All but the simplest physical systems contains mechanical joints. The behavior of these joints is sometimes the dominant factor in over all system behavior. The potential for occurence of microslip and macroslip normally makes the behavior of joints non-linear. Accurate modeling of joints requires a non-linear ramework. As clamping pressures are typically random ad variable, the behavior of the joints becomes random. Joint geometries are random along with other unknowns of the joints. Two different methods for measuring the energy dissipation are explained. In the experimental method, the energy dissipation of a non-linear joint is calculated from the slope of the envelope of the time response of acceleration. The simulation work is carried out by considering a smooth hysteresis model with the help of Matlab programming. Finally, the parameters are extracted for a specific non-linear system by comparing analytical and experimental results. / 0736988322

A novel technique of coupling near-field evanescent waves by means of variable period subwavelength gratings (1.2 ìm and 1.0 ìm), using a 1.55 ìm infrared semiconductor laser is presented for the use of an optical MEMS accelerometer. The subwavelength gratings were fabricated on both glass and silicon substrates respectively. Optical simulation of the subwavelength gratings was carried out to obtain the maximum coupling efficiency of the two subwavelength gratings; the grating thickness, grating width, and the grating separation were optimized. This was performed for both silicon and glass substrates. The simulations were used to determine the total system noise, including the noise generated from the germanium photodiode, sensitivity, and displacement detection resolution of the coupled subwavelength grating MEMS accelerometer. The coupled gratings were utilized as optical readout accelerometers. The spring/proof mass silicon accelerometer was fabricated using a four mask process, in which the structure was completed using two deep reactive ion etching (DRIE) processes. The designed serpentine spring styles determine the sensitivity of the accelerometer; when the springs are made longer or shorter, thicker or thinner, this directly attributes to the sensitivity of the device. To test function of the example of the devices, the accelerometer is placed on a platform, which permits displacement normal to the plane of the grating. The 1.550 ìm infrared laser is incident on the coupled subwavelength grating accelerometer device and the output intensity is measured using a geranium photodiode. As the platform is displaced, the grating separation between the two gratings changes and causes the output intensity to change. Using the coupled subwavelength grating simulations as a reference to the output intensity change with respect to gap, the mechanical and coupling sensitivity properties of as it relates to acceleration is presented.

Falls among the elderly population continue to be a growing concern in the healthcare industry and are marked by staggeringly high social and economic costs. The incidence of falls is known to increase with age, and currently the elderly population is growing at an astounding rate as baby-boomers are now entering this age group. Also, recovery following fall-related injuries decreases with increased age. These confounding factors currently make falls a very important area of research. Of the injuries typically seen in falls among the elderly, head injuries are one of the most debilitating. Death due to head trauma among the elderly is gaining national attention; head trauma is now considered the number one cause of death among elders who fall1. Among other technologies, medical helmets are often employed to protect against such injuries, but patient compliance with these helmets remains an issue. Current helmets use foams and cotton as padding, contributing to clumsy designs. Dilatent and honeycomb materials may be the future of this industry as their low weight and high efficacy per thickness make them ideal materials for thinner, lighter, less cumbersome head protection devices. This study outlines various modes of head injury and then highlights several head protection measures. The newer materials are tested using various methods to determine the most promising candidates for prototype designs. Next, three prototypes are assembled from the newer materials and compared directly based on the protection measures established. Finally, the top-performing prototype is compared against two existing medical helmets in a similar fashion. The results show that the best prototype significantly outperforms one of the existing medical helmets, and shows slight improvement over the other. These results establish the promise of these newer materials in the application of head protection devices.

