Anisotropy of hydraulic properties of the subsurface geologic formations is an essential feature that has been established as a consequence of the different geologic processes that undergo during the longer geologic time scale. With respect to subsurface reservoirs, in many cases, anisotropy plays significant role in dictating the direction of flow that becomes no longer dependent only on driving forces like the pressure gradient and gravity but also on the principal directions of anisotropy. Therefore, there has been a great deal of motivation to consider anisotropy into the subsurface flow and transport models. In this dissertation, we present subsurface flow modeling in single and dual continuum anisotropic porous media, which include the single-phase groundwater flow coupled with the solute transport in anisotropic porous media, the two-phase flow with gravity effect in anisotropic porous media, and the natural gas flow in anisotropic shale reservoirs. We have employed the multipoint flux approximation (MPFA) method to handle anisotropy in the flow model. The MPFA method is designed to provide correct discretization of the flow equations for general orientation of the principal directions of the permeability tensor. The implementation of MPFA method is combined with the experimenting pressure field approach, a newly developed technique that enables the solution of the global problem breaks down into the solution of multitude of local problems. The numerical results of the study demonstrate the significant effects of anisotropy of the subsurface formations. For the single-phase groundwater flow coupled with the solute transport modeling in anisotropic porous media, the results shows the strong impact of anisotropy on the pressure field and the migration of the solute concentration. For the two-phase flow modeling with gravity effect in anisotropic porous media, it is observed that the buoyancy-driven flow, which emerges due to the density differences between the phases, migrates upwards and the anisotropy aligns the flow directions closer to the principal direction of anisotropy. Lastly, for the gas flow modeling in anisotropic shale reservoirs, we observe that anisotropy affects the pressure fields and the velocity fields of the matrix and fracture systems as well as the production rate and cumulative production. It is observed from the results that all of the anisotropic cases produce higher amount of gas compared to isotropic case during the same production time. Furthermore, we have also examined the performance of MPFA with respect to mixed finite element (MFE) method over the lowest-order Raviart-Thomas (RT0) space and the first-order Brezzi-Douglas-Marini (BDM1) space. From the comparison of the numerical results we observe that MPFA method show very good agreement with the BDM1 than RT0. In terms of numerical implementation, however, MPFA method is easier than BDM1 and it also offers explicit discrete fluxes that are advantageous. Combining MPFA with the experimenting pressure field approach will certainly adds another advantage of implementing MPFA method as compared with RT0 and BDM1. Moreover, the computational cost (CPU cost) of the three different methods are also discussed.

Membrane traffic in polarised cells was investigated by growing Madin-Darby canine kidney (MOCK) cells on ·permeable polycarbonate filter supports which allowed access to both sides of the cell monolayer. Membrane glycoconjugates on the apical and basolateral cell surfaces were labelled enzymatically with ³H- and ¹⁴C-galactose, respectively, to provide covalent membrane markers. Experiments were done to quantitate membrane traffic during endocytosis at the respective plasma membrane domains and that due to transcytosis. Internalized label was quantitatively distinguished from label on the respective cell surface by its resistance to removal by glycosidases.

