Thesis (M.S.)--Rochester Institute of Technology, 2009. / Typescript. Includes bibliographical references.

<p>Glaucoma is the leading cause of irreversible blindness worldwide effecting more than 2.7 million people in the U.S alone. Treatments exist in the form of both pharmaceutical and surgical options, but often do not provide the desired efficacy. For example, the failure rate of a trabeculectomy procedure is 39% within 5 years. Additionally, none of the current glaucoma treatments allow for closed loop monitoring of pressure, therefore requiring more frequent doctor visits. Glaucoma management can be improved through the use of a closed loop application of electroceutical treatment. The goal is to develop an implantable device that will be inserted into the eye to monitor intraocular pressure (IOP) and provide responsive therapeutic stimulation to the eye. I designed a discrete pressure monitoring system that interacts with a bare die piezoresistive pressure sensor. The system is based on a Wheatstone bridge design which translates the input resistances of the pressure sensor into a voltage output. This system has an average accuracy of 0.53 mmHg and draws 295 µW of power. I then combined this pressure system with data processing code and Howland current pump stimulation circuitry. This simulation system can output up to 1.05 mA of current for electroceutical intraocular stimulation to lower IOP. Future work will involve miniaturizing the circuitries in the form of an ASIC and packaging the entire system into an ocular implant. This implant can wirelessly monitor IOP and provide therapeutic stimulation to lower IOP. A reliable, closed loop method of lowering IOP would greatly benefit the ever-growing population affected by glaucoma.</p>

Structural Health Monitoring (SHM) is widely used to monitor the short and long-term behavior of intelligent structures. This monitoring can help prolong the useful service lives and identify deficiencies before possible damage of such structures. The sensing systems that are usually deployed are intended to faithfully relay readings that reflect the true conditions of these structures. Unfortunately, this is seldom the case due to the presence of errors in the collected data. The electrical strain gauges used in SHM environments for instrumentation purposes are susceptible to numerous sources of error. Apparent strain is known to be the most serious of all such errors. However or whichever way temperature variations of the gauge’s environment occurs, apparent strain is introduced. This work focuses on modeling apparent strain in an SHM environment using National Instruments’ (NI) hard and software. The results of this work are applicable for thermal compensation in current test programs.

Structural Health Monitoring (SHM) is widely used to monitor the short and long-term behavior of intelligent structures. This monitoring can help prolong the useful service lives and identify deficiencies before possible damage of such structures. The sensing systems that are usually deployed are intended to faithfully relay readings that reflect the true conditions of these structures. Unfortunately, this is seldom the case due to the presence of errors in the collected data. The electrical strain gauges used in SHM environments for instrumentation purposes are susceptible to numerous sources of error. Apparent strain is known to be the most serious of all such errors. However or whichever way temperature variations of the gauge’s environment occurs, apparent strain is introduced. This work focuses on modeling apparent strain in an SHM environment using National Instruments’ (NI) hard and software. The results of this work are applicable for thermal compensation in current test programs.

Minimizing the need to physically adjust hardware platforms used for sensor measurements during the construction phase of an electric vehicle can be beneficial. Since different sensors have different measuring ranges a hardware platform used for a specific sensor might not work for another one, without physically tampering with it. One way to solve such an issue is to build a general hardware platform that can be adjusted digitally through software to match the range of a variety of sensors. In this thesis, the implementation of a prototype General Purpose Data Acquisition Unit has been investigated. The design consists of a Wheatstone bridge implementation for measurements with resistive sensors, due to its capabilities of accurate detection of small changes in resistance. Digital potentiometers were implemented in the design to add dynamic capabilities for calibration and measurements with different types of resistive sensors through software. The proposed implementation has been tested on a prefboard and built on a Printed Circuit Board. Further testing is required to better specify and evaluate the proposed implementation. / Att minimera behovet av att fysiskt justera hårdvaruplattformar för mätningsprocessorer med sensorer vid tillverkning av en elektriskt driven bil kan vara fördelaktigt. Olika sensorer har olika mätområden och en hårdvaruplattform kan fungera väl för en sensor men inte nödvändigtvis för en annan utan att hårdvaran fysiskt behöver justeras. Ett sätt att lösa detta problem är att utveckla en generell hårdvaruplattform för insamling av data från sensorer som digitalt kan anpassas för att fungera med ett större utbud av sensorer. I denna rapport har en implementering av en generell hårdvaruplattform för datainsamling undersökts. Implementationen består av en konfiguration av en Wheatstone brygga för resisitiva sensorer, på grund av dess förmåga att noggrant mäta små förändringar av resistans. Digitala potentiometrar användes i implementeringen för att ge möjligheten till att dynamiskt kunna kalibrera och mäta data från olika typer av resistiva sensorer genom mjukvara. Den förslagna implementationen har genomfört ett test på en perfboard och monterats på ett kretskort. Fler tester krävs för att bättre kunna specificera och evaluera den förslagna implementationen. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