Background: Physical inactivity has been consistently associated with numerous negative health outcomes that track from childhood into adulthood, making physical activity a special concern in the pediatric population. Dose-response studies are particularly useful when trying to understand the minimal and optimal amounts of physical activity needed to reduce the risk of negative health outcomes. Unfortunately, previous work within youth has relied on self-reported measures of physical activity, and this research does not provide a clear picture of the true relation between physical activity and health. Objectives: Manuscript 1. Describe the dose-response relation between dyslipidemia and moderate-to-vigorous physical activity (MVPA) in youth. Manuscript 2. Quantify the difference between self-reported and objectively measured MVPA in youth. Taken together, the overall objective of this thesis was to examine the dose-response relation between objectively measured MVPA and dyslipidemia in youth and determine how this may affect current Canadian physical activity guidelines. Methods: Both manuscripts used data from the U.S. National Health and Nutrition Examination Survey. Fractional polynomial regression modeling was used to fit the dose-response curves between MVPA and lipid/lipoprotein measurements. Regression analysis as well as a Bland-Altman plot was used to explain the discrepancy between self-reported and objective measures of MVPA. All analyses were completed using SAS statistical software. Results: Manuscript 1. Risks for high-risk HDL-cholesterol and triglyceride values decreased in a curvilinear manner with increasing minutes of MVPA. The greatest reduction in risk occurred within the first 30 min/d of MVPA. The relation between level of MVPA and LDL-cholesterol was unclear. Manuscript 2. The average youth over-reported their MVPA by ~30 min/d. The over-reporting was not mediated by basic demographic factors; however, the difference in reporting was systematic in nature such that inactive youth over-reported to the greatest extent. Conclusions: Manuscript 1. Youth need to accumulate 30 min/d of MVPA to greatly reduce their risk for dyslipidemia. Manuscript 2. Youth tend to over-report their daily MVPA by approximately 30 min/d. Combined, the results from this thesis suggest that physical activity recommendations for cardiovascular health in youth should suggest a minimum of 30 min/d of MVPA and preferred level of 60 min/d. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2009-09-07 08:48:03.896

No description available.

This thesis presents the design, implementation and fabrication for a 0.13μm interface to a capacitive MEMS accelerometer. By varying the number of amplifier slices used in concurrence based on different full scale input ranges, the analog circuitry power scales as the input range scales. Due to the oversampling nature of typical accelerometer front ends, for a full-scale input increase of N times, the analog circuitry power reduces by N2 times. The front end has two signal amplification stages, with the first stage power scaled. The chip is 1.15mmx1.15mm and implemented in a 0.13μm CMOS process. The design was packaged with the MEMS accelerometer chip inside a 44 pin CQFP. Measured results show an output rms noise of 63μVrms in a 100Hz bandwidth. The total analog circuitry power scales very linearly with different full scale ranges. A novel simple offset removal network is also shown and confirmed via measurement results.

This thesis presents the design, implementation and fabrication for a 0.13μm interface to a capacitive MEMS accelerometer. By varying the number of amplifier slices used in concurrence based on different full scale input ranges, the analog circuitry power scales as the input range scales. Due to the oversampling nature of typical accelerometer front ends, for a full-scale input increase of N times, the analog circuitry power reduces by N2 times. The front end has two signal amplification stages, with the first stage power scaled. The chip is 1.15mmx1.15mm and implemented in a 0.13μm CMOS process. The design was packaged with the MEMS accelerometer chip inside a 44 pin CQFP. Measured results show an output rms noise of 63μVrms in a 100Hz bandwidth. The total analog circuitry power scales very linearly with different full scale ranges. A novel simple offset removal network is also shown and confirmed via measurement results.

A Wearable Mobility Monitoring System (WMMS) can be an advantageous device for rehabilitation decision-making. This thesis presents the design and evaluation of a proof-of-concept WMMS that uses the BlackBerry Smartphone platform. A Java program was developed for the BlackBerry 9550, using the integrated tri-axial accelerometer, Global Positioning System sensor (GPS), CMOS digital video camera, and timer to identify change-of-state (CoS) among static states, dynamic states, small activity of daily living (ADL) movements, and car riding. Static states included sitting, lying, standing, and taking an elevator. Dynamic states included walking on level ground, walking on stairs, and walking on a ramp. Small activity of daily living movements included bathroom activities, working in the kitchen, and meal preparation. Following feature extraction from the sensor data, two decision trees were used to distinguish CoS and mobility activities. CoS identification subsequently triggered video recording for improved mobility context analysis during post-processing.

Functional electrical stimulation (FES) is a rehabilitative technology that can be used to improve walking in individuals with mobility impairments due to neurologic injury or disease. Feedback is essential for efficient FES-assisted walking. The overall goal of my project was to investigate external sensors to provide feedback for FES-assisted walking. The current study evaluated accelerometers, force sensitive resistors, segment orientation angles, and segment angular velocities to determine which were appropriate for determining the activation and deactivation of six major muscles used for walking. The results demonstrated that the segment orientation angles were the most appropriate sensors. Using the segment angle of the thigh, shank, and foot, the activation and deactivation times of the six muscles investigated could be determined within 6% of the step cycle. The shank segment angle performed the best for determining the activation and deactivation times when only one sensor was desired.

