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Article
Three-mode bifurcation of extremals in the analysis of bifurcation solutions of sixth order differential equation

Author: Hussein K. Kadhim
Journal: Journal of Education for Pure Science مجلة التربية للعلوم الصرفة ISSN: 20736592 Year: 2014 Volume: 4 Issue: 2 Pages: 149-162
Publisher: Thi-Qar University جامعة ذي قار

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Abstract

In this paper we are interested in the study of bifurcation solutions of nonlinear wave equation of sixth order of elastic beams on elastic foundations by using local method of Lyapunov –Schmidt. The normal form of the key function corresponding to the functional related to this equation has been found. Also, it was found a new geometrical description of caustic with bifurcation spreading of the critical points.

قدمنا في هذا البحث دراسة حلول التفرع لمعادلة الموجة للأنابيب المرنة الغير خطية من الدرجة السادسة بالاعتماد على أساس المرونة باستخدام طريقة ليايبونوف - شمدت المحلية في الحالة المتغايرة. تم أيجاد الصيغة القياسية للدالة الأساسية المقابلة للدالي .كذلك تم أيجاد وصف هندسي جديد للمجموعة المميزة(مخطط التفرع) مع توزيع كامل للنقاط الحرجة في المناطق المتممة للمجموعة المميزة.


Article
The Effect of Different Beverage Solutions on the Hardness of Different Acrylic Denture Teeth

Author: Ahmad W Alubaidi
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 3 Pages: 493-500
Publisher: Mosul University جامعة الموصل

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To determine the effect of different beverage solutions on the hardness of different acrylic denture teeth which are commercially available. Materials and Methods: Sixty samples were prepared from three brands of artificial teeth in this study. The posterior teeth of each brand were placed in auto polymerizing acrylic resin and the occlusal surfaces were ground flat, then immersed in distilled water (control), Pepsi, coffee and tea solutions for 30 days and then the hardness were tested using Vickers microhardness tester. Results: The RMH denture teeth materials showed the highest hardness than other denture teeth materials. Pepsi was more effective than tea and coffee in reducing the hardness of different acrylic teeth materials. Conclusions: Pepsi reduced the hardness of different acrylic teeth materials during the 30 days immersion. The hardness of RMH denture teeth materials was less affective by the different beverage solutions


Article
Spectroscopic Properties Study of Coumarine -47 Dye doped Poly Methyl Methacrylate
دراسة الخواص الطيفية لصبغة الكومرين – 47 المطعمة بالبوليمرPMMA

Authors: Lamia K.Khlaif لمياء قند خليف --- Rafah A. H. Omar رفاه عبد الهادي عمر --- Mohammad T. Hussian محمد تقي حسين
Journal: Baghdad Science Journal مجلة بغداد للعلوم ISSN: 20788665 24117986 Year: 2011 Volume: 8 Issue: 2عدد خاص بمؤتمر الفيزياء Pages: 485-494
Publisher: Baghdad University جامعة بغداد

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Abstract

A thin film of Coumarine -47 has been prepared in a chloroform solvent mixed with the same ratio of Poly Methyl Meth Acrylate ( PMMA ) at different concentrations (1x10-4 , 5x10-4 and 1x10-3 ) M . This film has been prepared by using thermal oven with temperature about (333 K) and pressure at 10-2 torr for 1 hour. The prepared thin film thickness measured using Michelson interferometer is around 0.2mm.The quantum efficiency decreased as follows (80%, 74% and 59% ) respectively. The radiative life time and fluorescent life time has been investigated as a function of dye concentration and it can be shown that they both decreased (8.57, 3.35 and 2.5) ns and (6.85, 1.97 and 1.85) ns respectively. It has been determined that the resulting overlap between the absorption spectrum and fluorescence spectrum for thin film is less than that shown for the solution, therefore stock shift will be more . From the morphological studying of the thin film it has been shown that with the increasing the concentration the defects and inhomogenity of the film increase.

