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Article
The effect of different types of mouth washes on the modulus elasticity of elastic ligature

Author: Wael Abdul Razzak Al waelly
Journal: Muthanna Medical Journal مجلة المثنى الطبية ISSN: 2226146x Year: 2017 Volume: 4 Issue: 1 Pages: 1-7
Publisher: Al-Muthanna University جامعة المثنى

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Abstract

The mouth washes are widely used for maintain oral hygiene for patient wearing fixed orthodontic appliances but had effect on the elastic ligature so it’s important to measure the modulus elasticity of elastic ligature. This study was carried out to evaluate the effect of different type of mouthwashes on modulus elasticity of the elastic ligature. A 40 elastic ligatures were selected from commercially available clear elastic ligature, the elastics were adjusted on S.S brackets which were bonded to maxillary right first premolar by chemical composite, the elastic ligatures were divided into four main groups and each group had 10 elastics as follows: group A. 10 elastic ligatures were immersed in a pool distilled water at 37c instead of saliva. Group B. 10 elastic ligatures were immersed in bio fresh. Group C. 10 elastic ligatures were immersed in corsodyl. Group D, 10 elastic ligatures were immersed in parodontax. All samples were then tested to determine the modulus elasticity by instron machine. The Paradontax mouthwash group provided a higher value of mean of the modulus elasticity of the elastic ligature followed by distilled water and Corosydel groups. The biofresh had the least value of mean of the modulus elasticity. There were highly significant differences between control and Corosydel; and control and biofresh groups (P≤0.01). No significant differences, however, between control and paradontax groups (P≥0.05). In conclusion, the Paradontax mouthwash group had a great effect on the modulus elasticity of the elastic ligature. The biofresh had the least effect on the modulus elasticity.


Article
Nonlinear Analysis of Thermoviscoelasticity of Laminated Composites
التحليل اللاخطي للمواد المركبة اللزجة المرنة تحت تأثير الحرارة

Authors: Muhsin J.Jweeg --- Adnan M. Al-Sultany --- Raed Naeem Hwyyin
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2010 Volume: 28 Issue: 14 Pages: 4703-4721
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The nonlinear thermoviscoelastic behavior of composite thin plates isinvestigated. An experimental program covers an achievement of creep tests under different temperatures, dimensions of specimens and distribution loads to describe the equation of creep compliance. The stress relaxation is also determined from the experimental creep compliance. A new equation of creep compliance function D(ts, ,T) and relaxation modulus E(t,e,T) were predicted from the experimental results to describe the nonlinear thermoviscoelastic behavior of composite thin plates. A good agreement has been observed between the proposed models of nonlinear behavior at different temperatures and experimental results and between both theoretical and FEM results.It was found that thus the deflection is increasing at the beginning and the rate of increase is nearly constant and increase with increasing temperature from 30 Co to 60 Co with approximate rate (34.6%) for simply support plate at distributed load (q=1.934E-3 N/mm2), relative dimensions (a/b)=1.0 and time=15 min.The results indicate that the shear stress increases with rate (50.7%), so that strain in y-axis increases with rate (19%) as a result of increase the temperature from (30 Co to 60 Co).

تم بحث السلوك اللاخطي الحراري للمواد اللزجة المرنة لمادة مركبة لصفيحةنحيفة.يتضمن الجانب العملي إنجاز اختبار الزحف عند درجات مختلفة، أبعاد مختلفة للعينة وحمل موزع لوصف السلوك اللاخطي الحراري من خلال معادلة مطاوعة الزحف . إجهاد الاسترخاء يحدد من النتائج العملية لمطاوعة الزحف.تم اشتقاق معادلة جديدة لوصف خضوع التزحييف ومعامل الاسترخاء من النتائج العملية لوصف السلك اللاخطي الحراري اللزج – المرن لصفيحة نحيفة مركبة.وجدت الدراسة إن معدل الزيادة الحاصلة في الانحراف عالية في البداية ثم يقل معدل الزيادة 30 ) مما Co-60 Co) ليقترب من الثبات كما إن الانحراف يزداد مع ازدياد درجة الحرارة من يزيد معدل الانحراف بمقدار (% 34.6 ) ومعدل الزيادة الحاصلة في إجهاد لقص بمقدار وأبعاد نسبية (q=1.9634E-3N/mm 50.7% ). لصفيحة العتبة البسيطة وعند حمل منتشر( 2 ) .(time=15 min) وعند زمن (a/b=1.0) وجد تطابق جيد بين النتائج السلوك اللاخطي الحراري والنتائج العملية وكلا من النتائج النظرية ونتائج طريقة العناصر المحددة.الكلمات المرشدة:اللزوجة- المرنة الحرارية، إجهاد الاسترخاء، معامل الاسترخاء، خضوع التزحييف.


