No description available.

The Upper Cretaceous Alderson Member is a prolific gas (biogenic) producer in western Canada. In the Hatton Gas Pool area (southwest Saskatchewan), Alderson Member strata from ten drill-cores have been examined and classified based on sedimentological and ichnological character. Core analysis has determined that Alderson Member deposits comprise thick intervals of pervasively bioturbated strata. Using spot-minipermeametry and high-pressure mercury injection porosimetry methods, the influence of pervasively bioturbated intervals on the overall resource potential of Alderson Member strata is evaluated. Results from permeability and porosity testing demonstrate that pervasively bioturbated rock fabrics appear to locally enhance the overall storage and vertical transmission of gas from Alderson Member reservoirs.

Drug transport across the intestinal epithelium is roughly predicted from permeability values obtained from Caco-2 cell monolayers. This thesis examines the important role of pH and extracellular additives for increasing the reliability and predictivity of the in vitro screening system, Caco-2. It was shown that the passive transport of ionizable compounds may be biased by a false efflux or uptake component, when applying a physiological pH-gradient across the membrane. pH also affected the amount of compound available at the transporter-binding site. Therefore, pH dependence should be considered in studies of such compounds and of drug-drug interactions involving efflux transporters. It was also shown that proton-dependent apical uptake or basolateral efflux should be studied both with and without a pH gradient over the whole monolayers. The two extracellular additives, bovine serum albumin (BSA) and the solubilizing agent, Cremophor® EL, also influenced Caco-2 permeabilities. BSA applied to the receiver side increases, and to the donor side decreases drug permeation according to the drug’s protein binding capacity. Thus, the absorptive transport for both passive and active compounds is favoured, giving a physiologically sound improvement of the Caco-2 cell model. Inclusion of BSA increased both the predictivity and quality of permeability studies, particularly of highly lipophilic, BCS class II compounds. Passive and active transport processes could also be distinguished after accounting for unbound concentrations. The overall effect of Cremophor® EL on the permeability to a drug was compound-specific and probably dependent on micellar incorporation. Cremophor® EL can therefore not be recommended. Neither pH nor BSA affect the functionality of transporters such as P-glycoprotein. However, efflux ratios of ionizable or protein bound drugs are altered in the presence of a pH-gradient or BSA, indicating that an experimental system without protein or pH gradient can over- or underestimate active and passive efflux in drug transport.

Thesis (MScEng)--University of Stellenbosch, 2002 / ENGLISH ABSTRACT: A Representative Unit Cell (RUC) model for flow through two-dimensional porous media is presented and applied to two industrial related problems. The first application is to that of cross-flow in tube banks. Both staggered and square (inline) configurations are investigated and the model results are compared to experimental data. The second application is to flow through a stack in a timber-drying kiln. The RUC model is applied to the anisotropic timber stack ends and the centre part is modelled with a standard duct flow solution. The results of the models applied to a timber stack are compared to experimental data obtained from model tests undertaken in a wind tunnel. The results of the RUC and duct flow models are found to be in excellent agreement with the data of the experimental models. These models may be used to optimize kiln designs. / AFRIKAANSE OPSOMMING: 'n Verteenwoordigende Eenheid Sel (VES) model vir vloei deur twee-dimensionele poreuse media word weergegee en toegepas op twee industriële toepassings. Die eerste toepassing is op dwarsvloei deur banke van buise. Beide gestapelde en inlyn konfigurasies word ondersoek waarvan die model resulte met eksperimentele data vergelyk word. Die tweede toepassing is op vloei deur 'n stapel in 'n hout-droogoond. Die VES model word toegepas op die anisotropiese ente van houtstapels en die middelste seksie word gemodelleer deur 'n standaard kanaalvloei oplossing. Die resultate van die modelle toegepas op n 'houtstapel word vergelyk met eksperimentele data verkry uit model toetse wat in 'n wind-tonnel uitgevoer is. Die VES en kanaalvloei modelle se resultate stem uitstekend ooreen met die data van die eksperimentele modelle. Hierdie modelle kan gebruik word om die ontwerp van droogoonde te optimeer.

