Thesis (M.M.S.E.)--University of Delaware, 2008. / Principal faculty advisor: John W. Gillespie, Dept. of Materials Science. Includes bibliographical references.

Submitted by Daniella Sodre (daniella.sodre@ufpe.br) on 2015-03-04T16:32:32Z No. of bitstreams: 2 dissertacao marcio.pdf: 1723641 bytes, checksum: 60ffd3141bc44ba48bdc4ac5eb11188a (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-04T16:32:32Z (GMT). No. of bitstreams: 2 dissertacao marcio.pdf: 1723641 bytes, checksum: 60ffd3141bc44ba48bdc4ac5eb11188a (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012-02-24 / FACEPE / Esse trabalho avaliou a incorporação em argamassas de revestimento de cinzas de topo e cinzas de base, provenientes da queima de lenha de Algaroba nas lavanderias do arranjo produtivo local (APL) de confecções da região agreste pernambucano-Brasil. As cinzas foram coletadas em uma lavanderia de médio porte representativa da região, peneiradas em malha 200, avaliadas quanto as suas características físico-químicas e adicionadas em argamassa do tipo emboço, com traço 1:2:9 (cimento, cal, areia), comum nas construções da região de Caruaru-Pernambuco-Brasil. Na produção das formulações, para cada uma das cinzas, foi mantida a mesma relação água/cimento e mesma faixa de consistência para todas as argamassas, gerando formulações com adição de 10, 20, 30 e 40% em relação à massa de cimento. As formulações com adição foram comparadas com uma argamassa padrão (sem adição), utilizando a metodologia para caracterização de argamassas descrita pela ABNT. Os resultados indicaram que argamassas com adição de cinzas, quando comparadas com a argamassa padrão, apresentaram, no estado fresco, capacidade de retenção de água e densidade semelhantes, e no estado endurecido, índice de vazios, resistência mecânica, absorção de água e resistência potencial de aderência à tração sem alterações significativas. A manutenção das características das argamassas com a adição é atribuída à ação do efeito filler, que contribuiu para uma maior compacidade do sistema compensando os efeitos negativos da adição. Foi verificado, ainda, que argamassas com adição de cinzas de topo e cinzas de base apresentaram resultados equivalentes. O sucesso dos resultados gera a possibilidade de estudos futuros envolvendo a substituição parcial do cimento por cinzas de algaroba, o que significa redução de custos para a obtenção de argamassas com resistências mecânicas semelhantes à argamassa padrão, além de contribuir para a sustentabilidade ambiental minimizando o descarte aleatório desses resíduos.

Master thesis deals with highly filled particulate composite materials for dental applications. In the practical part, the dimetacrylate matrix was filled with a mixture of particles of different types and different sizes to achieve the maximum possible packing. Moreover, filler content and the influence of filler on composite material was studied. Hydrolytic stability was also tested on composite materials. The methods used to characterize composite materials were bending test, thermogravimetric analysis (TGA), differential scanning photocalorimetry (DPC), dynamic-mechanical analysis (DMA) and scanning electron microscopy (SEM). Curing of the matrix was characterized by the degree of conversion, the heat of polymerization and the polymerization rate. Furthermore the polymerization shrinkage was measured. The glass transition temperature, the dynamic modulus at 40 °C and 100 °C, the modulus of elasticity, the strength, the critical value of the stress factor and the critical energy release rate were found in the tested samples.

Charles University, Faculty of Pharmacy in Hradci Králové Department of: Pharmaceutical technology Consultant: doc. PharmDr. Jitka Mužíková, Ph.D. Student: Thao Tranová Title of Thesis: Influence of fillers' and disintegrants' type on properties of tablets with high dose drug The work engages in the study of fillers' and extragranular superdisintegrants' influence on properties of tablets with high dose drug. Two types of granulate with lactose or microcrystalline cellulose were produced in high shear granulator. Eleven tablets groups with different type and amount of superdisintegrants were prepared from the granulates. Tablets contained 2 %, 3.7 %, 5.4 % of sodium croscarmellose or 2 % and 5.4 % of crospovidone. The tested parameters of tablets were friability, hardness, disintegration time and density. Accelerated stability studies lasting 6 months at temperature of 40 řC and relative humidity 75 % were done. The tablets were evaluated after 1.5, 3 and 6 months. All tablets had adequate friability, hardness, disintegration and density at T0. Increasing concentration of superdisintegrant decreased disintegration time. Tablets containing microcrystalline cellulose and sodium croscarmellose disintegrated faster than tablets containing lactose or crospovidone. Tablets with sodium croscarmellose had...

