Dissertations / Theses on the topic 'Resistance measurement method'

A superconducting niobium triaxial cavity has been designed and fabricated to study residual surface resistance of planar superconducting materials. Unlike many other structures where the test samples are placed in strong magnetic field positions, the edge of a 25.4 mm or larger diameter sample in the triaxial cavity is located outside the strong field region. Therefore, the edge effects and possible losses between the thin film and the substrate have been minimized in this design, ensuring that the induced RF losses are intrinsic to the test material. The fundamental resonant frequency of the cavity is 1.5 GHz, the same as the working frequency of CEBAF cavities. The cavity has a compact size compared to its TE₀₁₁ counterpart, which makes it more sensitive to the sample's loss.
Ph. D.

The International Organization for Standardization (ISO) provides no vibration-based sound power measurement standard that provides Precision (Grade 1) results. Current standards that provide Precision (Grade 1) results require known acoustic environments or complex setups. This thesis details the Vibration Based Radiation Mode (VBRM) method as one approach that could potentially be used to develop a Precision (Grade 1) standard. The VBRM method uses measured surface velocities of a structure and combines them with the radiation resistance matrix to calculate sound power. In this thesis the VBRM method is used to measure the sound power of a single-plate and multiple plate system. The results are compared to sound power measurements using ISO 3741 and good alignment between the 200 Hz and 4 kHz one-third octave band is shown. It also shows that in the case of two plates separated by a distance and driven with uncorrelated sources, the contribution to sound power of each individual plate can be calculated while they are simultaneously excited. The VBRM method is then extended to account for acoustically radiating cylindrical geometries. The mathematical formulations of the radiation resistance matrix and the accompanying acoustic radiation modes of a baffled cylinder are developed. Numberical sound power calculations using the VBRM method and a boundary element method (BEM) are compared and show good alignment. Experimental surface velocity measurements of a cylinder are taken using a scanning laser Doppler vibrometer (SLDV) and the VBRM method is used to calculate the sound power of a cylinder experimentally. The results are compared to sound power measurements taken using ISO 3741.

Developpement d'dune methode de mesure de resistance thermique de contact dans des doubles tubes metalliques minces destines a la fabrication de condenseurs pour des installations nucleaire. La methode, qui fonctionne en regime instationnaire, est basee sur l'analyse de la reponse de l'echantillon a une sollicitation thermique du type echelon temperature

The diploma thesis is focused on the issue of measuring the moisture content in building materials using indirect methods that allow its long-term measurement. The theoretical part of the thesis provides an overview of the forms of moisture in porous building materials and provide an overview of the principles of measuring moisture content. In the experimental part of the thesis, the aim is to verify the available methods for long-term monitoring of moisture in building materials built into building structures. Proven methods of measuring humidity include resistance, capacitive and microwave methods and their comparison with the results of gravimetric measurements. At the end of the work is an evaluation of knowledge and recommendations for further research in this area.

This diploma thesis deals with research and study of soil impedance measurement and soil resistivity. Currently, the issue of measuring and determining soil resistance is ensured through the gradual measurement of certain soil parameters at individual points of the surface (or depth of the ground). This thesis focuses on the idea of measuring soil resistance on a certain area using a network of electrodes through a suitably designed test, measurement and evaluation system. Such an approach may find application in the need to determine soil parameters (such as resistivity) on a specific demarcated area (or depth). The prospect of such an application can be seen in saving time, energy and money needed to measure the soil resistivity of a certain area (as opposed to gradual point measurements). The configuration possibilities of OMICRON CPC 100 measuring instrument were used for the design and implementation of the measuring system for the mentioned purpose. The work is completed by verification of the proposed solution by real measurement with evaluation of the results.

