Apesar das vantagens relacionadas ao uso de estruturas de contenção em solo reforçado, a maioria das obras em nosso país ainda é executada por soluções convencionais. A ausência de um conhecimento mais profundo sobre o real comportamento das estruturas em solo reforçado, principalmente em termos de deslocamentos, certamente impede uma utilização mais intensa desse tipo de obra no Brasil. Com isso, para contribuir para um melhor entendimento do desempenho de estruturas em solo reforçado, foram construídos oito protótipos de estrutura de contenção em solo reforçado com geotêxtil, com 4,0 m de altura cada. Todas as estruturas foram instrumentadas, principalmente visando os deslocamentos, para avaliar o comportamento de campo. Adicionalmente, foi realizada a análise, em longo prazo, de um talude íngreme com 15,3 m de altura, construído no estado americano de Idaho, em que foram realizadas leituras até cinco anos após o fim da construção. Esse trabalho apresenta os resultados de cada protótipo construído, juntamente com os resultados do talude íngreme em Idaho, tanto em curto, quanto em longo prazo. As análises desenvolvidas compreendem, além da avaliação dos resultados individuais de cada estrutura, uma análise paramétrica entre todos os protótipos, investigando entre outros fatores, o tipo de solo, tipo de geossintético e geometria interna das estruturas. Além disso, foi realizada uma abordagem especial sobre a análise em longo prazo do protótipo 7. Dentre as conclusões mais importantes obtidas nesta pesquisa, podem-se citar as grandes deformações de fluência registradas no protótipo 7, a tendência de formação de uma superfície potencial de ruptura linear para os protótipos construídos com solo granular e de espiral logarítmica para os protótipos construídos com solos coesivos, a importância da coesão no bom comportamento das estruturas e a redução das movimentações verticais das estruturas com o acréscimo do teor de areia na granulometria do solo / Despite the important advantages associated with the use of geotextiles as reinforcement, most retaining walls in Brazil still use more conventional. The lack of field monitoring data regarding the internal and face displacements of these structures has certainly prevented broader use of this reinforced soil technology. This study addresses several aspects related to the behavior of geotextile-reinforced soil structures, such as the deformability of reinforcement materials under the confinement of soil, and quantification of the actual failure mechanisms. To achieve these goals, eight 4.0 m high geotextile-reinforced soil retaining wall prototypes were built and instrumented in order to quantify their behavior under ambient atmospheric conditions. Granular and poorly draining backfills were used in this study. Innovative construction methods and instrumentation were developed specifically for this research program. A significant laboratory testing program was conducted to quantify the stress-strain properties of the soils and geosynthetics involved in the construction of the walls. As a reference, the behaviors of these prototype structures were compared with that of a long term analysis of a steep slope in Idaho, USA. This wall is 15.3 m high, with displacement measurements carried out until five years after the end of the construction. A parametric analysis was conducted for the prototypes, in order to investigate the effects of soil type, reinforcement type and internal geometry of the structures. Among the most important conclusions obtained in this research, it is the large creep strains observed in prototype 7, the tendency of a linear potential slip surface observed for the walls constructed with granular backfills, and a log spiral slip surface for the prototypes constructed with cohesive backfills, the importance of the apparent cohesion in the behavior of the structures, and the reduction of the vertical movements of the structures with the increase of the amount of sand in the grain size distribution of the soil

An appreciation of the extent of syndepositional fracturing, faulting, and cementation of carbonate platform margins is essential to understanding the role of early diagenesis and compaction in margin deformation. This study uses integrated lidar and outcrop data along the Capitan Reef from an area encompassing the mouths of both Rattlesnake and Walnut Canyons. Mapping geomorphic expressions of syndepositional faults and fractures at multiple scales of observation was the main approach to delineating zones of syndepositional fractures. Ridge- groove couplets visible in exposures of the Capitan Reef throughout the Guadalupe Mountains were targeted because the ability to identify these as signs of syndepositional