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  • 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.
91

Desenvolvimento de uma metodologia de avaliação de medidores portáteis de radiação em altas taxas de kerma no ar / Development of a methodology of portable radiation meters at high rates of air

DAMATTO, WILLIAN B. 08 April 2016 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-04-08T12:38:10Z No. of bitstreams: 0 / Made available in DSpace on 2016-04-08T12:38:10Z (GMT). No. of bitstreams: 0 / Uma série de testes foi aplicada a medidores portáteis de radiação ionizante para altas taxas de kerma no ar, especificamente medidores do tipo teletector. Estes detectores são do tipo Geiger Müller e são utilizados em rotinas de proteção radiológica em aceleradores, reatores, fontes de alta atividade e ainda em situações de emergência no Brasil, assim como em outros países. Também são encaminhados para calibração no Instituto de Pesquisa Energéticas e Nucleares (IPEN) e foram analisados para estabelecer parâmetros de comportamento destes detectores, especificando as suas sensibilidades e suas características operacionais. Foram realizados testes de variação da leitura dos equipamentos com a tensão da bateria, efeito de geotropismo, dependência energética, dependência angular. Com este testes foi possível determinar as características mais comuns e importantes destes equipamentos permitindo a elaboração de um programa de controle de qualidade. Foram calibrados 17 teletectors durante este trabalho e destes, 10 foram testados. Os testes foram realizados para caracterizar o sis tema gama de irradiação (dosimetria de feixe de radiação) que possui maior atividade e permite testes em medidores do tipo teletectors em uma maior faixa de medição. Desse modo foi feito o aperfeiçoamento do programa de controle de qualidade de medidores portáteis de radiação ionizante para altas taxas de kerma no ar no LCI, oque beneficiou os usuários deste tipo de equipamento, e ainda com medições e calibrações mais consistentes e com melhor controle de qualidade dos processos. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
92

Desenvolvimento de uma metodologia de calibração "in situ" de medidores de atividade / Development of an "in situ" calibration methodology to activity meters

KUAHARA, LILIAN T. 23 November 2017 (has links)
Submitted by Pedro Silva Filho (pfsilva@ipen.br) on 2017-11-23T10:55:22Z No. of bitstreams: 0 / Made available in DSpace on 2017-11-23T10:55:22Z (GMT). No. of bitstreams: 0 / O desempenho de uma prática segura e eficiente de um serviço de medicina nuclear depende, entre outros fatores, de um programa de controle de qualidade completo, principalmente em se tratando dos instrumentos medidores de atividade dos radionuclídeos, os ativímetros. Um programa de controle de qualidade completo deve incluir a calibração de todos os instrumentos de medição utilizados no procedimento. No entanto, no Brasil, a atual norma que estabelece os requisitos de proteção radiológica para serviços de medicina nuclear (SMN), não inclui, ainda, a calibração do ativímetro. Considerando que estes instrumentos, por diversas razões, são de difícil remoção para envio a um serviço de calibração, o propósito deste trabalho foi desenvolver uma metodologia de calibração de medidores de atividades que possa ser aplicada \"in situ\", para o principal radiofármaco utilizado atualmente, o 99mTc. Foram definidos os parâmetros de influência que devem ser levados em conta durante a calibração, assim como uma logística de transporte dos radiofármacos. Um programa de controle de qualidade foi aplicado aos ativímetros do Laboratório de Calibração de Instrumento (LCI). Neste trabalho foram desenvolvidas três metodologias diferentes de calibração, considerando a logística disponível e também a origem da fonte de referência. Na primeira metodologia poderá ser aplicada nos casos em que o LCI envia uma fonte de referência ao SMN. Na segunda o SMN envia uma fonte previamente medida ao LCI que determinará sua atividade real. A terceira metodologia foi aplicada para calibração dos ativímetros pertencentes ao setor de produção de radiofármacos do IPEN. Neste caso a fonte de referência foi enviada ao LCI após uma medição prévia pelo setor de produção. Foi possível aplicar as metodologias em alguns instrumentos pertencentes a clínicas e ao setor de produção. Em todos eles foram encontrados coeficientes de calibração diferentes entre si. A maior variação encontrada foi de 5%, indicando que a medição com este ativímetro está menor em 5% do que é necessário aplicar no paciente. Verificou-se que a troca de recipientes deixa um resíduo que não tem sido considerado nas medições clínicas, podendo acrescentar uma diferença de até 3% nas medições. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
93

