Snake-3D na Modelagem Tridimensional e Medição do Comprimento de Arcos Elétricos

Nesse trabalho é descrita a aplicação inédita de um contorno ativo tridimensional (snake-3D) na avaliação do comprimento de arcos elétricos artificialmente gerados em torres de alta tensão e capturados através um par de câmeras calibradas. Asnake-3D é representada espacialmente por uma B-spline que evolui sob as restrições de forças externas ao contorno ativo e internas a este. As forças externas são obtidas a partir dos pares de imagens que capturam a evolução do arco elétrico, enquanto que as forças internas são intrínsecas ao contorno ativo e determinadas pela tensão entre pontos de controle adjacentes. Em relação às outras abordagens para recuperaçãoda geometria 3D de arcos elétricos, o modelo aqui proposto é independente da determinação de pontos homólogos e de um posicionamento específico de câmeras além de propiciar o rastreio do arco elétrico levando em consideração a dependênciatemporal entre pares consecutivos de quadros em dois vídeos. Para fins de avaliação foram realizados experimentos sobre imagens sintéticas obtidas a partir da simulação de um sistema de aquisição de imagens, bem como experimentos com imagens de arcos elétricos reais produzidos no CEPEL. Os resultados obtidos foram considerados aceitáveis, demonstrando o potencial da abordagem apresentada

Venom Yield, Regeneration, and Composition in the Centipede Scolopendra Polymorpha

In this dissertation, I investigated yield, regeneration, and composition of centipede venom. In the first of three empirical studies, I investigated how size influenced venom volume yield and protein concentration in Scolopendra polymorpha and S. subspinipes. I also examined additional potential influences on yield in S. polymorpha, including relative forcipule size, relative mass, geographic origin, sex, time in captivity, and milking history. Volume yield was positively linearly related to body length in both species; however, body length and protein concentration were uncorrelated. In S. polymorpha, yield was most influenced by body length, but was also positively associated with relative forcipule length and relative body mass. In the second study, I investigated venom volume and total protein regeneration during the 14-day period subsequent to venom extraction in S. polymorpha. I further tested the hypothesis that venom protein components, separated by RP-FPLC, undergo asynchronous synthesis. During the first 48 hours, volume and protein mass increased linearly. However, protein regeneration lagged behind volume regeneration, with only 65–86% of venom volume and 29–47% of protein mass regenerated during the first 2 days. No significant additional regeneration occurred over the subsequent 12 days. Analysis of chromatograms of individual venom samples revealed that five of 10 chromatographic regions and 12 of 28 peaks demonstrated changes in percent of total peak area among milking intervals, indicating that venom proteins are regenerated asynchronously. In the third study, I characterized the venom composition of S. polymorpha using proteomic methods. I demonstrated that the venom of S. polymorpha is complex, generating 23 bands by SDS-PAGE and 56 peaks by RP-FPLC. MALDI TOF MS revealed hundreds of components with masses ranging from 1014.5 to 82863.9 Da. The distribution of molecular masses was skewed toward smaller peptides and proteins, with 72% of components found below 12 kDa. BLASTp sequence similarity searching of MS/MSderived amino acid sequences demonstrated 20 different sequences with similarity to known venom components, including serine proteases, ion-channel activators/inhibitors, and neurotoxins. In Appendix A, I reviewed how animals strategically deploy various emissions, including venom, highlighting how the metabolic and ecological value of these emissions leads to their judicious use

The initiation of electric arcs and the possible impact in industrial environments

