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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.
51

The Coordination of Breathing and Swallowing Across the Human Lifespan: Implications for Neural Control

Kelly, Bronwen Noreen January 2006 (has links)
Our understanding of the neural control of breathing-swallowing coordination (BSC) is largely unclear. Although brainstem control is undoubtedly predominant, this research investigated the hypothesis that the cortex becomes increasingly influential in BSC between birth and adulthood. The main paradigm used to test this primary hypothesis was a comparison of BSC in conditions along a continuum of volitional through non-volitional swallowing on the basis of a decreasing level of cortical activation along this continuum. Voluntarily-initiated swallows during wakefulness were at one end of the continuum and reflexively-initiated swallows during sleep were at the other extreme. Non-volitional wakeful swallows were considered between these two conditions. The BSC of ten infants between birth and 1 year of age and twenty adults between the ages of 20 and 75 years was recorded using non-invasive time-locked recording methods. In order to apply the 'continuum-of-volition' paradigm to swallowing conditions in infants, BSC was monitored during nutritive (breast- or bottle-feeding), non-nutritive wake, and sleep swallows. Infants were monitored longitudinally to determine whether maturation of the cortex and corticobulbar tracts during the first year of life influenced the patterns of BSC. In adults, BSC was monitored during three non-nutritive conditions: volitional, spontaneous wake, and sleep conditions. Post-swallow expiration was found to be predominant in all conditions for all participants at all ages. In addition, the infant results revealed that nutritive BSC matured during the first year of life and differed to non-nutritive wakeful BSC, particularly in the first 2 months of life. Non-nutritive wakeful and sleep BSC did not differ from one another. In summary, the infant results support increasing cortical input into volitional nutritive BSC, an early impact of feeding on BSC, and no difference between BSC when asleep and non-volitional non-nutritive swallows when awake. The results obtained from adults revealed that irrespective of the level of arousal, volitional BSC is different to non-volitional BSC. These results imply that cortical influence on BSC is limited to conditions in which swallowing is voluntarily initiated. The combined interpretation of infant and adult results suggest that cortical influence over BSC, although increasing with maturation, is limited to the volitional swallowing conditions of feeding in infants and during non-nutritive but volitional swallows in adults. From this, it can be deduced that the most likely cortical sites involved in BSC are those involved in the voluntary initiation or planning of swallowing. Infant and adult swallowing apnoea duration (SAD) was also compared across all of the above conditions. SAD was influenced by feeding throughout the first year of life but was not influenced by level of arousal at any stage in the first year or in adulthood. Also, SAD did not change with age in any swallowing condition during infancy. However, comparison of non-nutritive wake SAD across the lifespan revealed that SAD of newborns and young adults is shorter than that of elderly adults, with no difference between consecutive age-groups: newborns, one-year-olds, and young adults. These results suggest SAD is largely mature at birth and impervious to descending suprabulbar influence. Finally, the effects of volitional swallowing and level of arousal on peak submental surface electromyography (SEMG) was investigated in adults. Like BSC, submental muscle activity was influenced only by volitional swallowing, being longer for volitional than non-volitional swallows without being influenced by level of arousal. Since peak submental SEMG activity represents a measure of relative hyolaryngeal excursion, these results suggest that the cortex has some degree of influence over this particular feature of pharyngeal-stage swallowing.
52

Adaptive optimization of intelligent flow control

Chiu, Kuan-Shiu January 1999 (has links)
No description available.
53

Geologic controls on reservoir quality of the Hunton and Viola limestones in the Leach Field, Jackson County, Kansas

