Resonant power conversion topologies for inductive charging of electrical vehicle batteries

This thesis is concerned with inductive charging of electric vehicle batteries. Rectified power form the 50/60 Hz utility feeds a dc-ac converter which delivers high-frequency ac power to the electric vehicle inductive coupling inlet. The inlet configuration has been defined by the Society of Automotive Engineers in Recommended Practice J-1773. This thesis studies converter topologies related to the series resonant converter. When coupled to the vehicle inlet, the frequency-controlled series-resonant converter results in a capacitively-filtered series-parallel LCLC (SP-LCLC) resonant converter topology with zero voltage switching and many other desirable features. A novel time-domain transformation analysis, termed Modal Analysis, is developed, using a state variable transformation, to analyze and characterize this multi-resonant fourth-orderconverter. Next, Fundamental Mode Approximation (FMA) Analysis, based on a voltage-source model of the load, and its novel extension, Rectifier-Compensated FMA (RCFMA) Analysis, are developed and applied to the SP-LCLC converter. The RCFMA Analysis is a simpler and more intuitive analysis than the Modal Analysis, and provides a relatively accurate closed-form solution for the converter behavior. Phase control of the SP-LCLC converter is investigated as a control option. FMA and RCFMA Analyses are used for detailed characterization. The analyses identify areas of operation, which are also validated experimentally, where it is advantageous to phase control the converter. A novel hybrid control scheme is proposed which integrates frequency and phase control and achieves reduced operating frequency range and improved partial-load efficiency. The phase-controlled SP-LCLC converter can also be configured with a parallel load and is an excellent option for the application. The resulting topology implements soft-switching over the entire load range and has high full-load and partial-load efficiencies. RCFMA Analysis is used to analyze and characterize the new converter topology, and good correlation is shown with experimental results. Finally, a novel single-stage power-factor-corrected ac-dc converter is introduced, which uses the current-source characteristic of the SP-LCLC topology to provide power factor correction over a wide output power range from zero to full load. This converter exhibits all the advantageous characteristics of its dc-dc counterpart, with a reduced parts count and cost. Simulation and experimental results verify the operation of the new converter.

Electrical machine characterisation and analysis for renewable energy applications

There has been an increased use of the Doubly-Fed Induction Machine (DFIM) in ac drive applications in recent times, particularly in the field of renewable energy systems and other high power variable-speed drives. The DFIM is widely regarded as the optimal generation system for both onshore and offshore wind turbines and has also been considered in wave power applications. Wind power generation is the most mature renewable technology. However, wave energy has attracted a large interest recently as the potential for power extraction is very significant. Various wave energy converter (WEC) technologies currently exist with the oscillating water column (OWC) type converter being one of the most advanced. There are fundemental differences in the power profile of the pneumatic power supplied by the OWC WEC and that of a wind turbine and this causes significant challenges in the selection and rating of electrical generators for the OWC devises. The thesis initially aims to provide an accurate per-phase equivalent circuit model of the DFIM by investigating various characterisation testing procedures. Novel testing methodologies based on the series-coupling tests is employed and is found to provide a more accurate representation of the DFIM than the standard IEEE testing methods because the series-coupling tests provide a direct method of determining the equivalent-circuit resistances and inductances of the machine. A second novel method known as the extended short-circuit test is also presented and investigated as an alternative characterisation method. Experimental results on a 1.1 kW DFIM and a 30 kW DFIM utilising the various characterisation procedures are presented in the thesis. The various test methods are analysed and validated through comparison of model predictions and torque-versus-speed curves for each induction machine. Sensitivity analysis is also used as a means of quantifying the effect of experimental error on the results taken from each of the testing procedures and is used to determine the suitability of the test procedures for characterising each of the devices. The series-coupling differential test is demonstrated to be the optimum test. The research then focuses on the OWC WEC and the modelling of this device. A software model is implemented based on data obtained from a scaled prototype device situated at the Irish test site. Test data from the electrical system of the device is analysed and this data is used to develop a performance curve for the air turbine utilised in the WEC. This performance curve was applied in a software model to represent the turbine in the electro-mechanical system and the software results are validated by the measured electrical output data from the prototype test device. Finally, once both the DFIM and OWC WEC power take-off system have been modeled succesfully, an investigation of the application of the DFIM to the OWC WEC model is carried out to determine the electrical machine rating required for the pulsating power derived from OWC WEC device. Thermal analysis of a 30 kW induction machine is carried out using a first-order thermal model. The simulations quantify the limits of operation of the machine and enable thedevelopment of rating requirements for the electrical generation system of the OWC WEC. The thesis can be considered to have three sections. The first section of the thesis contains Chapters 2 and 3 and focuses on the accurate characterisation of the doubly-fed induction machine using various testing procedures. The second section, containing Chapter 4, concentrates on the modelling of the OWC WEC power-takeoff with particular focus on the Wells turbine. Validation of this model is carried out through comparision of simulations and experimental measurements. The third section of the thesis utilises the OWC WEC model from Chapter 4 with a 30 kW induction machine model to determine the optimum device rating for the specified machine. Simulations are carried out to perform thermal analysis of the machine to give a general insight into electrical machine rating for an OWC WEC device.

