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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.
1

The Virginia Tech Calibration System

Fernandez, Javier Oscar 10 June 2011 (has links)
Phasor measurement unit (PMU) applications on power grid monitoring systems have been implemented since the early ninety's. Large monitoring system network performance relies on the consistent measurements of PMUs across the system. This has become a major challenge for designers since large networks use PMUs from various manufacturers who likely implement different synchrophasor technologies to perform the phasor estimations. The current synchrophasor standard, the IEEE C37.118-2005 Synchrophasor Standard, covers adequately the steady-state characterization of PMUs but does not specify transient condition requirements. The North American Synchrophasor Initiative (NASPI) has developed a guide outlining the several tests required for dynamic characterization of PMUs. The National Institute of Standards and Technology (NIST) developed two PMU testing stands for steady-state conformance with the current standard and for dynamic performance testing. Since May 2010, Virginia Tech has been working closely with the NIST in developing a PMU testing system similar to the NIST designs for commercial testing of PMUs and research purposes, the Virginia Tech Calibration System. This thesis focuses on assessing the system accuracy differences between the designs, and the software interface modifications to adapt the new hardware. / Master of Science
2

An Automated Calibration Setup For Laser Beam Positioning Systems In Visual Inspection Applications

Kiraz, Ercan 01 January 2013 (has links) (PDF)
In this study, a calibration setup for laser beam positioning systems used in visual inspection applications in industry is designed and manufactured. The laser positioning systems generate movable parallel laser lines on the projection surface. There are several translational and angular error sources affecting the positioning accuracy of the laser lines on the projection surface. Especially, since the laser line positioning error caused by angular error sources increases with the distance between the laser system and the projection surface, angular parameters of the laser sources should be measured and adjusted precisely. The calibration setup developed in this study detects the laser line positions at two different projection distances by means of laser sensing cameras which are positioned precisely along the laser lines and laser positioning axis which is perpendicular to these lines. Cameras detect the positions of the laser lines which are directed to the camera sensors with micrometer repeatability by means of some special imaging algorithms. The precise positioning of the cameras requires a special camera positioning system. For this reason, the disturbances like temperature changes and vibration should be minimized. In order to provide a suitable environment for the calibration system, special tests are conducted and a special calibration room is constituted. Construction inside the room is also made by considering the required ambient parameters. Finally, several verification tests of the calibration system are conducted.
3

An investigation into improving the repeatability of steady-state measurements from nonlinear systems : methods for measuring repeatable data from steady-state engine tests were evaluated : a comprehensive and novel approach to acquiring high quality steady-state emissions data was developed

Dwyer, Thomas Patrick January 2014 (has links)
The calibration of modern internal combustion engines requires ever improving measurement data quality such that they comply with increasingly stringent emissions legislation. This study establishes methodology and a software tool to improve the quality of steady-state emissions measurements from engine dynamometer tests. Literature shows state of the art instrumentation are necessary to monitor the cycle-by-cycle variations that significantly alter emissions measurements. Test methodologies that consider emissions formation mechanisms invariably focus on thermal transients and preconditioning of internal surfaces. This work sought data quality improvements using three principle approaches. An adapted steady-state identifier to more reliably indicate when the test conditions reached steady-state; engine preconditioning to reduce the influence of the prior day’s operating conditions on the measurements; and test point ordering to reduce measurement deviation. Selection of an improved steady-state indicator was identified using correlations in test data. It was shown by repeating forty steady-state test points that a more robust steady-state indicator has the potential to reduce the measurement deviation of particulate number by 6%, unburned hydrocarbons by 24%, carbon monoxide by 10% and oxides of nitrogen by 29%. The variation of emissions measurements from those normally observed at a repeat baseline test point were significantly influenced by varying the preconditioning power. Preconditioning at the baseline operating condition converged emissions measurements with the mean of those typically observed. Changing the sequence of steady-state test points caused significant differences in the measured engine performance. Examining the causes of measurement deviation allowed an optimised test point sequencing method to be developed. A 30% reduction in measurement deviation of a targeted engine response (particulate number emissions) was obtained using the developed test methodology. This was achieved by selecting an appropriate steady-state indicator and sequencing test points. The benefits of preconditioning were deemed short-lived and impractical to apply in every-day engine testing although the principles were considered when developing the sequencing methodology.
4