Rennaker, Joshua Jay January 1900 (has links)
Master of Science / Department of Geology / Matthew W. Totten / The area of study for this project is the Leach Field, which is located in Jackson County, Kansas. Production in the Leach Field has historically been disappointing, with 388,787 barrels of oil being produced since the field’s discovery in 1963 (KGS, 2015). Production of the field has been highly variable, with only 20,568 barrels of oil being produced in the last 20 years. Economic and other concerns that have impacted production and production rates of the field include: low oil prices soon after its discovery, numerous changes of ownership, and lack of significant production infrastructure in the area. Stroke of Luck Energy & Exploration, LLC. has recently purchased the majority of the leases and wells in the Leach Field, and is reestablishing the field as a productive oil field. Plans include: washing down several plugged and abandoned wells, and drill new wells to increase production in the field. The goal of this study was to determine the major geologic factors controlling reservoir quality in the Hunton and Viola Limestone Formations in the Leach Field, so that a future exploration model can be developed to help increase and stabilize the field's overall production. This model was created by applying several testing methods including: well logging analysis, microscope analysis, and subsurface mapping. Based on these results it was determined that the quality of the reservoir rocks is controlled by the degree of dolomitizaiton in both formations. Reservoir quality is as important as structure in determining well productivity in the Leach Field.
54

Water Temperature Controls in the Sheepscot River, Maine

Gryga, Michele E January 2006 (has links)
Thesis advisor: Noah P. Snyder / The Sheepscot River watershed is 590 km2 located in mid-coast Maine. Two branches comprise the river: the main stem and the West Branch, which merge in North Whitefield before flowing into the Gulf of Maine. The Sheepscot River has an imposed form that is strongly influenced by the Norumberga Fault Zone and it flows through glacial deposits. The watershed has a temperate climate because of its location in mid-latitudes in the northern hemisphere. Water temperatures vary in the Sheepscot River over time and along the length of the river. The temporal and spatial variability of the river is due to air temperature, precipitation, discharge from the Palermo Fish Rearing Station, Long Pond, tree shade, confluence, and drainage area. Analysis of these hypothesized controls revolves around field water temperature measurements made between August 2005 and January 2006 and data collected from the North Whitefield gauging station. Supplementary digital spatial data from the Maine Geographic Information Systems data set were also used. Field measurements were taken at seven sites directly upstream and downstream of assumed controls. Climactic features of the watershed exert the main control over the entire river. Air temperature is the first order controls on water temperatures. Precipitation has some effect on water temperature but of less significance than air temperature. The river system has three areas that are affected by different combinations of the other controls: the upper main stem, the West Branch, and the lower main stem. Discharge from the Palermo Fish Rearing Station is the second major controlling factor of water temperature in the upper main stem. Its buffering effect is diluted downstream. Long Pond also affects the upper main stem by warming the water in the summer and cooling it in the winter. Drainage area explains variability in the West Branch and lower main stem. As drainage area increases downstream, water temperatures are controlled by more integrated factors. As a result of this the West Branch fluctuates more than the main stem because it has a smaller drainage area. Temperatures in the downstream reaches are less sensitive to any single control. Confluence and tree cover exert less influence over the system than other controls. / Thesis (BS) — Boston College, 2006. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Geology and Geophysics. / Discipline: College Honors Program.
55

Estudo da segurança em sistemas de controle metro-ferroviários. / Sem título em inglês

Camargo Júnior, João Batista 26 April 1996 (has links)
Este trabalho apresenta uma contribuição para a avaliação da segurança de sistemas críticos, especialmente os de controle metro-ferroviários, através de uma nova metodologia com enfoque primordial para a questão da completeza das suas especificações. Esta metodologia tem como base de aplicação o modelo de transição de estados, sendo seus critérios de verificação denotados através de expressões WFF acrescidas de funções típicas ao modelo utilizado. Este método de avaliação é aplicado a um controle metro-ferroviário típico, obtendo-se resultados promissores como ferramenta de análise de segurança de sistemas críticos. / This works presents a contribution to the evaluation of safety critical systems especially the metro-railways controls, through a new methodology with primordial focus in the completeness of their specifications. This methodology uses a state transition model to specify an application, with is verifications criteria denoted through WFF expressions added by typical functions of the used model. This method of evaluation is applied to a typical metro-railway control, showing promising results as an safety analysis tool for critical systems.
56

Quality effect of VER revisited: with special reference to Hong Kong's clothing export. / Quality effect of voluntary export restraint

