Two new types of laser doppler flowmeters prototypes validation

A fluxometria laser Doppler (LDF) é uma técnica para avaliação em tempo real do fluxo microcirculatório em tecidos biológicos. Esta técnica pode ser usada para monitorização não invasiva da microcirculação (por exemplo, avaliação da perfusão na pele), ou para monitorização da perfusão de forma invasiva (por exemplo, avaliação da perfusão no cérebro). Nesta tese, pretende-se acrescentar ao estado da arte da LDF, quando aplicada à monitorização não invasiva da perfusão na pele, a capacidade de discriminação em profundidade. Para isso, foi desenvolvido um protótipo de um fluxómetro laser Doppler com vários comprimentos de onda e diferentes separações entre as fibras emissora e receptora. Tendo em vista a monitorização de perfusão de cérebro de rato construiu-se um protótipo de um fluxómetro laser Doppler baseado na técnica self-mixing utilizando micro-fibras ópticas de forma invasiva. Para validar estes dois novos protótipos, fizeram-se simulações Monte Carlo do transporte de luz em tecidos. Realizaram-se simulações num fantoma (constituído por seis camadas de fluido a diferentes profundidades), e num modelo da pele para a validação do protótipo não invasivo. Os resultados demonstraram que o primeiro momento do especto de potência (M1), assim como, a profundidade atingida pelos fotões, aumentam com o incremento da distância entre as fibras emissora e receptora. Para além disso, os resultados evidenciaram que o acréscimo do comprimento de onda da luz laser traduz-se numa maior profundidade média amostrada. Medições realizadas com o protótipo não invasivo no fantoma e na pele foram comparados com os resultados das simulações. As simulações aproximam-se bastante dos resultados das medições Para a validação do protótipo invasivo, foram efectuadas simulações Monte Carlo num modelo de cérebro de rato. Foi demonstrado que a profundidade média medida com a sonda construída é de 0.15 mm

Medical Laser-Induced Thermotherapy - Models and Applications

Heat has long been utilised as a therapeutic tool in medicine. Laser-induced thermotherapy aims at achieving the local destruction of lesions, relying on the conversion of the light absorbed by the tissue into heat. In interstitial laser-induced thermotherapy, light is focused into thin optical fibres, which are placed deep into the tumour mass. The objective of this work was to increase the understanding of the physical and biological phenomena governing the response to laser-induced thermotherapy, with special reference to treatment of liver tumours and benign prostatic hyperplasia. Mathematical models were used to calculate the distribution of light absorption and the subsequent temperature distribution in laser-irradiated tissues. The models were used to investigate the influence on the temperature distribution of a number of different factors, such as the design of the laser probe, the number of fibres, the optical properties of the tissue, the duration of irradiation, blood perfusion and boundary conditions. New results concerning transurethral microwave thermotherapy were obtained by incorporating the distribution of absorbed microwaves into the model. Prototypes of new laser applicators for anatomically correct treatment of benign prostatic hyperplasia were developed and tested ex vivo. Experimental work on liver tumours pointed to the importance of eliminating the blood flow in the liver during treatment to reduce convective heat loss. In addition, it was shown that hepatic inflow occlusion during treatment increased the thermal sensitivity of tumour tissue. The dynamic influence of interstitial laser thermotherapy on liver perfusion was investigated using interstitial laser Doppler flowmetry. Vessel damage after the combined treatment of laser-induced heat treatment and photodynamic therapy was studied

Numerical Simulations

This book will interest researchers, scientists, engineers and graduate students in many disciplines, who make use of mathematical modeling and computer simulation. Although it represents only a small sample of the research activity on numerical simulations, the book will certainly serve as a valuable tool for researchers interested in getting involved in this multidisciplinary field. It will be useful to encourage further experimental and theoretical researches in the above mentioned areas of numerical simulation

Aeronautical engineering: A continuing bibliography with indexes (supplement 279)

This bibliography lists 759 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1992. Subject coverage includes: design, construction, and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Innovative contributions on calibration methodologies towards reliable microflow measurements

