É conhecido que, atualmente, o Brasil possui uma demanda substancial de obras de engenharia, como por exemplo, o Trem de Alta Velocidade (TAV) entre as cidades do Rio de Janeiro e de Campinas, necessárias para suportar as presentes e futuras demandas para o desenvolvimento do país. Este projeto governamental do TAV deverá requerer produção elevada de agregados de alta qualidade para emprego como lastro e também para concreto. No tocante ao uso como lastro, o agregado fica exposto e sujeito à ação constante das intempéries, fazendo com que estudos envolvendo alterabilidade sejam tão importantes quanto os de caracterização geomecânica dos materiais pétreos, levando-se em conta as condições intempéricas típicas de uma zona tropical que estarão submetidos. Estas constatações motivaram investigar as relações entre as propriedades tecnológicas de nove tipos de rochas cristalinas (micro-gabro, gnaisse e variedades de granitos) e suas utilizações como lastro do trecho Campinas/São Paulo do traçado do TAV. Em termo práticos, estas rochas foram submetidas a ensaios físicos, mecânicos e de alterabilidade acelerada, sendo que os testes de ciclagem água-estufa foram conjugados aos ensaios de abrasão Los Angeles, choque Treton e esmagamento. Os resultados indicaram que alguns materiais apresentaram valores de resistência inferiores ou próximos aos limites normatizados para lastros de ferrovia, além da perda de qualidade verificada nos ensaios de resistência à intempérie, inviabilizando ou restringindo a utilização de três dos materiais estudados para lastro. De modo geral, tais informações poderão servir de subsídio aos órgãos governamentais para tomada de decisões, quanto ao emprego dos materiais disponíveis na área onde será construído o TAV brasileiro, uma vez que os custos de manutenção da camada de lastro da ferrovia são críticos quando se opta por uma via lastrada ou em laje. / It is well known that Brazil currently shows a high number of engineering projects that are necessary to the development of the country. The projects include the High-Speed Rail (HSR) that will connect Rio de Janeiro and Campinas cities and requires a great production of high-quality construction aggregates to be used in track ballast and also in concrete. In the case of the track ballast, previous studies about the weathering of the aggregates together with a mechanical characterization are important and have to take in consideration that the material will be submitted to weathering conditions typical of a tropical environment. These assumptions motivated the investigation of the technological properties of nine types of crystalline rocks (microgabbro, gneiss and varied granitic rocks) considering their potential to be used as track ballast in the HSR between Campinas and São Paulo. The rock samples were submitted to physical, mechanical and accelerated weathering tests. The soundness by artificial weathering, drying water were conjugated to the Los Angeles abrasion tests, Treton shock and crushing. The results indicate that some materials present resistance values bellow or near the limit normalized for track ballast, besides the loss of the quality verified in weathering resistance tests, making it impossible or restricting the use of the three studied materials as track ballast. In general, such information can be used by government agencies to make decisions about the materials available in the area where the brazilian HSR will be built once the maintenance costs of the track ballast are critical to the choice between a track ballast or slab track.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2018-07-03T13:15:48Z No. of bitstreams: 1 DISSERTAÇÃO CLENIO.pdf: 203355 bytes, checksum: b1a69780d7869294737134153c66d5ae (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-07-03T18:43:19Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO CLENIO.pdf: 203355 bytes, checksum: b1a69780d7869294737134153c66d5ae (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-07-03T18:45:46Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO CLENIO.pdf: 203355 bytes, checksum: b1a69780d7869294737134153c66d5ae (MD5) / Made available in DSpace on 2018-07-03T18:45:54Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO CLENIO.pdf: 203355 bytes, checksum: b1a69780d7869294737134153c66d5ae (MD5) Previous issue date: 2010-03-10 / A obtenção de população adequada na cultura da soja é crucial para um bom cultivo e está relacionada a diversos fatores essenciais. Dentre todos, sementes de boa qualidade é o principal fator a ser levado em conta. Para garantir essa qualidade a produção, comercialização e utilização de sementes seguem o sistema da legislação brasileira. Porém, na agricultura tradicional, ainda é comum o agricultor separar parte de sua produção para utilizar na safra seguinte como semente, podendo apresentar riscos a atividade. O uso de sementes legais é certeza de garantia de qualidade das mesmas, além disso, garantia de evolução da tecnologia de produção, gerando renda, empregos e bem-estar social. O objetivo deste trabalho foi avaliar a qualidade das sementes salvas por agricultores da região sudoeste do Paraná, na safra 2005/2006 e, compará-las com sementes comerciais produzidas pela empresa Lavoura Indústria e Comércio Oeste S/A de Pato Branco-PR, na mesma safra. Entre os dias 03 de outubro e 21 de novembro de 2006 foram coletadas 100 amostras de sementes salvas e produzidas na safra 2005/2006 por agricultores da região Sudoeste do Paraná e também 100 amostras de sementes comerciais produzidas na mesma safra pela empresa Lavoura S.A. da cidade de Pato Branco-PR. Tanto as sementes comerciais como as sementes salvas, foram submetidas à análise de germinação, teste de vigor por envelhecimento acelerado, teste de hipoclorito de sódio para avaliar danos mecânicos e determinação de umidade. As Avaliações mostraram que 20% das cultivares salvas eram registradas para uso e apenas 9% das amostras eram variedades convencionais. A maior parte das sementes salvas foram armazenadas e beneficiadas na propriedade do agricultor, sendo constatada a inadequação desse processo. As sementes comerciais apresentaram elevada superioridade na qualidade fisiológica quando comparadas às sementes salvas. Conclui-se que a utilização de sementes comerciais é vantajosa econômica e socialmente, pois promove o agronegócio e, principalmente, o agricultor é beneficiado com a garantia de boa implantação da lavoura. / To obtain adjusted population in the culture of the soybean is crucial for a good crop and is related to various essential factors. Seeds of good quality are the main factor to well succeeded in growing crops. To guarantee this quality, the production, commercialization and use of seeds follow the brazilian system legislation. However, in traditional agriculture, the producer uses separate part of its production to as seed. So, there is a lot of risks as for as they use saved seeds. The use of legal seeds is certainly a quality assurance of the crops, moreover, guarantee of evolution of the technology, generating income, jobs and welfare state. The objective of this work was to evaluate the quality of saved seeds for grower of the southwestern region of Paraná state, in the crop year of 2005/2006 and compare them with commercial seeds produced by the company Farming Industry and Commerce West S/A of Pato Branco, in the same period. Between 03 of october and 21 of november of 2006 it was collected 100 samples of saved seeds produced in the crop year of 2005/2006 for producers of the Southwestern region of Paraná and also, 100 samples of commercial seeds of the same period for the company Lavoura S.A. of the Pato Branco city. All samples were submitted to the germination test, accelerated aging test, sodium hypoclorite test for evaluating mechanical damages and seed moisture content. These evaluations had shown that 20% of the saved seeds were registered for use and only 9% were conventional varieties. Most of the saved seeds had been stored and processed in the own area of the producer, and probably quality was lower considering bad storage and processing. The commercial seeds showed better physiological quality when compared to saved seeds. It was concluded that the use of commercial seeds is advantageous, economic and socially, promote the agribusiness and, mainly, the producer is with the guarantee of good implantation of the crop area.

