Esta dissertação aborda a caracterização mecânica de um robô manipulador paralelo de 3 graus de liberdade. A topologia do manipulador corresponde a um mecanismo de estrutura cinemática paralela, cujo efetuador é capaz de realizar 3 deslocamentos lineares no espaço tridimensional. A tecnologia associada ao controle de robôs de estrutura cinemática serial encontra-se bastante madura. No entanto, o mesmo não se dá nos robôs paralelos. Para que se avance no domínio do controle de trajetória destes robôs é necessária a sua caracterização mecânica, a qual fornecerá os subsídios para identificação paramétrica, calibração de modelos, ajuste de ganhos dos controladores, etc. Especificamente, a caracterização mecânica neste trabalho teve por objetivo o levantamento experimental dos erros de posicionamento do efetuador com relação a exatidão e repetibilidade, sua rigidez sob a ação de cargas externas, bem como das frequências naturais do sistema. Os ensaios realizados foram executados no robô Laila, que é um protótipo físico de um robô manipulador, desenvolvido pelo Departamento de Engenharia Mecatrônica e Sistemas Mecânicos da Escola Politécnica da Universidade de São Paulo. A dissertação apresenta como resultados os mapeamentos dos erros de posicionamento do efetuador, a rigidez sob a ação de cargas externas, bem como suas frequências naturais, ao longo do espaço de medição. A seguir, apresenta-se uma discussão da consistência dos valores obtidos para estas propriedades. Por fim, é feita uma análise sobre a influência das folgas mecânicas sobre os índices de desempenho do robô. / This dissertation deals with the mechanical characterization of a parallel manipulator robot of 3 degrees of freedom. The topology of the manipulator corresponds to a mechanism of parallel kinematic structure, whose effector is capable of performing 3 linear displacements in the three-dimensional space. The technology associated with the control of robots of serial kinematic structure is quite mature. However, the same is not true of parallel robots. In order to advance in the field of control of trajectory of these robots it is necessary to characterize them mechanically, which will provide the subsidies for parametric identification, calibration of models, adjustment of gains of the controllers, etc. Specifically, the mechanical characterization in this work had as objective the experimental study of the positioning errors of the effector in relation to the accuracy and repeatability, its rigidity under the action of external loads, as well as the natural frequencies of the system. The tests were performed in the Laila robot, which is a physical prototype of a manipulator robot, developed by the Department of Mechatronics Engineering and Mechanical Systems of the Polytechnic School of the University of São Paulo. The dissertation presents as results the mappings of the positioning errors of the effector, the rigidity under the action of external loads, as well as their natural frequencies, along the measurement space. The following is a discussion of the consistency of the values obtained for these properties. Finally, an analysis is made on the influence of the mechanical gaps on the performance indexes of the robot.

Esta dissertação aborda a caracterização mecânica de um robô manipulador paralelo de 3 graus de liberdade. A topologia do manipulador corresponde a um mecanismo de estrutura cinemática paralela, cujo efetuador é capaz de realizar 3 deslocamentos lineares no espaço tridimensional. A tecnologia associada ao controle de robôs de estrutura cinemática serial encontra-se bastante madura. No entanto, o mesmo não se dá nos robôs paralelos. Para que se avance no domínio do controle de trajetória destes robôs é necessária a sua caracterização mecânica, a qual fornecerá os subsídios para identificação paramétrica, calibração de modelos, ajuste de ganhos dos controladores, etc. Especificamente, a caracterização mecânica neste trabalho teve por objetivo o levantamento experimental dos erros de posicionamento do efetuador com relação a exatidão e repetibilidade, sua rigidez sob a ação de cargas externas, bem como das frequências naturais do sistema. Os ensaios realizados foram executados no robô Laila, que é um protótipo físico de um robô manipulador, desenvolvido pelo Departamento de Engenharia Mecatrônica e Sistemas Mecânicos da Escola Politécnica da Universidade de São Paulo. A dissertação apresenta como resultados os mapeamentos dos erros de posicionamento do efetuador, a rigidez sob a ação de cargas externas, bem como suas frequências naturais, ao longo do espaço de medição. A seguir, apresenta-se uma discussão da consistência dos valores obtidos para estas propriedades. Por fim, é feita uma análise sobre a influência das folgas mecânicas sobre os índices de desempenho do robô. / This dissertation deals with the mechanical characterization of a parallel manipulator robot of 3 degrees of freedom. The topology of the manipulator corresponds to a mechanism of parallel kinematic structure, whose effector is capable of performing 3 linear displacements in the three-dimensional space. The technology associated with the control of robots of serial kinematic structure is quite mature. However, the same is not true of parallel robots. In order to advance in the field of control of trajectory of these robots it is necessary to characterize them mechanically, which will provide the subsidies for parametric identification, calibration of models, adjustment of gains of the controllers, etc. Specifically, the mechanical characterization in this work had as objective the experimental study of the positioning errors of the effector in relation to the accuracy and repeatability, its rigidity under the action of external loads, as well as the natural frequencies of the system. The tests were performed in the Laila robot, which is a physical prototype of a manipulator robot, developed by the Department of Mechatronics Engineering and Mechanical Systems of the Polytechnic School of the University of São Paulo. The dissertation presents as results the mappings of the positioning errors of the effector, the rigidity under the action of external loads, as well as their natural frequencies, along the measurement space. The following is a discussion of the consistency of the values obtained for these properties. Finally, an analysis is made on the influence of the mechanical gaps on the performance indexes of the robot.

