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Made available in DSpace on 2014-12-17T15:36:51Z (GMT). No. of bitstreams: 1 EmmanuelMS.pdf: 693776 bytes, checksum: 5c59a44ad86ae5501127668e2496f494 (MD5) Previous issue date: 2008-03-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The use of habitat is an important part of a species biology. One resource of great importance for the survivor and reproduction of an individual is the food resource. Thus, the social interactions an animal has during the feeding activities are of extremely importance within its behavioral aspects, which represents the part of an organism trough which it interacts with the environment, adapting to changes and variations. Herons are known to form feeding aggregations of even more than thousands of individuals, in which social components of foraging have been identified and studied for several species. More profound studies of these aspects are yet to poor for the Little Blue Heron, Egretta caerulea. Therefore, the aim of this study was to describe the social behavior (display postures, vocalizations and co-specific interactions) and the territoriality of the specie during the feeding period in an area of mud bank in the estuarine system of Canan?ia, south coast of S?o Paulo state, Brazil. The defense of a fixed and exclusive area, closest to the mangrove, trough expulsion was observed; some thing that have not yet been registered with concrete data for the specie. Higher capture and success rates, and lower investment rates (steps/min and stabs/min) were registered for individuals foraging in areas corresponding to the defended territory. This could be one of possible reasons for the establishment of territories in the area. Four display postures were registered for the specie, two of then new in the literature, which are used in the interactions between individuals; one vocalization, that apparently is important in the social context of foraging for the specie and, possibly, has a function of advertising and proclaiming the dominance position of the territorial individual within the group. A territorial individual uses three behaviors, of the ones described: expulsion, vocalization and encounter (agonistic encounter between individuals, without physical aggression). Of these, the expulsion is apparently used in the actual defense, actively; while the other two behaviors are used in a more passive way, in the maintenance of the dominance position of the individual, helping it in the defense of its territory in a less direct manner. Therefore, with the results presented in here, new components of the social utilization of the feeding resource for the Little Blue Heron were identified, incorporating aspects of the territorial behavior for a future understanding of its possible adaptive significance. And it also reinforces the importance of the social interactions of herons foraging in great aggregations, in areas ecologically important / A utiliza??o do habitat ? parte importante da biologia de uma esp?cie. Um dos recursos importantes para a sobreviv?ncia e reprodu??o de um indiv?duo ? o recurso alimentar. Desta forma, as intera??es sociais que um animal mant?m durante as atividades de forrageio s?o de suma import?ncia dentre seus aspectos comportamentais, os quais, por sua vez, representam a parte de um organismo atrav?s da qual este interage com o ambiente, adaptando-se as varia??es e mudan?as no meio. Gar?as s?o conhecidas por formar agrega??es alimentares que podem conter at? milhares de indiv?duos, nas quais componentes sociais do forrageio t?m sido identificados e estudados para v?rias esp?cies. Estudos mais aprofundados destes aspectos ainda s?o escassos para a gar?a-azul, Egretta caerulea. Desta forma, o objetivo deste estudo foi descrever o comportamento social (posturas de exibi??o, vocaliza??es e intera??es co-espec?ficas) e a territorialidade da esp?cie durante o per?odo de forrageio em uma ?rea de baixio lodoso no sistema estuarino de Canan?ia, litoral sul do estado de S?o Paulo, Brasil. Observou-se a defesa de uma ?rea fixa e exclusiva, pr?xima ao manguezal, atrav?s da expuls?o; algo que ainda n?o tinha sido registrado com dados concretos para a esp?cie. Registraram-se taxas de captura e sucesso maiores para indiv?duos forrageando na ?rea correspondente ao territ?rio defendido, assim como menores taxas de investimento no forrageio. Desta forma, esta pode ser uma das raz?es pelo estabelecimento de territ?rios pela esp?cie no local. Registraram-se quatro posturas de exibi??o para a esp?cie, das quais duas s?o novas na literatura e s?o utilizadas nas intera??es entre indiv?duos. Registrou-se uma vocaliza??o, que aparentemente ? importante no contexto social do forrageio para a esp?cie e, possivelmente, tem fun??o de advert?ncia e proclama??o da posi??o de domin?ncia ocupada pelo indiv?duo territorial dentro do grupo. Um indiv?duo territorial utiliza-se de tr?s comportamentos, dos descritos: expuls?o, vocaliza??o e encontro (encontro agon?stico entre indiv?duos, sem agress?o f?sica). Destes, aparentemente a expuls?o ? utilizada na defesa ativa; enquanto que os outros dois comportamentos s?o utilizados de uma forma mais passiva, na manuten??o da posi??o de domin?ncia do indiv?duo, ajudando-o na defesa de seu territ?rio de uma forma menos direta. Assim, com os resultados apresentados neste trabalho, identificaram-se novos componentes do comportamento social da utiliza??o do recurso alimentar pela gar?a-azul, incorporando-se aspectos do comportamento territorial para um futuro entendimento de sua poss?vel signific?ncia adaptativa. Refor?a-se tamb?m a import?ncia das intera??es sociais de gar?as que forrageiam em agregados contendo milhares de indiv?duos, em ?reas ecologicamente importantes