Desenvolvimento de um sistema de Calibração assistida por computador Para instrumentos de medição de Temperatura e pressão em estações de Medição de gás natural

Maia, Gerizaldo Cavalcanti Gomes 22 October 2015 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-05-30T14:58:50Z No. of bitstreams: 1 arquivototal.pdf: 2306657 bytes, checksum: f4add77fe1f7de92f01030058ac119dc (MD5) / Made available in DSpace on 2017-05-30T14:58:50Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2306657 bytes, checksum: f4add77fe1f7de92f01030058ac119dc (MD5) Previous issue date: 2015-10-22 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The present work objectives were developing a computer-aided system for pressure and temperature measuring instruments calibration. This system's focus was easing the work of personnel involved in calibration operations in natural gas measuring stations by automatic filling of instruments identification data through automatic selection, being requested to the user only the insertion of measurements obtained by standard instrument and the calibrated instrument throughout the measuring range. The sources of uncertainty type B, obtained from the characteristics of the instruments used during the calibration process and the calibration history are automatically determined from a query to the database. The type B calibration uncertainty, which is the result of combining all the type B uncertainty sources, is combined with the type A uncertainty obtained by statistical analysis of the residuals of the best fit linear function between the measurement instrument to be calibrated and their true conventional values. The final results of the process, which are automatically reported in output calibration report, are the linear coefficients of best fit function and the confidence interval associated with this adjustment, which is combined with the type B uncertainty, related to a confidence level set. Furthermore, other information presented are operating parameters such as calibration date, equipment used, detected nonconformities, among other information stored for further query and analysis. / O presente trabalho visou o desenvolvimento de um sistema de calibração de instrumentos de medição de pressão e temperatura assistida por computador. A utilização deste sistema objetivou facilitar o trabalho do pessoal envolvido nas operações de calibração em estações de medição de gás natural, pois o preenchimento dos dados de identificação dos instrumentos é automático após seleção, sendo solicitado ao usuário apenas a inserção das indicações obtidas pelo instrumento padrão e pelo instrumento calibrado em toda a faixa de medição. As fontes de incerteza do tipo B, obtidas a partir das características dos instrumentos utilizados durante o processo de calibração bem como do histórico de calibração, são automaticamente determinadas a partir da consulta a um banco de dados. A incerteza do tipo B da calibração, que é o resultado da combinação de todas as fontes de incerteza do tipo B obtidas, é combinada com a incerteza do tipo A obtida através da análise estatística dos resíduos da função linear de melhor ajuste entre as indicações do instrumento a ser calibrado e respectivos valores verdadeiros convencionais. Os resultados finais do processo, sintetizados no relatório de calibração emitido automaticamente, são os coeficientes lineares da função de melhor ajuste e o intervalo de confiança associado a este ajuste, sendo este combinado com a incerteza do tipo B, relacionado a um nível de confiança estabelecido. Além das informações estatísticas, são apresentados parâmetros operacionais, tais como data de calibração, equipamentos utilizados, não conformidades detectadas, dentre outros armazenados no banco de dados para consulta e análise posterior.
5

Quadrature Phase-Domain ADPLL with Integrated On-line Amplitude Locked Loop Calibration for 5G Multi-band Applications

Zhang, Xiaomeng 04 May 2022 (has links)
No description available.
6

An Investigation into Improving the Repeatability of Steady- State Measurements from Nonlinear Systems. Methods for measuring repeatable data from steady-state engine tests were evaluated. A comprehensive and novel approach to acquiring high quality steady-state emissions data was developed