Advancing knowledge and understanding of electrical arc flash and arc blast hazards through experimentation, modelling and analysis is the main goal of the present thesis. To achieve this, initially, significant work has been carried out to analyse existing data on arc flash hazards and mitigation engineering practices in industrial premises. Then, experimental investigations on the electrical arc characteristics have been conducted which together with the development of an analytical model for quantification of arc's energy components have formed the core of the research project.;Electrical characteristics of the initial stage of the arc have been obtained experimentally using different test systems developed in the course of this study. Two different arc initiation mechanisms have been examined: self-breakdown spark gap (SBSG) and wire-guided spark gap (WGSG) discharge initiation. Data post-processing techniques have been developed to obtain arc voltage and current waveforms for calculating the electrical arc energy available in the discharge.;An analytical model has been developed based on the hydrodynamic approach, to further analyse the energy dissipated and to obtain the energy components associated with thermal, acoustic-kinetic and light emission processes. This analysis of the energy components provides data for safety considerations which are currently not taken into account by the existing standards. Furthermore, analysis and evaluation of the suitability of black-box models for predicting the arc characteristics during its initiation taking into account electric circuit parameters have been performed.;Initial conditions for analysis of the ratio of the arc current over voltage have been obtained from experimental waveforms to investigate the arc-electrical circuit interaction. This can be considered as a first step towards establishment of a complete accurate link between the microscale and macroscale manifestation of the arc flash and arc blast phenomena. It is envisaged that further understanding of the complex energy conversion processes taking place in the post-arc-initiation process can provide additional tools for quantifying arc energy components and improving arc flash and arc blast safety.Advancing knowledge and understanding of electrical arc flash and arc blast hazards through experimentation, modelling and analysis is the main goal of the present thesis. To achieve this, initially, significant work has been carried out to analyse existing data on arc flash hazards and mitigation engineering practices in industrial premises. Then, experimental investigations on the electrical arc characteristics have been conducted which together with the development of an analytical model for quantification of arc's energy components have formed the core of the research project.;Electrical characteristics of the initial stage of the arc have been obtained experimentally using different test systems developed in the course of this study. Two different arc initiation mechanisms have been examined: self-breakdown spark gap (SBSG) and wire-guided spark gap (WGSG) discharge initiation. Data post-processing techniques have been developed to obtain arc voltage and current waveforms for calculating the electrical arc energy available in the discharge.;An analytical model has been developed based on the hydrodynamic approach, to further analyse the energy dissipated and to obtain the energy components associated with thermal, acoustic-kinetic and light emission processes. This analysis of the energy components provides data for safety considerations which are currently not taken into account by the existing standards. Furthermore, analysis and evaluation of the suitability of black-box models for predicting the arc characteristics during its initiation taking into account electric circuit parameters have been performed.;Initial conditions for analysis of the ratio of the arc current over voltage have been obtained from experimental waveforms to investigate the arc-electrical circuit interaction. This can be considered as a first step towards establishment of a complete accurate link between the microscale and macroscale manifestation of the arc flash and arc blast phenomena. It is envisaged that further understanding of the complex energy conversion processes taking place in the post-arc-initiation process can provide additional tools for quantifying arc energy components and improving arc flash and arc blast safety

RSME 2011. Transfer and Industrial Mathematics. Proceedings of the RSME Conference on Transfer and Industrial Mathematics. Santiago de Compostela, July 12-14, 2011

[EN] The RSME Conference on Transfer and Industrial Mathematics is supported by the Royal Spanish Mathematical Society, a scientific society for the promotion of mathematics and its applications as well as the encouragement of research and teaching at all educational levels. The three-day conference presents successful experiences in the field of mathematical knowledge transfer to industry and focuses on the following issues: — Showing how collaboration with industry has opened up new lines of research in the field of mathematics providing high quality contributions to international journals and encouraging the development of doctoral theses. — How the promotion of existing infrastructures has contributed to enhance the transfer of mathematical knowledge to industry. — The presentation of postgraduate programs offering training in mathematics with industrial applications. The conference includes talks from researchers and industry representatives who present their different points of view and experiences with regards to the transfer of mathematical knowledge to industry

