Transdermal drug delivery system has been limited to small and lipophilic drugs because skin has the intrinsic function to protect the body preventing entry of the external species into the body. In this thesis, two physical methods were studied to overcome the skin barrier in the controlled breakage of the skin barrier and to deliver macromolecules-based drugs through the skin; (1) polysaccharide dissolving microneedles and (2) micro thermal skin ablation. Polysaccharide dissolving microneedles system was designed to break the skin barrier in a minimized size with the mechanically poor material, to release them into skin with the dissolution of microneedles, and to deliver human growth hormone into the living hairless rats. Micro thermal skin ablation was designed to fabricate the device generating the energy impact with the basis of arc discharge, to transfer the energy impact on the skin, to remove stratum corneum selectively with three-dimensionally controlled manner, and to deliver hydrophilic macromolecules through skin.

Due to escalating energy costs and limited fossil fuel resources, much attention has been given to polymer electrolyte membrane (PEM) fuel cells. Gas diffusion layers (GDLs) play a vital role in a fuel cell such as (1) water removal, (2) cooling, (3) structural backing, (4) electrical conduction and (5) transporting gases towards the active catalyst sites where the reactions take place. The power density of a PEM fuel cell in part is dependent upon how uniform the gases are distributed to the active sites. To this end, research is being conducted to understand the mechanisms that influence gas distribution across the fuel cell. Emerging PEM fuel cell designs have shown that higher power density can be achieved; however this requires significant changes to existing components, particularly the GDL. For instance, some emerging concepts require higher through-plane gas permeability than in-plane gas permeability (i.e., anisotropic resistance) which is contrary to conventional GDLs (e.g., carbon paper and carbon cloth), to obtain a uniform gas distribution across the active sites. This is the foundation on which this thesis is centered. A numerical study is conducted in order to investigate the effect of the gas permeability profile on the expected current density in the catalyst layer. An experimental study is done to characterize the effects of the weave structure on gas permeability in woven GDLs. Numerical simulations are developed using Fluent version 6.3.26 and COMSOL Multiphysics version 3.5 to create an anisotropic resistance profile in the unconventional GDL, while maintaining similar performance to conventional GDL designs. The effects of (1) changing the permeability profile in the in-plane and through-plane direction, (2) changing the thickness of the unconventional GDL and (3) changing the gas stoichiometry on the current density and pressure drop through the unconventional GDL are investigated. It is found that the permeability profile and thickness of the unconventional GDL have a minimal effect on the average current density and current density distribution. As a tradeoff, an unconventional GDL with a lower permeability will exhibit a higher pressure drop. Once the fuel cell has a sufficient amount of oxygen to sustain reactions, the gas stoichiometry has a minimal effect on increases in performance. Woven GDL samples with varying tightness and weave patterns are made on a hand loom, and their in-plane and through-plane permeability are measured using in-house test equipment. The porosity of the samples is measured using mercury intrusion porosimetry. It is found that the in-plane permeability is higher than the through-plane permeability for all weave patterns tested, except for the twill weave with 8 tows/cm in the warp direction and 4 tows/cm in the weft direction, which exhibited a through-plane permeability which was 20% higher than the in-plane permeability. It is also concluded that the permeability of twill woven fabrics is higher than the permeability of plain woven fabrics, and that the percentage of macropores, ranging in size from 50-400 µm, is a driving force in determining the through-plane permeability of a woven GDL. From these studies, it was found that the graduated permeability profile in the unconventional GDL had a minimal effect on gas flow. However, a graduated permeability may have an impact on liquid water transport. In addition, it was found that graduating the catalyst loading, thereby employing a non-uniform catalyst loading has a greater effect on creating a uniform current density than graduating the permeability profile.

