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Article
Effect of Different Metal Bonding Agents on Shear Bond Strength of Ceramic to Direct Metal Laser Sintering

Author: Mustafa N. Abdulghani مصطفى نبيل عبد الغني
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2017 Volume: 5 Issue: 1 Pages: 109-114
Publisher: Tikrit University جامعة تكريت

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Abstract

Introduction: laser sinter Cobalt Chromium metal replacing traditional castingprocesses of dental alloys for metal ceramic restorations, appropriate bonding ofceramic to metal is an important factor for long survival time. Twenty laser sintercubic metal 10 mm for each sides was fabricated by software designing andCADCAM direct metal laser sintering technique. The twenty cubics were classifiedaccording to the type of metal to ceramic bonding agents into two groups (n=10),Ceram bond apply for group A and Crea alloy bond for group B. Samples fabricatedusing custom made silicon index was used to act as standardized mold for metalbond application and porcelain buildup. Instron with chisel indenter and specialholding device were involve to measure the strength of bond for ceramic to lasersinter metal. The mean shear bond load of group A (688.8N) was significantlyhigher than that of group B (303.2N). Application of Ceram bond to metal lasersinter produces more bond strength when compare to usage of Crea bond material.

Keywords

Ceramic laser --- Bonding


Article
Impact of Sorts Disinfection and Cleansing Material on Hardness of Different Types of Denture Base Material

Author: Reem Ahmed Shihab ريم احمد شهاب
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2017 Volume: 5 Issue: 1 Pages: 135-142
Publisher: Tikrit University جامعة تكريت

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Abstract

Dentist, dental technician and assistants are faced a several kinds of microorganisms during worklike bacteria, fungi and viruses .So, we can prevent cross contamination by using either chemicalor mechanical disinfection. The aim of the research was to measure the effect of different typesof chemical disinfection on the hardness of two types of denture base resin, heat activated acrylicand nylon (flexible). A total number of 80 denture resin specimens (40 specimens from heatactivated acrylic and 40 specimens from flexible resin) were prepared. Each type of specimenwas subdivided into 4 groups. Three groups were divided according to the type of denturedisinfectants (1%sodium hypochlorite, 1% povidine/iodine, Kin solution) and the fourth whichconsidered as control group was immersed in distilled water. All specimens were immersed intesting solution for 90 minutes at 370C. The hardness of the specimens before and afterimmersion was tested using Shore D machine. Our study showed that the mean value ofhardness test for poly methyl methacrylate higher than polyamide and there need aid nonsignificantContrast in the resistance of the surface to scratches and indentation between diversesorts of thermoplastic resin after using chemical disinfectant and denture cleansers withcomparison with control group for each type of denture base resin. The resistance to indentationof different types of denture base would not affected by short time immersion in chemical

Keywords

Ceramic laser --- Bonding.


Article
MINERALOGICAL AND INDUSTRIAL ASSESSMENT OF CLAY FROM PARTS OF THE FOLDED ZONE IN KURDISTAN REGION FOR CERAMIC PRODUCTION
التقييم المعدني والصناعي للطين من اجزاء من منطقة الطيات في إقليم كردستان لإنتاج السيراميك

Authors: Rezan Q. Faraj ريزان قادر فرج --- Tola A. Mirza توَلَة أحمد ميرزا
Journal: Iraqi Bulletin of Geology and Mining مجلة الجيولوجيا والتعدين العراقية ISSN: 18114539 Year: 2017 Volume: 13 Issue: 1 Pages: 79-97
Publisher: Ministry of Industry and Minerals وزارة الصناعة والمعادن