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The main aim of this work is to apply the finite element method (FEM), modeled in short circuit current conduction problems at industrial frequency, calculating grounding resistance and verifying whether a particular project is within the safety specifications. The work optimization techniques for soil modeling are used and the FEM is applied as a way to aid substation commissioning, simulating the Fall of Potential method (FOP) as well as step and touch potential experimenting. The research presents the optimal model of soil found by the minimization of the error between the apparent resistivity curve extracted from electrical soil resistivity measurements. The method of Wenner and a theoretical curve of apparent resistivity for a model of "N" horizontal layers is used as well as the algorithm Particle Swarm Optimization (PSO); a fairly consolidated optimization, a metaheuristic, which recorded an excellent performance when applied to a solution of this problem. Various soil stratification were performed using optimization techniques, and the results of case studies that use graph method, extracted from literature were confronted with this method. The model of grounding problems using the FEM was presented as an alternative solution to the project using the IEEE Std 80, being possible to determine the spatial distribution of the electric potential at all points of the soil, which was modeled as heterogeneous, so getting to know the regions of the project which have the highest potential levels of step and touch. The FEM was also applied to determine the exact location of potential probe in the ground resistance measurement test which was validated through field experiments and through results extracted from literature. The method was also applied to the determination of the potential levels of step and touch existing in a substation, being the testing simulated and proven through field experiments.
Este trabalho tem como objetivo principal, aplicar o mÃtodo dos elementos finitos (FEM), modelados em problemas de conduÃÃo de corrente de curto-circuito à frequÃncia industrial, calculando a resistÃncia de aterramento e verificando se um determinado projeto està dentro das especificaÃÃes de seguranÃa. SÃo utilizadas tÃcnicas de otimizaÃÃo para a modelagem do solo e aplicado o FEM como forma de auxÃlio ao comissionamento de subestaÃÃes, simulando o mÃtodo da queda de potencial e ensaios de potenciais de passo e de toque. à apresentado o modelo Ãtimo do solo, encontrado atravÃs da minimizaÃÃo do erro entre a curva de resistividade aparente extraÃda de mediÃÃes de resistividade elÃtrica do solo atravÃs do mÃtodo de Wenner e uma curva de resistividade aparente teÃrica para um modelo de âNâ camadas horizontais. O referido modelo utiliza o algoritmo Particle Swarm Optimization (PSO), uma metaheurÃstica de otimizaÃÃo bastante consolidada e que apresenta uma excelente performance quando aplicada à resoluÃÃo deste problema. Foram realizadas diversas estratificaÃÃes do solo utilizando tÃcnicas de otimizaÃÃo. Quanto ao resultado de estudos de caso foram utilizados mÃtodos grÃficos extraÃdos da literatura e confrontados com este mÃtodo. O modelo de problemas de aterramento utilizando o FEM foi apresentado como soluÃÃo alternativa ao projeto utilizando a norma IEEE Std 80, sendo possÃvel determinar a distribuiÃÃo espacial do potencial elÃtrico em todos os pontos do solo, que foi modelado como heterogÃneo, conhecendo-se assim as regiÃes do projeto que possuem os maiores nÃveis de potenciais de passo e de toque. O FEM tambÃm foi aplicado na determinaÃÃo da localizaÃÃo exata da sonda de potencial no ensaio de mediÃÃo de resistÃncia de aterramento, sendo validado atravÃs de ensaios de campo e atravÃs de resultados extraÃdos da literatura. O referido mÃtodo tambÃm foi aplicado na determinaÃÃo dos nÃveis de potencias de passo e de toque existentes em uma subestaÃÃo, sendo os ensaios simulados e comprovados atravÃs de experimentos de campo.

Etude de la determination des parametres caracterisant une photopile afin de proposer des methodes pratiques de mesure et d'en fixer les limites d'utilisation. Toutes les methodes connues pour mesurer la resistance serie d'une cellule ont ete utilisees et on montre que les ecarts importants observes proviennent de l'absence d'un controle precis de la temperature. On montre la necessite de determiner, ensemble le facteur de qualite et le courant inverse des cellules. Determination de la variation des parametres avec la temperature les mecanismes de transport des changes sont alors consideres

My diploma thesis deals with a specific dynamic model of DC motor with the parameters obtained from the calculation and from the program using the finite element method. It shows how much accurate results can be achieved in the model, if you use only the values which can be measured, recorded and calculated on the engine. This thesis contens three parts. First part describes the structure and function of DC motor and the basic principle and the use of FEM. Next is calculation analytical and numerical parameters. The search parameters include torque, resistance and inductance of armature winding, resistance and inductance of excitation windings. The last part is dedicated to creating a dynamic model. Results from the dynamic model and measured values are compared in the conclusion of my thesis.

This thesis has evaluated how electrical surface resistance can be measured on conductive coated textiles using two different probes. The electrical surface resistance is a measurement for how difficult it is for current to flow through a material. For textiles, the surface resistance can be measured using four metallic plates, that measure the difference between current supply and voltage drop, this method is called a linear four-point probe.   There is no standard method for measuring the electrical surface resistance on conductive textiles. Therefore, it is not possible to compare textiles made by different producers. It is also not possible to decide what the true resistance is and as conductive textiles are becoming more popular to use, this has started to become a problem in the industry.   Two probes with electrodes of different dimensions were used to evaluate how different electrodes would affect the measured resistance. Measurements were conducted on conductive coated textiles with varying parameters, like coating thickness, sample size and textile construction, to show how the electrical resistance properties differ depending on what probe was used.   It was found that in contrast to other research on conductive textiles and collinear four-point probes, the probes used in this study could detect electrical anisotropic properties. The resistance was different depending on what angle it was measured in. This was found for both a thicker coating and a thinner one. It was also found that the probes could detect a correlation between the angular resistance and the textile construction used.   By measuring the resistance on small samples with the same dimension as the probes electrodes, the resistance was increased compared to when measurements were conducted on samples with dimensions significantly larger than the probes.   Furthermore, the results showed that increasing the distance between the inner electrodes of the probe decreased the measured resistance for both large and small samples. Additionally, it was found that by increasing the width of the outer electrodes the resistance was decreased, an increase in outer electrode width also made it easier to detect electrical anisotropic properties.

This thesis is focused on the description of the method of reactive sputtering of thin films. Currently, there are many ways how to create thin films and there are many applications of thin films in various industrial sectors. In this paper at the first are listed the issue of thin films, followed by an overview of the deposition techniques and of the chemical analysis of deposited thin films. It also describes the four-point measurement method of sheet resistance, mechanical test of adhesion and optical properties. At the end of the theoretical part are described the material composition of the deposited films. The goal of the practical part is to optimize the deposition process of the mixed layer of indium tin oxide (In2O3: SnO2) and contribute to the overall understanding of the influence of annealing on the layer. There were created six series of samples with that applied layers. First, the work focused on examining of the influence of annealing on the throughput in the whole measuring range, and then comparing the series due to the transmittance in the visible light spectrum. Furthermore were compared the value of sheet resistance of unannealed and subsequently annealed samples.

