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Article
Evaluation of transverse and tensile bond strength of repaired nylon denture base material by heat, cold and visible light cure acrylic resin

Authors: Firas A.F. --- Ghazwan A.A. --- Ali A.M.
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: special issue 1 Pages: 1-5
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Denture fracture is one of the most common problems encountered by the patients andprosthodontists. The objective of present study was to evaluate the transverse strength of nylon denture base resinrepaired by using conventional heat polymerized, autopolymerized and visible light cure {VLC} resins, surfacetreatment that used for repair and adjustment of insufficient nylon denture bases and in case of addition of artificialteeth. As these corrective procedures are common chair side procedures in dental clinic.Materials and methods: One hundred twenty nylon specimens were prepared by using metal patterns withdimension of (65x10x2.5 mm) length, width, and thickness respectively for transverse strength test while for tensilebond strength a dumbbell-shaped with measurement (65x12.5x25mm) length, width, and thickness respectively wereflasked with stone. The nylon specimens were molded by reflasked with dental stone that used as an index for thesespecimens in the repair procedure and repaired with 45 degree bevel joint by using metal holding device. The twoparts of nylon specimen to be repaired were realigned in its repair index and adhere with special adhesive materialto stabilize the combination during repair procedure. The dough of heat and cold cure resin was packed into thejoint and then cured. The specimen repaired with cold cure resin was placed in the Ivomat containing water at(40°C) and pressure (30IB/inch²) for 15 minutes. The specimen repaired with {VLC} was placed in the light cure unit for4 minutes following manufacturer’s instruction. The fractured nylon specimens were divided according to the type ofrepaired materials into (40) specimens received heat cure acrylic and the (40) specimens received cold cure acrylicand the other 40 specimens received {VLCR}. Each 40 specimens were subdivided according to the type of surfacetreatment received into 20 specimens were treated with coarse stone bur (control), 20 specimens were treated withcombination of coarse stone bur and monomer of the heat cure acrylic. After that the specimens were subjected totransverse {Tr} and tensile bond {TB} strength tests. For each test 10 specimens.Results and conclusions: This study showed that specimens treated with combination of coarse stone bur andmonomer of the acrylic (heat, cold or VL cure) had the highest transverse and tensile strength values, followed bythe specimens treated with coarse stone bur. The results showed that the specimens repaired with heat cure acrylichad transverse and tensile strength values higher than the specimens repaired with cold and VL cure acrylic whencompared between subgroups of heat, cold and VL cure acrylic that received the same treatments


Article
Effect of Filler Type on some Physical and Mechanical Proparties of Carbon Fibers / Polyester Composites
تأثیر نوع الاضافه على بعض الخواص الفیزیائیه والمیكانیكیه من الیاف كاربون ومتراكبات البولي استر

Authors: Osama Sultan Muhammed --- Abbas Khammas Hussein --- Ruaa Haitham Abdel-Rahim
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2013 Volume: 31 Issue: 15 Part (A) Engineering Pages: 2905-2924
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In the present study, traditional and hybrid composites were prepared by Hand lay-upmolding and investigated. The composites constituents were unsaturated polyester resinas the matrix, 3% and 6% volume fractions of carbon fibers as reinforcement and 3% ofAl2O3, Al, Cement and local Gypsum (calcium sulfate anhydrate CaSO4) as fillerparticles. The investigated physical properties were density, porosity while themechanical properties were tensile properties, bending modulus of elasticity. Theexperimental results showed that increased volume fraction of carbon fibers to (6%) ledto increase in physical properties (density, porosity. As for the mechanical properties,carbon fiber composites and (3% carbon fibers/Al2O3)-contained hybrid composites gavethe higher tensile and fracture strength, carbon fiber then gypsum composites gave thehigher bending modulus.


Article
Evaluation the Effect of Different Methods of Disinfection on Tensile Strength and Bond Strength of Soft Denture Lining Ma-terials

