلال معاوقة كھربائیةِ. ومن ضمّنُ التأثیراتَ تأثیر منظّمِ الفولطیةوتأثیر إشارةِ المثبّتِ الإضافیةِ المأخوذة مِنْ سرعةِ الدوّار . (AVR) الآليِ(AVR) أن النَتائِج المكتسبة قُورنتْ بإستعمال منظّمِ الفولطیةِ الآليِ التقلیديِ.MATLAB وبأستخدام الُلغةَ البرمجیة


Article
CLEANING AND STERILIZATION EFFECT ON THE TORSIONAL PROPERTIES OF PROTAPER ROTARY TITANIUM COBALT (Ti-C0) ENDODONTIC INSTRUMENT
تأثير التنظيف والتعقيم على عزوم الالتواء لمادة التيتانيوم كوبالت المستخدمة في توسيع قنوات جذور الاسنان.

Author: Ibrahim H. Mukhlif ابراهيم حمد مخلف
Journal: Journal of university of Anbar for Pure science مجلة جامعة الانبار للعلوم الصرفة ISSN: ISSN: 19918941 Year: 2011 Volume: 5 Issue: 1 Pages: 37-40
Publisher: University of Anbar جامعة الانبار

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Abstract

This study was conducted to evaluate the effect of the number of cycles of cleaning using NaOCl solution of different concentration and sterilization using autoclave and dry heat oven on the torsional properties of rotary (Ti-Co) instruments. A total of forty five rotary protaper finisher instruments were divided into 3 groups: Group 1 were subjected to neither cleaning nor sterilization cycles and assigned as the control group. Group 2 and group 3 were subjected to 5 and 10 cleaning and sterilization cycles respectively, soaked within (2% and 5%) NaOCl, were sterilized with autoclave and dry heat oven. Then, all instruments were subjected to a clockwise torsional load until fracture, the torsional moment and angular deflection at fracture were calculated. The results show a significant reduction in the torsional strength after cleaning and sterilization cycles regardless the concentration of NaOCl, type and number of sterilization cycles. For the angular deflection, there was a highly significant reduction, where, the number of cycles was the most influencing factor for reduction of the angular deflection whereas, the concentration of NaOCl and the type of sterilization were show no significant influence on the angular deflection.

أجریت هذه الد ا رسة لتقییم تأثیر عدد م ا رت (دو ا رت) التنظیف باستخدام محلول القاصر بت ا ركیز مختلفة والتعقیم باستخدام جهاز التعقیمبواسطة البخار المحمي و الضغط و فرن الح ا ررة الجاف على خواص الالتواء للأدوات الدوارة المصنوعة من التیتانیوم كوبالت. تماستخدام خمسه أداة دوارة نوع (بروتیبر المتممة) وقد تم تقسیمها إلى ثلاثة مجامیع:- المجموعة الأولى :أدوات لم تعرض لأي من دو ا رت التنظیف والتعقیم وتم تحدیدها كمجموعة سیطرة.- المجموعة الثانیة والثالثة : تم تعریضهما لخمس وعشر دو ا رت ( تنظیف وتعقیم ) بالتعاقب، غم رت بمحلول القاصر بت ا ركیز ٢% و٥% بمحلول القاصر، تم تعقیمها باستخدام جهاز التعقیم بواسطة البخار المحمي و الضغط وفرن الح ا ررة الجاف. كل الأدوات تمتعریضها لأحمال التواء باتجاه عقارب الساعة حتى الكسر وقد تم احتساب قیم عزوم الالتواء والانح ا رف ال ا زوي لكل أداه بعد الكسر.أظهرت نتائج الد ا رسة تأثی ا ر ملحوظا في تقلیل قیم عزوم الالتواء بعد دو ا رت التنظیف والتعقیم بصرف النظر عن تركیز محلول القاصر ونوع التعقیم وعدد م ا رت التنظیف والتعقیم. بخصوص الانح ا رف ال ا زوي كان هناك تأثی ا ر عالیا ملحوظا في تقلیل قیم الانح ا رف ال ا زويللأدوات. حیث أن عدد م ا رت التنظیف والتعقیم كانت عاملا مؤث ا ر بینما كان تركیز محلول القاصر و نوع التعقیم ذو اثر غیر ملحوظ

