As mudanças na organização, nos processos e nas relações de trabalho, que estão no bojo do processo de reestruturação produtiva capitalista, se intensificaram a partir das últimas décadas do século XX, resultando em um quadro de agravamento das condições de trabalho que interfere diretamente nas condições de saúde dos trabalhadores de forma geral. Esta pesquisa se debruça sobre estas questões, tomando como objeto de investigação a atividade laboral dos trabalhadores do setor de alimentos empregados em uma unidade de processamento de aves, pertencentes a uma das maiores empresas deste ramo no país, localizada na região oeste do Estado do Paraná. A metodologia adotada para esta pesquisa foi de cunho qualitativo e foram utilizadas como instrumento de coleta de dados, entrevistas abertas. Ao todo foram entrevistados dez trabalhadores, de ambos os sexos, que foram contatados através da técnica de indicação sucessiva, somando aproximadamente 5h e 30m de gravação. Foram também realizadas entrevistas com a psicóloga e com o presidente do sindicato a qual estão vinculados os trabalhadores desta indústria avícola. A partir das informações obtidas com os trabalhadores foi realizada a reconstituição do processo de trabalho observando a sua dinâmica (destacando as questões referentes à organização e divisão do trabalho e aquelas relacionadas ao uso de tecnologias), e a descrição do ambiente de trabalho; visando compreender como são as condições de trabalho para saber se as mesmas interferem na saúde dos trabalhadores. A análise dos conteúdos das entrevistas revelou que a organização do trabalho fundada nos preceitos taylorista/fordista predominante naquele setor, foi acrescida por outras técnicas de organização da produção e do trabalho, inspiradas no modelo japonês ou toyotista, e que estão interferindo nas condições de saúde dos trabalhadores tanto física quanto psíquica. O crescimento de casos de LER na categoria aparece de forma destacada nos depoimento colhidos. / The changes in organization, in work processes and relationships that are basic for the capitalist productive restructuring process, which have been intensified for the last decades in the 20th century, have resulted in a state of working conditions aggravation, which directly interferes in the workers´ health conditions, in general. This paper delves into these questions, having as its investigation object the workers´ labor activities in the food sector, who were employed in a poultry processing plant which belongs to one of the country´s largest companies in its field, located in the west of Paraná state. The adopted methodology for this research was qualitative, and it was used as an instrument for data collection in open interviews. Altogether, ten employees of both sexes were interviewed, who were contacted through the successive indication technique, logging approximately a 5-hour-and-30-minute recording. There was also an interview with the psychologist and the president of the union these poultry plant´s workers are associated with. Based on the information obtained from the workers, the reconstitution of the work process was conducted, observing its dynamics (pointing out the issues referring to work organization and division and those related to the use of technologies), and the description of the work setting, with a view to understand what the working conditions are like and discover if they interfere in the employees´ health. The analysis done on the contents of the interviews revealed that the work organization fashioned around Taylorist/Fordist precepts, predominant in that sector, was increased by other organization techniques for production and work, inspired by the Japanese model (or Toyotist), and that they have been interfering in the workers´ physical and mental health conditions. The increasing number of LRE cases in this category is outstandingly apparent in the testimonies.

