Implementing effective and environmentally responsible carbon capture technologies is one of the principle challenges of this century. Successful implementation requires a host of engineering advancements, but also a fundamental understanding of the underlying physics, chemistry, and materials science at play in these highly complex systems. A large body of scholarship examines both current technologies as well as future strategies, but to date little exploration of the surface behavior of these systems has been examined. As these carbon capture systems involve uptake of gaseous CO2 to either aqueous or solid substrates, understanding the chemistry and physics governing the boundary between the two reactant phases is critical. Yet probing the unique chemistry and physics of these interfacial systems is very difficult. This dissertation addresses this knowledge gap by examining the surface chemistry of monoethanolamine and CO2. Monoethanolamine is a simple organic amine currently used in small scale CO2 scrubbing, and acts as an industrial benchmark for CO2 capture efficiency. The studies presented throughout this dissertation employ surface selective techniques, including vibrational sum frequency spectroscopy, surface tensiometry, and computation methodologies, in order to determine the behavior governing aqueous amine interfaces. The adsorption behavior and surface orientation of aqueous monoethanolamine is examined first. The results show monoethanolamine is present at the surface, highly ordered, and solvated. Perturbations to this amine surface from gaseous CO2 and SO2, as well as from liquid HCl, are examined in the remainder of the dissertation. Reactions between the amine and acids are shown to cause immediate changes to the interface, but the interface then remains largely unaffected as further reaction evolves. The studies presented herein provide a needed exploration of the interfacial picture of these highly reactive systems, with implications for future carbon capture materials and design.

La présente thèse contribue à la littérature florissante sur la capture du régulateur en approfondissant notre compréhension des phénomènes de la capture cognitive et informationnelle sous de multiples angles. Le manuscrit est partitionné en trois chapitres. Dans un premier chapitre, je développe un modèle théorique afin d'étudier le difficile arbitrage auquel est confronté un dirigeant politique lorsque celui-ci délègue la régulation du système financier. Le choix opéré par le dirigeant politique dépend de son environnement politique et des caractéristiques du domaine réglementé. Dans un second chapitre, je définis des indicateurs de capture du régulateur et les applique à une base de données construite en rassemblant les pratiques de gouvernances et procédures de 42 agences indépendantes. Ce travail a pour but d’évaluer les prévisions du modèle théorique présenté en chapitre 1. Le troisième chapitre a pour objectif d’expliquer les disparités constatées entre agences indépendantes. Des hypothèses concurrentes sont ainsi testées : les explications politiques versus les explications culturelles et historiques. / This dissertation contributes to the thriving literature in regulatory capture deepening our understanding of both cognitive and information capture along multiple lines. In chapter 1, I develop a theoretical model to analyze the difficult trade-off faced by politicians when delegating the regulation of the financial service industry. The model shows that the principal trades off the superior knowledge of the financial experts against their regulatory bias in favor of the regulated industry. Where the principal comes down on this trade-off depends on how complex the regulatory area is, and on how intense the industry’s preferences are. In chapter 2, I define precise indicators of regulatory capture and construct a data set of 42 agencies that allow me to evaluate the expectations of the model. My results show that the race to sophistication and the powers of financial lobbies seem to have influenced agency design: financial regulators better prevent information capture than cognitive capture. In chapter 3, I test two competing hypotheses to explain the disparities in agencies design: political explanations versus historical and culture explanations. I show that agencies’ level of independence and accountability is explained by the credible commitment hypothesis. This hypothesis however fails to explain agencies level of integrity, appearing commonly low.