Dwyer, Thomas P. January 2014 (has links)
The calibration of modern internal combustion engines requires ever improving measurement data quality such that they comply with increasingly stringent emissions legislation. This study establishes methodology and a software tool to improve the quality of steady-state emissions measurements from engine dynamometer tests. Literature shows state of the art instrumentation are necessary to monitor the cycle-by-cycle variations that significantly alter emissions measurements. Test methodologies that consider emissions formation mechanisms invariably focus on thermal transients and preconditioning of internal surfaces. This work sought data quality improvements using three principle approaches. An adapted steady-state identifier to more reliably indicate when the test conditions reached steady-state; engine preconditioning to reduce the influence of the prior day’s operating conditions on the measurements; and test point ordering to reduce measurement deviation. Selection of an improved steady-state indicator was identified using correlations in test data. It was shown by repeating forty steady-state test points that a more robust steady-state indicator has the potential to reduce the measurement deviation of particulate number by 6%, unburned hydrocarbons by 24%, carbon monoxide by 10% and oxides of nitrogen by 29%. The variation of emissions measurements from those normally observed at a repeat baseline test point were significantly influenced by varying the preconditioning power. Preconditioning at the baseline operating condition converged emissions measurements with the mean of those typically observed. Changing the sequence of steady-state test points caused significant differences in the measured engine performance. Examining the causes of measurement deviation allowed an optimised test point sequencing method to be developed. A 30% reduction in measurement deviation of a targeted engine response (particulate number emissions) was obtained using the developed test methodology. This was achieved by selecting an appropriate steady-state indicator and sequencing test points. The benefits of preconditioning were deemed short-lived and impractical to apply in every-day engine testing although the principles were considered when developing the sequencing methodology.
7

Expérience SuperNEMO : Études des incertitudes systématiques sur la reconstruction de traces et sur l'étalonnage en énergie. Evaluation de la sensibilité de la 0nbb avec émission de Majoron pour le Se-82. / SuperNEMO Experiment : Study of Systematic Uncertainties of Track Reconstruction and Energy Calibration. Evaluation of Sensitivity to 0nbb with Emission of Majoron for Se-82.

