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Rosa, Pedro Henrique Papotto. "Avaliação da eficiência do antagonista seletivo de CD28, mPEG PV1-Fab´, no tratamento da uveíte autoimune experimental." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/42/42133/tde-14032015-101012/.
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A uveíte autoimune é uma doença inflamatória crônica, caracterizada pela resposta imune a antígenos oculares. É mediada por linfócitos T CD4+ com perfil TH1, e responsável por uma parcela significativa de casos de deficiências visuais e cegueira. Embora efetivos, os tratamentos disponíveis estão associados a efeitos adversos importantes. Logo, a busca de novos alvos terapêuticos mais específicos tem sido o objetivo principal no campo da imunoterapia. Nesse trabalho foi avaliada a eficiência do antagonista seletivo de CD28, mPEG PV1-Fab´(PV1), no tratamento da uveíte autoimune experimental (EAU). Camundongos tratados com PV1 exibiram menores graus de doença quando comparados a controles não tratados. Tal achado foi acompanhado de uma diminuição da ativação de linfócitos T, tanto nos olhos quanto nos órgãos linfoides periféricos desses animais. Mais ainda, o tratamento com PV1 levou a uma diminuição da população de linfócitos T reguladores e de células do tipo TH1. Portanto, concluiu-se que PV1 é eficaz no tratamento da EAU por agir em linfócitos T efetores.Autoimmune uveitis is a T-cell mediated disease that targets mainly the posterior eye pole. Similar to human uveitis, experimental autoimmune uveitis (EAU) is mostly dependent on T cells with a TH1 phenotype. Although many treatment strategies are available, most of them focus on general immunossuppression, resulting in undesirable side effects. Thus, the development of more specific therapies is the major aim in the field of immunotherapy. Here we evaluated the efficacy of mPEG PV-1-Fab´ (PV1), a specific CD28 antagonist, in the treatment of EAU. Our results indicate that PV1 blocks T cell activation by decreasing expression of different costimulatory molecules. Furthermore, PV1 treatment led to a decrease of Treg cell population in peripheral lymphoid organs. Also, IFN-g production by CD4+ cells and TH1 lymphocytes population were decreased. Altogether, our results raise this CD28 blockade strategy as a potential tool for the treatment of autoimmune disorders in the eye, and indicate that mPEG PV1-Fab acts mainly on IFN-g production and TH1 polarization.
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Lee-Montiel, Felipe, Kelly Reynolds, and Mark Riley. "Detection and quantification of poliovirus infection using FTIR spectroscopy and cell culture." BioMed Central, 2011. http://hdl.handle.net/10150/610169.
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BACKGROUND:In a globalized word, prevention of infectious diseases is a major challenge. Rapid detection of viable virus particles in water and other environmental samples is essential to public health risk assessment, homeland security and environmental protection. Current virus detection methods, especially assessing viral infectivity, are complex and time-consuming, making point-of-care detection a challenge. Faster, more sensitive, highly specific methods are needed to quantify potentially hazardous viral pathogens and to determine if suspected materials contain viable viral particles. Fourier transform infrared (FTIR) spectroscopy combined with cellular-based sensing, may offer a precise way to detect specific viruses. This approach utilizes infrared light to monitor changes in molecular components of cells by tracking changes in absorbance patterns produced following virus infection. In this work poliovirus (PV1) was used to evaluate the utility of FTIR spectroscopy with cell culture for rapid detection of infective virus particles.RESULTS:Buffalo green monkey kidney (BGMK) cells infected with different virus titers were studied at 1 - 12 hours post-infection (h.p.i.). A partial least squares (PLS) regression method was used to analyze and model cellular responses to different infection titers and times post-infection. The model performs best at 8 h.p.i., resulting in an estimated root mean square error of cross validation (RMSECV) of 17 plaque forming units (PFU)/ml when using low titers of infection of 10 and 100 PFU/ml. Higher titers, from 103 to 106 PFU/ml, could also be reliably detected.CONCLUSIONS:This approach to poliovirus detection and quantification using FTIR spectroscopy and cell culture could potentially be extended to compare biochemical cell responses to infection with different viruses. This virus detection method could feasibly be adapted to an automated scheme for use in areas such as water safety monitoring and medical diagnostics.
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Cabrera, Sotelo Julieta Gladys. "Hidrogeles de PVA-PVP conteniendo nanopartículas de plata obtenidos por radiación gamma." Universidad Nacional de Ingeniería. Programa Cybertesis PERÚ, 2009. http://cybertesis.uni.edu.pe/uni/2009/cabrera_sj/html/index-frames.html.
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Amaral, Renata Hage. "Estudo da incorporação e liberação de um extrato de algas vermelhas em membranas de hidrogel." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-16112009-145201/.
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Os hidrogéis estão dentre as matrizes poliméricas mais utilizadas em tecnologia farmacêutica em razão de sua vasta aplicação e funcionalidade, especialmente em sistema de liberação de fármacos. Tendo em vista o grande avanço nas inovações dos produtos cosméticos, tanto por meio da introdução de novos princípios ativos quanto pelas matrizes utilizadas para liberação controlada dos mesmos, o objetivo deste trabalho foi incorporar e avaliar a liberação de um princípio ativo natural, o ArctAlg®, em membranas de hidrogel, de modo a obter um dispositivo de liberação para fins cosméticos. O ArctAlg® é um extrato aquoso que possui uma excelente ação anti-oxidante, lipolítica, anti-inflamatória e citoestimulante. Foi realizado o estudo das propriedades mecânicas, físicoquímicas e a biocompatibilidade in vitro das membranas de hidrogéis de poli(vinil- 2- pirrolidona) (PVP) e poli(vinil álcool) (PVA) obtidas pela reticulação por radiação ionizante. A caracterização físico-química das matrizes poliméricas foi obtida pelos ensaios de fração gel e intumescimento e o de biocompatibilidade in vitro pelo ensaio de citotoxicidade pelo método de incorporação do vermelho neutro. No ensaio de fração gel tanto o hidrogel de PVP quanto o de PVA apresentaram um alto grau de reticulação. O hidrogel de PVP apresentou uma maior porcentagem de intumescimento em relação ao de PVA e no ensaio de citotoxicidade os hidrogéis mostraram-se atóxicos. A propriedade citoestimulante do ArctAlg® foi verificada no ensaio de citoestimulação com células fibroblásticas de pele de coelho, em que foi evidenciado um aumento de cerca de 50% das células quando em contato com 0,5% do princípio ativo. As membranas de hidrogel preparadas com 3% de ArctAlg® foram submetidas ao ensaio de liberação em incubadora a 37ºC e as alíquotas coletadas durante o ensaio foram quantificadas por cromatografia líquida de alta eficiência (HPLC). Os resultados obtidos na cinética de liberação mostraram que as membranas de hidrogel de PVP liberaram cerca de 50% do ArctAlg® incorporado e as de PVA em cerca de 30%. No ensaio de citoestimulação do ArctAlg® liberado, o dispositivo de PVP apresentou um aumento em cerca de 80% da população celular em relação ao controle do ensaio, mostrando ser o dispositivo mais indicado para ser utilizado em processos de reparação cutânea.In pharmaceutical technology hydrogel is the most used among the polymeric matrices due to its wide application and functionality, primarily in drug delivery system. In view of the large advance innovations in cosmetic products, both through the introduction of new active agents as the matrices used for its controlled release, the objective of this study was to evaluate the release and immobilization of a natural active agent, the Arct\'Alg® in hydrogel membranes to obtain a release device for cosmetics. Arct\'Alg® is an aqueous extract which has excellent anti-oxidant, lipolytic, anti-inflammatory and cytostimulant action. Study on mechanical and physical-chemical properties and biocompatibility in vitro of hydrogel membranes of poly(vinyl-2- pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) obtained by ionizing radiation crosslinking have been performed. The physical-chemical characterization of polymeric matrices was carried out by gel fraction and swelling tests and biocompatibility by in vitro test of cytotoxicity by using the technique of neutral red incorporation. In the gel fraction test, both the PVP and PVA hydrogel showed a high crosslinking degree. The PVP hydrogel showed a greater percentage of swelling in relation to PVA and the cytotoxicity test of the hydrogels showed non-toxicity effect. The cytostimulation property of Arct\'Alg® was verified by the cytostimulation test with rabbit skin cells, it was showed an increase at about 50% of the cells when in contact with 0,5% of active agent. The hydrogel membranes prepared with 3% of Arct\'Alg® were subjected to the release test in an incubator at 37°C and aliquots collected during the test were quantified by high performance liquid chromatography (HPLC). The results obtained in the kinetics of release showed that the PVP hydrogel membranes released about 50% of Arct\'Alg® incorporated and the PVA hydrogel membranes at about 30%. In the cytostimulation test of released Arct\'Alg®, the PVP device showed an increase at about 80% of cell population in relation of test control, showing to be the greater device to be used in processes of skin repair.
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Farias, Italo Fernando. "Estudo da influência da radiação gama nas propriedades mecânicas e térmicas de \"elastômeros termoplásticos\" blendas de poli (cloreto de vinila) com poli (vinil butiral)." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-11102018-083413/.
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A vasta gama de sistemas poliméricos classificados como blendas tem sido alvo crescente no meio acadêmico e científico. A possibilidade de obtenção de propriedades combinadas e múltiplas, associada a incorporações de blendas poliméricas, enriquece a condição de pesquisa abrindo assim uma extensa área de atuação. Neste trabalho foi proposto o estudo de mistura de composto de poli (cloreto de vinila) plastificado com resíduo de poli (vinil butiral), proveniente de laminados para produção de para-brisas da indústria automotiva, bem como a investigação do efeito da irradiação gama com dose absorvida de 25 kGy, 30 kGy e 40 kGy, controlado com uso de dosímetro de PMMA e taxa de dose equivalente de 0-10 kGy.h-1. Foram analisadas variações das propriedades mecânicas e térmicas das amostras antes e após exposição à radiação gama. As formulações foram constituídas em diferentes concentrações: composto de PVC-C, resíduo de PVB-R, PVC-C/PVB-R 90/10, PVC-C/PVB-R 50/50 e PVC-R/PVB-R 50/50. O composto de poli (cloreto de vinila) foi formulado e aditivado, apresentando comportamento de um elastômero termoplástico, produto flexível. Foram incorporadas aparas moídas de poli (vinil butiral), provenientes de laminados para produção de para-brisas. Ambos os materiais foram incorporados em extrusora granuladora tipo rosca simples e submetidos ao processo de calandragem para efetivação da mistura e formação de mantas plásticas. As mantas foram irradiadas em um reator multipropósito de 60Co e caracterizadas para verificação das propriedades mecânicas e térmicas. Para tanto, as blendas após exposição à radiação gama apresentaram propriedades mecânicas e térmicas intermediarias as propriedades dos seus componentes, mostrando-se um material resistente e de baixo custo. Por meio da microscopia eletrônica de varredura obteve uma redução nos vasos interfaciais mostrando um aumento na capacidade de percolação do PVB na matriz de PVC, favorecendo suas propriedades físicas.The wide range of polymer systems classified as blends has been increasingly targeted in the academic and scientific milieu. The possibility of obtaining multiple and combined properties, combined with the incorporation of polymer blends, enriches the research condition, thus opening up an extensive area of performance. In this work the study of the poly (vinyl butyral) plasticized polyvinyl chloride mixture from laminates for automotive windshield production was investigated, as well as the investigation of the effect of gamma irradiation with absorbed dose of 25 kGy, 30 kGy and 40 kGy, controlled with use of PMMA dosimeter and equivalent dose rate of 0-10 kGy.h-1. Variations of the mechanical and thermal properties of the samples were analyzed before and after exposure to gamma radiation. The formulations were constituted in different concentrations: PVC-C compound, PVB-R residue, PVC-C/PVB-R 90/10, PVC-C/PVB-R 50/50 and PVC-R/PVB-R 50/50. The polyvinyl chloride compound was formulated and added, exhibiting the behavior of a thermoplastic elastomer, a flexible product. Poly (vinyl butyral) ground chips were produced from laminates for the production of windshields. Both materials were incorporated in a single-thread granulator extruder and submitted to the calendering process to effect the mixing and formation of plastic blankets. The blankets were irradiated in a 60Co multipurpose reactor and characterized for verification of mechanical and thermal properties. In order to do so, the blends after exposure to gamma radiation presented mechanical properties and intermediate thermal properties of their components, showing a resistant material and low cost. By means of the scanning electron microscopy it obtained a reduction in the interfacial vessels showing an increase in the percolation capacity of the PVB in the PVC matrix, favoring its physical properties.
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Hong, Sathapanaroth Satha. "Modélisation de dispersions eau-VCM-PVC en présence de tensio-actifs macromoléculaires à base de PVA." Mulhouse, 2005. http://www.theses.fr/2005MULH0784.