The rapid electrification through natural gas in Mexico; the interest of the country to mitigate the effects of climate change; and the opportunity for rolling out Enhanced Oil Recovery at national level requires an important R&D effort to develop nationally relevant CCS technology in natural gas combined cycle power plants. Post-combustion carbon dioxide capture at gas-fired power plants is identified and proposed as an effective way to reduce CO2 emissions generated by the electricity sector in Mexico. In particular, gas-fired power plants with carbon dioxide capture and the sequential combustion of supplementary natural gas in the heat recovery steam generator can favourably increase the production of carbon dioxide, compared to a conventional configuration. This could be attractive in places with favourable conditions for enhanced oil recovery and where affordable natural gas prices will continue to exist, such as Mexico and North America. Sequential combustion makes use of the excess oxygen in gas turbine exhaust gas to generate additional CO2, but, unlike in conventional supplementary firing, allows keeping gas temperatures in the heat recovery steam generator below 820°C, avoiding a step change in capital costs. It marginally decreases relative energy requirements for solvent regeneration and amine degradation. Power plant models integrated with capture and compression process models of Sequential Supplementary Firing Combined Cycle (SSFCC) gas-fired units show that the efficiency penalty is 8.2% points LHV compared to a conventional natural gas combined cycle power plant with capture. The marginal thermal efficiency of natural gas firing in the heat recovery steam generator can increase with supercritical steam generation to reduce the efficiency penalty to 5.7% points LHV. Although the efficiency is lower than the conventional configuration, the increment in the power output of the combined steam cycle leads a reduction of the number of gas turbines, at a similar power output to that of a conventional natural gas combined cycle. This has a positive impact on the number of absorbers and the capital costs of the post-combustion capture plant by reducing the total volume of flue gas by half on a normalised basis. The relative reduction of overall capital costs is, respectively, 9.1% and 15.3% for the supercritical and the subcritical combined cycle configurations with capture compared to a conventional configuration. The total revenue requirement, a metric combining levelised cost of electricity and revenue from EOR, shows that, at gas prices of 2$/MMBTU and for CO2 selling price from 0 to 50 $/tonneCO2, subcritical and supercritical sequential supplementary firing presents favourably at 47.3-26 $/MWh and 44.6-25 $/MWh, respectively, compared with a conventional NGCC at 49.5-31.7 $/MWh. When operated at part-load, these configurations show greater operational flexibility by utilising the additional degree of freedom associated with the combustion of natural gas in the HRSG to change power output according to electricity demand and to ensure continuity of CO2 supply when exposed to variation in electricity prices. The optimisation of steady state part-load performance shows that reducing output by adjusting supplementary fuel keeps the gas turbine operating at full load and maximum efficiency when the net power plant output is reduced from 100% to 50%. For both subcritical and supercritical combined cycles, the thermal efficiency at part-load is optimised, in terms of efficiency, with sliding pressure operation of the heat recovery steam generator. Fixed pressure operation is proposed as an alternative for supercritical combined cycles to minimise capital costs and provide fast response rates with acceptable performance levels.

Geological carbon dioxide (CO2) storage in the United Kingdom (UK) will likely be entirely offshore, which may lead to the production and disposal into the sea of reservoir waters to increase storage capacity, or through CO2-Enhanced Oil Recovery (CO2-EOR). These produced waters have the potential to contain significant concentrations of trace metals that could be of harm to the environment. Batch experiments with CO2, warm brines, and reservoir sandstones were undertaken for this thesis to determine concentrations of 8 trace metals (arsenic, cadmium, chromium, copper, mercury, nickel, lead, zinc) which could be leached during CO2 storage in 4 UK North Sea hydrocarbon reservoirs. A sequential extraction procedure (SEP) was also used to determine the potential mobility of these metals under CO2 storage from mineral phases making up the reservoir samples. The results broadly showed that mobilised trace metal concentrations were low (parts per billion, ppb) in the batch experiments, with the exceptions of nickel and zinc. These metals were associated with carbonate and some feldspar dissolution, with other metals apparently desorbed from mineral surfaces, probably clays. The results of the SEP, however, were a poor predictor of actual mobility with respect to the batch experiments, although useful in