Macko, Miroslav 17 December 2018 (has links)
La thèse présentée est composée de divers projets que j’ai réalisés au cours de la phasede construction du démonstrateur SuperNEMO pendant la période 2015-2018.L’expérience SuperNEMO, située dans le laboratoire souterrain LSM, est conçue pourrechercher 0nbb de 82Se. Sa technologie, qui tire parti du suivi des particules, est uniquedans le domaine des expériences de double désintégration bêta. La reconstruction de latopologie des événements est un outil puissant pour la suppression de fond naturel.Une partie de la thèse est consacrée à un travail expérimental. J’ai participé à la préparationde modules optiques, partie intégrante du calorimètre SuperNEMO. Les résultats de lapréparation et des tests de 520 modules optiques sont présentés dans la thèse. En outre, jeprésente les résultats de la cartographie complète des sources 207Bi effectuée à l’aide de pixeldétecteurs. Je présente également des mesures précises de leurs activités pour lesquellesj’ai utilisé des détecteurs HPGe. Ces sources 207Bi seront utilisées pour l’étalonnage ducalorimètre. L’étude a joué un rôle clé dans le choix des 42 sources qui participeront àl’étalonnage du démonstrateur.Une autre partie de la thèse contient des projets axés sur les simulations de Monte Carlo.Dans un premier temps, j’ai étudié la précision de reconstruction de vertex réalisable parun algorithme de reconstruction développé pour l’expérience SuperNEMO. La précision estévaluée à l’aide de différentes méthodes statistiques dans diverses conditions (champ magnétique,énergie des électrons, angles d’émission, etc.). Les facteurs influençant la précision,en fonction des résultats obtenus, sont discutés.En 2018, j’ai également effectué les simulations du blindage contre les neutrons. Différentsmatériaux de blindage d’épaisseurs différentes ont été (dans la simulation) exposés àun spectre de neutrons réaliste provenant du LSM et les flux situés derrière le blindage ont étéestimés. Il a été démontré que les parties du détecteur en fer devraient capturer la grande majoritédes neutrons passant le blindage. Je discute également un problème de simulation desrayonnements gamma de désexcitation après capture de neutrons thermiques, apparaissantdans les logiciels standard. Je propose un nouveau générateur étendu capable de résoudre leproblème et de démontrer le concept dans un exemple analytiquement résolu.Avec le standard 0nbb, SuperNEMO sera capable de rechercher des modes plus exotiquesde la décroissance. Dans cette thèse, je présente les limites de demi-vie possibles queSuperNEMO peut atteindre pour 0nbb avec l’émission d’un ou deux Majorons. L’étudeest réalisée en fonction de l’activité de contamination interne par les isotopes 208Tl et 214Bi.La période de mesure après laquelle SuperNEMO devrait pouvoir améliorer les limites dedemi-vie de NEMO-3 (au cas où la décroissance ne serait pas observée) est estimée. / Presented thesis is composed of variety of projects which I performed within theconstruction phase of SuperNEMO demonstrator during the period 2015-2018.SuperNEMO experiment, located at underground laboratory LSM, is designed to searchfor 0nbb of 82Se. Its technology, which takes advantage of particle tracking, is unique inthe field of double beta decay experiments. Event topology reconstruction is powerful toolfor suppression of naturally-occurring background radiation.Part of the thesis is dedicated to experimental work. I took part in assembly and testingof optical modules - the integral part of SuperNEMO calorimeter. Results of tests afterassembly of 520 optical modules are presented in the thesis. Furthermore, I present resultsof complete mapping of 207Bi sources performed using pixel detectors. I also present precisemeasurements of their activities for which I used HPGe detectors. These 207Bi sources willbe used for calibration of the calorimeter. Study played a key role in choice of 42 sourceswhich were installed in the demonstrator and will take part in calibration of the demonstrator.Another part of the thesis contains projects focused on Monte Carlo simulations. In firstof them, I studied a vertex reconstruction precision achievable by reconstruction algorithmdeveloped for SuperNEMO experiment. Precision is evaluated using different statisticalmethods in variety of different