To help address the growing need for more and better sensors, an attempt was made to produce an in-situ mass and spectroscopic analysis of liquid and solid samples, to characterize samples and sensors. Spectroscopic analysis consisted of Raman and FTIR where mass measurements were carried out. The sample or sensor’s holder would allow for spectroscopic analysis as well as expose the sample to high temperatures and various chemicals. While Raman and FTIR were successful in producing reliable and consistent data, the constructed watt balance was not. This failure was a result of eliminate vibrational noise.

No description available.

A comparative study of three six-axis force sensors selected after an extensive literature survey is presented. A sensor to measure ground contact force at each foot of a walking machine is recommended. Principles of force sensing are reviewed and characteristics of sensing elements are discussed. Results of simulation of three six-axis force sensors are presented as behavior curves, sensitivity plots and compliance matrices. These simulations use finite element techniques. Condition numbers of compliance matrices are presented as a measure of overall sensor performance. Estimates of manufacturing costs are included as a final selection criterion. / Graduation date: 1994

This paper deals with the design of multi-axis force (also known as force/torque) sensors, as considered within the framework of optimal design theory. The principal goal of this paper is to identify a mathematical objective function, whose minimization corresponds to the optimization of sensor accuracy. The methodology employed is derived from linear algebra and analysis of numerical stability. The problem of optimizing the number of basic transducers employed in a multi-component sensor is also addressed. Finally, applications of the proposed method to the design of a simple sensor as well as to the optimization of a novel, 6-axis miniaturized sensor are discussed.

This thesis examines a complete design framework for a real-time, autonomous system with specialized VLSI hardware for computing 3-D camera motion. In the proposed architecture, the first step is to determine point correspondences between two images. Two processors, a CCD array edge detector and a mixed analog/digital binary block correlator, are proposed for this task. The report is divided into three parts. Part I covers the algorithmic analysis; part II describes the design and test of a 32$\time $32 CCD edge detector fabricated through MOSIS; and part III compares the design of the mixed analog/digital correlator to a fully digital implementation.

Transition edge sensors are the detectors of choice for a wide range of applications; from dark matter search, neutrino search, to cosmic radiation detection from near infrared to millimeter wavelengths. We are developing transition edge sensors using superconducting iridium thin films and we are proposing their use for future dark matter and neutrino search experiments. Our Ir films are deposited using an radio frequency (RF) magnetron sputtering and photolithographic techniques and measured using an adiabatic refrigerator capable of reaching temperatures of a few tens of mK. This thesis presents a detailed description of superconducting iridium thin films from the fabrication process to the characterization of the film properties at room temperature and low temperature. Alternative options for the bias circuit used to read out the TES signals will be discussed, we are proposing the use of RLC resonant circuits and transformers instead of SQUIDS.

Thesis (M.Sc.)(Microbiology)--University of Pretoria, 2006. / Includes summary. Includes bibliography. Available on the Internet via the World Wide Web.

No description available.

This PhD thesis introduces basic concepts of smart chemical sensors design, which are afterwards applied to a particular application: the analysis of natural gas. The thesis addresses thus two sets of objective, a first set of objectives related to the conceptual design of a smart chemical sensor using smart sensor standards: - The design of an optimal smart chemical sensor architecture - The novel combination in a working prototype of the highly complementary smart sensor standards IEEE-1451 and BS-7986 A second set of objectives is directly related to the selected application. Natural gas quality control. Natural gas is an energy source of major importance in the world energy supply, its quality control is increasingly important due to its origin-dependent properties and the progressive liberalization of the energy market. The objectives related to this application are: - To solve the natural gas quality analysis problem by using a lower cost approach taking advantage of MEMS technology, smart sensor features, and embedded intelligent signal processing. - To select suitable sensing technologies and associated signal processing. An overall goal addressed by the PhD Thesis is in the end the reporting of a working smart sensor prototype implementing all the smart sensor features, MEMS based natural gas analysis and advanced signal processing as a demonstration of a novel low-cost and high speed natural gas analyzer. The thesis covers this research along 7 chapters, introducing the concepts and application in chapters 1 and 2, the objectives in chapter 3, the simulation of a proposed MEMS sensor approach in chapter 4, the description of the advanced signal processing approach adopted in chapter 5, the description of the electronics and engineering of the smart natural gas analyzer prototype in chapter 6, and finally the conclusions of the work in chapter 7. / La tesis introduce conceptos básicos sobre el diseño de sensores químicos inteligentes, en particular presenta los estándares propuestos IEEE-1451 y BS-7986, y elabora una propuesta para el diseño óptimo de dichos sensores químicos inteligentes. Se implementa la propuesta de diseño para una aplicación concreta, el análisis de gas natural. Además de la aplicación de los conceptos sobre sensores químicos inteligentes se pretende además diseñar un analizador compacto, rápido y de bajo coste, para ello se estudia el uso de un microsensor termoeéctrico como sensor principal del analizador. Una vez probada su viabilidad se implementan ambos conceptos (sensores inteligentes y microsensor termoeléctrico) en un prototipo funcional validado en laboratorio. Como resultado se obtiene una propuesta para el diseño de sensores químicos inteligentes basada en estándares, y por otro lado se presenta un nuevo analizador de gas natural, más rápido y compacto que los existentes. Los resultados obtenidos originan diversas publicaciones en revistas así como dos patentes de método y sistema.

