Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 7, 2007). Includes bibliographical references.

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Film flow measurements at several axial positions in round pipes with variousaxial power distributions are presented for conditions corresponding to normaloperation of a BWR. It is confirmed that the film flow rate approaches zero atthe onset of dryout. Selected phenomenological models of annular two-phaseflow are shown to reasonably reproduce the measurements. It is concluded thatmodels are in better agreement with measurements if terms corresponding topossible boiling induced entrainment are excluded. A method to perform film flow analysis in subchannels as a post-processto a standard two-field subchannel code is suggested. It is shown that thisapproach may yield accurate prediction of dryout power in rod bundles to alow computational cost and that the influence of the power distribution is wellpredicted by the model. / QC 20100618

Favorable price trends and increasing demand for renewable energy sources portend accelerating integration of solar photovoltaic (PV) generation into traditional electric power system networks. Managing the variable output of massive PV resources makes system frequency regulation more complex and expensive. ISOs must procure additional regulation and load following capacity, while power plants must supply more regulation work. In contrast to costly physical storage solutions, this thesis proposes to address the issue by reconfiguring the electricity market pricing structure to translate all power imbalances into real-time market price signals. More accurately determining the instantaneous value of energy, electric power markets could reward participants who can quickly respond to frequency fluctuations. By utilizing short term forward markets to monetize the risk associated with intermittency, the true cost of reliability is determined and could reduce wasteful capacity payments. This market redesign is an ideal open platform for disparate smart grid technologies which could encourage all suppliers, loads and generator, to offer supply or reduce consumption when it is needed most and could vastly improve frequency performance metrics.

An optimally designed thermosiphon for power electronics cooling is developed. There exists a need for augmented grid assets to facilitate power routing and decrease line losses. Power converter augmented transformers (PCATs) are critically limited thermally. Conventional active cooling system pumps and fans will not meet the 30 year life and 99.9% reliability required for grid scale implementation. This approach seeks to develop a single-phase closed-loop thermosiphon to remove heat from power electronics at fluxes on the order of 10 - 15 W/cm2. The passive thermosiphon is inherently a coupled thermal-fluid system. A parametric model and multi-physics design optimization code will be constructed to simulate thermosiphon steady state performance. The model will utilize heat transfer and fluid dynamic correlations from literature. A particle swarm optimization technique will be implemented for its performance with discrete domain problems. Several thermosiphons will be constructed, instrumented, and tested to verify the model and reach an optimal design.

Several computer codes based on one and two-group diffusion theory models were developed for SHUFFLE. The programs were developed to calculate power distributions in a two-dimensional quarter core geometry of a pressurized power reactor. The various coarse-mesh numerical computations for the power calculations yield the following: the Borresen's scheme applied to the modified one-group power calculation came up with an improved power distribution, the modified Borresen's method yielded a more accurate power calculations than the Borresen's scheme, the face dependent discontinuity factor method have a better prediction of the power distribution than the node averaged discontinuity factor method, Both the face dependent discontinuity factor method and the modified Borresen's methods for the two-group model have quite attractive features. / Graduation date: 1992

Since its introduction into mainstream society two decades ago, ecotourism has become an international phenomenon. Claimed by its proponents to endorse ecologically, socially, and economically sustainable travel to natural areas, ecotourism is in many ways the conceptual fusion of conservation and development. Yet, despite the optimism often associated with the phenomenon, the question of the degree to which it actually contributes to development, however defined, has become a controversial issue. Theorists and practitioners hold a variety of opinions of ecotourism, ranging from cautious optimism (Honey 2008; Ross & Wall 1999) to outright rejection (Carrier & Macleod 2005; Wheeller 2003). Unfortunately, research shows that the poorest of the poor generally bear the burden of ecotourism initiatives without receiving an equitable share of the associated benefits (Stem et al. 2003; Western & Wright 1994). In response, a sustainable livelihoods approach is proposed as a practical means of understanding the complex livelihood strategies employed by indigenous populations. While tourism research has often focused on the economic impacts of ecotourism initiatives, current livelihoods discourse suggests that the poor draw on a wide range of assets and incorporate a variety of livelihood strategies, in their pursuit of economic gain (Ashley 2002; Ashley et al. 2001; Bebbington 1999; Bennett et al. 1999; Zoomers 1999). This discourse is especially timely for pastoral populations living adjacent to protected areas in Kenya. Recent changes in government policy have promoted the subdivision of land for private ownership (Homewood et al. 2009; Leserogol 2005; Lamprey & Reid 2004), an unexpected transformation that has led to the adoption of ecotourism as a sustainable livelihood strategy. Informed by development theory, tourism theory, and property rights theory, the purpose of this research was to examine the effect of different land tenure regimes on the distribution of benefits accrued from various ecotourism initiatives, and how those benefits impact the livelihoods of the pastoral Maasai living on the periphery of the Maasai Mara National Reserve. Culturally-appropriate, participatory research methods were combined with the Sustainable Livelihoods Framework to document an indigenous perspective on livelihood sustainability. By adapting the conceptual framework to include cultural and historical capital, it served as a lens for viewing and identifying the culturally embedded meaning associated with the recent privatisation of Maasai property. These changes include: significant increases in income generated from ecotourism initiatives, an increased desire to cultivate land, an enhanced capacity for participating in the decision-making process, and greater diversification in local livelihood strategies. However, the empirical evidence also demonstrated that changing property regimes have led to the increased sedentarisation of these semi-nomadic people, resulting in modifications to their pastoral culture, reductions in their herd sizes, and the occasional obstruction of wildlife migratory patterns through the construction of permanent fences.

