Chan, Chun Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 77-84). / Abstracts in Chinese and English. / Acknowledgment: --- p.i / 摘要 --- p.ii / Abstract --- p.iv / List of Figure --- p.vi / List of Table --- p.viii / Content Page --- p.ix / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The Difficulties --- p.1 / Chapter 1.2 --- The Solution --- p.2 / Chapter 1.3 --- Goal of the Present Work --- p.2 / Chapter Chapter 2 --- Background and Methodology --- p.3 / Chapter 2.1 --- Hypertension Situation and Problems Around the World --- p.3 / Chapter 2.1.1 --- Blood Pressure Variability (BPV) --- p.4 / Chapter 2.2 --- Blood Pressure Measuring Methods --- p.5 / Chapter 2.2.1 --- Traditional Blood Pressure Meters --- p.6 / Chapter 2.2.2 --- Limitation of Commercial Blood Pressure Meters --- p.7 / Chapter 2.2.3 --- Pulse-Transit-Time (PTT) Based Blood Pressure Measuring Watch --- p.7 / Chapter 2.3 --- Wearable Body Sensors Network / System --- p.8 / Chapter 2.4 --- Current Status of e-Textile Garment --- p.9 / Chapter 2.4.1 --- Blood Pressure Measurement in e-Textile Garment --- p.13 / Chapter 2.5 --- Wearable Intelligent Sensors and System for e-Health (WISSH) --- p.15 / Chapter 2.5.1 --- "Monitoring, Connection and Display" --- p.15 / Chapter 2.5.2 --- Treatment --- p.16 / Chapter 2.5.3 --- Alarming --- p.17 / Chapter Chapter 3 --- "A h-Shirt to Non-invasive, Continuous Monitoring of Arterial Blood Pressure" --- p.18 / Chapter 3.1 --- Design and Inner Structure of h-Shirt --- p.18 / Chapter 3.1.1 --- Choose of e-Textile Material --- p.21 / Chapter 3.1.2 --- Design of ECG Circuit --- p.23 / Chapter 3.1.3 --- Design of PPG Circuit --- p.26 / Chapter 3.2 --- Blood Pressure Estimation Using Pulse-Transit-Time Algorithm --- p.28 / Chapter 3.2.1 --- Principal --- p.28 / Chapter 3.2.2 --- Equations --- p.29 / Chapter 3.2.3 --- Calibration --- p.29 / Chapter 3.3 --- Performance Tests on h-Shirt --- p.30 / Chapter 3.3.1 --- Test I: BP Measurement Accuracy --- p.30 / Chapter 3.3.2 --- Test I: Procedure and Protocol --- p.30 / Chapter 3.3.3 --- Test I-Results --- p.31 / Chapter 3.3.4 --- Test II: Continuality BP Estimation Performance --- p.31 / Chapter 3.3.5 --- Test II - Experiment Procedure and Protocol --- p.32 / Chapter 3.3.6 --- Test II - Experiment Result --- p.33 / Chapter 3.3.7 --- Test II 一 Discussion --- p.43 / Chapter 3.4 --- Follow-up Tests on ECG Circuit --- p.47 / Chapter 3.4.1 --- Problems --- p.47 / Chapter 3.4.2 --- Assumptions --- p.48 / Chapter 3.4.3 --- Experiment Protocol and Setup --- p.48 / Chapter 3.4.4 --- Experiment Results --- p.53 / Chapter 3.4.5 --- Discussion --- p.56 / Chapter Chapter 4: --- Hybrid Body Sensor Network in h-Shirt --- p.59 / Chapter 4.1 --- A Hybrid Body Sensor Network --- p.59 / Chapter 4.2 --- Biological Channel Used in h-Shirt --- p.60 / Chapter 4.3 --- Tests of Bio-channel Performance --- p.62 / Chapter 4.3.1 --- Experiment Protocol --- p.62 / Chapter 4.3.2 --- Results --- p.62 / Chapter 4.4 --- Discussion and Conclusion --- p.63 / Chapter Chapter 5: --- Conclusion and Suggestions for Future Works --- p.66 / Chapter 5.1 --- Conclusion --- p.66 / Chapter 5.1.1 --- Structure of h-Shirt --- p.66 / Chapter 5.1.2 --- Blood Pressure Estimating Ability of h-Shirt --- p.67 / Chapter 5.1.3 --- Tests and Amendments on h-Shirt ECG Circuit --- p.67 / Chapter 5.1.4 --- Hybrid Body Sensor Network in h-Shirt --- p.67 / Chapter 5.2 --- Suggestions for Future Work --- p.68 / Chapter 5.2.1 --- Further Development of Bio-channel Biological Model --- p.68 / Chapter 5.2.2 --- Positioning and Motion Sensing with h-Shirt --- p.69 / Chapter 5.2.3 --- Implementation of Updated Advance Technology into h-Shirt --- p.69 / Appendix: Non-invasive BP Measuring Device - Finometer --- p.71 / Reference: --- p.77