<p>This study investigate water uptake in six different species of hardwood in tangential and radial section. Alder (Alnus glutinosa) and beech (Fagus sylvatika) represent semi-diffuse-porous hardwoods. Aspen (Popolus tremula) and birch (Betula pubescens) represent diffuse-porous group; oak (Quercus robur) and ash (Fraxinus excelsior) the ring-porous hardwoods. Spruce (Picea abies) was used as a reference sample.</p><p>Significantly higher water uptake was observed in the diffuse-porous and the semi-diffuse-porous group. Water uptake varied among the species, nevertheless tangential section was more permeable in general. Any impact of density or annual rings width on water uptake was observed. Correlation between ratio of earlywood and latewood and water uptake in dependence on hardwood group was found out. Ring-porous species had low rate of earlywood and low water uptake, whereas diffuse-porous and semi-diffuse-porous hardwoods had high rate of earlywood and high water uptake. Relation between water uptake and microstructure of wood was observed.</p>

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

In landfill design, the containment of solid and liquid contaminant is essential. Leachate is produced from the biodegradation of the waste with the migration of liquid including rain-water through the heap. This liquid can become a health hazard if it leaches into the groundwater. Liners are placed beneath leachate collection systems to prevent leachate from seeping into the soil underneath the landfill. Compacted clay liners, usually containing bentonite clay, are widely used. Bentonite can be characterized by its low hydraulic conductivity and high swell potential. With a low hydraulic conductivity, the liner can serve as a barrier. The high swell potential aids in the integrity of a liner when suffering from cracking or puncturing. The chemicals that can be found in leachate are capable of increasing the clays hydraulic conductivity due to chemical interactions. Chemical compatibility testing - laboratory hydraulic conductivity tests using specific chemical solutions as a permeant - are performed to determine the effects. Laboratory hydraulic conductivity tests, regardless of the permeant, can be time-consuming and expensive. In this study, pure Wyoming bentonite clay and Bentofix clay were used. Deionized water and 0.01M, 0.1M, 0.5M concentrations of four inorganic salt (NaCl, KCl, MgCl2, and CaCl2) solutions were the liquids to which both clays were exposed during testing. Plastic limit and liquid limit tests were run on both clays with all 13 liquids. Laboratory hydraulic conductivity testing with pure Wyoming benonite clay was done with 12 different permeants- all solutions except 0.01M CaCl2 and 0.5M CaCl2. The hydraulic conductivity testing on Bentofix clay was run with 3 permeants- de-ionized water, 0.1M CaCl2, and 0.1M NaCl. The purpose of this study was to determine if a correlation exists between the experimentally determined liquid limit and plastic limit of a specific clay and its hydraulic conductivity when exposed to a synthetic leachate. It was determined that a trend exists that will allow for less expensive and time-consuming determination for hydraulic conductivity of a clay liner when exposed to a specific chemical solution. However, more experimental data need to be collected before a definite trend is verified. The proposed procedure requires that a hydraulic conductivity test of the clay be run using deionized water as the permeant, and plasticity index tests be performed using the leachate.