Keywords

torque --- angular deflection --- Ti-Co


Article
Modeling and Dynamic Performance Analysis of PMBLDC Motor
نمذجة وتحليل الأداء الديناميكي لمحرك التيار المستمر ذو المغناطيس الدائم والخالي من الفرش الكربونية

Author: Jamal A. Mohammed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2010 Volume: 28 Issue: 20 Pages: 6091-6107
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Permanent Magnet Brushless DC (PMBLDC) motors are one of the electricaldrives that are rapidly gaining popularity, due to their high efficiency, good dynamicresponse, high mechanical power density, simplicity, cost effectiveness and lowmaintenance.In this paper, the state-space technique is presented and used for analyzing thedynamic performance of PMBLDC motor. The method is based on the formulation ofstate equations from the mathematical model of the motor and conversion of them intoa set of linear algebraic equations by the use of trapezoidal rule of integration. Thesimulation of the motor has been done using the software package Matlab.

محركات التيار المستمر ذو المغناطيس الدائم والخالية من الفرش الكربونية هي أحد المسوقات الكهربائية التي اكتسبت شعبية كبيرة بسبب كفاءتها العالية واستجابتها الديناميكية الجيدة وامتلاكها الكثافة العالية للقدرة الميكانيكية وبساطتها وفاعلية الكلفة وانخفاض صيانتها.في البحث الحالي تم تمثيل واستخدام تقنية فراغ الحالة لتحليل الأداء الديناميكي لمحرك التيار المستمر ذو المغناطيس الدائم والخالي من الفرش الكربونية. هذه الطريقة تعتمد على تشكيل معادلات الحالة من النموذج الرياضي للمحرك وتحويلها إلي مجموعة من المعادلات الجبرية الخطية باستخدام.Matlab القاعدة الرباعية للتكامل. تمتّ محاكاة المحرك الحالي باستخدام الحقيبة البرمجية


Article
Torque and Magnetic Flux Analysis Using an Advanced Dynamic Dynamometer Test Bed for Electromechanical Motors

Authors: J.M. Al-Baiaty --- N.F. Daoud --- H.G. Khayat
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2009 Volume: 5 Issue: 1 Pages: 19-26
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

This paper describes the torque and magnetic flux analysis using an advanced dynamic dynamometer test bed for electromechanical motors. Test motor was tested under different levels of continuous loads and high bandwidth complex duty cycle loads in order to provide data to characterize the nonlinear properties of electric motors. The test bed to obtain torque saturation limit data is comprised of a servo motor which serves as a dynamic load emulator, a brake, a clutch, and full sensor array for comprehensive monitoring of test variables, (including magnetic flux density sensor). The magnetic flux test was conducted to discriminate magnetic saturation from torque saturation. Given the permanent magnet motor test system designed for a desired saturation limit, it is possible to predict saturation using a properly defined dynamic duty cycle norm as a function of the operating conditions and the actuator design parameters. In this paper, the temperature effects on the magnetic properties of the permanent magnet material were the principal objectives.


Article
Electrophoretic deposition of Hydroxyapatite on tapered Ti-6Al-7Nb dental implants: Biomechanical evaluation in rabbits