Les travaux présentés ici concernent les échanges de chaleur entre une tôle métallique et un moule en béton réfractaire ou en acier inoxydable sont abordés pour des températures comprises entre 600 et 1000°C, voire plus. Ces échanges sont décomposés en deux étapes : une phase d’approche sans contact dite radiative qui nécessite la détermination des propriétés radiatives des solides en présence puis une phase avec contact : détermination d’une Résistance Thermique de Contact (ou « RTC ») à haute température. Pour décrire ces deux étapes, deux nouveaux moyens expérimentaux ont été étudiés et développés :a) Un banc de mesure directe de l’émissivité à chaud a été développé afin d’étudier la phase sans contact. Une enceinte elliptique utilisant le principe d’un four à images a permis d’obtenir des températures élevées (jusqu’à 1250°C) ainsi que des vitesses de chauffe élevées (>11°C/s) sur les échantillons à caractériser. Une instrumentation permettant de réaliser des mesures d’émissivité spectrale et totale a également été développée. La méthodologie de mesure a été validée en choisissant le platine comme matériau de référence, de par sa bonne stabilité chimique, la faible dépendance de ses propriétés avec la température et des propriétés bien documentées. L’émissivité du TA6V et de l’Inconel 625 en fonction de la température ([600 ; 1000]°C) et du temps de chauffage (jusqu’à 5 heures) a ensuite été étudiée. b) Le développement d’un banc de mesure de la RTC à haute température a permis quant à lui d’étudier la phase avec contact. Ce moyen a pour objectif de mesurer la RTC entre des couples de matériaux métal/métal (TA6V ou Inconel 625 /Inox 310) ou métal/céramique (TA6V ou Inconel 625 /Béton réfractaire) pour des pressions allant jusqu’à 4MPa. L’approche adoptée a été de disposer une pastille métallique représentant la tôle (TA6V ou Inconel 625) entre deux barreaux représentant l’outil (Inox 310 ou béton réfractaire), eux-mêmes, amarrés à une machine de traction. Le chauffage a été réalisé en introduisant le barreau supérieur dans un four résistif porté à 1000°C maximum. L’instrumentation du barreau inférieur a permis de déterminer le flux de chaleur conductif traversant ainsi que sa température de surface, ce qui a permis de mesurer la RTC sur une gamme thermique comprise entre 450 et 800°C et une gamme de pression de contact comprise entre 0,1 et 4MPa. Les résultats obtenus à l’aide de ces deux bancs peuvent être intégrés dans des simulations numériques de formage, pour calculer des recettes de lampes. Ces valeurs ont conduit au formage réussi de de 4 tôles successives en TA6V avec de bonnes conformités géométriques et microstructurales
The present work deals with the high temperature heat transfers involved in sheet/die contact within hot forming processes. The investigated heat ranges lie between 600°C and 1000°C while the study materials are namely TA6V and Inconel 625 (for the sheet) and AISI 310 stainless steel and refractory concrete (for the die). Under such industrial configuration, the heat transfers can be split in two steps: i) a gap closing phase during which the radiative property of the contact pair prevail and ii) a solid contact phase during which the conductive properties are involved and more precisely the thermal contact resistance (TCR). This twostep approach allows a separate investigation of both phenomena which are herein studied by the mean of two dedicated experimental means: a) The gap closing phase is studied through an emissivity measurement setup dedicated to high temperature. The chosen setup is inspired from elliptical oven setups. Its features include a heating rate over 11°C/s and a maximal in-service temperature of 1250°C. The related measurement instruments selection and design are also part of the presented work. The metrological aspects along with the uncertainty quantification are performed through the use of a reference material: pure platinum. This latter has proven worthy by its ability to sustain very high temperature while remaining free from oxidation. In addition, platinum’s optical properties are well documented throughout the scientific literature which provides solid comparisons with other published results. Finally, the construction of an emissivity database is presented for the two sheet materials of the study: TA6V and INCONEL 625. b) The solid contact phase is studied through a second tailor made experimental setup dedicated to TCR measurements. The proposed features include the ability to study metal contact pair (AISI 310 vs. TA6V/INCONEL 625) or ceramic vs. metal contact (Concrete vs. TA6V/INCONEL 625) for temperature as high as 800°C. The whole setup can be inserted within a classical tensile device in order to load the contact interfaces at stress levels similar to those involved in metal forming processes (here up to 4MPa). In practice, a circular sample cut from the studied sheet metals is clasped in between two cylindrical bars made of AISI 310 or concrete. The upper bar is then heated up by the mean of a resistive oven in order to generate a directional heat flux throughout the material interfaces. A suited measurement instrumentation then allows the assessment of the TRC for each contact pair for temperature ranging from 450°C to 800°C and pressure ranging from 0.1MPa to 4MPa. The results obtained from these two setups have built up a material database that was then use to simulate industrial hot forming operations. The process parameters retrieved from these simulation were used as input in an actual forming process and has led to the successful manufacturing of four parts all of which satisfying the quality requirements in term of geometry and microstructure

