VictorJuiz/thesis huggingface dataset:
Metallurgical Processes for Extraction of Strategic Materials from Bauxite Residue and Ionic Clays
Keywords: Bauxite Residue
Ionic Clay
Metallurgy
Rare Earth Elements
Scandium

The global demand for strategic materials, such as scandium and rare earth elements (REEs) is increasing with growing adoption of modern and environmentally sustainable technologies, necessitating the adoption of novel resources to ensure supply. Two metallurgical processes are developed towards the goal of providing alternate sources for these materials that are less environmentally damaging and reagent intensive than currently employed methods: bauxite residue and ionic clay.Bauxite residue is a byproduct of aluminum production, and is a potential resource for iron, aluminum and scandium. Carbothermic smelting – acid baking – water leaching is investigated for the recovery of these materials. Carbothermic smelting recovers 99% of iron as crude metallic iron, which can be separated from slag that contains aluminum and scandium. The slag is treated by acid baking – water leaching, to convert scandium and aluminum to soluble sulfate species, allowing recovery. The process is optimized to achieve 99% scandium and 47% aluminum extraction. The production of solid leaching residue is avoided by employing thermal desulfation to remove 84% of residue sulfur content, allowing recycling as smelting flux. Ionic clays are formed by the natural weathering of REE-bearing minerals and the adsorption of the liberated REE ions onto clay surfaces. A desorption–precipitation process is developed to extract REEs from ionic clays. Desorption, employing ammonium sulfate and active pH control, is developed to efficiently extract REEs. Mechanistic testing demonstrates that REE adsorption/desorption occurs according to physical ion exchange adsorption, and surface complexation chemical adsorption, with the relative importance of these mechanisms depending on pH. Using ammonium bicarbonate solution to both raise pH and introduce carbonate ions in the system enables the sequential precipitation and separation of co-extracted impurities, then a mixed REE-carbonate product. The precipitation characteristics of real leachate solutions are tested experimentally and thermodynamic calculations are used to further investigate the precipitation mechanism. These two processes present potential alternatives to traditional sourcing of strategic materials. In addition to demonstrating the potential technological viability and enhancing process efficiency, this work explores and describes the underlying physicochemical mechanisms, allowing this work to inform future efforts to develop processes for responsible strategic materials sourcing.
Socio-emotional Modulation of Pain Circuits and Behaviour
Keywords: Pain
Sex difference
Social interaction

Painful experiences are personal, subjective, complex and do not always match the level of noxious input experienced. Instead, pain is influenced by several psychosocial factors that can enhance or inhibit the perception of pain. To effectively study pain, the role of the social context needs to be clarified. These studies aimed to deconstruct the roles of social context, sex, and hormonal mechanisms in the social modulation of pain. Social interactions result in the physiological release of hormones, which can be rewarding or stressful depending on context, hormonal release, and receptor dynamics. Here, I carried out several experiments to further understand the complex relationships between social context, sex, social interactions, and their effects on pain. In the first study, I demonstrate the role of glucocorticoid receptors (GR) in suppressing emotional contagion in mice in an unfamiliar social context. Stranger dyads exhibit significantly elevated GR activity in the prelimbic cortex of the mPFC. Acute inhibition of GR in the prelimbic cortex was sufficient to elicit pain contagion in strangers, while their activation prevented pain contagion in cagemate dyads. Together these findings provide novel evidence towards the neural mechanism underlying the prevention of pain contagion. In my second study, I examined the role of mu, delta, and kappa opioid receptors in modulating social approach behaviours towards a sibling in pain. Systemic blockade of opioid receptors (MOR, DOR and KOR) all reversed social preference for a female sibling in pain. Pharmacological inactivation of the mid cingulate cortex reversed social approach preference behaviour towards a sibling in pain. In my final study, I demonstrate that social interactions reduce pain and anxiety behaviours in reunited female sibling mice. In female sibling mice, c-fos was elevated in the oxytocinergic neurons of the PVN, cells within the PAG and reduced in the basolateral amygdala compared to mice paired with a stranger or tested alone. Together these findings point towards distinct modulation of pain-related behaviours due to social context.
A New Search for Low-mass Dark Matter and an Examination and Reduction of the Uncertainty due to the Photoelectric Absorption Cross Section using a Cryogenic Silicon Detector with Single-charge Sensitivity
Keywords: Dark Matter
Particle Physics
Photoelectric Absorption Cross Section
Semiconductor Crystal Detectors

