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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Dual modality tomography for the monitoring of constituent volumes in multi-component flows

Daniels, A. R. January 1996 (has links)
This thesis describes an investigation into the use of dual modality tomography to monitor multi-component flows. The concept of combining two modalities for this purpose evolved from a desire by the Water Research Council to determine volume flow rates of the major components of sewage. No single sensing method is capable of detecting all suspended solids in sewage flows therefore a decision was taken to combine the technologies of electrical resistance and optical tomography to produce a single measurement system. Sensors for both were positioned around the periphery of a static, circular phantom to allow comparisons between dual and single modalities. Modelling was carried out to determine the behaviour of the electrical impedance and optical tomography technologies in a three dimensional situation, where a variety of flow components exist. This provided a greater understanding of the problems involved in combining these technologies and an appreciation of the potential benefits. The remainder of the work can be divided into three areas. Firstly, hardware was constructed to make voltage measurements for both modalities. Secondly, software was written to perform data acquisition, data manipulation and image reconstruction using a simple back projection algorithm developed for this purpose. Finally, an integration of the individual hardware and software components was performed to produce a dual modality system on which tests were carried out to determine the resulting benefits over single modality alternatives.
22

Avaliação do processo de desenvolvimento de desmineralização em esmalte dental humano utilizando a técnica de tomografia por coerencia óptica / Human dental enamel demineralization process assessment using the optical coherence tomography technique

CARA, ANA C.B. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:34:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:10Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:10/03123-8
23

Avaliação do processo de desenvolvimento de desmineralização em esmalte dental humano utilizando a técnica de tomografia por coerencia óptica / Human dental enamel demineralization process assessment using the optical coherence tomography technique

CARA, ANA C.B. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:34:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:10Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A detecção de lesões cariosas nos estágios iniciais possibilita a escolha de tratamentos baseados na preservação da estrutura dental. Dessa forma, a utilização de exames capazes de diagnosticar precocemente essas lesões, como a Tomografia por Coerência Óptica (OCT Optical Coherence Tomography) é adequada. Assim, o objetivo do trabalho foi avaliar a capacidade da OCT em quantificar os estágios de desmineralização do esmalte durante o desenvolvimento de lesões simuladas de cárie, tendo como padrão de referência o teste de microdureza seccional. Foram utilizados 53 dentes terceiros molares hígidos, os quais tiveram as coroas seccionadas para obtenção de 210 amostras. Para avaliar as possíveis alterações sofridas por cada amostra, essas foram examinadas através da técnica de OCT no início do experimento e novamente examinadas após o término do período de ciclagem estabelecido para cada grupo, utilizando os coeficientes de atenuação óptica total e o cálculo de área em gráficos de intensidade de sinal de OCT, como parâmetros de análise. Posteriormente, as amostras foram submetidas a testes de microdureza seccional. A diferença entre os coeficientes de atenuação óptica obtidos antes e depois da ciclagem de pH apresentou elevado grau de correlação com os resultados de microdureza seccional. Por meio da análise das áreas provenientes de gráficos de intensidade de sinal de OCT e microdureza Knoop, ambos em função da profundidade, foi observada relação de linearidade entre os resultados e elevada correlação entre as técnicas avaliadas (ρ = 0,99). De acordo com os resultados, a técnica de OCT foi capaz de detectar diferentes graus de desmineralização do esmalte dental humano em lesões simuladas de cárie. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:10/03123-8
24

Diffuse Optical Tomographic Reconstruction In Low-Scattering Media : Development Of Inversion Algorithms Based On Monte-Carlo Simulation

Phaneendra Kumar, Y 01 1900 (has links) (PDF)
No description available.
25

The characterization of retinal nerve fiber layer thickness in normal,high-tension and normal-tension glaucoma using optical coherencetomography

Mok, Kwok-hei., 莫國熙. January 2005 (has links)
published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy
26

Development of diffuse optical tomography for imaging the brain /

Cheng, Xuefeng. January 2000 (has links)
Thesis (Ph.D.)--Tufts University, 2000. / Adviser: David A. Boas. Submitted to the Dept. of Electrical Engineering and Computer Science. Includes bibliographical references (leaves 139-147). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
27

Anatomical optical coherence tomography in the human upper airway /

Armstrong, Julian. January 2006 (has links)
Thesis (Ph.D.)--University of Western Australia, 2007.
28

Digital holographic microscopy a thesis /

Cheng, Yujuan. January 1900 (has links)
Thesis (Ph. D.)--Northeastern University, 2008. / Title from title page (viewed May 26, 2009). Graduate School of Engineering, Dept. of Electrical and Computer Engineering. Includes bibliographical references (p. 142-155).
29

Measuring the classical and quantum states and ultrafast correlations of optical fields /

McAlister, Daniel Frank, January 1999 (has links)
Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 197-201). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9948024.
30

Design of a transillumination optical tomography system to image tissue-engineered blood vessels /

Gladish, Jimmy January 2004 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 100-104). Also available on the Internet.

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