This work presents the development of a novel and non-invasive method that measures fluid flow rate and temperature in pipes. While current non-invasive flow meters are able to measure pipe flow rate, they cannot simultaneously measure the internal temperature of the fluid flow, which limits their widespread application. Moreover, devices that are able to determine flow temperature are primarily intrusive and require constant maintenance, which can shut down operation, resulting in downtime and economic loss. Consequently, non-invasive flow rate and temperature measurement systems are becoming increasingly attractive for a variety of operations, including for use in leak detection, energy metering, energy optimization, and oil and gas production, to name a few. In this work, a new solution method and parameter estimation scheme are developed and deployed to non-invasively determine fluid flow rate and temperature in a pipe. This new method is utilized in conjunction with a sensor-based apparatus--"namely, the Combined Heat Flux and Temperature Sensor (CHFT+), which employs simultaneous heat flux and temperature measurements for non-invasive thermal interrogation (NITI). In this work, the CHFT+ sensor embodiment is referred to as the British Thermal Unit (BTU) Meter. The fluid's flow rate and temperature are determined by estimating the fluid's convection heat transfer coefficient and the sensor-pipe thermal contact resistance. The new solution method and parameter estimation scheme were validated using both simulated and experimental data. The experimental data was validated for accuracy using a commercially available FR1118P10 Inline Flowmeter by Sotera Systems (Fort Wayne, IN) and a ThermaGate sensor by ThermaSENSE Corp. (Roanoke, VA). This study's experimental results displayed excellent agreement with values estimated from the aforementioned methods. Once tested in conjunction with the non-invasive BTU Meter, the proposed solution and parameter estimation scheme displayed an excellent level of validity and reliability in the results. Given the proposed BTU Meter's non-invasive design and experimental results, the developed solution and parameter estimation scheme shows promise for use in a variety of different residential, commercial, and industrial applications.
MS