fracture development would have implications for the entire reef complex. Results show that these ridgegroove couplets are the product of differential weathering of syndepositional as well as burial-related fractures. Recessive grooves have an average syndepositional fracture spacing of ~13 m whereas ridges have a spacing of ~33 m. vi Smaller (~5-20 m-wide) scale erosional lineaments common in the study area and mappable on airborne lidar are formed by differential erosion of planes of syndepositional faults. Maps of these fault lineaments on the lidar show that syndepositional faults extend laterally for 300 m - 2000 m and relay near the terminations of the faults at each end. Faults can be further grouped into fault systems consisting of sets of faults connected by fault relays that extend for at least the entire length (~12 km) of the study area. Although vertical displacement along faults is typically less than 11 m, syndepositional faults result in changes in structural dip domain of 1-6 degrees across an individual fault. Even smaller erosional lineaments (10 cm-1 m) are visible on the airborne lidar that form as a result of differential erosion of individual fractures. Larger fractures (> 20 cm) can be reliably mapped on the lidar, but smaller features (< 20 cm) cannot be reliably mapped with currently available data and can only be captured using field studies. Fracture fill types are heterogeneous along strike as shown by comparisons of field study locations. Siliciclastic-dominated fills are likely sourced from overlying siliciclastic units of the shelf, which, in this area, were from the Ocotillo Siltstone. These silt-filled fractures are broadly distributed, indicating preferential development and infill of syndepositional fractures during the deposition of the Ocotillo Siltstone in the G27/28 high-frequency sequences. Development of early fractures is also shown to have been influenced by mechanical stratigraphy with changes in fracture spacing between massive to thick-bedded shelf-margin (~17 m fracture spacing) and outer-shelf facies tracts versus thin-bedded outer-shelf and shelf-crest (~28 m fracture spacing). Ultimately, this study demonstrated that the Capitan shelf margin was ubiquitously overprinted by syndepositional fracturing and faulting and that this nearsurface structural modification influenced early diagenetic patterns and internal vii sedimentation throughout the reef margin. Before this study, the extent and nature of syndepositional fracture/fault development within the margin were largely unquantified. Here, by integrating field observations and surface weathering reflections of these fractures as observed in the lidar, we can demonstrate a widespread impact of early fracturing more akin to analogous early-lithified margins such as the Devonian of the Canning Basin of Australia. / text

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nas últimas três décadas, a busca por combustíveis alternativos e renováveis teve maior evidência no cenário mundial, devido as crescentes preocupações ambientais e com a perspectiva de esgotamento de fontes energéticas de origem fóssil. A produção de biomassa de micro-organismos tem sido sugerida como adequada para a conversão em energia. Este trabalho teve como objetivo avaliar o potencial biotecnológico de amostras de Aspergillus spp. isolados da Caatinga através da seleção entre dez amostras do gênero, sendo Aspergillus niger (3) A. flavus (3), e A. parasiticus (4). Foram realizadas extrações dos lipídeos totais e a amostra com melhor percentual realizou-se a cinética de crescimento, caracterização dos ácidos graxos e atividade antioxidante da amostra selecionada. As amostras foram cultivadas em meio sintético Czapek líquido, e em meio alternativo (milhocina e melaço de cana-de- açúcar), utilizando o planejamento fatorial completo 23. Os lipídeos totais foram extraídos utilizando combinação binária de clorofórmio e metanol. Foram obtidas quantidades de lipídeos totais acima de 20% em ambos meios de cultura, caracterizando o gênero Aspergillus como oleaginoso. Os resultados indicaram que o Aspergillus parasiticus UCP 1182, obteve uma produção de 2,03 g/L de biomassa e uma produção de 44,2% de lipídeos totais em Meio Czapek, enquanto na produção em meio alternativo (melaço de cana-de açúcar e Milhocina) obteve no ensaio (8) 2,83g de biomassa em 48,9% de lipídeos totais. O perfil dos ácidos graxos cultivado em meio Czapek indicou a presença de ácido graxos linolêico (36,54%) e oleico (33,95%). E no meio alternativo o composto favoreceu a produção do acido graxo linolênico (28,66%) e ácido linolêico (40%). Na atividade oxidante do A. parasiticus calculada em regressão linear, obteve o EC50 de 4,06774 &#956;g/mL