• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 7
  • 2
  • Tagged with
  • 18
  • 18
  • 7
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Proposta e validação de uma nova metodologia para medição automatizada de folgas de trabalho em sistemas de direção automotiva

Aimi, Vinícius January 2010 (has links)
Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.
2

Proposta e validação de uma nova metodologia para medição automatizada de folgas de trabalho em sistemas de direção automotiva

Aimi, Vinícius January 2010 (has links)
Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.
3

Proposta e validação de uma nova metodologia para medição automatizada de folgas de trabalho em sistemas de direção automotiva

Aimi, Vinícius January 2010 (has links)
Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.
4

Indirect Measures as Predictors of Social Skills Observed through Means of Direct Observation

Sidwell, MacKenzie Denise 11 August 2017 (has links)
The scope of the current study focuses on the relationship between direct and indirect methods of measuring social skills in children. Participants included 33 children between the ages of 6 and 11 years old. The sample drew from elementary schools in 2 Southern states in the U.S., as well as social skills groups from a university-based clinic. While some participants had been previously identified has having disabilities impacting social performance, it was not an inclusionary requirement and the majority of children were not identified as having a disability clinically or through a special education eligibility domain. Teachers and clinicians leading social skills groups completed indirect measures, the Behavior Assessment Scale for Children Third Edition (BASC-3) and the Social Skills Improvement System (SSIS) related to the participants’ social skills. Direct observations of participants were completed using the Social Observation System (SOS) by graduate level research assistants. Hierarchical multiple regression analyses were conducted to determine the predictive value of the teacher informed indirect measures on the direct method of observation. Additionally, simple linear regression analyses were conducted to examine the reverse relationship of the direct observation’s ability to predict the variance observed in each indirect measure. Results indicated that both the indirect and direct methods of social skills assessment can significantly predict the other. However, while significant, a low to moderate amount of variance in the direct measure is explained by the indirect measures of social skills. The results and implications of the finding are discussed, as well as limitations and future directions.
5

Přesnost stanovení viskozity kapalin / Accuracy of the determination of liquid viscosity

Zikmund, Ondřej January 2013 (has links)
This master thesis is focused on the rheological properties of liquids, especially on the viscosity and the standard uncertainty. It explains methods of the viscosity measurement and the calibration selected viscometers, the principle of the determination of standard uncertainty by indirect measurement of the viscosity and the density. The main object of this thesis was to create a specialized centre for viscosity measurement and to create a document which could be used by teaching of diagnostics.
6

Kalibrace závaží a vah / Calibration of weights and balances

Vojtová, Klára January 2013 (has links)
In the introductory chapter of this work is caught organizational structure of the national metrology system in the Czech Republic and its links to international organizations. There is indicated the basic terminology of metrology, particularly in the area of classification instruments. The following sections approaching the issue of measurement uncertainties, their classification, sources of uncertainty determined by the type A and B, their specifics and calculation. The above linked area already dealing with themselves calibrations, first of all calibration weights, classification of weights according accuracy classes, established procedures, and finally determining uncertainty in calibration weights. Then, immediately followed by a chapter dealing with calibration balances, performed tests and measurement uncertainties. The main part is of course directed towards the application of acquired knowledge to practical examples, thus performing the calibration weight class F2 using a high-precision weights, both in the premises of the Technical University in Brno, both in the laboratory weighing the Czech Metrological Institute. Further calibration was performed school balances Ohaus Explorer EX224.
7

Exploring the Possibilities and Boundaries of the IPANAT: Distinct Emotions and Affect Regulation

Bode, Regina Carolin 27 August 2014 (has links)
This dissertation extends previous work on the Positive and Negative Affect Test (IPANAT), a test that was developed to measure affective processes at an implicit (supposedly automatic, preconscious) level. In particular, the first manuscript that is included in this dissertation demonstrates that the IPANAT picks up on processes resembling counter-regulation (cf. Rothermund, Voss, & Wentura, 2008) after exposure to negatively valenced emotional stimuli. The IPANAT might therefore be a suitable measure of affect regulation in some contexts. Furthermore, the second manuscript introduces a version of the IPANAT that was designed for the measurement of distinct emotions, the IPANAT for distinct emotions (IPANAT-DE). Finally, the third manuscript and an additional supplemental study not yet submitted for publication provide evidence that the subscales of the IPANAT-DE are sensitive to priming with different emotional expressions, and that facial expressions of the same valence but of different distinct emotions trigger emotion specific changes of IPANAT-DE scores. In the last part of this dissertation, the three manuscripts and the supplemental study are discussed with respect to three overarching issues: 1. The kinds of processes that might drive IPANAT scores and whether these processes are indeed influenced by affective experience or whether they are purely cognitive. 2. How IPANAT scores are related to other aspects of affect. 3. How the IPANAT can be adapted to different research questions as well as to applied contexts.
8

Nejistoty měření průtoku páry / Steam Flow Measurement Error Analysis

Barabášová, Iveta January 2017 (has links)
The thesis deals with analysis of measurement uncertainty. The theoretical knowledge presented in opening chapters is applied on indirect steam flow measurement by orifice plate. Calculation of steam flow is based on knowledge of pressure difference value, static pressure value and temperature. The data are acquired by experimental measurement in laboratory. The mass flow rate uncertainty is determined by normalized procedure (according to standard ČSN EN ISO 5167) and by detailed error analysis (according to standard ČSN ISO 5168) for comparison. Whole numerical computation employs python programming language in Spyder environment. Other computation result is steam consumption of washing cycle.
9

Nepřímé měření momentu na výstupu převodovky zatěžovacího pohonu / Indirect torque measurement in the output of load drive

Jelének, Marek January 2018 (has links)
For loading of excavator drive units, it is necessary to use electromechanical loads with a high torque up to 16,000 Nm in a low speed range from 0 to 150 min-1 with a maximum output of 50 kW. The electromechanical load consists of an asynchronous dynamometer assembly with a tilting torque measurement system in conjunction with a front three-speed gearbox. The dynamometer is powered by a converter with vector control. To determine the torque at the gearbox output, a correction must be made and the influence of operating temperature and operating speed must be taken into account. Experimental measurement of these influences and dependencies makes it possible to create a mathematical model that can be implemented in the power converter for torque control at the output of the gearbox. The aim of the master thesis is a brief design of the loading drive, design an implementation of experimental measurement of efficiency maps and evaluation of the influence of inefficiency of gearbox efficiency.
10

Analýza nejistot nepřímých měření / Uncertainties Analyze of Indirect Measurement

Fišr, Petr January 2010 (has links)
This diploma thesis is engaged with problems of expressing measurement uncertainty especially for indirect measurements. This issue is shown here on a few simple examples. Part of this work is a calculation module for the determination of measurement uncertainties, applied to the role of the laboratory 'measurement of the flow orifice.

Page generated in 0.0799 seconds