Fuktskador är ett problem som kan uppstå vid byggnation i trä om konstruktionen exponeras för nederbörd under byggtiden. Mätning av fuktkvoter i trä kan utföras med flera olika instrument och metoder. Syftet med arbetet är att studera fuktkvotsförändringar i korslimmade träelement som utsätts för långvarig nederbörd i laborationsmiljö. För att utveckla detta område har Linnéuniversitetet tillsammans med Saab utvecklat ett eget mätinstrument. Instrumentet mäter resistans i trä som jämförs med mätvärden från ett annat instrument vid namn Gigamodule. Det egenutvecklade sensorkortet är fortfarande under utveckling. Förutom i arbetets försöksuppställning testas instrumentet även i en byggnad i Växjö. För kontroll av mätresultat har fler metoder och instrument använts. Två modeller har använts som representerar detalj vid anslutning av väggelement-och mellanbjälklag. Båda modellerna har under lika lång tid varit nedsänkta i vattenbad. Försöksuppställningen har utförts mellan 19:e april och 18:e maj 2018. Mätningar och beräkningar har resulterat i jämförbara resultat. Skillnader i resultat utifrån träets fiberriktning har visats från flera instrument. KL-träelementen har uppvisat en god förmåga att trots höga fuktkvotsvärden torka ut och återgå mot normala värden under mätperioden.
Moisture related damage is an occurring problem in wood-based buildings if the material is exposed to rainfall during construction. Measurement of moisture content can be done with various instruments and methods. The purpose of the thesis is to study change in moisture content in cross-laminated-timber, with prolonged exposure to water in laboratory environment. To advance the field, the Linnaeus University has been developing a measurement instrument of their own in collaboration with the company Saab. The instrument measures electrical resistance in wood where the obtained values will be compared to similar measurements from a product named Gigamodule. The self-developed sensor card is still a product under development. In addition to the lab setting measurements the instrument was also installed in a local building in Växjö. To verify the result from the previously mentioned resistance measurers additional instruments and methods have been utilized. Two separate models have been used to represent the detail of the connection between the wall element and the joist. Both models have been submerged under water for an equal amount of time. The experimental setting took place between the 19th of April to the 18th of May 2018. The measurements and calculations have been resulting in values that can be the subject of internal evaluation. Difference in result based on the direction of the grain have been observed in several measurement methods. The CLT-elements demonstrated good drying properties despite periodically high moisture content and the wood indicate a return towards initial levels of moisture.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.14.02 – електричні станції, мережі і системи. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2017. Дисертація присвячена актуальній науково-практичної проблеми пошуку і розробки нових способів для вимірювання опору ЗП, розробки нових конструкцій ЗП, що дозволяють спростити реконструкцію ПС, а також створення і вдосконалення математичних моделей і програм для розрахунку електричних характеристик ЗП довільних конструкцій. Аналіз результатів обстеження існуючих ЗП ПС, виявив серйозні порушення, які призводять до відхилення параметрів від норми і до необхідності модернізації ЗП ПС. Показано, що модернізація ЗП призводить до відновлення його нормованих параметрів. Розроблено математичні моделі ЗП простих дворівневих конструкцій з горизонтальних або кільцевих електродів. В результаті дослідження електричного поля виявлено, що потенціал на поверхні землі над центром квадратного заземлювача може бути вище, ніж над електродом. Удосконалено математичну модель складного дворівневого ЗП ПС, розроблений метод розрахунку його електричних характеристик. Проведено дослідження впливу глибини закладення сітки верхнього рівня ЗП ПС, товщини шару зволоження, просихання або промерзання ґрунту і конструкції ЗП на його електричні характеристики. Виконано теоретичне обґрунтування методу та розроблено спосіб вимірювання опору ЗП ПС в умовах щільної забудови території. Метод застосуємо при будь-якому характері неоднорідності ґрунту, будь-яких розмірах і конфігурації ЗП і довільному розміщенні вимірювальних електродів без відшукання точки нульового потенціалу. Експериментально досліджені електричні характеристики дворівневого ЗП ПС методом фізичного моделювання в електролітичній ванні. Отримані результати показали хороший збіг з результатами розрахунків.
Dissertation for the degree of Ph.D., specialty 05.14.02 – power stations, networks and systems. – National Technical University "Kharkiv Polytechnic Institute", Kharkov, 2017. The dissertation is devoted to the actual and practical problem of search and development of new methods for measurement of resistance of the grounding devices; developments of new designs of the grounding devices allowing to simplify reconstruction of substations; creation and enhancement of mathematical models and programs for calculation of electric characteristics of the grounding devices of any designs. The analysis of the results of the inspection of existing grounding devices of substations revealed serious violations that lead to deviation of parameters from the norm and to the need for modernization of grounding devices of substations. It is shown that the modernization of grounding devices leads to the restoration of its normalized parameters. Mathematical models of grounding devices of simple two-level structures of horizontal or ring electrodes are developed. As a result of the investigation of the electric field, it is revealed that the potential on the surface of the ground above the center of the square grounding electrode can be higher than above the electrode. The mathematical model of complex two-level grounding devices of substations is enhanced. The method of its electrical characteristics calculating is developed. The influence of the depth of the grid of the upper level of the grounding devices of the substations, the thickness of the humidification layer, the drying or freezing of the soil and the design of the grounding devices on its electrical characteristics was studied. Based on the theoretical substantiation of the method, a technique for measuring the resistance of grounding devices of substations in conditions of dense building of the territory is developed. The method is applicable for any kind of ground heterogeneity, any size and configuration of grounding devices and arbitrary placement of measuring electrodes without finding a zero potential point. Electric characteristics two-level the grounding devices of substations are experimentally researched by method of physical modeling in an electrolytic bathtub. The received results showed good coincidence to results of calculations.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.14.02 – електричні станції, мережі і системи. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2017. Дисертація присвячена актуальній науково-практичної проблеми пошуку і розробки нових способів для вимірювання опору ЗП, розробки нових конструкцій ЗП, що дозволяють спростити реконструкцію ПС, а також створення і вдосконалення математичних моделей і програм для розрахунку електричних характеристик ЗП довільних конструкцій. Аналіз результатів обстеження існуючих ЗП ПС, виявив серйозні порушення, які призводять до відхилення параметрів від норми і до необхідності модернізації ЗП ПС. Показано, що модернізація ЗП призводить до відновлення його нормованих параметрів. Розроблено математичні моделі ЗП простих дворівневих конструкцій з горизонтальних або кільцевих електродів. В результаті дослідження електричного поля виявлено, що потенціал на поверхні землі над центром квадратного заземлювача може бути вище, ніж над електродом. Удосконалено математичну модель складного дворівневого ЗП ПС, розроблений метод розрахунку його електричних характеристик. Проведено дослідження впливу глибини закладення сітки верхнього рівня ЗП ПС, товщини шару зволоження, просихання або промерзання ґрунту і конструкції ЗП на його електричні характеристики. Виконано теоретичне обґрунтування методу та розроблено спосіб вимірювання опору ЗП ПС в умовах щільної забудови території. Метод застосуємо при будь-якому характері неоднорідності ґрунту, будь-яких розмірах і конфігурації ЗП і довільному розміщенні вимірювальних електродів без відшукання точки нульового потенціалу. Експериментально досліджені електричні характеристики дворівневого ЗП ПС методом фізичного моделювання в електролітичній ванні. Отримані результати показали хороший збіг з результатами розрахунків.
Dissertation for the degree of Ph.D., specialty 05.14.02 – power stations, networks and systems. – National Technical University "Kharkiv Polytechnic Institute", Kharkov, 2017. The dissertation is devoted to the actual and practical problem of search and development of new methods for measurement of resistance of the grounding devices; developments of new designs of the grounding devices allowing to simplify reconstruction of substations; creation and enhancement of mathematical models and programs for calculation of electric characteristics of the grounding devices of any designs. The analysis of the results of the inspection of existing grounding devices of substations revealed serious violations that lead to deviation of parameters from the norm and to the need for modernization of grounding devices of substations. It is shown that the modernization of grounding devices leads to the restoration of its normalized parameters. Mathematical models of grounding devices of simple two-level structures of horizontal or ring electrodes are developed. As a result of the investigation of the electric field, it is revealed that the potential on the surface of the ground above the center of the square grounding electrode can be higher than above the electrode. The mathematical model of complex two-level grounding devices of substations is enhanced. The method of its electrical characteristics calculating is developed. The influence of the depth of the grid of the upper level of the grounding devices of the substations, the thickness of the humidification layer, the drying or freezing of the soil and the design of the grounding devices on its electrical characteristics was studied. Based on the theoretical substantiation of the method, a technique for measuring the resistance of grounding devices of substations in conditions of dense building of the territory is developed. The method is applicable for any kind of ground heterogeneity, any size and configuration of grounding devices and arbitrary placement of measuring electrodes without finding a zero potential point. Electric characteristics two-level the grounding devices of substations are experimentally researched by method of physical modeling in an electrolytic bathtub. The received results showed good coincidence to results of calculations.