do extrato lipídico. Assim, os resultados obtidos com Aspergillus parasiticus UCP 1182, sugerem como fonte de lipídeos importantes para seu emprego em processos biotecnológico, como aplicação em biocombustíveis e fármacos. / In the last three decades, the search for alternative and renewable fuels had greater evidence on the world stage, due to growing environmental concerns and the prospect of depletion of fossil energy sources. The biomass of microorganisms has been suggested as suitable for conversion to energy. This study aimed to assess the biotechnological potential of Aspergillus spp. isolated from Caatinga through the selection of ten genre samples, Aspergillus niger (3), A. flavus (3), and A. parasiticus (4). Of total lipid extractions were performed and the sample with better percentage held the growth kinetics, characterization of fatty acids and antioxidant activity of selected sample. Samples were grown in synthetic medium Czapek liquid, and reciprocating means (molasses and corn steep liquor sugarcane), using the complete factorial design 23. The total lipids were extracted using binary combination of chloroform and methanol. Total lipid amounts were obtained over 20% in both culture media, featuring the genus Aspergillus as oleaginous. The results indicated that the Aspergillus parasiticus CPU 1132, an output obtained from 2.03 g / L of biomass production and a 44.2% total lipids in Medium Czapek while in alternative production medium (sugar cane molasses and corn steep liquor) obtained in the trial (8) 2,83g biomass to 48.9% of total lipids. The fatty acid profile grown in Czapek medium indicated the presence of acid g [[ raxos linoleic (36.54%) and oleic (33.95%). And alternative way to favor the production of the compound linolenic acid (28.66%) and linoleic acid (40%). In oxidant activity of Aspergillus parasiticus, calculated in linear regression, got the EC50 4.06774 mg / mL of lipid extract. This the results obtained from Aspergillus parasiticus CPU 1182, suggest important as a source of lipids for its use in biotechnological processes such as application and biofuels drugs.

Apesar das vantagens relacionadas ao uso de estruturas de contenção em solo reforçado, a maioria das obras em nosso país ainda é executada por soluções convencionais. A ausência de um conhecimento mais profundo sobre o real comportamento das estruturas em solo reforçado, principalmente em termos de deslocamentos, certamente impede uma utilização mais intensa desse tipo de obra no Brasil. Com isso, para contribuir para um melhor entendimento do desempenho de estruturas em solo reforçado, foram construídos oito protótipos de estrutura de contenção em solo reforçado com geotêxtil, com 4,0 m de altura cada. Todas as estruturas foram instrumentadas, principalmente visando os deslocamentos, para avaliar o comportamento de campo. Adicionalmente, foi realizada a análise, em longo prazo, de um talude íngreme com 15,3 m de altura, construído no estado americano de Idaho, em que foram realizadas leituras até cinco anos após o fim da construção. Esse trabalho apresenta os resultados de cada protótipo construído, juntamente com os resultados do talude íngreme em Idaho, tanto em curto, quanto em longo prazo. As análises desenvolvidas compreendem, além da avaliação dos resultados individuais de cada estrutura, uma análise paramétrica entre todos os protótipos, investigando entre outros fatores, o tipo de solo, tipo de geossintético e geometria interna das estruturas. Além disso, foi realizada uma abordagem especial sobre a análise em longo prazo do protótipo 7. Dentre as conclusões mais importantes obtidas nesta pesquisa, podem-se citar as grandes deformações de fluência registradas no protótipo 7, a tendência de formação de uma superfície potencial de ruptura linear para os protótipos construídos com solo granular e de espiral logarítmica para os protótipos construídos com solos coesivos, a importância da coesão no bom comportamento das estruturas e a redução das movimentações verticais das estruturas com o acréscimo do teor de areia na granulometria do solo / Despite the important advantages associated with the use of geotextiles as reinforcement, most retaining walls in Brazil still use more conventional. The lack of field monitoring data regarding the internal and face displacements of these structures has certainly prevented broader use of this reinforced soil technology. This study addresses several aspects related to the behavior of geotextile-reinforced soil structures, such as the deformability of reinforcement materials under the confinement of soil, and quantification of the actual failure mechanisms. To achieve these goals, eight 4.0 m high geotextile-reinforced soil retaining wall