3D modeling for determination of lenght of electrical arcs using stereo images

Orientador: Maria Cristina Dias TavaresTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: O comprimento do arco elétrico é um parâmetro importante para a modelagem matem ática do arco elétrico. O perfil da variação do comprimento do arco atualmente é estimado pela análise da tensão medida entre os terminais do arco e da corrente do arco. Porém esses resultados não são conclusivos, pois não apresentam uma medição (escala métrica) do eixo-médio tridimensional do arco elétrico. Por outro lado, as imagens da evolução do arco podem fornecer informação suficiente à reconstrução do seu eixo tridimensional e à estimativa do comprimento do arco a cada instante, determinando uma curva de variação do comprimento. A principal contribuição deste trabalho, portanto, reside na obtenção da estimativa do comprimento do arco e, por conseguinte, do alongamento de arcos elétricos baseada na aplicação do modelo snake-3D na reconstrução tridimensional dos eixos longitudinais de arcos elétricos gerados artificialmente. Foram realizados diferentes experimentos para avaliar a proposta de aplicação da snake-3D. Inicialmente, algumas características geométricas dos arcos foram reproduzidas em curvas paramétricas cujas projeções, sobre seções de planos, formaram as sequências de pares de imagens e determinaram os conjuntos de casos experimentais. Em seguida os resultados obtidos através da aplicação da snake-3D foram analisados comparativamente a outros métodos de reconstrução 3D frente aos valores verdadeiros dos comprimentos das curvas. Também foram realizados experimentos com um objeto concreto, nesse caso, um neon flexível manipulado defronte a um par de câmeras reais. As matrizes de calibração foram determinadas por meio de procedimento específico, o comprimento verdadeiro do objeto foi estimado por meio de medição direta e comparado aos resultados obtidos através da aplicação da snake-3D e outro método de reconstrução 3D. Em seguida a snake-3D foi aplicada a imagens de arcos elétricos reais cuja evolução foi capturada utilizando câmeras reais. Nesses casos as estimativas dos comprimentos por meio de snake-3D foram contrapostas aos estudos baseados na análise dos sinais de tensão e de corrente medidos nas extremidades do arco em evolução. Os comprimentos obtidos com a abordagem proposta foram semelhantes aos obtidos através de medidas elétricas, o que valida o uso da metodologia desenvolvida para este tipo de aplicaçãoAbstract: The electrical arc length is an important parameter for the arc mathematical modeling. Nowadays the profile of the arc length variation is estimated by the analysis of the voltage measured at the extremities of the arc and the current of the arc. But these results are not conclusive because they do not present a metrical measurement of the three-dimensional medial-axis of the arc. On the other hand, the images of the spatial evolution of the arc can provide enough resources for recovering the 3D longitudinal axis for estimation of the arc length as well as for obtaining the curve of length variation along the time. The main contribution of this work therefore lies in the estimation of the arc length, and consequently the elongation of electric arcs based on the application of the model (3D-snake) for the three-dimensional reconstruction of the longitudinal axes of artificially generated electrical arcs. Different experiments were conducted to evaluate the proposed application of the 3D-snake. Initially, some geometrical characteristics of the arcs were reproduced in parametric curves whose projections formed sequences of image pairs and determined the sets of test cases. Then the results obtained by applying the 3D-snake were analyzed in comparison to other 3D reconstruction methods against the true values of the lengths of curves. Also experiments were performed with a concrete object, in this case, a flexible neon manipulated in front of a pair of real cameras. The calibration matrices were determined by specific procedure, the length of the real object was estimated by direct measurement and compared to results obtained by applying the 3D-snake and other 3D reconstruction method. Next the 3D-snake was applied to real images of arcs whose evolutions were captured using real cameras. In these cases the estimation of measurement through 3D-snake were opposed to results based on arc current and arc voltage measured at arc terminals. The lengths obtained with the proposed model were similar to those obtained through electrical measurements, which validates the use of the method developed for this type of applicationDoutoradoEngenharia de ComputaçãoDoutor em Engenharia Elétric