Vulnerability and adaptation to climate change in Guam – a case-study of the perceptions, attitudes, behaviors, and knowledge of a small rural community towards their watershed

This thesis argues that examining the attitudes, perceptions, behaviors, and knowledge of a community towards their specific watershed can reveal their social vulnerability to climate change. Understanding and incorporating these elements of the human dimension in coastal zone management will lead to efficient and effective strategies that safeguard the natural resources for the benefit of the community. By having healthy natural resources, ecological and community resilience to climate change will increase, thus decreasing vulnerability. In the Pacific Ocean, climate and SLR are strongly modulated by the El Niño Southern Oscillation. SLR is three times the global average in the Western Pacific Ocean (Merrifield and Maltrud 2011; Merrifield 2011). Changes in annual rainfall in the Western North Pacific sub‐region from 1950-2010 show that islands in the east are getting much less than in the past, while the islands in the west are getting slightly more rainfall (Keener et al. 2013). For Guam, a small island owned by the United States and located in the Western Pacific Ocean, these factors mean that SLR is higher than any other place in the world and will most likely see increased precipitation. Knowing this, the social vulnerability may be examined. Thus, a case-study of the community residing in the Manell and Geus watersheds was conducted on the island of Guam. Measuring their perceptions, attitudes, knowledge, and behaviors should bring to light their vulnerability to climate change. In order to accomplish this, a household survey was administered from July through August 2010. Approximately 350 surveys were analysed using SPSS. To supplement this quantitative data, informal interviews were conducted with the elders of the community to glean traditional ecological knowledge about perceived climate change. A GIS analysis was conducted to understand the physical geography of the Manell and Geus watersheds. This information about the human dimension is valuable to CZM managers. It may be incorporated into strategic watershed plans, to better administer the natural resources within the coastal zone. The research conducted in this thesis is the basis of a recent watershed management plan for the Guam Coastal Management Program (see King 2014).

A MEMETIC/PARTICIPATORY APPROACH FOR CHANGING SOCIAL BEHAVIORS AND PROMOTING ENVIRONMENTAL STEWARDSHIP IN JALISCO, MEXICO