Les briques de magnésie-spinelle et magnésie-hercynite sont fréquemment utilisées dans les fours rotatifs de cimenterie pour leur tenue aux chocs thermiques venant d’une résistance accrue à la propagation de fissures conférée par leur microstructure. Les réseaux de microfissures résultant du différentiel de dilatation thermique entre la matrice magnésienne et les agrégats de spinelle/hercynite favorisent l'activation de mécanismes dissipatifs d’énergie au sein de la zone d’élaboration de la rupture (FPZ) lors d’un chargement mécanique. Dans cette étude, le comportement à la rupture de matériaux modèles à base de magnésie a été étudié en couplant une méthode de corrélation d'images numériques (2P-DIC) adaptée aux problématiques de fissuration avec l’essai de « Wedge Splitting » (WST). Le couplage judicieux de ces méthodes innovantes a fourni des mesures précises des propriétés de rupture et a mis en évidence des mécanismes de rupture caractéristiques, tels que la bifurcation de fissures. L’étude des relations propriété-microstructure a démontré l’impact des microfissures introduites volontairement au sein du matériau sur le comportement thermomécanique de la magnésie-spinelle et la magnésie-hercynite. Malgré des propriétés élastiques et dilatométriques assez similaires entre les inclusions de spinelle et d’hercynite, des mécanismes de microfissuration différents ont été observés, en particulier pour la magnésie-hercynite. En effet, la diffusion entre la magnésie et l’hercynite pendant le frittage a conduit à la formation de solutions solides de spinelles autour des agrégats d'hercynite. Ces solutions solides ont contribué à leur tour à la création de nombreuses microfissures fines par l’effet d’un différentiel de dilatation thermique avec la magnésie. Initialement présents dans la microstructure, les réseaux de microfissures favorisent l’augmentation de l'énergie de rupture des matériaux modèles pendant le WST. De plus, l’analyse des champs de déformation mesurée par 2P-DIC a révélé d’importantes bifurcation de la fissure principale pour les matériaux magnésie-hercynite. Le couplage de la 2P-DIC avec l’essai du WST a démontré que les réseaux de microfissures favorisaient le développement de la FPZ, qui induisait à son tour une augmentation notable de l’énergie de rupture. Dans une approche affinée des courbes-R, des énergies de rupture effectives ont été calculées à l'aide des longueurs de fissure mesurées par 2P-DIC. Cela a permis d'établir des liens étroits entre le développement de la FPZ et une résistance accrue à la propagation de la fissure. Les tendances observées à température ambiante lors des essais de WST ont été confirmées à l’aide d’essais de cyclage dans un nouveau banc de chocs thermiques
Magnesia-spinel and magnesia-hercynite bricks destined for thermal shock applications in cement rotary kilns often show an enhanced crack propagation resistance due to an engineered microstructure design. In these materials, microcrack networks resulting from the thermal expansion mismatch between magnesia matrix and spinel/hercynite aggregates promote the activation of energy dissipating mechanisms within the so-called Fracture Process Zone (FPZ) during loading. In this research, the fracture behaviour of magnesia-based model materials was investigated by coupling a refined Digital Image Correlation method (2P-DIC) with the Wedge Splitting Test (WST). The coupling of these advanced characterisation methods has proven to be very effective in measuring important fracture parameters accurately and in highlighting characteristic fracture mechanisms, such as crack-branching. The investigation of microstructure-property relationships underlined the impact of thermally induced microcracks on the thermomechanical behaviour of magnesia-spinel and magnesia-hercynite materials. Despite the rather similar elastic and dilatometric properties of spinel and hercynite single constituents, peculiar microcracking patterns were observed, especially in magnesia-hercynite. In fact, extensive diffusion between magnesia and hercynite during sintering led to the formation of spinel solid solutions around hercynite aggregates. As a result of thermal expansion mismatch with magnesia, these solid solutions contributed to creating numerous fine microcracks confined within the diffusion zone. Initially present within the microstructure, microcrack networks promote an increase of the specific fracture energy during WST experiments. Moreover, the analysis of strain fields measured by 2P-DIC revealed extensive crack branching for magnesia-hercynite materials. In essence, 2P-DIC and WST measurements showed that microcrack networks promoted the development of the FPZ, which in turn induced higher fracture energies. In a refined R-curve approach, effective fracture energies were calculated using crack lengths measured by 2P-DIC, which helped establish strong links between FPZ development and an enhanced crack propagation resistance. The tendencies observed at room temperature during WST experiments were confirmed during thermal cycling experiments using a novel thermal shock device

Thesis (Ph.D.)--Cleveland State University, 2008
Abstract. Includes bibliographical references (p. 110-111). Electronic full text release has been delayed at the author's request until December 31, 2010.

This project deals with increasing efficiency of one phase induction motor with permanent split capacitor. We can whole thesis divide into two parts, the first one is basic and the second is interested in analysis and measurement. First part handles with construction of single phase induction motor, explanation of function principle, start and run of motor. Calculating of efficiency including type of losses, which reduce efficiency. Second part concerns analysis losses including moment load characteristic, motor measurement while rotor is locked, with no load operation, measuring mechanical and additional losses. Further there will be measured useful values for creation model for simulation (reactance of windings etc.). Than will be the model created in ANSYS Maxwell with module RMxprt. After analytic calculation in RMxprt and using Finite Element Method (FEM) load characteristics will be compared together. This comparison gives us information about accuracy of model for simulation. Simulation and measurement will be carried out on another engine with high quality ferromagnetic material used for magnetic circuit of motor. Further will be done simulation of motor with modifications shown in previous chapter for high efficiency.

