research centers


Search results: Found 174

Listing 1 - 10 of 174 << page
of 18
>>
Sort by

Article
INVESTIGATION OF LOAD EFFECTS AND TEMPERATURES ON RATE OF WEAR USING BRASS AND CARBON STEEL MATERIALS.

Author: Dr. Ahmed A. Al.kafaji & Talib H. Rashid
Journal: Iraqi journal of mechanical and material engineering المجلة العراقية للهندسة الميكانيكية وهندسة المواد ISSN: 20761819 Year: 2013 Volume: 13 Issue: 3 Pages: 458-466
Publisher: Babylon University جامعة بابل

Loading...
Loading...
Abstract

The study was done to predict rates of wear which occurred as a result of friction process between a brass material and a carbon steel disc was rotated with speed equal to 675 r.p.m. The wear rates were calculated for a dwell time equal to 30 minutes for each case of applied loads of 250g, 750g and 1250g. This research investigated the effects of loads applications on the variation in temperatures which were taken place due to rubbing action at contact area that may play role in specifying the wear rates. These results have indicated the style of wear rates expressed by volume and by weight that may be a guide for the designers when using those materials at similar friction conditions

تمت الدراسة للتنبؤ بمعدلات البلى نتيجة احتكاك مادة البراص و قرص الفولاذ الكار بوني الذي يدور بسرعة 675 دورة/دقيقة . تم حساب معدلات البلى لفترة 30 دقيقة لكل حالة بعد تسليط اثقال مختلفة ( 250غم, 750 غم, 1250غم ). في هذا البحث تم التحقيق في تاثيرات الاحمال على التغير في درجات الحرارة الحاصل نتيجة الاحتكاك والذي قد يكون لها دور في تحديد معدلات البلى. و قد أشارت النتائج إلى انماط لمعدلات البلى وقد تم التعبير عنها بدلالة الحجم وكذلك بدلالة الوزن. ان هذه المؤشرات تشكل دليلا يساعد المصممين عند اختيار هذه المواد في ظروف احتكاك مشابهة.


Article
Dental Wear Its Prevalence and Patterns in Class I Malocclusion (A Comparative Study)

Author: Kasem Ahmed Abeas
Journal: Medical Journal of Babylon مجلة بابل الطبية ISSN: 1812156X 23126760 Year: 2015 Volume: 12 Issue: 3 Pages: 828-835
Publisher: Babylon University جامعة بابل

Loading...
Loading...
Abstract

Dental wear is a physiological process that occurs normally through a variety of mechanisms and age progression. It is aloss of tooth structure during masticatory forces. The study aimed to investigate patterns of tooth wear in adult with class I malocclusion (crowding) then the normal occlusion is compared with them. Our study sample consisted of 2 groups with an age range “18-25” years.The 1rstgroupwas (30 subject) with normal occlusion and the 2nd was (30 subject) with class I crowding. A modified version of the tooth wear index (TWI) was used to assess the amount of tooth wear.Tooth wear was greater statistically in incisal surfaces of central incisors of the upper arch and lateral incisors of both arches in class I malocclusion group than was in group of normal occlusion. While significant tooth loss was found in the buccal surfaces of the lower 1rst molar and the incisal surfaces of upper canines in normal occlusion than it was in crowding group. It was concluded that the irregularity of the dentition in class I malocclusion subjects lead to the differences in the pattern of tooth wear in both the normal and malocclusion groups.


Article
Tooth attrition patterns in a group of Iraqi adults sample with different classes of malocclusion (A comparative study)

Authors: Issam M. Abdullah عصام عبد الله --- Ausama A. Al- Mulla اسامة احمد الملا
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 2 Pages: 114-119
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: Tooth attrition is wearing away of tooth structure during mastication. This study investigated tooth wearpatterns in adults with different classes of malocclusion and compared them with normal occlusion.Materials and methods: The sample consisted of 363 subjects that were divided into 5 groups with an age range “18-25” years: 85 normal occlusion, 128 class I with crowding, 90 class II division 1, 30 class II division 2 and 30 class III.Dental wear was assessed by using a modified version of the tooth wear index.Results:1. The class I malocclusion group had statistically greater tooth wear in incisal surfaces of maxillary central and lateralincisors, and mandibular lateral incisors than did the normal occlusion.2. The class II division 1 group had statistically greater tooth wear in the occlusal surfaces of maxillary secondpremolars, mandibular first and second premolars. Buccal surfaces of mandibular canines, mandibular secondpremolars and mandibular first molars than did the normal occlusion.3. The class II division 2 malocclusion group had statistically greater tooth wear in labial surfaces of mandibularcentral and lateral incisors. Buccal surfaces of mandibular second premolars, mandibular first molars. Occlusalsurfaces of maxillary first and second premolars and mandibular second premolars than did normal occlusion.4. The class III malocclusion group had statistically greater tooth wear in the occlusal surfaces of maxillary first andsecond premolars than did normal occlusion.Conclusion: In conclusion subjects with normal occlusion and those with different classes of malocclusions havedifferent tooth wear patterns


Article
Automated Visual Inspection of Cutting Tool Wear
الفحص المرئي المؤتمت لبلى عدد القطع

Authors: Ali Abbar Khleif --- Ali Kareem Alwan
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2015 Volume: 33 Issue: 6 Part (A) Engineering Pages: 1442-1449
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

Nowadays, CNC machines have high importance in manufacturing factories and workshops due to its high accuracy and flexibility. Unfortunately it still cannot ensure the quality of machined products. The trend towards automation in machining has been driven by the need to maintain high product quality with improving production rate. These improvements can be possible by monitoring and control of machining process, in this research a new algorithm is introduced for the direct measurement of cutting tool wear by vision system on the basis of edge detection and morphological operations for the captured images. The results showed the efficiency of the proposed method for online monitoring of the tool condition.