conditions (magnetic field, energy of electrons, angles ofemission, etc.). Factors influencing the precision, based on the achieved results are discussed.In 2018, I also performed simulations of neutron shielding. Variety of shielding materialswith different thicknesses were (in the simulation) exposed to realistic neutron spectrumfrom LSM and the fluxes behind the shielding were estimated. It was shown that the partsof the detector made of Iron should be expected to capture vast majority of neutrons passingthe shielding. I also discuss a problem with simulation of deexcitation gamma radiation,emitted after thermal neutron capture, which arises in standard software packages. I proposednew extended generator capable to resolve the problem and demonstrate the conceptin analytically solvable example.Along with standard 0nbb, SuperNEMO will be capable of searching for more exoticmodes of the decay. In the thesis, I present possible half-life limits achievable by SuperNEMOfor 0nbb with emission of one or two Majorons. The study is performed asa function of activity of internal contamination from 208Tl and 214Bi isotopes. Measurementperiod after which SuperNEMO should be able to improve half-life limits of NEMO-3 (incase the decay would not be observed) are estimated. / Predkladaná dizertaˇcná práca je zložená z projektov rôzneho charakteru, na ktorýchsom pracoval vo fáze výstavby SuperNEMO demonštrátora v období rokov 2015-2018.Experiment SuperNEMO, umiestnený v podzemnom laboratóriu LSM, je zameraný nahl’adanie 0nbb v 82Se. Experiment je založený na technológii rekonštrukcie dráh elektrónovvznikajúcich v rozpade. Tento prístup je jedineˇcný v oblasti 0nbb experimentov.Rekonštrukcia topológie udalostí je silným nástrojom na potlaˇcenie pozad’ovej aktivity vyskytujúcejsa v laboratóriu, ako aj v konštrukˇcných materiáloch detektora.Cˇ ast’ práce je venovaná experimentálnym úlohám. Zúcˇastnil som sa na konštrukciioptických modulov - súˇcasti hlavného kalorimetra. Práca obsahuje výsledky prípravy atestovania 520 optických modulov, a takisto výsledky kompletného mapovania kalibraˇcných207Bi zdrojov vykonaného za pomoci pixelových detektorov. V tejto ˇcasti sú odprezentovanéaj výsledky merania ich aktivít za pomoci HPGe detektorov. Štúdia zohrávala kl’úˇcovúúlohu pri výbere 42 zdrojov, ktoré boli nainštalované do prvého SuperNEMO modulu, dodemonštrátora, a budú použité na jeho energetickú kalibráciu.ˇ Dalšiu ˇcast’ práce tvoria úlohy zamerané na Monte Carlo simulácie. Prvým z nich,je štúdia presnosti rekonštrukcie vertexu dvojitého beta rozpadu. Rozpadové vertexy súrekonštruované tzv. CAT (Cellular Automaton Tracker) algoritmom vyvinutým pre experimentSuperNEMO. V štúdii sú porovnávané viaceré spôsoby definovania presnosti rekonštrukcie.Presnost’ je skúmaná v závislosti na magnetickom poli v detektore, energii elektrónov,uhlov ich emisie atd’. Na základe výsledkov sú v štúdii pomenované faktory, ktoré ovplyvˇnujú presnost’ rekonštrukcie vertexov dvojitého beta rozpadu.V roku 2018 som takisto vypracoval štúdie neutrónového tienenia. Oˇcakávané toky neutrónovza tienením boli odhadnuté pomocou Monte Carlo simulácie. Kvalita odtienenia neutrónovz realistickéh pozad’ového spektra, nameraného v LSM, bola skúmana pre tri rôznemateriály rôznych hrúbok. Výsledky ukázali, že neutrónový tok prechádzajúci tienenímbude primárne zachytávaný na komponentoch detektora zhotoveného zo železa. V rámcištúdie neutrónového tienenia je takisto diskutovaný problém simulácie deexcitaˇcných gamakaskád, produkovaných jadrami, po záchyte termálnych neutrónov. Štandardné simulaˇcnésoftvérové balíˇcky využívajú generátory gama kaskád nepostaˇcujúce pre potreby štúdie.Navrhol som nový generátor, ktorý je schopný tieto problémy vyriešit’. Funkˇcnost’ generátorabola preukázaná na príklade jednoduchého systému.Okrem štandardného 0nbb je SuperNEMO experiment schopný hl’adat’ aj jeho exotickejšieverzie. V práci sa nachádzajú odhady limitov ˇcasu polpremeny 0nbb s emisiou jednéhoalebo dvoch Majorónov, dosiahnutel’né SuperNEMO demonštrátorom. Tieto limity sú študovanév závislosti na aktivite izotopov 208Tl a 214Bi, ktoré kontaminujú zdrojovú 82Se fóliu.Bola odhadnuá doba merania, za ktorú bude SuperNEMO schopný vylepšit’ limity ˇcasu polpremeny,pre dva spomenuté rozpadové módy, dosiahnutých experimentom NEMO-3.
8