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The phenomenon of spray in crossflow is of relevance in gas turbine combustor development. The current work focuses on spray in crossflow rather than liquid jet in crossflow from the standpoint of enhancing fuel dispersion and mixing. Specifically, the first part of the work involves study of spray structure, droplet sizing, and velocimetry for sprays of water and ethanol in a crossflow under ambient conditions. Laser-based diagnostic techniques such as Particle/Droplet Image Analysis (PDIA) and Particle Tracking Velocimetry (PTV) are utilized. Using spray structure images, trajectory equations are derived by multi-variable regression. It is found that the spray trajectory depends only on the two-phase momentum ratio and is independent of other flow parameters. A generalized correlation for the spray trajectory is proposed incorporating the liquid surface tension, which is found to be effective for our data, with water and ethanol, as well as data on Jet-A from the literature for a wide variety of operating conditions. An interesting phenomenon of spatial bifurcation of the spray is observed at low Gas-to-Liquid ratios (GLRs). The reason for this phenomenon is attributed to the co-existence of large and highly deformed ligaments along with much smaller droplets at low GLR conditions. The smaller droplets lose their vertical momentum rapidly leading to lower penetration, whereas the larger ligaments/droplets penetrate much more due to their larger momentum leading to a spatial separation of the two streams. The second part of the study focuses on evaporating sprays in preheated crossflow. Experiments are conducted using ethanol, decane, Jet-A1 fuel, and a two-component surrogate for Jet-A1 fuel. The crossflow air is heated up to 418 K and the effect of evaporation is studied on spray trajectory and droplet sizes. Measured droplet sizes and velocities at two successive locations are used to estimate droplet evaporation lifetimes. Evaporation constant for the d2 law derived from the droplet lifetimes represents the first-ever data for the above-mentioned liquids under forced convective conditions. This data can be used to validate multi-component droplet evaporation models. The last part of the study focuses on Large Eddy Simulations (LES) of the spray in crossflow. The near-nozzle spray structure is investigated experimentally to obtain droplet size and velocity distributions that are used as inputs to the computational model. For the spray in crossflow under ambient conditions, trajectory and droplet sizes at different locations are compared with experimental results. While the predicted trajectory is found to be in good agreement with data, the predicted droplet sizes are larger than the measured values. This is attributed to the implicit assumption in the secondary breakup model that the droplets are spherical, whereas the experimental data in the near-nozzle region clearly shows presence of mostly ligaments and non-spherical droplets, especially for the low GLR cases. A modified breakup model is found to lead to improved agreement in droplet sizes between predictions and measurements. Overall, the experiments and computations have provided significant insight into spray in crossflow phenomenon, and have yielded useful results in terms of validated spray trajectory correlations, droplet evaporation lifetimes under forced convective conditions, and a methodology for simulation of airblast sprays.

The thesis deals the issue of solution of continuous systems by evolutionary computational techniques. Evolutionary computing techniques fall into the field of softcomputing, an advanced metaheuristics optimization that is becoming more and more a method of solving complicated optimization problems with the gradual increase in computing performance of computers. The solution of continuous systems, or the synthesis of continuous control circuits, is one of the areas where these advanced algorithms find their application. When dealing with continuous systems we will focus on regulatory issues. Evolutionary computing can then become a tool not only for optimization of controller parameters but also to design its structure. Various algorithms (genetic algorithm, differential evolution, etc.) can be used to optimize the parameters of the controller, for the design of the controller structurewe usually encounter so called grammatical evolution. However, the use of grammatical evolution is not necessary if appropriate coding is used, as suggested in the presented thesis. The thesis presents a method of designing the structure and parameters of a general linear controller using the genetic algorithm. A general linear regulator is known also as so called polynomial controller, if we encounter the polynomial theory of control. The method of encoding the description of the general linear controller into the genetic chain is crucial, it determines a set of algorithms that are usable for optimization and influence the efficiency of the calculations. Described coding, effective EVT implementation, including multi-criteria optimization, is a key benefit of this work.