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Publication Assessing beta cell function in adolescents from discrete C-peptide data(Colorado School of Mines. Arthur Lakes Library, 2025-04)During adolescence there is an increase in insulin secretion in response to a pubertally-mediated reduction in insulin sensitivity. Although insulin secretion rate (ISR) cannot be measured directly, reliable inference of ISR has enabled the use of ISR-based metrics of pancreatic beta cell function. We recently developed a Bayesian hierarchical model (BHM) that incorporates physiological constraints to precisely infer continuous ISR profiles from discrete C-peptide data. By considering the logarithm of ISR as a Gaussian process, we construct physiologically meaningful, nonnegative ISR profiles with credible envelopes. Here, we apply this method to infer ISR profiles with uncertainty in an adolescent cohort. Plotting the predicted C-peptide profile obtained from the inferred ISR function against the true C-peptide measurements demonstrates the goodness of the fit. We assess beta cell function with ISR-based metrics including the area under the ISR curve, the maximum secretion rate, and the time to peak secretion. These measures allow for sensitive assessment of beta-cell function in teens with normal and impaired glucose tolerances.Publication CO₂ flooding impact on compositional changes and their effect on elastic properties in oil reservoirs(Colorado School of Mines. Arthur Lakes Library, 2024)This research aims to enhance our understanding of the CO2 interactions with the reservoir oil and brine and, consequently, improve the methods for monitoring and tracking CO2 distribution within the reservoir via P-wave velocity responses in a seismic survey. The research was motivated by the growing importance of CO2 utilization for enhanced oil recovery (EOR) and subsequent sequestration. As for the outcome, this study quantifies the effect of CO2 mixing with reservoir fluids on the elastic reservoir properties to further evaluate the hypothesis from a previous study (Oduwole 2022) that showed that not accounting for compositional changes in oil during CO2 injection would lead to an underestimation of the magnitude of the bulk modulus of the actual response. This study uses a compositional reservoir simulator software, GEM (from Computer Modelling Group, CMG) to simulate CO2 injection and its subsequent effects on the fluid and petrophysical properties, specifically, the reservoir’s bulk modulus and acoustic velocity. This research employed two different fluid systems to compare a heavier oil composition with a lighter composition—both in miscible and immiscible conditions to determine the effect of fluid segregation during flooding. Additionally, the study compares two different approaches that implement Gassmann fluid substitution calculations to estimate bulk modulus and acoustic velocity based on the compositional reservoir simulation results: a black oil approach of Gassmann fluid substitution calculations and a compositional approach. As for numerical modeling and solution, several issues need careful attention. The first one is the fact that CO2 dissolves in brine substantially, and the second item is the grid-orientation effect on the position and distribution of the fluid-displacing front. For instance, in this thesis, a nine-point finite difference approach was implemented instead of a five-point finite difference in the solution of the flow equations. The latter distorts the injection fluid front due to the higher mobility of the displacing phase in comparison with reservoir fluids. In addition, accounting for CO2 solubility in brine delays the displacing front and reduces the concentration of CO2 dissolved in hydrocarbon phases. The findings of this study show that in a three-phase system, the velocity change is predominately influenced by the supercritical CO2 phase. However, the supercritical CO2 phase’s density and bulk modulus are significantly influenced by the components from the oil phase. Heavier oils result in the CO2 absorbing more heavy components, whereas lighter oils lead to the supercritical CO2 absorbing more lighter components. Therefore, the supercritical CO2 phase density varies from the injection site to the production as it mobilizes different components from the oil phase. The changes in saturated bulk modulus, acoustic P-wave velocity, and acoustic impedance are initially significantly different when the Gassmann black oil approach is compared to the compositional approach. These differences are more pronounced for miscible conditions than for immiscible conditions. This is a result of the supercritical CO2 mixing within the oil phase at the displacement front, which the black oil Gassmann approach is incapable of capturing. This leads to an underestimation of the location of the front that is behind the actual front in years for the miscible model and months for the immiscible. Additionally, due to the increasing purity of the injected CO2 as time elapses, the models start aligning with each other despite the changes in the oil density and bulk modulus.Publication Analysis on ASM role in Indonesian nickel production(Colorado School of Mines. Arthur Lakes Library, 2025-04-24)Indonesia now dominates the global supply of nickel, an essential raw material for lithium-ion batteries and stainless steel. Nickel production in the country has more than doubled in the last 4 years, fueled by the government’s "value chain" strategy that drove domestic development of smelting/refining capacity.Publication Tracking a chemical explosion in Iran(Colorado School of Mines. Arthur Lakes Library, 2025-04-28)A massive explosion occurred on Saturday, April 26, 2025, at the Shahid Rajaee port, located near the southern city of Bandar Abbas, Iran. This port is Iran's largest commercial harbor and a crucial trade hub on the Strait of Hormuz [1]. The Strait of Hormuz is well known as a key transit for global oil trade.Publication Energy optimization of supercapacitors and solar battery energy storage(Colorado School of Mines. Arthur Lakes Library, 2025-04)Solar batteries are currently the most commonly used energy storage device for solar panel energy. The downsides of solar batteries though are their limited lifespan, need for maintenance over those years, and negative environmental impacts from disposing of the batteries. An alternative storage option would be supercapacitors. Supercapacitors are known for their longer lifespans, recyclability, and incredibly high charging rates. Their downside though is that with these high charging speeds, they also have high discharging speeds, not allowing for a lot of storage capability. Supercapacitors have a lot of varying factors determined by the materials that they are made from. The two main types are electrochemical double layer capacitors (EDLCs), or graphene-based, and pseudocapacitors, or non-graphene-based. The goal of this research project is to determine from the three options - solar batteries, graphene-based supercapacitors, or non-graphene-based supercapacitors - what is the most efficient method to store solar energy. To achieve this goal, methods used in this project were online research to complete the Research Learning Outcomes (RLOs). All of the calculations are based on sustaining a 2000 square foot house that runs only on solar energy. Energy costs were calculated for obtaining materials and manufacturing each product. Charge and discharge rates were also calculated for each method. Each storage device has its pros and cons. What is being highly considered today is a hybrid between EDLCs, pseudocapacitors, and batteries. The benefits of this combination are maximizing energy and power density and minimizing energy costs.