Orientador: Antônio Carlos Varela Saraiva / Banca : Vladir Wagner Ribas / Banca: José Benedito Oliveira Amorim / Resumo: Manutenções preventivas ou manutenções centradas na confiabilidade são ações sistemáticas, normalmente programadas, de controle e monitoramento, objetivando a redução de falhas com o aumento da usabilidade de equipamentos. Defeitos em máquinas, equipamentos ou em processos são fonte de prejuízos para clínicas e consultórios odontológicos, caso estes venham apresentar falhas de funcionamento ou simplesmente deixem de cumprir a função fim. Tais manutenções já são usufruídas pela indústria que visam programar paradas em equipamentos ou processos antes que falhas ocorram. Estas programações levam em consideração: a) o tempo que o equipamento ou processo deverá ficar parado para a execução de ajustes de variáveis de processo; b) substituição de componentes antes do fim da vida útil prevenindo dano pelo uso; c) planejamento da substituição do equipamento como um todo ou parte deste, no próprio local ou fora das instalações, conforme necessário. Falhas ocasionam algum impacto no faturamento em postos de serviço odontológico, pois geram retrabalho para o odontologista que tem parte de seu tempo que deveria ser produtivo, indisponível para o trabalho. Neste trabalho foi realizada uma pesquisa com diversos profissionais da área de odontologia, que utilizam equipamentos sujeitos a falhas. A partir da pesquisa foi identificado que compressores de ar são os equipamentos que mais geram prejuízos. Um equipamento embarcado de gestão, monitoramento e aviso foi projetado e desenvolvido para o ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Preventive maintenance or maintenance focused on reliability are systematic actions, usually scheduled, of control and monitoring, aiming to reduce failures with increasing usability of equipment. Defects in machines, equipment or processes are a source of damage to clinics and dental offices, if they are malfunctioning or simply fail to fulfill the purpose. Such maintenance is already used by the industry, which aims at scheduling stops at equipment or processes before failures occur. These schedules take into consideration: a) the time that the equipment or process should be stopped for the execution of adjustments of process variables; b) replacement of components before the end of the useful life preventing damage by the use; c) planning the replacement of the equipment as a whole or part thereof, on-site or off-site as required. Failures cause some impact on the billing at dental service stations, because they generate rework for the dentist who has part of his time that should be productive, unavailable for work. In this work a research was carried out with several dentistry professionals, who use equipment subject to failure. From the research it was identified that air compressors are the most damaging equipment. An embedded management, monitoring and warning equipment has been designed and developed to assist in the management of preventive maintenance of air compressors in clinics and dental offices / Mestre

As the demand for microprocessors is increasing with more and more consumers using integrated circuits in their daily life, the demand on the industry is increasing to ramp up production. In order to speed up the manufacturing processes, new and novel approaches are trying to change certain aspects of it. Microwaves have been tried as an alternative to conventional ovens in the curing of the polymers used as underfills and encapsulants in integrated circuits packages. Microwaves however being electromagnetic waves have non uniform energy distribution in different settings, causing burning or incomplete cure of polymers. In this study, we compare the two main types of microwaves proposed to perform the task of curing the polymers. To limit the study and obtain comparable results, both microwaves were limited to propagate in a single mode, TE10. The first is a closed microwave cavity using air as the propagation medium, and the second is an open microwave oven with a PTFE cavity that uses an evanescent field to provide energy. The open air cavity was studied with different orientations of a substrate placed inside it so as to find the best case scenario in the curing process. This scenario was then compared with the best case scenario found for a sample cured in an evanescent field. This comparison yielded results showing an advantage of the open microwave in maximum field present, thus leading to higher localized energy absorption and temperatures in the substrate, however this case also lead to a higher temperature gradient. The substrate cured in the closed microwave has a lower temperature gradient, but also a lower maximum field which leads to slower cure. In the TE10 mode therefore, a closed microwave has an overall advantage as the heating process is only slightly slower than that of an open cavity, but the temperature gradient in this case is significantly lower.