prototypes were built and instrumented in order to quantify their behavior under ambient atmospheric conditions. Granular and poorly draining backfills were used in this study. Innovative construction methods and instrumentation were developed specifically for this research program. A significant laboratory testing program was conducted to quantify the stress-strain properties of the soils and geosynthetics involved in the construction of the walls. As a reference, the behaviors of these prototype structures were compared with that of a long term analysis of a steep slope in Idaho, USA. This wall is 15.3 m high, with displacement measurements carried out until five years after the end of the construction. A parametric analysis was conducted for the prototypes, in order to investigate the effects of soil type, reinforcement type and internal geometry of the structures. Among the most important conclusions obtained in this research, it is the large creep strains observed in prototype 7, the tendency of a linear potential slip surface observed for the walls constructed with granular backfills, and a log spiral slip surface for the prototypes constructed with cohesive backfills, the importance of the apparent cohesion in the behavior of the structures, and the reduction of the vertical movements of the structures with the increase of the amount of sand in the grain size distribution of the soil

Les systèmes sédimentaires turbiditiques présentent un double intérêt académique et industriel puisqu’ils constituent à la fois des archives des conditions environnementales et des réservoirs pétroliers potentiels. Parmi les nombreux paramètres contrôlant l’organisation sédimentaire de ces systèmes l’inclinaison de la pente continentale apparait être un paramètre majeur. L’analyse de l’influence de l’inclinaison de la pente et de ces variations sur l’hydrodynamique des écoulements sédimentaires et ainsi sur l’architecture des systèmes turbiditiques revêt un caractère crucial tant du point de vue académique que pétrolier. Ce travail s’appuie sur l’analyse haute résolution de données acoustiques (bathymétrie, imagerie multifaisceaux, sismique THR, sonar latéral) acquises sur la marge abrupte du Golfe de Gênes (Malisar, Fables, Prisme, Gelo) et de l’analyse d’un bloc de sismique 3D sur la marge abrupte Ivoirienne. Les accumulations turbiditiques des deux sites témoignent de processus de ségrégation des particules avec le piégeage des particules les plus grossières dans des structures en plunge pools, cyclic steps ou slope break deposits. L’étude fine de ces corps liés au ressaut hydraulique apporte ici un éclairage inédit sur la continuité des corps sableux à la transition canyon/lobe et permet ainsi de proposer un nouveau scénario de modèle réservoir. De plus l’analyse de ces deux zones d’études met en évidence l’impact direct de l’activité tectonique sur l’architecture des accumulations turbiditiques par la mise en place et le maintien d’une zone de rupture de pente où le phénomène de ressaut hydraulique peut perdurer au cours du temps. / Turbidite systems present both academic and industrial interests since they are archives of environmental conditions and potential oil reservoirs. Among many parameters controlling the sedimentary organization, the continental slope inclination appears to be a major parameter. The analysis of slope inclination’s and these variations on the hydrodynamic of sedimentary flows and thus on turbidite systems architecture is a crucial character for both academic and industrial interests. The Pliocene-Quaternary turbidite systems of the Gulf of Genoa and upper margin of the Ivorian Cretaceous develop on margins with steep slope profiles controlled by tectonic processes and are suitable and complementary items for the Study of turbidite sedimentation in context of abrupt margin. This work is based on the high-resolution analysis of acoustic data (bathymetry, multibeam imaging, seismic THR, sidescan sonar) acquired on the steep margin of the Gulf of Genova (Malisar, Fables, Prism, Gelo) and the analysis of a 3D seismic block on the Ivorian steep margin. Turbidite accumulations of two sites demonstrate particle segregation processes with trapping coarser particles into specific structures such as plunge pools and cyclic steps. The detailed study of these bodies related to hydraulic jump sheds a new light on the continuity of sand bodies in the transition canyon / lobe and allows the designing of a new reservoir model scenario. Further analysis of these two areas of study shows the direct impact of tectonic activity on the architecture of turbidite accumulations by establishing and maintaining a nick area where the phenomenon of hydraulic jump can be maintained over time.

