Theses and Dissertations
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Item Open Access Familial variation in personal PM2.5 exposure within a rural Rwandan community pre and post clean energy intervention(Colorado State University. Libraries, 2025) Tanner, Ky, author; Volckens, John, advisor; Carter, Ellison, committee member; Clark, Maggie, committee member; Jathar, Shantanu, committee member; L'Orange, Christian, committee memberExposure to fine particulate matter (PM2.5) from solid fuel combustion is a major determinant of global morbidity and mortality. However, demographic variations in personal exposure remain uncertain across many high-risk populations. Liquefied petroleum gas (LPG) stoves have been proven to emit far less PM2.5 than traditional biomass burning stoves and significantly reduce personal exposures in randomized control trials. However, there is uncertainty surrounding the difference in exposure reductions produced by LPG stove interventions among men, women, and children. This work describes personal PM2.5 exposures and exposure reductions among household members (adult men, adult women, and children) in rural sub-Saharan Africa, where biomass fuel was the primary household energy source, before and during a whole-household energy intervention. LPG stoves were used to replace traditional biomass burning stoves, and solar-based electric lighting replaced traditional kerosene lamps. Personal PM2.5 exposures were assessed using wearable monitors that combined real-time sensing, time-integrated (gravimetric filter) sampling, and continuous location-activity tracking over 48-hr sampling periods. First, the baseline variation in PM2.5 exposures among adults (men and women) and adolescent/pre-adolescent children within two rural Rwandan villages was assessed prior to the introduction of clean energy technology, when all participants still relied on their traditional forms of household energy. Linear mixed models, controlling for household, were used to examine the variation in baseline exposures among family members. A spaciotemporal analysis was also employed to apportion personal PM2.5 exposures into unique time-activity patterns, revealing previously unknown behavioral patterns between the demographics. For the intervention phase of the study, an intent-to-treat (ITT) framework was used to examine the variation in personal PM2.5 exposure reductions achieved by the whole-household energy intervention among men, women, and children within the community. Results from this analysis indicate that interventions for household energy systems, in conjunction with familial lifestyle and behavior modifications, are necessary to reduce personal PM2.5 exposures in rural sub-Saharan African communities.Item Embargo A versatile low-cost platform for particulate matter, volatile organic compound, and noise monitoring(Colorado State University. Libraries, 2025) Molina Rueda, Emilio, author; Volckens, John, advisor; Carter, Ellison, advisor; L'Orange, Christian, committee member; Jathar, Shantanu, committee member; Wilson, Ander, committee memberMillions of people die prematurely each year from exposure to air pollution and other environmental hazards, and many more experience chronic disease. Mortality, morbidity, and other key indicators of adverse health are typically analyzed for large populations using city-, county-, or census track-level exposure data. A more local, or ideally, an individual-level understanding of human exposures would reduce uncertainty significantly and provide more actionable data. With the advent of affordable microelectronics, low-cost instruments for air quality and environmental monitoring are becoming increasingly common and more accessible to the public, but the data-quality gap between reference-grade monitors and low-cost alternatives is substantial. Combining the data-quality standards of reference-grade monitors with the accessibility of new consumer electronics would advance the state-of-the-art in environmental monitoring. This work describes the development and validation of a platform to monitor and collect particle and gas pollutants, and other environmental factors, at a lower cost than established technologies, while preserving the rigor and data-quality objectives associated with reference-grade methods. We developed a platform based on the AirPen, a low-cost monitor for assessing personal exposure to particulate matter and volatile organic compounds. Variations of the platform with different form factors, sensors, and sampling media compatibility were designed, and then tested in the field. Our platform implemented previously validated methods such as NIOSH method 0500 for total particulate matter and EPA method TO-11A for carbonyls. The sampling throughputs achieved in two field studies were considerably higher (5x – 10x) than those typically achieved with conventional instruments within similar timeframes and populations. The spatial and temporal coverage of our results revealed insights on exposure that could be missed by more sparse monitoring. Results from this work demonstrate that new technology can bridge the data-quality gap and address the barriers of entry (e.g., cost, ease of use), to complement the limited regulatory (reference-grade) monitoring efforts currently in place.Item Open Access Experimental investigation of laser-ignited hydrocarbon sprays and droplets(Colorado State University. Libraries, 2025) Lokini, Parneeth, author; Yalin, Azer P., advisor; Windom, Bret C., advisor; Dumitrache, Ciprian, committee member; Van Orden, Alan, committee memberSpray ignition involves complex multiphase interactions wherein atomized fuel droplets undergo evaporation, secondary breakup, and mixing with the oxidizer. These processes result in highly heterogeneous fuel-air mixtures, characterized by significant local equivalence ratio variations, complicating the establishment of consistent and reliable ignition conditions. Additionally, substantial energy losses occur in