During the production of paper in paper mills, detrimental wood resin is released into the water circuit of the mill during the pulping process of the wood into fibres. This wood resin, termed pitch, can detrimentally deposit on the paper and on the paper machine equipment. The deposits mark the paper or can lead to a tear of the paper web involving a loss of output and a reduction in paper quality. Furthermore, the wood resinous compounds in paper mill effluents need to be reduced in order to minimise their toxic effects on water organisms. Talc has been the benchmark for many years as a mineral additive in pitch control. Since the papermaking process has changed over the years, the concept of mineral addition needs to be redefined and adopted towards the new circumstances. By understanding the fundamentals behind the adsorption of wood resin compounds from aqueous systems on to talc new mineral additives can be developed. A model for the determination of the aspect ratio of platy and rod-like particles has been developed, based on commonly available characterisations such as particle size, specific surface area and shape. It was found that the adsorption capacity of a mineral is directly proportional to its specific surface area, but only within its mineral family. Including the effect of surface hydrophilicity and hydrophobicity allowed fine tuning of the adsorption capacity of newly developed calcium carbonate grades. Furthermore, size exclusion effects, in porous, high surface area modified calcium carbonate, were seen to hinder complete coverage of the surface area by wood resin. With increasing pH, the adsorption efficiency of talc for colloidal wood resin was found to decrease. Under these alkaline conditions, which are common in modern paper making processes, talc preferentially adsorbed dissolved species. The use of the newly developed surface treated and modified calcium carbonates allowed more efficient adsorption of the colloidal fraction and, therefore, represent an efficient alternative to talc in pitch control. An increase in temperature led to an increased adsorption capacity of talc. This observation indicates the type of interaction tat controls the adsorption of hydrophobic pitch particles onto talc, i.e. the entropically favoured release of water from the hydrophobic talc surface as well as the hydrophobic methylene backbone of the hemicellulose.

Caribbean coral reefs are in crisis. Degradation of living coral and fish assemblages has accelerated during the past half century, with a suite of anthropogenic drivers –from local fishing pressure to unprecedented global scale climate change– implicated. Accompanying these losses is the physical disintegration of the three-dimensional calcium carbonate reef structure. Flattening of reefs, synonymous with loss of ecosystem function and provision of services, is caused by an imbalance in the carbonate budget: a trade-off between carbonate production and consolidation by calcifying organisms (principally coral-algal symbioses) and framework breakdown by bioeroding organisms and storms. This thesis focuses on expanding our understanding of two functionally critical issues that strongly influence Caribbean coral reef community composition and dynamics, and which look likely to have a key bearing on the future state of reefs in the region: coral photosynthetic endosymbionts, and carbonate budgets. The former exert an important role in the production of the coral carbonate framework, whilst the latter reflect the dynamics of reef carbonate production and erosion. In the first part of the thesis, existing information on rates of carbonate production and erosion on Caribbean reefs is utilised to construct a detailed theoretical carbonate budget model. The model is used to chart historic changes in Caribbean carbonate budgets, tracking reef flattening across time and identifying key ecological drivers of these changes. This “eco-geomorphic” model is then coupled with state-of-the-art climate and ecological models, to project reef processes to the end of the century, asking the question ‘at what point will Caribbean reefs shift to net erosional regimes?’. The models are also used to explore the efficacy of local management and climate mitigation in altering the negative trajectory of reefs under projected warming and ocean acidification. In the second part of the thesis, 632 corals from across the wider Caribbean are screened, to construct the largest recorded baseline of symbiont biogeography for the region’s key remaining reef framework builder, Montastraea annularis. Spatial patterns of symbiont diversity are explored in terms of environmental, geographic and genetic factors, contributing to the growing body of work currently in the early stages of cataloguing symbiont diversity and its ecological significance. Although carbonate budget models forecast a bleak outlook for the Caribbean, detection of widespread low-level prevalence of thermally-tolerant endosymbionts in M. annularis provides a weak ‘nugget of hope’ for potential coral acclimation. Combined local management and aggressive mitigative action on carbon emissions are pre-requisites for maintenance of functioning reefs into the next century. Coral reef conservation efforts can be improved if we fully appreciate the contributions of all reef components –not just the enigmatic ones– to healthy reef functioning.