في الوقت الحاضر , تحظى مكائن القطع المبرمجة باهمية كبيرة في المعامل والورش التصنيعية بسبب دقتها العالية ومرونتها لكن لسوء الحظ لا تزال هذه المكائن غير قادرة على التاكد من جودة السطوح المنتجة . الاتجاه نحو اتمتة عمليات القطع سُير للحاجة الملحة للحصول على جودة عالية للمنتجات وتحسين معدل الانتاج . هذه التحسينات تصبح ممكنة عند المراقبة والسيطرة على عملية التشغيل . في هذا البحث تم اقتراح خوارزمية جديدة للقياس المباشر لبلى عدة القطع بواسطة نظام رؤية على اساس تقنية ايجاد الحواف وعمليات المعالجة المورفولوجية للصور الرقمية الملتقطة . اضهرت النتائج المستحصلة كفاءة الخوارزمية المقترحة لمراقبة بلى العدة اثناء العمل.


Article
Computer Aided Flank Wear Measurement in End Milling Cutting Tool

Authors: Ali Abbar Khleif --- Mostafa Adel Abdullah
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 5 Part (A) Engineering Pages: 959-972
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

Flank wear width is generally recognized as the key indicator for tool life.In the experiments of this study, nine tools made of HSS and stainless steel 316L as work piecewiththreespindlespeeds(550,930 and 1100)rpm and three redial depth of cut (1.5,2 and 2.25)mm were used. The cutting tool wear was measured using optical microscope and vision system based on a proposed algorithm.Maximum and minimum percentage errors in the flank wear width were (8.250% and 0.645 %) respectively. The numerical method used was by a multiple linear and polynomial regression model and developed a polynomial model, especially to predict the flank wear using MATLAB software.Maximum and minimum percentage errors werefound (14% and 0.322 %) respectively.


Article
Investigation of the Tribological Behavior of Eutectic Al-Si Casting Alloy

Author: Riyadh Azzawi Badr
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2017 Volume: 24 Issue: 3 Pages: 42-46
Publisher: Tikrit University جامعة تكريت

Loading...
Loading...
Abstract

The effect of roughness of Al-Si alloy on the wear is investigated. Roughness average (Ra) was verified via different polishing, also was using a pin–on-disc of different loads (5, 10, 15) N, different speeds (100, 200, 300) rpm and relative humidity 74%. Different values of Ra are obtained with (3, 5 and 7) µm. Worn surface were characterized using SEM / EDX. The results show that the wear rate of Al-Si eutectic alloys increases with the roughness increase. It was noticed that the specific and wear decreases as roughness decreases. Severe wear was observed at all loads.


Article
Effect of Heat Treatments on Sliding Wear Behavior of Medium Carbon Steel
تاثير المعاملات الحرارية على سلوك البلى الانزلاقي لفولاذ متوسط الكاربون

Author: Ahlam Abdalamir Mohamed احلام عبدالامير محمد علي
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2012 Volume: 30 Issue: 13 Pages: 318-328
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

The aim of this work is to study the effect of heat treatments on the wear rate ofthe medium carbon steel which included normalizing and different quenchingmedia (air, oil, salt solution at concentration %25). Quenching Include heating toa temperature of 870Co and then rapid cooling. A Pin -on-Disc technique was usedto measure the wear rate under dry sliding conditions with applied and differentsliding times with constant sliding speed of disc (641 r.p.m) and hardness of thesteel disc (48 HRC).The results show that the wear rate increases with applied loads, and withincreasing sliding time for all heat treated specimens it was found that the hardnessvalues of the quench specimens at salt solution is higher than that of normalizedspecimens and quenched specimens in the oil.

تضمن هذا البحث دراسة تاثير المعاملات الحرارية على معدل البلى الانزلاقي لفولاذمتوسط الكاربون وهي المعادلة والتقسية باوساط تقسية مختلفة (الزيت، محلول ملحيبتركيز 25 %). وتضمنت التقسية التسخين عند درجة حرارة ( 870 ) م° ثم التبريد السريع لكللقياس معدل البلى (Pin – on Disc) العينات المقساة ، وقد استخدمت تقنية المسمار على القرصتحت ظروف الانزلاق الجاف وعند تسليط احمال مختلفة وتثبيت زمن الانزلاق ، وفترات انزلاقHRC ) مختلفة مع تثبيت سرعة الدورانية للقرص( 641 ) دورة/دقيقة وصلادة القرص الفولاذي48 ). وقد اظهرت النتائج ان معدل البلى يزداد بزيادة الحمل المسلط والفترة الزمنية للانزلاقلجميع العينات المعاملة حراريا واظهرت النتائج ان قيم الصلادة للعينات المقساة بالمحلول الملحياعلى من العينات المقساة بالزيت والعينات المعاملة بالمعادلة.