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L'objectif de cette étude est de préparer et de caractériser des nanoparticules à base d'alcool polyvinylique (PVA) qui pourront par la suite être utilisées comme stabilisants particulaires de type "Pickering" lors de la polymérisation en suspension du chlorure de vinyle (VCM). Du fait de la toxicité du VCM, un solvant modèle, le chlorobutane (CIBu), est utilisé à la place du VCM dans l'étude de l'émulsion de départ. Nous avons ainsi montré qu'il est possible d'o6tenir, par un procédé de coacervation, des dispersions aqueuses à base de PVA formées de nanoparticules colloïdales monodisperses en taille, de diamètre compris entre 150 et 300 nm. Les différentes techniques de caractérisation utilisées ont permis de mettre en évidence une structure sphérique de type "coeur-couronne" des nanoparticules dont la composition joue un rôle important sur leur capacité à stabiliser l'émulsion CIBu/eau, une stabilisation de type "Pickering" étant plus favorable qu'une stabilisation purement stériqueThe objective of this study was to prepare and to characterize colloidal particles based on polyvinyl alcohol (PVA) which could be used as particie stabilizers, called "Pickering" stabilizers, in suspension polymerization of vinyl chloride (VCM). Due to VCM toxicity, a model solvent, butyl chloride (CIBu), is used instead of VCM in the initial emulsion study. We have shown that it is possible to obtain, with a coacervation technique, aqueous dispersions based on PVA formed by colloidal particles monodispersed in size, with a diameter between 150 and 300 nm. Different characterization techniques, enabied to demonstrate a spherical "core-shell" structure of the nanoparticles which composition plays an important role on their ability to stabilise CIBu/water emulsion, a "Pickering" stabilisation being better than a pure steric stabilisation
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AMARAL, RENATA H. "Estudo da incorporacao e liberacao de um extrato de algas vermelhas em membranas de hidrogel." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9445.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Schubert, Martin Verfasser], Marcus A. [Akademischer Betreuer] [Glomb, and Thomas [Akademischer Betreuer] Simat. "Untersuchungen zum Einsatz von PVI, PVP bei Bier und Wein / Martin Schubert. Betreuer: Marcus Glomb ; Thomas Simat." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2011. http://d-nb.info/1025231163/34.
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Shapla, Tanweer J. "INFERENCE OF ATTRIBUTABLE RISK FOR MULTIPLE EXPOSURE LEVELS UNDER CROSS-SECTIONAL SAMPLING DESIGN." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1148489335.
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Junkunlo, Kingkamon. "Regulation of hematopoiesis in the freshwater crayfish, Pacifastacus leniusculus : role of transglutaminase." Doctoral thesis, Uppsala universitet, Jämförande fysiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-327921.
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The freshwater crayfish, Pacifastacus leniusculus, has been used as a model for studying hematopoiesis or blood cell production or hematopoiesis and immunity. The work of this thesis aims to investigate the impact of factors such as ROS signaling, Ast1, and the PVF/PVR signaling pathway in controlling stem cell behavior during hematopoiesis and specifically the role of the crosslinking enzyme transglutaminase (TGase) in regulation of hematopoiesis. The role of ROS in crayfish hematopoiesis was characterized by using the antioxidant named NAC to inhibit ROS production. Low ROS level resulted in a prolonged decrease in hemocyte numbers and a combined injection of LPS and NAC caused a slower rate of new hemocyte production. A low ROS level in cell cultures supplemented with crude Ast1 was found to inhibit cell spreading and a high extracellular TGase activity was detected on the surfaces of APC and HPT cells. We suggest that ROS serves as a prime signal to control proliferation and differentiation of progenitor cells by affecting extracellular TGase activity. We reported an inhibitory effect of Ast1 on TGase enzyme activity and on its crosslinking activity and consequently Ast1 affects the clot formation and thus coagulation by inhibiting the crosslinking activity of the TGase enzyme. Secretion of the clot protein (CP) and the production of CP filament network between spreading cells were observed in HPT cell cultures in vitro. In the presence of CP together with Ast1 in 3D-collagen-I cultures, HPT cells were found to be more elongated and they formed chains of cells throughout the surrounding matrix. In the HPT tissue, CP was located around the HPT cells or around the lobules of HPT, and thus, CP was demonstrated to be a part of ECM and to possibly function together with collagen in generating a suitable environment for HPT progenitor cells. The inhibition of PVF/PVR downstream signaling pathway by Sunitinib malate resulted in a dramatic change of cell morphology and induction of an increase cell surface area during cell culture. The addition of crude Ast1 into the cell cultures in vitro enhanced this effect. Consequently, cell migration was stimulated and a high extracellular TGase activity on HPT cell surface was found after this inhibition. In conclusion, the work in this thesis provides new insight in understanding the role of the extracellular matrix (ECM) and extracellular TGase activity in controlling stem cell activity.
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Rodrigues, Isadora Reis. "Síntese e caracterização de redes poliméricas a base de quitosana com PVP e PVA para aplicação na liberação controlada de fármacos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/8349.
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Neste trabalho foram desenvolvidos hidrogéis na forma de membranas a base de quitosana (QUI) com polivinilpirrolidona (PVP) ou poli (álcool vinílico) (PVA), usando como agente de reticulação glutaraldeído, para obtenção de redes poliméricas semiinterpenetrantes e redes poliméricas híbridas, respectivamente. Os hidrogéis foram sintetizados em diferentes razões de PVP/QUI e PVA/QUI (%p/p) com duas concentrações distintas de glutaraldeído, visando estudar a influência da composição química nas propriedades dos materiais. Os hidrogéis foram caracterizados através das técnicas de FTIR, DSC, TGA e DMA. O grau de inchamento, ou capacidade de absorção de água dos hidrogéis foi avaliada em testes de inchamento com soluções aquosas de pH 3, 7 e 9. Os hidrogéis foram avaliados por espectroscopia de impedância eletroquímica para avaliar a sua condutividade iônica. A capacidade de armazenamento de amoxicilina pelos hidrogéis e a liberação controlada desta, foi avaliada por espectrofotometria UV e por transporte passivo em uma célula de difusão. O grau de inchamento e o transporte de amoxicilina dos hidrogéis de PVP/QUI e PVA/QUI dependem da composição destes e também do pH do meio. A determinação da condutividade iônica das membranas PVP/QUI e PVA/QUI mostrou-se depende da composição dos hidrogéis. Resultados promissores foram obtidos quanto a condutividade iônica dos hidrogéis e a liberação controlada de amoxicilina.In this work hydrogels based on chitosan with polyvinylpirrolidone (PVP) or poly (vinyl alcohol) (PVA) were obtained, using glutaraldehyde as a crosslinking agent in order to produce semi-interpenetrating polymer networks or hybrid polymer networks. The hydrogels were synthesized using different PVP/chitosan and PVA/chitosan ratios and different glutaraldehyde concentrations aiming to observe the influence of chemical composition on the hydrogels properties. The hydrogels were characterized by FTIR spectroscopy, DSC, TGA, DMA, swelling ratio and impedance spectroscopy. Furthermore, the incorporation of amoxicillin into the hydrogels was carried out and for drug release studies under different pH conditions were realized. It was observed that the hidrogel swelling ratio and amoxicillin delivery of PVP/chitosan and PVA/chitosan hydrogels were influenced by the composition and pH. The impedance studies revealed that the ionic conductivity of membranes is influenced by their composition.
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Aubin, Antoine. "Optimisation des opérations de séchage dans la chaîne de fabrication du PVC en poudre. Expérimentation, simulation et modélisation." Thesis, Toulouse, INPT, 2014. http://www.theses.fr/2014INPT0048/document.
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Lors de la production du PVC en poudre, après l’étape de polymérisation en suspension, on obtient une bouillie constituée d’un mélange de grains macroporeux de taille comprise entre 100 et 200 μm et d’eau. L’étape de centrifugation permet la séparation de la phase liquide exprimable et la production d’un milieu poreux humide appelé « gâteau ». La teneur en eau du gâteau ainsi formé est de 30 % de la masse du produit anhydre. Le séchage du gâteau de filtration se fait dans un séchoir Flash (séchoir pneumatique) couplé à un séchoir à lit fluidisé. Cette opération, très gourmande en énergie et donc très impactante en termes d’émission de Gaz à Effet de Serre (GES), représente 30% du coût de fabrication et 50% des émissions de CO2. Ce travail, réalisé dans le cadre d’une collaboration avec le groupe INEOS ChlorVinyls, est consacrée à l’étude de l’étape de séchage thermique, et à la réalisation d’outils expérimentaux et théoriques permettant d’optimiser le fonctionnement et de réduire la consommation énergétique de cette étape. Dans ce but, l’étude du séchage du PVC est réalisée à l’échelle d’une particule isolée d’une part, et à l’échelle du procédé industriel d’autre part. La détermination expérimentale de la cinétique de séchage est effectuée en immergeant une quantité de produit humide (gâteau de filtration) dans un lit fluidisé de grosses particules inertes et chaudes (billes de verre), et permet d’étudier l’influence de différents paramètres sur la cinétique d’évaporation. Les résultats ont montré que cette cinétique est limitée par les processus d’évaporation à l’intérieur et à la surface des particules. Du point de vue théorique, un modèle dont le principe repose sur les bilans de matière et de chaleur à l’échelle du grain de PVC, couplés aux bilans sur le séchoir à lit fluidisé, a été élaboré. La comparaison des résultats de ce modèle avec les résultats expérimentaux a permis de vérifier la validité de la loi cinétique ainsi établie. Finalement, cette loi a été intégrée dans un modèle simulant le séchoir pneumatique industriel. Les résultats théoriques sont comparés à des mesures réalisées sur un séchoir pneumatique industriel équipé de capteurs de pression, d’humidité et de température. Les résultats de cette étude ont permis de proposer une nouvelle stratégie de régulation du séchoir pneumatique ainsi que des modifications du procédé, ne nécessitant pas d’investissement. L’ensemble de ces propositions a permis de réduire d’environ 30% la consommation énergétique pour un rendement de séchage équivalentIn a PVC powder production line, the step of suspension polymerization produces a mixture of macroporous particles and water, called “slurry”. The mean particle size varies between 100 and 200 µm. The centrifugation step eliminates most of water content and produces a wet porous medium called “cake”. The water content of the cake is about 30% of the dry product mass. Drying operations take place in a Flash dryer (pneumatic dryer) coupled with a fluidized bed dryer. These operations, which consume a lot of energy and produce greenhouse gas, represent 30% of the production cost and 50% of the CO2 emissions. This work, realized in collaboration with INEOS ChlorVinyls group, is devoted to the study of the thermal drying step and to the realization of experimental and theoretical tools in order to optimize and reduce the energy consumption of this step. The study of the drying step is realized, on the one hand, at the particle scale and, on the other hand, at the industrial dryer scale. The particle scale drying kinetic is obtained by immersing a sample of wet product in a fluidized bed of warm inert particles (glass beads), and enables to study the influence of different parameters on the evaporation kinetic. The results have shown a limitation of this kinetic by the evaporation process both inside the particles and on their outer surface. In a theoretical way, a model based on mass and heat balances at particle scale coupled with fluidized bed balances, has been developed. The kinetic law developed is validated by the comparison between the results of this model and the experimental results. Finally, this law is integrated in a model simulating the industrial pneumatic dryer. The theoretical results are compared to the measurements realized on an industrial pneumatic dryer, equipped with several pressure, humidity and temperature sensors. The results of this study lead to the proposition of a new regulation strategy for the pneumatic dryer and some zero-investment modifications of the process. All these propositions enable an energy consumption reduction of 30%
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Савчук, Б. П. "PVC Compounds." Thesis, Київський національний університет технологій та дизайну, 2017. https://er.knutd.edu.ua/handle/123456789/7389.
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Velazquez, Alberto. "Microstructure and thermal stability of PVC and chemically modified PVC." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74243.
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This thesis describes a study of the effect of microstructure on the thermal stability of poly(vinyl chloride), PVC, vinyl chloride-ethylene, VC-E, and vinyl chloride-propylene, VC-P, copolymers obtained by chemical modification of PVC. The VC-E copolymers, with an ethylene content between 1.1 and 21 mole %, are random copolymers with approximately the same degree of polymerization as the original PVC. A decrease in the number of defect sites is observed with extent of reaction. Concomitantly, the syndiotacticity increases. The VC-P copolymers, with propylene content of ca. 0.1%, also have less labile chlorines than the homopolymer since these react preferentially.The thermal stability of solid state samples was studied, at temperatures between 150 and 190$ sp circ$C under a nitrogen atmosphere, using a conductimetric method to measure evolved HCl. The thermal stability of the modified samples is improved relative to that of the initial homopolymers. For the VC-E copolymers, a linear relationship is observed between the rates of degradation and the number of labile chlorines, total double bonds and the degree of syndiotacticity. The role of syndiotacticity on the thermal degradation behavior is confirmed in results obtained with two unmodified PVC samples, with a similar number of defect sites but different syndiotacticity. The more syndiotactic resin shows a higher thermal stability. The average polyene sequence length is independent of the ethylene concentration. Thus, the ethylene units do not interfere in the development of polyene sequences.