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Abstract

Clays are used in the ceramic industries largely because of their contribution to the molding and drying properties of the wares being produced; many clays, such as kaolinite and red clays, are used because of favorable behavior during firing or because they produce favorable properties in fired ware. To assure the most effective use of a clay, the ceramic technologist must meet the problems of purification, the improvement of the working properties of clays through additions of non-plastic materials or chemicals and their behavior during firing. Therefore this study addresses the problems of some clay deposits from parts of the folded zone in Kurdistan Region for ceramic industry. X-ray diffraction is used to establish the mineralogical composition. It is found that the main clay minerals of these samples are chlorite, smectite, mixed layer, illite, and kaolinite, in addition to the non-clay minerals such as quartz, calcite, dolomite and feldspar. The raw materials were ground and sieved; some of the raw materials were mixed in different proportions in order to prepare different mixtures. Three different mixtures were prepared using red clay sample, kaolin, granite, sandstone, and limestone. Briquettes were molded from clay alone (A) and from different mixtures (1B, 2C) using a semi-dry pressing method (10% moisture content and pressure 5.6 in/cm²) in a dimension 5 × 5 × 1 cm. The briquettes were fired at three different temperatures (1125, 1150 and 1175 °C) with at rate of heating of 30 C°/h. The evaluation tests, physical and mechanical properties as well as chemical compositions of the studied samples show that the fired briquettes made from those samples which contain considerable amount of Al2O3 and low content of CaO such as samples 1, 5 and 7 from Fatha Formation; 8 and 9 from Injana Formation give the best results for the production of floor tile, wall tile, facing tile, and clay brick industry. The results also, showed that the best mixture to adequate characteristics for ceramics industry are mixture 2C fired at 1175 °C.

يستخدم الطين في الصناعات الخزفية كثيرا وذلك بسبب قابليته في التشكيل والتجفيف والحرق حيث تتنج في النهاية الحزف: وتستخدم العديد من الأطيان في هذا المجال، مثل الكاؤلينايت والطين الأحمر، وذلك بسبب سلوك هذه الأطيان أثناء وبعد الحرق والتى تنتج خصائص ملائمة بعد الحرق. ولضمان الاستخدام الأكثر فعالية للطين، يجب على تقني السيراميك أن يعالج بالمشاكل التنقية، وتحسين خصائص الطين من خلال إضافة مواد غير بلاستيكية أو مواد كيميائية، وذلك لتحسين سلوك الطين أثناء التجفيف والحرق. لذلك فإن هذه الدراسة تتناول تقييم بعض الرواسب الطينية من اجزاء من منطقة اللطيات لصناعة السيراميك. وقد استخدمت الأشعة السينية الحائدة لمعرفة التركيب المعدني. حيث وجد أن المعادن الطينية الرئيسية لهذه النماذج هي الكلوريت, السمكتايت, الطبقة المختلطة, الإيلايت والكاولينايت، بالإضافة إلى المعادن غير الطينية مثل الكوارتز, الكالسيت, الدولوميت والفلسبار. تم طحن ونخل مواد الخام الى الأحجام المطلوبة ثم خلط المواد حسب نسب مختلفة من أجل تهيئة عدد من الخلطات.تم تحضير ثلاثة خلطات مختلفة باستخدام (ترسبات طينية ذات اللون الأحمر من منطقة اللطيات في إقليم كردستان, وتم خلطه مع الكاؤولين, كرانايت, الحجر الرملي والحجر الجيري بنسب مختلفة) وتم تشكيل قوالب بابعاد 5 × 5 × 1 سم من الطين فقط (A) وخلطات مختلفة (1B، 2C). أستخدمت طريقة الكبس شبه الجاف (بأستخدام ١٠% من الرطوبة وبتسليط ضغط قدره 5.6 كنت/سم٢) لتشكيل القوالب, ثم أحرقت تلك القوالب المكبوسة بفرن الكهربائي وبدرجات حرارة حرق ١١٢٥, ١١٥٠ و ١١٧٥ °م وفق برنامج حرق معين بحيث كان معدل الزيادة بدرجات الحرارة ٣٠ °م لكل ساعة. تم تحديد الفحوصات التقييمية التي تشمل الخواص الفيزيائية, الميكانيكية والكيميائية للعينات السيراميكية. حيث بينت نتائج هذه الفخوصات بأن القوالب التي تم إنتاجها من تلك العينات والتي تحتوي على كمية كبيرة من Al2O3 ومحتوى قليل من CaO مثل العينات 1 و 5 و 7 من تكوين الفتحة ونماذج 8 و 9 من تكوين إنجانة تعطي أفضل النتائج لإنتاج بلاط الأرضيات، بلاط الحائط، بلاط الواجهات، وصناعة الطابوق الطينى. وأظهرت النتائج أيضا أن أفضل خليط يعطى خصائص كافية لصناعة السيراميك هو خلطة 2C المحروقة في درجة الحرارة 1175 درجة مئوية.

