Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-06Bitstream added on 2014-06-13T20:18:25Z : No. of bitstreams: 1 freitasjr_jl_me_guara.pdf: 1619418 bytes, checksum: c9f600bef1bd4a38f5a6b1437fb62dd6 (MD5) / Universidade Estadual Paulista (UNESP) / Sistemas micro-eletromecânicos (MEMS) é uma tecnologia revolucionária que envolve a miniaturização de componentes e estruturas para a transdução, atuação e controle de sinais, através de interfaces eletrônicas, afetando a forma que pessoas e máquinas interagem com o mundo físico. Este avanço tecnológico é conseqüência da integração de áreas multidisciplinares, que possibilitou o desenvolvimento de componentes de pequenas dimensões, de baixo consumo e operando em diferentes ambientes. O objetivo deste trabalho foi estudar a aplicabilidade de sensores de aceleração tipo capacitivo que utilizam desta tecnologia, visando desenvolver um sistema para monitoramento de sinais de vibração em máquinas rotativas, levando em consideração o custo, a portabilidade e a capacidade de monitoramento de sinais na faixa entre zero e 5kHz. Os resultados foram satisfatórios, alcançando os objetivos propostos. / Micro-electromechanical Systems (MEMS) is a revolutionary technology involving miniaturization of components and structures to transduction, performance and control of signals, through electronic interface, affecting the form that people and machines interact with the physical world. This technologic progress is consequence of the integration of several areas, which made possible the development of devices with small dimensions, requiring low power and able to operate in several environments. The objective of this work was to study the applicability of the capacitive sensor based in this technology, seeking to develop a monitor system for vibration in rotative machines, taking into account the cost, the portability and the capacity of work with frequency between zero and 5kHz. The results were satisfactory, reaching the proposed objectives.

Orientador: Mauro Hugo Mathias / Banca: Sandro Aparecido Baldacim / Banca: João Zangrandi Filho / Resumo: Sistemas micro-eletromecânicos (MEMS) é uma tecnologia revolucionária que envolve a miniaturização de componentes e estruturas para a transdução, atuação e controle de sinais, através de interfaces eletrônicas, afetando a forma que pessoas e máquinas interagem com o mundo físico. Este avanço tecnológico é conseqüência da integração de áreas multidisciplinares, que possibilitou o desenvolvimento de componentes de pequenas dimensões, de baixo consumo e operando em diferentes ambientes. O objetivo deste trabalho foi estudar a aplicabilidade de sensores de aceleração tipo capacitivo que utilizam desta tecnologia, visando desenvolver um sistema para monitoramento de sinais de vibração em máquinas rotativas, levando em consideração o custo, a portabilidade e a capacidade de monitoramento de sinais na faixa entre zero e 5kHz. Os resultados foram satisfatórios, alcançando os objetivos propostos. / Abstract: Micro-electromechanical Systems (MEMS) is a revolutionary technology involving miniaturization of components and structures to transduction, performance and control of signals, through electronic interface, affecting the form that people and machines interact with the physical world. This technologic progress is consequence of the integration of several areas, which made possible the development of devices with small dimensions, requiring low power and able to operate in several environments. The objective of this work was to study the applicability of the capacitive sensor based in this technology, seeking to develop a monitor system for vibration in rotative machines, taking into account the cost, the portability and the capacity of work with frequency between zero and 5kHz. The results were satisfactory, reaching the proposed objectives. / Mestre

In this project, fabrication and characterization of nano/microfluidic channels on borosilicate glass substrate were carried out using a Photo/Ultraviolet (UV) lithography method, which has applications in single-cell analysis. In our single-cell analysis glass system, the bacterial cells will be made to sit in the micrometer channels and also the sub-micron size channels around 300 nm is aspired so it helps in passing the fluid to the outlet hole while holding the cells back. This system will help in the microscopic analysis of the bacterial cell growth over generations. A multi-layer mask approach is used to pattern the etch masks on a glass for the consecutive Isotropic wet etching of the glass substrate. Isotropic wet etching is utilized to transfer the patterned structures from a metal mask to the glass and also to under etch the differently sized spacing pitches (area separating nano/microfluidic channels in our design) to obtain sub-micron channel dimensions. Many test structures were designed on the photomask to optimize during the fabrication process with combinations of differently sized channels with differently sized spacing pitches ranging from 300 nm to 300 µm dimensions. In order to obtain this sub-micron sized channels on glass using a UV lithography technique is a challenging task, so the initial aim was to use the designed spacing pitches present between the channels as a platform to isotopically etch and create an under etched space width size in sub-micrometer. But we were able to obtain channel structure in sub-micron scale directly by optimizing multiple steps of the fabrication process. Characterization of the nano/microfluidic channels was done with the help of Optical microscopy and Dektak profilometer to measure the width, depth and uniformity of the structures during the optimization of the lithography process and scanning electron microscope (SEM) images were taken to analyze the channel dimensions and to get images of the fabricated channels.