The VC-P copolymers also show improved thermal stability as compared to that of PVC. However, the improvement is less than that of the VC-E copolymers, due to a lower extent of substitution of labile sites.
PVC previously saturated with HCl shows a markedly increased rate of degradation reflecting the autocatalytic role of HCl. For the PVC coated samples, a decrease in the degradation rates with decreasing PVC film thickness is observed due to more efficient removal of HCl. The PVC mixtures with Chromosorb W or silica gel exhibit a decrease in the dehydrochlorination rate constants with decreasing PVC content. The inert substrate acts as a diluent and avoids agglomeration of the samples and thus facilitates the removal of HCl.
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Lindberg, My, and Frida Lindstrii. "PVK IN SITU." Thesis, Malmö högskola, Fakulteten för hälsa och samhälle (HS), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-26113.
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Lindberg M & Lindstrii F. PVK in situ. En observationsstudie av följsamhet tillriktlinjer gällande skötsel, dokumentation vid fixeringsförband,komplikationssymptom samt tid in situ. Examensarbete i omvårdnad 15högskolepoäng. Malmö högskola: Fakulteten för hälsa och samhälle, institutionenför vårdvetenskap, 2014.Bakgrund: perifer ven kateter (PVK) är ett mycket vanligt ingrepp inomsjukvården som medför risker för kateterrelaterade komplikationer. I Sverige ärdet främst sjuksköterskans uppgift att hantera vården kring PVK. Vårdhandbokenhar som uppgift att säkerhetsställa en god säker vård genom att publiceralättillgängliga riktlinjer för olika moment inom sjukvården. Genom att följavårdhandbokens riktlinjer avseende PVK kan riskerna för komplikationer minska.Syfte: beskriva följsamhet till vårdhandbokens riktlinjer gällande skötsel av PVK,dokumentation vid fixeringsförband, byte vid komplikationssymptom samt attbeskriva tid in situ av PVK på vårdavdelningar.Metod: en observationsstudie genomfördes på ett större och ett mindre sjukhusi södra Sverige. Datainsamling gjordes under två veckors tid med hjälp av ettvaliderat och reabilitetstestat instrument, PVC – Assess, och ett eget framtagetprotokoll av författarna. Totalt insamlades 64 PVK observationer.Resultat: följsamheten till vårdhandbokens riktlinjer var inte tillfredsställande vidmajoriteten av variablerna i PVC-Assess, dokumentation vid fixeringsförbandetoch tid in situ.Slutsats: studien har metodologiska brister som medför att resultatets trovärdighetblir låg. Dock antyder resultatet på att det finns brister i följsamheter kringriktlinjer avseende PVK.Lindberg M & Lindstrii F. PVC in situ. An observational study of adherence towards guidelines regarding the management, documentation at fixationdressings, symptoms of complications and the time in situ. Degree project in nursing 15 credit points. Malmö University: Faculty of health and society, Department of care science, 2014.Background: peripheral vein catheter (PVC) is a very common procedure in healthcare that involves risks for catheter-related complications. In Sweden, the management and care of PVC is primary performed by nurses. The handbook for healthcare’s task is to provide a good and safe care by publishing accessible guidelines on various topics in healthcare. By following the handbook for healthcare’s guidelines regarding PVC the risks for complications can be reduced. Aim: describe adherence to the handbook for healthcare’s guidelines regarding the management of PVC, documentation at fixation-dressings, changing by complication-symptoms and to describe time in situ of PVC in wards.Method: an observational study was conducted on a larger and a smaller hospital in southern Sweden. Data collection was done in two weeks’ time with the help of a validated and reliability-tested instrument, PVC - Assess, and a protocol developed by the authors. Total of 64 PVC were observed.Results: adherence to the handbook for healthcare’s guidelines were not being guaranteed by the majority of the variables in PVC-Assess, documentation at fixation dressing and the time in situ.Conclusion: the study has methodological shortcomings that lowers the results credibility. However, the results suggests that there is still a lack of compliance regarding PVC-guidelines.
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Searle, J. R. "Titanium dioxide pigment photocatalysed degradation of PVC and plasticised PVC coatings." Thesis, Swansea University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638788.
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Due to its ubiquitous presence in paints of all colours, titanium dioxide represents the primary pigment used in Organically Coated Steel (OCS) for construction applications. However the semi-conducting nature of TiO2 translates into a possibility of inducing photodegradation when exposed to Ultra Violet (UV) radiation such as that present in sunlight. Initial research concentrated on developing a test procedure of the photoactivity of these pigments within a PVC binder. Model coatings, using pigments of known performance, have been tested to evaluate the success of this rapid test technique and excellent correlation has been shown. Building on this, Chapter 4 details a unique cell that has been designed, constructed and tested resulting in a more versatile testing environment. This cell has been used to examine the photostability of 4 commercially available pigments while present within a standard emulsion paint binder. Chapters 5 and 6 detail work performed on Plasticised PVC paint films and the resultant effects this has on the kinetics of photodegradation as monitored via the evolution of CO2. Also incorporated into this design is the ability to identify and quantify volatile organic components that are evolved during the degradation process, thus providing information regarding the photodegradation mechanism occurring within the film. It has been found that in these model films, the addition of plasticiser increases the rate of photogenerated CO2 and also produces volatile components that can be directly related to the parent plasticiser molecule. There is some evidence to suggest that for certain plasticisers, a sacrificial protection mechanism is at work, resulting in increased CO2 evolution but decreased attack on the binder matrix. Finally in Chapter 7, a number of complimentary techniques are employed to assess the effect that TiO2 photocatalysed PVC degradation has on the underlying substrate material. The techniques include electrochemical impedance spectroscopy (EIS), electro-generated chemiluminescence (ECL) and 3-D scanning vibrating electrode technique (3-D SVET). Photodegradation leads to porosity development in coatings and eventual through coating penetrative defects lead to corrosion.
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Vess, Lora Elizabeth. "The politics of PVC /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2007. http://hdl.handle.net/1794/6195.
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Thesis (Ph. D.)--University of Oregon, 2007.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 252-277). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Joss, Victoria. "Surface treatments of PVC." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398489.
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Greer, Emma. "Mechanistic studies on Ph1." Thesis, University of East Anglia, 2011. https://ueaeprints.uea.ac.uk/35555/.
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Silva, Carolina Branco Alves. "Equity research - PVH Corp." Master's thesis, Instituto Superior de Economia e Gestão, 2019. http://hdl.handle.net/10400.5/19482.
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Mestrado em FinançasO objetivo desta dissertação é calcular o valor do capital próprio da empresa PVH, Corp. no final do ano de 2019. Este relatório segue o formato recomendado pelo CFA Institute. Foi realizada uma análise detalhada à situação financeira da empresa e à indústria onde esta está inserida, seguidas de uma avaliação FCD e por Múltiplos. A avaliação segundo os FCD resultou num preço por acção de $104.30, que representa um ganho de 18.90%, quando comparada com o preço corrente de $87.72. A avaliação por múltiplos resultou num preço de $98.89, 12.73% acima do preço corrente. Foi realizada uma extensa Análise de Sensibilidade de modo a compreender os impactos de múltiplas variáveis no preço final da acção, e os resultados indicam que este será à volta de $114.62. Este valor representa um ganho de 30.67%, quando comparado com o preço corrente. Para complementar a Análise de Sensibilidade, foram feitas simulações Monte Carlo para melhor compreender o impacto causado pelo WACC Terminal e pela Taxa de Crescimento no valor da acção. Os resultados apontam para um preço médio por acção de $111.93, representando um ganho de 27.60%, suportando o resultado da avaliação dos FCD. A probabilidade de uma recomendação de compra de acções ronda os 85%. A conclusão desta dissertação é portanto o aconselhamento à compra de ações da empresa.
The purpose of this dissertation is to determine PVH, Corp. equity value at the end of 2019. The main motivation behind picking PVH, Corp. was the insights and expertise gain in the Fashion Luxury Apparel Industry throughout a group work performed in the curricular unit of Equity Research. This report follows the research report format recommended by the CFA Institute. It was performed a detailed analysis on the company financials and industry sector followed by a DCF and Multiples Valuation. The DCF resulted in a share price of $104.30, that represents a upside potential of 18.90% when compared to the current price of $87.72. The multiples valuation resulted in a share price of $98.89, 12.73% above the current price. An extensive Sensitivity Analysis was also performed to access the impact of multiple variables, and the result point to a Price Target rounding $114.62. This value represents an upside potential of 25.16%, when compared to the current price. To complement the sensitivity analysis, a Monte Carlo Simulation was also performed to better access the impact caused by the Terminal WACC and Terminal Growth Rate on Price Target. Results showed a mean Price Target of $111.93, representing an Upside Potential of 30.67%, which is near the price target computed by the DCF valuation. The probability of a BUY recommendation is close to 85%. Thus, the outcome of this dissertation is a Buy Recommendation.
info:eu-repo/semantics/publishedVersion
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Merriman, Carolyn. "Peripheral Vascular System (PVS)." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/8533.
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Wuyts, Shirley Lynne. "SAR processing using PVM." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/21763.
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Bibliography: pages 120-121.This thesis explores various methods of using PVM (Parallel Virtual Machine) to improve the speed of processing a SAR (Synthetic Aperture Radar) image. A network of heterogeneous machines were set up as the basis of the parallel virtual machine. SAR processing software was written for testing the PVM. The software performed simplified range and azimuth compression on simulated SAR images of a point target The theory and results were examined as part of the thesis. Complications such as range curvature, range migration and range dependent focusing were not addressed.
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Vess, Lora Elizabeth 1972. "The Politics of PVC." Thesis, University of Oregon, 2007. http://hdl.handle.net/1794/6195.
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xv, 277 p. A print copy of this title is available from the UO Libraries, under the call number: SCIENCE TP1180.V48 V46 2007This dissertation examines the political, scientific, social, environmental, and health debates surrounding the use of polyvinyl chloride (commonly called vinyl), a plastic many public health advocates and activists contend has a toxic lifecycle with deleterious human and ecological impacts at every stage. Using extensive documentary research and in-depth interviews, I answer a basic question: how and why have major stakeholders politicized PVC in recent decades? I find the strength of the anti-PVC movement lies largely in its broad based constituency: it includes professionals within the health care and green building industries, as well as labor unions and environmental health advocates. However, I raise critical questions about the movement's strategy of situating itself as a market-based movement where limited analysis is given to the greater environmental and health impacts of the health care and building industries as a whole.
Adviser: Gregory McLauchlan
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Macedo, Wesley. "PS1 / MoMA-PS1: a transformação de um edifício em espaço expositivo de arte." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/16/16138/tde-29102015-094943/.
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A pesquisa aborda o movimento dos espaços alternativos de arte contemporânea observado em Nova Iorque (EUA), nas décadas de 1960 e 1970, com foco no PS1 lnstitute of Contemporary Ar/, inaugurado em 1976. Embora sua criação abarque características latentes do modelo dos espaços alternativos, logo indicou uma progressão inevitável rumo à institucionalização desses espaços, cujos padrões administrativos se afastaram de suas concepções e ideias mais experimentais. Ainda que alguns autores classifiquem o PS1 como antimuseu\", não tardou para que este centro de arte contemporânea fosse incorporado ao tradicional Museu de Arte Moderna de Nova Iorque - MoMA-NY. Com isso, o PS1 adentra o mainstream da arte sob o título de MoMA-PS1, oficialmente em 2010. A abordagem discorre sobre o objeto de estudo como resultado de manifestações artísticas que contribuem na mudança de convenções estabelecidas no sistema da arte. Essas manifestações incluem a prática de apropriação da arquitetura como tema da criação artística. Assim, este trabalho contribui para fomentar novas interpretações na análise crítica do projeto de arquitetura para espaços expositivos de arte, instalados em edifícios não projetados para um fim museológico.The research addresses the movement of alternative spaces for contemporary art seen in New York (USA), in the 1960s and 1970s, focusing on the PS11nstitute of Contemporary Art, opened in 1976. Though his creation comprises /atent characteristics of the model of the alternative spaces, soon it indicated an inevitable progresswn bound for the institutionalization of these spaces, whose administrative standards have drifted away from their conceptions and more experimental ideas. Even though some authors c!assify the PS1 as \"antimuseum \", soon this contemporary art center was incorporated into the traditional Museum of Modem Art of New York- MoMA-NY. Thus, the PS 1 enters the mainstream of art under the title of MoMA-PS1, officially in 201 O. The approach discusses the object of study as a result of artistic events that contribute to the change of conventions established in the art system. These events include the practice of architecture appropriation as theme for artistic creation. 7his work contributes to fostering new interpretations on critica/ analysis of the architectural project for exhibition spaces of art instal/ed in buildings not designed for Museum purpose.
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Grizzo, Leandro Henrique. "Desenvolvimento de concentrados de PVC reforçados com fibras de vidro longas (LF-PVC) para reforçar compostos de PVC rígido moldados por injeção." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/723.
