Previous studies have suggested that iron PRBs, receiving high concentrations of inorganic constituents in groundwater, may experience passivation because of the accumulation of inorganic precipitates. In an iron PRB containing more highly reactive material, even though the initial contaminant removal rate is faster than for less reactive material, a faster migration of the contaminant removal front may occur due to the greater reactivity loss, caused by faster accumulation of secondary precipitates. In contrast, an iron PRB containing less reactive material may show a slower accumulation of precipitates, and thus will show a slower migration of the contaminant removal front over time. Thus, it is hypothesized that an iron material having moderate initial reactivity may be more advantageous than material having a higher reactivity in terms of long-term performance. The objective of this study was to test this hypothesis by evaluating the changes of the reactivities of different iron materials in the presence of dissolved CaCO₃. <br /><br /> Four different iron materials (Connelly, G-M, Ispat and Peerless) were selected for the column experiments. The changes in reactivities of the iron and formation of secondary precipitates over time were assessed, primarily by the iron corrosion rates, calculated from the hydrogen gas generation rates, by the cis-DCE removal rates and by the alkalinity profiles. The accumulation of precipitates in the four columns caused passivation of the iron. The passivation of the iron in turn resulted in migration of the mineral precipitation fronts as well as profiles of cis-DCE, TCE, VC, alkalinity, Eh, pH, and chloride. Connelly and G-M had longer periods of operation than Ispat and Peerless and thus their performance was the primary test of the hypothesis. G-M iron, which had the higher initial corrosion rate, compared to Connelly, showed a faster accumulation of precipitates near the influent end. The difference in accumulated precipitates resulted in a difference in the leading edge of the organic profiles and a significant difference in the pattern of passivation, indicating a faster passivation in the region near the influent end for G-M. <br /><br /> Model simulations were performed using the same fitting parameters but with different initial corrosion rate constants to further test the hypothesis. The model provided a reasonable representation of changing reactivities of the columns, being consistent with the observed data. In the simulation for long-term prediction, the cases of higher corrosion rates showed earlier breakthroughs and steeper curves than those of lower corrosion rates. Also, the predictions showed greater porosity loss for the case of higher corrosion rate. Thus, long-term predictions support the hypothesis. Accurate determination of model parameters such as cis-DCE degradation rate constants and iron corrosion rates are required for better predictions of long-term performance.

Past research advocates the need for long-term care (LTC) facilities to adopt a person-centred model of care to optimize residents quality of life. The construct of quality of life in LTC has been defined by satisfaction with a set of domains identified by Kane and colleagues (2003). One goal of this study was to determine which domain is the most predictive of overall well-being among LTC residents in a rural setting. Based on past research and on Deci and Ryans (1985; 1991) self-determination theory, satisfaction with autonomy was predicted to emerge as most predictive of overall well-being. The present study also examined the relation between resident quality of life and well-being, and the degree of routinization (i.e., adherence to a rigid, inflexible daily schedule) within the LTC environment. Routinization is conceptually at odds with a person-centred model of care, yet its relation to the well-being of care recipients had not been examined prior. One hundred and ninety-eight residents from 15 LTC facilities in rural Saskatchewan participated in individual interviews to measure their satisfaction with 11 quality of life domains (Kane et al., 2003), and their overall well-being (using the Memorial University of Newfoundland Scale of Happiness; MUNSH; Kozma & Stones, 1980). One hundred and thirty-one staff from the 15 facilities completed a questionnaire designed to assess routinization within the LTC environment. Contrary to predictions, autonomy failed to emerge as a significant predictor of overall well-being among sample residents. The domain of meaningful activity received residents lowest satisfaction rating of the 11 domains, and also accounted for the most unique variance in overall well-being. Routinization was negatively related to resident quality of life, with staff rating routinization higher in facilities which residents reported lower satisfaction with quality of life. Results provide focus for improving the quality of life of LTC residents, and point to areas for further study.

The polluted agricultural wastewater, after reaching marine recipients, can cause eutrophication. This problem can be tackled and mitigated by using constructed wetlands as water treatment systems. The fact that constructed wetlands work through long periods of time has led many scientists to evaluate how long they can still treat their influents effectively. The development and growth of vegetation and the accumulation of nutrients on the soils in a wetland are expected to occur. These processes change the wetland efficiency to remove pollutants. In this study, a set of wetlands constructed to treat agricultural wastewater were analyzed in different periods to assess if there is a difference in removal efficiency of nitrogen and phosphorus. This assessment was performed by analyzing the retention rate, k and k20 values, which are variables that quantify the nutrients removal, in different periods of each employed wetland. Some of the observations demonstrated differences when comparing different periods of the wetlands. The nitrogen removal presented better performance in one of the employed wetlands when this was older. Another employed wetland has not shown a clear difference between different periods. In the wetlands with high vegetation densities, the nitrogen removal was more stable over consecutive years. The occurrence of oscillations in nitrogen removal was observed more often in the wetlands with the highest vegetation densities over consecutive years. The phosphorus removal presented no clear differences between different periods. The results suggest that the removal of nitrogen improves after wetland creation due to the growth of vegetation. In addition, they suggest that wetlands with high vegetation densities tend to oscillate the nitrogen removal more or less often according to the density of the vegetation due to the balance between denitrification and decomposition. Further, the results suggest that the removal of phosphorus remains unchanged over longer periods than the periods considered in this study (four to six years) due to the deposition of organic matter on the soils.