Este trabalho apresenta uma avaliação da degradação ambiental da área entorno do igarapé do Tucunduba. O igarapé do Tucunduba, por estar situado na área de expansão da cidade e caracterizado por um processo de urbanização acelerado, ocupada por uma população de baixa renda, especuladores e segregados e com total carência de serviços de infra-estrutura, como: água encanada, esgoto e coleta de lixo. O igarapé do Tucunduba, que é um dos 13 canais da bacia hidrográfica urbana do Tucunduba situa-se a uma latitude de 1 26 4,7 e a uma longitude de 48 27 20,9, que corresponde a sua nascente, é o principal corpo hídrico dessa bacia, possuindo extensão linear de aproximadamente 3900m, tendo seu exutório no Rio Guamá na parte litorânea da cidade. O aplicativo computacional Corel Draw X4 V14.0 foi utilizado para elaboração dos mosaicos das diversas imagens dos anos de 1972, 1977, 1998 e 2006, que foram importados e, posteriormente, exportados para o ArcGIS 9.0 para a interpretação da evolução urbana nas diversas imagens utilizadas. Os mapas resultantes revelaram um processo de urbanização acelerada no entorno do igarapé e consequentemente, diminuição da área verde, que em 1972 era de 3,4 km2 e em 2006 reduz-se para de 0,4 km2. Por meio de análise das fotografias de campo foi possível se registrar os impactos ambientais provocados por invasores que se apropriaram da área. Por meio de criteriosa análise documental foi possível se comprovar a degradação e contaminação do igarapé, além de se avaliar às obras de macrodrenagem executadas no igarapé, que naturalmente geram impacto ambiental negativo. Enfim, no estudo sobre urbanização realizada por meio da elaboração de mapas temáticos, foi possível se observar o rápido adensamento populacional no igarapé do Tucunduba e a consequente redução 755% da área de vegetação do igarapé, no período de 1972 para 2006, ocasionando assoreamento, provocado por aterros e resíduos sólidos inclusive metais pesados, retirada da vegetação para uso como lenha, construções e outros finalidades. Todos estes contribuíram para poluição e a degradação ambiental das águas como um todo. / This essay presents synthetically an evaluation of environmental degradation of the surrounding areas of draining basin of Tucunduba Creek. This river basin comprises an important section of Belem (Pa) city, occupied and dwelled irregularly in a rushing process of forced and undue urbanization. These areas settled usually by a low income, speculators and segregated population, overwhelmed by a complete absence of fundamental urban services as : running water, sewerage and garbage disposal. This waterway, besides thirteen (13) other ones, form the so called urban watershed of Tucunduba, having its original springs at 1 26 4.7 S of latitude, and 48 27 20.9 W of longitude. It is the main streamlet of the basin, with roughly 3,900m (Three Thousand and Nine Hundred Meters) in lenght, flowing towards Guamá river in the waterfront of the city. During the assembling and making of segments (mosaics) we used Corel Draw X4 V14.0, a computer aided application, using several footages, shot in the years 1972,1977,1998 and 2006, where they were imported from. In the sequence, exported to Arc Gis 9.0 for interpretation of the urban growth along the period involved. The resulting maps in the aftermath, revealed a rushing and disordinated occupation process, spreading throughout the draining basin, provoking consequently a huge decrease of green covered areas. In numbers, these areas were of 3.4 km in the year 1972 ; in 2006 they had roughly 0.4 km. Through field shots it was possible to register the environmental impacts provoked by irregular settlers. According to criterious documental analysis it becomes clear and evident the degradation and contamination of the creek besides the evaluation of negative environmental impacts of macro-draining works carried out in the area. Conclusively, in the present urbanization studies, after plotting of thematic maps, we can easily observe the increasing densification of settlers in the Tucunduba creek, and consequent reduction of 755% of vegetation area during 1972 to 2006 period, causing a silting up of river bed, due to irregular earthworks, solid residues casting, including heavy metals, deforestation or clearcutting for firewood, construction, and for other purposes. All these factors contributed for the pollution and environmetal degradation of the waters as a whole.