Single-probe formation testers have been used since the 1950s to measure pore pressure and estimate mobility in fluid-bearing formations penetrated by a well. They are widely used in the oil and gas industry, with tens of measurements often made in every newly drilled well as part of the formation evaluation program. Each measurement consists of placing the tool in the wellbore in direct contact with the face of the formation, extracting a small amount of fluid (from 1 to 50 cc) from the rock and analyzing the fluid pressure response of the system. Pressure interpretation is based on models that assume that temperature within the formation tester flowline remains constant during the tool operation. However, formation pressure measurement involves relatively fast volume and pressure changes within the flowline, which result in temperature changes. These temperature changes are modeled semi-analytically and their effect on pressure transients is analyzed. Temperature variations are accounted for by describing the pressure and temperature dependence of fluid density in the continuity equation, and that temperature varies with both space and time. It is considered here that once a temperature change is imposed on the system, the primary mechanism of thermal transport to achieve equilibrium is conduction. Including temperature in the analysis requires taking into account flowline geometry, and well environmental conditions during the measurement-- namely, wellbore temperature and type of drilling fluid in the wellbore, all of which are immaterial in the isothermal analysis. Arguably, pressure behavior during formation tester measurements could be influenced by several factors. All previous studies related to formation testers assume perfect tool performance and provide explanations to pressure behaviors from the reservoir point of view (e.g., Stewart and Witmmann, 1979; Phelps et al., 1984; Proett and Chin, 1996, etc.). The approach followed here is diametrically opposite. The formation is considered `perfect' from the point of view of pressure measurement, and physical phenomena (thermal transients) that may affect the measured pressure signal are studied. The focus is to understand fundamental aspects of the tool performance that can be studied analytically while minimizing, as much as possible, external parameters that add uncertainty. This dissertation was motivated by inconsistencies observed between the pressure behavior in field measurements and existing (isothermal) theory. For instance, false buildups, buildup overshoots and long time required to reach pressure equilibration, have puzzled those involved in the interpretation of formation tester pressure transients for many years. These behaviors can be reproduced in pressure computations when accounting for temperature variations. The focus of this dissertation is on modeling the tool capability to sense pressure transients associated with recompression of formation fluids several inches away from the wellbore, accounting for temperature variations during the measurement. This is relevant because it is desirable to characterize formation properties beyond the region affected by drilling mud filtrate invasion. In practice, a discrepancy is often observed between formation mobility obtained from drawdown, which depends mostly on formation properties near the wellbore, and mobility obtained from the analysis of late-time buildup pressure, which in theory depends on formation properties farther from the wellbore (Moran and Finklea, 1962). This dissertation examines the influence of late-time tool storage effects caused by thermal equilibration of the flowline fluid on the pressure equilibration and buildup mobility interpretation. It was found that in some cases such late-time storage effects could exhibit a behavior that resembles that expected from spherical flow, that is, the flow regime characteristic of single-probe formation testers; and could therefore invalidate mobility determined by isothermal transient pressure analysis. Formation tester flowline and probe design, test parameters (rate and volume), and environmental conditions during the measurement, mostly type of drilling fluid and wellbore temperature, are important variables in determining the magnitude of late-time storage effects, and hence the tool capability to detect a deep formation signal (spherical flow). Temperature variations affecting late-buildup pressure transients were observed to be more pronounced (listed in order of importance): as wellbore temperature increases; drilling fluid is oil-based mud; flowline with large radius components (e.g. > 1 cm); large flowline volume; small probe radius (< 1 cm); and, large drawdown rate. Temperature effects on the late-buildup also tend to be more significant when mobility is in the 0.1 to 10 md/cp range, that is for those formations more likely, in theory, to exhibit spherical flow regime during buildup. / text

With the growing interest in low-permeability gas plays, foam fracturing fluids are now well established as a viable alternative to traditional fracturing fluids. Present practices in energized fracturing treatments remain nonetheless rudimentary in comparison to other fracturing fluid technologies because of our limited understanding of multi-phase fluid-loss and phase behavior occurring in these complex fluids. This report assesses the fluid-loss benefits introduced by energizing the fracturing fluid. A new laboratory apparatus has been specifically designed and built for measuring the leak-off rates for both gas and liquid phases under dynamic fluid-loss conditions. This report provides experimental leak-off results for linear guar gels and for N2-guar foam-based fracturing fluids under a wide range of fracturing conditions. In particular, the effects of the rock permeability, the foam quality, and the pressure drop are investigated. Analysis of dynamic leak-off data provide an understanding of the complex mechanisms of viscous invasion and filter-cake formation occurring at the pore-scale. This study presents data supporting the superior fluid-loss behavior of foams, which exhibit minor liquid invasion and limited damage. It also shows direct measurements of the ability of the gas component to leak-off into the invaded zone, thereby increasing the gas saturation around the fracture and enhancing the gas productivity during flowback. Our conclusions not only confirm, but add to the findings of McGowen and Vitthal (1996) for linear gels, and the findings of Harris (1985) for nitrogen foams. / text