Keywords

Briquettes --- Ceramic --- Clays --- Mineralogy --- Iraq


Article
Combined Effects of Sawdust and Building Rubbles as Aggregate on the Concrete
التأثيرات المشتركة لنشارة الخشب و أنقاض البناء كركام على الخرسانة

Author: Dalia Shakir Atwan داليا شاكر عطوان
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2017 Volume: 20 Issue: 1 Pages: 59-70
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Most of building rubbles or wastes contain some damaged materials such as cement, brick, steel, ceramic, plastic and other substances. Among these materials, ceramic and brick when using both of them as a partial replacement by the weight of conventional coarse aggregate in mixture concrete with presence of variety ratios ( 10% to 30%) for sawdust as replacement of fine aggregate, the resulting concrete properties will affected. So, this paper was based on the study some properties of concrete that produced of 50% replacement for those rubbles plus to presence 10%, 20% and 30% sawdust for both of them. The results revealed that present of sawdust with each of type of those rubbles provides database which are potential to be used in the production of lighter and economical new concrete material. Furthermore, the higher ratios of sawdust (more than 10 %) lead to obvious affected on the strength as well as other properties. While, those negative effects will perceptible improved when added 10% sawdust in ceramic aggregate concrete compared to brick aggregate concrete.

تتضمن معظم أنقاض أو مخلفات البناء على بعض المواد التالفة كالسمنت, الطابوق, حديد التسليح, السيراميك, البلاستك ومواد اخرى. ومن بين هذه المواد السيراميك والطابوق عند استخدام كلا منهم في الخرسانة كتعويض جزئي عن الركام الخشن التقليدي مع وجود نسب مختلفة من نشارة الخشب كتعويض عن الركام الناعم فأن خصائص الخرسانة الناتجة سوف تتأثر لذلك تم دراسة بعض الخصائص للخرسانة الناتجة من تعويض 50% من تلك المخلفات أضافة الى وجود 10% ,20% و 30% من نشارة الخشب لكل منهم. أظهرت النتائج بأن وجود نشارة الخشب مع كل نوع من تلك الانقاض سيوفر قاعدة بيانات بالامكان استخدامها في انتاج مادة خرسانية جديدة اقتصادية وخفيفة. بالاضافة لذلك, فأن النسب العالية من نشارة الخشب ( اكثر من 10%) ستؤثر بشكل ملحوظ على مقاومة الخرسانة فضلا عن غيرها من الخواص. بينما تتحسن تلك التأثيرات السلبية بشكل مقبول عند اضافة 10% من نشارة الخشب في خرسانة ركام السيراميك مقارنة بخرسانة ركام الطابوق.

Keywords

Building rubbles --- Ceramic --- Brick --- Sawdust --- Wastes


Article
Rotating Ceramic Water Filter Discs System for Water Filtration
منظومة اقراص مرشحات الماء الخزفية الدوارة لترشيح المياه

Authors: Riyadh Z. Al Zubaidy رياض زهير الزبيدي --- Mahmoud Al-Khafaji محمود صالح الخفاجي --- Riyadh J. M. Al-Saadi رياض جاسم محمد السعدي
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2017 Volume: 23 Issue: 4 Pages: 59-78
Publisher: Baghdad University جامعة بغداد

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Abstract

This work aimed to design, construct and operate a new laboratory scale water filtration system. This system was used to examine the efficiency of two ceramic filter discs as a medium for water filtration. These filters were made from two different ceramic mixtures of local red clay, sawdust, and water. The filtration system was designed with two rotating interfered modules of these filters. Rotating these modules generates shear force between water and the surfaces of filter discs of the filtration modules that works to reduce thickness of layer of rejected materials on the filters surfaces. Each module consists of seven filtration units and each unit consists of two ceramic filter discs. The average measured hydraulic conductivity of the first module was 13.7mm/day and that for the second module was 50mm/day. Results showed that the water filtration system can be operated continuously with a constant flow rate and the filtration process was controlled by a skin thin layer of rejected materials. The ceramic water filters of both filtration modules have high removal efficiency of total suspended solids up to 100% and of turbidity up to 99.94%.