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This work presents a study and development of long glass fiber PVC pellet concentrate (LF-PVC) manufactured by extrusion similar wire coating technique to reinforce pelletized rigid PVC compounds to produce injection molding LF-PVC composites. The incorporation of LF-PVC in rigid PVC compound exhibited mechanical benefits mainly in tensile modulus, flexural modulus and notched impact strength. Injection molding LF-PVC composites with 20 wt% of fiberglass presented tensile and flexural modulus 90% higher than unreinforced rigid PVC; Izod and Charpy notched impact strength 13% and 40% higher than unreinforced rigid PVC, respectively. The reinforcement of rigid PVC with LF-PVC presented slight damage in heat distortion and Vicat temperatures. 20wt% fiberglass PVC composites presented around 10% lower than unreinforced rigid PVC because LF-PVC reinforcement presented little quantity of plasticizers and majority of low molecular weight PVC resin. The innovative technique developed by Grizzo in a preliminary work [1; 2] to incorporate long glass fiber in rigid PVC compound was optimized because the LF-PVC pellets produced presented lower quantity of plasticizer, adequate fiberglass roving with suitable coupling agent (sizing) for PVC and a fiberglass roving tex (g/km) with excellent cost. In summary the reinforcement of injection molding rigid PVC compound with LF-PVC compounds produced unsatisfactory mechanical performance of LF-PVC composites, although that allowed them to compete to long glass fiber polypropylene and polyamide composites in injection molding technical parts under room temperature. Also LF-PVC composites allowed improve usual PVC applications such as connections to reduce thickness or rise dimensional, for example diameter and length, which was not possible before. The last, there are potential applications for LF-PVC composites to be used in special pressurized connections to replace internal metallic reinforcement, and in faucets and other bathroom devices for metal replacement.
Neste trabalho é descrito o estudo e o desenvolvido de um composto granulado de PVC reforçado com fibras de vidro longas (LF-PVC), produzidos através de uma técnica de extrusão similar a de recobrimento de fios, para ser utilizado na fabricação de compósitos PVC/fibras de vidro moldados por injeção. A incorporação dos grânulos LF-PVC num composto de PVC rígido apresentou benefícios principalmente quanto à rigidez sob tração e flexão e à resistência ao impacto. O compósito de PVC reforçado com 20% em massa de fibras de vidro longas apresentou aumento de 90% nos valores de módulo de elasticidade sob tração e sob flexão, e um aumento de 13% e 40% na resistência ao impacto Izod e Charpy com entalhes, respectivamente. O reforçamento do composto de PVC rígido com os grânulos LF-PVC apresentou redução moderada nas temperaturas de deflexão térmica (HDT) e de amolecimento Vicat, sendo obtida uma redução de 10% para o compósito reforçado com 20% de fibras de vidro longas, em virtude da presença de uma pequena quantidade de plastificante e do uso de uma resina de baixa massa molar na formulação de PVC utilizada na fabricação do grânulo LF-PVC. A técnica inovadora de incorporação de fibras de vidro longas em compostos de PVC, desenvolvida por Grizzo em trabalho anterior [1; 2], foi aperfeiçoada através da redução da quantidade de plastificante utilizado no composto do grânulo LF-PVC; do uso de um roving de vidro com sizing específico para PVC; e do uso de um roving de vidro com um tex (g/km) de excelente custo. De um modo geral o reforçamento do composto de PVC rígido com os grânulos LFPVC apresentou desempenho mecânico considerado não satisfatório, porém com possibilidade dos compósitos PVC/fibras de vidro de competir com os compósitos de polipropileno e poliamida reforçados com fibras de vidro em peças técnicas moldadas por injeção sob condições normais de temperatura. O reforçamento também possibilita a melhoria de produtos convencionais de PVC, como conexões, através da redução de espessura e da ampliação de dimensionais, como diâmetros e comprimentos, não possíveis até o momento. Por fim, existe a possibilidade de uso dos compósitos PVC/fibras de vidro em conexões especiais, que apresentam alma metálica de reforço para suportarem elevadas pressões, e em torneiras e outros dispositivos sanitários que apresentem partes metálicas.
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Soler, David C. "The PP1 gamma isoforms restore spermatogenesis but not fertility in PP1 gamma null mice." [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1259087463.
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Thesis (Ph.D.)--Kent State University, 2009.Title from PDF t.p. (viewed May 17, 2010). Advisor: Srinivasan Vijayaraghavan. Keywords: sperm; spermatogenesis; PP1gamma2; PP1gamma1; mice; transgene. Includes bibliographical references (p. 102-123).
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Kazakauskaitė, Ieva. "Teisė į PVM atskaitą kaip fundamentalus PVM principas: praktinės šios teisės realizavimo problemos Lietuvoje." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2008~D_20101125_183238-74870.
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Pridėtinės vertės mokestis (toliau PVM) – mokestis imamas nuo papildomai sukurtos pridėtinės vertės, juo apmokestinant prekių tiekimą ir paslaugų teikimą. Pirmą kartą PVM įvestas Prancūzijoje 1957 m., tačiau galutinis šio mokesčio teisinis sureguliavimas siejamas su 1977 m. gegužės 17 d. priimta Šeštąja Tarybos direktyva. Lietuvoje nagrinėjamą mokestį reglamentuoja Lietuvos Respublikos pridėtinės vertės mokesčio įstatymas, kuris yra visiškai suderintas su Europos Sąjungos teisės aktais PVM srityje. PVM yra bendro pobūdžio, vartojimo, netiesioginis, daugiapakopis mokestis, renkamas atsižvelgiant į sukurtą pridėtinę vertę. Į valstybės biudžetą PVM turi pervesti mokesčio mokėtojai – prekybos ir tiekimų grandinės dalyviai, tačiau faktiškai šį mokestį sumoka galutinis vartotojas, įsigydamas prekę ar paslaugą. Teisė į PVM atskaitą yra fundamentalus PVM principas, kuriuo grindžiamas visas PVM veikimo mechanizmas. PVM, sumokėtas visuose civilinės apyvartos etapuose, iki galutinio prekės ar paslaugos pardavimo turi būti atskaitomas. Apmokestinant prekių ar paslaugų teikimą kiekvienoje civilinės apyvartos stadijoje ir uždraudus atskaitą, sukurta pridėtinė vertė būtų apmokestinama ne vieną, o gal ir daugiau kartų. Teisės į PVM atskaitą insituto pagalba mokestinė našta iš ekonominę veiklą vykdančių asmenų sektoriaus yra perkeliama į vartojimo sektorių, taip įgyvendinant fiskalinio neutralumo principą ir užtikrinant gamybos ir tiekimų grandinėje dalyvaujančių subjektų lygybę ir sąžiningą... [toliau žr. visą tekstą]Value-Added Tax (VAT) is a tax on the supply of goods and services. VAT was introduced in France on 1957. When the Sixth VAT Directive was adopted in 1977, the final adjustment and harmonization of VAT was reached. In the Republic of Lithuania there is a Value-Added Tax law, which is harmonized with the European Union acts. VAT is an indirect, common, multi-stage, consumption tax. The taxable person have to pay VAT in the national budget for the value, which was created in the production and distribution process. VAT is levied upon the articles of trade before they reach the customer, who eventually pays the tax-inclusive market price. Actually the VAT is pied by the final customer. The right to deduct VAT is the fundamental principle of VAT. All VAT working mechanism is based on this right to deduct. VAT, pied at all stages of production and distribution, have to be deducted by the business participants of the supply-chain. This institute – right to deduct VAT – helps to reach the situation that the payer of the VAT does not suffer a tax, because the final consumer, who is unable to deduct this tax, bears the total VAT. Consequently the fiscal neutrality and fair competition of business participants in the supply-chain is assured. The taxable person, who wants to implement his right to deduct VAT, has to meet the requirements: to do real acts of purchase and sale, formalize it in the invoice or any other accounting document, to be honest and not to abuse the tax laws. The... [to full text]
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Bonacin, Renata Fogaça. "Hidrogéis de PVP e blendas de PVP/polianidridos como potenciais curativos para feridas crônicas." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-05122011-140143/.
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Hidrogéis compreendem uma importante classe de materiais poliméricos adequados à aplicação como curativos de feridas e queimaduras. A estrutura tridimensional hidrofílica dos hidrogéis permite que estes mantenham a umidade ideal no leito das feridas, absorvam o exsudato e não causem danos ao novo tecido durante as trocas dos curativos. No caso dos hidrogéis, essas trocas podem ser menos frequentes. Além disso, curativos que auxiliem na remoção de tecidos necrosados e ainda sejam capazes de oferecer tratamentos extras que acelerem o processo de cicatrização são desejáveis. Este trabalho apresenta a produção de materiais à base de hidrogel capazes de auxiliar neste processo de diferentes maneiras. Primeiramente, são apresentados hidrogéis formados a partir de nanofibras de poli(N-vinil-2-pirrolidona) (PVP) produzidas por eletrofiação, seguido da reticulação através da utilização de radiação UV-C ou reação de Fenton. A utilização da eletrofiação como técnica auxiliar na formação dos hidrogéis permitiu o controle da porosidade através da formação de fibras de diferentes diâmetros. A evidência de tal propriedade foi constatada através da produção de materiais que apresentam diferentes perfis de liberação da proteína modelo albumina de soro bovino (BSA). O hidrogel de PVP nanoestruturado foi capaz de liberar e manter a atividade da colagenase, uma importante enzima aplicada no tratamento de feridas via desbridamento enzimático, durante as 48 horas em que foi avaliado. Além disso, hidrogéis bactericidas nanoestruturados foram produzidos a partir de nanocompósitos de PVP e nanopartículas de prata (AgNP) produzidos por eletrofiação. Esses hidrogéis apresentaram propriedades térmicas semelhantes aos hidrogéis sem AgNP, diminuindo, contudo, a sua capacidade de intumescimento. Esses hidrogéis mostraram-se ativos contra bactérias gram-positivas e gram-negativas a partir de 100 ppm de AgNPs. Adicionalmente, foi estudada a formação de um hidrogel modelo composto PVP/AgNP/Imidazol, almejando-se a produção de um material bactericida-fungicida a base de hidrogel. Este hidrogel apresentou atividade conta três espécies de Candida a partir de 500 ppm de imidazol no material. Embora exista a formação de um complexo estável entre AgNP e Imidazol, cálculos teóricos e a constatação da atividade fungicida corroboram com o fato de que derivados imidazólicos podem ser liberados a partir deste hidrogel híbrido. A produção de hidrogéis físicos compostos por blendas de PVP/Polianidridos sintetizados a partir de derivados de hidroxicinamatos e ácido salicílico, capazes de liberar moléculas de interesse biológico quando parcialmente degradados hidroliticamente, também é descrita neste trabalho. Os resultados indicam que interações hidrofóbicas entre a PVP e os polianidridos sintetizados podem ser responsáveis pela formação dos hidrogéis físicos e pela miscibilidade das blendas produzidas. Os hidrogéis físicos de PVP/Polianidridos foram obtidos na forma de filmes por evaporação do solvente. Micro- e nanofibras também foram obtidas por eletrofiação. Desta maneira, o presente trabalho contribui com o desenvolvimento de uma geração de curativos multifuncionais aplicados no tratamento de feridas crônicas e queimaduras.Hydrogels comprise an important class of polymeric materials that finds application as wound and burn dressings. The hydrophilic three-dimensional structure of hydrogels helps to provide the ideal humidity at the wound bed, to remove exsudates and to prevent damages to the new tissue during dressing substitution. Furthermore, these wound dressings are able to remove necrotic tissues and, therefore, capable to offer extra treatments that would benefit the healing processes. This work describes the production of hydrogel based materials that are able to act in wound healing by different ways. First, it is presented hydrogels composed of poly(N-vinyl-2-pyrrolidone) (PVP) nanofibers produced by electrospinning, followed by its crosslinking using UV-C radiation or Fenton reaction. The use of electrospinning in the hydrogel formation allowed porosity control by obtaining fibers of different diameters. This was evidenced by achieving materials that present different release profiles of the model protein bovine serum albumin (BSA). The nanostructured PVP hydrogel was capable of releasing and maintaining collagenase activity during 48 hour of evaluation. This is an important enzyme that find application in wound healing based on enzymatic debridement. Moreover, nanostructured bactericidal hydrogels were produced from PVP and silver nanoparticles (AgNP) composite through electrospinning, resulting in hydrogels with thermal properties similar to those hydrogels without AgNP, decreasing its swelling ability. These hydrogels were active against gram-positives and gram-negatives bacteria starting from 100 ppm of AgNP. In addition, the production of a model hydrogel composed by PVP/AgNP/Imidazole was investigated, aiming at a bactericidal-fungicidal hydrogel based material. This hydrogel was active against three Candida having 500 ppm of imidazole into the structure. In spite of the formation of a stable complex between AgNP and imidazole, theoretic calculations and the observed fungicidal activity corroborate with the fact that imidazoles derivatives can be released from this hybrid hydrogel. Physical hydrogels composed of PVP/Polyanhydrides blends were synthesized from hydroxycinammates derivatives and salicylic acid. These materials which were capable of releasing molecules with biological potential upon hydrolysis, are also described in this work. The results indicate that hydrophobic interactions between PVP and the synthesized polyanhydrides could be responsible for the hydrogel formation and blend miscibility as well. PVP/Polyanhydride physical hydrogels were obtained from cast films. Micro- and nanofibers were also obtained by electrospinning. Thus, the present work contributes with the development of the new generation of smart dressings for wound and burn healing.