Authors: Yaarob M. Salman يعرب سلمان --- Raghdaa K. Jassim رغداء جاسم --- Thair L. Al-Zubaydi ثائر الزبيدي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2011 Volume: 23 Issue: special issue Pages: 36-41
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Advances in implant design have often focussed on altering the micro-topography and chemistry ofthe implant surface. This study was done to evaluate the effect of Hydroxyapatite (HA) coating on the bond strengthbetween the bone and tapered screw-shaped Ti-6Al-7Nb dental implants.Materials and methods: Electrophoretic deposition technique (EPD) was used to obtain a uniform coating ofHydroxyapatite on the tapered Ti-6Al-7Nb screws. Structural investigations were carried out on the HA coatingsurface of the Ti.6Al.7Nb alloy using X-ray diffraction (XRD). The in vivo studies were performed by the implantation oftapered screw-shaped uncoated and coated implants in the tibia of white New Zealand rabbits. To understand thebone-implant interface, biomechanical test was carried out after 2, 6 and 18 weeks healing periods.Results: The XRD result shows that the ceramic layer consists of highly crystalline form of hydroxyapatite and thecrystalline HA belong to characteristic peaks of (211) at 2Į 31.7o with the hexagonal symmetry. Biomechanical resultshows that there was increased mechanical strength (torque value) of bone-implant interface with time, and thegreater increase in the torque value was noticed between 6 and 18 weeks. Also the result shows that the taperedimplant coated with HA have higher removal torque values than uncoated one in different time intervals.Conclusion: The electrophoretic deposition (EPD) is a good alternative coating technique for dental implant. HAcoated implants demonstrate high torque value and early healing than uncoated implants, which is very importantin early loading of the implant


Article
Evaluation of frictional forces generated by different brackets and orthodontic wires

Authors: Khulood A. Almakhzomi خلود المخزومي --- Nidhal H. Ghaib نضال حسين غايب
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: special issue 1 Pages: 126-131
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Sliding mechanics is widely used during orthodontic treatment. One of the disadvantages of thismechanics is the friction generated at the bracket/archwire interface, which may reduce the amount of desiredorthodontic movement obtained. The aim of the present in vitro study was to evaluate and compare the staticfrictional forces produced by two passive self-ligating brackets stainless-steel and hybrid and two conventionalbrackets stainless-steel and monocrystal ligated with stainless-steel ligature wire at two degrees of torque(zero andtwenty) under dry condition.Materials and method: One hundred and sixty brackets were used in this study divided into four groups each groupconsisted of forty brackets these are: Two self-ligating (stainless-steel and Hybrid) while the two conventional typesare the (stainless-steel and monocrystal).twenty of each group examined with 0.016"x0.022"archwire, ten at 0˚ torqueand ten at 20˚ torque while the other twenty of each group examined with 0.019"x0.025", ten at 0˚ torque and ten at20˚ torque.Results: There was a significant different between all groups except in case when self-ligating brackets (both types)ligated to both wires at 0˚torque there was no significant difference.Conclusions: The self- ligating brackets produce significantly lower static friction than the conventional types at bothdegrees of torque. There was no significant different between both self-ligating brackets at0˚torque while at 20˚torque the stainless- steel self –ligating produce lower static friction than the clear self-ligating type

Keywords

static --- friction --- self-ligating --- conventional --- torque


Article
The Electrophoretic Deposition of Nano Al2O3 and AgNO3 on CpTi Dental Implant (An in vitro and in vivo study)

Authors: Rsul N. Turky رسل تركي --- Raghdaa K. Jassim رغداء جاسم
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2016 Volume: 28 Issue: 1 Pages: 41-47
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Even the wide use of dental implants, still there is a proportion of implants are failed due to infection.Much considerable attention has been paid to modify the implant surface. Coating of dental implant with abiocomposite material of suitable properties can improve osseointegration. And this is the main concern of this study.The aim of present study was to evaluate the use of a biocomposite coating of dental implant with (ceramic nanoAl2O3 and metalic AgNo3) on the bond strength at bone – implant interface and tissue reaction.Materials and methods: A total number of forty-eight screws, CpTi dental implant used in this study. Half of thesescrews were coated with a biocomposite material of nano (Al2O3and AgNo3), this was done by using electrophoreticdeposition method (EFD). In invitro part of the study, analysis of the coated surface was done using: X ray diffraction(XRD), atomic force microscope (AFM), Energy Dispersive X-ray spectroscopy (EDX), Optical microscopy andScanning electron microscope (SEM). In invivo part of study, 10 white male New Zealand rabbits were used, and ascrew type of dental implant [uncoated and coated with nano (Al2O3and AgNo3)] were implanted in each tibia ofrabbit. Then biomechanical and Histological test were performed after 2 and 4 weeks healing intervals.Results: The results of biomechanical test showed a higher torque mean values of (M+SD):(14.91N.cm+2.7)and (22.5N.cm +5.31) after 2 and 4 weeks respectively. In histological examination of coated screws at 2 weeks, there isabone trabeculae occupies a base of implant bed with osteoblast andosteocyte. At 4 weeks, there is a progress inthe healing process around dental implant, and this includes: -new bone with haversian canals, osteoblast andosteocyte.Conclusion: Biocomposite coating of dental implant with Alumina and silver nitrate can be made by electrophoreticdeposition method (EPD), and a multifunctional surface has been created