Desenvolvimento de equipamento de simulação e calibração para aplicações automotivas embarcadas / Simulation and calibration equipment development for embedded automotive application

Ávila, Paulo Urbano 03 February 2012 (has links)
Orientador: José Antonio Siqueira Dias / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação. / Made available in DSpace on 2018-08-20T01:07:20Z (GMT). No. of bitstreams: 1 Avila_PauloUrbano_M.pdf: 12384470 bytes, checksum: df7ef08ecb3c0ab8dd1f62cc247aeb0a (MD5) Previous issue date: 2012 / Resumo: Apresenta-se a aplicação do projeto metodológico no desenvolvimento de uma maleta para calibração e simulação de sensores em campo (SimuCal®). Este produto passou por todas as etapas do projeto de um produto novo: desenvolvimento, planejamento e aplicação, projeto conceitual e, finalmente, projeto do produto. A metodologia de projeto axiomático foi utilizada para guiar os projetistas pelas distintas fases mencionadas. O sistema foi desenvolvido visando aplicação na área de motores da indústria automotiva. Baseado nas observações coletadas por usuários que testaram o sistema, conclui-se que ele apresenta boa aceitação pelo público-alvo, além de ter custos inferiores aos produtos similares. Para automatizar o processo de medidas, utiliza-se uma placa de condicionamento (PADSi®) para termopar (tipo K) e um transdutor de pressão relativa (Motorola®). Um canal direto do micro controlador recebe e trata o sinal de frequência. O micro-controlador utilizado foi um MSP430 G2231 programado em linguagem C. Os valores recebidos pelo micro-controlador são convertidos, utilizando o módulo de Conversão Analógica Digital (ADC) do microcontrolador, tratados e enviados para o PC através da comunicação serial UART. A conversão AD do sinal é realizada pelo módulo de Conversão AD do microcontrolador da TEXAS MSP 430, com processador RISC de 16 bits. Para o computador, foi desenvolvido um programa usando LabVIEW® ® para: Aquisição dos Dados (via USB), Interface com Usuário (GUI) e Armazenamento de Dados (Datalogger). LabVIEW® é uma linguagem de programação gráfica da empresa National Instruments, com recursos que permitem a criação de interfaces gráficas para usuário (GUI), bem como entrada, saída e armazenamento de dados. O MSP430 G2231 é um micro-controlador com arquitetura Reduced Instructions Set Computing (RISC) com uma arquitetura de barramento clássica Von Neumann (Memória de programa igual à memória de dados). Seus barramentos de Endereço e Dados são de 16 bits / Abstract: An application of a methodological project in the development of a briefcase for calibration and simulation of Field sensors (SimuCal®) is presented. This product underwent of phases of a new product design: development, planning and application, conceptual design and, finally, product design. The axiomatic project design has been used to guide the involved professionals in the various mentioned phases. The system has been developed to be used in the engine area of automotive industry. Based in the collected observations of users who have tested the system, one can conclude that it is well accepted by the target market, having also lower costs than similar products. To automate the measurement process, a conditioning (PADSi®) thermocouple plate (K type) and a relative pressure transduction (Motorola®) are used. A micro-controller direct channel acquires and treats the frequency signal. The micro-controller used was a MSP430 G2231 written in C language. The values received by the micro-controller are converted, using the micro-controller Analog to Digital Conversion module, being then treated and sent to the PC by means of a serial port UART. The AD signal conversion is performed by the TEXAS MSP 430 micro-controller module, with a 16 bits RISC processor. To use in the computer, a software using LabVIEW® was developed for: Data Acquisition (via USB), Graphical User Interface and Data Storage (Datalogger). LabVIEW® is a language for graphical programming developed by National Instruments, with resources for creating Graphical User Interfaces, as well as input, output and storage of data. MSP430 G2231 is a micro-controller using RISC (Reduced Instructions Set Computing) architecture and the classical Von Neumann (program memory equal to data memory) bus architecture. Its addresses and data buses are 16 bits ones / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica
94

Mathematical And Numerical Studies On The Inverse Problems Associated With Propagation Of Field Correlation Through A Scattering Object