هدف هذا العمل هو تصميم وانشاء وتشغيل منظومة جديدة بمقياس مختبري لترشيح المياه. استخدمت هذه المنظومة لفحص كفاءة اثنين من المرشحات الخزفية كوسط لترشيح المياه. تم تصنيع هذه المرشحات الخزفية من اثنين من الخلطات الخزفية من الطين الاحمر المحلي مع نشارة الخشب والماء. صممت منظومة الترشيح باثنين من وحدات ترشيح متداخلة ودوارة من هذه المرشحات. يعمل تدويرهذه الوحدات على توليد قوة قص بين الماء وسطوح اقراص الترشيح التي تعمل على تقليل سمك طبقة المواد المرفوضة على سطوح المرشحات. تتألف كل وحدة من سبعة مفردات من المرشحات، وكل مفردة تتألف من اثنين من اقراص المرشحات الخزفية.كان معدل الايصالية الهيدروليكية المقاسة للوحدة الاولى 13.7 ملم/اليوم وللوحدة الثانية 50 ملم/اليوم. بينت النتائج ان منظومة ترشيح المياه لها القابلية على العمل باستمرار بمعدل تصريف ثابت وان عملية الترشيح محكومة بطبقة رقيقة من المواد المرفوضة المتراكمة على اسطح المرشحات. تمتلك مرشحات الماء الخزفية لكل من وحدتي الترشيح كفاءة عالية في ازالة المواد العالقة الكلية تصل الى 100% وفي ازالة العكورة تصل الى 99.94%.


Article
The Effect of Artificial Accelerated Aging on The Color of Ceramic Veneers Cemented With Different Resin Cements (A Comparative In Vitro Study)

Authors: Shatha Kh. Hussain --- Inas I. Al-Rawi
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 1 Pages: 39-46
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Color changes that are detectable to human eye can affect the esthetic appearance of ceramic veneers. The purpose of this study was to evaluate and compare the effect of artificial accelerated aging on the color of ceramic veneers cemented with different resin cements.Materials and Methods: Sixty discs were prepared with 0.5 mm thickness, 30 discs made from IPS e.max press (Ivoclar Vivadent) and 30 discs were made from VITA Enamic (VITA Zahnfabrik). The discs were cemented with three resin cements: Variolink Veneer MV 0 shade (Ivoclar Vivadent), Rely X veneer Translucent shade (3M ESPE) and NX3 Nexus Clear shade (Kerr Corporation) with 0.1 mm thickness. The spectrophotometer Easyshade Advance was used to measure the color parameters (Lightness, axis a* of chroma and axis b*of chroma) immediately after cementation, after 150 and 300 hours of aging. The specimens were subjected to artificial accelerated aging in Accelerated Weathering Tester. Color change greater than 3.3 was considered unacceptable. One-way ANOVA, paired t-tests and Bonferroni adjusted t-test were used for statistical analysis (p <0.05).Results: Artificial aging caused high significant color change in both ceramic types, but there were non-significant difference in color change among the three resin cements used. The color change was between1.997-14.8 after 150 hours and it was between 2.179-15.68 after 300 hours. The color change of e.max discs after aging were within acceptable limit<3.3 whereas Vita Enamic specimens had shown unacceptable color change >3.3 after aging.Conclusions: The majority of color change after aging related to veneering materials while resin cement have only slight effect on color change after aging. IPS e.max had shown an acceptable color change after aging, so it is suitable for fabrication of restorations in esthetic zone while Vita Enamic should not be used in esthetic zone since it has poor color stability according to the results of this study


Article
Marginal Discrepancy and Fracture Resistance of CAD/CAM Ceramill Sintron Metal Copings with Different Porcelain Materials

Authors: Ammar A. Al-Sa'ady --- Mustafa N. Abdulghani --- Eanas I. Jellil
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 2 Pages: 7-12
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This study was performed to compare the marginal fit changes and facture resistance of metal ceramiccrowns constructed from Ceramill Sintron metal coping veneered with three different porcelain veneering materials(Vita Master Koromikos VMK, Willi Geller Creation CC and GC initial MC), also to evaluate the influence ofthermocycling on load at fracture.Materials and Methods: Master brass die was scanned ,then metal coping was designed and milled from CeramillSintron blank to get 60 metal copings, then divided randomly into three groups(20 sample), then veneered withporcelain: VITA, Creation or GC. The marginal gaps were measured before and after porcelain veneering thenmarginal fit changes was calculated. Fracture resistance test was done by Instron®, the master die was duplicatedto sixty analogs then each analog was fixed into acrylic base. After that each crown was cemented onto thecorresponding die analog. Ten samples of each group were subjected to compressive loading to fracture and otherten subjected to thermocycling followed by compressive loading to fracture.Result and Conclusion: The result of marginal fit changes showed that GC group had the lowest marginal gap followby VITA and Creation. While VITA group showed the highest fracture resistance follows by GC then Creation.Thermocycling process did not significantly reduce the load at fracture for all groups