O entendimento dos mecanismos de degradação que agem sob os nanocompósitos poliméricos frente ao intemperismo (luz UV, calor, oxigênio, chuva ácida, entre outros), é o ponto chave para o desenvolvimento de novos aditivos e novas aplicações. Para este trabalho a síntese do nanocompósito foi realizada no estado fundido, utilizando-se uma extrusora de dupla rosca. A matriz polimérica utilizada foi o HMS-PP (polipropileno com alta resistência do fundido) sintetizado por irradiação gama e a argila Montmorilonita. Para melhor compatibilização entre a matriz e a nanocarga, foi utilizada o agente compatibilizante andrido maléico. Para os ensaios de envelhecimento ambiental e acelerado em estufa, os corpos de prova foram confeccionados por meio de termoprensagem. A caracterização dos efeitos da adição de argila e do envelhecimento nos nanocompósitos, presupôs o emprego das técnicas de ensaios mecânicos, Calorimetria Diferencial Exploratória (DSC), Termogravimetria (TGA), Espectroscopia no Infravermelho por Transformada de Fourier (FT-IR), Espectrometria de Fluorescêcia de Raios X por Dispersão de Comprimento de Onda (WDXRF), Microscopia Eletrônica de Varredura (MEV), Índice de Fluidez (IF), Difração de Raios-X (DRX) e Espectroscopia de Energia Dispersiva (EDS). Foram ensaiadas amostras com 0,1; 1; 3; 5 e 10% de argila. A amostra com porcentagem de 5% de argila demonstrou uma melhor estabilidade frente ao ensaio de envelhecimento ambiental e no envelhecimento acelerado em estufa. Por outro lado na amostra com maior porcentagem de argila (10%) ocorreu o inverso, sob ensaio ambiental houve maior degradação e sob envelhecimento acelerado em estufa, manteve-se resistente até 56 dias de envelhecimento. Nas porcentagens estudas (menor que ≤ 3%) de argila, pode-se constatar um equilíbrio entre o efeito barreira da argila e a ação dos íons metálicos que aceleram o processo degradativo. / The understanding of degradation mechanism action on the polymer nanocomposites in face of weathering (UV light, heat, acid rain, among others), is the key for development of new additives and new applications. In this work the nanocomposite synthesis was carried in molten state, using twin-screw extruder. The polymer matrix was the HMS-PP (high melt polypropylene) synthesized by gamma irradiation and the nanometric inorganic component was the montmorillonite clay. For better compatibilization between the matrix and clay, it were used maleic anhydride as coupling agent. For environment and in oven accelerated aging assays, the dumbbell samples were prepared under hot pressing. The characterization of clay addition effects and aging effects on the nanocomposites, required the use of techiniques of Differential Scanning Calorimetry (DSC), Thermogravimetry (TGA), Fourier Transformed Infrared Spectroscopy (FT-IR), Xray Fluorescence (WDXRF), Scanning Eletron Microscopy (SEM), Energy Dispersive Spetroscopy (EDS) and mechanical properties. Samples with 0.1; 1; 3; 5; 10 % of clay were tested. The sample with 5% of clay showed better stability on the environmental assay and accelerated aging in oven assay. On the other hand, the sample with higher percent of clay (10%), was more degraded under on environmental aging than under accelerated aging in stove. In this case, became more resistant until 56 days of assay. On the studied concentrations (less than ≤ 3%) of clay, it can be seen an equilibrium between barrier effect and metallic ions action accelerating the degradative process.

Os ensaios acelerados de pavimentos em escala real consistem na aplicação controlada de uma carga de roda igual ou acima da carga máxima legal permitida, em uma estrutura de pavimento, seja este um pavimento-teste ou uma via existente, para se determinar a resposta do sistema e o seu desempenho sob condições controladas e aceleradas de acúmulo de danos num espaço limitado de tempo (METCALF, 1996). Esses ensaios podem ser realizados hoje, tanto por simuladores instalados em campos de prova destinados a este único fim, quanto por simuladores móveis, cuja composição é rebocável ou autopropelida e pode ser posicionada no local a ser pesquisado, o que se mostra especialmente vantajoso no estudo de materiais e técnicas de restauração de pavimentos por preservar as condições de contorno. Apresentam-se os resultados dos primeiros testes acelerados em pavimentos com simulador de tráfego linear móvel no Brasil e suas contribuições para o desenvolvimento das técnicas, processos de projeto e planejamento rodoviários. Apresenta-se também uma síntese dos ensaios acelerados de pavimentos em escala real com simuladores de tráfego lineares móveis, com o objetivo de mostrar o estágio atual do conhecimento nessa área, a partir de uma revisão bibliográfica e associando esses conhecimentos a casos práticos. Como contribuição para futuros trabalhos, com base na análise das pesquisas já finalizadas e dos resultados já obtidos, foi elaborada uma proposta de método para a realização de simulação em pista e de ensaios a serem conduzidos antes, durante e após o término da simulação, dependendo do objetivo específico dos ensaios acelerados. / Full-scale accelerated pavement testing is defined as the controlled application of a wheel load in a pavement structure to determine the pavement system response and its performance under accelerated conditions of accumulated damage in a compressed time period (METCALF, 1996). Loads at or above the legal maximum allowed by highway agencies can be applied at test tracks, using simulators designed solely for this purpose, or at existent roads using mobile simulators positioned right at the road pavement structure. This layout provides an interesting advantage in the study of materials and pavement rehabilitation techniques by preserving field conditions, specially structural and environmental characteristics. This research describes the results from the first accelerated pavement tests with mobile linear traffic simulator in Brazil and their contribution for the development of design procedures, distress monitoring methods, and road planning. As part of this research, a wide literature review was done associated with practical case studies, the current stage of knowledge in this area, and a real scale synthesis of accelerated pavement experiments with linear mobile traffic simulators. This research proposes a simulation method for testing pavement sections and the evaluation tests to be performed according to the objective of the accelerated pavement test study. This research is a contribution to the state of practice of this type of accelerated pavement testing in Brazil and outlines the path for future applications of this technology in the country.

