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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.
61

Nano Thermal and Contact Potential Analysis with Heated Probe Tips

Remmert, Jessica Lynn 09 April 2007 (has links)
This work describes two closed-loop atomic force microscopy methods that utilize the heated silicon probe to interrogate surfaces. The first method identifies the softening temperatures of a selected polymer and organic substrate as a function of contact force and surface hardness. Motivation partly stems from nanosampling, which requires knowledge of phase-specific transitions to identify and extract mass from multicomponent systems for chemical analysis. In the second method, the cantilever is implemented as a Kelvin probe to study the effect of temperature on the measured contact potential. The objective is to ascertain whether the probe functions as a capable electrode for scanning Kelvin probe microscopy (SKPM) applications. This was achieved by performing heated force-distance experiments on a biased gold film with the tip operating at various potentials. Both experiments examine the interaction between the tip and substrate and analyze sample effects both induced and sensed by the cantilever.
62

Modeling time-resolved interaction force mode AFM imaging

Oral, Hasan Giray 06 April 2012 (has links)
Intermittent contact mode atomic force microscopy has been widely employed for simultaneous topography imaging and material characterization. The work in the literature includes both qualitative and quantitative methods. Regular AFM cantilevers are generally used in these methods, yet these cantilevers come with certain limitations. These limitations result from the very nature of cantilever probes. They are passive force sensors with insufficient damping. This prevents having active and complete control on tip-sample forces, causing sample damage and inaccurate topography measurement. Ideally, an AFM probe should offer high bandwidth to resolve interaction forces, active control capability for small interaction force and stable operation, and sufficient damping to avoid transient ringing which causes undesired forces on the sample. Force sensing integrated readout and active tip (FIRAT) probe offers these properties. A special imaging mode, time-resolved interaction force (TRIF) mode imaging can be performed using FIRAT probe for simultaneous topography and material property imaging. The accuracy of topography measurement of samples with variations in elastic and adhesive properties is investigated via numerical simulations and experiments. Results indicate that employing FIRAT probe's active tip control (ATC) capability during TRIF mode imaging provides significant level of control over the tip-sample forces. This improves the accuracy of topography measurement during simultaneous material property imaging, compared to conventional methods. Moreover, Active tip control (ATC) preserves constant contact time during force control for stable contact while preventing loss of material property information such as elasticity and adhesive forces.
63

Limitations à l'usage des sondes électrostatiques dans un plasma gazeux à haute pression : diagnostic et effets des métastables aux basses températures de plasma /

Fortin, Marc. January 1978 (has links)
Thèse (D.Sc.)--Université du Québec à Chicoutimi, 1978. / Document électronique également accessible en format PDF. CaQCU
64

Using membrane interface probe (MIP) to characterize chlorinated volatile organic compounds in glacial sediments

Washo, Dawn Llewellyn. January 2009 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Department of Geological Sciences, 2009. / Includes bibliographical references.
65

Sistema automático para caracterização de sensores a fibra óptica para alta tensão / Characterization system for fiber optics based sensors for high-voltage

Spengler, Anderson Wedderhoff, 1986- 16 August 2018 (has links)
Orientador: Elnatan Chagas Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-16T09:48:26Z (GMT). No. of bitstreams: 1 Spengler_AndersonWedderhoff_M.pdf: 5622371 bytes, checksum: dd49f965749d4c55fa19542a3a801d9c (MD5) Previous issue date: 2010 / Resumo: Esta dissertação aborda o projeto de um sistema de caracterização de sensores baseados em fibras ópticas para alta-tensão. O sistema é formado por dois módulos principais, um relacionado com a câmara térmica e outro relativo à alta-tensão. O desenvolvimento do sistema deve-se basicamente às necessidades de personalização e precisão para a caracterização dos sensores e outras aplicações. A câmara climática tem seu projeto eletrônico e mecânico descritos, com ênfase na utilização de módulos termoelétricos, nos controladores proporcional-integral-derivativos utilizados e os parâmetros de sintonia encontrados. Foi feito o estudo da configuração que utiliza dois módulos termoelétricos em série, apontando as vantagens e desvantagens desta configuração. A faixa de temperatura para a câmara obtida é de 0 ºC até 70 ºC, com erro ±0,1 ºC semelhantes às câmaras climáticas comerciais. Há a proposta de um circuito gerador e analisador de ondas arbitrárias de alta-tensão, e ensaios com um sistema semelhante ao proposto para tensões de até 15 kV, para validação do método de eliminação de harmônicas proposto nesta dissertação, obtendo resultados de THD da ordem de 0,04%, valor este limitado pela definição do analisador de sinais / Abstract: This work discusses the project of a characterization system fiber optics based sensors for high-voltage. The system consists of two main modules, one related to the thermal chamber and another on high-voltage part. The system development was mainly due to the needs of customization and precision for the characterization of sensors and other applications. The thermal chamber has its electronic and mechanical design described, with emphasis on the use of thermoelectric modules, the proportional-integral-derivative controllers and their tuning parameters. A study was conducted on the configuration that uses two thermoelectric modules in series, showing the advantages and disadvantages of this configuration. The obtained temperature range for the chamber was 0°C to 70 °C with ± 0.1 °C error, similar to the commercial chambers. There is a proposal for a circuit for arbitrary high voltage wave generator and analyzer, and tests with one system similar to that proposed for voltages up to 15kV, to validate a harmonics eliminator method, obtaining results of THD about 0.04% which is limited by the definition of signal analyzer / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica
66

