Orientador: Fernando Galembeck / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T15:23:30Z (GMT). No. of bitstreams: 1 Gouveia_RubiaFigueredo_M.pdf: 1322724 bytes, checksum: 354ae5145ed6ce8d69bae986b50bda01 (MD5) Previous issue date: 2005 / Resumo: Atualmente muitas tecnologias importantes são baseadas nos princípios eletrostáticos, como por exemplo, a pintura eletrostática, a reciclagem de termoplásticos e a eletrofotografia. No entanto, mesmo considerando todo o desenvolvimento da eletrostática, ainda existem muitas questões importantes não respondidas, quando se considera a eletrização de materiais isolantes. Na maioria dos casos não se conhece quais são as espécies portadoras de cargas, nem como elas podem ser detectadas e identificadas. Trabalhos anteriores deste laboratório mostraram que os portadores de cargas em látexes são íons simples (K, RSO4, etc). Neste trabalho foram estudados os padrões eletrostáticos criados em uma superfície de sílica, recoberta por um conjunto de eletrodos interdigitados de ouro. As amostras foram preparadas utilizando técnicas microlitográficas e sua superfície foi investigada usando as microscopias de força atômica (AFM) e de varredura de potencial elétrico (SEPM). Foram obtidos padrões eletrostáticos reprodutíveis; a aplicação de uma diferença de potencial elétrico entre os eletrodos produz padrões de potenciais elétricos que desaparecem rapidamente quando os eletrodos são curto-circuitados e aterrados. O tempo de relaxação desses padrões foi de aproximadamente 10 minutos sob umidade de 70% e eles são fortemente influenciados pela umidade relativa da atmosfera, apresentando um tempo de decaimento superior a 1 hora, quando a superfície é exposta a uma umidade relativa de 10%. Os resultados são interpretados usando um modelo simples baseado na quimisorção de espécies presentes na atmosfera acompanhada de reações eletródicas, podendo ser aplicado a outros isolantes. / Abstract: Many current important technologies are based on electrostatic principles, as for instance electrostatic painting, polymer recycling and photocopying. However, even considering its long history, there are still many open questions in the study of electric phenomena in insulators. For instance, how can charge carriers in insulators be detected, identified and quantified? In this laboratory the examination of latexes showed that the charge carriers are K e RSO4 ions. This work describes reproducible electric potential patterns created on silica surfaces, covered with sets of interdigitated parallel gold electrodes by using microlithography techniques. The patterns are detected by concurrent atomic force microscopy (AFM) and scanning electric potential microscopy (SEPM). The images were acquired while electrodes were biased and also after they were all short-circuited and grounded, producing reproducible electrostatic patterns. Characteristic times for pattern formation and relaxation are in the order of 10 minutes at 70% relative humidity and they are strongly influenced by the relative humidity of the atmosphere, showing a relaxation time in the order of 1 hour, when the surface is under 10% RH. The results are interpreted using a model based on the chemisorption of atmospheric water and electrochemical activity at the silica surface. The sum up, this work describes a new approach to the study of the electrification of insulator surfaces that produces reproducible results and can be applied to many other cases. / Mestrado / Físico-Química / Mestre em Química

Successful management of an invasive species requires in depth knowledge of the invader, the invaded ecosystem, and their interactions. The complexity of the species-system interactions can be reduced and represented in ecological models for better comprehension. In this study, a spatially explicit population model was created using the RAMAS software package to simulate the past and future invasion dynamics of the eastern grey squirrel (Sciurus carolinensis) in the fragmented habitat in case study areas in Ireland. This invasive squirrel species causes economic damage by bark stripping forest crops and is associated with the decline of its native congener (S. vulgaris). Three combinations of demographic and dispersal parameters, which best matched the distribution of the species shortly after introduction, were used to simulate invasion dynamics. Future population expansion was modeled under scenarios of no control and two different management strategies: fatal culls and immunocontraceptive vaccination programmes. In the absence of control, the grey squirrel range is predicted to expand to the south and southwest of Ireland endangering internationally important habitats, vulnerable forest crops, and the native red squirrel. The model revealed that region-wide intensive and coordinated culls would have the greatest impact on grey squirrel populations. Control strategies consisting solely of immunocontraceptive vaccines, often preferred by public interest groups, are predicted to be less effective. Complete eradication of the grey squirrel from Ireland is not economically feasible and strategic evidence-based management is required to limit further range expansion. Ecological models can be used to choose between informed management strategies based on predicted outcomes.

This volume comprises ninety-one contributions to the Sediment 2011 conference of the Central European section of the Society for Sedimentary Geology (SEPM-CES) and the Geologische Vereinigung (GV) at the University of Leipzig held in June 2011. The central theme of this meeting was “Sediments: Archives of the Earth System” in order to bring together young and established researchers from all fields of soft-rock geology and beyond to shape a stimulating interdisciplinary program on the role of sediments in understanding the System Earth and the evolution of paleoenvironments and climate through time.

This volume comprises ninety-one contributions to the Sediment 2011 conference of the Central European section of the Society for Sedimentary Geology (SEPM-CES) and the Geologische Vereinigung (GV) at the University of Leipzig held in June 2011. The central theme of this meeting was “Sediments: Archives of the Earth System” in order to bring together young and established researchers from all fields of soft-rock geology and beyond to shape a stimulating interdisciplinary program on the role of sediments in understanding the System Earth and the evolution of paleoenvironments and climate through time.

Consideration of forest management at the landscape scale is essential if commitments to the conservation of biodiversity are to be upheld. The ecosystem management approach, developed largely in North America, has made use of various landscape modelling tools to assist in planning for biodiversity maintenance and ecological restoration. The roles of habitat suitability models, metapopulation models, spatially explicit population models (SEPMs) and forest landscape dynamics models (FLDMs) in the planning process are discussed and a review of forest dynamics models is presented. Potential is identified for developing landscape models in the UK for both landscape restoration projects and semi-natural woodland management. Glen Affric, in northern Scotland contains a large area of native pine and birch woodland and is the subject of a long-term restoration project. A new model, GALDR (Glen Affric Landscape Dynamics Reconstruction) is introduced and is believed to be the first FLDM developed for British woodland. The theory behind the model is described in detail and preliminary results and sensitivity analyses are presented. Furthermore, GALAM (Glen Affric Lichen Abundance Model), a new SEPM for the rare epiphytic lichen Bryoria furcellata is also described. Results of simulations from the linked GALDR and GALAM models are presented which shed light on the role of landscape heterogeneity in determining the dynamics of lichen habitats and populations. It is concluded that, whilst much work will be required to develop a management-oriented decision support system from the GALDR model, the modelling process may aid researchers in the identification of knowledge gaps in ecological theory relevant to management and restoration.