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Article
Impact Strength of Maxillary Complete Dentures Fabricated From Different Heat Cured Acrylic Resin Denture Base Materials

Author: Mohammed A. Abdulla
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2012 Volume: 12 Issue: 1 Pages: 24-31
Publisher: Mosul University جامعة الموصل

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Abstract

AIMS: Evaluation of the impact strength of maxillary complete dentures fabricated from new type high impact heat-cured acrylic denture base material and comparison with other types of acrylic resin denture base materials. MATERIALS AND METHODS: Three types of materials were used in this study, high impact heat-cured acrylic resin; cross-linked acrylic resin (no cadmium); and conventional heat-cured acrylic resin. Twenty four maxillary complete dentures were fabricated to be tested and divided into three groups. Group 1, Group 2, and Group3 for high impact acrylic resin, cross-linked acrylic resin, and conventional heat- cured resin, respectively. Before testing, all specimens were stored in distilled water at 37ºC for 2 months. The impact strengths (J) of the dentures were measured with a falling-weight impact test. The impact strengths of both groups were compared by a repeated measures analysis of variance (ANOVA) and Duncan's Multiple Analysis Range Test to determine the signifi-cant difference among the tested groups at (p<0.001) level of significance. RESULTS: There is a sig-nificant difference of the mean values of impact strengths for high impact acrylic resin, cross linked acrylic resin and conventional acrylic resin denture base materials at crack initiation and complete frac-ture. The impact strength between crack initiation and complete fracture within each group was signifi-cantly different (p<0.001) for all the groups, and more energy was needed for complete fracture than that for crack initiation for the high impact strength acrylic resin. CONCLUSIONS: Maxillary com-plete dentures made from high impact acrylic resin denture base material have significantly higher im-pact strength than that of maxillary complete denture made from cross-linked and conventional acrylic resin denture base materials. Maxillary complete dentures made from cross-linked acrylic resin denture base material have significantly higher impact strength than that made from conventional acrylic resin denture base materials.


Article
Comparison between the next generation impactor and the twin glass impinge as model pulmonary drug delivery devices

Authors: Huner Kamal Omer --- Nozad Rashid Husein --- Hewa Abdulla Hamadameen
Journal: Zanco Journal of Medical Sciences مجلة زانكو للعلوم الطبية ISSN: 19955588/19955596 Year: 2019 Volume: 23 Issue: 1 Pages: 74-80
Publisher: Hawler Medical Univeristy جامعة هولير الطبية

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Abstract

Background and objective: The British Pharmacopoeia contains four apparatus for testing inhalers. Two of these are the next generation impactor, and the twin glass impinge which differs in their use. The next generation impactor apparatus should ideally have at least five stages; even though the twin glass impinge has only two stages, it is still listed in the British Pharmacopoeia. The next generation impactor is more accurate, reliable and sophisticated than the twin glass impinger. This study gives a detailed comparison of the two pieces of equipment.Methods: Carriers including mannitol, lactose monohydrate, trehalose and sucrose with active pharmaceutical ingredient; salbutamol sulphate were delivered by dry powder inhaler using the next generation impactor and twin glass impinger at a constant flow rate of 60L/min. Results: The twin glass impinge respirable fractions of the powders were higher than the next generation impactor for each carrier. As expected, mannitol powder had the lowest percentage remaining in the capsule compared to lactose monohydrate, trehalose and sucrose had the greatest percentage remaining for both inhaler devices. Conclusion: Even though both apparatus are important for in-vitro studies of drug delivery into the lungs using inhaler devices, the next generation impactor is better suited when a specific size range is required. The twin glass impinger is useful for simple inhaler testing, and the inclusion within the British Pharmacopoeia is justified.


Article
Effect of Impactor Design on Unidirectional and Woven fiber Reinforced Composites
تأثير تصميم الصادم على مواد متراكبة مقواة بالياف احادية الاتجاه ونسيجية

Author: Payman Sahbah Ahmed بيمان صحبة أحمد
Journal: Sulaimania Journal for Engineering Sciences مجلة السليمانية للعلوم الهندسية ISSN: 24101699/24156655 Year: 2016 Volume: 3 Issue: 3 Pages: 21-29
Publisher: university of Sulaimania جامعة السليمانية

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Abstract

Since impact damage resistance is such an important property for composite materials, this research is devoted to study the effect of impactor design on the impact properties of epoxy composites reinforced with unidirectional glass, unidirectional carbon, woven glass and hybrid woven (glass + carbon) fibers . This research shows changing the impactor design have no effect on impact properties of woven reinforced composites while it has a significant effect on unidirectional fiber reinforced composites, impact damage behavior of woven composites is in the form of indentation and perforation while the behavior is matrix cracking and splits along the fiber direction and fracture for unidirectional fiber reinforced composites under impact loading and finally Glass fiber reinforced composites have a better impact properties than carbon reinforced composites.

تعتبر خاصية التلف بالصدمة من الخواص المهمة جدا للمواد المتراكبة لذلك يركز هذا البحث على دراسة تأثير تصميم الصادم على خواص الصدمة لمواد متراكبة ذات اساس من الايبوكسي مقواة بالياف احادية الاتجاه من الزجاج والكاربون ،الياف نسيجية من الزجاج والياف نسيجية هجينية من الزجاج والكاربون. اظهرت النتائج ان تغيير تصميم الصادم ليس له تأثير على المواد المتراكبة المقواة بالالياف النسيجية بينما كان له تأثير كبير على المواد المتراكبة المقواة بالياف احادية الاتجاه ، كان نمط الفشل خلال فحص الصدمة في المواد المتراكبة المقواة بالالياف النسيجية بهيأة ثقب واختراق وفي المواد المتراكبة المقواة بالالياف الاحادية الاتجاه بكسر المادة الاساس والانفصال على طول الالياف وكانت مقاومة المواد المتراكبة المقواة بالالياف الزجاجية افضل بكثير من تلك المقواة بالياف الكاربون

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