Contribuição ao estudo de um medidor não-invasivo da espessura da camada de agua em um escoamento anular oleo-agua / Contribution to the study of a non-invasive probe for measuring the water thickness in a core-annular flow

Galdiano, Eder dos Santos 15 August 2018 (has links)
Orientadores: Leonardo Goldstein Junior, Emerson dos Reis / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-15T08:49:00Z (GMT). No. of bitstreams: 1 Galdiano_EderdosSantos_M.pdf: 3731509 bytes, checksum: 5415460955079bfdf8773ebcc4ee6500 (MD5) Previous issue date: 2010 / Resumo: Esse trabalho é uma contribuição ao estudo de uma sonda não-intrusiva para medição da espessura da camada anular de escoamentos bifásicos óleo-água - core-flow. É discutida a construção do sensor capacitivo da sonda. Dela são avaliados o desempenho estático, numa bancada construída para este fim, e o dinâmico na presença de escoamento numa bancada existente no Laboratório de Petróleo (LabPetro). Através dos testes estáticos, foram obtidas informações sobre a resposta da sonda: formato da curva de resposta, sensibilidade, faixa de medição, e estudou-se o efeito da condutividade da água. Os dados experimentais foram comparados com resultados de simulação numérica obtidos por outro autor. Nos testes dinâmicos, foi utilizada uma técnica de medição da espessura da camada de água através de imagens de filmagens registradas do escoamento, sendo que estes dados foram comparados com os obtidos com a sonda capacitiva, assim permitindo a avaliação do seu desempenho no escoamento. Os resultados demonstram potencial do sistema proposto, mas também apontam para a necessidade de novos estudos e aperfeiçoamentos / Abstract: This work is a contribution to the study of a non-intrusive probe for measurement of the thickness of the water layer of a core-annular flow. A capacitive probe was built and its static performance was evaluated from tests executed in a specially designed bench-scale apparatus. In addition, evaluation of the dynamic performance was made possible from fluid-flow tests in a multiphase flow loop. From the static tests information was obtained about the probe output: shape of the produced response, sensitivity, range and the water electrical conductivity effect. The experimental data were compared with results of a numerical simulation available from a different author. In the dynamic tests the measurement technique used to obtain the thickness of the annular water layer consisted of a sequence of photographic images from a fast camera. The results were compared with those from the capacitive probe, allowing the evaluation of its performance in the presence of fluid flow. The results demonstrate the potential of the considered system, but they also point out to the necessity of new studies and development / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica
67

O desenvolvimento da poética eletroacústica na trilha sonora de filmes de ficção científica norte-americanos / The development of electroacoustic\'s poetic on north-american science fiction movies\' soundtracks

