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Three sets of concrete blocks were cast to investigate the effects of natural exposure conditions, at the macro and microclimate scale, and field curing on the performance and durability of OPC and OPCjGGBS concretes. These are termed the Loughborough winter series, the Loughborough summer series and the Muscat summer series. Three concrete mixes were investigated in the two Loughborough series (30 and 50 MPa OPC concrete mixes and a 30 MPa OPCjGGBS concrete mix) and two in the Muscat weather series (the two 30 MPa concretes). A group of specimens were cast with each mix consisting of 600 x 500 x 150mm concrete blocks plus control cubes and prisms. The samples were cured in-situ and exposed to a range of curing methods and microclimates. Surface zone properties (up to 50mm depth) were evaluated by air permeability, sorptivity, carbonation, thermogravimetry (TG) and mercury intrusion porosimetry (MIP) tests, conducted after 3 and 12 months of site exposure. The results revealed distinct variations due to macroclimate, microclimate, curing, concrete type and age. The air permeability, sorptivity and carbonation of the concrete exposed under moderate and rainy conditions of a Loughborough summer season were lower than identical concrete cast and cured during a very cold and dry Loughborough winter season. Further, the sorptivity of concrete subjected to the hot and dry climatic conditions of Muscat was significantly higher than companion samples subjected to the temperate Loughborough climate. Significant variations in properties were observed within the two sides of the same concrete element, each subjected to a different microclimate. The air permeability, sorptivity, carbonation and porosity were reduced with increased hessian curing duration. However, premature drying of wet hessian during curing had an adverse effect on concrete quality as this produced concrete of higher permeability and carbonation than non-cured concrete. The application of controlled permeability formwork was effective in improving the concrete's sub-surface properties. The curing affected zone (CAZ) extended to approximately 20mm below the surface of the concrete that was exposed to the Loughborough winter and summer climate, and 40-50mm for the concrete exposed to the Muscat climate, with notable variation in properties due to climate and curing. The TG and MlP results provided insights into the mechanisms associated with the variations in the three concrete's properties due to natural field exposure.

The objective of this thesis was to design a canister for the disposal of spent nuclear fuel and other high-level waste in deep borehole repositories using currently available and proven oil, gas, and geothermal drilling technology. The canister is suitable for disposal of various waste forms, such as fuel assemblies and vitrified waste. The design addresses real and perceived hazards of transporting and placing high-level waste, in the form of spent reactor fuel, into a deep igneous rock environment with particular emphasis on thermal performance. The proposed boreholes are 3 to 5 km deep, in igneous rock such as granite. The rock must be in a geologically stable area from a volcanic and tectonic standpoint, and it should have low permeability, as shown in recent data taken from a Russian deep borehole. Although deep granite should remain dry, water in flooded boreholes is expected to be reducing, but potentially corrosive to steel. However, the granite and plug are the containment barrier, not the canister itself. The canisters use standard oil drilling casings. The inner diameter is 315.32mm in order to accommodate a PWR assembly with a width of 214mm. At five meters tall, each canister holds one PWR assembly. The canister thickness is 12.19mm, with an outer diameter of 339.7mm. A liner can extend to the bottom of the emplacement zone to aid in retrievability. The liner has an outer diameter of 406.4mm and a thickness of 9.52mm. The standard drill bit used with a liner of this size has an outer diameter of 444.5mm. / Contract number: N62271-97-6-0026. / US Navy (USN) author.

The potential of Calcium-Vanadium garnet loaded binary composites for use in the production of planar frequency agile microwave devices has been investigated. A WR90 rectangular waveguide system using the transmission/reflection technique has been used to compare effective medium theory predicted permittivities and permeabilities for unmagnetised and transversely magnetised composites with actual measured composite properties. Use of the the Bruggeman effective medium theory with manufacturer supplied garnet permittivity and values of garnet permeability calculated using simple empirical models were demonstrated to be as accurate as predictions made using the measured properties of the composites' individual constituents. Errors in predicted material properties for unmagnetised and transversely magnetised samples relative to measured data were less than 5% across almost half of the 8.2 -12.4GHz measurement band and within a worst-case error of 15% across the whole band. A series of end-coupled linear microstrip resonators using garnet-loaded composite substrates has been fabricated and tested. Tunabilities in resonance of up to 3.9% at 9.2GHz have been demonstrated for DC magnetic bias fields applied transverse to the microwave magnetic field component. An entirely new and previously unpublished broadband microstrip technique for the measurement of the effective permittivity and permeability of bulk gyromagnetic and gyromagnetic material loaded composite substrates subject to transverse DC magnetic bias fields is presented. This will have wide application in the design of frequency agile microwave integrated circuits.