Orientador: Ranulfo Monte Alegre / Dissertação (mestrado) - Universidade Estsadual de Cam,pinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-18T17:54:10Z (GMT). No. of bitstreams: 1 AlcazarAlay_SylviaCarolina_M.pdf: 2176104 bytes, checksum: 32f8cdfe0b86e00e15edc533c76b33cb (MD5) Previous issue date: 2011 / Resumo: O interesse pela produção de ácido láctico tem crescido fortemente nos últimos anos desde a descoberta das propriedades de seus polímeros, os que apresentam caraterísticas de biodegradabilidade e biocompatibilidade; e sua aplicação como solvente ¿verde¿ ou ambientalmente saudável para os processos de misturas de solventes na indústria química. Dado o potencial econômico do ácido láctico, são necessários processos mais eficazes para sua síntese e redução dos custos de produção. Este trabalho visou aperfeiçoar o processo de produção fermentativa do ácido láctico, determinando formulações do meio de cultura que auxiliarão no desenvolvimento de tecnologias competitivas de produção. Além disso, esse trabalho propõe a utilização de matérias-primas de baixo custo e grande disponibilidade no mercado brasileiro como por exemplo melaço de cana e água de maceração de milho. A espécie selecionada para o estudo foi Lactobacillus delbrueckii, duas linhagens foram estudadas, selecionando-se a que apresentou maior velocidade de crescimento e produção de ácido láctico no meio de cultura padrão. O estudo de otimização da produção de ácido láctico foi realizado utilizando a estratégia de planejamentos experimentais. O uso de melaço de cana e água de maceração de milho como fonte de carbono e nitrogênio, em concentração de 240 gL-1 e 14 gL-1 respectivamente, possibilitou produtividade de até 57,17 gL-1 após 96 horas, com eficiência de 82% (gramas de ácido láctico produzido / grama de substrato utilizado) / Abstract: The interest in lactic acid has grown strongly in the last years since the discovery of its properties of application in production of biodegradable and biocompatible polylactate polymers and their application as "green solvent¿ or ¿safety solvent¿ to processes of mixtures of solvents in the chemical industry. Considering the commercial potential of lactic acid, more efficient processes are needed for its synthesis, reducing costs of production and turning its industrial application more atractive, as its cost still prevents it from being used in some areas. This work aimed at improving the process of fermentative lactic acid production, determining formulations that will help develop competitive technologies of production. Furthermore, the use of low cost raw materials, easily available on the brazilian market, such as sugarcane molasses and corn steep liquor is proposed. The species selected for the study was Lactobacillus delbrueckii, two strains were studied, Lactobacillus delbrueckii spp. bulgaricus, shown the greatest growth speed and lactic acid production in the standard culture medium. The optimization study of lactic acid production was performed using the strategy of experimental design, using sugarcane molasses as a carbon source and corn steep liquor as a nitrogen source allowed a productivity of up to 57,17 gL-1 after 96 hours, with 82% lactic acid yield efficiency (g lactic acid produced / g substrate utilized) using an initial concentration of 240 gL-1 and 14 gL-1 of sugarcane molasses and corn steep liquor respectively / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-07T12:18:46Z No. of bitstreams: 1 catarinamattosbarbosadeoliveira.pdf: 10196740 bytes, checksum: bcd6015af6ac1fe57d36299302b84bbf (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-07T21:40:03Z (GMT) No. of bitstreams: 1 catarinamattosbarbosadeoliveira.pdf: 10196740 bytes, checksum: bcd6015af6ac1fe57d36299302b84bbf (MD5) / Made available in DSpace on 2015-12-07T21:40:03Z (GMT). No. of bitstreams: 1 catarinamattosbarbosadeoliveira.pdf: 10196740 bytes, checksum: bcd6015af6ac1fe57d36299302b84bbf (MD5) Previous issue date: 2015-01-26 / Sabendo-se que grande parte da população mundial vive em áreas geologicamente desfavoráveis e desprovidas de qualquer planejamento, esta dissertação apresenta uma pesquisa cuja temática é atual e de grande relevância no contexto urbano. Tal fato foi e continua sendo determinado pelo crescimento acelerado do processo de urbanização aliado à falta de controle e planejamento adequados ao uso do solo urbano. O objetivo principal deste trabalho é propor alternativas para a gestão das águas pluviais em comunidades de risco, estabelecidas em assentamentos precários, localizadas em áreas com infraestrutura insatisfatória e ambiente degradado, que contribuam para a redução de riscos da comunidade. A metodologia aplicada inicialmente é baseada em uma revisão bibliográfica multidisciplinar, que explora o contexto histórico, a formação, a natureza, as relações, os valores sociais e políticos, os conceitos, os riscos dos desastres naturais. Num