In today’s drug discovery, the number of candidate drugs based on new molecular entities with poor aqueous solubility is increasing. Since poor aqueous solubility of an active pharmaceutical ingredients (APIs) is associated with low bioavailability and thus limite their therapeutic effect, this is often a great challenge in the development of new drugs when oral administration is the preferred route of administration. A number of different strategies have been developed to circumvent this problem where salt formulations of an API is the most widely employed method. However, new strategies are needed since there is no one solution that solves this issue for all substances. In recent time, the concept of stabilizing poorly soluble APIs in their amorphous form has gained a lot of attention since amorphous compounds exhibit a higher apparent solubility compared to their crystalline counterparts. Amorphous substances are prone to crystallize if left in a non-constricted environment and thus need to be stabilized if the amorphous state is to be conserved until administration. Inorganic mesoporous materials have been proposed as an interesting type of excipients that can conserve the amorphous state of APIs. In this work, the focus was to investigate the possibilities of using a mesoporous type of magnesium carbonate to stabilize the amorphous state of different APIs. Due to the nanometer sized pores in the material, complete conservation of amorphous APIs was obtained. This resulted in both an increase in in vitro release rate and a higher solubility of the substances which may translate to both a faster onset of action and an improved therapeutic effect of the APIs in a clinical situation. The long term stability of formulations was also investigated showing promising results. The results presented in this work show that mesoporous magnesium carbonate represents an interesting type of excipient for oral formulations of APIs with poor aqueous solubility. / <p>Felaktigt ISBN 978-91-554-9702-6 i tryck version.</p>

The applications of calcium-isotope measurements in marine carbonates are explored in several different contexts within this thesis. As a record of global ion fluxes, seawater calcium-isotope ratios can be used as tracers for large weathering imbalances, which develop as a feedback system in response to intervals of climate change. This approach provides valuable constraints on the complex climatic and oceanographic phenomena known as the Oceanic Anoxic Events. Over much longer timescales, the calcium-isotope ratio of seawater is influenced by steady-state processes that reflect the evolution of seawater chemistry. To understand these influences, the modern calcium-isotope budget is assessed quantitatively using a compilation of marine carbonate samples, revealing several distinctive components of the carbonate burial sink that can affect the steady-state balance of the calcium cycle. Changes in the major ion composition of seawater and in the organisms that contribute to sedimentary carbonate burial are shown to contribute significantly to the geological record of seawater calcium-isotope ratios. The importance of skeletal carbonate in the calcium cycle leads to another application of calcium isotopes towards understanding biomineralization. This large and complex topic is approached with calcium-isotope data from two unique growth experiments that constrain some of the mechanisms by which biogenic aragonite acquires its geochemical signatures. This range of topics presents a diverse, but by no means exclusive, sample of the topics that are accessible for investigation through calcium-isotope analysis. The potential of this isotopic tool is demonstrated by the breadth of environments and timescales represented in this work.