Article
Evaluation of the effect of surface treatments on shear bond strength between lithium disilicate ceramic and dentin

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Abstract

Purpose: To evaluate the effect of different surface treatments on shear bond strength between dentin and IPS e.max lithium disilicate glass-ceramic.Materials and Methods: Eighteen extracted third molars were embeded in epoxy resin. The tooth was sectioned vertically in mesiodistal direction using a low speed hard tissue microtome. The buccal and lingual surfaces of each section were ground flat using 600 grit Silicone carbide paper. Eighteen ceramic discs consisted of lithium disilicate glass-ceramic were prepared with a diameter of 4.7mm and height of 2.2mm. The discs were divided in two groups (n=10): (1) IPS e.max treated with hydrofluoric acid and Monobond Plus (MBP) and (2) IPS e.max treated with Monobond Etch &Prime (MBEP). The tooth was cemented with Multilink Automix and stored for 24hours at room temperature before thermocycling and subsequently loaded to failure in Universal Testing Machine. Failure mode were recorded for each specimen.Result: Bond strength analysis and t-test analysis MBEP demonstrated the higher shear bond strength (SBS). MBP and MBEP showed no statistically significant difference were found between them. One-way ANOVA and t-test was used to determine differences in bond strength within and between the groups. Cohesive failure in resin cement was predominant with higher results while adhesive and mixed with lower and equal.Conclusion: Surface treatment with Monobond Etch and Prime has a favorable effect on SBS between dentin and lithium disilicate glass-ceramic with resin cement compared with Monobond Plus.


Article
Effect Nano-SiC Additives on Physical and Mechanical Properties of Bauxite Refractories Used in Oil Treatment Units

Authors: S.A. Zaidan --- H. H. Jasim
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 10 Part (A) Engineering Pages: 992-998
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Refractory mixtures were prepared from: bauxite raw materials, grog and Kaolin. Different weight percentage of micro-SiC (5, 10, 15 and 20 wt%) and nano-SiC (2.5,5,7.5 and 10 wt%) was added to bauxite mixture to improve the refractories characteristics to suit the lining of oil treatment units. Semi-dry pressing used to forming cylindrical specimens with load (7 ton) and 25 mm in diameter after mixing the powder with 10 wt% Sodium Silicate as a binder. The specimens dried at (110 oC) for (2 h) and fired at (1400 oC) with soaking time (2 h). During firing process, some of nano-SiC powder oxidants and transformed to SiO2 glass phase with increasing mullite phase. Therefore; the bonds with bauxite increases as a result glass phase generated and lead to decreasing the porosity and increasing the shrinkage, density and mechanical properties compared with micro-SiC additives.


Article
Improvement the Chemical Resistance of Furnaces Bricks for Petroleum Refineries by ZrO2-Nano- Glass-Ceramic Coated

Authors: S.A. Zaidan --- H. Y. Abed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 10 Part (A) Engineering Pages: 999-1002
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Partial Stabilized Zirconia (PSZ) was prepared from adding 3 wt % of MgO or adding 8 wt% of Y2O3 to 90 wt % ZrO2 Powder and mixed by wet method, then dried and firing mixture to 1500C to obtain PSZ ceramic powder. Glass-Ceramic (Li2SiO3) and (LiAlO2) prepared by dissolve lithium carbonate and lithium hydroxide with Nano-Silica (SiO2) and Nano-Alumina (Al2O3) respectively. Those glass-ceramic mixed with PSZ in different percentage (2.5,5,7.5,10) and sprayed on furnaces bricks for petroleum refineries. An increase in the chemical resistance of the acid on the surface of the Refractory bricks was observed when coating with the glass-ceramic mixture, as well as increasing the hardness and thermal shock resistance. Lithium silicate coated specimens are more spared and homogeneous on the surface compared to lithium laminate coated.

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