Heat stress (HS) is one of the consequential important problems facing the swine industry. The negative effects of HS include reduced growth performance, reproductive efficiency, and carcass quality as well as increased morbidity and mortality. Although, the swine industry has developed several abatement strategies (i.e., fans, cooling pads, sprinklers, etc.), these approaches may be ineffective in the future as global temperatures continue to rise and the frequency of more severe heat waves increases in regions where animal agriculture is prevalent. These extreme heat events put pigs (especially those approaching market weight) at risk for acute hyperthermia that can lead to death unless body temperature is rapidly returned to euthermia and thermoregulatory function is restored.Therefore, evaluating mitigation strategies to promote recovery from acute hyperthermia is of utmost importance for improving pigs’ health and well-being and ensuring profitability and food security. In four experiments, the existence of microclimates in grow-finish barns during late summer was ascertained and a rapid cooling technique using cold water dousing and feed removal to promote recovery from acute hyperthermia in pigs was evaluated. In the first study, it was determined that microclimates exist in grow-finish barns and that pigs raised in pens that were not located directly below air inlets and ventilation fans had greater body temperature and reduced feed efficiency despite similarities in the in-barn ambient temperature and relative humidity. These data exemplifythe importance of adequate ventilation systems in swine barns and the impact of microclimates on pigs’ health and productivity during warm summer months. In the second study, grow-finish pigs that did not have feed access were exposed to acute HS and then rapidly or gradually cooled. Following the acute HS and recovery phase, all pigs were maintained under thermoneutral conditions and then euthanized over three days to determine the temporal effects of the cooling treatment on body temperature and intestinal integrity. The results showed that rapid cooling following acute hyperthermia in pigswas effective in returning body temperature to euthermia more rapidly compared to gradual cooling and rapid cooling prevented further intestinal damage. Based on these results, it was hypothesized that feed removal may have played a role in the effectiveness of rapid cooling. Therefore, a third experiment was conducted in which grow-finish pigs with or without access to feed were exposed to an acute HS challenge and then rapidly cooled. This study concluded that feed access was a determinant factor in the cooling outcome, as the gastrointestinal temperature returned to euthermia during the rapid cooling period more rapidly when feed was removed. Finally, a fourth study was conducted to evaluate the effects of feed removal in the absence of rapid cooling on the systemic inflammatory response and short-term growth performance of grow-finish pigs. However, it was determined that feed removal alone did not reduce the inflammatory response as expected. Overall, these studies demonstrate the risk forgrow-finish pigs during summer heat events and the potential use of rapid cooling in combination with feed removal for promoting recovery from acute hyperthermia in pigs.

Liquid composite molding (LCM) is growing in importance alternative to traditional prepreg-autoclave methods for manufacture aerospace composites. The most significant roadblock to industry's implementation of LCM is the optimization of resin flow to ensure high quality parts. This study developed process optimization tools to foster the adaptation of LCM. The following dissertation characterized the permeability of reinforcement fabrics under various processing conditions, and investigated in-situ bubble flow with carbon fiber. The purpose of this research is to extend the understanding of LCM and push forward the state of the art via sub-studies captured in five chapters, or manuscripts. Research from these manuscripts is as follows. Chapter 3 sets the groundwork for LCM optimization by extending the current theory for assessing 3D permeability of reinforcement fabrics using an ellipsoidal point infusion experiment. The aim was to improve 3D permeability measurement accuracy for LCM processing models. This work is the first to compare solutions in the context of 75 experiments. Chapters 4 and 5 extend permeability analysis to curved and sheared geometries, typical to real-world aerostructures. Chapter 4 demonstrates a method for measurement of curvature effects on permeability with vacuum infusion. A correlation was shown between curvature (as evaluated over four radii) and effective permeability. Chapter 5 researches the shearing of reinforcement fabric (e.g. when reinforcements are draped over double curvature). The study shows that permeability actually increases for mid-range shear angles beyond the shear-locking angle, and develops a technique for obtaining the 3D permeability of sheared fabric.Chapter 6 investigates carbon fiber voids in situ. LCM optimization requires improved void monitoring for carbon fiber. It is challenging to monitor void flow in situ with carbon fiber reinforcements because of fiber opacity. The research builds upon a new automated fluorescent imaging method to monitor void flow in-situ. Results include high-resolution and high-contrast images and 230 data points for infusion velocity vs. void content data.Chapter 7 contributes to the growing interest in LCM processes for aerospace applications by providing a short cost summary of typical processes for manufacturing aerospace composite parts. Data shows that LCM is a financially wise alternative to automated fiber placement (prepreg-autoclave) manufacturing when a void content of 2-2.5% is acceptable. Work on LCM processes optimization indicates that these percentages will reduce in coming years.

