Magmas experiencing pressure changes can follow equilibrium or nonequilibrium degassing paths that determine the rate of gas exsolution and the composition of gases exsolved. Many variables influence timescales of equilibration between vapor and melt after a perturbation in pressure, temperature, or other factors, and the magnitude of this equilibration time determines whether the system experiences equilibrium degassing or not. In order to create a simplified framework for assessing degassing regime, we constructed a numerical diffusion model to test the sensitivity of equilibration time to variables such as bubble size, spacing, melt temperature, initial and final system pressures, and water content. We then determined the degassing regime for a range of bubble-spacing and decompression rates as an initial simplified framework to build on. We also attempted the first mixed-volatile continuous decompression experiments in order validate our model and further improve analyses and interpretations of volatile gradients in natural samples.

Icebergs calved from tidewater glaciers represent significant portions of freshwater flux from the Greenland Ice Sheet to the ocean. Using satellite data sets we quantify properties and distributions of icebergs in three fjords with varied properties: Sermilk, Rink Isbræ, and Kangerdlugssûp Sermerssua. Total iceberg volumes in summer in the three fjords average 6.43, 1.69, and 0.19 km^3, respectively, and we calculate cumulative submerged surface areas of iceberg faces to be 213, 55.2, and 7.57 km^2, respectively. We calculate a freshwater flux from iceberg melt of 0.009 – 0.083 m^3 d^-1 in Sermilik Fjord, suggesting a strong potential of iceberg melt water to influence water properties. Properties of icebergs and size distributions are influenced by calving style and grounding line depths of parent glaciers. Variations are represented in the coefficients of generalized Pareto distributions which best describe size distributions in the fjords.

L’amélioration de la solubilité des principes actifs peu solubles est devenue l’un des principaux challenges de l’industrie pharmaceutique. Bien que présentant une structure chimique potentiellement idéale pour interagir avec la cible, elles échouent dans l’efficacité in vivo : après administration, elles ne peuvent se dissoudre dans les milieux aqueux biologiques et par conséquent ne peuvent être transportées sur leur site d’action pour atteindre la concentration efficace, amenant à un échec thérapeutique. De nombreuses stratégies très intéressantes ont été proposées pour surmonter ce sérieux obstacle.Les dispersions solides sont étudiées depuis plus de 40 ans et ont conduit à de très nombreuses publications mais jusqu’à aujourd’hui peu de produits ont été commercialisés principalement pour des raisons de stabilité physico-chimique. Celles-ci ont pour but de présenter le principe actif sous sa forme amorphe : cette dernière présentant un état d’énergie plus élevé et par conséquent une solubilisation facilitée. Dans le même temps, le système doit rester stable durant le stockage, ainsi la recristallisation ou tout autre changement entraînant une modification du profil de libération doivent être évités. Différentes techniques de production peuvent être utilisées pour préparer ce genre de systèmes polymériques tels que l’extrusion en phase chauffante ou l’atomisation-séchage. Le principal objectif de ce travail a été d’améliorer la solubilité des principes actifs peu solubles par formation de dispersions solides utilisant les deux techniques les plus utilisées : l’extrusion en phase chauffante et l’atomisation-séchage. Dans cette étude, le kétoprofène a été incorporé dans des matrices polymériques hydrophiles pour augmenter sa solubilité apparente. Les deux techniques ont été employées et l’Eudragit® E a été considéré comme une matrice intéressante pour plusieurs raisons : c’est un polymère thermoplastique, offrant une stabilité thermique suffisante pour l’extrusion en phase chauffante, il se dissout rapidement en milieu acide et peut interagir avec les groupements acides de par ses nombreux azotes ternaires. Des mélanges binaires « principe actif – Eudragit®E » ainsi que des mélanges ternaires « principe actif – Eudragit®E - PVP », « principe actif – Eudragit®E - PVPVA », « principe actif – Eudragit®E - HPMC » ont été étudiés et caractérisés Les systèmes obtenus ont été caractérisés par macro/microscopie optique, microscopie électronique à balayage, diffraction laser, analyse calorimétrique différentielle modulée, diffraction des rayons X et l’étude du profil de libération in vitro en milieu acide (HCl 0.1M). Les libérations ont été intentionnellement réalisées en condition « non sink » afin d'évaluer le potentiel des formulations à produire des solutions sur-saturées et la durée de ces dernières. Tous les systèmes présentent un profil de libération du kétoprofène beaucoup plus rapide comparé au produit commercial et à la dissolution du principe actif pur. De plus, des solutions sur-saturées peuvent être obtenues et restent stables au moins 2 h. Cependant, en fonction des polymères utilisés, différents profils de libération ont été obtenus indiquant que l’utilisation de matrices polymériques pour l’accélération de la libération de principes actifs peu solubles peut être très complexe puisqu’elle n’est pas seulement influencée par la composition du système mais aussi potentiellement par leur structure interne et notamment par l’homogénéité/hétérogénéité de la distribution des excipients.[...]. / Poor aqueous solubility has become a property of numerous new drug candidates causing major concern. Despite a potentially ideal chemical structure allowing for interaction with the target, these substances fail to be effective in vivo: upon administration, they cannot dissolve sufficiently in the aqueous fluids of the body and, thus, cannot be transported to their site of action to reach therapeutically effective concentrations. Various interesting strategies have been proposed to overcome this crucial hurdle.Solid dispersions have been studied for more than 40 years and lead to numerous interesting research articles. However, today, only a few products have reached the market principally due to problems with the physico-chemical stability. The idea is to transform the crystalline raw material into a physical state having a greater energy in order to increase the driving force for drug dissolution. At the same time, the system should be stable during long term storage, thus, re-crystallization or other system changes, resulting in altered drug release rates, must be avoided. Different manufacturing techniques can be used to prepare such polymeric drug delivery systems, including hot-melt extrusion and spray-drying.The main objective of this work has been to improve drug solubility by forming solid dispersions using the two most employed techniques: hot-melt extrusion and spray-drying. In this study ketoprofen has been incorporated into hydrophilic polymeric matrices to increase its apparent aqueous solubility. Both techniques have been applied and Eudragit® E has been considered to be an interesting matrix former in this case, as it is thermoplastic, provides sufficient thermal stability for hot-melt extrusion, rapidly dissolves at acidic pH and can interact with acidic drugs due to its multiple tertiary ammonium groups. Binary “drug-Eudragit®E” as well as ternary “drug-Eudragit®E-PVP”, “drug-Eudragit®E-PVPVA”, “drug-Eudragit®E-HPMC” combinations were investigated and characterized using X-ray diffraction, mDSC, SEM, optical macro/microscopy, and drug release measurements in 0.1 M HCl before and after storage. Drug release has been intentionally monitored under non-sink conditions, in order to evaluate the potential of the formulations to provide super-saturated solutions and the life-time of the latter. In all cases ketoprofen release was much faster compared to a commercially available product and the dissolution of the drug powder (as received). More important, super-saturated solutions could have been obtained, which were stable for at least 2 h. [...]