Author: Lamia T Rejab
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 1 Pages: 58-65
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: Aim of the study to evaluate the effect of two different disinfection methods for two periods of time on tensile strength and bond strength of soft denture lining materials (Vertex and Molloplast-B). Materials and methods : The effect of two disinfection methods ,first chemical disinfection method (which include artificial saliva , saturated salt and vinegar solution), and second microwave method on two physical properties the tensile and bond strength of soft denture lining materials for two periods of times (14 and 30 days) was evaluated, two hundred samples were prepared, one hundred samples to each property test . ANOVA and Duncan's multiple range test were performed to determine the signifi-cant difference among the tested groups at p ≤ 0.05% . Results: The result showed that the highest val-ue of tensile and bond strength of Vertex after 14 and 30 days were achieved with the microwave group, while for Molloplast -B highest value achieved with the control distilled water group. The low-est value was achieved after immersion in vinegar group for both soft lining material. A significant difference between the two soft lining materials among all disinfection methods at p≤ 0.05.Conclusions : The results appeared that the chemical disinfection and microwave disinfection methods have a significant effect on the tensile strength and bond strength of both vertex and Mol-loplast –B soft ling materials for two periods of time. Microwave disinfection has less effect than the chemical disinfection on the properties. The effect of disinfection increase significantly with increas-ing period of time .


Article
Study of Fracture Energy for Plain Concrete by the Use of the Finite Element Method
دراسة طاقة الكسر في الخرسانة الاعتيادية باستخدام طريقة العناصر المحددة

Author: Abdulameer Q. H.
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2013 Volume: 31 Issue: 8 Part (A) Engineering Pages: 1534-1542
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Failure of plain concrete in tension is characterized by softening, which is accompanied by the development of regions of highly localized strains. The main objective of this research is to study the fracture energy (the value of tensile strain) 〖ε_tu〗^ in the concrete and its effects on the load for plain concrete beams. Beams were tested by Bosco and analysis by the use of computer program ANSYS. The three dimensional brick element was used to represent the concrete element. The results confirmed that the plain concrete beams do not fail when the first crack is obtain, but depends on the value of the tensile strain 〖〖 ε〗_tu〗^ (fracture energy), where the increase in the value of the tensile strain due to increases in the load applied on the beam.

الخلاصة الفشل في الخرسانة العادية عند منطقة الشد عبارة عن ليونة في خصائص الخرسانة ويكون عادة مصحوب بتوسيع المنطقة التي فيها انفعال عالي جدا لذلك فان الهدف الأساس من هذا البحث هو دراسة طاقة الكسر(قيمة انفعال الشد) 〖〖 ε〗_tu〗^ في الخرسانة وتأثيراتها على تحمل العتبات الغير مسلحة حيث تم أخذ عتبات فحصت من قبل Bosco وتم تحليلها باستخدام برنامج ANSYS واستخدام العنصر الطابوقي المتكون من ثمان عقد لتمثيل العناصـر الخرسانية. الدراسة أكدت أن العتبات الخرسانية لا تفشل عند حصول أول تشقق بل تعتمد على قيمة انفعال الشد ( طاقة الكسر) 〖〖 ε〗_tu〗^ حيث عند زيادة قيمة انفعال الشد يزداد تحمل الأعتاب الخرسانية.


Article
Efficiency of Dissimilar Friction Welded (Super Duplex Stainless Steel SAF 2507- Mild Steel) Joints (English)
"كفاءة وصلاة اللحام الاحتكاكى غير المتشابه بين الصلب المقاوم للصدأ المزدوج المتناهىSAF 2507 والصلب الطري"(English)

Authors: Ramadhan H Gardi رمضان حسين الجردي --- Salm Aziz Kako سالم عزيز كاكو
Journal: AL-Rafdain Engineering Journal (AREJ) مجلة هندسة الرافدين ISSN: 18130526 Year: 2013 Volume: 21 Issue: 1 Pages: 56-65
Publisher: Mosul University جامعة الموصل

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Abstract

Abstract The aim of this research paper is to investigate the efficiency of dissimilar friction welded super duplex stainless steel SAF 2507 and mild steel joints. The joints were obtained using rotary friction welding process. Friction pressure and forging pressure are varied in three different cases but rotational speed and friction time are kept constant .The joints were subjected to tensile strength and metallographic study. The tensile strength of welded joints compared to that of SDSS SAF 2507 and mild steel in as received condition. The joint efficiency were calculated .The tensile strength and joints efficiency decreased with increasing friction pressure and forging pressure .The results attributed to change in mechanical, physical properties ,and micro structural changes of welded joints like change in ferrite to austenite percent, precipitation of carbides and nitrides ,sigma phase,….etc. Key words: Friction welding, super duplex stainless steel, tensile strength