Anisotropic Magnetoresistance Magnetometer for inertial navigation systems

Mohamadabadi, Kaveh 29 November 2013 (has links) (PDF)
This work addresses the relevant errors of the anisotropic magnetoresistance sensor for inertial navigation systems. The manuscript provides resulting guidelines and solution for using the AMR sensors in a robust and appropriate way relative to the applications. New methods also are proposed to improve the performance and, reduce the power requirements and cost design of the magnetometer. The new compensation method is proposed by developing an optimization algorithm. The necessity of the sensor calibration is shown and the source of the errors and compensating model are investigated. Two novel methods of indoor calibration are proposed and examples of operating systems are presented.
9

[en] METROLOGICAL EVALUATION OF THE INTERLABORATORIAL COMPARISON OF THE ULTRASONIC FLOW METER CALIBRATION / [pt] AVALIAÇÃO METROLÓGICA DA COMPARAÇÃO INTERLABORATORIAL DA CALIBRAÇÃO DE MEDIDORES ULTRA-SÔNICOS

WALACE FERREIRA DE ARANTES 23 May 2007 (has links)
[pt] O presente trabalho refere-se à avaliação metrológica de um mesmo medidor ultra-sônico de vazão de líquido pelo método de tempo de trânsito, quando instalado em dois sistemas distintos de calibração, pertencentes, respectivamente, a dois laboratórios acreditados, ambos operando em conformidade com as especificações técnicas de instalação do fabricante e segundo os requisitos mínimos especificados em normas e recomendações internacionais. A pesquisa investigou o efeito na calibração introduzido por uma válvula e uma curva longa de 90° instaladas imediatamente à montante do trecho reto de medição, que tem o seu comprimento atendendo as condições mínimas especificadas nas normas aplicáveis. Concluiu-se pela necessidade de se utilizar pelo menos 40 diâmetros nominais (40 DN) de comprimento de trecho reto, para que a influência da presença da válvula e da curva longa possa ser considerada desprezível. O desenvolvimento do presente trabalho foi motivado pela crescente aplicação de medidores ultra-sônicos de vazão na indústria de petróleo e pela urgente necessidade de se contribuir para o avanço do conhecimento desta tecnologia e da normalização aplicável. Nesse sentido, o presente trabalho contribui: (i) para o melhor entendimento da tecnologia de medição e do processo de calibração de medidores ultra-sônicos de vazão de líquidos; (ii) para o avanço da normalização no setor, uma vez que inclui uma análise crítica de requisitos mínimos normalizados; (iii) para aprimoramento dos critérios de acreditação de laboratórios que realizam a calibração de medidores de vazão, já que avaliou desvios de calibração ocorridos em distintas instalações em conformidade com as normas aplicáveis. / [en] This work deals with the metrological evaluation of the same ultrasonic flow meter by the transit time method, when installed in two different calibrating systems, belonging, respectively, to two accredited laboratories, both operating according to the manufacture´s installation technical specification, and following the minimum requirements, as specified in international standards and recommendations. The research investigated the effect in calibration due to the installation of a valve and a long 90° curve, immediately upstream of the measurement test section, with its length dimensioned according to the minimum requirements of the applicable standards. It was concluded that a longer straight sections (at least 40 diameters) should be specified, so that the influence of the installation of the valve and the curve could be neglected. The development of the present work was motivated by the growing utilization of ultrasonic flow meters by the oil industry, and by the urgent need to contribute to the advance of the technology and the applicable standardization. In this aspect, this work contributes to: (i) a better understanding of the measurement technology and of the procedure of ultrasonic liquids flow meters; (ii) the advance of the technology standardization, since it includes a critical analysis of the minimum requirements, as specified by the standards; (iii) improving the laboratory accreditation criteria for flow meter calibration, because the influence of the installation in the calibration was experimentally shown.
10

Testování jednotek Merging Unit v sestavě s proudovými a napěťovými převodníky / Testing of Merging Unit comprising voltage and current transducers in the set

Ziegler, Jiří January 2016 (has links)
The diploma thesis is focused on testing and design of a test system of merging unit which provides digital output according to IEC 61850-9-2. The parameters and distinguishing features of the test system are based on functional principles of merging unit and standards dealing with the testing of transducers. The proposed test system is based on modular PXI Express system from National Instruments. The desing is performed with respect to the possibility of generating test signals and measurements for voltage up to 38.4 kV and current up to 2000 A. The proposed test system meets the criteria for testing transducers of accuracy class up to 0.5. Assuming of calibration designed test system as a whole, this test setup has the potential to meet the technical requirements for testing transducers of accuracy class up to 0.1.

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