With the world’s aging power generation network, especially in Europe and the United States, life-extension of steel plant components is increasingly a critical issue, as components are exposed to high temperatures and pressures during their lifetime, potentially resulting in carbide coarsening, making them prone to creep cavitation, possibly leading to component failure. Therefore, in order to evaluate the likelihood of component failure, non-destructive testing and evaluation procedures must be developed to properly assess the level of degradation in power station steels and ensure that end-of-life conditions are not reached. Electromagnetic (EM) inspection techniques have the potential to assess the level of degradation in power station steels through in-situ measurements. This research work introduces and examines a novel approach in the development of an EM sensor system for long term use. Specifically, it focuses on employing the developed EM sensor system technology in the monitoring of microstructural variations in power generation steels (such as boiler tubes) for in-service monitoring and evaluation during maintenance periods. In this work, controlled measurement of the EM properties (differential permeability) of cylindrical samples, machined from power station pipes (P9) and tubes (T22) in different states of degradation were carried out using two different EM sensor systems. Analytical and numerical methods (Finite Elements) were employed to calculate the sensor response to the samples and EM properties inferred by fitting the models to the measured results. The results from a closed magnetic loop sensor system were also considered, where the magnetic hysteresis curves for the steel samples were measured, from which relative incremental permeability values were obtained. It was found that the incremental permeability values measured by this system were connected to the differential permeability values obtained from the induction spectroscopy. Strong correlations have been drawn between microstructural changes (quantified using Vickers hardness measurements) in heat treated samples and EM properties (incremental and differential permeability). Finally, correlations established using the lab-based closed magnetic loop system are transferred to real-world samples, such as grade 91 open pipe / tube specimens. The measurement results verify that the techniques employed for measuring the EM properties of rod samples produce similar results for the open tube samples, demonstrating the viability of application of EM methods for assessment and monitoring of open power station pipes and tubes in-situ.

La mondialisation des marchés, les changements d’habitudes de consommation et les préoccupations croissantes concernant la sécurité alimentaire et l’environnement sont des éléments moteurs pour le développement des films d’emballage comestibles/biodégradables antimicrobiens. Une utilisation en masse de ce type de film est dépendante principalement des verrous technologiques car le mode de fabrication actuellement utilisé pour ce genre de film consiste à utiliser un procédé (voie solvant) qui n’est pas toujours adapté à une production importante et continue. L’étude présentée ici permet de montrer la possibilité d’obtenir des films comestibles antimicrobiens à partir de caséinate de sodium en utilisant les procédés traditionnels de la plasturgie : extrusion bi-vis et extrusion-gonflage. Grâce aux optimisations des paramètres d’élaboration tels que la température de transformation, le taux de cisaillement et le taux de plastifiant, les matériaux contenant un agent actif naturel : le lysozyme, la nisine ou la natamycine ont gardé en partie leurs activités antimicrobiennes. Par des caractérisations mécaniques et physico-chimiques des films thermoplastiques, il a été démontré que ces films ont des propriétés mécaniques et barrières similaires à ceux fabriqués par voie solvant. Ces propriétés dépendent principalement du taux de plastifiant. Ainsi, il est possible de fabriquer des films comestibles antimicrobiens de caséinate de sodium avec de bonnes propriétés mécaniques et barrières qui ne sont pas affectées par la transformation thermomécanique et qui peuvent être adaptées en fonctions des applications en variant le taux de plastifiant / Because food market becomes international, consumers are changing their habits and they are more concerned about food security and environmental issues, there are driving forces for the development of edible/biodegradable antimicrobial packaging films. However, fabrication process (solution-casting) of these kinds of films isn’t always suitable for a continuous industrial big production. The present study demonstrates the suitability of sodium caseinate based edible antimicrobial films to be fabricated by some conventional plastic transformation processes: twinscrew extrusion and blown-film extrusion. Thanks to the optimizations of elaboration parameters such as extrusion temperature, shear and plasticizer ratio, the materials incorporated with one of the following active agents: lysozyme, nisin or natamycin, partially kept their antimicrobial activity. Physical-chemical film characterization of films emphasized that the type of transformation process doesn’t have any influence on tensile or gas barrier properties. These properties are mainly affected by plasticizer type and content. Thus, sodium caseinate based edible antimicrobial films can be produced successfully by thermo-mechanical processes without losing good mechanical and gas barrier properties

No description available.