January 1995 (has links)
by Lee Lai Shan, Cindy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 177-180). / LIST OF TABLES / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter CHAPTER 2 --- VOLUNTARY EXPORT RESTRAINT (VER)- AN OVERVIEW / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- What is a VER? --- p.9 / Chapter 2.3 --- Why is VER adopted? --- p.10 / Chapter 2.4 --- Characteristics of VER --- p.13 / Chapter 2.5 --- Conclusion --- p.16 / Chapter CHAPTER 3 --- LITERATURE REVIEW / Chapter 3.1 --- Introduction --- p.17 / Chapter 3.2 --- Theoretical Studies --- p.19 / Chapter 3.2.1 --- Heterogenous Product Approach / Chapter 3.2.2 --- Homogenous Product Approach / Chapter 3.3 --- Empirical Studies --- p.31 / Chapter 3.3.1 --- Heterogenous Product Approach / Chapter 3.3.2 --- Homogenous Product Approach / Chapter 3.4 --- Conclusion --- p.43 / Chapter CHAPTER 4 --- QUALITY EFFECT OF VER REVISITED / Chapter 4.1 --- Introduction --- p.44 / Chapter 4.2 --- The Model --- p.47 / Chapter 4.2.1 --- Assumptions / Chapter 4.2.2 --- Analysis / Chapter 4.3 --- Conclusion --- p.60 / Chapter CHAPTER 5 --- EMPIRICAL STUDY: MEASURING QUALITY ADJUSTMENT OF HONG KONG'S CLOTHING EXPORT UNDER VER / Chapter 5.1 --- Introduction --- p.65 / Chapter 5.2 --- Hong Kong's Clothing Export -- An Overview --- p.69 / Chapter 5.3 --- Multifibre Arrangement (MFA) and Its Relationship with Hong Kong's Clothing Export --- p.77 / Chapter 5.3.1 --- Multifibre Arrangement / Chapter 5.3.2 --- Multifibre Arrangement and Hong Kong / Chapter 5.4 --- Methodology --- p.84 / Chapter 5.5 --- Data --- p.92 / Chapter 5.6 --- Results and Analysis --- p.102 / Chapter 5.6.1 --- Aggregate Export of Clothing / Chapter 5.6.2 --- Restricted Vs Unrestricted Clothing / Chapter 5.6.3 --- Restricted Clothing by Types of Material / Chapter 5.6.4 --- Restricted Clothing by Types of Clothing / Chapter 5.7 --- Conclusion --- p.167 / Chapter CHAPTER 6 --- SUMMARY AND CONCLUSIONS --- p.170 / REFERENCES --- p.177 / APPENDIX 1 CLASSIFICATION OF QUOTA CATEGORIES IN HONGKONG-US AGREEMENT (1993) --- p.181 / APPENDIX 2 CLASSIFICATION OF QUOTA CATEGORIES IN HONGKONG-EC AGREEMENT (1993) --- p.183
57

Actuation, Control and Environment Setup for a bi-joint hydro-muscle driven leg structure

Zia, Amaid 27 April 2016 (has links)
About 74 million of the world population needs assistive leg devices on daily basis on account of some form of disability. Although the standard wheelchairs perform well on level ground terrains but they prove ineffective on soft ground and in crossing large obstacles. For dealing with the advance challenges of navigating the human environment a biped walker seems to a more suitable choice. The research presented here is focused on building and actuating a two-joint leg structure that is an integral part of ongoing leg-chair project in Popovic Labs. The project provides a proof of concept that how the synthetic hydro muscles (also developed by Popovic Labs) can be used for the control of large artificial limb joints. Here we discuss the designing, testing and corresponding refining of electronics design, actuation and control of the bi-joint hydro muscle actuated leg structure .We will also elaborate on the requirements, design, problems and refinement of some of the important mechanical components like Coupler/Decoupler and Force Multipliers.
58

Estudo da segurança em sistemas de controle metro-ferroviários. / Sem título em inglês

João Batista Camargo Júnior 26 April 1996 (has links)
Este trabalho apresenta uma contribuição para a avaliação da segurança de sistemas críticos, especialmente os de controle metro-ferroviários, através de uma nova metodologia com enfoque primordial para a questão da completeza das suas especificações. Esta metodologia tem como base de aplicação o modelo de transição de estados, sendo seus critérios de verificação denotados através de expressões WFF acrescidas de funções típicas ao modelo utilizado. Este método de avaliação é aplicado a um controle metro-ferroviário típico, obtendo-se resultados promissores como ferramenta de análise de segurança de sistemas críticos. / This works presents a contribution to the evaluation of safety critical systems especially the metro-railways controls, through a new methodology with primordial focus in the completeness of their specifications. This methodology uses a state transition model to specify an application, with is verifications criteria denoted through WFF expressions added by typical functions of the used model. This method of evaluation is applied to a typical metro-railway control, showing promising results as an safety analysis tool for critical systems.
59

