In this paper we discuss the inverse problem of the identification of mechanical stresses by measuring the deformation of an electric potential field in a so called differential strain gauge (D-DMS). We derive a mathematical model, where the forward operator is given in terms of an elliptic boundary value problem. Derivatives of the forward operator are considered and the solution of the inverse problem via a least-squares minimization is introduced. Here, the discretized problem is solved with the Gauss-Newton method. Numerical studies of practical interest are presented.

Water scarcity is one of the biggest issues we have to face as population and water consumption levels increase despite a fixed supply of renewable fresh water. Meeting the challenges that water scarcity poses to food production, ecosystem health, and political and social stability will require new approaches to using and managing water. Desalination already plays an essential role in water management. It constitutes a secure source of safe drinking water supply once demand management measures are fully implemented. Overcoming problems related to brine minimization and disposal is key to sustainable, efficient inland water desalination. The main focus of this was the investigation of technical limits and improvements for application in inland desalination. The first part of the dissertation covers the study of Membrane Distillation (MD) for desalination of water. The second part provides a broad perspective of Reverse Osmosis (RO), pretreatments -comparison of slow sand filtration and microfiltration-, post-mortem study of membranes to determining fouling and scaling causes, and RO brine minimization via Vibratory Shear Enhance Processing (VSEP®) for use in RO brine minimization. The study of Vacuum Membrane Distillation in a hollow fiber membrane was studied. Experimental work is supported by an original mathematical model to expose the physics of VMD and support predictions that extend VMD results beyond these generated in the laboratory. The advantages and disadvantages of each pretreatment, including their effects the effect on the performance of RO, a post-mortem membrane study and an economic analysis. The post-mortem study of membranes used during Yuma Desalting Plant operation. This work was used to identify the best pretreatment and more suitable membrane to treat saline water in the lower Colorado River. The work performed during the brine minimization study using VSEP®. This study included experimental data and an extensive economic analysis comparing Ion Exchange (IX) as pretreatment and VSEP® as post-treatment for RO.

We present an alternative method of extracting production related differences from time-lapse seismic data sets. Our method is not based on the actual subtraction of the two data sets, risking the enhancement of noise and introduction of artifacts due to local phase rotation and slightly misaligned events. Rather, it mutes events of the monitor survey with respect to the baseline survey based on the magnitudes of coefficients in a sparse and local atomic decomposition. Our technique is demonstrated to be an effective tool for enhancing the time-lapse signal from surveys which have been cross-equalized

We propose a method for seismic data interpolation based on 1) the reformulation of the problem as a stable signal recovery problem and 2) the fact that seismic data is sparsely represented by curvelets. This method does not require information on the seismic velocities. Most importantly, this formulation potentially leads to an explicit recovery condition. We also propose a large-scale problem solver for the l1-regularization minimization involved in the recovery and successfully illustrate the performance of our algorithm on 2D synthetic and real examples.

Culture-independent DNA sequencing is being used to recover genetic material directly from environmental samples. This has spurred large-scale community efforts to catalogue the diversity of life and its geographic distribution using molecular data. These initiatives stand to revolutionize our understanding of the processes that shape biodiversity and may ultimately provide critical information for setting public health, environmental, and economic policies. To achieve these aims new tools are required to effectively explore these large biogeographic datasets. This thesis introduces a novel technique for visualizing hierarchically organized data in a geographic context that illustrates the influence of a geographic or environmental gradient on the phylogenetic relationships between organisms or the similarity of biological communities. This technique is incorporated into GenGIS, open-source software that supports the integration of digital map data with genetic sequences and environmental information from multiple sample sites. GenGIS addresses the need for an interactive geospatial analysis environment capable of handling large biogeographic datasets where a wealth of sequence data is available for each sample site. This is accomplished through a rich set of analysis options that produce georeferenced visualizations for data exploration and hypothesis generation. Studies conducted by myself and other research groups have used GenGIS to investigate the diversity of viruses, bacteria, plants, animals, and even language families. I then explore measures of beta diversity that aim to assess the influence of geographic or environmental gradients on the similarity of biological communities. This thesis examines phylogenetic beta-diversity measures that determine community variation by considering the relationships between organisms in a phylogenetic tree. A large comparative study is performed in order to assess specific properties and performance characteristics of these measures. Many measures of phylogenetic beta diversity were found to be robust to sequence clustering, the addition of an outlying basal lineage, root placement, and the presence of rare organisms. Additionally, performance was found to differ substantially under different models of community variation. This thesis then describes how an important class of phylogenetic beta-diversity measures can be calculated over phylogenetic networks in order to account for uncertainty and conflict in inferred ancestral relationships.