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
Effect of Polymers on Permanent Deformation of Flexible Pavement
تأثير البوليمرات على التشوه الدائمي للتبليط المرن

Authors: Mohammed Qadir Ismael محمد قادر اسماعيل --- Hamid Mahmoud Hamdou حامد محمود حمدو --- Mohammed Assi Abed محمد عاصي عبد
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2014 Volume: 20 Issue: 12 Pages: 150-166
Publisher: Baghdad University جامعة بغداد

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Abstract

The permanent deformation of flexible pavement represent serious problem in hot climate region. Numerous efforts are devoted to mitigate this distress such as modifying asphalt binder by polymers. The present study demonstrate the effect of utilizing four types of polymers to reduce the permanent deformation, these polymers are Polyethylene Wax (PEW), Styrene Butadiene Rubber (SBR), Ethylene Propylene Dien Monomer (EPDM) and Ethylene Vinyl Acetate (EVA). The prepared mixtures composed of 4.9 % of 40/50 asphalt binder, 12.5 mm nominal aggregate maximum size and limestone dust as filler. The permanent and resilient strains have been recorded when the cylindrical specimens, 101.6 mm in diameter and 203.2 mm in height, tested by repeated loading system. The main conclusions exhibit that SBR and EPDM with the same concentration (15 % by weight of asphalt binder) reduced the permanent deformation by 30.20 % and 30.46 % respectively. Although, the PEW and EVA reduced permanent deformation by lower values, 13.24 % and 17.35 % respectively, but the incremental percentage of their action are higher. The influences of testing temperature and stress level on permanent deformation were investigated. Linear regression model was established to correlate the values of permanent deformation and the resilient modulus of asphalt mixtures.

يمثل التشوه الدائمي للتبليط المرن مشكلة جدية في مناطق المناخ الحار، جهود عديدة وجهت لتقليل هذا الضرر مثل تعديل الرابط الاسفلتي بالبوليمرات. تعرض الدراسة الحالية تاثيراستخدام اربع انواع من البوليمرات لتقليل التشوه الدائمي، هذه البوليمرات هي شمع البولي اثيلين (PEW)، مطاط الستايرين بوتادين (SBR)، إيثيلين بروبيلين ديين مونومر(EPDM) و خلات فينيل الاثيلين(EVA) .الخلطات المعدة تتكون من 4.9% رابط اسفلتي 40/50، 12.5 مم مقاس اقصى اسمي للركام وغبار حجر الكلس كمادة مالئة. الانفعالات الدائمية والمرنة تم تسجيلها عندما فحصت النماذج الاسطوانية بقطر 101.6مم وارتفاع 203.2مم بنظام الاحمال المتكررة.اظهرت النتائج الرئيسة بان SBR و EPDM ولنفس نسبة التركيز (15% من وزن الرابط الاسفلتي) قللتا التشوه بمقدار 30.20% و 30.46% بالتعاقب. رغم ان PEW و EVA قللتا التشوه بقيم اقل، 13.24% و 17.35% بالتعاقب ، لكن النسبة التزايدية لفعلهما كان اكبر. تم بحث تاثير حرارة الفحص ومستوى الاجهاد. تم تكوين انموذج انحدار خطي لربط قيم التشوه الدائمي ومعامل المرونة للخلطات الاسفلتية.