الخلاصة الغرض فى هذا البحث هو دراسة كفاءة وصلات اللحام الاحتكاكى غير المتشابه بين الصلب المقاوم للصدآ المزدوج المتناهى SAF2507 والصلب الطرى . تم الحصول على الوصلات وذلك باستخدام اللحام الاحتكاكى وبتغير كل من الضغط الاحتكاكى وضغط التشكيل فى ثلاث حالات مختلفة ،ولكن زمن الاحتكاك والسرعة الدورانية كانا ثابتين فى جميع الحالات. تم دراسة مقاومة الشد والبنية المجهرية لوصلات اللحام . وتم مقارنة مقاومة الشد لوصلات اللحام بمقاومة الشد لكل من الصلب المقاوم للصدآ المزدوج المتناهى SAF2507 والصلب الطرى كما فى الحالة المستلمة وتم حساب كفاءة الوصلاة.مقاومة الشدوكفاءة الوصلات تقل بازدياد كل من الضغط الاحتكاكى وضغط التشكيل .النتائج تعود الى تغير الخصائص الميكانيكية والفيزياوية والبنية المجهرية لوصلات اللحام خلال عملية اللحام مثل تغير نسبة الفيرايت والاوستنايت وترسيب الكاربيدات والنيتريدات وطور السيكما ....الخ. الكلمات الدالة:اللحام الاحتكاكى، الصلب المقاوم للصدا المزدوج،مقاومة الشد


Article
دراسة اختباري الشد والكلال لمادة الايبوكسي ومتراكباتها الهجينية

Author: رغد حامد هلال / مدرس
Journal: Iraqi journal of mechanical and material engineering المجلة العراقية للهندسة الميكانيكية وهندسة المواد ISSN: 20761819 Year: 2013 Volume: 13 Issue: 1 Pages: 144-152
Publisher: Babylon University جامعة بابل

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Abstract

This research is concerned the use of Epoxy resin( Cy223 ,Hy956 )which supplied from (Giba –Giegy) German company .It is a viscause liquid have a certain properties like high adhesives and low shrinkage at dry condition with addition of the hardener at ratio (1:3 ) of the resin with density about (1150 kg/m3 ) , the matrix resin forced with two type of fibers : glass fiber( E-glass) and carbon fiber (HS )(High Strength) ,the ratio of carbon fiber layers to glass fiber layers is (1:5) with volume fraction (30%) at room temperature to study tensile and fatigue tests. It is noted that the composite materials appears better resistance to the tensile test than the resin due to the resistance of fiber(especially carbon fiber which have a good mechanical properties ) .In the fatigue test , the composite material show good strength to break because of the resistance of carbon fiber at low cycle . The resistance to break remains constant or changed slowly with increasing cycle of fatigue strength depending on supporting ratio.

تم في هذا البحث استخدام راتنج الايبوكسي (HY956 , CY223 ) [Digly Cidyle ether of Bipherio ADGEBA CY 223 ] المجهز من شركة (Giba –Giegy ) الالمانية وهو سائل لزج ذو مواصفات معينة ومنها قابلية التصاق عالية ،أضافة الى قلة الانكماش عند الجفاف ،أما المصلد المستخدم فهو HY956 ، يضاف المصلد الى الراتنج بنسبة ( 1 : 3 )، أما الراتنج فهو ذو كثافة مقدارها (1150 kg/m3 ) كمادة أساس مدعمة بنوعين من الالياف هما ألياف الزجاج نوع (E-glass ) والياف الكاربون (HS ) (High Strength ) وبنسبة عدد طبقات الياف الكاربون الى الزجاج (5 : 1 ) وبكسر حجمي (%30) في درجة حرارة الغرفة لدراسة أختباري الشد والكلال . وقد لوحظ ان مقاومة الشد للمادة المدعمة او المتراكبة اعلى منها في حالة المادة البوليمرية لوحدها بسبب مقاومة الالياف ( خصوصاً الياف الكاربون لامتلاكها خواص جيدة ) .أما بالنسبة لاختبار الكلال تبدي المادة المتراكبة مقاومة جيدة للكلال مقارنة بالمادة البوليمرية لوحدها حيث ان قوة او مقاومة الياف الكاربون للكسر عند الدورات القليلة يؤدي الى عدم تعرض المادة المتراكبة للكسر . اما في الدورات العالية فأن مقاومة الكلال للمادة المتراكبة تبقى على الاغلب ثابتة او تتغير ببطىء مع زيادة عدد دورات الكسر وبالاعتماد على نسبة التدعيم .