In many events affecting our civil infrastructure, such as contamination or weathering, it is likely that only the surfaces of the affected building materials will be available for non-destructive measurements. In this work, we describe and analyze surface gas permeability measurements on a variety of natural and engineered building materials using two types of relatively new, non-destructive surface permeameters. It is shown that the surface gas permeability measurements correlate well with each other and could provide rapid estimates of macroscopic gas permeability and degradation of materials due to weathering. It is hypothesized that surface permeability can be used to predict macroscopic wicking of water. The results indicated that macroscopic wicking correlated reasonably well with surface permeability measurements of uniform materials with low permeabilities such as sandstones and clay brick.

La perméabilité vasculaire est une caractéristique cruciale de l’angiogenèse. Les acteurs principaux sont les cellules endothéliales qui la régulent en réponse à divers facteurs perméabilisant, tels que le « Vascular Endothelial Growth Factor » (VEGF). Dans le contexte pathologique du cancer, les cellules tumorales produisent de grandes quantités de VEGF qui stimulent la perméabilité, ce qui leur permet d’infiltrer le réseau vasculaire. Il est connu que la tyrosine kinase Src contrôle cette modulation de la perméabilité. Puisque notre laboratoire a préalablement démontré que la phosphatase de type récepteur (PTP) DEP-1 est impliquée dans l’activation de Src en réponse au VEGF, nous avons émis l'hypothèse que DEP-1 pourrait aussi jouer un rôle dans la perméabilité des cellules endothéliales. Grâce à des expériences de transfections d’ARN interférant, nous démontrons que DEP-1 est important pour la régulation de la phosphorylation de la VE-Cadhérine, un médiateur critique de la perméabilité. L’impact de DEP-1 sur la dissociation de jonctions intercellulaires est également démontré par microscopie à immunofluorescence de cellules endothéliales. DEP-1 est également nécessaire à l’augmentation de la perméabilité induite par VEGF in vitro. Deux résidus tyrosine retrouvés dans la queue carboxy-terminale de DEP-1 sont essentiels à l’activation de Src en réponse au VEGF. Suite à la transfection d’un plasmide encodant DEP-1 muté pour ces deux résidus, nous démontrons aussi leur implication dans la régulation de la perméabilité in vitro par DEP-1. Ces travaux permettent ainsi d’approfondir nos connaissances sur un nouveau régulateur potentiel de la perméabilité vasculaire. / Endothelial cell permeability is a crucial step of angiogenesis. The main actors behind permeability are endothelial cells who accomplish this in response to permeabilizing factors, most notably Vascular Endothelial Growth Factor (VEGF). In a pathological context, migrating tumor cells produce great quantities of VEGF that stimulate an increase of vascular permeability, which allows them to intravasate into the vasculature. Src has been shown to mediate this process. Our laboratory has previously shown that the protein tyrosine phosphatase DEP-1 is involved in the regulation of VEGF-dependant activation of Src. These data thus suggested that DEP-1 might play a role in endothelial cell permeability. Here, we show through siRNA experiments that DEP-1 is important for the regulatory phosphorylation of VE-Cadherin which is critical for the induction of permeability. The impact of DEP-1 on intercellular junction dissociation is also demonstrated through immunofluorescence microscopy of endothelial cells. We further show that DEP-1 is absolutely required for the VEGF-dependent increase of permeability as illustrated by in vitro permeability assay on siRNA-transfected endothelial cells. Finally, we show that tyrosine residues in DEP-1’s carboxy-terminal tail, which are crucial for mediating Src activity in response to VEGF, are implicated in VEGF-dependant increase in permeability by transfecting plasmids coding for DEP-1 mutants of these tyrosine residues. These findings shed light on a novel potential key regulator of in vivo permeability.

The purpose of this study was to construct a flowmeter that could accurately measure the hydraulic permeability of electrospun fibrinogen scaffolds, providing insight into the transport properties of electrospun scaffolds while making the measurement of their topographical features (fiber and pore size) more accurate. Three different concentrations of fibrinogen were used (100, 120, and 150mg/ml) to create scaffolds with three different fiber diameters and pore sizes. The fiber diameters and pore sizes of the electrospun scaffolds were analyzed through scanning electron microscopy and image analysis software. The permeability of each scaffold was measured and used to calculate permeability-based fiber diameters and pore sizes, which were compared to values obtained through image analysis. Permeability measurement revealed scaffold permeability to increase linearly with fibrinogen concentration, much like average fiber diameter and pore size. Comparison between the two measurement methods proved the efficacy of the flowmeter as a way to measure scaffold features.