Desalination is a technique of producing fresh water from the saline water. Industrial desalination of sea water is becoming an essential part in providing sustainable source of fresh water for a large number of countries around the world. Thermal process being the oldest and most dominating for large scale production of freshwater in today's world. Multi-Stage Flash (MSF) distillation process has been used for many years and is now the largest sector in the desalination industry. In this work, a steady state mathematical model of Multistage Flash (MSF) desalination process is developed and validated against the results reported in the literature using gPROMS software. The model is then used for further investigation. First, a steady state calcium carbonate fouling resistance model has been developed and implemented in the full MSF mathematical model developed above using gPROMS modeling tool. This model takes into consideration the effect of stage temperature on the calcium carbonate fouling resistance in the flashing chambers in the heat recovery section, heat rejection section, and brine heaters of MSF desalination plants. The effect of seasonal variation of seawater temperature and top brine temperature on the calcium carbonate fouling resistance has been studied throughout the flashing stage. In addition, the total annual operating cost of the MSF process is selected to minimise, while optimising the operating parameters such as seawater rejected flow rate, brine recycle flow rate and steam temperature at different seawater temperature and fouling resistance. Secondly, an intermediate storage between the plant and the client is considered to provide additional flexibility in design and operation of the MSF process throughout the day. A simple polynomial based dynamic seawater temperature and different freshwater demand correlations are developed based on actual data. For different number of flash stages, operating parameters such as seawater rejected flow rate and brine recycle flow rate are optimised, while the total annual operating cost of the MSF process is selected to minimise.The results clearly show that the advantage of using the intermediate storage tank adds flexible scheduling in the MSF plant design and operation parameters to meet the variation in freshwater demand with varying seawater temperatures without interrupting or fully shutting down the plant at any time during the day by adjusting the number of stages. Furthermore, the effect of non-condensable gases (NCG) on the steady state mathematical model of MSF process is developed and implemented in the MSF model developed earlier. Then the model is used to study effect of NCG on the overall heat transfer coefficient. The simulation results showed a decrease in the overall heat transfer coefficient values as NCG concentrations increased. The model is then used to study the effect of NCG on the design and operation parameters of MSF process for fixed water demand. For a given plant configuration (fixed design) and at different seawater and steam temperatures, a 0.015 wt. % of NCG results in significantly different plant operations when compared with those obtained without the presence of NCG. Finally, for fixed water demand and in the presence of 0.015 wt. % NCGs, the performance is evaluated for different plant configurations and seawater temperature and compared with those obtained without the presence of NCG.

Lime is one of the largest manufactured chemicals in the United States. The conversion of calcium carbonate into calcium oxide is an endothermic reaction and requires approximately two to four times the theoretical quantity of energy predicted from thermodynamic analysis. With the skyrocketing costs of fossil fuels, how to decrease the energy consumption in the calcination process has become a very important problem in the lime industry. In the present study, many chemicals including lithium carbonate, sodium carbonate, potassium carbonate, lithium chloride, magnesium chloride, and calcium chloride have been proved to be the catalysts to enhance the calcination rate of calcium carbonate. By mixing these chemicals with pure calcium carbonate, these additives can increase the calcination rate of calcium carbonate at constant temperatures; also, they can complete the calcination of calcium carbonate at relatively low temperatures. As a result, the energy required for the calcination of calcium carbonate can be decreased. The present study has aimed at developing a physical model, which is called the extended shell model, to explain the results of the catalytic calcination. In this model, heat transfer and mass transfer are two main factors used to predict the calcination rate of calcium carbonate. By using the extended shell model, not only the catalytic calcination but also the inhibitive calcination of calcium carbonate have been explained.