O presente trabalho teve como objetivo analisar “in vitro” a alteração de cor e a rugosidade superficial de uma resina composta (Charisma®) submetidas a tratamento clareador com agente clareador Lase Peroxide Sensy® (CC) e grupo controle sem tratamento clareador (SCL), após envelhecimento (EAA) em função do tempo, realizando-se avaliação superficial complementar por meio de Microscopia Eletrônica de Varredura (MEV) e EDX. Os corpos-de-prova (n=15) foram confeccionados com o auxílio de uma matriz de Teflon nas dimensões de 11x2,0mm, polidos com discos Soft Lex®, na seqüência de abrasividade decrescente e armazenados em saliva artificial a 37ºC (±1ºC), até os momentos de serem submetidos aos tratamentos propostos e à realização das leituras de alteração de cor e rugosidade superficial, nos tempos: 24 horas após a confecção (T0), após envelhecimento artificial acelerado (T1), 24 horas após clareamento (T2), 7dias (T3) e 1 mês após clareamento (T4). As leituras de alteração de cor foram obtidas com o auxílio do aparelho Espectrofotômetro (PCB6807BYK GARDNER) e para as leituras de rugosidade superfícial foi utilizado o Rugosímetro Mitutoyo SJ201P. Os dados foram submetidos à Análise de Variância ANOVA (p≤0,05). Os resultados obtidos foram: a) o fator Tempo teve efeito estatisticamente significante sobre as variáveis ΔE* (T1=T2=T3; T1=T4), L* (T0<T1=T2=T3=T4), a* (T0>T1=T2; T1=T3=T4; T4>T2), b* (T0>T1=T2=T3; T4=T3=T1; T2<T4) e rugosidade superficial (μm) (T0<T1,T2,T3,T4; T1=T2; T1<T3=T4; T2=T3=T4; b) para o fator tratamento com relação a ΔE* e fator L*(CC>SCL), para os fatores a* e b*(CC<SC), c) a interação Tratamento x Tempo não apresentou diferença estatisticamente significante para as variáveis ΔE*, L*, a*, b* e rugosidade superficial, d) as superfícies após EAA apresentaram alterações d) não houve mudanças no EDX antes e após os tratamentos. Conclui-se que a resina Charisma®, apresentou alteração de cor (ΔE*>3,3) e uma estabilidade na rugosidade superficial a partir de T2. / The current study in vitro evaluated the color change and surface roughness of the composite resin Charisma® cleared with Lase Peroxide Sensy® (CCL) and control without bleaching (SCL) after accelerated artificial aging (EAA) as a function of time, performing additional surface evaluation by scanning electron microscopy (MEV) and EDX. To obtain the color change and surface roughness a Spectrophotometer (PCB 6807 BYK GARDNER) and rugosimeter (Mitutoyo SJ- 201P) were employed respectively. Measurements were carried out at five times: 24 hours after preparation (T0), after artificial accelerated aging (T1), 24 hours after bleaching (T2), 7days (T3) and 1 month after bleaching (T4). The specimens (n=15) were prepared with aid of a Teflon (10-mmin diameter and 2mm thick). The specimens were polished with discs Soft Lex®, following abrasiveness decreased, being stored in artificial saliva at 37ºC (±1ºC) until the time of undergoing the proposed treatments and the measurements. The data obtained were submitted to ANOVA parametric test (p ≤ 0.05). The results were: a) time factor had a statistically significant effect on the variables ΔE* (T1 = T2 = T3, T1 = T4), L*(T0 <T1 = T2 = T3 = T4), a* (T0 > T1 = T2; T1=T3 =T4, T4>T2), b* (T0> T1=T2=T3, T4=T3=T1; T2<T4) and roughness(μm) (T0<T1,T2, T3,T4; T1 = T2; T1<T3=T4; T2=T3=T4), b) for treatment factor ΔE* and L* (CC> SCL) for the factors a*and b* (CC <SC), c) Treatment x Time interaction showed no statistically significant difference for the variables ΔE*, L*, a*, b* and surface roughness, d) after EAA the surfaces change d) before and after EAA dont have changes. It is concluded that the resin Charisma®, presented color change (ΔE *> 3.3) and surface roughness stability from T2.