Many astrophysical observations point to the abundant existence of dark matter (DM) in the universe composed of particles beyond the Standard Model. However despite numerous experiments using different techniques, DM particles have yet to be directly observed. The Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB experiment will employ silicon and germanium crystal detectors operated at temperatures as low as 15~mK to probe DM interactions using phonon and ionization signals. Recently, R\&D; facilities have developed gram-sized high-voltage eV-scale (HVeV) silicon detectors that achieve single-electron-hole-pair resolution. By probing effective DM-electron interactions, these devices can be used for searches of low-mass DM candidates. This dissertation presents a DM search experiment known as HVeV Run~2 that employs a second-generation HVeV detector operated in an above-ground laboratory at Northwestern University (IL, USA). Energy spectra are obtained from a blind analysis with 0.39 and 1.2\,g-days of exposure with the detector biased at 60 and 100\,V, respectively. The 0.93~gram detector achieves a 3\,eV phonon energy resolution, corresponding to a world-leading charge resolution of 3\,\% of a single electron-hole pair for a detector bias of 100\,V. With charge carrier trapping and impact ionization effects incorporated into the DM signal models, the resulting exclusion limits are reported for inelastic DM-electron scattering for DM masses from 0.5--$10^{4}$\,MeV$/c^{2}$; in the mass range from 1.2--50\,eV$/c^{2}$ the limits for dark photon and axion-like particle absorption are reported. Several DM search experiments, including HVeV Run~2, are sensitive to low-mass DM candidates that rely on the temperature-dependent photoelectric absorption cross section of silicon. However discrepancies in the underlying literature data result in dominating systematic uncertainties on the DM exclusion limits. In order to reduce these systematic uncertainties, this dissertation presents a novel method of making a direct, low-temperature measurement of the photoelectric absorption cross section of silicon at energies near the band gap (1.2--2.8\,eV).
Mode Choice Modelling Subject to Challenges Coming from Input Data Sources
Keywords: Choice Model
Consideration Set
Data Challenges
Logit Model
Mode Choice Behaviour
SP Choice Uncertainty

Mode choice modelling is a crucial component of any demand modelling process and also a major standalone tool for policy analyses. Developing a robust mode choice model requires accurate and comprehensive data regarding different aspects of travel. However, collecting and accessing such data is almost impossible in practice. There are various sources of input uncertainty and data challenges that can contribute to uncertainty of predicted forecasts of travel demand. These challenges are often neglected in modelling practices. This thesis focuses on providing understanding and developing techniques to address selected sources of data uncertainty and challenges in the mode choice modelling context. The objective is to obtain more accurate forecasts and consequently to produce more precise policy measures and investment decisions. This thesis presents a set of empirical models for modelling mode choice behaviour, each focusing on a specific research avenue. First, a modal shift investigation is conducted as a case study, using a survey designed to capture the effectiveness of a TDM program. Next, a novel model of joint revealed preference and stated preference (RP-SP) datasets is estimated to further mitigate uncertainty and bias from the stated preference survey using an elicited confidence rating dataset. Then, an interesting joint consideration set formation model and discrete mode choice model is estimated using elicited consideration set data to capture the choice set formation process. Next, another methodology is developed to capture the probabilistic choice set formation process (without any elicitation data involved) using a novel semi-compensatory framework that combines the Independent Availability Logit and implicit Constrained Multinomial Logit models. And finally, a unique model is estimated to investigate potential mode shift behaviour using a choice-based sample of commuter rail passengers. The proposed methodology jointly models rail station access mode choice and the choice of switching to alternative modes using a Generalized Extreme Value with an endogenous latent variable model. The developed models offer useful insights into understanding mode choice behaviour and policy implications of the outcomes.
Racial Capitalism, Precarity, Necroprotraction and Sports Tourism: A Critical Feminist and Anti-Racist Ethnography of a Martial Art Destination Training Camp in Thailand
Keywords: Intersectionality
Martial Arts
Necroprotraction
Racial Capitalism
Sports Tourism
Thailand