determining the distribution of trace metals within the defined mineral phases (water soluble, ion exchangeable, carbonate, oxide, sulphide, silicate). In addition, fieldwork was carried out at Green River, Utah, to collect 10 CO2-driven spring water samples and 5 local aquifer rock samples. This area was used as a natural analogue for CO2-mobilised trace metals from sandstone aquifers. Trace metal concentrations in spring waters were very low (ppb) and batch experiments using Utah rock samples, spring water collected from Crystal Geyser, and CO2 confirmed very low mobility of these metals. The SEP was repeated for the Utah reservoir rocks, but again was not a reliable predictor for actual mobility, other than to confirm that overall bulk concentrations of trace metals was low. Comparison of trace metal concentrations from the batch experiments with data from UK North Sea oil and gas produced waters shows that overall, concentrations mobilised in batch experiments are within the range of concentrations across all North Sea fields reporting their data. However, on a field-by-field basis, some CO2 mobilised concentrations exceeded those currently produced by oil and gas activities. Furthermore, average batch experiment trace metal loads are higher than average oil and gas produced waters, and in some cases exceed international guidelines. Therefore, while the majority of trace metals have low mobility and therefore low environmental impact, this should be assessed on a case-by-case basis. Regular monitoring of dissolved constituents in produced waters carried should also be carried out, particularly in the initial stages of CO2 storage operations, with remedial action taken as required to reduce the environmental impact of offshore carbon capture and storage.

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Rheumatoid arthritis (RA) is a complex autoimmune disease affecting approximately 1% of the population. Multiple factors contribute to the development of RA, with genetic factors accounting for around 60% of the disease risk. Over the last few years, genome-wide association studies (GWAS) have successfully been used to identify regions of the genome predisposing to complex disease. There are now 101 confirmed RA risk loci, but for the vast majority of these loci the causal gene and causal variant remain unidentified and therefore, their function in disease is unexplored. The majority of genetic variants, or single nucleotide polymorphisms (SNPs), associated with disease map to non-coding enhancer regions, which may regulate transcription through long-range interactions with their target genes. The aims of this project were to identify the causal genes within an RA locus, pinpoint the causal variants and elucidate the mechanisms by which the variants modify gene function. Capture Hi-C (CHi-C) was carried out with the aim of identifying long range interactions between disease-associated SNPs and genes in four related autoimmune diseases. Many long-range interactions were identified which implicated novel candidate genes, interactions involving multiple genetic loci which had a common target, and interactions with loci which had previously been implicated in disease. Complex interaction patterns were observed in many of the disease associated loci, particularly in the 6q23 locus which is associated with a number of autoimmune diseases and is the focus of the present thesis. Within the 6q23 locus, associated SNPs lie a large distance from any gene (>180kb) making it difficult to pinpoint the exact causal gene. Results from CHi-C and chromosome conformation capture (3C-qPCR) experiments indicated that restriction fragments containing disease associated intergenic SNPs could display genotype-specific interactions with genes associated with autoimmunity (IL20RA and IFNGR1). Interactions could also be detected with long non-coding RNAs (lncRNAs), The lead SNP in the 6q23 region is in tight LD with eight other SNPs which are equally likely to be causal. Bioinformatics analysis suggested that the most plausible causal SNP in the 6q23 intergenic region was rs6927172, as it maps to an enhancer in both B-cells and T-cells, is in a DNaseI hypersensitivity cluster, shows transcription factor binding and is in a conserved region. Chromatin immunoprecipitation (ChIP) demonstrated binding of chromatin marks of active enhancers (H3K4me1 and H3K27ac) and the transcription factors BCL3 and NF-κB to the rs6927172 SNP target site in Jurkat T-cells and GM12878 B-cells, suggesting the risk allele could be associated with increased regulatory activity. In conclusion, these results show that CHi-C can help identify novel GWAS causal genes with the potential to suggest novel therapeutic targets. For example IL20RA is already a target for a monoclonal antibody which has been shown to be effective in treating RA in clinical trials. This project has also provided compelling evidence that the autoimmune risk variant in the 6q23 locus, rs6927172, is within a complex gene regulatory region, involving multiple immune genes and regulatory elements, such as lncRNAs.