This thesis has improved Baltazar's methodology for potential energy savings estimation from retro-commissioning/retrofits measures. Important improvements and discussions are made on optimization parameters, limits on optimization parameter values, minimum airflow setting for VAV systems, space load calculation, simulation of buildings with more than one type of system, AHU shutdown simulation, and air-side simulation models. A prototype computer tool called the Potential Energy Savings Estimation (PESE) Toolkit is developed to implement the improved methodology and used for testing. The implemented methodology is tested in two retro-commissioned on-campus buildings with hourly measured consumption data. In the Sanders Corps of Cadets Center, the optimized profiles of parameter settings in single parameter optimizations can be explained with engineering principles. It reveals that the improved methodology is implemented correctly in the tool. The case study on the Coke Building shows that the improved methodology can be used in buildings with more than one system type. The methodology is then used to estimate annual potential energy cost savings for 14 office buildings in Austin, TX with very limited information and utility bills. The methodology has predicted an average total potential savings of 36% for SDVAV systems with electric terminal reheat, 22% for SDVAV systems with hot water reheat, and 25% for DDVAV systems. The estimations are compared with savings predicted in the Continuous Commissioning assessment report. The results show it may be helpful to study the correlation by using generalized factors of assessment predicted energy cost savings to estimated potential energy cost savings. The factors identified in this application are 0.68, 0.66, and 0.61 for each type of system. It is noted that one should be cautious in quoting these factors in future projects. In the future, it would be valuable to study the correlation between measured savings and estimated potential savings in a large number of buildings with retrocommissioning measures implemented. Additionally, further testing and modifications on the PESE Toolkit are necessary to make it a reliable software tool.

Background: Dementia leads to progressive cognitive and functional decline. Population aging is a concern, and the healthcare system must refocus its limited resources to keep up with service demands. Three cholinesterase inhibitors (ChEIs) – donepezil, galantamine and rivastigmine – have been approved for the treatment of dementia and are covered under Ontario’s formulary plan, but there has been little research regarding their economic impact. Methods: The purpose of this study was to describe the patterns of use of ChEIs, and to assess associated health resource utilization and costs to Ontario’s healthcare system. Anonymized patient-level data from seven provincial administrative databases were linked at the Institute for Clinical and Evaluative Sciences at Queen’s University. First-time users of ChEIs aged 66 years and older were identified between April 1st, 2004 and March 31st, 2009, and were followed until treatment discontinuation or up to one year following their index date. Health resource use was classified into six care categories: prescription drugs, physicians, long-term care, home care nursing, emergency department, and hospitalizations. Chi-square, Kruskal-Wallis ANOVA and linear regression were employed to compare resource use between users of the three ChEIs. Results: In the cohort (N=40,057), the majority were prescribed donepezil (n=24,347), were female (60.5%) and had at least one other co-morbid disease. The odds of discontinuation were 1.47 (1.36, 1.60) and 1.26 (1.17, 136), higher for rivastigmine users than galantamine and donepezil users, respectively. Between 2005 and 2008, overall healthcare costs increased from $95.2 million to $106.1 million. Prescription drugs comprised 33% of all healthcare costs. ChEIs accounted for half of all prescription drug costs. Overall mean annual healthcare system cost per patient was $12,679.47 ($12,510.86, $12,848.08). Predictors of overall healthcare costs included long-term care, co-morbidity status, hospitalization and hip fractures. Conclusions: Prescription drugs account for a substantial proportion of healthcare costs for patients with dementia, and the amount attributable to ChEIs alone is significant. Knowing the health service utilization patterns for dementia patients can help healthcare professionals and decision-makers plan patient care and timely resource allocation. The results stress the utility of administrative databases and the need for further research for this disease. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2011-11-01 15:49:58.417