Resin transfer molding (RTM) is an infusion-based closed-mold manufacturing process where resin is injected into a preform of dry reinforcement to create a net shape part. Often, when a preform is draped over a mold with complex geometry, such as the double curvature of a dome, a reorientation of the fibers takes place in the form of in-plane shear. This deformation of the reinforcement structure has the potential to adversely affect the resin flow and the filling of the mold during RTM if the manufacturer fails to properly account for the shear effects. Various process simulation tools are being developed and used to simulate infusions in a virtual environment and assist manufacturers in optimizing tooling features and process parameters before needing to invest in tooling or prototypes. Such simulation requires material characterization of the resin viscosity and reinforcement permeability. The latter is a function of the reinforcement architecture and is highly sensitive to perturbations such as shear. Permeability measurement is well represented in the literature, but for ideal fabric arrangements without the deformations caused by complex mold geometries typical to industrial parts. The purpose of this study is to develop the first method for measuring the three-dimensional (3D) permeability tensor of a sheared fiber reinforcement in a single test and empirical models to show the effect shear has on permeability. The method and models are intended to enhance the accuracy of infusion simulation and further advance the development of liquid composite molding processes. Building off the work of previous researchers who have used trellis tools to induce uniform shear on fabric samples and 3D point-infusion tools for radial flow tests, these two methods were combined to measure the sheared permeability of a carbon fiber non-crimp fabric (NCF) in the x, y, and z directions. To mitigate the amount of spring-back that occurs when transferring the sheared preform from the trellis tool to the permeability tool, a method of incorporating an adhesive binder into the preform is presented. Lastly, the permeability data obtained from testing samples sheared at 0, 10, 20, 30, and 40 degrees is documented. Mathematical models are provided based on the data gathered in this work that show the permeability of a NCF in the x, y, and z directions as a function of shear angle. The resulting models indicate an inverse correlation between permeability and shear due to the reorientation of the fibers and closure of preferential flow channels in the preform. These models can be used to predict the permeability for shear angles less than 40 degrees. To validate these results, theoretical shear permeability models are included for comparison. Recommendations for future studies involving the measurement of 3D sheared permeability are discussed.

The permeability of cell membranes varies significantly across both healthy and diseased tissue, and changes in cell membrane permeability can occur during treatment response in tumours. Measurements of cell membrane permeability could therefore be useful for tumour detection and as biomarkers of treatment response in the clinic. As the diffusion of water across the cell membrane is directly dependent on cell membrane permeability, we have investigated the ability of diffusion-diffusion exchange spectroscopy to quantify the diffusion exchange of water in a suspension of yeast, as a first step towards its application in tumours.

The use of iron ore concentrate has become of interest as the demand for higher grade sinter feed is increasing. The fine nature of the concentrate however raises concerns as it can affect permeability during sintering which could have a drastic impact on sinter productivity. In this study the use of iron ore concentrate and micropellets as sinter feed was evaluated. Five mixtures containing different proportions of iron ore concentrate and micropellets, together with iron ore fines, were prepared. These mixtures were agglomerated through pilot scale sinter pot tests, followed by measuring the sinter strength, reduction disintegration and reducibility. Samples of the produced sinters were also subjected to XRF, XRD and SEM-EDS analyses for mineralogical analysis, and MF-XRT for sinter structure analysis. Granulation results revealed that the mixture containing 0% micropellets – 40% concentrate showed superiority in material transfer efficiency while the mixture containing 30% micropellets – 10% concentrate showed superiority in permeability. X-ray diffraction analysis (XRD) revealed an increase in hematite as micropellet content increased. The analysis also revealed high SFCA content for the 0% micropellet – 40% concentrate which decreased as micropellet content increased. This was mainly associated with a decrease in reactivity. Optical microscopy confirmed a large presence of SFCA and also revealed significant precipitation of magnetite and SFCA in the bonding phase structures of the high concentrate containing sinters. It also revealed a pronounced presence of acicular SFCA in the high micropellet containing mixtures. Scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS) revealed a slight consistency in phase chemistry across the different sinter mixtures. This was mainly associated to similar chemical compositions of the starting mixtures. It also revealed that the micropellets maintained a hematite-silica core surrounded by a Fe-rich sintered matrix. It was further determined that the introduction of iron ore concentrate and micropellets did not significantly impact mechanical properties of sinter as similar tumble indices (TI) were observed. A slight variation in reduction disintegration index (RDI) was however seen with high micropellet sinters showing a larger degree of degradation compared to high concentrate containing sinters. Sinter reducibility (RI) also decreased slightly as micropellets increased and this was associated with the inability of micropellets to assimilate during sintering. It was therefore concluded that although micropellets and concentrate can be used as sinter feed, the optimum amount thereof was not yet determined. / Dissertation (MEng)--University of Pretoria, 2020. / Materials Science and Metallurgical Engineering / MEng / Unrestricted