Article
Distribution of tooth wear among institutionalized residents (50-89 years old) in Baghdad city Iraq (Cross-sectional study)

Authors: Mohammed G. Al-Azawi محمد العزاوي --- Sulafa K. El-Samarrai سلافة خالد السامرائي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 1 Pages: 180-183
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: Tooth wear is one of the most common problems in the older dentate population which results from theinteraction of three processes (attrition, abrasion and erosion) and it affects all societies, different age groups, and allcultures. This study was achieved to evaluate the prevalence and distribution of tooth wear among institutionalizedresidents in Baghdad city Iraq.Subjects and Methods: This survey was accomplished on four private and one governmental institution in Baghdadcity. One-hundred twenty three (61 males, 62 females) aged 50-89 years were participated in this study. The diagnosisand recording of tooth wear were according to criteria of Smith and Knight.Results: The prevalence of tooth wear was 100% with a mean (30.79± 19.39) and median (28). The highest grade oftooth wear recorded was grade 2 (56.9%), followed by grade 3 (26%), grade 4 (17.1%). There was no statisticallysignificant difference of total tooth wear among age groups (P>0.05), astatistically significantdifference was seenregarding the severity of tooth wear among different age groups; for grade 2 and grade 4 (P <0.05), while astatistically highly significant difference recorded for both grade 1 and grade 3. A statistically highly significantdifference of the total tooth wear was recorded between the total males and females (P <0.01).Conclusion: The occurrence of tooth wear among those subjects was high thus they need oral health policy makersfor promotion, prevention and restorative care


Article
Estimation of Wear Depth as an Approach to Predict Tool Service Life in Cold Forming Process

Authors: Lutfi Y. Zaidan لطفي يوسف زيدان --- Akram Mahdi Abd اكرم مهدي عبد --- Mohsin A. AlShammari محسن الشمري
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2019 Volume: 12 Issue: 2 Pages: 13-34
Publisher: Diyala University جامعة ديالى

Loading...
Loading...
Abstract

Wear phenomenon is considered as a predominant parameter in the forming processes causing the shorten tool life which in turn increases the production costs. In this study, wear depth of tool components for multi-stages of metal shell of spark plug (MSSP) manufacturing was analyzed using Archard's model with FE simulation software. The 3D geometry models were built using SolidWorks software then the models files were exported to Simufact forming software to do the settings of preprocess and FE analysis. The cylinder compression test and ring compression test were executed to get the flow stress and frictional factor respectively. Product parts dimensions, forging loads, effective stress, relative sliding velocity and contact pressure were solved and discussed. Subsequently to verify the analysis acceptance, the actual product parts measurements which obtained by coordinate measuring machine (CMM), were compared with the simulation results. It was found that the deviations of actual MSSP geometry dimensions less than (4%). Also verification is performed to forging loads at each stage which gives a good agreement between actual and FE simulation results. Finally, the wear depth of tool components were calculated for each stage using the FE software. Based on the results of wear depth from simulation and tolerance rages of actual product parts, tool service lives were predicted to find the productivities for each tool component. The results of FE simulation were compared with the CMM measurements for known productivities tool components from actual production line, which gives a good accuracy and acceptable agreement.

Keywords

Wear --- Cold Forming


Article
Effect of Al2O3 and Fly Ash Addition on Mechanical, Wear and Corrosion Properties of Al-Mg-Si Base Alloy

Author: Waleed T. Rashid وليد تركي راشد
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2019 Volume: 12 Issue: 2 Pages: 76-82
Publisher: Diyala University جامعة ديالى

Loading...
Loading...
Abstract

The aim of this study is to studding the effect of addition of alumina and fly ash with the particles size 106μm and different weight rations (2:2, 2:4, 4:2) to aluminium- magnesium-silicon alloy on microstructure, mechanical properties, corrosion resistance, and wear. The vortex technique was used to prepare the composite material. The microscopic structure was also examined using optical microscopy and mechanical tests (hardness, tensile strength, yield strength and elongation) and wear test. The results showed that the composite material the containing (2% fly ash and 4% alumina) had the highest tensile strength (119 Mpa), yield strength (76 Mpa) and hardness (89 kg mm2), while it has the lowest ductility (5.3%). It was also found to have the lowest wear rate (1.8* 10-6gm cm) and the highest corrosion resistance.

Keywords

fly ash --- wear --- corrosion

Listing 1 - 10 of 174 << page
of 18
>>
Sort by
Narrow your search

Resource type

article (174)


Language

English (130)

Arabic (27)

Arabic and English (17)


Year
From To Submit

2019 (12)

2018 (24)

2017 (13)

2016 (13)

2015 (21)

More...