A subset of cyclophilins have been implicated in mechanisms of neuroinflammation and neurodegeneration that contributes to the pathogenesis of Multiple Sclerosis. Mitochondrial dysfunction leading to mitochondrial permeability transition plays a pivotal role in axonal damage and disease progression in Multiple Sclerosis. Cyclophilin D (CypD) is a crucial regulatory component of the mitochondrial permeability transition pore and it was demonstrated that the cyclophilin D knockout animals showed reduced experimental allergic encephalomyelitis (EAE) clinical disease severity and axonal injury. We investigated the effect of N-methyl-4-isoleucine-cyclosporin (NIM811), a non-immunosuppressive and non-selective cyclophilin inhibitor, on the course and severity of EAE. EAE mice treated with NIM811 showed a significant reduction in clinical disease severity compared to vehicle treated mice. FACS analysis performed with the dissociated thoracolumbar spine showed that NIM811 treatment was associated with a reduction in CNS macrophages but does not alter T-helper lineage frequencies. In addition, we demonstrated NIM811’s effect on crude mitochondrial fraction obtained from brain and liver homogenates of both wild type and CypD knockout mice in order to determine drug specificity. Benefits observed from the pharmacological inhibition of cyclophilin may lead to a novel MS therapy but NIM811’s exact mechanism of action has yet to be elucidated.

La stratégie de Capture et Séquestration du dioxyde de carbone (CO2) (CCS) a pour objectif de récupérer ce gaz en sortie des fumées de combustion des centrales thermoélectriques. La technologie membranaire est une des technologies envisageables. Pour les membranes polymères, de nouvelles voies d'élaboration de matériaux sont entreprises pour la séparation de gaz. Une de ces voies nous a conduits à utiliser le concept de la Chimie Dynamique Constitutionnelle (CDC). Appliqué au domaine des polymères, ce concept conduit aux polymères dynamiques moléculaires covalents (dynamères). Ils sont rendus dynamiques par création de liaisons covalentes réversibles entre unités monomériques moléculaires ou macromoléculaires, ce qui permet de moduler leurs paramètres intrinsèques et leur donnent un caractère adaptif et évolutif. L'objectif de notre étude consiste à élaborer des dynamères susceptibles d'être utilisées comme membrane permsélective par rapport au dioxyde de carbone. Dans un premier temps, le changement climatique ainsi que la technologie de séparation membranaire appliquée aux gaz sont exposés. Par la suite, les mécanismes de transferts de gaz à travers une membrane à base de polymères sont développés. Puis nous avons synthétisé trois séries de dynamères par auto-assemblage de monomères et de macromonomères de géométries et de tailles différentes en créant des liaisons imines. La variation des pourcentages en précurseurs nous permet de moduler la géométrie architecturale du système macromoléculaire. Pour vérifier cela, plusieurs méthodes de caractérisation ont été entreprises. Les analyses spectroscopiques infrarouges et RMN 1H ont permises de mettre en évidence la bonne connexion de nos précurseurs ainsi que le respect des quantités des précurseurs introduites. Les résultats des analyses DSC et de fractions de volumes libres des systèmes macromoléculaires indiquent une évolution dans la géométrie architecturale du système en fonction du pourcentage de précurseurs macromonomériques. Nous avons déterminé le coefficient de perméabilité, de diffusion et de solubilité de gaz pour les membranes dynamères synthétisées par la méthode dit du temps de retard. Au final, pour évaluer les performances de ces membranes dynamères, les résultats de permsélectivité sont reportés sur les diagrammes de Robeson. Ils indiquent que certaines membranes dynamères possèdent des performances en termes de perméabilité et de sélectivité qui sont tout à fait correctes, et ce pour plusieurs couples de gaz et en particulier ceux qui concernent le dioxyde de carbone. / The strategy of Capture and sequestration of carbon dioxide (CO2) (CCS) aims to recover the gases leaving the combustion gases of thermoelectric plants. Membrane technology is one of feasible technologies. For polymeric membranes, new ways of developing materials are undertaken for gas separation. One route led us to use the concept of Dynamic Constitutional Chemistry (DCC) molecular. When applied to polymers, this concept leads to covalent polymer molecular dynamics (dynamères). They are made dynamic by creating reversible covalent bonds between molecular or macromolecular monomer units, which allows modulating their intrinsic parameters and gives them an adaptive and evolutionary nature. The aim of our study was to develop dynamers could be used as membrane for carbone dioxide separation. Firstly, climate change and membrane separation technology applied to gases are exposed. Thereafter, the transfer mechanisms of gases through membrane-based polymers are developed. Then we synthesized three series of dynamers by self-assembly of monomers and macromonomers of geometries and sizes by creating links imines. The percentage change in precursors allows us to modulate the architectural geometry of macromolecular system. To verify this, several methods of characterization were undertaken. Infrared spectroscopic analysis and 1H NMR allowed us to highlight the good connection of our precursors and respect quantities of precursors introduced. The results of DSC analysis and free volume fraction of macromolecular systems show a marked change in the geometry of the system architecture based on the percentage of precursor's macromonomerics. We determined the permeability coefficient, diffusion and solubility of gas for dynamères membranes synthesized by the method of said delay. Finally, to evaluate the performance of these membranes dynamers, permselectivity results are shown in the diagrams of Robeson. They indicate that some membranes have dynamères performance in terms of permeability and selectivity are quite correct, and those for several pairs of gases and in particular those concerning carbon dioxide.