Article
Effect of Curing Condition on the Engineering Properties of Fiber Reinforced Concrete

Author: Ilham Hatim Khuthair Alubaidi
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2013 Volume: 21 Issue: 2 Pages: 646-654
Publisher: Babylon University جامعة بابل

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Abstract

The paper reports an experimental study investigating the influence of curing conditions on the engineering properties of fiber reinforced concrete (FRC) . Portland cement (PC) concrete and two types of FRC , i.e. SFRC with 1% by volume steel fiber reinforcement and PFRC with 1% by volume poly propolylene reinforcement specimens are prepared and cured in two different curing conditions , namely water and air conditions for the periods of 3,7,14 and 28 days . At the end of each curing periods , compressive and tensile strength and ultrasonic velocity (UPV) values are determined . The results showed that water curd specimens always give the highest values then air condition irrespective of type and age of concrete and test method for both compressive and tensile strength tests , the PFRC gives the highest values followed SFRC and then PC concrete for all curing periods and conditions , also , the UPV results showed that the highest values are obtained from the PFRC and then from the SFRC and PC concrete for all curing conditions

يبين البحث دراسة عملية لتأثير طرق المعالجة على الخصائص الهندسية للخرسانة المسلحة بالألياف وكونكريت الأسمنت البورتلاندي ، لقد استخدم الأسمنت البورتلاندي مع نوعين من الألياف المسلحة وبنسبة حجميه 1% من ألياف الحديد و1% من ألياف البولي بروبلين تم تحضيرها معالجتها تحت ظروف مختلفة متمثلة بالماء أولا وبالهواء ثانيا وبفترات 3، 7،14 و28 يوم . وفي نهاية كل فترة معالجة تم تعيين مقاومة الشد والانضغاط وسرعة الأمواج فوق الصوتية . لقد بينت النتائج أن النماذج المعالجة بالماء أعطت قيم أعلى من النماذج المعالجة بالهواء بغض النظر عن نوع وعمر الكونكريت وطريقة الفحص لكلتا الخاصيتين الانضغاط والشد . أن الخرسانة المسلحة بألياف البولي بروبلين أعطت قيم عالية مقارنة بالخرسانة المسلحة بألياف الحديد وخرسانة الأسمنت البورتلاندي لكل فترات المعالجة . وهدا ما أظهرته نتائج فحص الأمواج فوق الصوتية ولكل ظروف المعالجة.


Article
Static tensile strength and fatigue behavior of polyester reinforced with the chopped strand mat (CSM) offiber glassat elevated temperature
مقاومة الشد وسلوك الكلال لمادة البولسنر المدعم بطبقات اللالياف الزجاجية نوع(حصيرة الخيوط القصيرة )عند درجات حرارة مختلف

Authors: Abdul-jabar H. Ali عبد الجبارحسين علي --- Dhafir S. Al-Fattal --- Hussain J. Al-alkaw حسين جاسم العلكاوي
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2013 Volume: 17 Issue: 3 Pages: 37-53
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

In the work present, describes an attempt has been made to study the effect of temperature on fatigue behavior of polyester reinforced with woven of fiber glass manufactured as a laminate [CSM]3.Fatigue tests were carried out at constant stress amplitude at different temperature environment. All fatigue tests were employed at stress ratio R=-1 and under constant fiber volume fraction (VF) of 33%. The results indicated that the tensile and the fatigue strength decreased with increasing temperature up to at 60 0C.The fatigue life reduction factor (FLRF) at 60 oC was in range (41%-61%) in range of applied stresses amplitude between (80-100MPa) compared at (RT).

الهدف من هذا العمل هو دراسة تأثير درجة الحرارة على مقاومة الشد وسلوك الكلال لمادة البولستر المدعم بطبقات الالياف الزجاجية نوع (حصيرة الخيوط القصيرة) وبنسبة حجمية قدرها 33%. اظهرت النتائج ان مقاومة الشد ومقاومة الكلال تقل مع زيادة درجةالحرارة الى 60 درجة مئوية . وان معامل تخفيض عمر الكلال عند 60 درجة مئوية كان بحدود (41%-61%) ضمن تأثير سعة اجهادات مسلطة ما بين (80 -100 ميكا باسكال) مقارنة عند درجة حرارة المختبر


Article
Effect of Siwak on Certain Mechanical Properties of Acrylic Resin

Author: Hanan Abdul- Rahman Khalaf
Journal: Journal of Oral and Dental Research مجلة طب الفم والاسنان ISSN: 23106417 Year: 2013 Volume: 1 Issue: 1 Pages: 39-49
Publisher: Iraqi Association for Oral Research الجمعية العراقية لبحوث طب الفم

