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Article
IMPROVEMENT HARDNESS AND MICROHARDNESS OF LOW ALLOY STELL BY USING MOLTEN METAL

Author: Ali adwon H.
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2015 Volume: 8 Issue: 4 Pages: 686-691
Publisher: Diyala University جامعة ديالى

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Abstract

We examined and study the characteristics properties of bainitic low alloy steel (30crmov9) obtained by used molten copper Instead what is customary in this process using molten salts .X-ray diffractometry (XRD)and optical microscopy (OM)were used to characterized their crystal structures ,microstructure and micro hardness.


Article
The Measurement of Surface Hardness of Mineral Trioxide Aggregate Material (MTA) using Two Techniques of Condensation.

Author: Maha A. Al.Murad
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2008 Volume: 8 Issue: 12 Pages: 266-269
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: This in vitro study was conducted to exam the effect of condensation technique on surface hardness of MTA. Materials and Methods: In this study, 20 acrylic blocks were used. In each block a cubic shape cavity 4 mm in width and 4 mm in depth was prepared. The first group which involve ten samples were filled with MTA using hand condensation method. The other ten samples were filled with MTA using hand method followed by ultrasonic activation for one second after each increment.All sample after setting were prepare for Vickers Hardness Test. The first group subjected to a loadstarted from 0.5 Kg and show fatigue at 1 kg using the Vickers Hardness Machine. The second groupsubjected to a load started from 0.5 Kg and increased the load until showed fatigue of the material at 3 Kg using the Vickers Hardness Machine. All the samples were examined using stereo microscope themagnification power about 200x to perform hardness number. Results: Samples condensed with hand method followed by ultrasonic condensation showed more surface hardness than samples condensed with hand method only. There was highly significant difference between samples. Conclusions: Because OF use MTA as pulp capping is import to use Ultrasonic condensation for placement of MTA.

Keywords

Surface hardness --- condensation --- MTA


Article
Influence of Ausforming Treatment of 0.4wt%C Steel Modified With Nb On The Microstructure And Hardness Properties
تأثير المعاملة (Ausforming) على التركيب ألمجهري والصلادة لصلب wtC 0.4% مضافاً إليه عنصر النيوبيوم

Author: Hiam Razzak kadhum
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2012 Volume: 19 Issue: 3 Pages: 19-25
Publisher: Tikrit University جامعة تكريت

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Abstract

In the present work the relationship between the microstructure and the hardness of the Steel both with and without an addition of niobium was studied. Investigation by direct observation using optical microscopy was carried out.The purpose of this work was to analyze the effects of the low thermomechanical treatment of ausforming on the final microstructure and hardness of steel and of the same steel modified with niobium.It was found that the deformation during low thermomechamical treatment of ausforming introduces changes in the microstructure, such as carbide precipitation, which affect the hardness of the steel.The results show that the mechanical properties of the ausformed Steel depend on the deformation temperature, amount of deformation. The addition of niobium lead to change in the hardness of the Steels investigated.


Article
The Surface Hardness Measurement of Stone and Improved Die Stone After the Addition of a Mixture of Chemical Additives with Different Proportion

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Abstract

Background: Incorporation of chemical additives has long been a technique used to improve properties of the gypsum products. The purpose of this work was to study the effects of adding a combination of gum Arabic and calcium hydroxide to a type III dental stone and type IV improved die stone with different proportion. The effect on water/powder ratio, and surface hardness was determined.Material and method: Both material stone and die stone were blended with two proportion of additives so that each material was mixed twice but with different proportion of gum Arabic (0.1% and 0.2%) and calcium hydroxide (0.5 % and 0.3%). Data for hardness were subjected to two-way analysis of variance.Results: The results revealed that the chemical additives were reduced the water requirements of gypsum products so that the reduction of water lead to increase the density of mixture that sets harder. For type III dental stone the additives significantly improved the surface hardness, while for type IV improved die stone the surface hardness was not enhanced except it was designed to be mixed at low water/powder ratio, and in some instances a reduction in hardness was observed, especially at the most reduced water / powder ratio (0.18)


Article
Evaluation of propolis to modify soft denture lining materials, part I

Authors: Hamza S. AL-neema --- Bassima A. Abdullah --- Ammar K. AL-Nori
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2011 Volume: 11 Issue: SpIss Pages: S113-S123
Publisher: Mosul University جامعة الموصل