تحضير غشاء رقيق من صبغة الكومارين (47) ومزجها مع البولمر (PMMA) وبنفس النسب وبمذيب الكلورفورم وبتراكيز (1x 10-3 , 5x 10 -4 , 1x 10 -4) مولاري . لقد تم تحضير الأغشية بأستخدام فرن حراري وبدرجة 333 كلفن وبضغط 10-2 تور ولمدة ساعة. وقد تم قياس سمك الغشاء بأستخدام تداخل مايكلسن حيث كان بحدود 0.2 ملم . تم حساب الكفاءة الكمية حيث كانت (59% , 47%, 80%) على التوالي . كذلك تم حساب العمر الأشعاعي وزمن الفلوره للأغشية المحضره وبالتراكيز أعلاه حيث كانت (2.5 , 3.35 , 8.57) نانوثانية وكذلك (1.85, 1.97 , 6.58) نانوثانية على التوالي . لقد وجد بأن التداخل الحاصل بين الأمتصاص والفلوره بالنسبة للأغشية هو أقل من ما عليه بالنسبة للسوائل وأن أزاحة ستوك تكون أعلى . ومن خلال دراسة الشكل المضهري للأغشية لوحضة بأن العيوب تزداد مع زيادة التركيز.


Article
An evaluation of the effect of different drinks on the color change of composan ceram composite resin (in vitro study)

Author: Dr. Zahraa Nazar Al-Wahab, B.D.S., M.Sc.* د.زهراء نزار عبد الوهاب
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2009 Volume: 6 Issue: 1 Pages: 14-19
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The ability of tooth – colored restorative material to resist stain is important because discoloration of it may result in patient dissatisfaction and additional time and expense for replacement. However, the effect of different staining agents on the color difference of resin composite restorative materials has not been completely clarified.The aim of this study was to evaluate the stainability of composan ceram resin composite upon exposure to different drinks.Forty – two disk shaped specimens (10X2mm) were prepared from composan ceram using polytetraflouroethylen mold. The specimens were divided into six groups (n=7) and stored for 7 days at 37C ْ in different types of solutions (distilled water, coffee, coffee with sugar, coffee with sugar and artificial creamer, tea, tea with sugar). Color of all the specimens was measured before and after exposure with spectrophotometer using CIE L* a* b* relative and color changes (E) were then calculated. The data were analyzed with one – way analysis of variance (ANOVA) and LSD test.There was a highly significant difference when comparing the storage agents. Coffee solution produced the most severs stain and it stained composite more than tea. When tea and coffee groups with and without sugar were compared, both groups without sugar demonstrated a higher color difference than with sugar.Coffee stained composite more than tea and the absence of sugar in coffee and tea increased color difference compared to coffee or tea with sugar.


Article
Effect of different denture cleanser solutions on some mechanical and physical properties of nylon and acrylic denture base materials

Authors: Mohamad Salman مهند سلمان --- Shatha Saleem شذى سليم
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2011 Volume: 23 Issue: special issue Pages: 19-24
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Thermoplastic non –metal clasp denture became recently the most attractive option for patients dueto its esthetic outcome and many other advantages. The chemical immersed denture cleanser is the most widelyused method by the patients to maintain clean and healthy denture , but the use of such cleanser may haveharmful effect on the denture base materials .This study aimed to evaluate some physical and mechanicalproperties of one of the thermoplastic denture base materials which is (nylon) compared with those belong toconventional heat cured acrylic and to observe the effect of two prepared denture cleansers ( 4% oxalic acid ,4%tartaric acid ) in addition to one commercial denture cleanser (lacalut dent) on the indentation hardness , flexuralstrength , flexibility , surface roughness and color stability of nylon and conventional heat cured acrylic.Materials and method: Two hundred and sixty specimens (130 nylon and 130 acrylic) were prepared ,60 specimens(30 nylon ,30 acrylic ) were used to test each of the properties mentioned above except an 80 specimens were used(40 nylon ,40 acrylic ) to test flexural strength and flexibility.Results: The result obtained in the present study showed high significant difference between nylon and conventionalheat cured acrylic in four properties which were: indentation hardness , flexural strength , flexibility and color stability,with no difference in the surface roughness .Furthermore oxalic acid and tartaric acid cleansers significantlydecrease the indentation hardness and flexural strength of conventional heat cured acrylic while lacalut dent didn’tsignificantly affect those properties of acrylic, also all the three cleansers didn’t affect the indentation hardness andflexural strength of nylon .oxalic acid and tartaric acid cleansers significantly decreased the flexibility of nylon whilelacalut dent didn’t significantly changed this property. All the three cleanser had no effect on the flexibility ofacrylic. All the three cleanser had no effect on the surface roughness or color stability of nylon and acrylic.Conclusions: It can be concluded that nylon had better flexibility and translucency than conventional heat curedacrylic while conventional heat cured acrylic had better indentation hardness and flexural strength than nylon.Regarding surface roughness the two polymers show no significant difference between them.There were an adverse effect of the prepared denture cleansers which contain isopropyl alcohol on indentationhardness and flexural strength of conventional heat cured acrylic , it decreased both those properties , so it isadvised not to use solution containing alcohol as acrylic denture cleanser also it is advised not to use it withnylon denture because it decreased its flexibility. Lacalut dent which is an oxygenating commercial denturecleanser, had no adverse effects on both polymers used in the study, so it can be used safely with them