碩士
國立交通大學
機械工程系所
106
The high power dissipation and poor thermal conductivity for AlGaN/GaN HEMT power device can result in a serious self-heating effect on the topside surface due to lateral topologies, which will need a well thermal management. This paper proposes a simple, non-invasive, high repeatability and no restricts by the device package method that can evaluate the static and transient thermal resistance constitution. This method is based on the transient thermal resistance by the measurement of the temperature sensitivity electrical parameter for the AlGaN/GaN HEMT. Nowadays, the most important evaluation criterion of the cooling capacity of the power device is the junction-to-case thermal resistance. This study developed a heating curve to replace the traditional cooling curve of the measurement method can significantly reduce the time required for measurement. Also improved the transient dual interface method (TDIM) from JESD 51-14 standard for less error and high measurement repeatability. The information of the internal structures of the power device is very important for the device development and reliability. This paper propose a new, higher resolution and more accurate method called new network identification by deconvolution(NNID). This method has the ability to evaluate the individual thermal resistance of all the internal structures of the power device, and it is illustrated by a number of examples

碩士
國立中央大學
光電科學與工程學系
102
Measurement of thermal resistance with infrared at steady state is a high adaptive and non-contact measuring method for thermal resistance. However, the graphite layer is convenient for measuring method, but it also brings out a problem that causes the temperature error on the heat source area. Therefore, in this research, finite element analysis (FEA) method is used to discuss temperature error from graphite layer. Accor- ding to definition of thermal resistance, finding the effective cross- sectional area along heat transfer propagation direction and using linear fitting to find a functional form which is used to calculate the highest temperature on the surface of sample. At last, performing experiment confirm simulation result.

碩士
國立虎尾科技大學
機械與機電工程研究所
104
This paper, use the optical multi-beam interference theory to measure oil film thickness, and use the multi-functional potential measured resistance value, explore the relationship between the resistance value of the oil film thickness, carried out by the motor load is applied, whereby the waveform applied to the load, and would like to know the relationship between the dynamic oil film thickness and resistance value , film thickness monitoring precision machinery arising at the time of the operation, in order to facilitate long-term use of mechanical parts and reduce the loss of power and energy generated from the friction. 　　In this study, use the optical interference theory establish a machine to measure the lubricating properties, It sets different slider angles, tangential velocities, load, dynamic load topography parameters to discuss influence of different experimental, and utilizes hydrodynamic lubrication theory to verify its feasibility, after the experiment, in the faster speed the oil film thickness will be larger, the opposite of between the load and oil film thikness, using a resistance measurement of film thickness measurement was higher, the greater the resistance value obtained after explore the relationship between the two regression curve, and get through the regression curve of the relationship between the two, so the impact resistance of the biggest factors for the film thickness, film thickness, the higher the resistance value will be increased. 　　Utilizes dynamic load simulation mechanism consistent film thickness in harsh environments film thickness machine during operation, the experimental verification and Formula Renault, the greater the speed, the faster the film after the degree, load the heavier smaller film thickness, after repeatedly applied load film thickness upward trend, while the greater the speed, the faster rise in amplitude comparison found that the higher the frequency of the appreciation after the film thickness variation converge faster, then slower frequency increased film thickness variation value is less, and the elimination of load and Dynamic load is applied to the film per second rate of change of the high rate of change of the film thickness after the second load is applied.

Finally, the effects of external physical factors, such as temperature and contact force, on BP estimation based on m-NHA, were discussed and verified by experiments. Especially, a computational efficient algorithm was developed based on an optical model for motion resistant BP estimation, as well as the estimation of blood oxygen saturation (SaO2). We first developed an optical model with motion effect based on the photon-diffusion analysis, instead of the Beer-Lambert's law, which generally describes the light absorption but fails to account for light scattering in tissue. Based on the optical model, a novel motion resistant algorithm, minimum correlation discreet saturation transform (MCDST), was proposed for the estimation of arterial BP and SaO 2 as well. The novel algorithm is based on the time and time-delayed independence of the "true" signal and motion noise by use of dual PPGs (pulse oximeter). Experimental results indicate that MCDST has a comparable performance in SaO2 estimation and m-NHA calculation, as compared to another clinically verified motion-resistant algorithm---discreet saturation transform (DST). Most importantly, MCDST is much more computationally efficient than DST, because the former only uses simple linear algebra, while the latter uses the adaptive filter. It indicates that MCDST can reduce the required power consumption and circuit complexity of the implementation. It is vitally important for wearable devices, where the small physical size and long battery life are crucial.
First of all, a modified left-ventricle (LV) arterial coupling model was developed by incorporating a nonlinear pressure dependent compliance and two resistances for valve stenosis. A modified LV-arterial coupling model with pressure dependent compliance and taking into account the hypertensives with valve stenosis is quite necessary for proper description of the BP regulation for hypertensives with mitral and/or aortic stenosis, as well as normal people.
Hypertension is the most common cardiovascular disease and is a major public health problem in both developed and developing countries. As hypertension is often asymptomatic, continuous monitoring of blood pressure (BP) for the initiate treatment before the onset of organ damage is of vital importance for home healthcare. However, most of current BP meters, such as sphygmomanometer, are not suitable for the targeted applications because they provide only intermittent blood pressure readings and may cause circulatory interference with the usage of cuff. Moreover, they are not applicable in mobile environment due to the bulky design and the lack of efficient motion resistant algorithms. The objective of this research is to propose a motion resistant method for noninvasive and continuous BP measurement using dual photoplethysmograms (PPG), which could be potentially embedded in the portable or wearable devices for long term BP monitoring.
In summary, the research in this thesis not only covers the fundamental work, such as the modification of heart-arterial system coupling model and the proposal of a novel signal processing method MCDST, but also includes the practical techniques for the estimation of arterial BP as well as oxygen saturation. Expectations for further studies are suggested at the end of this thesis.
Secondly, based on the modified model, a novel parameter, normalized harmonic area (NHA), was proposed for BP estimation by quantifying the frequency distribution in the simulated aortic pressure waveforms. The excellent relationship between NHA and BP was verified by the simulation results. To establish a measurable parameter corresponding to NHA, PPG is investigated because it is widely used for the peripheral circulation monitoring and can be easily obtained at any location on the skin surface. Based on the assumption of quadratic transfer function from aortic pressure to PPG at fingertip, the discreet period transform (DPT) was applied on PPG signal to produce a modified NHA (m-NHA) for BP estimation. For the clinical tests on 85 subjects, the difference between the estimated and the measured blood pressure by m-NHA is 0.97+/-7.9mmHg for systolic blood pressure (SBP) and 0.40+/-4.5mmHg for diastolic blood pressure (DBP), respectively. This result is as good as that (0.73+/-7.6mmHg for SBP, and 0.40+/-4.5mmHg for DBP) from the widely reported pulse transit time (PTT) approach.
Yan Yongsheng.
"November 2005."
Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6561.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.