Varma, Hari M 02 1900 (has links) (PDF)
This thesis discusses the inverse problem associated with the propagation of field autocorrelation of light through a highly scattering object like tissue. In the first part of the thesis we consider the mathematical issues involved in inverting boundary measurements made from diffuse propagation of light through highly scattering objects for their optical and mechanical properties. We present the convergence analysis of the Gauss-Newton algorithm for the recovery of object properties applicable for both diffuse correlation tomography (DCT) and diffuse optical tomography (DOT). En route to this, we establish the existence of solution and Frechet differentiability of the forward propagation equation. The two cases of the delta source and the Gaussian source illuminations are considered separately and the smoothness of solution of the forward equation in these cases is established. Considering DCT as an example, we establish the feasibility of recovering the particle diffusion coefficient (DB ) through minimizing the data-model mismatch of the field autocorrelation at the boundary using the Gauss-Newton algorithm. Some numerical examples validating the theoretical results are also presented. In the second part of the thesis, we reconstruct optical absorption coefficient, µa, and particle diffusion coefficient, DB , from simulated measurements which are integrals of a quantity computed from the measured intensity and intensity autocorrelation g2(τ ) at the boundary. We also recovered the mean square displacement (MSD) distribution of particles in an inhomogeneous object from the sampled g2(τ ) measured on the boundary. From the MSD, we compute the storage and loss moduli distributions in the object. We have devised computationally easy methods to construct the sensitivity matrices which are used in the iterative reconstruction algorithms for recovering these parameters from these measurements. The results of reconstruction of inhomogeneities in µa, DB , MSD and the visco-elastic parameters, which are presented, show forth reasonably good positional and quantitative accuracy. Finally we introduce a self regularized pseudo-dynamic scheme to solve the above inverse problem, which has certain advantages over the usual minimization method employing a variant of the Newton algorithm. The computational difficulties involved in the inversion of ill-conditioned matrices arising in the nonlinear inverse DCT problem are avoided by introducing artificial dynamics and considering the solution to be the steady-state response (if it exists) of the artificially evolving dynamical system, represented by ordinary differential equations (ODE) in pseudo-time. We show that the asymptotic solution obtained through the pseudo-time marching converges to the optimal solution which minimizes a mean-square error functional, provided the Hessian of the forward equation is positive definite in the neighborhood of this optimal solution. The superior noise tolerance and regularization-insensitive nature of pseudo-dynamic strategy are proven through numerical simulations in the context of DCT.
95

Laser Cooling And Trapping Of Yb Towards High-Precision Measurements

Pandey, Kanhaiya 07 1900 (has links) (PDF)
No description available.
96

Aplikace síťového připojení měřicích přístrojů v technické diagnostice / Network connection application of measurement instruments in technical diagnostics

Gőtz, Lukáš January 2011 (has links)
This labor discusses with the possibilities of using a network connection devices in measurement technology from Agilent. It deals with the theoretical description of the different ways of measuring devices connected to computer networks and their use in laboratory teaching. Practical work is focused on creating automated utilities for selected tasks in the laboratory diagnosis of electrical materials in the software Agilent VEE Pro. The work is a detailed description of the labs in terms of setting and controlling the basic parameters created by the application. Installation and configuration of software and hardware communication tools are summarized in the brochure "How to handle a remote connection of measuring instruments over the Internet."
97

Zařízení pro automatizované testování hardwaru / Automated hardware testing equipment

Macháček, Jan January 2016 (has links)
This thesis is focused on the design of system for automated testing of hardware on Beagle Bone Black platform. The purpose of this thesis is to develop a complex device which will be able to test the functionality of general electronic devices before completion. Use the external measuring devices and design hardware to control them.
98

Konceptutveckling - noggrann inmätning av stansknivar : Concept development - accurate measurement of punch knives