<p>I characterize optimal long term contracts offered by a monopolist to a buyer whose private valuation evolves according to a branching process with privately known transition probability. The optimal contract can be implemented in a simple way, and presents the buyer with a tradeoff between a high initial fixed fee and low future prices. In an interaction with a long time horizon, the relationship will terminate prematurely with probability close to one. Optimal mechanisms are quite different from models in which the transition probability is known, and the buyer's private information is his initial valuation. Optimal contracts resemble the structure of term life insurance contracts, and have features similar to actual interactions between retailers and suppliers.</p> / Dissertation

ABSTRACT As the population ages and family structure changes quickly, the demand for long-term care services from elderly people increased rapidly. In the aboriginal villages, due to insufficient medical sources, weak economic condition, and lack of young manpower in family, the need of aboriginal elderly people for health care is much more than urban residents. The study field located in Pingtung County is because it is the territory has the most indigenous townships in Taiwan. The study mainly adopts qualitative methodology with small amount of questionnaires to conduct quantitative analysis, it is expected to draw different dynamic result to generate useful outcome. Based on the findings and conclusion after collected and analyzed, the research could provide reference for the development of long-term care project in aboriginal area and long-term caring insurance in future. The research found that the county government and execution organization- NPO both built positive partnership, but the administration of indigenous people and local township office are not involved much. In additional, the provisions of caring health elder in community between Ministry of the interior and Council of indigenous people are duplicated. The users decreased significantly after implementation of users¡¦ pay concept for additional service hours, and it also caused aboriginal women who work as caregiver lost their jobs. In terms of service utilization, the top three services are body clean, house service and mental support, and the result of questionnaires presents great satisfaction. However, considering of weak economic condition, the elderly cannot accept self-afford service yet. Conclusion: 1. Government should adjust different users¡¦ pay level for isle and indigenous township. 2. It should integrate duplicated resources of community-base for health elderly people. 3. Home caregiver can play role of a propagator for welfare and health care policy in village. 4. To develop an integrated long-term care information system to improve the efficiency of case management and service resource.

This dissertation is a narrative inquiry of the ways in which cultural values, norms, and expectations shape the aging experience of elderly adults living independently in Kasson, a small rural town in southeastern Minnesota, and within Prairie Meadows, Kasson's residential assisted living facility. Despite significant evidence of the reciprocal relationship between community connectedness, successful aging, and healthy communities, we know relatively little about the ways in which contextual meanings of old age influence long-term care and perceptions of well-being in late life. I therefore utilized a variety of interpretive methods, including participant observation, textual analysis, in-depth interviews, and photovoice, to complement and enlarge existing research. Ultimately, I engaged crystallization methodology to co-construct with my participants a multivocal, multigenre text of layered accounts, photographs, stories, and personal reflections. My research design and presentation highlight the inherent possibilities of participatory methods, aesthetic ways of knowing, and asset-based community development for influencing policy and practice at individual, community, and societal levels with typically disenfranchised populations in future communication scholarship. My narrative analysis uncovered three overarching narratives - the "small town" narrative, the "aging in place" narrative, and the "old age" narrative - that guide communicative practices within and between Kasson and Prairie Meadows. Overall, elderly adults in these communities negotiate community connectedness in late life by drawing from or re-storying each of the three narratives. First, they co-construct personal and relational identities through social interactions and shared understandings (e.g., civic engagement, church membership, neighborliness, collective history) of what it means to live in a small town. Second, they face uncertainty (e.g., health and dependency issues) by turning to the past to make sense of the present and future. Third, they embrace old age through membership in age-specific contexts (e.g., Red Hats, senior center, Prairie Meadows) while resisting it in others (e.g., tensions between independence, isolation, and communal life). In total, their stories illuminate the ways in which personal meanings and cultural ideologies support and constrain interactions and decisions in late life as individuals strive for long-term living and a meaningful, supportive place in which to grow old.

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The electric power industry is undergoing a restructuring process. The major goals of the change of the industry structure are to motivate competition, reduce costs and improve the service quality for consumers. In the meantime, it is also important for the new structure to maintain system reliability. Power system reliability is comprised of two basic components, adequacy and security. In terms of the time frame, power system reliability can mean short-term reliability or long-term reliability. Short-term reliability is more a security issue while long-term reliability focuses more on the issue of adequacy. This dissertation presents techniques to address some security issues associated with short-term reliability and some adequacy issues related to long-term reliability in deregulated power systems. Short-term reliability is for operational purposes and is mainly concerned with security. Thus the way energy is dispatched and the actions the system operator takes to remedy an insecure system state such as transmission congestion are important to shortterm reliability. Our studies on short-term reliability are therefore focused on these two aspects. We first investigate the formulation of the auction-based dispatch by the law of supply and demand. Then we develop efficient algorithms to solve the auction-based dispatch with different types of bidding functions. Finally we propose a new Optimal Power Flow (OPF) method based on sensitivity factors and the technique of aggregation to manage congestion, which results from the auction-based dispatch. The algorithms and the new OPF method proposed here are much faster and more efficient than the conventional algorithms and methods. With regard to long-term reliability, the major issues are adequacy and its improvement. Our research thus is focused on these two aspects. First, we develop a probabilistic methodology to assess composite power system long-term reliability with both adequacy and security included by using the sequential Monte Carlo simulation method. We then investigate new ways to improve composite power system adequacy in the long-term. Specifically, we propose to use Flexible AC Transmission Systems (FACTS) such as Thyristor Controlled Series Capacitor (TCSC), Static Var Compensator (SVC) and Thyristor Controlled Phase Angle Regulator (TCPAR) to enhance reliability.

Thesis (Ph.D.)--University of Texas at Arlington, 2009.