Hidrologia subsuperficial e propriedades físico-mecânicas dos complexos de rampa - Bananal (SP)

Resum

Desenvolvimento de um chassi para utilização em veículos de baixo custo

A presente dissertação que pretende contribuir para projetos bem-sucedidos na área de veículos de baixo custo, tem como objetivo principal projetar, analisar e conceber uma estrutura tubular que funcione como chassi e suporte dos principais componentes de um automóvel inserido na categoria de quadriciclo pesado. Esta categoria obriga a uma segurança ativa e passiva enquadrada no transporte de dois ou quatro passageiros a uma velocidade autorizada em vias limitadas, sendo necessário que a estrutura disponha de uma rigidez compatível com os padrões de segurança para tais vias e velocidades de circulação. A preocupação ambiente, a finitude do petróleo, o custo de vida e a procura por novas soluções impulsionaram a procura de soluções de mais baixo custo. Esta tese corrobora a ideia, após pesquisa e estudo alargado, de que a utilização de chassis tubulares de perfil múltiplo são uma solução fiável, sobretudo quando se procuram custos de fabrico, mão de obra e de produção reduzidos. Foi inicialmente proposto um chassi totalmente tubular, sobre o qual se procurou efetuar o máximo possível de testes, que envolvessem a submissão da estrutura a cargas de flexão, de torção, assim como a vários impactos. Por forma a serem cumpridos os objetivos estabelecidos: custo, sustentabilidade / ecologia e segurança, determinou-se que a melhor solução, seria a introdução do veículo na categoria de quadriciclo pesado, dada a facilidade com que seria possível cumprir estes mesmos objetivos. Para tal foi necessário pesquisar toda a legislação referente a esta categoria de veículos, vindo a ser determinado um conjunto de incoerências no chassi inicialmente proposto. A implicação anterior associada ao conhecimento adquirido com os testes efetuados permitiu que fosse realizada uma nova proposta para o chassi, todavia não totalmente constituída por perfis circulares. O recurso atempado ao software de simulação veio demonstrar claras vantagens sobre o cálculo manual, ao nível do tempo e da viabilidade dos resultados, ainda assim efetua-se a demonstração do processo de cálculo. Deste modo os resultados apresentados neste documento, apenas se referem aqueles obtidos com recurso ao software Abaqus.This thesis aims to contribute for succeeded frame designs in the field of low cost small utility vehicles. The frame is a vehicle subset having a role of primary importance, not only with the capability of fixing additional elements that are essential for a safe and comfortable run (as the engine, suspension elements, passenger seat and driving instruments) and, not less important, ensuring the highest passive safety for the category of the vehicle in discussion. The environment preservation concerns allied with the predictable oil shortage in a relatively close future push the development of environment friendly vehicles via lightweight, low cost and small size designs, so contributing in a first approach of the subject for effective projects in the more agreeable urban mobility and preservation of a health and sustainable environment. The vehicle frame was designed with advanced commercial software (as Abaqus) so that a high rank of accuracy and design for safety and reliability could be achieved. Analytical calculations, though didactic and promoting a good insight for a former approach to estimate design dimensions, is quite time consuming for the high number of unknows the problem should deal with. Automatic computational tasks revealed the right choice for successive iterations of the calculation assigned to each component in order to achieve the ideal stiffness / mass ratio.Mestrado em Engenharia Mecânic

The effect of habitat reduction by roads on space use and movement patterns of an endangered species, the Cabrera vole Microtus cabrerae

Roads are among the most widespread signs of man’s presence around the globe. From simple low traffic trails to wide and highly used highways, roads have a wide array of effects on wildlife. In the present study, we tested how habitat reduction by roads may affect the space use and movement patterns of the Cabrera vole (Microtus cabrerae), a near-threatened Iberian endemism, often living on road verges. A total of 16 voles were successfully radio-tracked in two habitat patches with different size and proximity to roads. Results showed that individuals from the smaller patch (Verge patch) had smaller and less complex home-ranges than those from the larger patch (Meadow patch). Movement patterns were significantly influenced by the day period but only in individuals from the Verge patch. There was evidence of a barrier effect in both habitat patches, being this effect much more noticeable in the verge population. Overall, this study shows that space use and movement patterns of Cabrera voles near roads may be affected by the degree of habitat reduction imposed by these infrastructures. This suggests that species space use and movement patterns at fine-scale should be accounted for in road planning, even for species that may benefit from road verge habitats as refuges.Comissão Europeia., Programa LIFE. Projeto LIFE LINES (LIFE14 NAT/PT/001081

First and second fundamental solutions of the time-fractional telegraph equation of order 2α

In this work we obtain the first and second fundamental solutions of the multidimensional time-fractional equation of order $2\alpha$, $\alpha \in ]0,1]$, where the two time-fractional derivatives are in the Caputo sense. We obtain representations of the fundamental solutions in terms of Hankel transform, double Mellin-Barnes integral, and H-functions of two variables. As an application, the fundamental solutions are used to solve a Cauchy problem, and to study telegraph process with Brownian time.publishe

