Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The purpose of this investigation was to study the effects of decreasing barometric pressure upon the pressure-flow relationships in a peripheral vascular bed in an attempt at better delineation of the autoregulatory mechanisms. A decrease in barometric pressure does influence the transmural pressure and could theoretically affect smooth muscle tone. An evaluation of the extent of the transmural effect is essential to understanding vascular dynamics at altitudes.

Much of the stochastic groundwater literature is devoted to the analysis of flow and transport in Gaussian or multi-Gaussian log hydraulic conductivity (or transmissivity) fields, Ydx_5ln Kdx_ (x being a position vector), characterized by one or (less frequently) a multiplicity of spatial correlation scales. Yet Y and many other variables and their (spatial or temporal) increments, DY, are known to be generally non-Gaussian. One common manifestation of non-Gaussianity is that whereas frequency distributions of Y often exhibit mild peaks and light tails, those of increments DY are generally symmetric with peaks that grow sharper, and tails that become heavier, as separation scale or lag between pairs of Y values decreases. A statistical model that captures these disparate, scale-dependent distributions of Y and DY in a unified and consistent manner has been recently proposed by us. This new `` generalized sub-Gaussian (GSG)'' model has the form Ydx_5Udx_Gdx_ where Gdx_ is (generally, but not necessarily) a multiscale Gaussian random field and Udx_ is a nonnegative subordinator independent of G. The purpose of this paper is to explore analytically, in an elementary manner, lead-order effects that non-Gaussian heterogeneity described by the GSG model have on the stochastic description of flow and transport. Recognizing that perturbation expansion of hydraulic conductivity K5eY diverges when Y is sub-Gaussian, we render the expansion convergent by truncating Y's domain of definition. We then demonstrate theoretically and illustrate by way of numerical examples that, as the domain of truncation expands, (a) the variance of truncated Y (denoted by Yt) approaches that of Y and (b) the pdf (and thereby moments) of Yt increments approach those of Y increments and, as a consequence, the variogram of Yt approaches that of Y. This in turn guarantees that perturbing Kt5eYt to second order in rYt (the standard deviation of Yt) yields results which approach those we obtain upon perturbing K5eY to second order in rY even as the corresponding series diverges. Our analysis is rendered mathematically tractable by considering mean-uniform steady state flow in an unbounded, twodimensional domain of mildly heterogeneous Y with a single-scale function G having an isotropic exponential covariance. Results consist of expressions for (a) lead-order autocovariance and cross-covariance functions of hydraulic head, velocity, and advective particle displacement and (b) analogues of preasymptotic as well as asymptotic Fickian dispersion coefficients. We compare these theoretically and graphically with corresponding expressions developed in the literature for Gaussian Y. We find the former to differ from the latter by a factor k5hU2 i= hUi 2 (h i denoting ensemble expectation) and the GSG covariance of longitudinal velocity to contain an additional nugget term depending on this same factor. In the limit as Y becomes Gaussian, k reduces to one and the nugget term drops out. Plain Language Summary Much of the stochastic groundwater literature is devoted to the analysis of flow and transport in Gaussian or multi- Gaussian log hydraulic conductivity fields, Y(x), (x being a position vector). Yet Y, as well as many other variables and their increments DY, are known to be generally non- Gaussian. One common manifestation of non- Gaussianity is that whereas frequency distributions of Y often exhibit mild peaks and light tails, those of increments are generally symmetric with peaks that grow sharper, and tails that become heavier, as separation scale or lag between pairs of Y values decreases. A statistical model that captures these disparate, scale- dependent distributions of Y and DY in a unified and consistent manner has been recently proposed by us. This new generalized sub- Gaussian (GSG) model has the form Y(x) 5U(x) G(x) where G(x) is (generally, but not necessarily) a multi- scale Gaussian random field and U(x) is a non- negative subordinator independent of G. The purpose of this paper is to explore analytically lead-order effects that non-Gaussian heterogeneity described by the GSG model have on the stochastic description of flow and transport. Our analysis is rendered mathematically tractable by considering mean uniform steady state flow in an unbounded, two-dimensional domain of mildly heterogeneous Y.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 61-63). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 61-63). Also available on the Internet.