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Bernhard, Kathleen C. "Methods to create and characteristics of porous poly(vinyl) alcohol for the purpose of facial implants." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53112.
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Facial implants are becoming more common in America and across the world. In the United States last year, over 260,000 augmentation and reconstruction surgeries were performed on facial cartilage areas, while over two million soft tissue fillers were administered. The current implants on the market, though, are deficient in three major areas: they are too rigid, susceptible to migration, and require a large incision. Alternatively, dermal fillers lack shape and biodegrade too quickly. Poly(vinyl) alcohol (PVA) cryogel is a promising hydrogel alternative due to its softness, durable nature and ease of cast molding. While biocompatible, it does not elicit a fibrous response with firm adhesion and could migrate. The goal of this study is to develop a biodurable implant material that has soft-tissue elasticity, pores for adhesion, and swelling for small incisions.
In this research, multiple porosity inducing methods are applied to PVA cryogel. These include a casting PVA cryogel over a porogen then leaching it in a solvent, a gaseous exothermic reaction, creating composites with biodegradable components, as well as using molds to alter the surface texture. Once created, the samples then underwent a series of tests to determine their mechanical properties which include elasticity, tensile strength, elongation, tear strength, pore size, and porosity. Swelling ratio of nonporous PVA cryogel was also considered.
Porous PVA cryogel made with a high PVA weight percentage (30%) showed equivalent mechanical properties to that of cartilage. Porous PVA cryogel manufactured with a lower weight percent (10% and 20%) were shown to have similar elastic properties to that of adipose tissue. The surface texture methods, gas method, casting and leaching method, and composites made with CaPO4 and chitosan were all shown to create pores large enough for ingrowth. Samples created with a porosity large enough to encourage ingrowth include the gas method, casting and leaching method, and the CaPO4 composites. The swelling ratio was shown to increase as the weight percentage of PVA in the samples decreased. These quantified characteristics can be used to select the appropriate porous PVA cryogel required for a range of applications including facial implants.
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dos, Prazeres Arruda da Silva Alves Maria. "Síntese e caracterização do poli(cloreto de vinila) modificado com grupos alquila." Universidade Federal de Pernambuco, 2009. https://repositorio.ufpe.br/handle/123456789/8035.
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Previous issue date: 2009Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco
O PVC é um polímero com ampla aplicação principalmente devido à sua compatibilidade com uma grande variedade de aditivos. A plasticidade do PVC necessária para sua aplicação em embalagens de acondicionamento de alimentos, sangue e hemoderivados é obtida com a utilização de um alto percentual de aditivos. Estes aditivos tendem a migrar para o conteúdo das embalagens provocando uma contaminação indesejável. A plastificação interna do PVC é uma estratégia para evitar este problema. Neste trabalho relatamos a síntese e caracterização estrutural de derivados de PVC modificados a partir de reações de substituição nucleofílica com os reagentes organomagnesianos brometo de propilmegnésio, brometo de hexilmagnésio e brometo de hexadecilmagnésio. Foi feito o estudo da reatividade do PVC em relação aos reagentes organomagnesianos variando-se as condições do meio reacional. Os polímeros sintetizados foram caracterizados por espectroscopia de absorção na região do infravermelho e por espectroscopia de ressonância nuclear magnética de hidrogênio e carbono, esta última em solução e no estado sólido. Variações da temperatura durante a reação de substituição levam à degradação dos polímeros e as reações processadas em temperatura ambiente favorecem a reticulação de cadeia, enquanto que as ocorridas sob refluxo contínuo levam a percentuais de substituição de até 8% sem que se observe degradação por reações de eliminação ou reticulação
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Santa, Cruz Pacheco Carolina Maritza. "Efecto de tres suplementos macromoléculas (pva, pvp y bsa) sobre la tasa de maduración, division y desarrollo embrionario in vitro de ovocitos bovinos procedentes de ovarios obtenidos de camal." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2012. https://hdl.handle.net/20.500.12672/1546.
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El presente estudio se realizó para evaluar el efecto de cuatro suplementos de macromoléculas sobre la tasa de maduración nuclear, así como también determinar la tasa división de ovocitos y desarrollo embrionario posterior a la fecundación a las 48 horas y 168 horas (7 días), respectivamente. Los ovarios fueron obtenidos de animales sacrificados, transportándose al laboratorio en un termo conteniendo solución salina al 0.09%, suplementada con antibiótico-antimicótico a 37 °C. Los CCO´s se obtuvieron de la aspiración de folículos de entre 2-6mm; luego de ser observados en un estéreomicroscopio, 692 ovocitos con dos o más capas de células fueron calificados como aptos para ser madurados en medio TCM-99 enriquecido con suplemento de macromolécula: PVP o PVA o BSA o SFB según sea el tratamiento; cultivados a 39°C bajo una atmósfera de 5% de CO2. Cumplido el tiempo de maduración (24 horas), los ovocitos fueron removidos del medio y lavados con PBS suplementado con SFB y 1 mg/ml de hialuronidasa, para ser fijados en una solución de etanol: ácido acético (3:1). Para la evaluación de la maduración nuclear, se colocaron los ovocitos en una lámina portaobjeto y teñidos con 1% de orceína; las mismas fueron observadas bajo un microscopio para ser evaluadas y clasificadas como Vesícula Germinal (VG), Metafase I (MI), Anafase-Telofase, Metafase II (MII) y degenerados. Para la fecundación se usaron 1680 ovocitos, madurados bajo las mismas condiciones y fecundados con espermatozoides obtenidos de pajillas. Para la obtención de los espermatozoides motiles se centrifugo a 300 gravedades durante 10 minutos bajo una gradiente de Percoll (45/90); el sobrenadante fue retirado y el pellet obtenido retirado para ser reconstituido con TL-STOCK. Los ovocitos maduros y espermatozoides fueron co-cultivados durante 18 horas a 39°C con 5% de CO2 en medio de cultivo KSOM-AA; luego de 48 horas las células cocultivadas fueron trasladadas al medio de cultivo SOF. En el experimento 1, en los ovocitos que alcanzaron la maduración nuclear (Metafase II) se encontró diferencia significativa solo entre los suplementos de macromolécula PVA y SFB con 19.3 + 1.8 y 16.3 + 0.8, respectivamente; mientras que en los grupos PVP, PVA, BSA y PVP, BSA, SFB, respectivamente no se encontró diferencia estadística significativa. En el experimento 2, la tasa de división y desarrollo embrionario posterior a la fecundación a las 48 horas y 168 horas, respectivamente no se encontró diferencia estadística significativa. Estos resultados indican que los suplementos de macromoléculas proporcionan condiciones y requerimientos importantes para la progresión desde estadios de metafase I a metafase II.
Palabras claves: Maduración In vitro, ovocitos bovinos, fecundación In vitro.--- The present study was made to evaluate the effect of four macromolecule supplements on the rate of nuclear maturation, as well as to determine the rate division of oocytes and embryonic development subsequent to the fertilization to the 48 hours and 168 hours (7 days), respectively. The ovaries were obtained from sacrificed animals, being transported to the laboratory in a thermos flask containing saline solution to the 0,09%, with antibioticantimycotic at 37 °C. The CCO´s was obtained from the aspiration of follicles of between 2-6mm; after being observed in stereomicroscope, 692 oocytes with two or more layers of cells were described like apt being in the middle matured TCM-99 enriched with macro-molecule supplement: PVP or PVA or BSA or SFB according to are the treatment; cultivated at 39°C under an atmosphere of 5% of CO2. Turned the time of maturation (24 hours), the oocytes were removed of means and washings with PBS supplemented with SFB and 1 mg/ml of hyaluronidase, to be fixed to an ethanol solution: acetic acid (3: 1). For the evaluation of the nuclear maturation, the oocytes on the slide and dyeings with 1% of orceína were placed; the same ones were observed under a microscope to be evaluated and to be classified like germinal vesicle (VG), metaphase I (MI), anaphase-telophase, metaphase II (MII) and degenerated. For the fertilization 1680 oocytes, matured under the same conditions and fertilized were used with obtained spermatozoa of tubules contained it.. For the obtaining of the motile spermatozoa by centrifuge myself to 300 gravities during 10 minutes under a gradient of Percoll (45/90); the supernatant was retired and pellet obtained retired to be reconstituted with TL-STOCK. The mature oocytes and spermatozoa Co-were cultivated during 18 hours to 39°C with 5% of CO2 in the middle of culture KSOM-AA; after 48 hours the Co-cultivated cells were transferred to means of culture SOF. In experiment 1, in the oocytes that reached the nuclear maturation (Metaphase II) was single significant difference between the macromolecule supplements PVA and SFB with 19.3 + 1.8 and 16.3 + 0.8, respectively; whereas in groups PVP, PVA, BSA and PVP, BSA, SFB, respectively was not significant statistical difference. In experiment 2, the rate of division and embryonic development subsequent to the fertilization to the 48 hours and 168 hours, respectively was not significant statistical difference. These results indicate that the macromolecule supplements they provide conditions and important requirements for the progression from stages of metaphase I to metaphase II. Key words: In vitro Maturation, oocytes bovine, In vitro fertilization.
Tesis
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Cook, Joseph P. "PVP Microgels : Theory and Applications." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520970.
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Augustsson, Johanna, and Ulrika Henningsson. "Migration of plasticisers from PVC." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20877.
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A common problem whit Polyvinyl chloride (PVC) is that plasticisers tend to migrate during use. When the plasticisers migrate the material gets stiffer, this can for example cause cracks in the PVC material. Some PVC tends to crack more easily than other; finding out what is causing this problem would bring answers to a number of questions.We have done a study in cooperation with VCC. Former studies, by VCC, with variable results have been executed trying to solve the problem with cracks. We wanted to design a new test method to see if we were able to provoke cracks. If we were able to provoke these cracks, we could see when and why cracks appear in the current PVC item.During our work, we evaluated two different PVC coated materials; PVC1 and PVC2. Both materials had two different structures - with foam backing and without foam backing. We performed mechanical, thermal and chemical treatments on the materials and with help from those experiment we were able to provoke cracks in one of our PVC coated materials.According to our results, PVC1 shows a higher tendency to crack in comparison with PVC2, which only developed wrinkles. In PVC1 we could see cracks in an early stage during our mechanical testing. We evaluated our result by using a microscope and we observed a pattern in the tendency to develop cracks. PVC1 with foam backing had a higher tendency to crack in comparison with PVC1 without foam. Materials that have been abraded before flexing also tend to crack more easily.In order to see if the plasticisers migrated into the foam during our experimental work we performed an extraction of PVC1, according to the results the plasticisers might have migrated to the foam.The major conclusion from this study of PVC1 and PVC2 is that PVC1 tends to crack more easily than PVC2. The foam seems to have a negative effect on the PVC. The abrasion before ageing also have a negative effect on the PVC coated material. We could not see that the chemicals affected the materials.One of the main purposes with this study was to find a new test method for PVC coated items. We think that our test method with the ageing of the material in combination with the mechanical tests as Martindale and Ballyflex is a suitable test method while testing PVC coated materials.Program: Textilingenjörsutbildningen
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Matuška, Martin. "Aplikace PVD povlaků pro frézování." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229048.
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This dissertation treats of the influence of PVD coats to a change of tool lifetime. The theoretical part of the dissertation describes the adjustment of tools before the process of coating. Following part describes the specific properties of deposited layers of the coating and its measuring. There is also the enumeration and specification of selected ways of depositing PVD coats and brief description of its advantages and disadvantages. Second part of the dissertation is focused on an experiment with measuring of the tool force loading and its change depending to the tool wear. There are compared four short four-edged milling cutters with a coat and as well without it. Those tools were made of high speed steel by the conventional way and also by the powder metallurgy. Milling operation was done by down and up milling technique. The evaluation of the experimental results for powder metallurgy tools confirmed that these tools are advantageous compared to the standard high speed steel tools.