Article
Intertwining approximation in space ,
التقريب المتشابك في الفضاء

Author: Nada Zuhair Abd AL-Sada ندى زهير عبدالسادة
Journal: Journal of Al-Qadisiyah for Computer Science and Mathematics مجلة القادسية لعلوم الحاسوب والرياضيات ISSN: 20740204 / 25213504 Year: 2018 Volume: 10 Issue: 2 Pages: 64-69 Math
Publisher: Al-Qadisiyah University جامعة القادسية

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Abstract

In this paper, we find the degree of best approximation between a pair of a nearly intertwining polynomials, and a pair of a nearly intertwining splines to a non-negative function f∈L_(ψ,p) (I)∩∆^0 (j_s ) , in , , we find the order of best a nearly intertwining approximation in the above terms.

في هذا البحث تم ايجاد درجة افضل تقريب لزوج من متعددات الحدود المتشابكة بين زوج من شرائح متعددات الحدود المتشابكة تقريبا للدالة المقيدة f∈L_(ψ,p) (I)∩∆^0 (j_s ) ,, في الفضاء هذا يعني ايجاد رتبة افضل تقريب متشابك تقريبا للمصطلحات اعلاه .


Article
PREDICTION OF RESILIENT MODULUS MODEL FOR WEARING ASPHALT PAVEMENT LAYER

Author: Miami M. Hilal
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 4 Pages: 65-87
Publisher: University of Kufa جامعة الكوفة

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Abstract

Resilient modulus for pavement layers is a key design parameter for pavement systems and permits for determination of how the pavement system will react to traffic loadings. It can be defined shortly as elastic modulus of a material under repeated loads. Several factors have effects on the elastic modulus of the layers of asphalt pavements. The indirect repeated axial load test was carried out by using the pneumatic repeated load system (PRLS) at Transportation Laboratory at Baghdad University to test seventy two cylindrical specimens prepared by the gyratory device. SPSS program was used to predict the resilient modulus model which contains many factors like asphalt content, asphalt viscosity, air voids, surface area, and temperature. Multiple linear regression is used to build the model of resilient modulus because it is a function of more than independent variables. F statistical significance value from the results of ANOVA table is smaller than 0.05 in the predicted model then the independent variables in the predicted model explain the variation in the resilient modulus variable. The coefficient of determination (R2) is 0.886 for the predicted model which is referred to a very good relation obtained. The predicted model shows that the modulus of resilience is highly affected by variation of temperature and moderately by viscosity of the asphalt whereas the stress level, types of filler, and the asphalt content have smaller effect on resilient modulus. The predicted model shows that there is a positive relationship among the resilient modulus and the two variables viscosity and the surface area whereas the three variables temperature, asphalt content, and air voids have inverse relationship with resilient modulus. Two asphalt types (40-50) and (60-70) from Dora refinery were used; the average value of resilient modulus corresponding to asphalt grade (40- 50) is almost 21.331% times the value for asphalt grade (60-70). Three asphalt contents (optimum asphalt content, optimum asphalt content±0.5) were used; when the content of asphalt was increased from 4% to 4.5%, the average resilient modulus decreased by 2.923% whereas increasing the percent of asphalt content from 4.5 to 5 the average resilient modulus decreased by 1.737%. Two types of mineral fillers (cement and limestone) were used, and when cement was used as mineral filler, the average resilient modulus increased by 4.422% rather than using limestone as filler in the asphalt mixture. Three temperatures for test were used 10, 25, and 40 oC. The results showed that when temperature was increased from 10 to 25 ◦C, the average resilient modulus decreases by 65.738%; whereas when the test temperature was increased from 25 to 40 oC, the average resilient moduli decreased by 97.715%. The results also showed that the average resilient modulus increased by 9.69% when the stress level increased from 6.5 psi to 13 psi.


Article
Estimation of the Rock Mechanical Properties Using Conventional Log Data in North Rumaila Field

Authors: N. Jasim Al-Ameri نغم جاسم --- Wafa Al-Kattan
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2012 Volume: 13 Issue: 4 Pages: 27-33
Publisher: Baghdad University جامعة بغداد

