Дисертації з теми "PV1"
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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/.
Повний текст джерелаAutoimmune 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.
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.
Повний текст джерелаCabrera, 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.
Повний текст джерелаAmaral, 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/.
Повний текст джерелаIn 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.
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/.
Повний текст джерелаThe 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.
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.
Повний текст джерелаThe 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
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.
Повний текст джерелаMade available in DSpace on 2014-10-09T14:06:12Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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.
Повний текст джерелаShapla, 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.
Повний текст джерелаJunkunlo, 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.
Повний текст джерелаRodrigues, 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.
Повний текст джерелаIn 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.
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.
Повний текст джерелаIn 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%
Савчук, Б. П. "PVC Compounds." Thesis, Київський національний університет технологій та дизайну, 2017. https://er.knutd.edu.ua/handle/123456789/7389.
Повний текст джерелаVelazquez, 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.
Повний текст джерелаThe 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.
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.
Повний текст джерелаLindberg 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.
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.
Повний текст джерелаVess, Lora Elizabeth. "The politics of PVC /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2007. http://hdl.handle.net/1794/6195.
Повний текст джерелаTypescript. 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.
Joss, Victoria. "Surface treatments of PVC." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398489.
Повний текст джерелаGreer, Emma. "Mechanistic studies on Ph1." Thesis, University of East Anglia, 2011. https://ueaeprints.uea.ac.uk/35555/.
Повний текст джерелаSilva, Carolina Branco Alves. "Equity research - PVH Corp." Master's thesis, Instituto Superior de Economia e Gestão, 2019. http://hdl.handle.net/10400.5/19482.
Повний текст джерелаO 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
Merriman, Carolyn. "Peripheral Vascular System (PVS)." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/8533.
Повний текст джерелаWuyts, Shirley Lynne. "SAR processing using PVM." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/21763.
Повний текст джерелаThis 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.
Vess, Lora Elizabeth 1972. "The Politics of PVC." Thesis, University of Oregon, 2007. http://hdl.handle.net/1794/6195.
Повний текст джерелаThis 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
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/.
Повний текст джерелаThe 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.
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.
Повний текст джерелаFinanciadora de Estudos e Projetos
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.
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.
Повний текст джерелаTitle from PDF t.p. (viewed May 17, 2010). Advisor: Srinivasan Vijayaraghavan. Keywords: sperm; spermatogenesis; PP1gamma2; PP1gamma1; mice; transgene. Includes bibliographical references (p. 102-123).
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.
Повний текст джерелаValue-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]
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/.
Повний текст джерелаHydrogels 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.
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.
Повний текст джерелаdos, 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.
Повний текст джерелаFaculdade 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
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.
Повний текст джерела--- 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
Cook, Joseph P. "PVP Microgels : Theory and Applications." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520970.
Повний текст джерелаAugustsson, 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.
Повний текст джерелаProgram: Textilingenjörsutbildningen
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.
Повний текст джерелаAraújo, 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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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.
Caldart, Leandro. "Gestão de resíduos de PVC." Florianópolis, SC, 2005. http://repositorio.ufsc.br/handle/123456789/103053.
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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.
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.
Повний текст джерелаRosecký, Pavel. "Analýza životnosti střešních PVC fólií." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392321.
Повний текст джерелаHanco, 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.
Повний текст джерелаTesis
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.
Повний текст джерелаApproximately 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]
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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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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/.
Повний текст джерелаThe 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.
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/.
Повний текст джерелаResveratrol (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.
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/.
Повний текст джерелаThe 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.
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.
Повний текст джерелаPlasticized 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
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.
Повний текст джерелаAtlan, 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.
Повний текст джерелаNon communiqué
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.
Повний текст джерелаThe 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
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.
Повний текст джерелаKurek, 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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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.