Article
TORISIONAL BEHAIVORE OF REACTIVE POWDER CONCRETE T-BEAM WITH WEB OPENING
سلوك اللي للعتبات ذات شكل T وذات خرسانة المساحيق الفعالة والحاوية على فتحات في الجذع

Authors: Ali Sabah Alamli --- Hayder Abdulameer Mehdi --- Reem Hatem Ahmed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2017 Volume: 21 Issue: 3 Pages: 72-86
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Ten T section reinforced concrete beams by use Reactive Powder Concrete (RPC) beams with square and circular web perforation tested under pure torsion . The geometry and main reinforcement of all specimens are same. The main parameters taking into account in present paper are circular opening size, location of openings and number of openings. The torque caused the ultimate crack was recorded, and the angle of twist generated from these torques is calculated. Test results indicate that, torque that causes failure (ultimate) is affected by opening size, opening locations, opening numbers, the presence of web cut – outs reduces ultimate torque capacity of section, such that the increase in web opening size reduces the ultimate torque, when the web openings increase that leads to reduction in the torque capacity، the opening eccentricity makes no uniformity of shear stress distribution through web and leads to reduce the torque capacity. Then, angle of twist depends on the opening location at crack or ultimate stages, the twisted angle depends on torque magnitude because of beam span, shear modulus and geometry of T sections which are the same and the cracks start from support and then take a spiral shape around the beams up to flange so the number of cracks increases as the presence of openings.

عشر عتبات من خرسانة المساحيق الفعالة المسلحة ذات مقطع T حاوية على فتحات مربعة ودائرية فحصت تحت تأثير عزم لي صافي . الشكل و التسليح هو نفسه لكل النماذج . المتغيرات الرئيسية التي اعتمدت في هذا البحث هي حجم الفتحات الدائرية, موقع الفتحات و عدد الفتحات . عزم اللي الذي سبب التشقق النهائي تم تسجيله وكذلك زاوية اللي قد تم حسابها ايضاً. النتائج بينت أن عزم اللي الذي الفشل النهائي قد تأثر بحجم وموقع وعدد الفتحات، فوجود الفتحات في الجذع أدى الى تقليل مقاومة المقطع لعزم اللي النهائي، وكذلك زيادة حجم الفتحات يقلل من مقاومة عزم اللي, كما اظهرت زيادة الفتحات الى الحد من قدرة عزم اللي، إن الفتحات تعمل على عدم توحيد توزيع اجهادات القص خلال الجذع (WEB) ويؤدي الى التقليل من قدرة عزم اللي (الدوران) , وكذلك زاوية الألتواء تعتمد على موقع الفتحات عند مرحلة اللي الابتدائي او النهائي , تتأثر زاوية الالتواء بمقدار عزم اللي المسلط وعزم الجسائة والقصور الذاتي للمقطع وذلك لعدة اسباب منها طول العتبة ,معامل القص وشكل مقطع العتبة. إن التشققات تبدأ من المساند وتأخذ شكل حلزوني حول العتبة لتصل الى الجناح حيث تبلغ الشقوق ذروتها بوجود الفتحات.

Keywords

Torque --- cracks --- RPC --- Web Opening --- T Section.

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