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Abstract

Hydrocarbon production might cause changes in dynamic reservoir properties. Thus the consideration of the mechanical stability of a formation under different conditions of drilling or production is a very important issue, and basic mechanical properties of the formation should be determined.There is considerable evidence, gathered from laboratory measurements in the field of Rock Mechanics, showing a good correlation between intrinsic rock strength and the dynamic elastic constant determined from sonic-velocity and density measurements.The values of the mechanical properties determined from log data, such as the dynamic elastic constants derived from the measurement of the elastic wave velocities in the material, should be more accurate than that determined by direct strength tests with core samples. This can be attributed to the scale effect and sampling disturbances.The aim of this study was to present methods of determining measures of some mechanical properties, from available well log data (conventional sonic, density, and gamma ray) for a well in North Rumaila field.The mechanical properties include formation strength and Poisson’s ratio. For the formation strength, combined elastic modulus (Ec) and shear modulus (G) were determined. The Poisson’s ratio was determined by using three different techniques to permit the accuracy of their values. The elastic modulus, shear modulus, and Poisson’s ratio were then correlated with depth and effective stress.The results show that combined correlations are important source of the prediction of overpressure zones which represent a major problem encountered in drilling and production process.


Article
Effect of Admixture Type on Compressive Strength and Modulus of Elasticity of Rubber- Tire - Waste Concrete
تاثير نوع المضاف على مقاومة الانضغاط ومعامل المرونة لخرسانة الاطارات المطاطية المستهلكة

Author: Khalid Battal Najim خالد بتال نجم
Journal: Anbar Journal of Engineering Sciences مجلة الأنبار للعلوم الهندسية ISSN: 19979428 Year: 2007 Volume: 1 Issue: 1 Pages: 88-103
Publisher: University of Anbar جامعة الانبار

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Abstract

The presented work investigates the effect of addition admixtures (superplasticizer and polymer) to Chopped Worn-Out Tire concrete as a partial replacement of cement weight. Superpasticizer was addition by 4% and polymer (SBR) by 15%. The Chopped Worn-Out Tire (Ch.W.T.) addition to reference concrete with the three proportions as a Partial Replacement Ratio (PRR) of (25,25),(20,30),and (30,20) by volume of (sand and gravel) respectively. Three mixes were selected with above PRR for each type of admixture in additional to three mixes for Ch.W.T. concrete without admixtures and three reference mixes with admixtures without Ch.W.T. Thus, twelve mixes could be used in this investigation. Compressive strength and modulus of elasticity (static and dynamic) were tested. The test results indicated that the use of admixture led to significant improvement in concrete properties in general. Superplasticizer gave best results comparative with polymer, for example at 28 day the compressive strength of superplasticizer Ch.W.T. concrete Csp25,25 was 32.5 MPa, while compressive strength of polymer modified Ch.W.T. concrete CB25,25 was 28 MPa and compressive strength of Ch.W.T. concrete C25,25 was 21.2 MPa.

يدرس هذا البحث تأثير إضافة بعض أنواع المضافات (الملدن المتفوق والبوليمر) إلى خرسانة الإطارات المطاطية المستهلكة. حيث تم إضافة الملدن المتفوق بنسبة 4% والبوليمر بنسبة 15% من وزن الاسمنت. تم إضافة مفروم الإطارات المطاطية المستهلكة إلى الخلطات الخرسانية كجزء مستبدل من حجم الركام الخشن والناعم بثلاث نسب استبدال هي (25, 25), (20, 30) و (30, 20) (ركام خشن وناعم على التوالي). تم اختيار ثلاث خلطات بنسب الاستبدال أعلاه لكل مضاف إضافة إلى ثلاث خلطات بدون مضافات وثلاث خلطات مصدرية مع المضافات وبدون مفروم الإطارات وبذلك يكون مجموع الخلطات اثنا عشر خلطة. تم إجراء فحص مقاومة الانضغاط ومعامل المرونة ( الساكن والديناميكي), وقد أظهرت نتائج الفحص تحسن ملحوظ لخواص الخرسانة عند إضافة المضافات وكانت الأفضلية باستخدام الملدن المتفوق بشكل عام.فعلى سبيل المثال بعمر 28 يوم كانت مقاومة الانضغاط لخرسانة الإطارات الحاوية على الملدن المتفوق Csp25,25 32.5MPa بينما كانت مقاومة الانضغاط لخرسانة الإطارات المطورة بالبوليمر CB25, 25 هي 28 MPa وكانت مقاومة الانضغاط لخرسانة الإطارات بدون مضافات C25, 25 هي 21.2 MPa.