Abstract not available

Air-cooled condensers are routinely designed for a variety of applications, including residential air-conditioning systems. Recent attempts at improving the performance of these heat exchangers have included the consideration of microchannel tube, multilouver fin heat exchangers instead of the more conventional round tube-plate fin designs. In most packaged air-conditioning systems, however, the condenser surrounds the compressor and other auxiliary parts in an outdoor unit, with an induced draft fan at the top of this enclosure. Such a configuration results in significant mal-distribution of the air flow arriving at the condenser, and leads to a decrease in performance. This work addresses the issue of mal-distribution by adapting the air-side geometry to the expected air flow distribution. A microchannel tube, multilouver fin condenser is first designed to transfer the desired heat rejection load for an air-conditioning system under uniform air flow conditions. Tube-side pass arrangements, tube dimensions, and fin and louver geometry are varied to arrive at a minimum mass, 2.54 kg condenser that delivers the desired heat load of 14.5 kW. The design model is then used to predict the performance of the condenser for a variety of air flow distributions across the heat exchanger. It is found that for a 50% air flow mal-distribution, the required condenser mass increases to 2.73 kg. The air-side geometry (fin density and height) of the condenser is then systematically changed to optimally distribute the air-side surface area across the condenser to best address the mal-distributed air flow. It is found that linear fin density and height variations from the mean value of 40% and 20%, respectively, keeping the mean fin density and height the same, reduce the required condenser mass to 2.65 kg even for this mal-distributed air-flow case. The influence of geometry variations on heat transfer coefficients, fan power and other performance measures is discussed in detail to guide the judicious choice of surface area and tube-side flow area allocations for any potential air flow mal-distribution. The results from this study can be used for the design of air-cooled condensers under realistic flow conditions.

Enhanced Finned-Tube Condenser Design and Optimization Susan W. Stewart 173 pages Directed by Dr. Sam V. Shelton Finned-tube heat exchangers are widely used in space conditioning systems, as well as any other application requiring heat exchange between liquids and gases. Their most widespread use is in residential air conditioning systems. Residential systems dictate peak demand on the U.S. national grid, which occurs on the hot summer afternoons, and thereby sets the expensive infrastructure requirement of the nations power plant and electrical distribution system. In addition to peak demand, residential air conditioners are major energy users that dominate residential electrical costs and environmental impact. The only significant opportunity for electrical power use reduction of residential air conditioners is in technology improvement of the finned-tube heat exchangers, i.e., condenser and evaporator coils. With the oncoming redesign of these systems in the next five years to comply with the regulatory elimination of R-22 used in residential air conditioners today, improvement in the design technology of these systems is timely. An air conditioner condenser finned-tube coil design optimization methodology is derived and shown to lead to improved residential air conditioner efficiency at fixed equipment cost. This nonlinear optimization of the 14 required design parameters is impractical by systematic experimental testing and iteration of tens of thousands condenser coils in an air conditioning system. The developed methodology and results can be used in the redesign of residential systems for the new mandated environmentally friendly refrigerants and to meet increasing regulatory minimum system efficiencies. Additionally, plain fins and augmented fins, (louvered), are compared using the developed model and optimization scheme to show the effect of the augmentation on system performance. Furthermore, an isolated condenser model was developed using condenser entropy generation minimization as the figure of merit to minimize the model complexity and computation time. Isolated model optimizations are compared with the system model optimum designs.

A simplified computational fluid dynamics and heat transfer (CFD-HT) model of an electronics enclosure was developed. The compact model was based on a server simulator, which dissipates a variable amount of heat at an adjustable air flow rate. Even though a server simulator does not accurately represent the geometry of an actual electronics enclosure, the modeling of such a unit deals with many of the same issues as the modeling of actual enclosures. Even at the server simulator level, a disparity in length scales prevents detailed modeling of intricate components most notably grilles, fins, and fans. Therefore, a compact model for each of these components was developed. Fan performance curves were determined experimentally for varying fan rotational speeds. In addition, component pressure drop characteristics were found experimentally for grilles and fin banks, and these empirical relationships were applied to the model as well. To determine the validity of the simplifications employed in the model, experimental outlet temperature and velocity measurements were taken to compare to those provided by the CFD-HT simulations.

The study aimed to identify leading practices to promote environmentally friendly and efficient efforts in surgical healthcare. Despite widespread enthusiasm for going green in the U.S. economy, little information is available to inform the medical community on the effort. We explore safe and efficient strategies for hospitals and healthcare providers to protect the environment while delivering high-quality care. As part of the study design, we performed a systematic review of the literature using relevant Pubmed search terms and surveyed a panel of hospital managers and CEOs of healthcare organizations pursuing green initiatives. Recommendations were itemized and reviewed with each panelist for a consensus agreement. At the end, we identified forty-three published articles and obtained interview data from the 7-member expert panel. Five green recommendations for surgical practices were identified: (1) OR Waste Reduction and Segregation; (2) Environmentally Preferable Purchasing; (3) Energy Consumption Management; (4) Pharmaceutical Waste Management; (5) Reprocessing of Single Use Medical Devices. We concluded that the medical community has a large opportunity to implement green practices in surgical units. These practices can have significant benefits to both the healthcare community and the environment.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

No description available.