Despite federal, state, and local efforts to combat environmental injustices resulting from heavy industrial activity and high air pollution levels, there is a widespread tendency for hazardous industrial activities to locate near low-income, underrepresented ethnic populations in the United States. The Houston Ship Channel, a port containing the largest concentration of Petrochemical Facilities in the United States, evidences this tendency and provides a stellar example of the nexus between poverty, race, industrial location, and air pollution levels. As a result of the heavy industrial activities in the East Houston area adjacent to the Houston Ship Channel, the surrounding residential area’s air quality levels are significantly poor in relation to federal, state, and local standards. Not coincidentally, these neighborhoods are predominantly low-income and Hispanic in makeup. Unfortunately, there exist few or no federal or state accountability and enforcement mechanisms to resolve this serious problem. In addition, Houston’s lack of zoning and weak land use regulations provides little opportunity for the situation to improve. Although community organization efforts have succeeded in terms of mobilization, education, and consensus building, more effective local planning tools, supported by federal regulations and applied research, would serve to remove the roadblocks that have hindered the advancement of policies promoting enhanced air quality controls, and thus improve the quality of life of the residents of East Houston. / text

This dissertation includes three chapters. The first chapter studies the question of whether countries with different fiscal capacity should optimally have different ex-ante minimum bank capital requirements. In an environment with endogenously incomplete markets and overinvestment because of moral hazard and pecuniary externalities, I show that countries with larger fiscal capacity should have lower minimum ex-ante bank capital requirements. I also show that, in addition to the minimum capital requirement, regulators in countries with a concentrated financial sector and large fiscal capacity (which are also countries with strong moral hazard) should impose a limit on the amount of liquidity pledged by financial institutions in a crisis state (for example, restrict the amount of put options/CDS contracts sold by financial institutions). The second chapter studies the welfare implications of a concentrated, imperfectly competitive banking sector, which faces a bank net worth constraint in a small open economy (SOE) environment. There are two standard sources of inefficiency --- pecuniary externalities, which lead to overinvestment, and a standard monopolistic underinvestment force. I show that the optimal policy instruments include subsidies on firm borrowing costs in certain periods and capital account controls in others, which is a good proxy for the behavior of emerging markets. For every country, there exists a financial sector with a particular banking sector concentration, for which the inefficiencies offset each other and no government intervention is required in some periods. Furthermore, this paper documents a novel theoretical result --- the interaction between future binding bank net worth constraints and dynamic (future) underinvestment could lead to ex-ante overinvestment even in economies with a single monopolistic bank where there are no pecuniary externalities. The last third chapter, which is coauthored with Kenneth Rogoff, evaluates a new class of exchange rate forecasting studies, which claim that structural models are getting closer to being able to forecast exchange rates at short horizons. We argue that misinterpretation of some new out-of-sample tests for nested models, over-reliance on asymptotic test statistics, and failure to sufficiently check robustness to alternative time windows have led many studies to overstate even the relatively thin positive results that have been found. / Economics

Polymer flooding is economically successful in reservoirs where the water flood mobility ratio is high, and/or the reservoir heterogeneity is adverse, because of the improved sweep resulting from the mobility-controlled oil displacement. The performance of a polymer flood can be further improved if the process is dynamically controlled using updated reservoir models and a closed-loop production optimization scheme is implemented. However, the formulation of an optimal production strategy is based on uncertain production forecasts resulting from uncertainty in spatial representation of reservoir heterogeneity, geologic scenarios, inaccurate modeling, scaling, just to cite a few factors. Assessing the uncertainty in reservoir modeling and transferring it to uncertainty in production forecasts is crucial for efficiently controlling the process. This dissertation presents a feedback control framework that (1) assesses uncertainty in reservoir modeling and production forecasts, (2) updates the prior uncertainty in reservoir models by integrating continuously monitored production data, and (3) formulates optimal injection/production rates for the updated reservoir models. This approach focuses on assessing uncertainty in reservoir modeling and production forecasts originated mainly by uncertain geologic scenarios and spatial variations of reservoir properties (heterogeneity). This uncertainty is mapped in a metric space created by comparing multiple reservoir models and measuring differences in effective heterogeneity related to well connectivity and well responses characteristic of polymer flooding. Continuously monitored production data is used to refine the uncertainty map using a Bayesian inversion algorithm. In contrast to classical approach of history matching by model perturbation, a model selection problem is implemented where highly probable reservoir models are selected to represent the posterior uncertainty in production forecasts. The model selection procedure yields the posterior uncertainty associated with the reservoir model. The production optimization problem is solved using the posterior models and a proxy model of polymer flooding to rapidly evaluate the objective function and response surfaces to represent the relationship between well controls and an economic objective function. The value of the feedback control framework is demonstrated with two examples of polymer flooding where the economic performance was maximized. / text