Article
Numerical Analysis Of Thin Beams Resting On Nonlinear Elastic Foundations
التحليل العددي للعتبات النحيفة المسندة على اساس غير خطي مرن

Author: Adel A. Al-Azzawi
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2010 Volume: 16 Issue: 1 Pages: 4695-4706
Publisher: Baghdad University جامعة بغداد

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Abstract

The finite difference method is used for solving the basic differential equation for the elastic deformation of a thin beam supported on a nonlinear elastic foundation. A tangent approach is used to determine the modulus of subgrade reaction after constructing a second degree equation for load-deflection diagram. Results of plate loading test of soil obtained in Iraq were used in the analysis. An iterative approach is used for solving the nonlinear problem until the convergence of the solution. The method of analysis, as programmed for a computer solution, considers the continuous elastic, nonlinear foundation to be active only when the beam is pressing against the foundation. Two examples of with simply supported beams are presented to illustrate the application of the method of analysis.

إنّ طريقةَ الفروقِ المحدودةِ تمستعملُ لحَلّ المعادلة التفاضليةِ الأساسيةِ للتشوه المرن للعتباتِ النحيفة المسندة على اسسِ مرنةِ لاخطّيةِِ. المعامل المماسي يُستَعملُ لتحديد معاملِ ردِّ فعل التربة باستعمال معادلة من الدرجةِ الثانيةِ من مخطط الحمل مع الازاحة. تم الحصول على نَتائِج إختبارِ تحميل الصفيحة لتربةِ في العراق والتي تم استخدامها في التحليلِ.تم اعتماد طريقة الحل المتكرر لحَلّ مسألة الاسس اللاخطّيةِ حتى يتقاربِ الحَلِّ. ان طريقة التحليلِ، تم برمجتها باستخدام الحاسوب، حيث يَعتبرُ الاسسسَ اللاخطّيةَ المرنة المستمرةَ الّتي سَتَكُونُ فعالةَ فقط عندما الحمل يَضْغطُ الاسس. تم انتخاب إثنان مِنْ أمثلةِ العتبات المسند اسناد بسيط لكي تُقدّمُ تَصور لكيفية تطبيق طريقةِ التحليلِ.


Article
Predicting The Relationship Between The Modulus Of Rupture And Compressive Strength Of Cement Mortar
التنبؤ بعلاقة بين معامل الكسر ومقاومة الانضغاط لمونة الاسمنت

Author: Sura A. Majeed سرى عبد الرزاق مجيد
Journal: AL Rafdain Engineering Journal مجلة هندسة الرافدين ISSN: 18130526 Year: 2009 Volume: 17 Issue: 5 Pages: 59-68
Publisher: Mosul University جامعة الموصل

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Abstract

The present paper deals with studying the effect of sand/cement (s/c) ratio and water/cement (w/c) ratio on the mechanical properties of cement mortar and to predict a relationship between modulus of rupture and compressive strength for the cement mortar. In the present work seventy two sample of cubes and prisms were tested for compressive strength and modulus of rupture. All the tests were carried out in accordance to the ASTM specification C109 using twelve different mix proportions of cement/sand ratio and water/cement ratio. From the test results and based on regression analysis a best power relation between modulus of rupture and compressive strength are proposed.Keywords: compressive strength, modulus of rupture, mortar, sand.

الخلاصةيتضمن البحث دراسة تأثير تغير نسبة الرمل الى الاسمنت وتغير نسبة الماء الى الاسمنت في مونة الاسمنت على خواصها الميكانيكية وايجاد علاقة بين معامل الكسر ومقاومة الانضغاط لمونة الاسمنت من خلال اقتراح معادلة تحكم هذه العلاقة. تضمن البحث اجراء الفحص على 72 عينة من مكعبات وموشورات مونة الاسمنت وذلك بفحص مقاومة الانضغاط ومعامل الكسر لهذه العينات. وقد تم اجراء جميع الفحوصات حسب مواصفات الجمعية الأمريكية للفحوصات والمواد ASTM باستخدام 12 مزجة مختلفة بتغيير نسبة الرمل الى الاسمنت وتغير نسبة الماء الى الاسمنت. تم استخدام نتائج الفحص من هذه الدراسة لاشتقاق معادلة تجريبية للعلاقة بين معامل الكسر ومقاومة الانضغاط لمونة الاسمنت.

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