Thesis (M.A.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Approximately a third of homicide cases go unsolved each year. Research focused on understanding what affects homicide clearance rates is often methodologically underdeveloped and has produced mixed findings. These deficiencies compromise the ability of researchers to provide important guidance to police practitioners seeking to develop best practices. Under-specified modeling and limited access to accurate sources of homicide investigation data are two potential and interconnected reasons for the inconsistencies found in previous studies. The purpose of this study was to expand the literature on homicide case outcomes as follows: 1) to organize predictors into five substantive domains (involved subjects, event circumstances, case dynamics, ecological characteristics, and investigator factors) and operationalize multiple measures of each as viable predictors of clearance outcomes; 2) to explore the utility of using original and verified police data with a larger number of nuanced data points than previously documented in modeling efforts; and 3) to forward a unique multi-method account of the factors that predict homicide case outcomes that can be readily replicated in future studies. Data were collected from one Southern metropolitan police department's 2009 to 2011 homicide investigations (N = 252). Access to official homicide case files allowed for key subject, incident, and evidentiary information to be obtained. Critical investigation details and context were added to the case file data via interviews and survey administration efforts involving the lead detectives that worked the cases. The dataset was further supplemented with Census data. Subsequent analyses included examination of the data quality and multivariate logistic regressions. A comparison of the dataset after the first stage of data collection to the final product was conducted to understand the extent to which the dataset were improved. The multi-method process resulted in more precision to the data recorded from case files, significant reductions in missing data, and heightened detail on key variables. Consequently those data allowed for specification of a multivariate model that included multiple measures from all of the homicide investigation domains. Those results suggest the expanded data more accurately captured the factors that predict clearance outcomes as measures within all five domains were significant predictors of investigation closure.

A systematic investigation of the human mind's ability to self-reflect and create private interpretations of sensory data has been handicapped for years by conceptual prejudice and methodological bias. Until the arrival of the cognitive behavior therapists, little empirical attention was directed to the development of a methodology adequate enough to investigate the influence that distorted cognitive interpretations have on emotional arousal and inhibited behavioral performance. This study investigated these self-reflective mental capabilities in terms of outcome expectancies which were conceptualized in terms of guilt, and self-perceptions of performance ability which were conceptualized in terms of successfully refusing unreasonable requests. It was hypothesized that guilt entails both emotional arousal as well as the distorted and fabricated cognitive perceptions of tragic expectation, causal attribution and self-perceived helplessness and that these perceptions influence behavioral performance and self-perceptions of performance ability. It was also hypothesized that guilt relates significantly to resentment and depression. Seventy-three subjects volunteered to participate: fifty-eight women and fifteen men with a mean age of thirty-three. Subjects responded to both self-report questionnaires and open-ended self-report interviews. Seven independent raters judged the participant's responses to eight tape recorded stimulus situations to determine to what extent the responses fit the hypothesized categories. A stepwise multiple regression was used to analyze the data. The results were summarized and placed in tables. The results of the study supported the five hypotheses developed to test the general question.

