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Confinamento de partículas quânticas a curvas do espaço
(Universidade Federal de São Carlos, 2010-05-24) Verri, Alessandra Aparecida; Oliveira, César Rogério de; https://lattes.cnpq.br/5485204156806697; https://lattes.cnpq.br/8794549732815622
In this work we study dimensional reductions in some quantum systems; such reductions occur due to confinement of the particle from a tube in space to a curve. Our main goal is to find the effective hamiltonian operator that describes the motion of the particle after confinement. We consider three particular situations. (1) In the first situation, we study an infinitely long tube generated by a curve with non-trivial torsion and curvature. Here the tube cross sections always have the same diameter. (2) We also study tubes in space deformed in a specific way, i.e., the diameter of the cross sections have a unique global maximum. Such tubes also have non-trivial torsion and curvature. (3) Finally, we analyze the question of which self-adjoint extension of the one-dimensional hydrogen atom would be physically relevant. We consider such atom in a three-dimensional tube and take the limit as the tube converges to the x axis, and it is shown that the Dirichlet (at the origin) extension is always obtained after such confinement.
Avaliação do papel do pulso de inundação sobre a riqueza e biodiversidade de peixes em ambiente inundável, no sistema de baías Caiçara, porção norte do Pantanal Matogrossense, alto Paraguai
(Universidade Federal de São Carlos, 2010-05-24) Muniz, Claumir Cesar; Peret, Alberto Carvalho; https://lattes.cnpq.br/0995579236780271; https://lattes.cnpq.br/2202899559144774
The present study was aimed to assess the role of the flood pulse related to the composition of the ichthyofauna of the Caiçara Basin System (Upper Baía Caiçara/UBC e Lower Baía Caiçara/LBC) in a pantanal environment, in Cáceres, Mato Grosso. 90,041 specimens were collected from September 2005 to September 2007, distributed in two classes, 8 orders, 32 families and 171 species, with 145 of them occurring in both environments. Characiforms, Siluriforms and Gymnotiforms were the most representative orders accounting for more than 90% of all the species obtained in the sampled environments. The UBC, with 155 collected species, considering the two sampled cycles, obtained 68 and 81 constant species, accounting for 50 and 56% of the total species in this bay. In the LBC, with 161 sampled species, the constant species were most significant, with respectively 43 and 56% per cycle and 54 species for the entire sampling period. Odontostilbe pequira, Serrapinnus calliurus and Moenkhausia dichroura were abundant in all the periods. M. dichroura was the most abundant species in practically all the periods and environments. Cyphocharax gillii and Hypoptopoma inexspectatum (detritivores) were abundant in the ebb tide and dry periods. Acestrorhynchus pantaneiro and Roeboides prognathus were the most abundant piscivores in the ebb tide period. Hemiodus orthonops was abundant in the flood and high tide periods. Among the invertivores/insectivores, M. dichroura and O. pequira were abundant in all the seasonal periods. Concomitantly to the fish collection, data from the limnological variables in the two sampled environments were also obtained, which showed significant differences between the seasonal periods. In the dry periods, the UBC remained totally disconnected from the Paraguay River, and the BCI obtained a smaller water amount from the main channel. In the flood period the connectivity between the UBC and the Paraguay River was reestablished. The concentration of dissolved oxygen varied from 0.67 to 5.94 mg/l in BCS and 0.64 and 5.87 mg/l in the LBC. The highest water temperatures were observed during the flood period (31.35 °C) and the lowest temperature during the dry period (22.33°C). Concerning electrical conductivity, the highest values were observed in the flood period (84.19 μS.cm-1). The lowest values were obtained in the ebb tide period (23.30 μS.cm-1). It obtained the lowest pH values (5.66) in the high tide period, and the highest pH values (7.50) in the dry period. Characiforms and Siluriforms were the orders that showed the best adaptation to the variations caused by the flood pulse of this system and the limnological attributes (dissolved oxygen, pH, electrical conductivity in water, pH, water transparency and depth) are decisive in the arrangement of the ichthyofauna, but their action is not isolated. On the contrary, they are interdependent together with the river-basin connectivity.