Le broyage réalisé dans un broyeur à billes agité est un procédé permettant de produire des nanoparticules en suspension dense. L’étude réalisée a pour objet l’analyse de l’influence de l’hydrodynamique sur le processus de réduction de taille. La première partie de l’étude a porté sur la modélisation de l'hydrodynamique globale dans ce broyeur en considérant un fluide équivalent de propriétés rhéologiques variables, représentant le mélange des billes de broyage et de la suspension à broyer. Les champs de vitesse, obtenus par simulation numérique directe (DNS), ont permis de déterminer une cartographie des collisions avec leurs caractéristiques et d'en déduire les mécanismes responsables de la fragmentation. A partir de la connaissance des vitesses d'impact et des nombres de Reynolds caractéristiques des collisions dans le broyeur, un dispositif expérimental a été conçu reproduisant, à plus grande échelle, le rapprochement d'une bille de broyage mobile vers une bille fixe. Les profils de vitesse de drainage ont été mesurés par vélocimétrie par image de particules (PIV) sous différentes conditions expérimentales et différentes configurations d'impact. Ces mesures ont permis de calculer les trajectoires de particules fictives dans l'entrefer entre les sphères et d'estimer une efficacité de capture des particules. On observe qu'une augmentation des effets d'inertie de ces particules, en agissant soit sur leur diamètre, soit sur la vitesse de collision, est favorable à leur capture et par conséquent à leur fragmentation. De manière complémentaire, l'examen des trajectoires de particules réelles déposées à la surface de la sphère immobile a révélé que l'efficacité de capture est réduite lorsque le nombre de Stokes des particules augmente. / The stirred media mill is used to produce nanoparticles from dense suspensions. The purpose of our study is to analyse the influence of the hydrodynamics on the fragmentation process. The first part is devoted to the flow modelling in the mill for an equivalent fluid. The constitutive law is accounting for the properties of grinding beads and suspended particles. Velocity fields, obtained by direct numerical simulations, have permitted to analyse the collision characteristics and to determine the major mechanisms leading to fragmentation. By determining the impact velocities and collisional Reynolds we were able to set up an experiment modelling two approaching grinding beads. One bead is mobile while the other is fixed. The flow velocities in the fluid have been measured by PIV for a wide range of conditions. These velocity fields have been used to calculate particle trajectories within the gap between the two beads. This yields to estimate a capture efficiency for particles. We concluded that an increase of the particle diameter or an increase of the impact velocity increases the probability of capture. Additionally, trajectories of deposited particle at the surface of the fixed spheres show that the capture efficiency decreases when the Stokes number of the particle increases.

This study investigated the role of contextual factors in personnel selection. Specifically, I explored if specific job factors such as the wage, training, available applicant pool and security concerns around a job, influenced personnel decisions. Additionally, I explored if the individual differences of decision makers played a role in how the previously mentioned job factors affected their decisions. A policy-capturing methodology was employed to determine the weight participants place on the job factors when selecting candidates for different jobs. Regression and correlational analyses were computed with the beta weights obtained from individual regression analyses. The results obtained from the two samples (student and general population) revealed that specific job characteristics did indeed influence personnel decisions. Participants were more concerned with making mistakes and thus less likely to accept candidates when selecting candidates for jobs having high salary and/or high training requirements.