segundo momento e tendo como base os conceitos teóricos sobre as soluções técnicas para drenagem superficial das águas pluviais e as condicionantes teóricas que validam essas soluções, foi aplicada uma nova metodologia através da elaboração de uma matriz de decisão adaptada da Metodologia para Desenvolvimento do Produto. Através da seleção de conceitos de produto, o somatório dos valores adotados para as condicionantes da matriz de decisão determinou o produto ou o conjunto de produtos passíveis de serem aplicados na gestão das águas pluviais em encostas acentuadas. Após a identificação das soluções viáveis, foi elaborada uma proposição de intervenção em local específico, tendo como base para a seleção da região, os dados das áreas de grau de risco a deslizamentos determinados pela Subsecretaria de Defesa Civil do município. / Given that much of the world's population lives in geologically unfavorable areas and devoid of any planning, this dissertation presents a research whose theme is current and highly relevant in the urban context. This fact has been and continues to be determined by the rapid growth of urbanization together with the lack of control and planning appropriate to the use of urban land. The main objective of this work is to propose alternatives for the management of stormwater at risk communities, established in slums located in areas with poor infrastructure and degraded environment, contributing to the community risk reduction. The methodology applied is initially based on a multidisciplinary literature review, which explores the historical background, training, nature, relationships, social and political values, concepts, the risks of natural disasters. Secondly, and based on the theoretical concepts of technical solutions for surface drainage of rainwater and the theoretical conditions that validate these solutions was applied a new methodology by developing a tailored decision matrix methodology for product development. By selecting product concepts, the sum of the values adopted for the constraints of decision matrix determined the product or set of products which can be applied in the management of rainwater on steep slopes. After the identification of viable solutions, an intervention proposition in a specific location was drawn up, taking as a basis for selection of the region, the data of risk degree of areas to mudslides determined by the Civil Defence Secretariat of the municipality.

<p>Since the discovery of graphene, two-dimensional (2D) materials have attracted broad interests for transistor applications due to their atomically thin nature. This thesis studies nano-transistors based on 2D materials for several novel applications, including tunneling transistors for low-power electronics and reconfigurable transistors for hardware security.</p><p>The first part of the thesis focuses on tunneling field-effect transistors (TFETs). Since the current injection in a conventional MOSFET depends on thermionic injection over a gate-controlled barrier, the subthreshold swing (SS) of MOSFET is fundamentally limited to 60 mV/dec at room temperature, hindering the supply voltage scaling of integrated circuits (ICs). Utilizing band-to-band tunneling (BTBT) as current injection mechanism, TFETs overcome the SS limit by filtering out the Fermi tail in the source and achieve steep-slope switching. However, existing demonstrations of TFETs are plagued by low on-currents and degraded SS, largely due to the large tunneling distances caused by non-scaled body thicknesses, making 2D materials a promising candidate as channel materials for TFETs. In this thesis, we demonstrate a prototype TFET based on black phosphorus (BP) adopting electrostatic doping that is tuned by multiple top-gates, which allows the device to be reconfigured into multiple operation modes. The band-to-band tunneling mechanism is further confirmed by source-doping-dependent and temperature-dependent measurements, and the performance improvement of BP TFETs with further body and oxide thicknesses scaling is projected by atomistic simulation. In addition, a vertical BP TFET with a large tunneling area is also demonstrated, and negative differential resistance (NDR) is observed in the device.</p><p>The second part of the thesis focuses on reconfigurable nano-transistors with tunable p- and n-type operations and the implementation of hardware security based on such transistors. Polymorphic gate has been proposed as a hardware security primitive to protect the intellectual property of ICs from reverse engineering, and its operation requires transistors that can be reconfigured between p-type and n-type. However, a traditional CMOS transistor relies on substitutional doping, and thus its polarity cannot be altered after the fabrication. By contrast, 2D nano-transistors can attain both electron and hole injections. In this thesis, we review the Schottky-barrier injection in 2D transistors and demonstrate the feasibility of achieving complementary p-type and n-type transistors using BP as channel material by adopting metal contacts with different work functions. In this design, however, the discrepancy in the p-FET and n-FET device structures makes it unsuitable for reconfigurable transistors. Therefore, we continue to modify the device design to enable reconfigurable p-type and n-type operations in the same BP transistor. Finally, a NAND/NOR polymorphic gate is experimentally demonstrated based on the reconfigurable BP transistors, showing the feasibility of using 2D materials to enable hardware security.