[pt] Esta pesquisa teve como principal objetivo contribuir para a avaliação da influência da forma dos grãos na condutividade hidráulica (k) de areias. Para tanto, ensaios de laboratório foram realizados em uma amostra da areia da Praia de Ipanema (D10 = 0,28 mm, D30 = 0,34 mm, D50 = 0,41 mm, D60 = 0,45 mm, CNU = 1,61 e CC = 0,92), constituída por grãos subarredondados a arredondados (esfericidade = 0,65 e arredondamento = 0,70), e em uma amostra de microesferas de vidro, tipo Drop-On II A (esfericidade = 0,95 e arredondamento = 0,95), preparada com granulometria igual à da areia. O programa experimental envolveu: (a) limpeza e tratamento das amostras; (b) análises microscópicas para avaliação da forma dos grãos; (c) ensaios de granulometria por peneiramento; (d) reconstituição granulométrica da amostra de microesferas de vidro; (e) densidade relativa (Gs) das microesferas de vidro; (f) ensaios de índices de vazios máximo, pelo método B da ABNT (2020), e ensaios de índices de vazios mínimo e intermediários, pela método MSP de Miura e Toki (1982); e (g) ensaios de permeabilidade sob carga hidráulica constante em permeâmetro de parede rígida e em permeâmetro de parede flexível. Para ambas as amostras, verificou-se experimentalmente a validade da relação linear entre a condutividade hidráulica (k) e e(3)/(1+e), sendo e o índice de vazios, em consonância com as formulações teóricas propostas por Kozeny-Carman (1927) e por Taylor (1948). Para um dado índice de vazios, constatou-se que a condutividade hidráulica da amostra de microesferas de vidro é maior do que a da amostra da areia da Praia de Ipanema. / [en] The main objective of this research was to contribute to the evaluation of the influence of the grain shape on the hydraulic conductivity (k) of sands. For that, laboratory tests were carried out on a sample from Ipanema Beach sand (D10 = 0.28 mm, D30 = 0.34 mm, D50 = 0.41 mm, D60 = 0.45 mm, CNU = 1.61 e CC = 0.92), composed by sub-rounded to rounded grains (sphericity = 0.65 and roundness = 0.70), and on a sample of glass microspheres, Drop-On II A type (sphericity = 0.95 and roundness = 0.95), prepared with the same grain size distribution of the sand. The experimental program comprised: (a) cleaning and processing of the samples; (b) microscopic analysis to evaluate the grain shape; (c) grain-size analysis by sieving; (d) reconstitution of the grain-size distribution of the glass microspheres sample; (e) glass microspheres specific gravity (Gs); (f) maximum void ratio tests, by method B of ABNT (2020), and minimum and intermediate void ratio tests, by MSP method of Miura and Toki (1982); and (g) constant head permeability tests in rigid-wall permeameter and in flexible-wall permeameter. For both samples, it was experimentally verified the validity of the linear relationship between the hydraulic conductivity (k) and e (3)/(1+e), being e the void ratio, in agreement with the theoretical formulations proposed by Kozeny-Carman (1927) and by Taylor (1948). For a given void ratio, it was observed that the hydraulic conductivity of the glass microsphere sample is higher than that of the sample from Ipanema Beach sand.

No description available.

Bovine milk-derived extracellular vesicles (EVs) hold promises as oral drug delivery systems. Since EV bioavailability studies are difficult to compare, key factors regarding EV uptake and intestinal permeability remain little understood. This work aims to critically study uptake and transport properties of milk-derived EVs across the intestinal barrier in vitro by standardization approaches. Therefore, uptake properties were directly compared to liposomes in intestinal Caco-2 cells. Reliable staining results were obtained by the choice of three distinct EV labeling sites, while non-specific dye transfer and excess dye removal were carefully controlled. A novel fluorescence correction factor was implemented to account for different labelling efficiencies. Both EV and liposome uptake occurred mainly energy dependent with the neonatal Fc receptor (FcRn) providing an exclusive active pathway for EVs. Confocal microscopy revealed higher internalization of EVs whereas liposomes rather remained attached to the cell surface. Internalization could be improved when changing the liposomal formulation to resemble the EV lipid composition. In a Caco-2/HT29-MTX co-culture liposomes and EVs showed partial mucus penetration. For transport studies across Caco-2 monolayers we further established a standardized protocol considering the distinct requirements for EVs. Especially insert pore sizes were systematically compared with 3 µm inserts found obligatory. Obtained apparent permeability coefficients (Papp) reflecting the transport rate will allow for better comparison of future bioavailability testing.