This dissertation addressed the issue of sustainable development at the level of individual behaviors. Environmental perceptions were obtained from people living around the biosphere reserve Chamela-Cuixmala in Jalisco, Mexico. Several environmental issues were identified by the people, such as garbage and grey water on the streets, burning plastics, and the lack of usage of recreational areas. All these issues could be addressed with a change in behavior by the villagers. Familiarization activities were conducted to gain people's trust in order to conduct a community forum. These activities included giving talks to school children and organizing workshops. Four different methodologies were generated using memetics and participation to test which would ameliorate those environmental issues identified by the people through a change in behavior. The methodologies were 1) Memes; 2) Participation and Memes; 3) Participation; 4) Neither Participation nor Memes. A meme is an idea expressed within a linguistic structure or architecture that provides it with self-disseminating and self-protecting characteristics within and among the minds of individuals congruent with their values, beliefs and filters. Four villages were chosen as the treatments, and one as the control, for a total of five experimental villages. A different behavior was addressed in each treatment village (garbage, grey-water, burning plastics, recreation.) A nonequivalent control-group design was established. A pretest was conducted in all five villages; the methodologies were tested in the four treatment villages; a posttest was conducted on the five villages. The pretest and posttest consisted in measuring sensory specific indicators which are manifestations of behavior that can either be seen, smelled, touched, heard or tasted. Statistically significant differences in behavior from the control were found for two of the methodologies 1) Memes (p=0.0403) and 2) Participation and Memes (p=0.0064). For the methodologies of 3) Participation alone and 4) Neither, the differences were not significant (p=0.8827, p=0.5627 respectively). When using memes, people's behavior improved when compared to the control. Participation alone did not generate a significant difference. Participation aided in the generation of the memes. Memetics is a tool that can be used to establish a linkage between human behavior and ecological health.

Exact analytical expressions for the potential of electrical double layer interactions for a sphere-plate system.

Exact, closed-form analytical expressions are presented for evaluating the potential energy of electrical double layer (EDL) interactions between a sphere and an infinite flat plate for three different types of interactions: constant potential, constant charge, and an intermediate case as given by the linear superposition approximation (LSA). By taking advantage of the simpler sphere-plate geometry, simplifying assumptions used in the original Derjaguin approximation (DA) for sphere-sphere interaction are avoided, yielding expressions that are more accurate and applicable over the full range of κa. These analytical expressions are significant improvements over the existing equations in the literature that are valid only for large κa because the new equations facilitate the modeling of EDL interactions between nanoscale particles and surfaces over a wide range of ionic strength.

Plasmon-induced electrical conduction in molecular devices.

Metal nanoparticles (NPs) respond to electromagnetic waves by creating surface plasmons (SPs), which are localized, collective oscillations of conduction electrons on the NP surface. When interparticle distances are small, SPs generated in neighboring NPs can couple to one another, creating intense fields. The coupled particles can then act as optical antennae capturing and refocusing light between them. Furthermore, a molecule linking such NPs can be affected by these interactions as well. Here, we show that by using an appropriate, highly conjugated multiporphyrin chromophoric wire to couple gold NP arrays, plasmons can be used to control electrical properties. In particular, we demonstrate that the magnitude of the observed photoconductivity of covalently interconnected plasmon-coupled NPs can be tuned independently of the optical characteristics of the molecule-a result that has significant implications for future nanoscale optoelectronic devices.

Mechanical constraints enhance electrical energy densities of soft dielectrics

Thesis

HIV/AIDS-related institutional mistrust among multiethnic men who have sex with men: effects on HIV testing and risk behaviors.

OBJECTIVE: To investigate relationships between institutional mistrust (systematic discrimination, organizational suspicion, and conspiracy beliefs), HIV risk behaviors, and HIV testing in a multiethnic sample of men who have sex with men (MSM), and to test whether perceived susceptibility to HIV mediates these relationships for White and ethnic minority MSM. METHOD: Participants were 394 MSM residing in Central Arizona (M age = 37 years). Three dimensions of mistrust were examined, including organizational suspicion, conspiracy beliefs, and systematic discrimination. Assessments of sexual risk behavior, HIV testing, and perceived susceptibility to HIV were made at study entry (T1) and again 6 months later (T2). RESULTS: There were no main effects of institutional mistrust dimensions or ethnic minority status on T2 risk behavior, but the interaction of systematic discrimination and conspiracy beliefs with minority status was significant such that higher levels of systematic discrimination and more conspiracy beliefs were associated with increased risk only among ethnic minority MSM. Higher levels of systematic discrimination were significantly related to lower likelihood for HIV testing, and the interaction of organizational suspicion with minority status was significant such that greater levels of organizational suspicion were related to less likelihood of having been tested for HIV among ethnic minority MSM. Perceived susceptibility did not mediate these relationships. CONCLUSION: Findings suggest that it is important to look further into the differential effects of institutional mistrust across marginalized groups, including sexual and ethnic minorities. Aspects of mistrust should be addressed in HIV prevention and counseling efforts.