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Araújo, Rogério Gomes. "Compósitos PVC / nanotubos de carbono." reponame:Repositório Institucional da UFSC, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/93788.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Florianópolis, 2010Made available in DSpace on 2012-10-25T03:25:18Z (GMT). No. of bitstreams: 1 287051.pdf: 5314527 bytes, checksum: ffb9e68f043a08966600d7b0d04b1d08 (MD5)
Nanocompósitos poliméricos com nanotubos de carbono tem despertado grande interesse da comunidade científica devido às propriedades elétricas, térmicas e mecânicas destas partículas, que foram recentemente descobertas. A área superficial e relação entre o comprimento e do diâmetro extremamente elevadas dos nanotubos de carbono oferecem a possibilidade de mudanças significativas nas propriedades dos polímeros com a adição de pequenos teores de nanotubos. A dispersão adequada dos nanotubos de carbono na matriz polimérica é um dos principais desafios no desenvolvimento de nanocompósitos poliméricos. Neste trabalho foram obtidos nanocompósitos de nanotubos de carbono em matriz de poli(cloreto de vinila) [PVC] pelo processo de mistura com o polímero em solução de tetraidrofurano com posterior evaporação do solvente. Nanocompósitos com teores entre 0,1 e 1,0 %m de nanotubos de carbono de parede múltipla, não funcionalizados e funcionalizados com grupos carboxila, foram estudados. Nanotubos de carbono foram sintetizados pelo processo de deposição catalítica de vapor (CVD), entretanto devido ao baixo rendimento do processo e a necessidade de um maior volume de material foram utilizados nanotubos comerciais. A dispersão dos nanotubos na matriz de PVC foi analisada por microscopia eletrônica de transmissão (TEM) e ressonância magnéticos nuclear de baixo campo (RMN), indicando que os nanotubos se encontram dispersos na matriz com alguns domínios de aglomeração, independente do teor ou da funcionalização dos nanotubos. As propriedades mecânicas, módulo de elasticidade e resistência à tração máxima dos nanocompósitos permaneceram inalteradas em relação ao PVC puro. Entretanto, a deformação na ruptura foi significativamente reduzida nos nanocompósitos, independente do teor de nanotubos adicionados, sugerindo que os domínios de nanotubos aglomerados influenciam esta propriedade. A temperatura de transição vítrea do PVC nos nanocompósitos independe do teor de nanotubos de carbono, enquanto que a resistividade elétrica volumétrica foi reduzida em até dez ordens de grandeza nos nanocompósitos com teor superior a 0,4 %m de nanotubos de carbono em relação ao polímero puro. Este resultado habilita o uso dos nanocompósitos estudados em aplicações como material semicondutor.
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Caldart, Leandro. "Gestão de resíduos de PVC." Florianópolis, SC, 2005. http://repositorio.ufsc.br/handle/123456789/103053.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Ambiental.Made available in DSpace on 2013-07-16T02:47:20Z (GMT). No. of bitstreams: 0
O ciclo de vida útil dos produtos elaborados com resina de PVC é bem maior do que o de outras resinas e cerca de 88% deles podem durar de 2 a 100 anos. Mesmo com um duradouro ciclo de vida, o PVC não permite justificativa consciente para se ignorar os riscos que eventualmente possa causar à natureza e à sociedade, como qualquer outro produto desenvolvido pelo engenho humano. Esta pesquisa discute a problemática da geração de resíduos plásticos e as possibilidades práticas de gestão de resíduos de PVC nos cenários brasileiro e europeu. O objetivo principal deste estudo foi o de analisar se o Brasil possui diretrizes adequadas para uma boa gestão dos resíduos de PVC. Pode-se concluir que para uma boa gestão dos resíduos sólidos no Brasil, e conseqüentemente de resíduos de PVC, necessitamos uma de legislação que contemplem o setor de reciclagem, patrocinados pelo Congresso Nacional, que definam políticas, ou seja, um conjunto de objetivos, princípios, diretrizes, para atividades específicas como a reciclagem. Os três principais fundamentos para que ocorra a reciclagem são a coleta, a educação e o mercado, fazendo parte do processo os governos, as empresas, os cidadãos, os catadores e os recicladores. Somente com a participação e envolvimento de todos esses atores a gestão de resíduos será eficaz, tornando-se imprescindível a existência de uma Política Nacional de Resíduos Sólidos.
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Skoupý, Jiří. "Pohon regulačního kruhu PVE Merkersbach." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228065.
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This thesis is focused on determination of forces acting to regulation ring of water power plant Markersbach (Germany). Solution of the problem is realized for two variants of servomotors – with and without servomotors acting surfaces balancing. Next topics of this thesis are strenght calculation of piston rod and bottom of the servomotors. Minimalization of the size of servomotors plungers by change of regulation kinematics has been done and minimal pressure in the pressure tank is determined. At the conclusion of this thesis received results are mentioned and its interpretation has been done. This thesis is provided for company Litostroj Power, ČKD Blansko Engineering, a.s.
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Rosecký, Pavel. "Analýza životnosti střešních PVC fólií." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392321.
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Roofing foils are known for several years as building material for roof hydro insulation but their life service is not yet fully known. This thesis is focused on problematics of life service of roofing foils. In theoretical part there is discribed structure of foils and impacts which assist degradation processes. Practical part modifies the methodology artificial aging which is simulated in QUV tester and Q-SUN XE3 tester lumber-rooms. The thesis is trying reach with the results to natural aging as close as possible. The testing captures attributes which are more prone to degradation.
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Hanco, Conto Edgar Gustavo. "Estudio de propiedades físicas de películas semirrígidas transparentes de policloruro de vinilo (PVC) fabricadas por extrusión a partir de PVC virgen y PVC recuperado." Bachelor's thesis, Pontificia Universidad Católica del Perú, 2018. http://tesis.pucp.edu.pe/repositorio/handle/123456789/12878.
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En las sociedades modernas, los plásticos son usados cada vez en un mayor número
de aplicaciones, por lo que las industrias procesan más cantidad de materia prima y,
como consecuencia, se generan más mermas y residuos. Esta situación llega a ser
problemática cuando esas mermas y residuos se desechan sin antes recuperarlas o
reciclarlas. Como respuesta al problema planteado, la PUCP desarrolló un proyecto de
investigación, que propuso recuperar las mermas de películas semirrígidas
transparentes de policloruro de vinilo (PVC) del proceso productivo de una empresa con
la finalidad de obtener un material que fue usado como materia prima junto con la granza
(pellets) de PVC virgen para la fabricación de nuevas películas.
El objetivo de la presente tesis es estudiar propiedades físicas de las películas de PVC
semirrígidas transparentes fabricadas por extrusión de PVC virgen y PVC recuperado
para luego compararlas con las propiedades de las películas de PVC fabricadas solo
con material virgen con el fin de validar su uso en la fabricación de artículos de uso
escolar como forros de cuadernos, micas y cubiertas de fólderes.
En primera instancia se procedió a caracterizar, según las normas ASTM, muestras de
películas semirrígidas transparentes que son fabricadas con PVC virgen. Luego, se
realizaron ensayos para determinar, primero, el mejor tipo de merma; luego, la mejor
composición de aditivos y posteriormente, la mejor composición de merma a usar en el
proceso de recuperación. Finalmente se procedió a caracterizar, considerando los
resultados obtenidos previamente, las muestras fabricadas a partir de PVC virgen y PVC
recuperado, este último obtenido en un sistema de recuperación diseñado
especialmente para tal fin.
Mediante los análisis efectuados se identificó que las películas obtenidas con mayor
proporción de PVC recuperado disminuyen ligeramente su transparencia y propiedades
mecánicas, además su estabilidad térmica, representada por su temperatura de
degradación, tampoco varía mucho, por lo que se demuestra que es posible incorporar
hasta 20% de material recuperado en el proceso de producción de películas de PVC
que serán usadas en la fabricación de artículos escolares.Tesis
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Laucius, Gediminas. "Teisės į PVM ataskaitą ir prievolės registruotis PVM mokėtoju santykis pridėtinės vertės mokesčio raidos kontekste." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2009~D_20100224_104841-25561.
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Pridėtinės vertės mokestį yra įsivedusios apie 150 pasaulio valstybių, jis sudaro reikšmingą valstybių biudžeto pajamų dalį (statistiškai apie penktadalį). Pagrindinėmis priežastimis, nulėmusiomis beprecedentį PVM populiarumą ir sparčią mokesčio integraciją į daugumos pasaulio valstybių mokestines sistemas, laikomi reikšmingi alternatyvių netiesioginių apyvartos mokesčių sisteminiai trūkumai, kurių PVM neturi. Pridėtinės vertės mokesčio unikalumas ir pranašumas prieš kitus apyvartos mokesčius slypi pirkimo PVM atskaitos mechanizme, sudarančiame sąlygas apmokestinti tik kiekvienoje iš prekių ir paslaugų paskirstymo grandžių sukurtą pridėtinę vertę. Todėl, siekiant, kad PVM funkcionuotų efektyviai ir sugebėtų išlikti neutraliu apyvartos mokesčiu, yra labai svarbu, kad pirkimo PVM atskaita apmokestinamiesiems asmenims būtų arba visai neribojama, arba ribojama tik išimtiniais atvejais ir tik proporcingai tokiu ribojimu siekiamiems tikslams.
Dėl šios priežasties magistro baigiamajame darbe nagrinėjama problema, ar pagrįstai Lietuvos PVM įstatymo nuostatos, suteikiančios teisę į PVM atskaitą tik PVM mokėtojams, riboja apmokestinamųjų asmenų teisę į pirkimo PVM, patirto ir sunaudoto apmokestinamoje veikloje iki registracijos PVM mokėtoju, atskaitą.
Kaip pradinė išeities pozicija iškeliama hipotezė, kad galbūt Lietuvos Respublikos PVM įstatymo nuostatos, ribojančios apmokestinamojo asmens teisę į iki įsiregistravimo PVM mokėtoju patirtą pirkimo PVM, netinkamai įgyvendina 2006/112/EB... [toliau žr. visą tekstą]Approximately 150 countries of the world have already introduced the value added tax in their tax systems. Value added tax compose a significant portion of the income of the revenue of these states’ (statistically one fifth). As the main reasons which determined the unprecedented popularity of VAT and its rapid integration into the tax systems of the most countries of the world are recognized the meaningful disadvantages of the alternative turnover tax systems, which are not typical to the systems of VAT. The uniqueness of value added tax and its advantage over the other turnover taxes lies in the mechanism of input VAT deduction. Certain mechanism allows to charge only the value added created in the stages of distribution (no cascade effect emerges). Therefore in order for VAT to operate effectively and to remain neutral, it is particularly important that taxable persons’ right to input VAT deduction is either not restricted at all, or if restricted then only in exceptional cases and only in the strict proportionality with the objectives in purpose. For the above reasons we examine the problem whether the provisions of the Lithuanian Law on VAT which entitle solely the VAT payers with the right to VAT deduction legitimately restrict the taxable persons’ right to deduct input VAT incurred and absorbed in the taxable activity prior the registration as VAT payer. As the initial starting position we hypothesize that conceivably the provisions of the Lithuanian Law on VAT... [to full text]
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ALCANTARA, MARA T. S. "Hidrógeis poliméricos com nanopartículas de prata para aplicações médicas." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23511.
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Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-03-03T10:48:26Z
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Pedroso, Maitê Golinelli Vanella. "Estudo comparativo de colágeno hidrolisado e comercial com adição de PVA." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-11032010-111128/.
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O desenvolvimento de novos materiais tem sido baseado na mistura de dois ou mais polímeros ou biopolímeros, onde soluções destes são misturadas em diferentes proporções na tentativa de se obter materiais com propriedades distintas das de seus precursores. Neste trabalho foram analisadas blendas colágeno:PVA. O colágeno utilizado foi o tipo I, porem proveniente de duas formas diferentes, o colágeno comercial que foi cedido pela Novaprom Food Ingredients Ltda e o colágeno obtido a partir de tendão bovino por meio de hidrólise alcalina em diferentes tempos (24h e 96h). As blendas e os colágenos foram caracterizados por análise térmica (DTG e DSC), microscopia eletrônica de varredura (MEV), espectroscopia de absorção no infravermelho (FT-IR) e analises reológicas. As curvas DSC mostraram que o colágeno comercial é o de maior temperatura de desnaturação e que a adição de PVA não altera essa temperatura. Já as curvas TG mostraram que o PVA, seja qual for sua massa molecular, aumenta a estabilidade térmica do colágeno. A microscopia eletrônica mostrou que os colágenos com tratamento alcalino apresentam uma estrutura fibrilar e pouco desorganizada, enquanto o colágeno comercial apresenta uma estrutura uma pouco mais compacta. Através do FT-IR foi possível observar que a presença de PVA nas blendas não influencia na presença dos picos, sugerindo que não há interação química entre os mesmos. A análise reológica permitiu comparar os módulos elástico (G\') e viscoso (G\") dos géis em diferentes proporções, tendo todos eles valores de G\' maior do que G\", ou seja, podemos concluir que os materiais são mais elásticos do que viscosos. Observa-se também a influência na viscosidade dos géis com a adição de PVA ao mesmo, sendo a viscosidade maior com o aumento da massa de PVA adicionado.The development of new materials has been based on the mix of two or more polymers or biopolymers where solutions are mixed in different portions trying to get materials with distinct properties from their precursors. In this work different collagen solutions and collagen-PVA blends were analyzed. The used collagen was the type I, however obtained from two different forms, the commercial collagen that was provided by Novaprom Food Ingredients Ltda and the collagen obtained from bovine tendon by alkaline hydrolysis in different times (24h and 96h). The blends and collagen were characterized by thermal analysis (DTG and DSC), electronic scan microscopy (ESM), infrared absorption spectroscopy (FT-IR) and rheological analysis. DSC curves showed that the commercial collagen has the highest denaturing temperature and that the addition of PVA does not change this temperature. In other hand, TG curves showed that PVA, in any given molecular weight, increases collagen thermal stability. Electronic microscopy shows that collagen with alkali treatment have a fibrillar and little disorganized structure, insofar, the commercial collagen have a little more compact structure. By FT-IR it was to possible observe that the presence of PVA on blends have no influence on the peaks, suggesting that there is no chemical interaction between then. Rheological analysis allow to compare the elastic module (G\') and the viscous module (G\'\') from blends in different proportions. All the obtained values for G\' are higher than G\'\', so it can be conclude that samples are more elastic than viscous.