Currently, extensive research in using bio‐derived polymers is being done, highlighting the importance of sustainable, green polymeric materials. Some sustainable alternatives to synthetic polymers include lignin, starch, cellulose or blends of these with petroleum‐based polymers. In New Zealand, large quantities of animal derived proteins are available at very low cost, making it ideal as a sustainable alternative to petroleum‐derived polymers. However, the processability of most proteins is very difficult, but can be improved by blending with synthetic polymers, such as polyolefins. To improve, the compatibility between these substances, a functional monomer could be grafted onto the polyolefin chain. Using an appropriate functional group, the polyolefin could then react with certain amino acids residues in the protein. Lysine and cystein are the two most appropriate amino acid residues because of their reactivity and stability at a wide pH range. In this study, free radical grafting of itaconic anhydride (IA) onto polyethylene was investigated. IA was selected because it is capable of reacting with polyethylene and amino acid residues, such as lysine. The objective of the research was to identify and investigate the effect of reaction parameters on grafting. These were: residence time, temperature, initial monomer concentration as well as peroxide concentration and type. Grafting was characterized in terms of the degree of grafting (DOG), percentage reacted and the extent of side reactions. The reaction temperature was taken above the melting point of the polyethylene, monomer and decomposition temperature of the initiator. It was found that above 160 C polymer degradation occurred, evident from sample discolouration. A higher degree of grafting can be achieved by increasing the initial monomer concentration up to a limiting concentration. The highest DOG achieved was about 1.2 mol IA per mol PE, using 2 wt% DCP. When using 2 wt % peroxide, the limiting concentration was found to be 6 wt% IA, above which no improvement in DOG was achieved. It was found that DCP is much more effective at grafting, compared to DTBP because DTBP is more prone to lead to side reactions than DCP. iv It was found that a residence time of 168 seconds resulted in the highest DOG, corresponding to 4 extrusions in series. However, it was also found that an increase in residence time resulted in an increase in polymer degradation. The tensile strength of PE decreased after two extrusions when using DTBP, and three extrusions, when using DCP. Young's modulus decreased only slightly, while all samples showed a dramatic decrease in ductility, even after one extrusion. It was concluded that degradation had a more pronounced effect on mechanical properties than cross‐linking, and residence time should therefore not exceed three extrusions in series, which corresponded to about 126 seconds. It can be concluded that a high reaction temperature and high initiator concentration lead to a low degree of grafting, accompanied by high cross‐linking and increased degradation. On the other hand, high monomer concentration and high residence time lead to a high degree of grafting. Optimising grafting is therefore a trade off between maximal DOG and minimising side reactions such as cross‐linking and degradation and optimal conditions do not necessarily correspond to a maximum DOG. Other factors, such as the use of additives to prevent degradation should also be investigated and may lead to different optimum conditions.