A 5G-based authentication framework for V2X communication

The integration of Vehicle-to-everything (V2X) communication and Intelligent Transportation Systems (ITS) promises to revolutionize smart mobility. However, this technological advancement also exposes V2X networks to cybersecurity threats. To address these challenges, this work explores the critical security requirements for V2X communications, including User Equipment (UE) authorization, data integrity protection, and privacy support

Damage localization on CFRP composites by electrical impedance tomography

This work exploited the use of electrical impedance tomography (EIT) with one-step difference Gaussian-Newton (GN) algorithm to detect different types of damage on unidirectional carbon fibre/epoxy composite laminates. The major challenge concerning the implementation of EIT on composite materials has to do with their anisotropy. To assess this issue, this study was conducted on carbon fibre composites having different layup configurations with different degrees of anisotropy: a quasi-isotropic layup, to approximate as much as possible these layered materials to an isotropic material, and an unbalanced layup, with further degree of anisotropy. Damage detection in the highly anisotropic unbalanced laminates is a major challenge for EIT technique, which has not been assessed before in the literature. Severe damage, in the form of through-thickness holes, was created in the laminates with different diameters and at two locations of the specimen to evaluate the sensitivity of this technique to damage size and its capacity to detect multiple damages. EIT showed progressive decrease of electrical conductivity as the diameter of through-thickness holes increased. Impact damages of different severities were also created. The EIT technique was able to distinguish different damage shapes in the laminates with different anisotropy. EIT identified elongated shaped damages, produced by impact events of different impact energies, on unbalanced laminates. However, the EIT images overestimate the damaged area, as compared to non-destructive ultrasonic inspections. The EIT images of the quasi-isotropic laminates revealed damage in the central area of the specimens, but a well-defined damage shape could not be distinguished.ANI, H2020, Contrato NORTE-01-0145-FEDER-00001

Electrical impedance tomography for damage detection and localization on carbon fibre reinforced polymer composites

Electrical impedance tomography (EIT) is being developed as promising non-intrusive technology for damage detection in conductive fibre reinforced polymers (FRP) composites. This work assessed EIT and one-step difference Gaussian-Newton algorithm to detect different damages in CFRP laminates, including through-thickness holes and impact damage of different severities. Two layup laminates were studied: quasi-isotropic [0/45/90/-45]s and unbalanced [0/0/45/90/-45]s. Each laminate configuration was subjected to three levels of impact energy.Through-thickness holes with diameters as small as 2 mm were detected. The LVI on unbalanced specimens created elongated shaped damages, which were observed through EIT and ultrasonic C-scan. Differently, the ultrasonic C-scan inspections revealed circular shaped damages on the centre of the quasi-isotropic specimens, while EIT could not reveal a well-defined damage shape Yet, the presence of damage was observed in the centre of the specimens by EIT. Although EIT overestimated the damaged area, it was highly sensitive to the imposed damages.The authors would like to acknowledge the support of the European Regional Development Fund [grant number NORTE-01-0145-FEDER-000015]; and of the European Space Agency [Network/Partnering Initiative Program - ESA Contract 4000123315]

Fundamentação téorica do modelo matemático para previsão de escorregamentos rasos Shallow Stability

Em áreas tropicais, escorregamentos são fenômenos comuns principalmente durante fortes chuvas que acontecem freqüentemente no verão. No Brasil, vários escorregamentos catastróficos vêm acontecendo em diversas regiões, principalmente nas três últimas décadas, devido à ocupação humana em escarpas íngremes. Com intuito de prever as porções da paisagem susceptíveis a ocorrência desses fenômenos, o modelo SHALSTAB (Shallow Stability) foi desenvolvido combinando um modelo hidrológico com um modelo de estabilidade de encosta, a partir de modelos digitais de terreno.Isto permite determinar a razão entre a quantidade de chuva e a transmissividade necessária para desestabilização da encosta, baseada na área de contribuição,declividade, ângulo de atrito, densidade e coesão do solo. Dentro deste contexto este trabalho tem como objetivo descrever esta metodologia demonstrando os fundamentos utilizados para o desenvolvimento do modelo de predição. _________________________________________________________________________________ ABSTRACTIn tropical areas, landslides are common phenomena especially durin gstrong rainfall that took place frequently in the summer. In Brazil, many catastrophic and slides occurred in many regions, mainly in the three last decades, due to humano ccupation in steep slope areas. In order to predict the landscape portions susceptibleto occurrence of these phenomena the SHALSTAB model was developed combininga hydrological model with the infinite slope stability model from digital elevation model. This allow to calculate the ratio of the steady state rainfall to soil transmissivityneeded to trigger slope failure based on drainage area, local slope, bulk density, frictionangle and soil cohesion. Thus, the present work has aim to describe SHALSTAB showing the fundaments used to develop the predict model