Juliano de Oliveira 08 October 2012 (has links)
Nesta dissertação, buscou-se realizar um estudo histórico e analítico acerca do desenvolvimento da poética e dos processos da música eletroacústica na trilha sonora - principalmente na trilha musical - do cinema de ficção científica norte-americano. A música eletroacústica, a começar por suas primeiras manifestações através dos instrumentos eletrônicos e de técnicas de manipulação de tape magnético, esteve associada, desde o início do cinema sonoro, à ficção científica e ao terror. Na década de 1950, com o início da era de exploração espacial no cinema norte-americano, os sons eletrônicos se associaram ao universo alienígena e às narrativas de futuro. Nos anos seguintes, os gestos e funções indiciais desses primeiros instrumentos foram adaptados aos sintetizadores e às novas gerações de dispositivos eletrônicos. Assim, lentamente se consolidou uma tradição que relacionaria, durante os anos subsequentes, a música eletroacústica às narrativas de suspense, terror e ficção científica. Para entender como se deu a utilização de sons eletrônicos no cinema de ficção científica ao longo do século XX, partimos da exposição de alguns pressupostos metodológicos de análise audiovisual e de música eletroacústica. Estes, por sua vez, serviram como norteadores para as análises realizadas no final da dissertação. Posteriormente, seguimos por dois caminhos: um, cujo objetivo é descrever o desenvolvimento dos processos formadores da poética da música eletroacústica e seu uso no cinema; e outro, onde tentamos delinear o desenvolvimento da trilha sonora de filmes de ficção científica que se apropriaram de elementos advindos da música eletroacústica. No último capítulo, realizamos a análise de quatro filmes de diferentes períodos. Cada filme selecionado pode ser considerado representativo no uso de processos e técnicas da música eletroacústica de sua época; são eles: O planeta proibido (1956), THX 1138 (1971), Tron: uma odisseia eletrônica (1982) e A última profecia (2002). / The electroacoustic music, starting with its first manifestations such as electronic instruments and magnetic tape manipulation techniques, have been associated, since the beginning of movies with sound, to science fiction and horror. In the 50\'s, with the beginning of an era of space exploration in north-american motion pictures, the electroacoustic sounds were definitely associated with the alien\'s universe and futuristic narratives. In the following years, the gestures and functions of those first instruments were adapted to the synthesizers and to the new electronic device generation. Thus, it slowly consolidated a tradition that would relate the electroacoustic music to suspense, horror and science fiction narratives for the subsequent years. In order to understand how the use of electronic sounds in science fiction movie pictures happened during the twentieth century, we will start with the exposure of some methodological assumptions of audio-visual and electroacoustic music analysis. These will, on the other hand, work as guides for the final analysis in the end of this dissertation. Afterwords, we followed through two paths: one of them aimed to describe the developmental processes of electroacoustic music\'s poetic since its origin and its use in the cinema; and for the other path we tried to outline the soundtrack\'s development of science fiction motion pictures that made use of elements coming from electroacoustic music. Each selected movie may be considered representative of its own time in this use of electroacoustic music\'s processes; which are: Forbidden Planet (1956), THX 1138 (1971), Tron (1982) and The Mothman Prophecies (2002).
68

Ion Scattering in a Self-Consistent Cylindrical Plasma Sheath

Figueroa, Shana Suzanne 10 May 2006 (has links)
The Turning Point Method (TPM) for the evaluation of ion scattering in a sheath of a biased probe immersed in an unmagnetized plasma is reviewed. The TPM implemented originally in a computer program for spherical probes is expanded to include cylindrical probes as well as the evaluation of the turning angle of the charged particle (repelled or attracted) around the probe. TPM results have the potential to provide a standard against which to compare more complicated current collection simulations. TPM results are validated by comparing with Laframboise's earlier work for current collection in the Orbital Motion Limited regime. Calculations of the turning angle of a charged particle with specific energy and angular momentum revealed that higher plasma shielding limits the range of impact parameters that experience significant scattering, and that attracted particles entering tangent to the sheath experience increased scattering. The TPM results also show that there are significant changes in orbital trajectories between different space charges within the Orbital Motion Limited limit.
69

Process development and reliability study for 01005 components in a lead-free assembly environment

Bhalerao, Vikram. January 2008 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008. / Includes bibliographical references.
70

Probe Modules for Wafer-Level Testing of Gigascale Chips with Electrical and Optical I/O Interconnects

Thacker, Hiren Dilipkumar 10 July 2006 (has links)
The use of optical input/output (I/O) interconnects, in addition to electrical I/Os, is a promising approach for achieving high-bandwidth, chip-to-board communications required for future high-performance gigascale chip-based systems. While numerous efforts are underway to investigate the integration of optoelectronics and silicon microelectronics, virtually no work has been reported relating to testing of such chips. The objective of this research is to explore methods that enable wafer-level testing of gigascale chips having electrical and optical I/O interconnects. A major challenge in achieving this is to develop probe modules which would allow high-precision, temporary interconnection of a multitude of electrical and optical I/Os, in a chip-size area, to automated test equipment. A probe module would need to do this in a rapid, step-and-repeat manner across all the chips on the wafer. In this work, two candidate probe modules were devised, batch-fabricated on Si using microfabrication techniques, and successfully demonstrated. The first probe module consists of compliant electrical probes (10^3 probes/cm^2) fabricated alongside grating-in-waveguide optical probes. The second module consists of micro-opto-electro-mechanical-systems (MOEMS)-based microsocket probes (10^4 probes/cm^2) to interface a chip with polymer pillar-based electrical and optical I/Os. High-density through-wafer interconnects are an essential attribute in both probe substrates for transferring electrical and optical signals to the substrate back-side. Fabrication and characterization of metal-clad, metal-filled, and polymer-filled through-wafer interconnects as well as process integration with probe substrate fabrication are described and numerous possible redistribution schemes are explicated. Chips with optical and electrical I/Os are an emerging technology, and one that test engineers are likely to encounter in the near future. The contributions of this thesis are to help understand and address the issues relating to joint electrical and optical testing during manufacturing.

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