American football is one of the most popular sports in the United States. However, in comparison to other mainstream sports such as soccer and rugby, there is limited literature using scientific principles and theory to examine the most appropriate ways to monitor the sport. This serves as a barrier to American football practitioners in their development and implementation of evidence-based sport preparation programs. Therefore, the primary aim of this line of research (i.e., dissertation) is to illustrate the efficacy of commonly used athlete monitoring tools within the sport of American collegiate football, while proposing a systematic framework to guide the development of an athlete monitoring program. This aim was achieved through a series of studies with the following objectives: 1) to quantify the physical demands of American collegiate football practice by creating physiological movement profiles through the use of integrated microtechnology metrics and heart rate indices, 2) to determine the positional differences in the physical practice demands of American collegiate football athletes, 3) to examine which integrated microtechnology metrics might be used to most efficiently monitor the training load of American collegiate football athletes, 4) to demonstrate the suitability of using the countermovement jump (CMJ) to assess training adaptations in American collegiate football athletes through examining weekly changes in CMJ performance over the course of two 4-week periodized training blocks (8 weeks total), and 5) to examine the effect of acute fatigue on CMJ performance in American football athletes. The first study from this line of research quantified the physical demands of American collegiate football by position groups and found significant differences in both running based and non-running based training load metrics. In addition, the first study utilized a principal component analysis to determine 5 'principal' components that explain approximately 81% of the variance within the data. The second study utilized a univariate analysis and found significant changes in CMJ performance due the effect of time with significant improvements in CMJ 'strategy' variables over the training period. Finally, the third study used effects sizes to illustrate a larger magnitude of change in CMJ 'strategy' variables than CMJ 'output' variables due to effect of acute fatigue. Results from studies 2 and 3 suggest the importance of monitoring CMJ strategy variables when monitoring training adaptations and fatigue in American collegiate football athletes. This line of research provides practitioners with a systematic framework through which they can develop and implement evidence-based sport preparation programs within their own organizational context. In addition, this line of research provides practitioners with recommendations for which metrics to monitor when tracking training load in American collegiate football using integrated microtechnology. Finally, this line of research demonstrates how to assess training adaptations and fatigue using the CMJ within the sport of American collegiate football, while providing an empirical base through which the selection of CMJ variables can take place. Collectively, this line of research uses scientific principles and theory to extend the current literature in American collegiate football, while providing practitioners with a guide to athlete monitoring within the sport. / Doctor of Philosophy / American football is one the most popular sports in the United States. Despite its popularity, there is limited research using scientific principles and theories to examine ways to most effectively monitor the sport. Broadly, athlete monitoring refers to the process of providing informational feedback from the athlete to practitioners. This allows practitioners to make decisions informed by data. Therefore, this line of research (i.e. dissertation) aimed to use a variety of commonly used athlete monitoring tools to monitor American collegiate football athletes, while proposing a framework to guide in the development of an athlete monitoring program. This line of research consisted of a series of 3 studies. In study #1, it was found that integrated microtechnology units and heart rate sensors could be used to determine the physical demands of American collegiate football practice, as well as differences in the physical demands of practice by position group. In addition, a set of 5 training load constructs were found through which training load in American collegiate football athletes may be appropriately monitored. In study #2, it was found that countermovement jump (CMJ) strategy variables indicating how the jump occurred may provide more insight into strength and power training adaptations than CMJ output variables that indicate what occurred as a result of the jump in this highly trained athletic population. Finally, in study #3, it was found that CMJ strategy variables may be more sensitive to acute fatigue from a football-specific training session than CMJ output variables in American collegiate football athletes. Collectively, this research suggest that integrated microtechnology units, heart rate sensors, and the CMJ using a force testing platform may be used to monitor American collegiate football athletes. Moreover, this research suggests which variables to utilize when monitoring this population using these tools through the proposed athlete monitoring framework.