In this study a fiber optic interferometer (FOI) was designed and constructed to measure micron level clearances occurring in piston cylinder arrangements. A Cartesian model of the piston cylinder assembly is manufactured and lateral motion and vertical displacement are generated via a step motor, and micrometers, respectively. Clearance measurements are conducted in air and also in a lubricant. The range of vertical displacements is kept between 0-50 &amp / #956 / m, and the lateral motion is 13.5 mm. The effect of the step motor and lateral motion carriage on distance measurement is determined and this is used to correct displacement measurements.

This thesis reviews the line insulation coordination practices of Turkish Electricity Transmission Company with special focus on E.H.V. transmission line towers&rsquo / top geometry and ground clearances. In respect of this, the national regulation, &ldquo / Elektrik Kuvvetli Akim Tesisleri Y&ouml / netmeligi&rdquo / , is critically evaluated.The national regulation lags behind the modern world practice and the provisions of the regulation lead to uneconomical designs. The possible benefits of the modern practices are shown by application examples.

The concept of More Electric Aircraft, where is to utilize the electrical power to drive more or all aircraft subsystem instead of conventional combination of pneumatic, hydraulic, mechanical and electrical power, can be recalled to World War II. It has been proven to have more advantages for decades in terms of energy efficiency, environmental issues, logistics and operational maintenance. It can also enhance aircraft weight, volume and battle damage reconfigurability.Thanks to the new electronics technologies and the emergence of new materials, It becomes feasible for high power density electrical power components to drive the majority of aircraft subsystem. However, sustaining the transmission of hundreds of kilowatts of electrical power at low voltages is not feasible owing to the penalties incurred due to high cable weights and voltage drop may become critical. It is very easy to come up with the solution of the increase of voltage. However, higher voltage will introduce other problems such as the reliability of insulation coordination on the aircraft due to the increased probability of electrical discharge. For aircraft designers, it is very important to understand the rules of insulation coordination on the aircraft including determining clearance and creepage distances, and also have a clear investigation of the phenomena and mechanism of electrical discharges. Past research has identified a number of the concerns of operating electrical systems at higher voltages in an aerospace environment, especially for dimensioning of clearances. However, there is little study on dimensioning of creepage distances and relevantly flashover and electrical tracking on solid insulating material surfaces. This thesis firstly discusses the rules for determining clearances and creepage distances. The experimental validation work was done for breakdown in air gap and on the solid insulating material surfaces under dry condition so that some standard recommended values can be evaluated not only with theoretical values such Paschen's law. Suggestions of application of those standards were provided. Secondly, the complex electrical discharge under wet condition on solid insulating material surfaces was discussed. A mathematical model to predict this type of electrical failure -electrical tracking (the electrical discharges on solid insulation materials which will lead to physical damage in the materials) with the consideration of different environmental conditions including air pressure, ambient temperature, and pollution degrees was developed. A series of electrical tracking tests were carried out on organic materials to find out the mechanism of electrical tracking and validate the finding by the mathematic model. Finite element analysis simulations were also conducted to find out the background thermal transfer mechanism to support our explanation of those phenomena of electrical tracking. Different test techniques have ben developed for specific impact factors. Finally, the suggestions for utilization of the standards and feasible test techniques for electrical tracking under wet conditions were provided.

With the desire for conventional coal-fired power plants to perform flexible operations, the impact of this operation has become important to the field of steam turbine modelling. This study sought to develop a computationally inexpensive turbine model with minimal OEM intervention in order to predict the internal clearances of high-pressure and intermediate-pressure turbines from Eskom's current turbine fleet. The study saw the utilisation of the Nozzle Analogy theory to develop a 1D multistage turbine thermofluid model as well as the development of a representative 1D turbine process model in order to predict the internal temperature gradients promoted within a steam turbine during transient operation. From this model a further 3D FEA turbine model of both the HP and IP turbine units were developed from simple turbine diagrams to apply the predicted temperature boundaries and predict the thermal and structural response of turbine components during transient loading during a full Cold Start procedure. The result of this study was the successful validation of the 1D and 3D Turbine models against plant data from the candidate unit. This was in the form of known process data of unit performance, as well as thermocouple and differential expansion data taken from sensors housed on the turbine unit itself. Through the validation of these parameters, various calibrations techniques were developed over the course of the study with these techniques allowing investigators to gain insight into turbine aging, operator intervention as well as brought turbine component response. The successful establishment of the paired turbine model allowed investigators to evaluate the cold clearances defined during construction and maintenance of these turbine units in industry, which contributes greatly to the availability and efficiency of the unit during these transient operations. Additionally, the establishment of this model allowed for the investigation of the role that start up speed has on turbine component response. This study demonstrated that the development of such a modelling methodology was possible and yielded results with were accurate and insightful in understanding turbine component responses which are otherwise impossible to measure during real-world operation.