Optimization of the performance of absorption systems during transient operations such as start-up and shut-down is particularly important for small-capacity chillers and heat pumps to minimize lifecycle costs. Dynamic models in the literature have been used to study responses to step changes in a single parameter, but more complex processes such as system start-up have not been studied in detail. A robust system-level model for simulating the transient behavior of an absorption chiller is developed here. Individual heat and mass exchangers are modeled using detailed segmental models. The UA-values and thermal masses of heat exchangers used in the model are representative of a practical operational chiller. Thermal masses of the heat exchangers and energy storage in the heat exchanging fluids are accounted for to achieve realistic transient simulation of the heat transfer processes in the chiller. The pressure drop due to fluid flow across the heat exchangers is considered negligible in comparison to the pressure difference between the high- and low-side components (~ 1.5 MPa). In components with significant mass transfer effects, reduced-order models are employed to decrease computational costs while also maintaining accurate system response. Mass and species storage in the cycle are modeled using storage devices. The storage devices account for expansion and contraction of the refrigerant and solution in the cycle as the system goes through start-up, shut-down, and other transient events. A counterflow falling film desorber model is employed to account for the heat and mass transfer interactions between the liquid and vapor phases, inside the desorber. The liquid film flows down counter to the rising vapor, thereby exchanging heat with the counterflowing heated coupling fluid. A segmented model is used to account for these processes, and a solver is developed for performing rapid iteration and quick estimation of unknown vapor and liquid states at the outlet of each segment of the desorber. Other components such as the rectifier, expansion valves and solution pump are modeled as quasi-steady devices. System start-up is simulated from ambient conditions, and the coupling fluid temperatures are assumed to start up to their steady-state values within the first 90 s of simulation. It is observed that the system attains steady-state in approximately 550 s. The evaporator cooling duty and COP of the chiller during steady-state are observed to be 3.41 kW and 0.60, respectively. Steady-state parameters such as flow rates, heat transfer rates and concentrations are found to match closely with results from simulations using corresponding steady-state models. Several control responses are investigated using this dynamic simulation model. System responses to step changes in the desorber coupling fluid temperature and flow rate, solution pumping rate, and valve setting are used to study the effects of several control strategies on system behavior. Results from this analysis can be used to optimize start-up and steady state performances. The model can also be used for devising and testing control strategies in commercial applications.

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This work is primarily comprised of five self-contained papers. Three papers are applications oriented. A common element in the first three papers is that micro-perforated panels (MPP), the permeable membranes in diesel particulate filters, and a source impedance are all modeled as a transfer impedance. The first paper deals with enhancing the performance of micro-perforated panels by partitioning the backing cavity. Several different backing schemes are considered which enhance the performance without increasing the total volume of the MPP and backing. In the second paper, a finite element modeling approach is used to model diesel particulate filters below and above the plane wave cutoff frequency. The filter itself is modeled using a symmetric finite element model and results are compared to plane wave theory. After the transfer matrix of the filters is known, it is used in three-dimensional finite and boundary element models. The third paper is a tutorial that shows how a source impedance can be modeled using transfer impedance approaches in finite element analysis. The approach used is useful for better understanding the resonance effects caused by pipes upstream and downstream of the exhaust. The fourth paper examines the best practice for the two-load transmission loss measurement. This method was integral to obtaining the measurements for validating the diesel particulate filter models. The fifth paper proposes transmission and insertion loss metrics for multi-inlet mufflers. It is shown that the transmission loss depends on the amplitude and phase relationship between sources (at the inlets) whereas insertion loss depends on both the source strength and impedance for each inlet.

Power converter has played a very important role in modern electric power systems. The control of power converters is necessary to achieve high performance. In this study, a dc-dc buck converter is studied. The parameters of a notional proportional-integral controller are to be selected. Genetic algorithms (GAs), which have been widely used to solve multi-objective optimization problems, is used in order to locate appropriate controller design. The control metrics are specified as phase margin in frequency domain and voltage error in time-domain. GAs presented the optimal tradeoffs between these two objectives. Three candidate control designs are studied in simulation and experimentally. There is some agreement between the experimental results and the simulation results, but there are also some discrepancies due to model error. Overall, the use of multi-domain, multi-objective-optimization-based approach has proven feasible.