Actualment, és necessari disposar d'informació útil i en temps real per al desenvolupament sostenible en diversos camps. La monitorització és una eina eficaç per a la caracterització de processos industrials i mediambientals, i comprèn un conjunt de tasques aplicades amb la finalitat d'obtenir informació qualitativa i quantitativa de paràmetres indicadors d'un procés. Les tendències actuals en la monitorització són utilitzar tècniques analítiques i/o sistemes de transducció que subministrin informació ràpida, fiable i representativa sobre l'estat real del procés. Per això, cal apropar la instrumentació al procés i minimitzar la intervenció humana. Així doncs, els dispositius de mesura utilitzats han d'oferir selectivitat suficient, sensibilitat adequada, temps de resposta ràpid i llargs períodes operatius sense supervisió.El disseny d'analitzadors de procés basats en metodologies de flux continu i sensors electroquímics (potenciomètrics) com a detectors permetrien resoldre molts dels problemes existents derivats del mesurament directe en un procés complex i subministrarien informació de tipus químic en temps real. Aquests equips conjugarien les avantatges derivades de la integració del procediment analític que aporten els sensors químics potenciomètrics amb la simplificació en termes d'automatització, pretractament de mostra i funcionament autònom que aporten les metodologies de flux continu.La tesi presentada s'emmarca dintre de diferents projectes de desenvolupament i transferència tecnològica i estableix les bases d'aplicabilitat dels sensors químics potenciomètrics en termes de fiabilitat de la informació obtinguda i robustesa en llargs períodes de monitorització.Els resultats presentats han permès la monitorització d'un procés industrial de preparació d'isocianurat sòdic desenvolupant un sistema en flux que incorpora un ESI (elèctrode selectiu d'ions) de membrana amb portador mòbil carregat selectiu a monohidrogenisocianurat. D'altra banda, s'ha desenvolupat un analitzador automàtic de nitrat basat en la tècnica d'anàlisi per injecció en flux continu (FIA) i un dispositiu sensor selectiu a ió nitrat per a la determinació d'aquest paràmetre en l'etapa de nitrificació d'una planta pilot de tractament d'aigües residuals industrials. Per al mateix procés, s'ha desenvolupat un analitzador per a la monitorització de nitrit basat en una detecció colorimètrica de la reacció de Griess-Ilosvay. L'automatització del procediment s'ha dut a terme amb la tècnica FIA i integra una etapa de difusió gasosa per eliminar els problemes derivats de la mesura colorimètrica directa. Finalment, s'ha desenvolupat un sistema semiautomàtic d'anàlisi de fangs residuals per a la determinació indirecta de sulfur d'hidrogen. Aquest sistema integra una cel·la de pervaporació com a sistema d'extracció d'analits volàtils. Desprès de l'etapa de pervaporació, la determinació de l'ió sulfur es duu a terme de forma contínua mitjançant un elèctrode selectiu d'ions. / Nowadays, it is necessary to have useful information at real time for a sustainable development in different areas. Monitoring is a powerful tool for the industrial and environmental processes characterization and includes a set of tasks focused on the obtaining of qualitative and quantitative information of key process parameters. Monitoring approaches tend to use analytical techniques and/or transduction systems to afford feasible and real-time information about the process status. Therefore, it is necessary to situate the analysers in process stream and to minimize human intervention. Consequently, these devices have to provide enough selectivity, suitable sensitivity, short response time and to operate reliably over long periods of time without supervision.The process analysers based on flow continuous techniques and electrochemical sensors (potentiometric transduction) as detectors avoid most of the existing problems due to the direct measurements in complex processes and the obtaining of chemical information at real time. This instrumentation combines the advantage of the analytical procedure integration provided by chemical sensors and the simplicity in terms of automation, sample pre-treatment and unattended operation offered by continuous flow methodologies. The thesis presented is enclosed in different development and technological transfer projects and it establishes the applicability of potentiometric chemical sensors in terms of information reliability and robustness in long monitoring time.The results presented have allowed the monitoring of isocyanurate sodium manufacturing process by developing a flow continuous method which integrates an ISE (ion selective electrode) based on ion-exchanged carrier selective to monohidrogenisocyanurate. On the other hand, it has been developed an automatic analyser based on the flow injection analysis technique (FIA) and a chemical sensor selective to nitrate for the determination of this parameter in a nitrification stage from a pilot Waste Water Treatment Plant. For the same process, an automatic analyser for the nitrite monitoring based on the Griess-Ilosvay colorimetric reaction has been set up. The automation of the procedure has been carried out by FIA and it integrates a gas diffusion step to eliminate the problems due to the direct colorimetric method. Finally, it has been developed a semiautomatic analysis system for the indirect determination of hydrogen sulphide in sludge. This system integrates a pervaporation module to remove volatile analytes. After pervaporation, the detection of sulfide ion has been carried out continuously by means of an ion selective electrode.