A two-scintillator paddle muon telescope with variable angular acceptance at the earth's surface was used to study correlations between flux distribution and barometric pressure. The detector was placed in 2 different locations around Georgia State University with varying paddle separations of 0, 7, and 14 inches. Correlation and anti-correlation analyses were conducted by using the muon count from the detector along with the barometric pressure, surface temperature, stratospheric temperature and solar activity. It was observed that there was a short and long-term variation relationship between cosmic ray counts and barometric pressure and also cosmic ray counts and temperature. No significant relationship was found between cosmic ray flux and solar activity. A new two-scintillator paddle telescope with larger detecting area was constructed in order to observe a stronger correlation between cosmic ray flux and pressure.

The purpose of this research was to provide a better understanding of meteotsunamis over the eastern Gulf of Mexico along the west coast of Florida and to develop a process for forecasting those events. Meteotsunami waves develop from resonant effects of strong pressure perturbations greater than 1 hPa, moving in excess of 10 m s-1, over water areas up to around 100 m in depth. Meteotsunami events over 0.3 m in height, as measured by three primary NOAA coastal tide gauges at Cedar Key, Clearwater Beach, and Naples, from 2007-2015, impact the Florida Gulf coastline several times per year and are most prevalent south of Cedar Key. Cases that met the indicated thresholds were further examined. A majority of the cases were associated with bands of active convection that brought pressure changes and wind changes. The cases derived from this research provide a baseline for formulating a forecast methodology. The prediction of meteotsunamis is challenging over the marine environment where sub-hourly pressure and wind observations are generally not obtainable. Two forecast methodologies were derived for longer term periods up to several days using numerical model surface pressure data and a refined methodology for forecasts up to several hours in advance of the impacts using a combination of high resolution weather prediction models to provide a robust environment of atmospheric pressure, wind, and pressure fields for prediction of meteotsunamis over shallow shelf waters and available observations. This research illuminates, for National Weather Service forecasters, meteotsunami development and potential hazards related to this phenomenon that can be transmitted to the public within specialized products.

This thesis describes a numerical modelling methodology to interpret dynamic fluctuations in pore-pressures to isolate the effects of loading associated with changes in total soil moisture (site water balance) alone. The methodology is required to enhance the data-interpretation and performance-assessment for potential applications of a novel piezometer-based, large-scale, geological weighing lysimeter. This interpretative methodology is based on a method of superimposing computer-based numerical analyses of independent causes of pore-pressure transients to separate the different pore-pressure responses. Finite element coupled load-deformation and seepage numerical models were used to simulate field-observed piezometric responses to water table fluctuations and loading induced by surface water balance (using meteorological data).<p> Transient pore-pressures in a deep clay-till-aquitard arising from variations in the water table within a surface-aquifer were modelled and removed from the measured pore-pressure record (corrected for earth tide and barometric effects) to isolate and identify pore-pressure fluctuations arising from loading associated with site water balance. These estimates were compared to simulated pore-pressure responses to an independently measured water balance using meteorological instrumentation. The simulations and observations of the pore-pressure responses to surface water balance were in good agreement over the dry years of a 9-year period. Some periods of significant differences did occur during wet years in which runoff, which is not accounted for in the current analyses, may have occurred.<p> The identification of pore-pressure response to total soil moisture loading using the developed numerical modelling methodology enhances the potential for the deployment of the piezometer-based geological weighing lysimeter for different applications which include real-time monitoring of site water balance and hydrological events such as precipitation and flooding. Interestingly, the disparity occurring during the wet years even suggests the potential to adapt the method to monitor runoff (net lateral flow).<p> The methodology also demonstrated the capability to accurately estimate in situ elastic and hydraulic parameters. Calibration of the model yielded equivalent properties of the aquitard (hydraulic conductivity, Kv, of 2.1E-5 m/day and specific storage, Ss, of 1.36E-5 /m) for a Skemptons B-bar coefficient of 0.91 for an assumed porosity of 0.26. Sensitivity tests also provided insight into the consolidation and pressure propagation (swelling) behaviour of the aquitard under parametric variations. The parameters obtained are consistent with range of values reported for glacial clay till soil. Therefore, this work also provides a unique case history of a method for determining, large scale, in situ material properties for geo-engineers and scientists to explore by simply using piezometric and meteorological data.