Flow measurement is critical in healthcare, chemistry and pharmaceutics, to mention a few. In fact, there are several applications in the microflow and nanoflow range, such as scaled-down process technology, drug development, and special health-care applications, as organ-on-a- chip technology. Nevertheless, the majority of the instruments used for the specified applica- tions are not sufficiently studied regarding their flow accuracy and traceability. Hence these fluid applications at the micro and nanoscale still lack well defined calibration methodologies for the devices working at the mentioned flow range with adequate uncertainty values. The work presented in this thesis focuses on the development and improvement of in- novative applications of calibration methodologies for microflow measuring instruments. The gravimetric method already implemented at IPQ from 120 L/h to 2000 mL/h was used and improved for low flow rates down to 10 L/h. Additionally, other 4 methods were developed to enable the calibration of micro/nano flows in a non-intrusive way. They are interferometry, pending drop, front track and comparison method (where a calibrated flow generator is used as the reference standard). The methodology that is best suited for each specific instrument and each measurement range, with the lowest uncertainty, was successfully identified along with the relevant influence factors in microflow measurements. A specific objective of this work was to increase the measuring range of IPQ-LVC down to 5 nL/min (0.3 L/h) with a 3% target uncertainty (k=2). This objective was possible to achieve and even surpass with the use of the interferometric method, where measurements were per- formed down to 1.6 nL/min (0.1 L/h) with 2 % uncertainty(k=2). This method was internally validated by comparison with the gravimetric method and is now in the process of external validation by EURAMET project 1508.A medição de caudal é extremamente importante em áreas como a saúde, a indústria química ou farmacêutica. Caudais à escala micro/nanométrica são já utilizados em várias aplicações, nomeadamente, processos tecnológicos de redução de escala, desenvolvimento de fármacos e especialmente em novas aplicações na área da saúde, tais como a tecnologia de órgãos-em- chip. Os sistemas de medição utilizados nas aplicações indicadas, por serem relativamente recentes, não estão ainda suficientemente estudados quanto a sua exatidão e rastreabilidade. É, assim, necessário desenvolver metodologias de calibração específicas para os referidos cau- dais com incertezas de medição adequadas. Este trabalho irá focar-se no desenvolvimento e melhoramento de metodologias de cali- bração de instrumentos utilizados na medição de micro/nanocaudal de fluidos. O método gra- vimétrico já implementado no IPQ numa gama de medição de 120 L/h a 2000 mL/h foi me- lhorado de forma se realizarem calibrações até 10 L/h. Foram ainda desenvolvidos 4 novos métodos, a interferometria, o método da gota pendente, o método do deslocamento de me- nisco e o método comparativo (onde um gerador de caudal é utilizado como referência). A metodologia que melhor se aplica a cada instrumento e a gama de medição, com a melhor incerteza foi identificada, assim como fatores de influência na medição de microcaudal. Um objetivo específico deste trabalho foi aumentar o intervalo de medição do IPQ-LVC para 5 nL/min (0.3 L/h) com uma incerteza de (k=2). Isso foi possível e até ultrapassável com a utilização do método interferométrico, em que as foram realizadas medições até 1.6 nL/min (0.1 L/h) com 2% de incerteza (k=2). Este método foi validado internamente por comparação com o método gravimétrico e está agora em processo de validação externa através do projeto EURAMET 1508