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Abstract

Aims to evaluate some properties of temporary soft liner (Bony plus) and permanent soft liner (vertex) before and after adding propolis extracts to it. Materials and methods ethanolic extracts of propolis(ethanolic extract of propolis) was added to temporary soft liner (Bony plus), and glycolic extract of propolis(glycolic extract of propolis) was added to permanent soft liner (vertex), then the volumetric dimensional changes, hardness, water absorption and solubility were evaluate, the total samples were (128). Results showed the presence of significant diffrence in the Hardness, Water absorption and Solubility of the modified soft liners (After adding propolis to it), and there was no significant diffrence in the volume of the soft liners before and after adding propolis.Conclusions the volumetric changes of modified and control group of permanent soft liner (vertex) was no significantly different, The modification type (for both permanent and temporary) of soft liner was significantly softer than the control group along the period of storage (1 month) and the modification type (for both permanent and temporary) of soft liner was significantly have more water absorption and solubility than the control group along the period of storage (1 month)

Keywords

Propolis --- soft liner --- hardness


Article
Hardness Removal from Drinking Water

Authors: Ahmed A. M. Ali --- Nawar O. A. Nasser
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2006 Volume: 12 Issue: 2 Pages: 405-413
Publisher: Baghdad University جامعة بغداد

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Abstract

This study included three trials that were made during December 2003 by using lime, of 98% w/w calcium hydroxide to find the relation between lime doses to be added and the hardness removed .The trials were performed by adding various doses of lime and measuring the hardness, electrical conductivity and pH in water produce by three plants, Nissan in the north of Baghdad, Al-Karama and Al-Wathba water treatment plant in Baghdad center. The objective of this study is to find the optimum lime dose that gives the minimum hardness content.The results indicate a non linear relation between lime dose added and the hardness removed . The results represented a 36% removal in hardness when using an optimum dose of lime 200 ppm in Nissan water treatment plant, while a percentage removal of 34% was obtained in both Al-Karama and Wathba water treatment plants with 300 ppm dose of lime.The low percentage removal indicates the presence of non-carbonate hardness which could not be removed by lime alone.

تضمنت هذه الدر اسه ثلاث محاولات أجريت خلال كانون الأول 2003باستخدام هيدروكسيد الكالسيوم 98% نسبه وزنيه لإيجاد العلاقة بين جرعة هيدروكسيد الكالسيوم وإزالة العسرة ,المحاولات تمت بإضافة جرع مختلفة من هيدروكسيد الكالسيوم وقياس العسرة والتوصيل الكهربائي وقوة أيون الهيدروجين للماء المسحوب من ثلاث محطات لتصفية ماء الشرب وهي مشروع نيسان شمال مدينة بغداد ,مشروع الكرامة ومشروع الوثبة مركز مدينة بغداد ,الهدف من هذه الدر اسه هو إيجاد الجرعة القصوى من هيدروكسيد الكالسيوم التي تعطي اقل تركيز للعسره. النتائج أظهرت أن هناك علاقة لا خطيه بين جرع هيدروكسيد الكالسيوم المضافة والعسره المزالة ,النتائج تمثلت بإزالة 36% من العسره عند إضافة أقصى جرعه من هيدروكسيد الكالسيوم 200 ملغملتر في مشروع نيسان بينما نسبة أزاله 34% تم الحصول عليها في مشروعي الكرامة والوثبة لجرع 300 ملغملتر النسبة القليلة للازاله أشارت إلى وجود عسره لا كاربونيه والتي لا يمكن أزالتها باستخدام هيدروكسيد الكالسيوم لوحده


Article
A study of the Hardness and Wear Rate of Elastomer Composites Reinforced by Al2O3 and SiO2 Particles
دراسة الصلادة و معدل البلى لمتراكب مطاطي مقوى بدقائق من SiO3 و 2 Al2O

Authors: Jawad K.Oleiwi --- Mohammed S. Hamza --- Mayyadah Sh. Abed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2009 Volume: 27 Issue: 7 Pages: 1422-1434
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