This thesis describes a numerical modelling methodology to interpret dynamic fluctuations in pore-pressures to isolate the effects of loading associated with changes in total soil moisture (site water balance) alone. The methodology is required to enhance the data-interpretation and performance-assessment for potential applications of a novel piezometer-based, large-scale, geological weighing lysimeter. This interpretative methodology is based on a method of superimposing computer-based numerical analyses of independent causes of pore-pressure transients to separate the different pore-pressure responses. Finite element coupled load-deformation and seepage numerical models were used to simulate field-observed piezometric responses to water table fluctuations and loading induced by surface water balance (using meteorological data).<p> Transient pore-pressures in a deep clay-till-aquitard arising from variations in the water table within a surface-aquifer were modelled and removed from the measured pore-pressure record (corrected for earth tide and barometric effects) to isolate and identify pore-pressure fluctuations arising from loading associated with site water balance. These estimates were compared to simulated pore-pressure responses to an independently measured water balance using meteorological instrumentation. The simulations and observations of the pore-pressure responses to surface water balance were in good agreement over the dry years of a 9-year period. Some periods of significant differences did occur during wet years in which runoff, which is not accounted for in the current analyses, may have occurred.<p> The identification of pore-pressure response to total soil moisture loading using the developed numerical modelling methodology enhances the potential for the deployment of the piezometer-based geological weighing lysimeter for different applications which include real-time monitoring of site water balance and hydrological events such as precipitation and flooding. Interestingly, the disparity occurring during the wet years even suggests the potential to adapt the method to monitor runoff (net lateral flow).<p> The methodology also demonstrated the capability to accurately estimate in situ elastic and hydraulic parameters. Calibration of the model yielded equivalent properties of the aquitard (hydraulic conductivity, Kv, of 2.1E-5 m/day and specific storage, Ss, of 1.36E-5 /m) for a Skemptons B-bar coefficient of 0.91 for an assumed porosity of 0.26. Sensitivity tests also provided insight into the consolidation and pressure propagation (swelling) behaviour of the aquitard under parametric variations. The parameters obtained are consistent with range of values reported for glacial clay till soil. Therefore, this work also provides a unique case history of a method for determining, large scale, in situ material properties for geo-engineers and scientists to explore by simply using piezometric and meteorological data.

Atmospheric monitoring of radionuclides as part of the International Monitoring System requires the capability to differentiate between a radionuclide signature emanating from peaceful nuclear activity and one emanating from a well-contained underground nuclear explosion. While the radionuclide signatures of nuclear weapons are generally well known, radionuclides must first pass through hundreds of meters of earth to reach the surface where they can be detected and analyzed. Less well known is the affect that subsurface vertical transport has on the isotopic signatures of nuclear explosions. In this work, a model is developed, and tested, simulating the detonation of a simple underground nuclear explosion and the subsequent vertical transport of resulting radioxenon to the surface. First, the fast-fission burn of a fissile spherical core surrounded by a layer of geologic media is modeled, normalized to 1 kton total energy. The resulting source term is then used in the testing and evaluation of the constructed vertical transport model, which is based on the double-porosity model of underground fluid transport driven by barometric pumping. First, the ability of the vertical transport code to effectively model the underground pressure response from a varying surface pressure is demonstrated. Next, a 100-day simulation of the vertical migration of a static source is examined, and the resulting cumulative outflow of roughly 1% initial inventory outflow per cycle is found to closely follow the analytical predictions. Finally, calculated radioxenon source terms are utilized to model the resulting vertical transport and subsequent surface outflow. These results are found to be consistent with the physical expectations of the system, and lastly a cursory sensitivity analysis is conducted on several of the physical parameters of the model. The result is that the vertical transport model predicts isotopic fractionation of radioxenon that can potentially lie outside of currently accepted standard bounds. / text