Breech delivery and birth‐related behaviors in wild mantled howling monkeys

The breech birth of an infant mantled howling monkey was observed on February 12, 1990. The mother assisted the successful delivery by pulling on the infant's tail and hindleg. No other members of the social group attended the mother or demonstrated any interest in the birth process. Copyright © 1991 Wiley‐Liss, Inc., A Wiley Company

The professionalism disconnect: do entering residents identify yet participate in unprofessional behaviors?

BACKGROUND: Professionalism has been an important tenet of medical education, yet defining it is a challenge. Perceptions of professional behavior may vary by individual, medical specialty, demographic group and institution. Understanding these differences should help institutions better clarify professionalism expectations and provide standards with which to evaluate resident behavior. METHODS: Duke University Hospital and Vidant Medical Center/East Carolina University surveyed entering PGY1 residents. Residents were queried on two issues: their perception of the professionalism of 46 specific behaviors related to training and patient care; and their own participation in those specified behaviors. The study reports data analyses for gender and institution based upon survey results in 2009 and 2010. The study received approval by the Institutional Review Boards of both institutions. RESULTS: 76% (375) of 495 PGY1 residents surveyed in 2009 and 2010 responded. A majority of responders rated all 46 specified behaviors as unprofessional, and a majority had either observed or participated in each behavior. For all 46 behaviors, a greater percentage of women rated the behaviors as unprofessional. Men were more likely than women to have participated in behaviors. There were several significant differences in both the perceptions of specified behaviors and in self-reported observation of and/or involvement in those behaviors between institutions.Respondents indicated the most important professionalism issues relevant to medical practice include: respect for colleagues/patients, relationships with pharmaceutical companies, balancing home/work life, and admitting mistakes. They reported that professionalism can best be assessed by peers, patients, observation of non-medical work and timeliness/detail of paperwork. CONCLUSION: Defining professionalism in measurable terms is a challenge yet critical in order for it to be taught and assessed. Recognition of the differences by gender and institution should allow for tailored teaching and assessment of professionalism so that it is most meaningful. A shared understanding of what constitutes professional behavior is an important first step.

Computer vision tools for low-cost and noninvasive measurement of autism-related behaviors in infants.

The early detection of developmental disorders is key to child outcome, allowing interventions to be initiated which promote development and improve prognosis. Research on autism spectrum disorder (ASD) suggests that behavioral signs can be observed late in the first year of life. Many of these studies involve extensive frame-by-frame video observation and analysis of a child's natural behavior. Although nonintrusive, these methods are extremely time-intensive and require a high level of observer training; thus, they are burdensome for clinical and large population research purposes. This work is a first milestone in a long-term project on non-invasive early observation of children in order to aid in risk detection and research of neurodevelopmental disorders. We focus on providing low-cost computer vision tools to measure and identify ASD behavioral signs based on components of the Autism Observation Scale for Infants (AOSI). In particular, we develop algorithms to measure responses to general ASD risk assessment tasks and activities outlined by the AOSI which assess visual attention by tracking facial features. We show results, including comparisons with expert and nonexpert clinicians, which demonstrate that the proposed computer vision tools can capture critical behavioral observations and potentially augment the clinician's behavioral observations obtained from real in-clinic assessments.

Patient beliefs and behaviors about genomic risk for type 2 diabetes: Implications for prevention

Copyright © Taylor & Francis Group, LLC 2015.Type 2 diabetes is a major health burden in the United States, and population trends suggest this burden will increase. High interest in, and increased availability of, testing for genetic risk of type 2 diabetes presents a new opportunity for reducing type 2 diabetes risk for many patients; however, to date, there is little evidence that genetic testing positively affects type 2 diabetes prevention. Genetic information may not fit patients illness representations, which may reduce the chances of risk-reducing behavior changes. The present study aimed to examine illness representations in a clinical sample who are at risk for type 2 diabetes and interested in genetic testing. The authors used the Common Sense Model to analyze survey responses of 409 patients with type 2 diabetes risk factors. Patients were interested in genetic testing for type 2 diabetes risk and believed in its importance. Most patients believed that genetic factors are important to developing type 2 diabetes (67%), that diet and exercise are effective in preventing type 2 diabetes (95%), and that lifestyle changes are more effective than drugs (86%). Belief in genetic causality was not related to poorer self-reported health behaviors. These results suggest that patients interest in genetic testing for type 2 diabetes might produce a teachable moment that clinicians can use to counsel behavior change.