Article
Effects of Different Disinfectant Additives on Compressive Strength of Dental Stone

Authors: Qasim A. Mohammad --- Radhwan H. Hasan --- Sadi Sh. Thiab
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2014 Volume: 22 Issue: 5 Pages: 1686-1695
Publisher: Babylon University جامعة بابل

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Abstract

Purpose: The aim of this study was to analyze the compressive strength of dental stone after incorporating different disinfectant solutions during stone models preparation. Materials and methods: A one hundred eighty die stone type IV cylindrical specimens were prepared with dimensions of 20mm diameter and 40 mm height by adding different disinfectants (Sodium hypochlorite 1% and 0.5%, Chlorhexidine 2% and 1%, glutaraldehyde 2% and 1%, Iodine 4% and 2% and a control group without additives) divided into 18 groups, 10 specimens per each group (each two groups identical of same disinfectant and same concentration). Then one of each two identical groups was tested to evaluate its compressive strength after air drying for 24 hours while the other group tested after 48 hours.Results: Chlorhexidine and glutaraldehyde in both concentrations and drying time as well as sodium hypochlorite 0.5% showed no significant difference in compressive strength compared to control group, and they showed higher values compared to sodium hypochlorite 1%. While Iodine groups in both concentrations and drying times showed the least values among all groups.Conclusions: According to the results of this study, Chlorhexidine and glutaraldehyde 1-2% as well as 0.5% sodium hypochlorite can be added to disinfect die stone casts without affecting their compressive strength, while both sodium hypochlorite at a higher concentration and iodine at any concentration are not recommended to be used for this purpose .

الهدف من هذه الدراسة هو دراسة تأثير اضافة مواد معقمة الى قوالب حجر الأسنان على قوة الكبس لهذه القوالب. تم تحضير نماذج اسطوانية من حجر الأسنان قطر القاعدة 20 ملم وارتفاع 40 ملم وبإضافة ماء كمادة قياسية او مواد معقمة بتراكيز مختلفة (كلورهيكسيدين 2% و 1% ، كلوتارالديهايد 2% و 1% ، هايبوكلوريد الصوديوم 1% و 0.5%، يود 4% و 2%) كان المجموع الكلي للنماذج المستخدمة 180 نموذج وتم توزيعها الى 18 مجموعة بواقع 10 نماذج لكل مجموعة (كل مجموعتين متماثلتين بمادة التعقيم ونسبته المئوية)، ثم تم فحص قوة كبس المجموعة الاولى من كل مجموعتين متماثلتين بعد 24 ساعة تجفيف بتركه معرض للهواء وفحص المجموعة الاخرى بعد 48 ساعة. واظهرت النتائج ان كل من الكلورهيكسيدين وكلوتارالديهايد وكذلك هايبوكلوريد الصوديوم بتركيز 0.5% ليس لها تأثير سلبي على قوة الكبس لحجر الأسنان مقارنة مع المجموعة القياسية بدون المواد المعقمة، وجميعها كانت اقوى من مجموعة هايبوكلوريد الصوديوم 1%. في حين كانت مجموعات اليود وبكلا التركيزين و بأي زمن تجفيف هي الادنى وبشكل معنوي مقارنة بجميع باقي المجموعات. يمكن الاستنتاج من هذه الدراسة انه بالإمكان استخدام الكلورهيكسيدين وكلوتارالديهايد 1-2% وكذلك هايبوكلوريد الصوديوم بتركيز منخفض 0.5% لتعقيم قوالب حجر الأسنان، في حين لا يمكن استخدام هايبوكلوريد الصوديوم بتراكيز اعلى وكذلك اليود بأي تركيز كان لهذا الغرض بسبب تأثيرهم السلبي على قوة الكبس لحجر الاسنان.