Martial art destination training camps are an emerging trend in sports tourism in which predominantly affluent western tourists travel to practice martial arts in their country of ‘origin’, such as Muay Thai in Thailand. To sell their services, destination training camps promote the commodification of race (through relations of power and otherness) and exoticness (through sea, sand, sun and ‘land of smiles’), the consumption of ‘authenticity’, and opportunities to cultivate the body. In this dissertation, I present findings from my two-and-a-half-month embodied institutional ethnography of King Cobra Muay Thai, Phuket, Thailand (Ethical Approval #36703), which consisted of a critical feminist discourse analysis, participant observation and interviews with Thai camp workers and sports tourists. This camp caters to an affluent, mainly white, western demographic because all the training is in English, it is expensive, and it requires spare leisure time and the ability to travel. Specifically, guided by critical race and gender studies, theories of authenticity and biopedagogies, surveillance and space studies, I demonstrate that camps like King Cobra reify global structures of racial capitalism, which in turn leads to physical, emotional, and economic precarity for Thai local workers. Sports tourists who attend King Cobra to work on their bodies do so because they have embraced racial capitalism and neoliberal biopedagogical practices, vis-à-vis consuming ‘authentic’ Thai ‘Others’ in an ‘exotic’ eastern locale. Unfortunately, a full life of training and working at the camp precipitates necroprotraction (dangerous long term health consequences) for local Thai trainers. I argue that a complete re-thinking of western tourist consumption, which the destination tourist camps reproduce, is needed. Based on my findings, I argue for moving towards ethical sports tourism by challenging global structures of racial capitalism that undergird this industry and suggest the possibility of alter-camps. In this dissertation, I have worked to re-centre local Thai voices from the margins so as to de-centre western colonial camp industries’ and tourists’ desires that continually act to commodify Othered global spaces for their own profit and pleasure. I believe that this dissertation contributes to the disciplinary fields of Physical Cultural Studies, Leisure and Tourism Studies, and Intersectional Studies.
Structural Insight into V-ATPase Regulation
Keywords: CryoEM
V-ATPase
Yeast

Vacuolar-type ATPases (V-ATPases) are membrane protein complexes that function as proton pumps. V-ATPases acidify the intracellular compartments of all eukaryotic cells, making them essential for many basic cellular processes including protein biosynthesis, intracellular trafficking, and receptor mediated endocytosis. In higher eukaryotes, many V-ATPase subunits have multiple isoforms that are expressed in an organelle, cell, or tissue-dependent manner. Aberrant V-ATPase activity and mutations in specific subunit isoforms are associated with numerous diseases. V-ATPase activity can be switched off and on through reversible dissociation of the ATP hydrolyzing V1 region and the proton pumping VO region. Understanding how V-ATPase activity is regulated and how different isoforms influence V-ATPase activity would improve our understanding of the widespread functions of V-ATPase in the cell and guide the design of therapeutics that target V-ATPase.
Structure, Dynamics, and Therapeutic Potential of ATP Synthase
Keywords: ATP synthase
bioenergetics
cancer
cryoEM
protein complex
tuberculosis

Found in mitochondria, chloroplasts, and bacteria, ATP synthases are rotary enzymes that use energy from respiration to generate adenosine triphosphate (ATP). The dumbbell-shaped macromolecular complex consists of a soluble F1 motor and a membrane-embedded FO motor connected by a shared central rotor. Studying the molecular mechanism of both motors and how they are coupled together to form a functional enzyme is critical for understanding bioenergetics and respiration. In this thesis, single particle electron cryomicroscopy (cryoEM) was employed to investigate the structure, dynamics, and therapeutic potential of ATP synthase. To improve cryoEM sample preparation and data storage, a grid freezing device and a movie storage file format were developed. High-resolution structures of both mitochondrial and bacterial ATP synthases demonstrate how proton translocation across the membrane via two proton half channels in the FO region drives rotation of the rotor. The dimeric mitochondrial ATP synthase structure also explains how the enzyme forms dimers, bends the mitochondrial inner membrane, and produces cristae—the characteristic structure of mitochondria. Structures of ATP synthase during rotary catalysis illustrate how the enzyme deforms under strain to achieve efficient coupling of the F1 and FO motors. Additionally, structures of ATP synthases bound to the tuberculosis drug bedaquiline and the antileukemia compound apoptolidin highlight the potential of ATP synthase as drug targets for treatment of bacterial infection and respiration-dependant cancer. Together, our results uncovered fundamental mechanisms that enable function of this fascinating molecular machine and explored how medicines targeting the enzyme might be harnessed to benefit human health.
Influenza and Avian Influenza in Urban Bangladesh: Live Poultry Exposure, Seasonality, and Pandemic Risk at the Human-poultry Interface
Keywords: Avian Influenza
Global Health
Influenza
One Health
Zoonoses