Propagation of guided acoustic waves in composite media

Seale, Michael David 01 January 1996 (has links)
Composite materials are being more widely used today by aerospace, automotive, and a number of other commercial industries because of their advantages over conventional metals. Composites are finding applications ranging from bicycle frames to the proposed High-Speed Civil Transport (HSCT). Determining the response to a variety of damage mechanisms is necessary for a complete understanding of the total use environment of composite structures. The objective of the research presented here is to provide a method of quantifying the amount of damage in composite materials for a number of different damage scenarios. Components which have non-visible damage, but have degraded performance, are of interest. at this level of damage, the safety margin designed into the structure may be compromised.;Nondestructive Evaluation (NDE) is a field of measurement physics where energy is imparted to a material and information is obtained from observing how the energy interacts with the system. Many different forms of energy can be used to obtain useful information from these measurements: acoustic, thermal, x-ray, optical, and electromagnetic. Among the many various techniques available, ultrasonic Lamb waves offer a convenient method of evaluating these composite materials. as a material is damaged, the elastic parameters of the structure change. Since the Lamb wave velocity depends on these properties, an effective tool exists to monitor damage in composites by measuring the velocity of these waves. Additionally, Lamb wave measurements are beneficial because they can propagate over long distances and are sensitive to the desired in-plane elastic properties of the material.;Presented in this study are the results involving the investigation of a variety of damage mechanisms (fatigue, thermal, and thermal-mechanical) using the Lamb wave technique. Two fatigue studies were conducted which showed that the change in modulus and change in velocity of the Lamb wave squared follow the same general trend. The Lamb wave velocity was also observed to decrease with increasing crack density. For the thermal damage study, the results showed that the velocity of the lowest order symmetric Lamb mode dropped significantly for extended thermal damage. When the experimental results were compared to model calculations, good agreement was observed for both fatigue and thermal damage. Finally, for thermal-mechanical damage, it was found that the Lamb wave technique was also able to predict a local defect in a specimen, which was later found to have a large delamination zone.;The Lamb wave velocity is a quantitative measurement and it has been shown by this work to be an effective tool in monitoring different types of damage in composites. Since the Lamb wave velocity depends on a variety of material properties, an ideal technique exists to monitor composites as damage is incurred. With the continued development of damage assessment techniques such as the Lamb wave method, the safety of such structures can be assured.
60

Applications of pattern classification to time-domain signals

Bertoncini, Crystal Ann 01 January 2010 (has links)
Many different kinds of physics are used in sensors that produce time-domain signals, such as ultrasonics, acoustics, seismology, and electromagnetics. The waveforms generated by these sensors are used to measure events or detect flaws in applications ranging from industrial to medical and defense-related domains. Interpreting the signals is challenging because of the complicated physics of the interaction of the fields with the materials and structures under study. often the method of interpreting the signal varies by the application, but automatic detection of events in signals is always useful in order to attain results quickly with less human error. One method of automatic interpretation of data is pattern classification, which is a statistical method that assigns predicted labels to raw data associated with known categories. In this work, we use pattern classification techniques to aid automatic detection of events in signals using features extracted by a particular application of the wavelet transform, the Dynamic Wavelet Fingerprint (DWFP), as well as features selected through physical interpretation of the individual applications. The wavelet feature extraction method is general for any time-domain signal, and the classification results can be improved by features drawn for the particular domain. The success of this technique is demonstrated through four applications: the development of an ultrasonographic periodontal probe, the identification of flaw type in Lamb wave tomographic scans of an aluminum pipe, prediction of roof falls in a limestone mine, and automatic identification of individual Radio Frequency Identification (RFID) tags regardless of its programmed code. The method has been shown to achieve high accuracy, sometimes as high as 98%.

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