The performance of a novel micro-thermodielectric power generation device (MTDPG) was investigated in order to determine if thermodielectric power generation can compete with current portable power generation technologies. Thermodielectric power generation is a direct energy conversion technology that converts heat directly into high voltage direct current. It requires dielectric (i.e., capacitive) materials whose charge storing capabilities are a function of temperature. This property is exploited by heating these materials after they are charged; as their temperature increases, their charge storage capability decreases, forcing them to eject a portion of their surface charge to an appropriate electronic storage device. Previously, predicting the performance of a thermodielectric power generator was hindered by a poor understanding of the materials thermodynamic properties and the affect unsteady heat transfer losses have on system performance. In order to improve predictive capabilities in this study, a thermodielectric equation of state was developed that describes the relationship between the applied electric field, the surface charge stored by the thermodielectric material, and its temperature. This state equation was then used to derive expressions for the material's thermodynamic states (internal energy, entropy), which were subsequently used to determine the optimum material properties for power generation. Next, a numerical simulation code was developed to determine the heat transfer capabilities of a micro-scale parallel plate heat recuperator (MPPHR), a device designed specifically to a) provide the unsteady heating and cooling necessary for thermodielectric power generation and b) minimize the unsteady heat transfer losses of the system. The previously derived thermodynamic equations were then incorporated into the numerical simulation code, creating a tool capable of determining the thermodynamic performance of an MTDPG, in terms of the thermal efficiency, percent Carnot efficiency, and energy/power density, when the material properties and the operating regime of the MPPHR were varied. The performance of the MTDPG was optimized for an operating temperature range of 300 500 K. The optimization predicted that the MTDPG could provide a thermal efficiency of 29.7 percent. This corresponds to 74.2 percent of the Carnot efficiency. The power density of this MTDPG depends on the operating frequency and can exceed 1,000,000 W/m3.

Hurricanes have caused severe damage to the electric power system throughout the Gulf coast region of the U.S., and electric power is critical to post-hurricane disaster response as well as to long-term recovery for impacted areas. Managing hurricane risks and properly preparing for post-storm recovery efforts requires rigorous methods for estimating the number and location of power outages, customers without power, and damage to power distribution systems. This dissertation presents a statistical power outage prediction model, a statistical model for predicting the number of customers without power, statistical damage estimation models, and a physical damage estimation model for the gulf coast region of the U.S. The statistical models use negative binomial generalized additive regression models as well as negative binomial generalized linear regression models for estimating the number of power outages, customers without power, damaged poles and damaged transformers in each area of a utility company’s service area. The statistical models developed based on transformed data replace hurricane indicator variables, dummy variables, with physically measurable variables, enabling future predictions to be based on only well-understood characteristics of hurricanes. The physical damage estimation model provides reliable predictions of the number of damaged poles for future hurricanes by integrating fragility curves based on structural reliability analysis with observed data through a Bayesian approach. The models were developed using data about power outages during nine hurricanes in three states served by a large, investor-owned utility company in the Gulf Coast region.

Increased Distributed Generation (DG) presence on radial distribution feeders is becoming a common trend. The existing Overcurrent Protection (OCP) scheme on such feeders consists mainly of overcurrent protection devices (OCPDs) such as fuses and reclosers. When DG is placed on the remote end of a 3-phase lateral, the radial configuration of the feeder is lost. As a result, OCP issues may arise which lead to permanent outages even when the fault is temporary. This thesis presents a new approach that revises the existing OCP scheme of a radial feeder to address the presence of DG. The fuses on the laterals with DGs are removed and multifunction recloser/relays (MFRs) are added to address three specific OCP issues; fuse fatigue, nuisance fuse blowing, and fuse misoperation. The new approach requires no communication medium, provides backup protection for the DG unit, and allows the remaining laterals to retain their existing protective devices. The results are reported using the IEEE 34 node radial test feeder to validate the new approach and the IEEE 123 node radial test feeder to generalize the approach. The new approach completely mitigated the fuse misoperation and nuisance fuse blowing issues and most of the fuse fatigue issues that were present on the radial test feeders. Specifically, the approach demonstrates that coordination between the existing protection devices on radial distribution feeders is maintained in the presence of DG.