Article
Study the Spectral Properties of Coumarine -47 Dissolved in Chloroform
دراسة الخصائص الطيفية لصبغة الكومرين -47 المذابة في مذيب الكلوروفورم

Authors: Lamia Kand Kalif لمياء قند خليف --- Mohammed T. Hussian محمد تقي حسين --- Rafah Abdul Hadi Omer رفاه عبدالهادي عمر
Journal: Baghdad Science Journal مجلة بغداد للعلوم ISSN: 20788665 24117986 Year: 2014 Volume: 11 Issue: 2 عدد خاص بالمؤتمر النسوي الثاني Pages: 635-640
Publisher: Baghdad University جامعة بغداد

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Abstract

The spectral propetties (absorption and fluorescence) of Coumarine-47 laser dye have been studied. This type of laser dye belong the Coumarine family and it has dissolved in chloroform at different concentrations (1x10-5, 5x10-5, and 1x10-4 M) at room temperature. The achieved results have been pointed out to increase in the absorption and fluorescence as the concentration increased which are agreements with Beer – Lambert law. These have been also showed an expansion in the spectral range of absorption and fluorescence with a noticed shift in the direction of longer wavelength (Red-shift) with increasing concentration. The quantum efficiency of the dissolved C47 in chloroform has been computed by using the brevious concentrations and their results are as follows (69%, 63%, and 45%) respectively. The radiative and fluorescence lifetime have been also computed as given (6.47ns, 4.67ns, and 2.06ns) and (4,07ns, 3.22ns, and 1.47ns) respectively.

تمت دراسة الخصائص الطيفية ( الامتصاص والفلورة) لصبغة الكومرين – 47 الليزرية. وتنتمي هذه الصبغة الليزرية لعائلة الكومرين والمذابة في مذيب الكلوروفورم وبتراكيز 1x10-5, 5x10-5, 1x10-4) ) مولاري وبدرجة حرارة الغرفة. أظهرت النتائج زيادة في شدة الامتصاص والفلورة مع زيادة التركيز الذي يتفق مع بير – لامبرت وكذلك توسيع المدى الطيفي للامتصاص والفلورة وحدوث ازاحة لقمة طيف الامتصاص والفلورة باتجاه الاطوال الموجية الاطول (ازاحة – حمراء) مع زيادة التركيز. أذ تم حساب الكفاءة الكمية لصبغة الكومرين – 47 في مذيب الكلوروفورم وبحسب التراكيز السابقة فكانت النتائج كما يلي: ( , 45% 69% , 63% ) على التوالي وكذلك زمن العمر الاشعاعي ( 6.47, 4.67, 2,06 ) نانوثانية وزمن عمر الفلورة (4.07, 3.22, 1.47 ) نانوثانية وعلى التوالي .


Article
On Teaching Future Time to EFL Learners: Problems and Solutions
حول تدريس الزمن المستقبل لمتعلمي اللغة الإنجليزية كلغة أجنبية: مشاكل وحلول

Author: Kadhim, Naji Obeid Al-Rifaee كاظم ناجي عبيد الرفاعي
Journal: Journals eduction for girls مجلة كلية التربية للبنات للعلوم الانسانية ISSN: 19935242 Year: 2015 Issue: 17 Pages: 7-31
Publisher: University of Kufa جامعة الكوفة

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Abstract

Abstract:This study in all its overall presentation seeks to give a comprehensive account of the difficulties involved in teaching future time to students who learn English as a foreign language; and the (pedagogical) solutions humbly suggested for learners, teachers, text-book writers, linguists and psychologists since they are expected to be the best who can deal with the problems that impede the acquisition of the foreign language concepts. The work like many language teachers' works is a reaction to the frustrating state of the students who cannot use their knowledge in a real communicative situation. It spotlights the reasons of students' inefficient use of the English future structures; and projects, through a questionnaire, the most possible reasons of this problem propounding some useful techniques to overcome the problem depending on what is written in the literature of language learning and teaching. The study tackles the topic of tense and time as an entrance to investigate the nature of future structures. Apart from presenting a pedagogical view of future time references, it provides almost all the constructions used to express futurity and the indications they refer to getting use of the idea of Fleischman's time-line. The study ends with many results, findings and pedagogical suggestions. Keyword: Futurity, Pedagogy and pedagogical grammar, EFL acquisition, Tense and time, Time-Line