</p><p>In the last part, we demonstrate an artificial sub-60 mV/dec switching in a metal-insulator-metal-insulator-semiconductor (MIMIS) transistor. Negative capacitance FETs (NC-FETs) have attracted wide interest as promising candidates for steep-slope devices. However, the detailed mechanisms of the observed steep-slope switching are under intense debate. We show that sub-60 mV/dec switching can be observed in a WS2 transistor with an MIMIS structure – without any ferroelectric component. Using a resistor-capacitor (RC) network model, we show that the observed steep-slope switching can be attributed to the internal gate voltage response to the chosen varying gate voltage scan rates. Our results indicate that the measurement-related artefacts can lead to observation of sub-60 mV/dec switching and that experimentalists need to critically assess their measurement setups.</p>

O objetivo desta dissertação foi estudar dispositivos para contenção de veículos desgovernados por falta de freios em declives longos e íngremes. Para tanto, fez-se uma revisão abrangente da literatura especializada e coletaram-se dados em testes realizados na área de escape construída no km 42,7 da pista sul da Via Anchieta, onde existe um declive de 12,8 km de extensão. A pesquisa relatada nesta dissertação focaliza três aspectos principais: a eficiência do dispositivo em deter caminhões sem freios, a localização do dispositivos e a determinação da velocidade segura de operação de caminhões nesse declive. Dados empíricos da desaceleração dos caminhões no dispositivo foram coletados com auxílio de GPS, o que permitiu estudar o comportamento dos caminhões dentro da caixa de retenção. Os dados coletados foram usados para a calibração de um modelo capaz de estimar a desaceleração média proporcionada pelo dispositivo em função da velocidade de entrada e do número de eixos do caminhão. Para a análise da localização do dispositivo, propôs-se um modelo que leva em consideração o perfil vertical do declive, a velocidade dos caminhões, a temperatura dos freios e a frequência de acidentes com veículos desgovernados ao longo do declive. A determinação da estratégia ótima de condução no declive consistiu em determinar a máxima velocidade que os caminhões podem percorrer o declive sem que os freios sofram superaquecimento. Os parâmetros usados na análise foram a massa bruta total do veículo e as reduções da sua caixa de câmbio. Foram estabelecidas velocidades e marchas máximas para 16 tipos de caminhão. Os resultados obtidos mostram que este tipo de dispositivo é capaz de deter caminhões desgovernados com segurança e podem subsidiar projetos de novas áreas de escape no Brasil. / The objective of the dissertation was to study devices for arresting runaway trucks on long and steep downgrades. A comprehensive review of the literature was carried out and empirical data were collected by means of real life trials at an arrester bed build at a 12.8 km downgrade on the southward lanes of Via Anchieta, the old highway connecting the cities of São Paulo and Santos, in Brazil. The research reported focused on three major aspects: arresting capability of the escape area, location of the escape area and safe operating speeds for trucks on this downgrade. Truck deceleration data were collected during the trials by means of GPS equipment installed in the vehicles and were used to determine truck behavior within the arrester bed. A mathematical model, which allows the estimation of average deceleration as a function of entry speed and number of axles, was fitted to the observed data. The location study proposed a method to establish the points along the downgrade where arrester beds are needed, based on road profile, truck speed, brake temperature and accident data. Optimal driving strategies for truck drivers to negotiate safely the downgrade were also studied, in order to determine the downgrade maximum speed that would avoid brake overheating. The parameters used in this analysis were gross vehicle mass and gearbox characteristics. Safe maximum downgrade speeds and gears were established for 16 truck models. The results, which showed that arrester beds are capable of safely stopping runaway trucks in long and steep downgrades, may also be used to assist the design of new arrester beds in Brazil.