Predicting Microhabitat Suitability for an Endangered Small Mammal Using Sentinel-2 Data

Accurate mapping is a main challenge for endangered small-sized terrestrial species. Freely available spatio-temporal data at high resolution from multispectral satellite offer excellent opportunities for improving predictive distribution models of such species based on fine-scale habitat features, thus making it easier to achieve comprehensive biodiversity conservation goals. However, there are still few examples showing the utility of remote-sensing-based products in mapping microhabitat suitability for small species of conservation concern. Here, we address this issue using Sentinel-2 sensor-derived habitat variables, used in combination with more commonly used explanatory variables (e.g., topography), to predict the distribution of the endangered Cabrera vole (Microtus cabrerae) in agrosilvopastorial systems. Based on vole surveys conducted in two different seasons over a ~176,000 ha landscape in Southern Portugal, we assessed the significance of each predictor in explaining Cabrera vole occurrence using the Boruta algorithm, a novel Random forest variant for dealing with high dimensionality of explanatory variables. Overall, results showed a strong contribution of Sentinel-2-derived variables for predicting microhabitat suitability of Cabrera voles. In particular, we found that photosynthetic activity (NDI45), specific spectral signal (SWIR1), and landscape heterogeneity (Rao’s Q) were good proxies of Cabrera voles’ microhabitat, mostly during temporally greener and wetter conditions. In addition to remote-sensing-based variables, the presence of road verges was also an important driver of voles’ distribution, highlighting their potential role as refuges and/or corridors. Overall, our study supports the use of remote-sensing data to predict microhabitat suitability for endangered small-sized species in marginal areas that potentially hold most of the biodiversity found in human-dominated landscapes. We believe our approach can be widely applied to other species, for which detailed habitat mapping over large spatial extents is difficult to obtain using traditional descriptors. This would certainly contribute to improving conservation planning, thereby contributing to global conservation efforts in landscapes that are managed for multiple purposes

Condicionantes geomorfológicos dos deslizamentos nas encostas : avaliação de metodologias e aplicação de modelo de previsão de áreas susceptíveis

Deslizamentos são episódios de extrema importância, resultantes da atuação de processos geomorfológicos nas mais diversas escalas temporais causando, em geral, enormes prejuízos à sociedade. Dentre os diversos fatores condicionantes destacam-se os parâmetros morfológicos do terreno, os quais controlam diretamente o equilíbrio das forças e, indiretamente, a dinâmica hidrológica dos solos. Embora muitos estudos tenham voltado a atenção para a descrição de eventos e para o monitoramento de campo, pouco ainda se sabe sobre a previsão de ocorrência destes fenômenos. Acredita-se aqui que a combinação de mapeamentos e monitoramentos de campo, através de modelos matemáticos baseados em processos, tenha muito a contribuir nessa direção. Neste sentido, diversos estudos de campo vêm sendo realizados nas bacias dos rios Quitite e Papagaio no sentido de caracterizar o papel desempenhado pelos diversos parâmetros topográficos no condicionamento dos deslizamentos ali ocorridos em 1996. A partir do modelo digital de terreno das bacias, com uma resolução de 4m2, combinado com vários mapeamentos ali realizados, foi definido o potencial de deslizamento para as diversas classes de cada atributo topográfico. Paralelamente, foram realizados ensaios de campo com o permeâmetro de Guelph e simulações com o modelo matemático SHALSTAB, voltado para a previsão de áreas instáveis, de modo a englobar os mais diferentes cenários. Os resultados atestam o importante papel desempenhado pelos parâmetros topográficos forma da encosta e área de contribuição, geralmente desprezados pelas metodologias de previsão de áreas susceptíveis a deslizamentos. ______________________________________________________________________________ ABSTRACTLandslides are important geomorphological processes, acting along different temporal scales and generally causing huge problems to society. Between the different controlling factors an important role is played by the morphological parameters which directly affect the equilibrium between the forces and indirectly control hillslope hydrology. Although many studies have focused on the description of previous events and field monitoring, little is known about landslide prediction, defining where and when these processes will happen in the near future. It is believed that the combination of field mapping and monitoring with process-based mathematical models is an important tool to landslide investigation. A variety of studies have been carried out in Quitite and Papagaio river basins in order to investigate the role played by the topographic parameters in the landslides triggered by 1996 intense rainstorms. Based on the digital terrain model of the basins, with a 4m2 resolution, together with the different maps obtained, a landslide potential index for the many classes of each topographic attribute was defined. At the same time, field experiments with the Guelph permeameter were carried out and a variety of scenarios were simulated with the SHALSTAB model, a mathematical model for the topographic control on shallow landslides. The results attest the important role played by the topographic parameters hillslope form and contribution area on landsliding in the studied area. However, these topographic attributes are not considered by most of the procedures used to predict landslide generatio