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Made available in DSpace on 2014-12-17T15:14:51Z (GMT). No. of bitstreams: 1 RobertoTGO_DISSERT.pdf: 394069 bytes, checksum: fbb8faf7e24cc92335302e442b92ec43 (MD5) Previous issue date: 2010-02-22 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work we study the phase transitions of the ferromagnetic three-color Ashkin-Teller Model in the hierarquical lattice generated by the Wheatstone bridge using real space renormalization group approach. With such technique we obtain the phase diagram and its critical points with respective critical exponents v. This model presents four phases: ferromagnetic, paramagnetic and two intermediates. Nine critical points were found, three of which are of Ising model type, three are of four states Potts model type, one is of eight states Potts model type and the last two which do not correspond to any Potts model with integer number of states. iv / Neste trabalho estudamos as transi??es de fase do modelo de Ashkin-Teller de tr?s cores ferromagn?tico na rede hier?rquica ponte de Wheatstone utilizando o m?todo de grupo de renormaliza??o no espa?o real. Com a utiliza??o desta t?cnica obtemos o diagrama de fases e seus pontos cr?&#305;ticos com respectivos expoentes cr?ticos v. O modelo apresenta quatro fases: ferromagn?tica, paramagn?tica e duas intermedi?rias. Nove pontos cr?&#305;ticos foram encontrados, sendo tr?s de classe de universalidade Ising, tr?s Potts de quatro estados, um Potts de oito estados e dois com classe de universalidade n?o correspondente a nenhum Potts com n?mero inteiro de estados

This bachelor’s thesis aims to show an extensive overview of all the parts that build up an electric load driven longboard and see if a load controlled longboard can be seen as a safe, comfortable and convenient alternative to the more common remote controlled longboard. The thesis will also answer how weight can be measured on a longboard in the most effective way, what the most comfortable riding technique is and what a good motor-battery configuration to be able to travel at 30 km/h and 10 km would be. The longboard measures the weight distribution with load cells located between the deck and the trucks. An Arduino translates the input from the load cells to a certain speed and then sends it to an ODrive which controls a BLDC motor that is powered by two LiPo batteries. The results show that a load controlled longboard can very well be seen as a good alternative if right riding technique is used. The best technique is when the longboard accelerates when the rider tilts and keeps a constant speed when the rider stands straight. The best way to measure the weight is to fasten the trucks with hinges which lets the load cells register weight without anything interfering. Not all tests could be done because of Covid-19 but a measured top speed of 15 km/h with a high gear ratio is a promising result for the future when more suitable gear ratios will be tested to try to reach the goal of 30 km/h. / Det här kandidatexamensarbetet strävar efter att visa en omfattande överblick på alla delar som bygger upp en elektrisk lastdriven longboard och se om en laststyrd longboard kan ses som ett säkert, komfortabelt och behändigt alternativ till den vanligare radiostyrda longboarden via handkontroll. Det här arbetet kommer också svara på hur vikt kan mätas på en longboard på ett så effektivt sätt som möjligt, vad som är den mest bekväma åkstilen och vad är en bra motor-batteri konfiguration för att kunna åka i 30 km/h och nå 10 km skulle vara. Longboarden mäter viktfördelningen med lastceller som är placerade mellan brädan och truckarna. En Arduino omvandlar indatan från lastcellerna till en specifik hastighet som den sedan skickar till en ODrive som kontrollerar en borstlös likströmsmotor som i sin tur är driven av två LiPo batterier. Resultaten visar att en laststyrd longboard kan mycket väl ses som ett bra alternativ om rätt åkstil används. Den bästa stilen är att longboarden accelererar när åkaren lutar sig och håller en konstant hastighet när åkaren står rakt. Det bästa sättet att mäta vikt är att montera truckarna på gångjärn som låter lastcellerna mäta vikt utan att något stör. Alla tester kunde inte utföras på grund av Covid-19 men en uppmätt topphastighet på 15 km/h med en hög utväxling är ett lovande resultat för framtiden när lämpligare utväxlingar kommer testas för att försöka nå målet på 30 km/h.

Esta pesquisa teve como objetivo desenvolver um anemômetro de fio quente para operar à corrente constante usando-se como elemento sensível, um termoresistor de platina, como braço da ponte de Wheatstone, para medir o fluxo de um fluido escoando em um tubo. Um protótipo do equipamento foi montado interligando as partes analógicas e digitais. Um circuito eletrônico microcontrolado foi construído para aquisição dinâmica de sinais, caracterizando a parte analógica. O sistema possui um condicionador analógico para o canal de entrada, possibilitando a leitura do sinal proveniente do transdutor anemométrico, controle de corrente do termoresistor de platina, controle da temperatura do elemento resistivo e ajuste de tensão para compatibilidade com a parte digital. A parte digital do sistema baseia-se no microcontrolador CY8C29466 com tecnologia PSoC - Programmable System on Chip da Cypress. Apresenta interface com o usuário através de teclado e mostrador de cristal liquido. A taxa de aquisição é de 10 amostras/s e o armazenamento dos dados é feito em memória EEPROM interna ao microcontrolador. Para a calibração do anemômetro de sinais foi adotado o procedimento de calibração dinâmica, tendo como referência um Becker graduado, uma balança de precisão de 0.1g e um cronômetro digital. Foi determinado o comportamento do condicionador através de ensaios dinâmicos, sendo apresentados gráficos de resultados de vazões em função dos valores de tensão provenientes da ponte de Wheatstone. Os dados resultantes de ensaios dinâmicos e simulações foram adquiridos por um osciloscópio digital, multímetro digital, software de simulação PROTEUS 7.1 e pelo sistema de aquisição desenvolvido. São mostrados gráficos comparativos dos sinais obtidos e simulados com ambos os equipamentos.

Arbetet är baserat på utveckling av mätinstrumentet Algometer som används för att mäta smärttrösklar hos individer. Mätinstrumentet är baserat på enkortsdatorn Raspberry Pi och en kraftgivare som mäter tillämpad tryck. Raspberry Pi hanterar algoritmer för återkoppling, mätresultatdokumentation samt användargränssnitt. Kraftgivarens konstruktion består av trådtöjningsgivare som är proportionell till den applicerade trycket. Arbetet framlägger konstruktion, rekommenderade kopplingar för att mäta storheter, samt en del av programmeringskoden för mätinstrument och användargränssnitt.