The Application of an Exogenous Linear and Radial Electrical Field to an In Vitro Chronic Diabetic Ulcer Model for Evaluation as a Potential Treatment

Chronic diabetic ulcers affect approximately 15% of patients with diabetes worldwide. Currently, applied electric fields are being investigated as a reliable and cost-effective treatment. This in vitro study aimed to determine the effects of a constant and spatially variable electric field on three factors: endothelial cell migration, proliferation, and angiogenic gene expression. Results for a constant electric field of 0.01 V demonstrated that migration at short time points increased 20-fold and proliferation at long time points increased by a factor of 1.40. Results for a spatially variable electric field did not increase directional migration, but increased proliferation by a factor of 1.39 and by a factor of 1.55 after application of 1.00 V and 0.01 V, respectively. Both constant and spatially variable applied fields increased angiogenic gene expression. Future research that explores a narrower range of intensity levels may more clearly identify the optimal design specifications of a spatially variable electric field.

Polymer waveguide and VCSEL array multi-physics modelling for OECB based optical backplanes [opto-electrical circuit boards]

The deployment of OECBs (opto-electrical circuit boards) is expected to make a significant impact in the telecomm switches arena within the next five years. This will create optical backplanes with high speed point-to-point optical interconnects. The crucial aspect in the manufacturing process of the optical backplane is the successful coupling between VCSEL (vertical cavity surface emitting laser) device and embedded waveguide in the OECB. The results from a thermo-mechanical analysis are being used in a purely optical model, which solves optical energy and attenuation from the VCSEL aperture into, and then through, the waveguide. Results from the modelling are being investigated using DOE analysis to identify packaging parameters that minimise misalignment. This is achieved via a specialist optimisation software package. Results from the thermomechanical and optical models are discussed as are experimental results from the DOE.

Comparative wetting behavior of Sn-0.7Cu and Sn-0.7Cu-0.3Ni solders on Cu and Ni substrates

Electronic packaging industries are now in great challenge to find a suitable lead-free solder as an interconnection material to replace the conventional SnPb solders. Many solders such as SnCu, SnAg, SnAgCu, SnZn, SnBi have already been proposed as the replacement but none of them has reached the physical and metallurgical properties similar to the SnPb solder. However, wetting is one of the basic problems that make the lead-free solder inferior as compared to the SnPb solder. Therefore, alloying with the help of third, fourth or fifth element is the researchers' interest to improve the wetting behavior of lead-free solders. This paper describes the comparative wetting behavior of Sn-0.7Cu and Sn-0.7Cu-0.3Ni solders on Cu and Ni substrates. Wetting balance tests were performed to assess the wetting behaviors. Three different commercial fluxes namely no-clean (NC), non-activated (R) and water soluble organic acid (WS)fluxes were used to assess the wettability for three solder bath temperatures. It was found that Sn0.7Cu-03Ni solder exhibits better wettability on Cu substrate for NC and WS fluxes whereas reverse results were found for R-type flux. In the case of Ni substrate, Sn-0.7Cu-0.3Ni solder showed better wetting behavior compared to the well-known Sn-0.7Cu solder. Among the three fluxes, R-type flux showed the worst performance. Very large contact angles were documented for both solders with this flux. Higher solder bath temperature lowered the contact angles, increased the wetting forces and enhanced the wettability. Computer modeling of wetting balance test revealed that both the wetting force and meniscus height are inversely proportional to the contact angles. Modeling results also reveal that increase in solder bath depths and radiuses do not affect significantly on the wetting behavior.