This research deals with the study the effect of adding the silica particles andalumina particles separately with different ratio (5, 10, 15, 20, and 25 pphr) on thehardness and wear rate of natural rubber NR and styrene butadiene rubber SBR. Theresults show that the hardness increases with the increase the loading level of reinforcingparticles, while the wear rate decreases with the increase the loading level of thereinforcing particles. The largest value of the hardness and the lowest value of the wearrate were for styrene butadiene reinforced with 25 pphr of silica as compared withnatural rubber. Also the reinforcing by SiO2 increases the hardness and decreases thewear rate more than of Al2O3.The results indicated that the hardness and the wear rate for SBR and NRreinforced by SiO2 and Al2O3 at (25 pphr) illustrated in the following table:

تناول هذا البحث دراسة تاثير اضافة دقائق السليكا و الالومين ا بصورة منفصلة و بنسب مختلفة5) على الصلادة و معدل البلى للمطاط الطبيعي و مطاط الستايرين - , 10, 15, 20, and 25 pphr)بيوتادايين. بينت النتائج بان الصلادة تزداد مع زيادة نسب اضافة مادة التقوية , بينما معدل البلى يقل معزيادة نسب اضافة مادة التقوية . حيث ان اعلى قيم للصلادة و اقل معدل بلى تم الحصول عليه هما25 ) مقارنة بالمطاط الطبيعي . pphr) للمطاط الستايرين- بيوتادايين المقوى بدقائق السليكا بنسبةوكذلك عند التقوية بدقائق السليك ا يقل معدل البلى اكثر مم ا عليه عند التقوية بدقائق الالومين ا. حيثالمقوى بدقائق السليكا و الالومينا بنسبة SBR و المطاط NR بلغت قيم الصلادة و معدل البلى للمطاط25 ) موضحة بالجدول التالي: pphr)

Keywords

Elastomer --- Composites --- Hardness --- Wear Rate


Article
Effect of Microwave Disinfection on Transverse Strength and Hardness of Acrylic Resin Denture Base Materials

Authors: Ghada Y Abdul-Rahman --- Munther N Kazanji --- Alaa' N Al-Saraj
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2011 Volume: 11 Issue: 18 Pages: 284-291
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To evaluate the effect of microwave disinfection on transverse strength and hardness of acrylic resin denture base materials. Materials and methods: The samples were 112 samples (56 heat cured acrylic resin and 56 microwave cured acrylic resin) they were prepared in dimensions of 65± 0.3x10±0.03x2.5 ±0.03 mm (length, width and thickness respectively) for transverse strength test and 30x15x3±0.03 mm (length, width and thickness respectively) for indentation hardness test. The sam-ples were divided into seven disinfection groups; each one contain five samples which were (control, 900 W or 540W for 3min either inside glass flask containing 150 ml of distilled water)or along with glass flask containing 150 ml of distilled water or alone. The collected data were analyzed using analy-sis of variance (one way ANOVA) at P ≤ 0.05 and Duncan's multiple range test. Results: the transverse strength of microwave acrylic resin samples were significantly decreased except samples that disinfect-ed by 540 watt microwave energy for 3 minute with water inside microwave oven. The hardness num-ber for heat cured acrylic denture base showed no significant differences compared to control group while hardness number of microwave acrylic resin were significantly decreased in relation to control group. Conclusions: Transverse strength of microwave acrylic resin that disinfected with microwave was decreased except at 540 watt for 3 minutes with water a side in microwave oven. While heat cured acrylic resin after microwave disinfection was significantly increased compared with the control sam-ple. Rockwell hardness number for microwave acrylic resin significantly decrease in relation to control group; while for heat cured acrylic denture base showed no significancy comparing with the control group.


Article
Performance Evaluation of Electrocoagulation Technique for Removing Groundwater Hardness of Tikrit University
دراسة وتقیم كفاءة عملیة التخثیر الكھربائي في ازالة العسرة من المیاه الجوفیة الموجودة في منطقة جامعة تكریت