La partie supérieure de la Formation Khuff est un réservoir représentant le plus grand champ gazier mondial, d'âge Permien supérieur à Trias inférieur. Il est formé de la succession de calcaires, de dolomies et de sulfates. Sa production est principalement contrôlée par des intervalles d'épaisseur généralement inférieure à 10 m, totalement dolomitisés, appelés super-drains ou super-K, connectés sur plusieurs dizaines de kilomètres.Les objectifs de l'étude sont (1) de définir la mise en place et l'extension des super-drains dans un cadre stratigraphique, (2) de comprendre la diagenèse contrôlant leurs propriétés réservoirs et (3) de comparer la mise en place des corps dolomitiques stratiformes précoces ou tardifs liés aux failles à ceux d'un analogue à l'affleurement, à savoir les formations calcaréo-dolomitiques d'âge Jurassique supérieur en Provence.Pour les atteindre, des analyses sédimento-diagénétiques (sédimentologiques, pétrographiques et géochimiques) ont été entreprises sur les deux objets d'études du réservoir de subsurface et de l'analogue réservoir d'affleurement. Pour ce dernier, une modélisation en 3D de corps diagénétiques liés aux failles a été réalisée. Les principaux résultats sont que :- les localisations des super-drains ont été contrôlées par la dynamique sédimentaire de séquences à basse fréquences (SBF) et à haute fréquence (SHF) ;- des super-drains sont localisés au sommet des SBF sous les discontinuités d'émersions et à la limite des fronts de dolomitisation de reflux différé. / The upper part of the Khuff Formation includes the biggest gas reserves in the world, from Upper Permian to Lower Triassic age. It is composed by the succession of limestone, dolomite and sulfate. The gas production is mainly driven by layers typically thinner than 10 m, fully dolomitised, and called super-drains or super-K and connected over several dozen kilometers.The goals of this study are (1) to define the formation and the extension of super-K layers in a stratigraphic framework, (2) to understand the diagenesis controlling their reservoir properties and (3) to compare the creation of early stratabound and late fault-related dolomite bodies with an outcrop analogue, from the limestone and dolomite formations from Provence from Upper Jurassic age.To reach this goal, sedimento-diagenetic analyses (sedimentological, petrographical and geochemical) have been carried out on studied objects, the subsurface reservoir and the outcrop analogue reservoir. For the latter, 3D modelling of fault-related dolomite bodies have been realised. The main results are:- the locations of super-K have been controlled by the sedimentary dynamics of low frequency sequences (SBF) and high frequency sequences (SHF) ;- some super-K are located at the top of SBF under emersion unconformities and at the rim of dolomitisation fronts associated to postponed reflux. The reflux was made of brines, coming from synsedimentary dolomite bodies associated with marine transgressions that followed the emersions. This model is corroborated by an outcrop analogue, which is a dolomite reservoir underlying a long lasting emersion unconformity;

In the region of Bohemian Cretaceous Basin can be found some springs with specific yield over 100 l/s. The doyen of Czech hydrogeology Prof. Hynie described some of those springs to be of karst origin and as the most permeable area he described the so-called transitional facies between shallow-water sandstones and deep-water marlstones. Possibilities of karstification have not yet been studied for rocks in the BCB, so the origin of well-permeable pathways in the BCB is a subject of speculations. This thesis deals with the question of which sedimentary rocks potentially allow the generation of karst permeability in the BCB. To do so, rock samples drilled from outcrops in the BCB were subjected to a fast dissolution simulation by leaching in hydrochloric acid. Carbonate content is measured by a standard and one's own method. Mineral composition, grain size and microscopic structure of rocks are studied with SEM. As is shown, the border of rock karstification is not defined just by the carbonate content, but also the grain size, rock structure and by the occurrence of fine secondary silicate content. Concerning the amount of dissolvable compounds, the border of total disintegration can be at 30 % of carbonate content for some rocks, but the most resistant rocks (mostly fine rocks with SiO2 matrix) stay intact...