Made available in DSpace on 2017-07-21T18:53:13Z (GMT). No. of bitstreams: 1 EDENES MARIA SCHROLL LOSS.pdf: 3283056 bytes, checksum: b462cc2219aab59d022c471e4469c9f0 (MD5) Previous issue date: 2009-05-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The agroindustrialization of corn base products through humid processing results in solid and liquid by-products, which disposed in inadequate form become sources of contamination and aggression to the environment. The present work had as its objective the valorization and use of these by-products of the corn chain (straw of corncob, corn steep licor and corncob), using the solid state fermentation (SSF) for the production of Pleurotus spp mushrooms, a product with important nutritional, functional and gastronomical characteristics. The first stage of this work comprised the characterization of the selected by-products (straw of corncob, corncob and corn steep licor), which were the base to the studies of composed-base obtaining with potential for the production of Pleurotus (ostreatus and florida). In the second stage a 23 factorial planning indicated that corncob straw + corn steep licor and water 1:1 in pH = 5,0 presented better biological efficiency for both species of Pleurotus (florida and ostrearus). Kinetic studies accomplished with the composed-base that presented better efficiency revealed a significant interaction between the variable crude fiber and C/N relation, indicating that these factors are important for the mushroom development process. The characterization of the fruiting bodies of the produced mushrooms indicated nutritional values equivalent to the ones in the literature, since it was obtained 92,18% of humidity, 13,50% of proteins, 1,00% of lipids, 65,76% of total carbohydrates, 4,56% of ashes, and energy value of 25,48 Kcal/100g. Quantitative analyses of the aflatoxin and zearalenona mycotoxins indicated inferior values to the limits set by the national and international legislations for corn grains. The presence of these pollutants indicates that they were absorbed from the substract by the fungus. / A agroindustrializa??o de produtos a base de milho atrav?s de processamento ?mido resulta em subprodutos s?lidos e l?quidos, que dispostos de forma inadequada tornam-se fontes de contamina??o e agress?o ao meio ambiente. O presente trabalho teve como objetivo a valoriza??o e o aproveitamento destes subprodutos da cadeia do milho (palha do sabugo do milho, milhocina e sabugo do milho), utilizando a fermenta??o no estado s?lido (FES) para a produ??o de cogumelos Pleurotus spp, produto com importantes caracter?sticas nutricionais, funcionais e gastron?micas. A primeira etapa do trabalho se resumiu na caracteriza??o dos subprodutos selecionados (palha do sabugo de milho, sabugo de milho e milhocina), que foram base para os estudos de obten??o de composto-base com potencial para a produ??o de Pleurotus (ostreatus e florida). Na segunda etapa um planejamento fatorial 23 indicou que palha do sabugo do milho + milhocina e ?gua 1:1 em pH = 5,0 apresentou melhor efici?ncia biol?gica para ambas as esp?cies de Pleurotus (florida e ostreatus). Estudos cin?ticos realizados com o composto-base que apresentou melhor efici?ncia revelaram uma significativa intera??o entre a vari?vel fibra bruta e rela??o C/N, indicando serem estes fatores importantes para o processo de desenvolvimento dos fungos. A caracteriza??o dos corpos de frutifica??o dos cogumelos produzidos indicou valores nutricionais equivalentes aos da literatura, tendo sido obtidos em base seca: 92,18% de umidade, 13,50% de prote?nas, 1,00% de lip?deos, 65,76 de carboidratos totais, 4,56% de cinzas e valor energ?tico de 25,48 Kcal/100g. An?lises quantitativas das micotoxinas aflatoxina e zearalenona indicaram valores inferiores aos limites estipulados pelas legisla??es nacionais e internacionais, para gr?os de milho. A presen?a desses contaminantes indica que estes podem ter sido absorvidos dosubstrato pelo fungo.