تعنى هذه الدراسة في مجملها بتقديم عرض للمشاكل المتعلقة بتدريس الزمن المستقبل لمتعلمي اللغة الإنجليزية كلغة أجنبية والحلول التربوية والتعليمية التي يقترحها الباحث ويضعها أمام أنظار المعنيين بهذه المشكلة من الطلبة والمعلمين وواضعي الكتب المنهجية واللغويين وغيرهم من المتخصصين بالعلوم التربوية والنفسية في محاولة لدراستها ومعالجتها. وكغيرها من الدراسات تعتبر هذه الدراسة رد فعل لحالة الإحباط التي يعاني منها هؤلاء المتعلمون الذين يبدو أنهم غير قادرين على استخدام معرفتهم اللغوية في المواقف الحقيقية للاتصال أو التواصل. وتلقي الدراسة ضوءا على الأسباب التي تقف وراء عدم قدرة الطلبة على استخدام قواعد اللغة وتراكيبها وخاصة ما يتعلق منها بموضوع الزمن في اللغة الإنجليزية كمدخل للحديث عن الزمن المستقبل والتراكيب المستخدمة للتعبيرعنه ووضع مقترحات لمعالجتها وتجاوزها. وتقدم الدراسة إجمالا لكل الصيغ والتراكيب المستخدمة للتعبير عن المستقبلية والمعاني التي تدل عليها مستفيدة من فكرة "خط الزمن" التي جاء بها Fleischman. وتنتهي الدراسة إلى العديد من النتائج والمقترحات التعليمية الأخرى.


Article
Demonstration of both Analytic and Numerical methods for Solving Volterra Integral Equations (VIE) Using Maple 13 Software Applications

Author: Haydir Ali Hassan
Journal: Journal of College of Education مجلة كلية التربية ISSN: 18120380 Year: 2012 Issue: 3 Pages: 190-203
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This paper demonstrates different analytic methods delivered by means of maple 13 algorithm for solving Volterra Integral Equation (VIE) .Three illustrative examples are given to study the differences between analytic and numerical solutions analyzing various affects on such differences.


Article
An evaluation of the effect of different solutions on the microhardness of aesthetic restoration

Author: Dr. Zahraa Nazar Al-Wahab, B.D.S., M.Sc. د.زهراء نزار
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2011 Volume: 8 Issue: 2 Pages: 106-114
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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AbstractDietary awareness is an important issue in modern society. The consumption ofcarbonated drinks is popular with the youth of today and the habit is carried over intoadulthood. One of the most important properties that determine the durability ofdental materials in the oral cavity is their resistance to dissolution or disintegrationand the longevity of dental restorations depends on the durability of the material andits properties, such as wear resistance, durability of the interface between tooth andrestoration and the level of tooth destruction.The aim of this study was to measure surface hardness of composite after storagein dry condition and after immersion in saliva and solutions that represent the populardiet.Fifty disk shaped specimens (5×2mm) were prepared from Z100 universalcomposite using polytetraflouroethylen mold. The specimens were divided into 5groups (n=10) and stored for 7 days at 37 Cْ in different types of storage conditions(dry condition, artificial saliva, coca cola, heptane and citric acid). After storage,Brinell Hardness Numbers were calculated. The data were analyzed with one – wayanalysis of variance (ANOVA) and LSD test.There was a highly significant difference when comparing the storage agents.Coca cola and citric acid solutions produced the highest reduction in microhardness ofcomposite. It was followed by heptanes, artificial saliva. The storage of specimens indry container produced the highest Brinell Hardness Numbers.Microhardness of composites stored in dry condition was the highest value,followed by artificial saliva, heptane solution, cola soft drink and citric acid . Acidsolutions have the potential to erode composite resin material and this reduction washighly significant, which means that people who consume acidic foods and drinksexcessively should be aware of their esthetic restorations.

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