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Momesso, Roberta Grazzielli Ramos Alves Passarelli. "Incorporação e liberação de resveratrol em hidrogéis poliméricos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-29082011-143430/.
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Resveratrol (3, 4, 5-trihidroxiestilbeno) é um polifenol produzido por uma grande variedade de plantas em resposta ao estresse e encontrado predominantemente em cascas de uvas. Este princípio ativo apresenta vários benefícios à saúde, como a capacidade antioxidante, relacionada à prevenção de diversos tipos de câncer e do envelhecimento precoce da pele. No entanto, apresenta baixa biodisponibilidade quando administrado por via oral, o que torna interessante sua aplicação tópica. O principal objetivo deste trabalho foi a incorporação de resveratrol em hidrogéis poliméricos para obtenção de um sistema de liberação utilizado topicamente contra o desenvolvimento de desordens cutâneas, como o envelhecimento cutâneo e o câncer de pele. As matrizes poliméricas compostas por poli(N-vinil-2-pirrolidona) (PVP), poli(etileno glicol) (PEG) e ágar ou PVP e propano-1,2,3-triol (glicerina) e irradiadas a 20 kGy foram caracterizadas pelos ensaios de fração gel e intumescimento; sua biocompatibilidade preliminar foi avaliada in vitro por meio do ensaio de citotoxicidade utilizando o método de incorporação do vermelho neutro. Devido à baixa solubilidade do resveratrol em água, verificou-se o efeito da adição de 2% de etanol às matrizes. Todas as matrizes estudadas, contendo ou não álcool, apresentaram alto grau de reticulação, capacidade de intumescimento e não apresentaram toxicidade em ensaio preliminar de biocompatibilidade. Os dispositivos foram obtidos pela incorporação de resveratrol nas matrizes poliméricas, realizada de forma direta e indireta, ou seja, antes e após irradiação, respectivamente. Os dispositivos obtidos pelo método direto foram submetidos aos ensaios de fração gel, intumescimento e citotoxicidade e apresentaram-se semelhantes às respectivas matrizes. Os dispositivos contendo 0,05% de resveratrol obtidos pelo método direto e os dispositivos contendo 0,1% de resveratrol obtidos pelo método indireto foram submetidos ao ensaio de cinética de liberação durante 24 h. A quantificação do resveratrol liberado foi realizada por cromatografia líquida de alta eficiência (HPLC). Apenas os dispositivos obtidos pelo método indireto apresentaram capacidade de liberar o resveratrol incorporado, que apresentou capacidade antioxidante após liberação.Resveratrol (3, 4, 5-trihydroxystilbene) is a polyphenolic produced by a wide variety of plants in response to injury and found predominantly in grape skins. This active ingredient has been shown to possess benefits for the health, such as the antioxidant capacity which is related to the prevention of several types of cancer and skin aging. However, the oral bioavailability of resveratrol is poor and makes its topical application interesting. The purpose of this study was to immobilize resveratrol in polymeric hydrogels to obtain a release device for topical use. The polymeric matrices composed of poli(N-vinyl-2-pyrrolidone) (PVP), poly(ethyleneglycol) (PEG) and agar or PVP and glycerol irradiated at 20 kGy dose were physical-chemically characterized by gel fraction and swelling tests and its preliminary biocompatibility by in vitro test of cytotoxicity using the technique of neutral red uptake. Due to low solubility of resveratrol in water, the addition of 2% ethanol to the matrices was verified. All matrices showed a high crosslinking degree, capacity of swelling and the preliminary cytotoxicity test showed nontoxicity effect. The devices were obtained by resveratrol immobilizaton in polymeric matrices, carried out in a one-or-two-steps process, that is, before or after irradiation, respectively. The one step resveratrol devices were characterized by gel fraction, swelling tests and preliminary biocompatibility, and their properties were maintained even after the resveratrol incorporation. The devices containing 0,05% of resveratrol obtained by one-step process and 0,1% of resveratrol obtained by two-steps process were submitted to the release test during 24 h. Resveratrol quantification was done by high performance liquid chromatography (HPLC). The results obtained in the kinetics of release showed that only the devices obtained by two-step process release the resveratrol, which demonstrate antioxidant capacity after the release.
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Castro, Alex Terela Pinheiro de. "Viabilização do reaproveitamento dos \"Blister\" de PVC/AI e estudos das propriedades do PVC após processamento por radiação ionizante." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-17082009-172808/.
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O objetivo deste trabalho foi o de separar através de um processo de dissolução, o PVC e o alumínio, que são componentes das embalagens tipo blister, comumente encontradas como embalagens de remédios. Foi estudado, também o efeito da radiação ionizante sobre o PVC e por ultimo a reciclagem mecânica do PVC separado por um processo de extrusão. O material utilizado neste trabalho foi oriundo de sobras da industria farmacêutica, sendo este em forma de embalagens com defeito ou rebarbas de produção.Após a moagem do material, realizada para facilitar o manuseio e a homogeneização do sistema, foram escolhidas duas bases para realizar a dissolução do alumínio: hidróxido de sódio e hidróxido de potássio. Foi utilizado um sistema com duas concentrações (1 e 2M), as duas bases, e se o sistema teria ou não agitação. Este método limitou em oito os experimentos. Após a dissolução, amostras do material foram submetidas a radiação ionizante, realizada com doses de 50, 100, 150 e 200kGy no acelerador de elétrons modelo Dynamitron II do CTR-IPEN/CNEN-SP. Estas amostras foram submetidas a seguir, a um ensaio de resistência à tração para a analise das modificações causadas pela irradiação. A última etapa do trabalho foi a reciclagem mecânica do PVC já separado do alumínio. A reciclagem foi realizada em equipamento industrial, uma extrusora de tubos de PVC. O material foi aditivado em um misturador intensivo com lubrificantes, estabilizantes térmicos carga e pigmento, e em seguida processado na forma de eletrodutos de PVC rígido.Após os oito experimentos, o sistema com a base hidróxido de potássio concentração 2M e agitação, foi o que apresentou a melhor relação entre tempo de dissolução e característica do material resultante, não ocorrendo degradação no PVC. Nas amostras irradiadas, a coloração do material foi modificada assim como o seu alongamento que foi maior quanto maior a dose de irradiação recebidas, indicando a cisão das cadeias de PVC. A extrusão do PVC foi realizada com sucesso, conseguindo-se transformar aproximadamente 200kg de PVC, devidamente aditivado, demonstrando assim a viabilidade de todo o trabalho.The objective of this research was to separate, by means of a process of dissolution, the PVC and the aluminum that compose blister packs, generally used for pharmaceutical pills. We also studied the effect of the ionizing radiation on the PVC, and, finally, the mechanical recycling of the separated PVC, by a process of extrusion. The material we used in this work is the surplus of the pharmaceutical industry, i.e., packs with defects or burrs. We ground the material to facilitate the handling and the homogenization of the system. After that, we chose two bases for the dissolution of the aluminum: the sodium hydroxide and the potassium hydroxide. We used a system with two concentrations (1 and 2M) for each base, and for every solution we had also an agitated and a non-agitated process. From this method resulted eight experiments. After the dissolution, the samples of the material were submitted to ionizing radiation with doses of 50, 100, 150 and 200 kGy in the Dynamitron II electron accelerator of the CTR-IPEN/CNEN-SP. In the following, these samples were submitted to traction resistance tests to analyze which modifications the irradiation caused. The last step of the research was the recycling of the PVC separated from the Aliminum. We made the recycling in industrial equipment, a PVC tube extruder. The material was combined with lubricants, heat stabilizers and pigment in an intensive mixer and processed into the form of rigid PVC electrical conduits. After the eight experiments, the system with potassium hydroxide base, concentration of 2M and agitation presented the best relation between time of dissolution and characteristics of the resulting material, without degradation of the PVC. In the irradiated samples, the color of the material changed as well as its extension that was as larger as the dose of irradiation they received, indicating the dissociation of the PVC molecules. The extrusion of the PVC was successfully realized: about 200 kg (440 pounds) of properly combined were processed. This shows the viability of the whole research.
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Royaux, Adeline. "Compréhension des mécanismes de perte de plastifiant et d'exsudation des PVC plastifiés." Thesis, Cergy-Pontoise, 2017. http://www.theses.fr/2017CERG0907/document.
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Le polychlorure de vinyle (PVC) plastifié est un plastique très présent dans les collections patrimoniales et dans un état de conservation jugé souvent médiocre. Les dégradations les plus fréquentes sont l’exsudation et la perte de souplesse des objets qui sont liées à la migration progressive du plastifiant vers la surface du matériau.Les travaux de thèse visaient à mieux comprendre les processus d’altération des objets en PVC plastifiés et à préconiser des conditions de conservation et des traitements de restauration. Cette étude a été réalisée en parallèle sur des PVC de formulation simplifiée et sur des PVC anciens vieillis naturellement en musée. La cinétique de migration du plastifiant et les modifications structurales des chaînes PVC ont été caractérisées au cours d’un vieillissement artificiel des films réalisé dans les conditions les plus représentatives d’un environnement muséal d’exposition ou de conservation.L’impact du nettoyage des surfaces a été étudié en terme d’efficacité mais surtout de dégradation ultérieure du PVC et notamment de réapparition des exsudats. L’effet de différents conditionnements sur le vieillissement des PVC souples, nettoyés ou non, a également été évalué. Des matériaux d’emballage régulièrement utilisés par les restaurateurs ont été considérés.Ces travaux ont permis d’apporter un éclairage sur l’effet des méthodes utilisées lors de la restauration et la conservation des œuvres en PVC plastifiéPlasticized polyvinyl chloride (PVC) is a plastic widely used in patrimonial collections but its state of preservation is often considered as poor. The most frequent degradations are the exudation and the loss of flexibility of objects which are related to the progressive migration of the plasticizer towards the surface of the material.The project thesis aimed to better understand the alteration of plasticized PVC objects and predict conditions of conservation and restoration treatments.This study was conducted with both a simplified formulation of PVC and an ancient PVC naturally aged in museum.The kinetics of plasticizer migration and structural modifications of PVC chains were characterized during artificial ageing of films conducted through the most representative conditions of a museum environment of exposure or conservation.The impact of surface cleaning was studied in terms of efficiency but also subsequent degradation of the PVC, in particular the recurrence of exudates. The effect of different conditionings on the ageing of flexible PVC, either cleaned or not, was also estimated. Packaging materials frequently used by conservators have been considered.This work allowed achieving new insights on the effect of methods used for conservation and preservation of plasticized PVC artefacts
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TAWHEED, ANWAAR. "Papillomavirus humains (pvh) et carcinogenese genitale : caracterisation d'un nouveau pvh oncogene et mise en evidence et analyse d'un locus d'integration des pvh dans le chromosome 12." Paris 7, 1994. http://www.theses.fr/1994PA077306.
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Deux aspects de l'histoire naturelle du cancer du col uterin ont ete abordes: le role etiologique des papillomavirus humains (pvh) et le role de l'integration des pvh au genome cellulaire, en tant qu'evenement mutagene, dans la progression tumorale. Nous avons d'abord caracterise un nouveau type de pvh, le pvh66, a partir d'un cancer. Les genes e6 et e7 du pvh66 possedent l'information qui distingue les pvh oncogenes des pvh associes a un faible risque de cancer. Le pvh66 est apparente au pvh56, un type oncogene. Le pvh66 a ete detecte dans une lesion precancereuse en continuite avec le cancer dont il a ete clone et dans quelques cas de precancers genitaux. Ces faits sont en faveur d'un role du pvh66 dans la carcinogenese genitale. Nous avons ensuite mis en evidence un locus d'integration des pvh dans la region q14-q15 du chromosome 12 dans les cellules sk-v, issues d'un precancer associe au pvh16, et dans les cellules sw756, issues d'un cancer associe au pvh18. Nous avons montre que les sequences cellulaires bh5 et 7. 16. 1, adjacentes en 3' aux sequences virales dans les cellules sk-v et sw756, sont comprises dans un fragment d'adn genomique humain de 0,5 mb, delimite par deux flots cpg, que les sequences cellulaires sont distantes de 25 kb, et que la sequence bh5 est situee a 60 kb en aval d'un site not 1. Deux phases ouvertes de lecture (pol) putatives ont ete identifiees en aval des sites d'integration. La premiere renferme le site not 1, possede des caracteres d'un ilot cpg et est transcrite dans le muscle strie. Le deuxieme code pour une proteine possedant 7 sequences riches en proline, apparentees aux motifs de fixation sur des domaines sh3, impliques dans des interactions proteine/proteine permettant la transduction du signal mitogene. Les deux pol n'ont pas d'homologie avec des sequences connues. Ces resultats rendent tres plausible l'existence d'un gene cible inconnu au voisinage du locus d'integration des pvh dans la region q14-q15 du chromosome 12
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Atlan, Michaël. "Implantation et évaluation de micro-implants vasculaires (< 2mm), à base d’alcool polyvinylique." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCD035/document.