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Through the National Environmental Management Act (No. 107 of 1998), the South African Department of Environmental Affairs and Tourism (DEAT) introduced the concept of the Waste Hierarchy (Reduce - Reuse - Recover - Dispose) as the only possible road towards sustainable development. This concept of sustainable waste management was extended into the Polokwane Declaration on Waste Management which identified Zero Waste as the ultimate goal for sustainable waste management systems in South Africa. Zero Waste is defined as the concept of using all waste produced in a certain area for production activities in that area when it is environmentally acceptable, socially equitable and economically viable, with unavoidable residual waste going to landfill. The aim of this thesis is to test the applicability of Zero Waste to post-consumer waste arising from rural and urban areas. The primary reason that this study has been attempted is that little research in South Africa has focused on the demand-side management of post-consumer waste, and that whatever research that has been undertaken has focused almost exclusively on waste management in urban areas. In order to realise the aim of this thesis, two case studies were selected and analysed: one rural and one urban. These case studies were selected due to differences in characteristics of the waste arising from households, existing waste management systems and socio-economic indicators for households in these areas. In each case study, a proposed Zero Waste Scheme was assessed for application based on four sustainability criteria: environmental, social, economical and institutional. The Zero Waste Schemes are based on the conceptual Zero Waste Model (ZWM) that has been specifically developed as the main tool for conducting this research. The development and use of the ZWM in assessing waste management systems in South Africa is a significant contribution of this thesis to knowledge. Generally, the results showed that the proposed Zero Waste Schemes could meet three of the evaluation criteria used in the investigation, but could not meet the fourth: institutional sustainability. For this reason, the Zero Waste Schemes could not be implemented since the municipalities responsible for waste management in those areas did not have the capacity administrative, financial resources and political will - to implement them. Thus, institutional sustainability has been shown to be the main constraint in the application of Zero Waste Schemes in post-consumer waste management systems in South Africa. This is another significant contribution of this thesis to knowledge.Other significant findings from this study reveal that rural areas lack basic waste collection and disposal systems; hence this lack in service delivery prevents full implementation of Zero Waste Schemes in these areas. In contrast, households in urban areas are served by integrated waste management systems that extend to most households, and most of these households are able to finance the waste management services provided. The existence of the integrated waste management systems was used as a basis for introducing waste minimisation and at-source separation of recyclables in order to reduce the amount of waste needing disposal. Education of households in urban areas has been identified as a key factor in establishing Zero Waste Schemes in the case study areas. In conclusion, it has been shown in this thesis that although Zero Waste Schemes are theoretically applicable to rural and urban areas of South Africa, institutional constraints that will have to be overcome in order to make Zero Waste a reality. Implicit in this conclusion is the extension of waste collection services to rural households and the full participation of rural and urban households in Zero Waste Schemes, participation which can only be verified by actual implementation of the schemes. This is the next step in the approach towards Zero Waste within post-consumer waste management in South Africa. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2009.

The effectiveness of partial ozonation of return activated sludge for enhancing denitrification and waste sludge minimization were examined. A pair of nitrifying sequencing batch reactors was operated in either aerobic or alternating anoxic/aerobic conditions, with one control and one ozonated reactor in each set. The amount of solids decreased with the ozone dose. Biomass in the anoxic/aerobic reactor was easier to destroy than in the aerobic one, generating approximately twice as much soluble chemical oxygen demand (COD) by cell lysis. Increased COD favoured production of extracellular polymers in ozonated reactors, enhancing flocculation and improving settling. Floc stability was also strengthened in prolonged operation in alternating treatment, resulting in declined solids destruction. Dewaterability was better in alternating reactors than in aerobic ones indicating that incorporation of an anoxic zone for biological nutrient removal leads to improvement in sludge dewatering. The negative impact of ozonation on dewaterability was minimal in terms of the long-term operation. Ozone successively destroyed indicator estrogenic compounds, contributing to total estrogen removal from wastewater. Denitrification rate improved up to 60% due to additional carbon released by ozonation. Nitrification rates deteriorated much more in the aerobic than in the alternating reactor, possibly as a result of competition created by growth of heterotrophs receiving the additional COD. Overall, ozonation provided the expected benefits and had less negative impacts on processes in the alternating treatment, although after prolonged operation, benefits could become less significant. The alternating anoxic/aerobic reactor achieved twice the nitrification rates of its aerobic counterpart. Higher removal rates of estrogens were associated with higher nitrification rates, supporting the contention that the nitrifying biomass was responsible for their removal. The alternating treatment offered the better estrogen biodegradation. Microbial populations in both reactors were examined with fluorescent in situ hybridization. Dominance of rapid nitrifiers like Nitrosomonas and Nitrobacter (79.5%) in the alternating reactor, compared to a dominance of slower nitrifiers like Nitrosospira and Nitrospira (78.2%) in the aerobic reactor were found. The findings are important to design engineers, as reactors are typically designed based on nitrifiers’ growth rate determined in strictly aerobic conditions.