Orientador: Franco Giuseppe Dedini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-24T21:14:00Z (GMT). No. of bitstreams: 1 NacerColmenero_Alberto_M.pdf: 9387560 bytes, checksum: 8ce3464ab75b288b4b8a9e8615aa96da (MD5) Previous issue date: 1999 / Resumo: Neste trabalho apresenta-se um estudo sobre os aspectos básicos relacionados com os ensaios acelerados utilizados na industria, são apresentados alguns conceitos fundamentais para o melhor entendimento da temática, as relações estresse x vida e distribuições de vida mais utilizadas. Do estudo realizado, foi escolhida uma metodologia para analisar os ensaios acelerados de vida, diferente à que é empregada em muitas industrias atualmente, baseada em um tipo de planejamento aleatorizado por níveis. Por último é apresentado um programa para o processamento dos dados provenientes de ensaios acelerados com estresse constante e modo de falha simples, para dados completos, e com censura a direita ou múltipla, utilizando a distribuição de Weibull, Log-normal e Normal, combinadas com os modelos mais utilizados (Arrhenius e Lei da Potência Inversa), o programa permite o processamento dos dados dos ensaios acelerados por dois métodos, Mínimos Quadrados e Máxima Verossimilhança, o primeiro oferece os estimados iniciais para aplicar o método de Máxima Verossimilhança, e assim assegurar a convergência do método de Newton-Raphson para todos os casos. Outras saídas do programa são; gráficos de residuais, de probabilidades vs. tempo, estresse vs. percentuais, etc. No programa são utilizados testes estatísticos para a validação dos ensaios, dando a possibilidade de utilizar diferentes níveis de confiança para calcular os intervalos de confiança dos parâmetros utilizados / Abstract: This work presents a study on the basie aspects related with the accelerated tests used in the industry, some fundamental concepts are presented for the best understanding of the thematic, the relationships stress x life and the more applied life distributions. A methodology was chosen to analyze the accelerated life tests, different from that commonly applied now in a lot of industries, based on a type of ramdomic planning by levels. Last a software is presented for the processing of the accelerated tests data with constant stress and simple failure mode, for complete data, and with right or multiple censored tests, using the Weibull, Log-normal and Normal distributions, combined with the most used models (Arrhenius model and the Inverse Power Law), the program allows the processing of the accelerated tests data by two methods, Minimum Square and Maximum Likelihood, the first offers the evaluated initial values to apply the method of Maximum Likelihood, and in this way to assure the convergence of the method of Newton-Raphson for alI the cases. Other outputs of the software are; graphs of the residual, probabilities vs. time, stress vs. percentile, ete. In the program, statistical tests are used for the validation of the tests, giving the possibility to use different confidence levels to calculate the confidence intervals of the parameters of interest / Mestrado / Projeto Mecanico / Mestre em Engenharia Mecânica

Les matériaux polymères ont de nombreux avantages comme la légèreté, le coût, la formabilité… mais sont aussi à l’origine de certains problèmes environnementaux actuels. La substitution des polymères conventionnels d’origine pétrochimique et non biodégradables par des polymères biosourcés et biodégradables tels que le polylactide (PLA) ou les polyhydroxyalcanoates (PHA) peut apparaître comme une alternative crédible. Cependant, un des freins à leur développement demeure la faible connaissance de la durée de vie de ces biopolymères lorsqu’ils sont exposés à différents types d’environnements, en particulier en milieu marin si l’on considère une application marine. Dans le cadre de cette étude, il a donc été entrepris de suivre le vieillissement naturel et le vieillissement accéléré du PLA et des PHA en milieu marin dans l’objectif d’appréhender les mécanismes et les cinétiques de dégradation. Dans le but de découpler les effets liés à l’eau, aux sels minéraux et aux microorganismes, les échantillons ont été immergés dans différentes conditions, i.e. en eau distillée, en eau de mer naturelle et en eau de mer filtrée et renouvelée à différentes températures. L’influence du milieu sur la dégradation de ces biopolymères est analysée et discutée, de même que l’influence de la géométrie des pièces (films de différentes épaisseurs, éprouvettes ou fibres). Enfin, la prédiction de la durée de vie de ces polymères a été envisagée par l’intermédiaire de deux approches, conduisant à une estimation de leur durabilité dans un milieu bien défini et au regard d’une propriété donnée. / Pollution of nature by plastics is a major environmental problem and better management of the lifetime of polymers is a major challenge for the future. In recent years, bio-based and biodegradable polymers, such as polylactide (PLA), or polyhydroxyalkanoates (PHA) have appeared as an alternative solution in order to solve these problems. One of the limits remains the relative lack of knowledge of their lifetime and degradation behaviour in aqueous environments, and more specifically in the marine environment. In this study natural and accelerated ageing tests were performed under several conditions, distilled water, filtered and renewed seawater and natural seawater, at different temperatures, in order to decouple enzymatic and hydrolytic mechanisms. The aim of this study is to establish a baseline on degradation mechanisms and kinetics, in order to make lifetime predictions of biopolymer behaviour in seawater.Degradation phenomena have been identified. Biodegradation tests were also performed in a marine environment by following the release of CO2. Then, lifetime predictions of the properties of these biopolymers at seawater temperature were made using two different approaches.

Posttraumatic Stress Disorder (PTSD) is a prevalent anxiety disorder that is debilitating to both veterans and civilians following one or more traumatic events. Sleep disturbances are hallmark features of PTSD. Sleep disturbances and PTSD remain two significant PTSD-related issues that continue to plague veterans returning from active duty, thereby preventing full reintegration into society. The same problem exists for civilians. This research was conducted as a previously collected pilot study data and a secondary data analysis. The purpose of the study consisted of: 1) examining the impact of treatment with Accelerated Resolution Therapy (ART) on symptoms of PTSD and sleep disturbances; 2) examining the relationships and treatment response among both subjective and objective measures of sleep function; and 3) comparing the relationship between PTSD and sleep disturbances among military versus civilians, including the effects of treatment with ART. The study represents one of only a few studies consisting of subjective measures of PTSD (PCL checklist) and sleep quality (Pittsburgh Quality Sleep Index (PSQI)), and objective measurement of sleep function by use of electroencephalography (EEG) testing and based on a 30-minute nap protocol. The aims of this study were to: 1) investigate the effects of ART on comorbid PTSD and sleep disturbances in U.S. veterans measured both subjectively (self-report) and objectively (sleep EEG data) from previously collected pilot study data; 2) assess the relationships between objective and subjective measures of sleep disturbances before and after treatment with ART for symptoms of PTSD in U.S. veterans from previously collected pilot study data; and 3) compare self-report PTSD and sleep disturbances symptoms between civilians and veterans before and after treatment with ART using a secondary analysis from two previously conducted studies. For Specific Aims 1 and 2, the methods consisted of previously collected pilot study data of 8 veterans who were treated with ART at the University of South Florida, College of Nursing. For Specific Aim 3, data were pooled from two completed studies of ART directed by Dr. Kevin Kip that included civilians (n=75) and veterans (n=50) who were treated for PTSD. Data analysis for Aim 1 included the use of paired t tests to compare PSQI score and each stage of sleep measured from qEEG (Delta, Theta, Alpha, Beta, Gamma) before and after treatment with ART. For Aim 2, Pearson correlation was used to assess the relationship between objective measurement of sleep disturbances and subjective sleep quality before and after ART. For Aim 3, multiple linear regression models were fit with PSQI (sleep) score as the dependent variable, PCL (PTSD) score as the primary independent variable, along with a main effect term for military status (civilian versus military) and an interaction term (military status * PCL score). Results for aims 1 and 2 showed the mean age of the sample to be 37.6 years, 87.5% male, 