Johansson, Erik January 2023 (has links)
TePe Munhygienprodukter AB paketerar en stor andel av sina produkter (interdentalborstar) i blisterförpackningar. Uppdragsgivaren (TePe) ser möjligheten att förbättra en knivbytesprocess som i nuläget påverkar deras produktion av förpackningar negativt, dessutom lever inte processen upp till företagets värdekedja gällande kvalitet, effektivitet och goda arbetsförhållanden.Studien inleds med informationsinsamling rörande knivbytesprocessen, vidare genereras samt utvärderas möjliga konceptlösningar med syfte att uppnå en högre precision vid inmätning av stansknivar, konceptlösningar som skulle göra processen både snabbare och säkrare. Konceptutvecklingsprocessen mynnar ut i ett konceptuellt mätverktyg som konstrueras och simuleras i CAD-programmet Solidworks (Computer aided design). Slutligen tas tillverkningsunderlag fram i form av ritningar. Dessa ritningar kontrolleras av handledaren på TePe för att säkerställa att kraven och önskemålen som ställs på mätverktyget teoretiskt uppfylls.Rekommendationer vid fortsatt arbete är omkonstruktioner av de resterande stansknivspaketenpå TePe, vilka inte undersökts i denna studie, detta för att medge infästning av mätverktyget i även dessa stansknivspaket. När mätverktyget har tillverkats kan funktionstest, dokumentation och utbildning av berörd personal utföras. Utbildningen och dokumentationen är viktig för att uppnå en enhetlig användning av mätverktyget. Syftet med ett enhetligt bruk är att minimera risken för felanvändning som i sin tur kan leda till avvikande mätresultat. / TePe Munhygienprodukter AB packages a large proportion of their products (interdental brushes) in blister packs. The client (TePe) sees the opportunity to improve a knife replacement process that currently affects their production of packaging negatively, in addition, the process does not live up to the company's value chain in terms of quality, efficiency and good working conditions.The study begins with information gathering regarding the knife replacement process, further possible concept solutions are generated and evaluated with the aim of achieving a higher precision when measuring punch knives, concept solutions that would make the process both faster and safer. The concept development process culminates in a conceptual measurement tool that is constructed and simulated in the CAD program Solidworks (Computer aided design). Finally, manufacturing documents are produced in the form of drawings. Thesedrawings are controlled by the supervisor at TePe to ensure that the requirements and wishes set for the measuring tool are theoretically fulfilled.Recommendations for further work are reconstructions of the remaining punch knife packages on TePe, which were not investigated in this study, this to allow attachment of the measuring tool in these punch knife packages as well. Once the measuring tool has been manufactured, functional testing, documentation and training of affected personnel can be carried out. The training and documentation is important to achieve uniform use of the measuring tool. The purpose of uniform use is to minimize the risk of incorrect use, which in turn can lead to deviating measurement results
99

A study of thermographic phosphor thermometry in an operating turbofan engine

Andersen, Ted Thanning 13 February 2009 (has links)
A new method of remote thermometry utilizing the temperature dependent optical properties of thermographic phosphors was evaluated for use in measuring high-pressure turbine blade metal temperatures in an operating turbofan engine test rig. Thermographic phosphors, ceramics doped with a rare earth metal, were bonded to the turbine blades. These phosphors exhibit fluorescence when optically excited by a laser, and both the intensity and the rate of decay of the fluorescence are temperature dependent An optical fiber probe was used to carry the excitation laser light to the blade surface, and to receive the resulting fluorescence. The blades rotated at speeds up to 30,000 rpm. Synchronization was achieved by a digital pattern recognition circuit, capable of locating a specific blade with each revolution. The investigation concentrated on thennographic phosphor characteristics, phosphor binding methods, and probe optical efficiency. Although poor performance of the selected phosphor binding methods impeded the location of the fluorescence signal in the operating gas turbine engine, many operating characteristics of the technique were determined, and the new measurement technique was established as a promising candidate for further research in the temperature measurement of rotating surfaces inside a turbine engine. / Master of Science
100

Simultaneous measurement of strain and temperature using liquid core optical fiber sensors

De Vries, Marten J. 04 March 2009 (has links)
A liquid core fiber sensor can be used to sense both strain and temperature simultaneously. This liquid core fiber sensor is comprised of a hollow core optical fiber filled with a liquid of a known index of refraction which is slightly higher than that of the silica tube which acts as the cladding. The refractive index fluid is chosen such that the variation of its refractive index with strain and temperature is well defined and linear in the desired range of operation. The core of the sensing fiber contains a fluid which has a thermo-optic coefficient much larger in magnitude (-4.0x10⁻⁴/°C) than that of the silica cladding. This causes the fiber to be more sensitive to temperature changes than all-silica fibers. Both transmitted optical signal intensity and time-of-flight depend strongly on applied strain and temperature. Furthermore, the relative difference between the core and cladding refractive indices changes as a function of both parameters due to the inherently different material types used in the fiber construction. This results in critical strain and temperature regimes within which the refractive index difference is very small, and sensitivity is optimized. Testing of prototype sensors demonstrates these characteristics. A 0.47 m long liquid core fiber containing a liquid with a room temperature refractive index of 1.492 was analyzed. Both time- and intensity-domain behaviors around the device's critical temperature (95°C) confirm theoretical expectations. Simultaneous strain and temperature measurements were performed between 95 °C and 105 °C. Methods for multiplexing liquid core fibers for increasing the range of temperatures that can be monitored were also investigated as well as using those liquid core fibers for cooling purposes. / Master of Science

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