Permeable Interlocking Concrete Pavements (PICP) have seen increased popularity in the principles of Water Sensitive Urban Design and Sustainable Drainage Systems in recent years. To address certain design queries that still existed in industry, a two-year experimental study was conducted. It entailed the construction of an Infiltration Table Apparatus and subjecting a representative volume of PICP to hydraulic testing within it. The study aimed at determining the controls of the flow of water into and through these pavements, the effect of variations in construction materials and incline on them, the validity of the hydraulic testing methods currently being applied to them in industry and lastly, to inform on their infiltration rates. A host of permeability data for PICP was gained and it was found that both the choice of materials and the incline on which PICP are constructed, can change their hydraulic properties drastically. In general, the selection of lower permeability materials in the surface portion of the layer works decreased the overall permeability of the pavement, while increases in inclines did the same. In addition, it was found that field investigation techniques require revision and further innovation before they can be effectively applied to PICP. / Dissertation (MSc)--University of Pretoria, 2019. / Bosun Brick (Pty) Ltd. / Geology / MSc / Unrestricted

>Magister Scientiae - MSc / This study describes porosity and permeability distribution in the deep marine play of the central Bredasdorp Basin, Block 9, offshore South Africa using methods that include thin section petrography, X-ray diffraction, and scanning electron microscopy, in order to characterize their porosity and permeability distributions, cementation and clay types that affect the porosity and permeability distribution. The study includes core samples from nine wells taken from selected depths within the Basin. Seventy three thin sections were described using parameters such as grain size measurement, quantification of porosity and permeability, mineralogy, sorting, grain shape, matrix, cementation, and clay content. Core samples were analyzed using x-ray diffraction for qualitative clay mineralogy and phase analysis. Scanning electron microscope analysis for qualitative assessment of clays and cements. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses were conducted on fifty-four (54) and thirty-five (35) samples respectively to identify and quantify the clay mineralogy of the sandstones. The SEM micrographs are also useful for estimating the type and distribution of porosity and cements. Analyses of these methods is used in describing the reservoir quality. Detrital matrix varies in abundance from one well to another. The matrix consists predominantly of clay minerals with lesser amounts of detrital cements. X-ray diffraction analyses suggest these clays largely consist of illitic and kaolinite, with minor amounts of chlorite and laumontite. Because these clays are highly illitic, the matrix could exhibit significant swelling if exposed to fresh sea water, thus further reducing the reservoir quality. The majority of the samples generally have significant cements; in particular quartz cement occurs abundantly in most samples. The high silica cement is possibly caused by the high number of nucleation sites owing to the relatively high abundance of detrital quartz. Carbonate cement, particularly siderite and calcite, occurs in variable amounts in most samples but generally has little effect on reservoir quality in the majority of samples. Authigenic, pore-filling kaolinite occurs in several samples and is probably related. to feldspar/glauconite alteration, it degrades reservoir quality. The presence of chlorite locally (plate 4.66A & B) and in minute quantities is attributed to a late stage replacement of lithic grains. Don't put references to plates and figures in abstract. A high argillaceous content is directly responsible for the low permeability obtained in the core analysis. Pervasive calcite and silica cementation are the main cause of porosity and permeability destruction. Dissolution of pore filling intergranular clays may result in the formation of micro porosity and interconnected secondary porosity. Based on the combination of information derived from thin section petrography, SEM and XRD, diagenetic stages and event sequences are established for the sandstone in the studied area. Reservoir quality deteriorates with depth, as cementation, grain coating and pore infilling authigenic chlorite, illite and kaolinite becomes more abundant.

This article presents current aspects of transvascular exchange for solutes and water in the microcirculation. Also discussed are various concepts concerning the modulation of the barrier in inflammatory-like states, as well as information describing the receptor-operated channels in endothelial cells and their processing.