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Sur la base de précédents travaux de l’unité INSERM 1148, sur des films à base d’alcool polyvinylique, nous avons implanté et évalué des prothèses de moins de 2mm de diamètre. L’ajout de gelatine in vitro a montré des capacités d’adhérence cellulaires, compatibles avec une endothelialisation in situ, des implants garant, d’une perméabilité à long terme. Notre modèle était le remplacement de 1cm d’aorte sous rénale de rat. Ces implants, ont été utilisées comme modèle d’entrainement basse fidélité à la microchirurgie, avec de meilleurs résultats sur l’acquisition de la technique d’anastomose microchirurgicale, que les tubes en silicone antérieurement utilisé, lors de l’enseignement chez 71 étudiants. Un nouveau moyen d’imagerie pour l’exploration vasculaire par angiographie par résonance magnétique, en temps de vol sans injection chez l’animal, et la première application chez l’homme sont rapportés. Apres avoir présenté notre methode de fabrication par reticulation physique (Lyophilisation Congelation) et chimique (STMP) Cdu PVA, directement sous forme de tubes, nous avons confirmé l’hypothèse que les micro implants à base de PVA associé à la gélatine à hauteur de 1%, a permis d’améliorer la perméabilité par rapport au PVA seul, ou à tout autre ratio de gélatine ; et ce grâce à une endothélisation in situ constatées histologiquement. Les performances biomécaniques de l’implant ont aussi étaient évaluées. Au delà de 2 mois la perméabilité chute de 75% à 50%. Le vieillissement du matériel par son enraidissement, et le relargage de la gélatine pourrait expliquer cette diminution des performances au cours du tempsNon communiqué
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Rousseau, Youri. "Hybridation des technologies de jets de nanoparticules et de PVD pour la réalisation d’architectures nanocomposites fonctionnelles." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS347.
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Les films nanocomposites sont des revêtements composés de nanoparticules enrobées dans une matrice solide d’un matériau différent. L’intérêt de ces matériaux réside dans leur capacité à exploiter les caractéristiques inédites des nano-objets qu’ils contiennent tout en bénéficiant des propriétés de résistance mécanique et chimique de la matrice. Ces composites disposent de propriétés très prometteuses pour un grand nombre d’applications comme le photovoltaïque ou la photocatalyse. Plusieurs procédés de synthèse existants permettent de produire des matériaux nanocomposites par des méthodes physiques ou chimiques (co-pulvérisation, sol-gel,…). Cependant, aucun n’est assez flexible pour envisager la synthèse d’une large gamme de nanocomposites par le même procédé. Ceci est un frein au développement à l’échelle industrielle de ce type de matériaux. Le premier objectif de la thèse est de développer un procédé original de synthèse de films nanocomposites. Ce procédé présente un caractère universel en ce qu’il permet un choix a priori illimité dans la nature des nanoparticules et celle de la matrice. Le procédé développé combine un jet de nanoparticules sous vide formé par une lentille aérodynamique à un dispositif de pulvérisation magnétron qui permet de déposer la matrice. Le jet de nanoparticules permet de coupler toute source de nanoparticules à la pulvérisation. Les nanoparticules peuvent être soit synthétisées in situ en phase gazeuse, soit synthétisées préalablement en voie liquide. Une grande variété de nanoparticules peut donc être utilisée. La pulvérisation magnétron permet par ailleurs de disposer d’une très large gamme de matériaux pour la matrice (métaux, céramique, polymère). Dans le cadre de cette thèse, deux types de sources de nanoparticules ont été utilisés. Le premier est un réacteur de pyrolyse laser et le second un générateur d’aérosol. Le réacteur de pyrolyse laser permet une synthèse in-situ des nanoparticules en phase gazeuse alors que le générateur d’aérosol permet d’utiliser une suspension de nanoparticules préalablement synthétisées. Afin d’éprouver la robustesse du procédé de co-dépôt, deux types de matériaux nanocomposites ont été développés. Le premier matériau étudié est composé de nanoparticules d’or sphériques de 35 nm de diamètre, synthétisées préalablement par voix liquide, dans une matrice de silice. Le but ici est de bénéficier des propriétés optiques uniques des nanoparticules d’or dans un film résistant mécaniquement et chimiquement. Les caractérisations réalisées sur ces matériaux ont permis d’optimiser la concentration en nanoparticules d’or dans les films de manière à garder des propriétés mécaniques et chimiques compatibles avec les applications tout en gardant des propriétés optiques satisfaisantes. Le second type de matériaux étudiés est composé de nanoparticules semi-conductrices synthétisées in situ par pyrolyse laser et d’une matrice métallique. La synthèse de ce matériau permet de démontrer la flexibilité du procédé de co-dépôt à synthétiser une large gamme de films nanocomposites. Enfin, la robustesse du procédé ayant été démontrée, la conception d’un pilote industriel a été entreprise. Le but final étant de disposer d’une machine répondant aux exigences industrielles dans l’optique d’un transfert technologiqueThe nanocomposite films are coatings of nanoparticles embedded in a solid matrix of a different material. The advantage of these materials is their ability to exploit the unique properties of nano-objects while benefiting of the mechanical and chemical resistance properties of the matrix. These composites have very promising properties for many applications such as photovoltaics and photocatalysis. Several existing synthetic methods can produce nanocomposite materials by physical or chemical methods (co-sputtering, sol-gel, ...). However, none is flexible enough to consider the synthesis of a wide range of nanocomposites by the same method. This is an obstacle to the development on an industrial scale of this type of material. The first objective of the thesis is to develop an original synthesis process of nanocomposite films. This method is universal in which it presents no limit in the choice of nanoparticles and matrix. The developed method combines vacuum nanoparticle jets formed by an aerodynamic lens with a magnetron sputtering device for depositing the matrix. The nanoparticle jets can be coupled with any source of nanoparticles. Nanoparticles may be synthesized in situ in the gas phase or beforehand solution synthesis. A wide variety of nanoparticles can be used. Magnetron sputtering also enables to have a very wide range of materials for the matrix (metal, ceramic, polymer). During this thesis, two types of nanoparticles sources were used. The first one is a laser pyrolysis reactor and the second is an aerosol generator. The laser pyrolysis reactor enables in-situ gas phase synthesis of the nanoparticles while the aerosol generator use a suspension of previously synthesized nanoparticles. To test the robustness of the co-deposition process, two types of nanocomposite materials have been developed. The first material is composed of 35 nm spherical gold nanoparticles, chemically synthesized, in a silica matrix. The goal here is to benefit from the unique optical properties of gold nanoparticles in a film mechanically and chemically resistant. The characterizations carried out on these materials have optimized the gold nanoparticle concentration in the films to keep the mechanical and chemical properties compatible with applications while maintaining satisfactory optical properties. The second type of materials studied is composed of semiconductor nanoparticles in situ synthesized by laser pyrolysis and a metal matrix. The synthesis of this material demonstrates the flexibility of the co-deposition method to synthesize a wide variety of nanocomposite films. Finally, the design of an industrial pilot was undertaken. The final goal is to have a pilot-scale setup that meets industry requirements in the context of a technology transfer
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MORGAT, ANNE. "Contribution a l'etude structurale des p21 ras. Simulations par dynamique moleculaire de la p21 ha ras." Paris 11, 1991. http://www.theses.fr/1991PA112159.
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La connaissance structurale approfondie des proteines ras (p21 ras) permet une meilleur comprehension des mecanismes reactionnels regulant leur activite biologique (fixation des nucleotides gdp, gtp et hydrolyse du gtp, en presence d'un ion mg ii). L'etude des complexes p21. Gppnp et p21. Gdp dans leur environnement cristallin, associee a une etude de leur surface moleculaire a montre des sites potentiels d'interactions avec d'autres macromolecules. Les proprietes dynamiques de la p21 ras complexee a une molecule de gppnp et un ion mg ii ont ete etudiees par dynamique moleculaire (programme discover). Cette simulation a apporte une meilleure connaissance des interactions entre la proteine et son ligand. L'effet de certaines mutations a pu etre evalue. Cette etude a permis d'emettre des hypotheses sur les sites d'interactions avec la proteine gap et le facteur d'echange, ainsi que sur leurs mecanismes d'action
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Kurek, Ana Paula. "Modificação da superfície de peças em PVC e blendas PVC/ABS para adesão de camadas metálicas." reponame:Repositório Institucional da UFSC, 2014. https://repositorio.ufsc.br/xmlui/handle/123456789/129512.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2014.Made available in DSpace on 2015-02-05T21:11:04Z (GMT). No. of bitstreams: 1 329216.pdf: 2343620 bytes, checksum: bb8bda38a7beb8900267c1a6213bb2e7 (MD5) Previous issue date: 2014
Visando a substituição do terpolímero ABS (acrilonitrila-butadieno-estireno) no processo de cromagem, neste trabalho, foi avaliada a modificação química da superfície de peças injetadas de PVC (policloreto de vinila) puro e blendas de PVC/ABS nas proporções de 20/80, 40/60 e 60/40. As peças foram previamente caracterizadas por ensaios térmicos e mecânicos, como termogravimetria (TGA), calorimetria exploratória diferencial (DSC) e ensaio de tração e submetidas ao pré-tratamento químico sob diferentes condições operacionais, variando-se os reagentes, concentração, temperatura e tempo de tratamento. Para avaliação da modificação ocasionada pelo pré-tratamento na superfície, as peças de PVC puro e das blendas foram analisadas por microscopia eletrônica de varredura (MEV), espectroscopia no infravermelho (FTIR/ATR), microscopia de força atômica (AFM), ângulo de contato e rugosidade. As amostras também foram cromadas e foi avaliada a qualidade da adesão das camadas metálicas, por inspeção visual, adesão e corrosão por névoa salina (salt spray) e os resultados foram comparados com os obtidos para peças em ABS. As alterações ocasionadas na superfície das amostras mostraram ser dependentes da composição do material e das condições operacionais empregadas no pré-tratamento. O PVC apresentou maior resistência química às soluções testadas do que o ABS, necessitando de condições de processo mais agressivas, como temperatura, tempo de imersão e concentração dos reagentes. Blendas com menores concentrações de PVC foram mais susceptíveis ao ataque químico. Superfícies com maior rugosidade e presença de poros, cavidades e reentrâncias distribuídos de forma homogênea, apresentaram melhor adesão da camada metálica. De todas as soluções testadas, a solução condicionante sulfocrômica, quando aplicada no tratamento das amostras de PVC e blendas PVC/ABS de 20/80 e 40/60, em concentração de 350 g/L de ácido crômico e 400 g/L de ácido sulfúrico, temperatura de 70 °C e tempo de imersão de 15 minutos, ocasionou deposição do metal em toda a superfície da amostras, as quais foram aprovadas nos testes de adesão e corrosão.
Abstract : Aiming to replace the terpolymer ABS (acrylonitrile butadiene styrene) in the process of plating, in this work, the chemical modification of the surface of molded pieces of pure PVC (polyvinyl chloride) and blends of PVC/ABS in the proportions of 20/80, 40/60 and 60/40 was evaluated. The pieces were previously characterized by thermal and mechanical tests, such as thermogravimetry (TGA), differential scanning calorimetry (DSC) and tensile test and subjected to chemical pre-treatment under different operating conditions, varying the reagent concentration, temperature and treatment time. To evaluate the modificationcaused by the pre-treatment on the surface, the pure PVC and blends pieces were analyzed by scanning electron microscopy (SEM), infrared spectroscopy (FTIR/ATR), atomic force microscopy (AFM), contact angle and roughness. The samples were also plated and the quality of the adhesion of metallic layers was evaluated by visual inspection, adhesion and corrosion by salt spray and the results were compared with those obtained for ABS pieces. The alterations on the surface of the samples shown to be dependent on the material composition and operating conditions employed in the pre-treatment. PVC showed higher chemical resistance to the tested solutions than ABS, requiring more aggressive process conditions such as temperature, immersion time and concentration of reactants. Blends with lower PVC concentrations were more susceptible to chemical attack. Surfaces with higher roughness and presence of pores, cavities and recesses distributed homogeneously showed better adhesion of the metal layer. Of all solutions tested, the conditioning sulfochromic solution when applied to the treatment of samples of PVC and 20/80 and 40/60 PVC/ABS blends at the concentration of 350 g/L of chromic acid and 400 g/L of sulfuric acid, temperature of 70°C and immersion time of 15 minutes caused the deposition of metal on the entire surface of the samples, which were approved in adhesion and corrosion tests.