Recent studies have investigated the hydrological and geochemical characteristics of karst aquifers in different settings; however, telogenetic karst aquifer processes remain poorly understood. In south-central Kentucky, the iconic Lost River Cave and Valley represents a large, complex telogenetic karst drainage basin with a series of discharge points along a collapsed section of the cave. Two Campbell Scientific® CR1000 automated dataloggers were installed at Blue Hole Four, a primary discharge point of the Lost River Karst Aquifer (LRKA). These dataloggers recorded spring discharge, water temperature, specific conductance (SpC), and pH at ten-minute intervals from January to November, 2013. During the year, data for 34 storm events were captured, including water samples that were analyzed for major cation/anion concentrations. These concentrations were correlated to SpC to yield a continuous record of ionic concentrations. Rainfall data were acquired from the Kentucky Mesonet’s Warren County Site within the LRKA basin. Dissolution rates, Ca2+/Mg2+ ratios, and a mass flux of dissolved CaCO3were calculated to assess aquifer evolution processes and identify seasonal and storm event variability throughout the year. A two end member mixing analysis (EMMA) is used to analyze storm flow conditions versus baseflow conditions, and a predictive model is presented that is used to predict peak springflow based upon rainfall totals. A detailed water budget analysis and comparison to historical data is used to assess groundwater storage and aquifer complexity. The annual data reveal both seasonal and storm event patterns in geochemical and hydrologic conditions of the aquifer. The data indicate distinct responses to storm events. These responses, as well as EMMA results, indicate that storm event flows are composed initially of water formerly stored in the aquifer flushed through the aquifer by incoming meteoric water; this gradually gives way to a mixture of meteoric water and storage water that becomes gradually more similar to pre-storm conditions as discharge recedes to baseflow levels. The highest proportion of meteoric water is coincident with the highest potential for CaCO3 dissolution, indicating that storm events drive dissolution in the LRKA. Water budgeting for the full study period and individual storm events indicate that a large proportion of water in the LRKA is not discharged at Blue Hole Four, but rather is stored in the aquifer or follows another flowpath through the aquifer. Additionally, the higher rainfall totals during storm events tend to increase the proportion of water discharged from the aquifer rather than that stored within it. The predictive model indicates a strong correlation between total rainfall and peak discharge. The results overall indicate two critical times at which contaminant transport may occur: first, any contaminants stored in the aquifer will be flushed out first with storage water as discharge peaks, followed by a period in the falling limb of the discharge hydrograph that coincides with the peak proportion of meteoric water carrying contaminants that entered the aquifer during this event. This study helps to improve understanding of telogenetic karst aquifer processes and evolution, particularly in large, complex drainage basins. Future research is necessary to understand the dynamics of these important groundwater reserves and their response to continuing pressures from climate change, human impacts, and natural processes.

O objetivo desse trabalho foi o estudo da utilização do carbonato de potássio para a absorção de CO2, tendo como principal foco o uso dessa tecnologia para o beneficiamento de biogás em instalações de pequeno e médio porte. O estudo foi dividido em três partes. Na primeira, realizou-se um projeto fatorial, baseado em resultados obtidos por meio de simulação via ASPEN Plus, com o intuito de quantificar a influência da vazão de líquido, da vazão de gás, da concentração da solução e da temperatura do líquido na quantidade de gás carbônico absorvida. Na segunda, foram realizados ensaios de absorção de CO2 em coluna recheada com anéis de Raschig de vidro, utilizando soluções de carbonato de potássio, com objetivo de comparar os resultados obtidos pelo projeto fatorial e estudar o seu potencial para o processo de beneficiamento de biogás. Na terceira, quatro substâncias foram separadamente utilizadas em mistura com solução de carbonato de potássio, de maneira a verificar seu poder como promotores da reação de gás carbônico com carbonato de potássio. Os resultados do projeto fatorial apresentaram a temperatura, vazão e concentração de líquido como as variáveis independentes de maior influência positiva na absorção de CO2, enquanto que a vazão de gás teve influência negativa de baixa intensidade. A quantidade de gás carbônico absorvida em solução sem promotores e em pressão ambiente foi baixa, como relata a literatura. A utilização de promotores possibilitou um aumento substancial da absorção, principalmente com o uso da piperazina. / The objective of this work is to study the use of potassium carbonate for CO2 absorption, aiming to use this technology for biogas upgrade for small and medium scale plants. The study was divided in three parts. In the first one, a factorial design was done, based in results obtained by simulation via ASPEN Plus, to verify the influence of four process variables, namely: liquid volumetric flow rate, gas volumetric flow rate, solution concentration and liquid temperature. Secondly, CO2 absorption experiments were run in columns packed with glass Raschig rings, using potassium carbonate, in order to compare the results obtained by the factorial design and to study the solution\'s potential for biogas upgrade. Lastly, four substances were separately mixed into potassium carbonate solutions, aiming to verify their potential as CO2 absorption promoters. The results of the factorial design presented the liquid temperature, the liquid volumetric flow rate and the solution concentration as the most positively influential independent variables in carbon dioxide absorption, while the gas volumetric flow rate had a negative influence with low intensity. The amount of CO2 absorbed in solution without promoters and in ambient pressure was low, fact that is mentioned by other researchers. The use of promoters allowed a substantial increase in efficiency of CO2 absorption, mainly with the use of piperazine.