We live in a busy and complex world, so the ability to focus our attention on relevant information at the expense of the irrelevant is essential in allowing us to avoid distraction. However, it is also important that our attention be captured by external stimuli that, although irrelevant to the task at hand, may nevertheless provide information about important changes to our immediate environment. This capture/orienting of attention is an involuntary, fundamental, and biological mechanism necessary for survival. The present thesis employed event-related potentials (ERPs), the minute responses of the brains electrical activity, to examine how changes in the acoustic environment can lead to the capture of attention. Study 1 examined an ERP component, the P3a, which is associated with the processes that lead to the forced capture of attention by external stimuli. This intrusion into consciousness can be studied using an auditory sequence, the oddball paradigm, which consists of a frequently occurring and homogenous ‘standard’ stimulus. At times, a feature of the standard is changed to form a rarely occurring ‘deviant’. If the extent of change between standard and deviant is large enough, processes associated with attention capture may be activated. Study 1 of this thesis employed a more time-efficient multi-feature optimal paradigm, which allows for the presentation of numerous deviants in one auditory sequence. The standard stimulus was a pure tone. Four of the six deviants were created by changing a single feature of the standard (frequency, duration, increase and decrease in intensity), while the remaining two deviants varied on more than one feature from the standard (environmental sounds, white noise). Results revealed that only the environmental sounds (i.e. animal sounds, human voices, musical instruments) and white noise bursts, elicited the P3a, while the other four deviants did not. Studies 2 and 3 determined whether the attention capture processes associated with the P3a could be observed during the sleep onset and sleep periods, where awareness of the external environment is diminished. For sleep to be of benefit it needs to remain as undisturbed as possible, without constant awakenings by irrelevant external input, however, the sleeping organism must still have the ability to become conscious of possibly relevant input that requires immediate action. In Study 2, a P3a was elicited again following only the environmental sound and white noise deviants across wakefulness and the sleep onset period. Surprisingly, during definitive sleep, the environmental sounds continued to elicit a P3a suggesting that attention capture processes may still remain active during sleep. Nonetheless, only the first 30 minutes of sleep were examined. Study 3 was then conducted to examine the P3a across the entire night. Results revealed that the environmental sounds did, in fact, elicited a P3a during both NREM and REM sleep. The present thesis demonstrates that attention capture mechanisms, observed during wakefulness, are also active during sleep onset and sleep when awareness of the external environment is diminished. This is especially critical because the sleeping organism may be vulnerable to external danger, requiring the immediate ability to orient attention to incoming information, leading to awaking and conscious awareness.

Direct capture of CO2 from ambient air is a developing technology, which is capable of removing CO2 directly from the atmosphere. Moreover, this technology is independent from sources of CO2 emissions. Hence, it can be set up at locations where pure stream of CO2 is needed such as in enhanced oil recovery. In this research, the performance of pelletized and natural limestone for CO2 capture from air in a fixed bed is studied. To compare the performance of sorbents for air capture, the effects of particle type (natural limestone and pelletized limestone), particle size (250-425 µm and 425-600 µm), gas flowrate (0.5 L/min and 1 L/min), and relative humidity, on the breakthrough time, breakthrough shape, and the global reaction rate are examined. Moreover, carbonation decay of sorbents over series of capture and regeneration cycles is studied. If the inlet stream (air) is humidified at 50% relative humidity, but the lime sorbents are not pre-hydrated, an axially non-uniform carbonated bed results. This phenomenon is due to the partial carbonation of sorbents at the first layers of the bed. While there is a competition between CO2 and water to react with CaO, partial carbonation reaction on the surface of the sorbents not only prevents further hydration, but also decreases the reaction rate at the surface. However, in comparison with a dry system where relative humidity was negligible and sorbents were not pre-hydrated, the observed carbonation conversion was higher. The best results were seen from experiments with pre-hydrated sorbents and humidified inlet stream. The smaller sorbent particles had a better performance (sharper breakthrough curve and longer breakthrough time) due to their greater surface area. A gas-solid reaction model was fitted to the breakthrough curves. Since at the beginning of carbonation there is no resistance of the product layer, it can be assumed that the process is reaction controlled. While after formation of the product layer (CaCO3), it becomes diffusion controlled. Results from fitted data also confirmed these conclusions. Moreover, each of sorbent went through 9 cycles and after each cycle the carbonation conversion of the sorbents was measured by TGA and the surface area by BET.