Consumption of plastics has increased exponentially, in line with the world's population. Not surprisingly this is reflected in enormous growth of the plastic industry especially during the last five decades. Commensurate with this, waste produced from plastics consumption has created a major environmental problem. Many types of waste disposal methods have been used all over the world so far, but all of them have disadvantages. Furthermore, some methods are responsible for the generation of green house gases and further contribution to global warming. Recently, reduction of green house gas emission has become a target of most industries. Plastic recycling and reuse breaks the cycle of endless production of virgin polymer and thus contributes to a net reduction of green house gas emission. Recycling of plastics should produce materials with improved properties to replace virgin plastics for a variety of applications. Improvement in the properties of recycled plastics can be achieved by blending with other plastics, by filler addition and by modification using free radical initiators. Introduction of the free radical initiator (organic peroxide) during reprocessing of the recycled plastics has been found to offer significant property improvements to the recycled materials. Extremely small amounts of a free radical initiator (typically ranging between 0.01 wt% to 0.2 wt%) is capable of enhancing the properties of the recycled plastics to a great extent. This project investigates the use of free radical initiators in the recycling of post consumer recycled high density polyethylene using reactive extrusion. Both molecular and rheological characterisation of recycled and reprocessed materials was carried out and this was followed by tensile testing of the modified materials to satisfy end use applications such as packaging and drainage piping. Post consumer recycled high density polyethylene (R-HDPE) resin and virgin high density polyethylene (V-HDPE) were reactively extruded with low concentrations of dicumyl peroxide (DCP) and 1, 3 1, 4 Bis (tert- butylperoxyisopropyl) Benzene (OP2) respectively in a twin screw extruder in order to produce modified materials with varying composition (0.0 wt%, 0.02 wt%, 0.05 wt%, 0.07 wt%, 0.10 wt% and 0.15 wt%) of both organic peroxides. Morphological characterisation using modulated differential scanning calorimetry (MDSC) demonstrated that there is a decrease in the crystallinity level for all the modified samples. Shear rheological tests were carried out to study the structure of the modified materials within the linear viscoelastic region. Viscoelastic parameters, such as storage modulus (G'), loss modulus (G

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Pt, Rh and chromite solubility in basalt-rhyolite mixtures at 1400°C, 0.1 MPa, FMQ +3.4 and FMQ (fayalite-magnetite-quartz-buffer) is presented. Melt samples were equilibrated on Pt90Rh10 loops and in chromite crucibles for up to 100 hours. Pt/Rh solubility decreased 20 and 7-fold respectively, progressing to rhyolitic compositions. Cr solubility decreased 3-fold (FMQ+3.4) and 4-fold (FMQ) over the same compositional interval. At FMQ+3.4, reduced Cr solubility, compared to FMQ, reflects Cr3+ and Fe3+ exchange, stabilizing Fe3+-rich spinel. As SiO2 increases, decreasing Pt/Rh and Cr solubility is interpreted to result from low abundances of non-bridging oxygens and lack of octahedral sites for Cr3+.Numerically simulated diffusive exchange between basalt and rhyolite predicts rapid alloy saturation at high fO2, but undersaturated mixtures at low fO2. Magma mixing produced Fe3+-rich spinel at high fO2; chromite undersaturation occurs near FMQ. Combined chromite and Pt-rich alloy saturation does not appear to result from magma mixing near FMQ.

Pt, Rh and chromite solubility in basalt-rhyolite mixtures at 1400°C, 0.1 MPa, FMQ +3.4 and FMQ (fayalite-magnetite-quartz-buffer) is presented. Melt samples were equilibrated on Pt90Rh10 loops and in chromite crucibles for up to 100 hours. Pt/Rh solubility decreased 20 and 7-fold respectively, progressing to rhyolitic compositions. Cr solubility decreased 3-fold (FMQ+3.4) and 4-fold (FMQ) over the same compositional interval. At FMQ+3.4, reduced Cr solubility, compared to FMQ, reflects Cr3+ and Fe3+ exchange, stabilizing Fe3+-rich spinel. As SiO2 increases, decreasing Pt/Rh and Cr solubility is interpreted to result from low abundances of non-bridging oxygens and lack of octahedral sites for Cr3+.Numerically simulated diffusive exchange between basalt and rhyolite predicts rapid alloy saturation at high fO2, but undersaturated mixtures at low fO2. Magma mixing produced Fe3+-rich spinel at high fO2; chromite undersaturation occurs near FMQ. Combined chromite and Pt-rich alloy saturation does not appear to result from magma mixing near FMQ.