Submitted by Victor Manieri Schutzer null (victor_schutzer@hotmail.com) on 2018-04-05T01:19:20Z No. of bitstreams: 1 Dissertação completa - victor manieri schutzer.pdf: 2057859 bytes, checksum: 965ab65ab6bb0942e2639d8fdfbafe05 (MD5) / Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2018-04-05T12:41:58Z (GMT) No. of bitstreams: 1 schutzer_vm_me_bauru.pdf: 2057859 bytes, checksum: 965ab65ab6bb0942e2639d8fdfbafe05 (MD5) / Made available in DSpace on 2018-04-05T12:41:58Z (GMT). No. of bitstreams: 1 schutzer_vm_me_bauru.pdf: 2057859 bytes, checksum: 965ab65ab6bb0942e2639d8fdfbafe05 (MD5) Previous issue date: 2018-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A crescente mecanização na agricultura mundial foi acompanhada do aumento do número de acidentes e fez com que elevasse a preocupação com a saúde de seus operadores, já que tais trabalhadores estão expostos aos riscos que esse tipo de atividade proporciona. Alguns dos graves problemas que são gerados pelos equipamentos agrícolas é a alta vibração e ruído a que os operadores ficam expostos na sua jornada de trabalho. A vibração que atinge os trabalhadores pode ser considerada como um distúrbio, já que é responsável por grandes prejuízos à saúde do ser humano, estando diretamente relacionada com a fadiga do trabalhador. O ruído, considerado como um som indesejável, é outro problema gerado por máquinas motoras e responsável por lesão no aparelho auditivo e, até mesmo, por estresse psicofisiológico. Para o presente trabalho, analisou-se os riscos físicos que a vibração e o ruído causam em operadores de roçadoras motorizadas. Foram feitas análises de situações reais que os usuários deste tipo de máquina enfrentam no seu dia a dia de trabalho, para que se possa tirar conclusões da possibilidade de efeitos danosos. Para a pesquisa utilizou-se um acelerômetro de três eixos - HVM 100, marca Larson Davis, para mensurar a vibração captada pela mão do operador e um medidor de pressão sonora, marca Instrutherm, modelo DEC-460 para mensurar o ruído causado pela roçadora. Para a análise da vibração captada pela mão dos operadores foi utilizada a norma internacional ISO 5349 (2001) – Vibração Mecânica – Medição, Avaliação da Exposição Humana da Vibração Transmitida à Mão e Diretiva Europeia 2002/44/EC que estabelece os limites de exposição à vibração. As análises do ruído foram feitas a partir da Norma Regulamentadora – NR-15 – Atividades e Operações Insalubres. Os resultados de vibração e ruído apresentados em alguns testes ficaram acima do que estabelece a norma para que não haja prejuízo à saúde dos operadores deste tipo de equipamento durante uma exposição equivalente a uma jornada de trabalho de 8 horas. Além disso, mostra a importância do estudo, escolha e, principalmente, da correta utilização de EPI (Equipamento de Proteção Individual) para que minimize a vibração e o ruído que chegam ao organismo humano. É importante, ainda, a manutenção periódica dos equipamentos mecânicos para que os mesmos funcionem corretamente, evitando quebras das máquinas e danos aos operadores de tais equipamentos. / The increasing mechanization in world agriculture was accompanied by an increase in the number of accidents has caused concern about the health of its operators, as these workers are exposed to risks that this type of activity provides. Some of the serious problems that are generated by agricultural equipment are the high vibration and noise to which operators are exposed in their work. The vibration that affects the workers can be considered as a disorder, since it is responsible for major damages to the health of human beings, being directly related to worker fatigue. Noise, regarded as an unwanted sound, is another problem caused by motorized machines and responsible to hearing damage and even to psychophysiological stress. For this study, a physical risks analysis was made. So it is possible to determine the damage that vibration and noise can cause in motorized brushcutter’s operators. Real situations of the daily work that these users go through were analyzed, so that conclusions can be made of the possibility of harmful effects. For the research, an accelerometer of three axes - HVM 100, Larson Davis brand, was used to measure the vibration captured by the hand of the operator and a sound pressure meter, Instrutherm brand model DEC-460, was used to measure the noise caused by brushcutters. For the vibration analysis captured by the hand of the operators, the international standard ISO 5349 (2001) - Mechanical Vibration - Measurement and Evaluation of Human Exposure to Hand-Transmitted Vibration and the European Directive 2002/44/EC establishing the exposure limits for vibrations were used. Noise analysis was made based on the Regulatory Standard - NR-15 - Unhealthy Activities and Operations. The noise and vibration results in some tests were above the standard so that there is no damage to the health of the operators of such equipment during an exposure equivalent to an 8 hours working day. This also shows the importance of the study, choice and especially the proper use of PPE (Personal Protective Equipment) to minimize vibration and noise coming to the human body. The regular maintenance of mechanical equipment is also important so that they function properly, avoiding machinery breakages and damage to operators of such equipment.