O fitoplâncton como instrumento de biomonitoramento da qualidade da água do Reservatório de Cachoeira Dourada - Rio Paranaíba - GO/MG
(Universidade Federal de São Carlos, 2010-05-24) Oliveira, Márcia Teixeira de; Peret, Alberto Carvalho; https://lattes.cnpq.br/0995579236780271; https://lattes.cnpq.br/7107251497009712
The phytoplankton community is one of the communities recommended as a tool for evaluations of water quality. The relevance of ecological and sanitary studies of phytoplankton to public health is due to the fact that they attest to water quality and allow waters to be monitored for multiple uses, especially those linked directly to human health. The phytoplankton community of the Cachoeira Dourada reservoir was characterized in the months of December 2006, May 2007 and November 2007 at five sampling points, four of them in the reservoir and one downstream. The phytoplankton sampling, which was based on the principles of the AquaRAP, aimed to evaluate water quality using indices based on physical, chemical and biological characteristics, with emphasis on the phytoplankton community. The results revealed that the phytoplankton was dominated by cyanobacteria in the three sampling periods. Cyanobacteria exhibited higher significance in terms of richness and greater density than the other classes of phytoplankton. Potentially toxic species were represented by Anabaena sp. and Microcystis sp., with higher occurrence during the dry season, albeit in low densities. There was no record of blooming and the analyzed densities lay within the limit established by CONAMA (National Environmental Agency). The reservoir was classified as oligotrophic, based on its phytoplankton diversity, equitability, richness and density. This classification was confirmed by an analysis of the reservoir s physical and chemical variables and by several other indices applied with or without the use of the phytoplankton community. Among the various indices employed, Nygaard s index was the only one considered inefficient in evaluating the trophic degree of the reservoir, because it neglects species density. Phytoflagellates proved to be a good indicator of environments with low transparency (CCA). The main interferents in the reservoir s water quality were found to depend on factors of climate, the dam s operation, and anthropic activities in adjacent areas and in the drainage basin, which were dynamically reflected in the composition and structure of the phytoplankton community in the different periods under study. It is also important to note that the brief residence time of the water is probably the preponderant factor for this oligotrophic state of the reservoir.
Análise da superfície de porcelanatos polidos por meio de microscopia de força atômica
(Universidade Federal de São Carlos, 2010-05-24) Fernandes, Mérilin Cristina dos Santos; Paulin Filho, Pedro Iris; https://lattes.cnpq.br/9542027656569433; https://lattes.cnpq.br/2740250822457796
The porcelain stoneware tile is a ceramic product that has presented a great increase on production, since it had excellent technical properties and raised aesthetic performance. To improve its aesthetic characteristics, it is submitted to a polishing process that influences a lot of interested properties of the products, due mainly to changes observed on the superficial roughness. In this way, the roughness was investigated throughout the superficial polishing process of the glazed and unglazed (technical) porcelain stoneware tile and it was correlated with the gloss. For this, the Atomic Force Microscope (AFM) was used, being ideal to measure the roughness in nanometer scale and to visualize the nanotexture of many types of surface materials. The specular part of the gloss was measured through the equipment known as glossmeter. The results achieved shown that the technical porcelain stoneware tile in the first stage is more rough than the glazed. On the technical porcelain stoneware tile the roughness reduction was more accented between the grit 80 and 1000 stages, and the gloss was practically double between the first and the last (POLIDO) stages. The surface covering with the polymeric resin reduced significantly the product gloss, without it causes brusque alterations in superficial roughness. On the glazed porcelain stoneware tile the roughness reduction and the gloss increased occurred mainly between the grit 600 and 1800 stages. Between the grit 1800 and 8000 stages had not observed great changes on the roughness or gloss, showing that the polishing becomes unnecessary from the grit 1800. In general way, the gloss reduction occurred more visibly in stages of polishing with abrasives of larger grains, while the abrasives of smaller grains had given the final gloss, intervene poorly in roughness. The results interpretation had supplied subsidies to a better understanding and control of the process responsible for the final characteristics between the glazed and technical products, and the differences between these typologies.
Novas propostas em filtragem de projeções tomográficas sob ruído Poisson
(Universidade Federal de São Carlos, 2010-05-24) Ribeiro, Eduardo da Silva; Mascarenhas, Nelson Delfino d'Ávila; https://lattes.cnpq.br/0557976975338451; https://lattes.cnpq.br/5036975831625237
In this dissertation we present techniques for filtering of tomographic projections with Poisson noise. For the filtering of the tomogram projections we use variations of three filtering techniques: Bayesian estimation, Wiener filtering and thresholding in Wavelet domain. We used ten MAP estimators, each estimator with a diferent probability density as prior information. An adaptive windowing was used to calculate the local estimates. A hypothesis test was used to select the best probability density to each projection. We used the Pointwise Wiener filter and FIR Wiener Filter, in both cases we used a adaptive scheme for the filtering. For thresholding in wavelet domain, we tested the performance of four families basis of wavelet functions and four techniques for obtaining thresholds. The experiments were done with the phantom of Shepp and Logan and five set of projections of phantoms captured by a CT scanner developed by CNPDIA-EMBRAPA. The image reconstruction was made with the parallel POCS algorithm. The evaluation of the filtering was made after reconstruction with the following criteria for measurement of error: ISNR, PSNR, SSIM and IDIV.