As mudanças na organização, nos processos e nas relações de trabalho, que estão no bojo do processo de reestruturação produtiva capitalista, se intensificaram a partir das últimas décadas do século XX, resultando em um quadro de agravamento das condições de trabalho que interfere diretamente nas condições de saúde dos trabalhadores de forma geral. Esta pesquisa se debruça sobre estas questões, tomando como objeto de investigação a atividade laboral dos trabalhadores do setor de alimentos empregados em uma unidade de processamento de aves, pertencentes a uma das maiores empresas deste ramo no país, localizada na região oeste do Estado do Paraná. A metodologia adotada para esta pesquisa foi de cunho qualitativo e foram utilizadas como instrumento de coleta de dados, entrevistas abertas. Ao todo foram entrevistados dez trabalhadores, de ambos os sexos, que foram contatados através da técnica de indicação sucessiva, somando aproximadamente 5h e 30m de gravação. Foram também realizadas entrevistas com a psicóloga e com o presidente do sindicato a qual estão vinculados os trabalhadores desta indústria avícola. A partir das informações obtidas com os trabalhadores foi realizada a reconstituição do processo de trabalho observando a sua dinâmica (destacando as questões referentes à organização e divisão do trabalho e aquelas relacionadas ao uso de tecnologias), e a descrição do ambiente de trabalho; visando compreender como são as condições de trabalho para saber se as mesmas interferem na saúde dos trabalhadores. A análise dos conteúdos das entrevistas revelou que a organização do trabalho fundada nos preceitos taylorista/fordista predominante naquele setor, foi acrescida por outras técnicas de organização da produção e do trabalho, inspiradas no modelo japonês ou toyotista, e que estão interferindo nas condições de saúde dos trabalhadores tanto física quanto psíquica. O crescimento de casos de LER na categoria aparece de forma destacada nos depoimento colhidos. / The changes in organization, in work processes and relationships that are basic for the capitalist productive restructuring process, which have been intensified for the last decades in the 20th century, have resulted in a state of working conditions aggravation, which directly interferes in the workers´ health conditions, in general. This paper delves into these questions, having as its investigation object the workers´ labor activities in the food sector, who were employed in a poultry processing plant which belongs to one of the country´s largest companies in its field, located in the west of Paraná state. The adopted methodology for this research was qualitative, and it was used as an instrument for data collection in open interviews. Altogether, ten employees of both sexes were interviewed, who were contacted through the successive indication technique, logging approximately a 5-hour-and-30-minute recording. There was also an interview with the psychologist and the president of the union these poultry plant´s workers are associated with. Based on the information obtained from the workers, the reconstitution of the work process was conducted, observing its dynamics (pointing out the issues referring to work organization and division and those related to the use of technologies), and the description of the work setting, with a view to understand what the working conditions are like and discover if they interfere in the employees´ health. The analysis done on the contents of the interviews revealed that the work organization fashioned around Taylorist/Fordist precepts, predominant in that sector, was increased by other organization techniques for production and work, inspired by the Japanese model (or Toyotist), and that they have been interfering in the workers´ physical and mental health conditions. The increasing number of LRE cases in this category is outstandingly apparent in the testimonies.

The understanding and prediction of transient phenomena inside Liquid Rocket Engines (LREs) have been very difficult because of the many challenges posed by the conditions inside the combustion chamber. This is especially true for injectors involving liquid oxygen LOX and gaseous hydrogen GH₂. A wide range of length scales needs to be captured from high-pressure flame thicknesses of a few microns to the length of the chamber of the order of a meter. A wide range of time scales needs to be captured, again from the very small timescales involved in hydrogen chemistry to low-frequency longitudinal acoustics in the chamber. A wide range of densities needs to be captured, from the cryogenic liquid oxygen to the very hot and light combustion products. A wide range of flow speeds needs to be captured, from the incompressible liquid oxygen jet to the supersonic nozzle. Whether one desires to study these issues numerically or experimentally, they combine to make simulations and measurements very difficult whereas reliable and accurate data are required to understand the complex physics at stake. This thesis focuses on the numerical simulations of flows relevant to LRE applications using Large Eddy Simulations (LES). It identifies the required features to tackle such complex flows, implements and develops state-of-the-art solutions and apply them to a variety of increasingly difficult problems. More precisely, a multi-species real gas framework is developed inside a conservative, compressible solver that uses a state-of-the-art hybrid scheme to capture at the same time the large density gradients and the turbulent structures that can be found in a high-pressure liquid rocket engine. Particular care is applied to the implementation of the real gas framework with detailed derivations of thermodynamic properties, a modular implementation of select equations of state in the solver. and a new efficient iterative method. Several verification cases are performed to evaluate this implementation and the conservative properties of the solver. It is then validated against laboratory-scaled flows relevant to rocket engines, from a gas-gas reacting injector to a liquid-gas injector under non-reacting and reacting conditions. All the injectors considered contain a single shear coaxial element and the reacting cases only deal with H₂-O₂ systems. A gaseous oyxgen-gaseous hydrogen (GOX-GH₂) shear coaxial injector, typical of a staged combustion engine, is first investigated. Available experimental data is limited to the wall heat flux but extensive comparisons are conducted between three-dimensional and axisymmetric solutions generated by this solver as well as by other state-of-the-art solvers through a NASA validation campaign. It is found that the unsteady and three-dimensional character of LES is critical in capturing physical flow features, even on a relatively coarse grid and using a 7-step mechanism instead of a 21-step mechanism. The predictions of the wall heat flux, the only available data, are not very good and highlight the importance of grid resolution and near-wall models for LES. To perform more quantitative comparisons, a new experimental setup is investigated under both non-reacting and reacting conditions. The main difference with the previous setup, and in fact with most of the other laboratory rigs from the literature, is the presence of a strong co-flow to mimic the surrounding flow of other injecting elements. For the non-reacting case, agreement with the experimental high-speed visualization is very good, both qualitatively and quantitatively but for the reacting case, only poor agreement is obtained, with the numerical flame significantly shorter than the observed one. In both cases, the role of the co-flow and inlet conditions are investigated and highlighted. A validated LES solver should be able to go beyond some experimental constraints and help define the next direction of investigation. For the non-reacting case, a new scaling law is suggested after a review of the existing literature and a new numerical experiment agrees with the prediction of this scaling law. A slightly modified version of this non-reacting setup is also used to investigate and validate the Linear-Eddy Model (LEM), an advanced sub-grid closure model, in real gas flows for the first time. Finally, the structure of the trans-critical flame observed in the reacting case hints at the need for such more advanced turbulent combustion model for this class of flow.