The 2004 Sumatra-Andaman and the 2011 Tohoku-Oki earthquakes demonstrate the importance of understanding subduction zone earthquakes and the faults that produce them. Faults that produce earthquakes and/or tsunamis in these systems include plate boundary megathrusts, splay faults (out of sequence thrusts), and strike-slip faults from strain partitioning. Offshore Japan, IODP Exp. 314 collected logging while drilling (LWD) data across several seismically-imaged fault splays in the Nankai Trough accretionary prism. I combine LWD resistivity data with a model of fluid invasion to compare the permeabilities of sands. My results indicate that sands within faulted zones are 2-3 orders of magnitude more permeable than similar undisturbed sands. Therefore fault zones are likely to be fluid conduits within the accretionary wedge. Fluids can affect the physical and chemical properties of the faulted material, increasing pore pressures and effectively lubricating the faults. Fluids play an important role in fault slip, but hazard analysis also requires an understanding of fault geometry and slip direction. Both Japan and Sumatra exhibit strain partitioning, where oblique convergence between tectonic plates is partitioned between the megathrust and strike-slip faults proximal to the arc. Offshore Sumatra, I combine profiles from a 2D seismic survey (SUMUT) with previous bathymetry and active seismic surveys to characterize the West Andaman Fault adjacent to the Aceh forearc Basin. Along this fault I interpret transpressional flower structures that cut older thrust faults. These flower structures indicate that the modern West Andaman Fault is a right lateral strike-slip fault and thus helps to accommodate the translational component of strain in this highly oblique subduction zone. Offshore the Kii Peninsula, Japan, I analyze a trench-parallel depression that forms a notch in the seafloor just landward of the megasplay fault system, along the seaward edge of the forearc Kumano Basin. Using a 12 km wide, 3D seismic volume, I observe vertical faults and faults which dip toward the central axis of the depression, forming apparent flower structures. The along-strike geometry of the vertical faults makes predominantly normal or thrust motion unlikely. I conclude, therefore, that this linear depression is the bathymetric expression of a transtensional fault system. While the obliquity of convergence in the Nankai Trough is small (~15 degrees), this Kumano Basin Edge Fault Zone could be due to partitioning of the plate convergent strain. The location of the West Andaman Fault and KBEFZ within the forearc may be controlled by the rheology contrast between active accretionary wedges and the more stable crust beneath forearc basins. / text

Slurry wall is a geotechnical engineering application to control the migration of contaminants by retarding groundwater flow. Sand-bentonite slurry walls are commonly used as levees and containment liners. The performance of bentonite slurry in sand-bentonite slurry walls was investigated by studying the rheological properties of bentonite suspensions, the penetration length of bentonite slurry into clean sand, and stability of the trench under in-situ hydraulic gradients. In this study, the rheological parameters of bentonite suspensions were measured at various bentonite fractions by weight from 6 to 12% with 0-3% of sodium pyrophosphate; an ionic additive to control the rheological properties of the bentonite slurries. The penetrability of the bentonite slurries through Ottawa sand was studied by injecting the slurries into sand columns at different bentonite fractions. The injection tests were performed with the permeameters having different diameters to eliminate any bias on test results due to the different size of permeameter. An empirical correlation for predicting the penetration length of bentonite slurry based on apparent viscosity, yield stress, effective particle size, relative density, and injection pressures was updated by taking into account the effects of the permeameter diameter size. Moreover, the stability of sand-bentonite slurry walls was inspected by studying the hydraulic performance of sand permeated with bentonite suspensions under increasing hydraulic gradients. The critical hydraulic gradient at which washing out of bentonite suspensions is initiated was examined. For specimens with bentonite contents less than the threshold value, the flow occurred through the sand voids and minimal washing out occurred. On the other hand, when the bentonite content was high enough to fill up all the void space between the sand particles, the flow was controlled by the clay void ratio. In this case, washing out did occur with increasing gradients accompanied by an increase in hydraulic conductivity. Accordingly, a relation between the yield stress of bentonite suspensions and the critical hydraulic conductivity was developed. / text