Author: Maha I Alali
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2012 Volume: 30 Issue: 18 Pages: 3268-3279
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The performance of Electrocoagulation (EC) process for removal of hardness ingroundwater(GW) of Tikrit University in Salahaddin province, north of Baghdad inIraq has been studied using aluminum (Al)electrodes with both bipolar andmonopolar configurations. The effect of initial pH, applied voltage(U), electrolysistime(t), and electrodes configurations on the performance of EC has beeninvestigated. It was found that the best initial pHvalue to remove hardness(HD)was9.5. The results indicated that increasing U and t had a positive effect on thehardness removal efficiency(%Ehardness ) to reach 90.4%andit was influenced by theelectrodes configuration in which %Ehardness was 83.5% in bipolar connectioncompared with 66.2%in monopolar connection.Also The electrical energyconsumption%Ehardness and the experimentally and theoreticallyelectrodesconsumption (Wexp ) and (Wtheo )were calculated.It was absorbed,as determined, thatthere is no significant difference between pseudo-first and second-order kineticmodel except at 40 volt that the pseudo second-order kinetic model fits better thanthe first-order kinetic model with the data of the electrocoagulation process. Finallythe cost at themost favorable conditions for EC process was calculatedresulting thatthe electrocoagulation process is successfully applied to remove the hardness ratefrom groundwater with high performance.

في ھذه البحث تم دراسة كفاءة علیة التخثیر الكھربائي لإزالة العسرة من المیاه الجوفیة الموجودةف ي منطق ة جامع ة تكری ت ف ي محافظ ة ص لاح ال دین باس تخدام أقط اب الألمنی وم بط رق رب ط مختلف ةوالجھد المزود ،pH أحادیةوثنائیة القطب.وقد تم دراسة تأثیر بعض المعاییر مثلا لرقم الھیدروجیني الأوليوطریق ة رب ط الأقط اب عل ى أداءعملی ة التخثی ر الكھرب ائي.وقدوج د أن درج ة ، (t) والوق ت ،(U)ك ان ل ھ أثرإیج ابي t وU ناكت 9.5 . وأشارت النتائج إل ى أنزی ادة (HD) الحموضةالأولیة المثلى لإزالةالعسرةىلع كفاءة إزالة العسرة لتصل إلى% 90.4 ، وكذلك ھي تتأثر بطرق ربط الأقطاب الكھربائیة يف الخلیةحیثناكت نسبة إزالة العسرة% 83.5 في الربط نوع ثنائي القطبین في حین وصلت في الربط أحادي القطب إل ىامك .(Wtheo ) ونظریا (Wexp ) ٪66.2 .كماتم حساب استھلاك الطاقةالكھربائیةواستھلاك الأقطاب تجریبیاتم حساب نمذجة وحركیة عملیة التخثیر الكھرب ائي، وتب ین إن درج ة حركی ة عملی ة التخثی ر الكھرب ائي م نالدرجة الثانیة كان أفضل وأدق مما في الدرجة الأولى تبعا للبیانات المستحصلة من التجارب العملیة.وأخیرا تم حساب الكلفة الاقتصادیة لھذه العملیة والتي أشارت إلى نجاح عملیة التخثیر الكھربائي في إزالة العس رةمن المیاه الجوفیة.


Article
The effect of autoclave processing on some properties of heat cured denture base material

Authors: Salwan S. Abdulwahhab سلوان عبد الوهاب --- Widad A.H. Alnakkash وداد النقاش
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 3 Pages: 13-17
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Although most of the physical and mechanical properties of denture base resin polymerized by theconventional heat polymerization have been studied, the effect of autoclave processing in these properties has notbeen fully determined. The aim of the present study is to investigate the effect of two different cycles of autoclaveprocessing on the transverse strength, impact strength, surface hardness and the porosity of acrylic denture basematerial.Materials and methods: Vertex was the heat- cured acrylic denture base material included in the study. A total of120 specimens were prepared, the specimens were grouped into: Control groups (Group A) in which acrylic resinsprocessed by conventional water- bath processing technique (74°C for 1.5 hours then boil for 30 minutes) andexperimental groups in which acrylic resins processed by autoclave at 121°C,210KPa.The experimental groups weredivided into Group B(Fast) for15min. , and Group C (Slow) for 30min... To study the effect of the autoclaveprocessing (Tuttnauer 2540EA), four tests were conducted transverse strength (Instron universal testing machine),impact strength (charpy tester), surface hardness (shore D), and porosity test. The results were analyzed to ANOVAand LSD test.Results: There were no significant differences between the results of the processing techniques regarding transverse,impact, and hardness tests. While, there were a highly significant difference in porosity test results.Conclusions: The autoclave processing technique might also be a good alternative to the conventional water bathprocessing technique. Regarding to autoclave processing technique, the slow (long) curing cycle provide betterdenture bases material including the tested physical and mechanical properties as compared with the fast (short)curing cycle.

Keywords

Autoclave --- Transverse --- Impact --- Hardness --- Porosity

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