Combustion instability due to feedback coupling between unsteady heat release and natural acoustic modes can cause catastrophic failure in liquid rocket engines and to predict and prevent these instabilities the mechanisms that drive them must be further elucidated. With this goal in mind, the objective of this thesis was to develop techniques that improve the understanding of the specific underlying physical processes involved in these driving mechanisms. In particular, this work sought to develop a small-scale, optically accessible liquid rocket engine simulator and to apply modern, high-speed diagnostic techniques to characterize the reacting flow and acoustic field within the simulator. Specifically, high-speed (10 kHz), simultaneous data were acquired while the simulator was experiencing a 170 Hz combustion instability using particle image velocimetry, OH planar laser induced fluorescence, CH* chemiluminescence, and dynamic pressure measurements. In addition, this work sought to develop approaches to reduce the large quantities of data acquired, extracting key physical phenomena involved in the driving mechanisms. The initial data reduction approach was chosen based on the fact that the combustion instability problem is often simplified to the point that it can be characterized by an approximately linear constant coefficient system of equations. Consistent with this simplification, the experimental data were analyzed by the dynamic mode decomposition method. The developed approach to apply the dynamic mode decomposition to simultaneously acquired data located a coupled hydrodynamic/combustion/acoustic mode at 1017 Hz. On the other hand, the dynamic mode decomposition's assumed constant operator approach failed to locate any modes of interest near 170 Hz. This led to the development of two new data analysis techniques based on the dynamic mode decomposition and Floquet theory that assume that the experiment is governed by a linear, periodic system of equations. The new periodic-operator data analysis techniques, the Floquet decomposition and the ensemble Floquet decomposition, approximate, from experimental data, the largest moduli Floquet multipliers, which determine the stability of the periodic solution trajectory of the system. The unstable experiment dataset was analyzed with these techniques and the ensemble Floquet decomposition analysis found a large modulus Floquet multiplier and associated mode with a frequency of 169.6 Hz. Furthermore, the approximate Rayleigh criterion indicated that this mode was unstable with respect to combustion instability. Overall, based on the positive finding that the ensemble Floquet decomposition was able to locate an unstable combustion mode at 170 Hz when the operator's time period was set to 1 ms, suggests that the dynamic mode decomposition based 1017 Hz mode parametrically forces the 170 Hz mode, resulting in what could be characterized as a parametric combustion instability.

No description available.

This PhD thesis deals with the use of structural methods of objects identification for industrial robots operation. First, the present state of knowledge in the field is described, i.e. the whole process of objects recognition with the aid of common methods of the syntactic analysis. The main disadvantage of these methods is that is impossible to recognize objects whose digitalized image is corrupted in some ways (due to excessive noise or image disturbances), objects are therefore deformed. Further, other methods for the recognition of deformed objects are described. These methods use structural description of objects for object recognition, i.e. methods which determine the distance between attribute descriptions of images. The core part of this PhD thesis begins in Chapter 5, where deformation grammars, capable of description of all possible object deformations, are described. The only complication in the analysis is the ambiguity of the deformation grammar, which lowers the effectiveness of the analysis. Further, PhD thesis deals with the selection and modification of a proper parser, which is able to analyze a deformation grammar effectively. Three parsers are described: the modified Earley parser, the modified Tomita parser and the modified hybrid LRE(k) parser. As for the modified Earley’s parser, ways of its effective implementation are described. One of the necessary parts of the object recognition is providing the invariances, which this PhD thesis covers in detail, too. Finally, the results of described algorithms are mentioned (successfulness and speed of deformed objects recognition) and suggested testing environment and implemented algorithms are described. In conclusion, all determined possibilities of deformation grammars and their results are summarized.

No description available.