Wire bonding is the process of creating interconnects between the circuitry on a microchip and PCB boards or substrates so that the microchip can interact with the outside world. The materials and techniques used in this bonding process can cause a wide variation in bond quality, so wire bond reliability testing is very important in determining the quality and longevity of wire bonds. Due to the fact that microchips are encased in protective resins after bonding and their substrates attached to the larger device as a whole, once any single wire bond fails then it could jeapordize the entire device as the wire bonds cannot be individually replaced or fixed. Current methods of reliability testing are lengthy and often destroy the entire sample in the process of evaluation, so the availability of novel non-destructive, real-time monitoring methods as well as accelerated aging could reduce costs and provide realistically timed tests of novel wire bond materials which do not form Intermetallic compounds (IMCs) as rapidly as Au wire on Al substrates. In this thesis, five new chip designs for use in wire bond reliability testing are reported, focusing on the first joint made in a wire bond, called the ball bond. These chips are scaled either to test up to 55 test bonds simultaneously or just one at a time, introducing different requirements for microchip infrastructure capabilities, such as on-chip sensing/data bus, multiplexer, and switches able to operate under High Temperature Storage (HTS) which ranges from temperatures of 150-220 ??C. There are different heating requirements for each of these microchips, needing to be heated externally or containing on-chip microheaters to heat only the ball bond under test, and not the rest of the microchip or surrounding I/O pads. Of the five chip designs, sample chips were produced by an external company. Experimental studies were then carried out with two of these chip designs. They were specifically made to test novel methods of determining ball bond reliability using in-situ, non-destructive sensing, in real-time, while the ball bond undergoes thermal aging. Pad resistance as an analysis tool for ball bond reliability is proposed in this thesis as a new way of evaluating ball bond quality and allows for the testing of electrical connection without the need for specialized measurement probes or difficult bonding processes that contact resistance measurements require. Results are reported for pad resistance measurements of a ball bond under very high temperature storage (VHTS) at 250 ??C, a temperature exceeding typical HTS ranges to accelerate aging. Pad resistance measurements are taken using the four-wire measurement method from each corner of the bond pad, while reversing current direction every measurement to remove thermo-electric effects, and then calculating the average square resistance of the pad from this value. The test ball bond is aged using a novel on-chip microheater which is a N+ doped Si resistive heater located directly underneath the bond pad, and can achieve temperatures up to 300 ??C while not aging any of the I/O pads surrounding it, which are located ~180 ??m away. A 50 ??? resistor is placed 60 ??m away from the heater to monitor the temperature. The use of a microheater allows the aging of novel wire types at temperatures much higher than those permitted for microchip operation while thermally isolating the test bond from the sensing and power bonds, which do not need to be aged. Higher temperatures allow the aging process to be sped up considerably. The microheater is programmatically cycled between 250 ??C (for 45 min) and 25 ??C (for 15 min) for up to 200 h or until the pad resistance measurements fail due breakdown of the bonding pad. Intermetallic compounds forming between the ball bond and the pad first become visible after a few hours, and then the pad becomes almost completely consumed after a day. The pad resistance is measured every few seconds while the sample is at room temperature, and the increase in pad resistance agrees with the fact that Au/Al IMC products are known to have much higher resistance than both pure Au or Al. Also discussed are some aging results of Au wires and Pd coated Cu (PCC) wires bonded to Al bonding pads and aged at a temperature of 200 ??C in an oven for 670 h. The oven aged Au ball bonds also saw IMC formation on the surface of the bonding pad, much like the microheater tests. The PCC ball bonds became heavily oxidized due to lack of Pd on the surface of the ball, the wire portions did not oxidize much. In conclusion, the new structures have been demonstrated to age ball bonds faster than with conventional methods while obtaining non-destructive data. Specifically, the new microheater ages a test bond at an accelerated rate without having an observable effect on the I/O connections used to monitor the test bond. Pad resistance measurements correlate to the aging of the test bond and ensure the electrical integrity of the joint is checked.