87.5% White (non-Hispanic), 87.5% had experienced prior combat, 50% had experienced 5 or more traumatic memories that impacted their lives, and 87.5% had previous treatment for PTSD. Sample mean scores were above established screening criteria for PTSD (PCL-M = 63.7), sleep disturbance (PSQI = 14.5), and Center for Epidemiologic Studies Depression Scale (CES-D = 28.9). For Aim 1, after treatment with ART, the mean score on the PSQI dropped 4.88 points, mean score on the PCL-M dropped -30.13 points, thereby indicating significant reductions in sleep dysfunction and symptoms of PTSD. Mean Delta 1.5-3.5 Hz waves increased pre/post by 299.89 (p=.032), and Theta 4-6.5 Hz waves increased pre/post mean by 83.07 (p<0.001), both indicative of improved sleep quality. Results for Aim 2 showed statistically significant strong inverse correlations between PSQI and Theta 1.5-3.5 Hz waves (r=-0.79) and PSQI and Alpha 8-11 Hz waves (r=-0.89) at baseline. Post-ART, non-significant trends were observed for higher PSQI scores and higher Beta (conscious, alert) waves. For Aim 3, mean age of military participants (n=50) was 41.9 years versus 40.4 years among civilians (n=75, p=.439). For the military cohort, 18% were female compared to 80% among civilians (p<0.001), with lower Hispanic ethnicity among military compared to civilian participants (12% vs. 27%, p=0.04). In multiple regression analysis, change in PCL score was a strong predictor of change in PSQI score, regardless of military status PCL. In summary, within the setting of PTSD, military participants tend to present with different traumatic exposures and worse sleep quality compared to civilian counterparts. In spite of these differences, the treatment protocol with ART demonstrated similar level of benefit (reduction in symptoms of PTSD and sleep disturbance) for both military and civilian personnel. Thus, nurses caring for individuals with PTSD, whether military or civilian, need to routinely assess sleep disturbances and initiate an open dialogue regarding these conditions. In return, nurses will be able to provide patients with resources to help them better understand and address these concerns, including after experiencing restless nights of sleep. Lastly, nurses should recognize the bi-directional temporal relationship between PTSD and sleep disturbances places. This places a premium on assessing these conditions collectively, rather than as discrete, independent clinical conditions.

I examine three issues related to internal control reporting by non-accelerated filers. Motivation for the three studies comes from the fact that Section 404 of the Sarbanes-Oxley Act (SOX) continues to be controversial, as evidenced by the permanent exemption from Section 404(b) of SOX granted to non-accelerated filers by the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010. The Dodd-Frank Act also requires the SEC to study compliance costs associated with smaller accelerated filers. In the first part of my dissertation, I document that the audit fee premium for non-accelerated filers disclosing a material weakness in internal controls (a) is significantly lower than the corresponding premium for accelerated filers, and (b) declines significantly over time. I also find that in the case of accelerated filers remediating clients pay lower fees compared to clients continuing to report internal control problems; however, such differences are not observed in the case of non-accelerated filers. The second essay focuses on audit report lag. The results indicate that presence of material weaknesses are associated with increased audit report lags, for both accelerated and non-accelerated filers. The results also indicate that the decline in report lag following remediation of problems is greater for accelerated filers than for non-accelerated filers. The third essay examines early warnings (pursuant to Section 302 disclosures) for firms that subsequently disclosed internal control problems in their 404 reports. The analyses indicate that non-accelerated firms with shorter CFO tenure, presence of accounting experts on the audit committee, and more frequent audit committee meetings are more likely to provide prior Section 302 warnings. Overall the results suggest that there are differences in internal control reporting between the accelerated and non-accelerated filers. The results provide empirical grounding for the ongoing debate about internal control reporting by non-accelerated filers.