A presente dissertação tem como objetivo analisar as permanências e os afastamentos de alunos do Colégio de Aplicação da UFRGS, da turma Alfa - 1/2001, ao longo de sua trajetória escolar entre o Ensino Fundamental e Ensino Médio. Observou-se que um número significativo de alunos dessa turma se transferiu da escola sendo que os motivos que provocaram essas transferências foram reprovação, falta de adaptação à escola e os turnos dobrados. Em consonância com as teorizações dos Estudos Culturais, de inspiração pós-estruturalista, entendo que as permanências ou os afastamentos de alunos não se tratam apenas de um desenrolar natural das circunstâncias da vida de cada aluno, mas estão implicados em processos de in/exclusão que acabam produzindo as possibilidades de permanência de alguns e as transferências de outros alunos. Apoiei-me em conceitos como categoria social aluno e in/exclusão para compreender como se dá a inserção do aluno, ingressante por sorteio público na instituição, e os processos de diferenciação e normalização decorrentes do convívio com as práticas escolares do CAp/UFRGS. Como estratégias metodológicas foram utilizadas entrevistas e questionários com membros da equipe diretiva, professores e alunos da turma Alfa - 1/2001, e análise de documentos da instituição. No que se refere às unidades analíticas, estas se constituíram das problematizações entre os objetivos de formação dos alunos do CAp/UFRGS, constante em documentos e nas narrativas da equipe diretiva, professores e alunos e as novas populações de crianças e jovens que ingressam por sorteio público na instituição. Tendo como base as análises realizadas pode-se afirmar, mesmo que provisoriamente, que no CAp/UFRGS os alunos ingressantes por sorteio público vão, gradativamente, sendo selecionados por critérios relacionados ao desempenho escolar e adaptação às práticas pedagógicas da escola. Acredito que este estudo poderá, além de problematizar as práticas que desencadeiam uma seleção entre os alunos e produzem as possibilidades de permanência e de transferências, auxiliar em discussões para que esta escola, que tem como uma das suas finalidades pensar e criar novas práticas pedagógicas e metodológicas para auxiliar outras redes públicas de ensino, repensar o atendimento a ser prestado aos novos alunos que nesses novos tempos ingressam em suas salas de aula. / This thesis aims to analyze the permanence and clearances Application College students from UFRGS, Alpha I 2001 class along their trajectory between the Primary and Secondary Education. It was observed that a significant number of students in this class has moved the school and that the reasons that caused these transfers were failing, failure to adapt to school and double shifts. In line with the theories of cultural studies, post-structuralist inspiration, I understand that the stays or removals of students are not just a natural course of life circumstances of each student, but are involved in in / exclusion processes that end up producing the remaining opportunities for some and transfers of other students. I leaned on concepts such as social class and student in / exclusion to understand how is the introduction of students, undergraduate students by public lottery in the institution and the differentiation and standardization processes resulting from the interaction with school practices CAp / UFRGS. As methodological strategies were used interviews and questionnaires with members of the management team, teachers and students of the Alfa class I in 2001, and analysis of the institution's documents. With regard to analytical units in these consisted of problematizations between training objectives of the CAp / UFRGS students, constant in documents and narratives of the management team, teachers and students and new populations of children and young people entering by public lottery the institution. Based on the analyzes it can be stated, however temporary that in CAp / UFRGS commencing students by public lottery will gradually being selected by criteria related to school performance and adaptation to school pedagogical practices. I believe this study may, in addition to questioning the practices that trigger a selection among students and produce the possibility of staying permanently and transfers, assist in discussions to this school, which has as one of its purposes think and create new teaching practices and methodological to help other public schools, rethink the assistance to be provided to new students who enter these new times in their classrooms.