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<p>QC 20140902</p>

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The filler-sand is a barrier between the slide gate system and the liquid metal in the steel ladle. During the casting process, the sintered sand should brake due to the ferrostatic pressure from the molten metal to initiate the teaming. This procedure is called a spontaneous opening in the casting context. However, this is not always the case, as the filler-sand that protects the sliding gate, through which the metal passes, often blocks the exit hole. This study, taking place at Uddeholm in Hagfors, Sweden, investigates the preheating, the refining and the casting process by analyzing the ladle cleaning, sand additions, amount of sand, sintering times and stirring. The aim of the study is to contribute to a better understanding concerning the reasons for complications with the spontaneous opening of the tapping hole. The study finds that the pre-sintering time has a bearing on whether the free opening is successful or not, as the longest and shortest pre-sintering times proved to have a higher rate of non-spontaneous openings. The time from when stirring is stopped to when the sliding gate is opened also correlates well, where longer times lead to more non-spontaneous openings. However, there is no evidence of any correlation between how thoroughly the filler-sand covers the hole and the occurrence of non-spontaneous openings. / Skivtärningssand agerar som en barriär mellan tappningshålet och stålsmältan i en skänk. Vid gjutning av metaller öppnas skivtärningen under skänken och skivtärningssanden som blockerar tappningshålet ska då falla till följd av stålsmältans tryck s.k. spontanöppning. Dock räcker inte alltid det ferrostatiska trycket från smältan för att ta sönder den sintrade sanden. I undersökningarna som utfördes under 5 dagar i Uddeholm i Hagfors ingick mätning av sintringstid, rengöring av varje skänk, placering och mängden skivtärningssand och omrörningen. Syftet med denna studie är att bidra till en bättre förståelse av orsakerna till icke spontanöppning vid gjutningsprocess. Studien visar att sinteringstiden under förvärmningen har den största påverkan på huruvida spontan öppningens presterande. Den längsta och kortaste sinteringstiden visade sig ha en högre grad av icke-spontana öppningar. Det finns emellertid inga tecken på något samband av hur noggrant fillersanden täcker hålet och förekomsten av icke-spontana öppningar.

<p>The main goal for a packaging is to protect the product inside. Typical packaging nowadays is made of layers of paper and barriers consisting of plastics or aluminum foil. A problem with the barrier used today is the environmental thinking. Xylophane® is an environmental friendly and biodegradable alternative to the current barrier material used in packaging. It consists of the natural carbohydrate xylan and additives. Xylophane® is an efficient barrier to oxygen, grease and aroma and can prolong the shelf life of sensitive food.</p><p>The raw material xylan is water soluble and Xylophane® can be coated on paper, board and plastics without using other solvents. A problem with the drying process is the amount of energy needed and the consumption needs to be decreased. Also, the drying capacity of the equipment to be used is often limited and the amount of water to be dried off is critical for the success of the coating process. By increasing the dry content of Xylophane® without increasing the viscosity too much, the drying process can be more effective. In this thesis, studies were made of using a filler as an additive to increase the dry content without destroying the barrier properties.</p><p>With an experimental design, a suitable relationship between the ingredients xylan (X), plasticizer (P) and filler (F) was found. Xylan is the main component and is needed to get a good oxygen barrier. The plasticizer decreases the oxygen barrier properties but is needed to make the material more flexible. The filler is positive for the barrier properties. The chosen composition was X:P = 7:3 and X:F = 1:1. Some extra experiments were made to find a reasonable value of the dry content. Dry contents around 18 % work well with temperatures at and above 45°C, but to manage to perform coating at room temperature the dry content needs to be lower.</p>