Microchannels have been used in electronics cooling and in air conditioning applications as condensers. Little study has been made in the application of microchannels in automotive heat exchangers, particularly the radiator. The presented research captures the need for the design improvement of radiator heat exchangers in heavy-duty vehicles in order to reduce aerodynamic drag and improve fuel economy. A method for analyzing an existing radiator is set forth including the needed parameters for effective comparisons of alternative designs. An investigation of microchannels was presented and it was determined that microchannels can improve the overall heat transfer of a radiator but this alone will not decrease the dimensions of the radiator. Investigations into improving the air-side heat transfer were considered and an improved fin design was found which allows a reduction in frontal area while maintaining heat transfer. The overall heat transfer of the design was improved from the original design by 7% well as 52% decrease in frontal area but at the cost of 300% increase in auxiliary power. The energy saved by a reduction in frontal area is not substantial enough to justify the increase of auxiliary power. The findings were verified through a computational fluid dynamic model to demonstrate the heat transfer and pressure drop of microchannel tubes. The results confirmed that heat transfer of microchannels does improve the thermal performance of the radiator but the pressure drop is such that the net benefit does not outweigh the operating cost. An additional CFD study of the new fin geometry and air-side heat transfer predictions was conducted. The results of the study confirmed the theoretical calculations for the fin geometry.

The primary objective of the presented research is to develop a class of integrated compact silicon diffractive sensors (CSDS) based on in-plane diffraction gratings. This class of sensors uses a silicon-on-insulator (SOI) substrate to limit costs, exploit established fabrication processes, enable integration of supporting electronics, and use the well-understood telecommunications wavelength of 1.55µm. Sensing is achieved by combining constant-diffraction-efficiency and highly-angularly-selective in-plane resonance-domain diffraction gratings. Detection is based on the diffraction efficiency of the highly angularly selective grating. In this research, the design processes for the constant-diffraction-efficiency and the highly angularly selective gratings are detailed. Grating designs are optimized with rigorous coupled-wave analysis (RCWA) and simulated with finite-difference time-domain (FDTD) analysis. Fabrication results are presented for the CSDS gratings. An inductively coupled plasma (ICP) Bosch etch process enables grating fabrication to within one percent of designed values with nearly vertical sidewalls. Experimental results are presented for individual CSDS gratings, the prototype sensor, and a prototype linear sensor array. The results agree well with simulation. The linear sensor array prototype demonstrates the intrinsic splitting mechanism and forms the basis of a 2-D sensor array. Finally, a toluene sensor was functionally demonstrated. The proof-of-concept device includes a polymer immobilization layer and microfluidic delivery of toluene. Toluene concentrations as low as 100ppm are measured, corresponding to a refractive index change of 3x10⁻⁴ RIU.

The marked increase in demand for miniaturized consumer products in a broad range of potential applications including medical, telecommunication, avionics, biotechnology and electronics is a result of advancements in miniaturization technologies. Consequently, engineering components are being drastically reduced in size. This coupled with the quest for higher quality components, has imposed more stringent requirements on manufacturing processes and materials used to produce micro components. Hence, the development of ultra precision manufacturing processes to fabricate micro-scale features in engineering products has become a focal point of recent academic and industrial research. However, much attention in the area of micro-manufacturing, especially micro-mechanical machining, has been devoted to building miniature machine tools with nanometer positioning resolution and sub-micron accuracy. There is lack of fundamental understanding of mechanical machining at the micro and nano scale. Specifically, basic understanding of chip formation mechanism, cutting forces, size-effect in specific cutting energy, and machined surface integrity in micro and nano scale machining and knowledge of how these process responses differ from those in macro-scale cutting are lacking. In addition, there is a lack of investigations of micro and nano scale cutting of common engineering materials such as aluminum alloys and ferrous materials. This thesis proposes to advance the understanding of machining at the micro and nano scale for common engineering alloys. This will be achieved through a series of systematic micro and nano cutting experiments. The effects of cutting conditions on the machining forces, chip formation and machined surface morphology in simple orthogonal micro-cutting of a ferrous, P20 mold steel (30 HRC), and a non-ferrous structural alloy, aluminum AL7075 (87 HRB), used in the mold making and rapid prototyping industry will be studied. The data will also be compared with data obtained from conventional macro-scale cutting. In addition, the applicability of conventional metal cutting theory to micro and nano cutting test data will be examined. The analysis will provide a better understanding of machining forces, chip formation, and surface generation in micro and nano scale cutting process and how it differs from macro-scale cutting.

The development of miniaturized technologies has become a global phenomenon that continues to make an impact across a broad range of applications that encompasses many diverse fields and industries including telecommunications, portable consumer electronics, defense, and biomedical. Subsequently this trend has caused more and more interest in the issues involved in the design, development, operation and analysis of equipment and processes for manufacturing micro components. One technology used to create these miniaturized components is micro end milling. The cutting forces of the micro end milling process provide vital information for the design, modeling, and control of the machining process. To gain an understanding of forces in micro end milling operations, a model of average chip thickness is derived and the differences between conventional end milling and micro end milling are enumerated. From the experimental results, empirical models for specific cutting constants were derived and compared the generally accepted forms for conventional end milling operations. These models provide a tool for the estimation of cutting forces in micro end milling.

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