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Abstract

Background: (PMMA) has been used in dental prosthetic devices for almost 70 years;three features have contributed for its success: excellent appearance, simple processingtechnique and easy repair. However, the resistance to impact and fracture of PMMA duringfunction is low. Various methods for enhancing strength of the acrylic resin denture baseshave been reported. This study was designed to evaluate the effect of adding Siwak powderwith average particle size of (75 µm) in three different concentrations by weight to PMMAon certain mechanical properties. Material and Methods: Tensile strength, elongation,transverse strength, impact strength, compressive strength and the surface roughness ofheat- polymerized acrylic resin specimens were evaluated for both the control group A(0%) and the experimental groups. These groups consisted of acrylic resin mixed withdifferent proportions of Siwak powder B (3%), C (5%) and D (7%) by weight. Stainlesssteel samples with dimensions of (65 mm, 12.5 mm, 2.5 ± 0.03 mm) length, width, andthickness were constructed for testing tensile strength and elongation of acrylic resin. Otheruniform molds were made by investing machined stainless steel standards (65 mm 10 mm,2.5 mm) for testing denture base materials in surface roughness and these specimens werereused for transverse deflection test. For testing the impact strength and compressivestrength of acrylic resin, wax patterns (60 mm,10 mm, 10 mm) and (20 mm,10 mm, 10mm) length, width, thickness were prepared. Results: Siwak powder (5%) did not greatlyaffect the tensile strength and compressive strength (P = 0.05). The addition of Siwakpowder at ratio of (3%) did not greatly affect impact strength of the experimental group incomparison to the control group, while the addition of (7 %) Siwak powder revealed asignificant decrease in tensile strength, impact strength and compressive strength incomparison to the control group. Conclusion: Addition of low concentrations (3%, 5%)Siwak to the heat polymerizing acrylic resin did not affect significantly the testedmechanical properties.


Article
Creep Behavior in Fiber-Reinforced Epoxy (DGEBA) Composites
خاصیة الزحف في الألیاف المدعم بمتركبات الایبوكسي

Author: Lubna Ghalib
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2013 Volume: 31 Issue: 1 Part (A) Engineering Pages: 12-25
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The composite material was prepared by reinforcing the epoxy with E-glass fiber. The creep and flextural test were measured in this work for one and two layer of E-glass fiber with volume fraction rate of (10%, 20%, 30%, and 40%) in orientation of (0-90o) immersed in epoxy (DGEBA) resin with total thickness of 4mm. The tests were done at different temperature levels from (25 to 55)Co for creep test. The results had revaluated showing that the creeping properties of this composite materials will be improved with increasing the volume fraction layer of fiber at different temperature levels with constant stress. Creeping increases when the temperature increases and decreases with increasing of the number of layers and volume fraction of fiber. The creep constant increases with increasing the temperature up to 45Co then the creep constant down. The creeping energy of epoxy E-glass (epoxy composite) increases with increasing the volume fraction rate of E-glass fiber.

إن المواد المتراكبة تحضر بتقوية مادة الايبوكسي بالألياف الزجاجية نوع E)) . تجربة الزحف و الانحناء تم قياسها في هذا البحث لطبقة وطبقتين من الألياف الزجاجية نوع (E) وبنسبة حجميه (10%, 20%, 30%, 40%) وباتجاه (0°-90°)مغمورة في الايبوكسي DGEBA) ) وبسمك إجمالي قدره (4 ملم).تم أجراء اختبارات الزحف في درجات حرارة مختلفة تراوحت مابين (25-55) م° . أظهرت النتائج بعد إن تم تقييمها من إن خواص الزحف لمثل هذه المواد المتراكبة قد تحسنت بزيادة النسبة الحجمية لطبقة الألياف الزجاجية عند مختلف درجات الحرارة وتحت إجهاد ثابت.أظهرت النتائج إن الزحف يزداد عندما تزداد درجة الحرارة ،وكذلك فان الزحف يقل بزيادة عدد طبقات الألياف وكمياتها . إن ثابت الزحف يزداد بزيادة درجة الحرارة ولحد (45 م° ) وبعدها يقل ثابت الزحف ،حيث إن طاقة الزحف للايبوكسي المقوى بالألياف الزجاجية عندها يزداد بزيادة النسبة الحجمية للألياف الزجاجية.

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