Experimental results on gravity driven fully condensing flows in vertical tubes, their agreement with theory, and their differences with shear driven flows' boundary-condition sensitivities

This doctoral thesis presents the experimental results along with a suitable synthesis with computational/theoretical results towards development of a reliable heat transfer correlation for a specific annular condensation flow regime inside a vertical tube. For fully condensing flows of pure vapor (FC-72) inside a vertical cylindrical tube of 6.6 mm diameter and 0.7 m length, the experimental measurements are shown to yield values of average heat transfer co-efficient, and approximate length of full condensation. The experimental conditions cover: mass flux G over a range of 2.9 kg/m2-s ≤ G ≤ 87.7 kg/m2-s, temperature difference ∆T (saturation temperature at the inlet pressure minus the mean condensing surface temperature) of 5 ºC to 45 ºC, and cases for which the length of full condensation xFC is in the range of 0 < xFC < 0.7 m. The range of flow conditions over which there is good agreement (within 15%) with the theory and its modeling assumptions has been identified. Additionally, the ranges of flow conditions for which there are significant discrepancies (between 15 -30% and greater than 30%) with theory have also been identified. The paper also refers to a brief set of key experimental results with regard to sensitivity of the flow to time-varying or quasi-steady (i.e. steady in the mean) impositions of pressure at both the inlet and the outlet. The experimental results support the updated theoretical/computational results that gravity dominated condensing flows do not allow such elliptic impositions.

Development of a physically-based method for delineation of hydrologically homogeneous regions and flood quantile estimation in ungauged basins via the index flood method

Regional flood frequency techniques are commonly used to estimate flood quantiles when flood data is unavailable or the record length at an individual gauging station is insufficient for reliable analyses. These methods compensate for limited or unavailable data by pooling data from nearby gauged sites. This requires the delineation of hydrologically homogeneous regions in which the flood regime is sufficiently similar to allow the spatial transfer of information. It is generally accepted that hydrologic similarity results from similar physiographic characteristics, and thus these characteristics can be used to delineate regions and classify ungauged sites. However, as currently practiced, the delineation is highly subjective and dependent on the similarity measures and classification techniques employed. A standardized procedure for delineation of hydrologically homogeneous regions is presented herein. Key aspects are a new statistical metric to identify physically discordant sites, and the identification of an appropriate set of physically based measures of extreme hydrological similarity. A combination of multivariate statistical techniques applied to multiple flood statistics and basin characteristics for gauging stations in the Southeastern U.S. revealed that basin slope, elevation, and soil drainage largely determine the extreme hydrological behavior of a watershed. Use of these characteristics as similarity measures in the standardized approach for region delineation yields regions which are more homogeneous and more efficient for quantile estimation at ungauged sites than those delineated using alternative physically-based procedures typically employed in practice. The proposed methods and key physical characteristics are also shown to be efficient for region delineation and quantile development in alternative areas composed of watersheds with statistically different physical composition. In addition, the use of aggregated values of key watershed characteristics was found to be sufficient for the regionalization of flood data; the added time and computational effort required to derive spatially distributed watershed variables does not increase the accuracy of quantile estimators for ungauged sites. This dissertation also presents a methodology by which flood quantile estimates in Haiti can be derived using relationships developed for data rich regions of the U.S. As currently practiced, regional flood frequency techniques can only be applied within the predefined area used for model development. However, results presented herein demonstrate that the regional flood distribution can successfully be extrapolated to areas of similar physical composition located beyond the extent of that used for model development provided differences in precipitation are accounted for and the site in question can be appropriately classified within a delineated region.

Living with Differences: From Everyday Fundamentalisms to Invitational Communication

This project examines fundamentalism understood as an everyday way of living poorly with difference. It demonstrates that the fundamentalist is not reducible to stereotypes of the terrorist, extremist, irrational madman, or religious zealot. All of these characterizations--common in mainstream media--depict the fundamentalist as them, and rarely, if ever, as us. Rather, this project understands fundamentalism in terms of fundamental interpretive constructs that constrain our ways of being-with others, skew our interpretive and responsive possibilities, distort our perceptions of difference, and affirm our poor treatment of others. Following Martin Heidegger's conception of the hermeneutic structure of existence, this dissertation calls attention to the ways in which such fundamentalisms filter our interpretation. Yet the hermeneutic character of existence also highlights the incompleteness of any particular frame of interpretation and indicates the possibility of alternative interpretive responses. The project turns to a feminist theological hermeneutic in order to indicate more hopeful and liberating ways of living with difference, ways that point beyond everyday fundamentalism toward invitational communication. Through new readings of familiar biblical narratives, this dissertation revisits the fundamentalisms that trigger these narratives in order to draw out an alternative feminist theological hermeneutic, or what is termed here an invitational hermeneutic. Each story offers unique ways of making sense of being-with and sharing the world with others of difference that redress the impoverished and fundamentalist forms of self-preserving care and understanding. By examining the well-loved stories of the Good Samaritan, Ruth and Naomi, Queen Esther, and the Apostle Paul and Lydia, the dissertation identifies interpretive and responsive possibilities that together issue an alternative hermeneutical invitation: to understand difference compassionately, to engage strangers and family members alike with rehabilitative care and concernful reticence, and to extend graceful hospitality to others. In these ways, the dissertation indicates possibilities beyond the horizon of fundamentalism, invitational possibilities of living and communicating with difference.