Mesurage en continu des flux polluants en MES et DCO en réseau d'assainissement

Les débitmètres sont des technologies connues et fortement répandues mais pas exemptes d erreurs, dont les causes peuvent être assez variées. Ces capteurs installés dans les systèmes d assainissement ne sont de plus pas rigoureusement étalonnables in situ. Une méthode de vérification in situ des débitmètres, utilisable pour des pseudos étalonnages, est présentée. En effet, l injection ponctuelle d un traceur dans un écoulement permet de calculer le débit et son incertitude d une manière indépendante des sondes en place. Cette méthodologie, en sept étapes, offre des résultats comparables à ceux fournis par des méthodes considérées comme des références (traçages aux sels et débitmètre électromagnétique). Des premiers essais en réseaux unitaires ont été réalisés pour la vérification de débitmètres (le long d un collecteur du Grand Lyon) et pour le calage de courbes de tarages (sur le Syndicat Intercommunal d Assainissement Grand Projet). Pour les mesures qualitatives des effluents, de nombreuses études antérieures ont montrées de bonnes corrélations entre les concentrations en polluants et les signaux fournis par des turbidimètres et des spectromètres UV/visible. Un pilote expérimental et des campagnes d échantillonnages sur des effluents prétraités de la station d épuration de Fontaines sur Saône ont été mis en place pour répondre aux objectifs suivants : i) concevoir et tester un site de mesure de nouvelle génération, ii) chercher des modèles de régressions entres différents capteurs (turbidimètres mono et bi-longueur(s) d onde(s), conductimètre, pHmètre, spectromètre UV/visible, capteurs à micro-ondes) et les concentrations en polluants pour les échantillons de temps sec, de temps de pluie et la totalité, iii) caractériser la performance de ces modèles et iv) tester la robustesse des méthodes proposées sous des conditions atypiques mais susceptibles d être rencontrées en réseau d assainissement. Les résultats confirment les bonnes corrélations entre certains paramètres (turbidité, conductivité et spectre UV/visible) et les concentrations en polluants. Aucun capteur n est le plus performant pour l ensemble des polluants. La majorité des capteurs délivrent des estimations comparables aux incertitudes près mais ces estimations sont peu voire pas redondantes aux analyses effectuées sur les échantillons. La conception du banc (et les variations des matrices des eaux usées) et/ou les conditions expérimentales lors des tests de robustesse sont peut être en cause.Flowmeters are well known technologies and highly prevalent but not free of errors, the causes can be quite varied. These sensors installed in sewer systems can t be in situ calibrate. A method of in situ verification of flow meters, used for pseudo-calibrations, is presented. Indeed, the injection of a tracer in a flow allows to calculate the flow and its uncertainty in a manner independent of probes in place. This methodology, in seven steps, provides results comparable to those provided by methods considered standards (tracer salts and electromagnetic flowmeter). The first applications in combined sewers were conducted for verification of flowmeters (along a main pipe of Greater Lyon) and for calibrations curves (the Syndicat Intercommunal Grand Sanitation Project). For qualitative measures of influents, many previous studies have shown good correlations between pollutant concentrations and the signals provided by turbidimeters and UV/visible spectrometers. A pilot and experimental samples taken during campaigns on the pretreated influent of the waste water treatment plant of Fontaines-sur-Saône, a bench was built to meet the following objectives: i) design and test a site measuring of a new generation, ii) seek regression models among different sensors (single and dual length(s)-wavelength(s) turbidimeters, conductivity meter, pH meter, UV/visible spectrometer, microwave sensors) and pollutant concentrations for samples of dry weather, wet weather and all, iii) characterize the performance of these models and iv) test the robustness of the proposed methods under atypical conditions but succeptibles to be encountered in sewers. The results confirm the good correlations between few parameters (turbidity, conductivity and UV/Vis fingerprint) and pollutant concentrations. No sensor is the most efficient for all pollutants. The majority of sensors deliver similar estimates to uncertainties but these estimates are little or no redundant with laboratory analysis. The design of the bench (and changes in wastewater matrices) and / or experimental conditions during the tests of robustness may be involved.VILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

The 1991 Marshall Space Flight Center research and technology

A compilation of 194 articles addressing research and technology activities at the Marshall Space Flight Center (MSFC) is given. Activities are divided into three major areas: advanced studies addressing transportation systems, space systems, and space science activities conducted primarily in the Program Development Directorate; research tasks carried out in the Space Science Laboratory; and technology programs hosted by a wide array of organizations at the Center. The theme for this year's report is 'Building for the Future'

JSC research and technology

The primary roles and missions of JSC incorporate all aspects of human presence in space. Therefore, the Center is involved in the development of technology that will allow humans to stay longer in Earth orbit, allow safe flight in space, and provide capabilities to explore the Moon and Mars. The Center's technology emphasis areas include human spacecraft development, human support systems and infrastructure, and human spacecraft operations. Safety and reliability are critical requirements for the technologies that JSC pursues for long-duration use in space. One of the objectives of technology development at the Center is to give employees the opportunity to enhance their technological expertise and project management skills by defining, designing, and developing projects that are vital to the Center's strategy for the future. This report is intended to communicate within and outside the Agency our research and technology (R&T) accomplishments, as well as inform Headquarters program managers and their constituents of the significant accomplishments that have promise for future Agency programs. While not inclusive of all R&T efforts, the report presents a comprehensive summary of JSC projects in which substantial progress was made in the 1992 fiscal year. At the beginning of each project description, names of the Principal Investigator (PI) and the Technical Monitor (TM) are given, followed by their JSC mail codes or their company or university affiliations. The funding sources and technology focal points are identified in the index

Aeronautical engineering: A continuing bibliography with indexes (supplement 231)

This bibliography lists 469 reports, articles, and other documents introduced into the NASA scientific and technical information system in September, 1988