Influenza causes a substantial global burden, and reassortment between circulating human and avian influenza viruses poses a threat for pandemic emergence. The public health risks posed by pandemic influenza are particularly high in Bangladesh where dense, rapidly urbanizing populations and intensifying poultry production sectors are bringing humans and animals in closer contact. Using a One Health approach, this dissertation presents three studies on the epidemiology of influenza at the human-poultry interface. The first study describes the development and population representativeness of a probability-based mobile phone survey measuring live poultry exposure in Dhaka City Corporation (DCC), Bangladesh. The mobile phone survey achieved a relatively high response rate (52.2%) and produced a population-representative sample, requiring only minimal post-stratification adjustment, in this urban setting. Using this weighted survey data, the second study describes the frequency and patterns of exposure to live poultry in live poultry markets (LPMs) and in homes among adults in DCC. Almost three-quarters (74.2%, 95% CI: 70.9-77.2) of the population reported exposure to live poultry in the past year, with the majority reporting weekly contact. Visiting LPMs was more common amongst males (58.9%, 95% CI: 54.0-63.5) than females (40.3%, 95% CI 35.0-45.8), but females reported greater exposure through food preparation. Finally, the third study brought together 10-years of human and avian influenza surveillance data from hospital-based and LPM-based surveillance programs to characterize influenza seasonality at the sub-national level and examine co-seasonality in Bangladesh. Influenza displayed distinct seasonality in humans, with an annual peak in June-July (peak calendar-week: 27.6, 95% CI: 26.7-28.6). However, there was regional heterogeneity in seasonal characteristics, with metropolitan regions peaking earlier and epidemic spread following a spatial diffusion pattern. Comparatively, avian influenza displayed weak seasonality, with moderate year-round transmission. Together, these studies advance our understanding of influenza epidemiology and the potential risks for pandemic influenza emergence in Bangladesh. Results indicate that there continues to be ample opportunity for spillover of avian influenza infections into humans and high potential for viral reassortment between circulating influenza viruses. Study findings can be used by public health practitioners to make informed and actionable policy recommendations to support human and animal well-being.
Cognitive Control Foundations of Interpersonal Functioning
Keywords: Cognitive Control
fNIRS
Interpersonal Functioning
Personality
RDoC

Behaviour regulation is imperative for optimally navigating one’s interpersonal spheres in the pursuit of social goals. Cognitive control, an ability that subserves behaviour regulation at large, appears to be broadly linked to interpersonal functioning. However, the association of specific subcomponents of this construct with distinct aspects of interpersonal functioning have yet to be comprehensively investigated. Therefore, two studies were carried out to examine the associations between two sub-components of cognitive control, as conceptualized within the United States National Institute of Mental Health’s Research Domain Criteria initiative, and aspects of interpersonal functioning, operationalized according to two widely accepted frameworks. Cognitive control subconstructs, one examining in-the-moment processes (Response Selection; RS) and the other examining more deliberative processes (Goal Selection; GS), were operationalized using self-report, behavioural performance, and task-based prefrontal cortex (PFC) activation. Interpersonal functioning was operationalized in Study 1 based on the Five-Factor Model of personality and in Study 2 according to the interpersonal circumplex approach. Results from Study 1 indicated that Neuroticism was associated with lower cognitive control capacity while Extraversion was associated with higher cognitive control capacity across both RS and GS. Higher Agreeableness was related to higher GS but lower RS capacity (i.e., hemodynamic response during cognitive control task). More narrowly defined interpersonal facets subsumed within the broader trait domains were differentially associated with RS- and GS-related PFC activation. Study 2 demonstrated that higher distress due to interpersonal problems was largely related to a lower capacity for engaging in cognitive control across both subconstructs at the levels of self-report and task-based PFC activation. More nuanced and less consistent associations with interpersonal efficacy were found across the two cognitive control subconstructs, their levels of measurement, and sources of interpersonal rating. Furthermore, higher nurturance and lower dominance were generally associated with greater RS- and GS-related PFC activation, albeit with some notable differences across the cognitive control subconstructs, type of interpersonal functioning, and the rating source. Taken together, these findings provide a foundation for advancing the understanding of the ways in which cognitive control processes may support and facilitate interpersonal functioning.
Multisensory Processing in Sensorimotor Control and Planning
Keywords: crossed-hand effect
development
motor planning
multisensory integration
postural control

Integrating sensory and motor signals is essential in perception and control of body posture. It is important for one to perceive spatially accurate and precise body parts to interact within the environment. While much is known about the integration of sensory inputs in locating one’s body part, how motor signals generated from a planned action contribute to posture position estimation is less clear. Another outstanding question is how the reweighting of different sensory information is calibrated based on the stability of the sensory signals. The objective of this dissertation was to examine these two different but related questions. In Chapter 2, in a series of three experiments, it was found that motor planning had a general effect on posture perception based on a crossed-hand paradigm. In a tactile temporal order judgement (TOJ) task, planning to cross one’s hands increased the error rates and planning to uncross decreased them. The change in error rates, however, was unaffected by the timing of the TOJ task. In Chapter 3, the contribution of visual, haptic and proprioceptive inputs to postural control in adults was studied systematically. When the stability of a sensory input (haptic or proprioceptive) was low, the contribution by such sensory input became limited while those by other sensory input (visual) became more influential. Chapter 4 reported a similar postural control paradigm by comparing younger (3 to 6 years) and older (6 to 11 years) children. Multisensory integration and reweighting were evident only in the older group. These results provided novel insights into the role of motor signals in the perception of posture, and the process of sensory reweighting in postural control in both adults and children.