spray ignition, as a considerable portion of the input energy is consumed by droplet heating and vaporization rather than directly contributing to plasma formation and flame kernel initiation. The presence of turbulence further exacerbates ignition challenges by introducing local velocity gradients and strain that distort or extinguish nascent flame kernels. This dissertation aims to bridge the existing knowledge gaps in spray ignition through systematic experimental investigations under realistic yet controlled laboratory conditions. The research is structured into two complementary components: (1) laser-droplet interactions and droplet breakup dynamics, and (2) laser ignition of fuel sprays. In the first component, experiments focus on elucidating how laser pulse energy and droplet size influence droplet fragmentation dynamics, plasma formation, and species evolution in the breakdown region. Utilizing diagnostics such as shadowgraphy and Laser-Induced Breakdown Spectroscopy (LIBS), droplet breakup regimes, species composition, electron densities, and temperatures are characterized. A novel energy-based metric is developed to effectively distinguish and classify different droplet fragmentation regimes. The experiments demonstrated that low laser energy densities (<~70 mJ/mm3), designated as regime 1, resulted in a single plasma breakdown event accompanied by broadband emission and C2 Swan bands, suggesting weak plasma formation. Conversely, high energy densities (>~70 mJ/mm3), designated as regime 2, resulted in multiple plasma breakdowns that resulted in emission of Hα, O, and N, implying a full laser breakdown in the gaseous reactive mixture. The second component includes laser ignition experiments that were performed in a heptane spray using an Nd:YAG laser to investigate its ignitability. In the first set, Laser-Induced Breakdown Spectroscopy (LIBS) and imaging were employed to quantify Hα/O ratios, kernel size, and kernel number at various locations within the spray. While these parameters generally followed the spray profile, they did not reliably predict ignition. In the second set, OH chemiluminescence, LIBS, and high-speed imaging was utilized to understand the effect of laser energy and ignition location on ignitability. Two distinct modes of ignition failure—short and long—were identified based on kernel extinction time. For the spray conditions studied, ignition was achieved at laser energy of 250 mJ, while long-mode failure occurred at 80 mJ, and short-mode failure at 30 mJ. Optical intensities of OH and CH showed that higher laser energies generated more radical species and sustained the flame long enough to establish stable ignition. Additionally, kernel trajectories extracted from high-speed images showed that ignition is more probable for cases where the spark is generated in or moves into recirculation zone. These findings enhance our understanding of spray ignitability and can inform the development and validation of models for laser or plasma-assisted combustion in sprays. The results presented in this dissertation not only advance the fundamental understanding of spray ignition phenomena but also contribute toward the development of more reliable and efficient ignition systems. The broader significance of this research lies in its direct applicability to practical combustion systems, particularly aero-turbines where dependable ignition and stable flame propagation are essential for safe and efficient operation. Moreover, the insights gained from this work can guide future experimental studies and enhance computational modeling efforts in the field of multiphase ignition.Item Embargo Micro/nano scale modification of titanium surface for enhanced mesenchymal stem cell interactions and antibacterial properties(Colorado State University. Libraries, 2025) Savargaonkar, Aniruddha Vijay, author; Popat, Ketul C., advisor; McGilvray, Kirk, committee member; Bechara, Samuel, committee member; Herrera-Alonso, Margarita, committee memberTitanium has been established as the gold standard for fabrication of implants for orthopedic purposes thanks to their excellent mechanical properties, great corrosion resistance and biocompatibility. However, titanium is bioinert which leads to insufficient osseointegration, leading to implant loosening, bacterial infection and ultimately, implant failure. Better osseointegration can be achieved by fabricating surfaces which are able to better integrate with the tissue whilst preventing bacterial infection. Additionally, blood clotting, while also being the first step of wound healing process, has also displayed enhanced bone formation. Therefore, the surfaces should also be able to encourage blood clotting. To address these challenges, two different surface modifications on titanium were investigated in this dissertation. The first was a fabrication of copper modified titania nanotube surfaces (NTCu). The second approach was nanostructured-micro-porous titanium surfaces (NPTi). The hemocompatibility and ability of the surfaces to promote cell adhesion, growth and differentiation as well as prevention of bacteria adhesion and biofilm formation were investigated. The results indicated that both the surface modifications possess enhanced antibacterial properties, improve cell differentiation to osteogenic lineages and that the NPTi surfaces displayed enhanced blood clotting characteristics, hence being a potential approach for designing orthopedic implants.Item Open Access Evaluating the sustainability of emerging agricultural systems(Colorado State University. Libraries, 2025) Maynard, Reid, author; Quinn, Jason C., advisor; Bandhauer, Todd, committee member; Jathar, Shantanu, committee member; Sharvelle, Sybil, committee memberAs the global community seeks to balance rising demands for food and energy with the planet's ecological limits, stakeholders must scrutinize production systems across sectors for opportunities to innovate and reduce impacts. Foremost among these challenges is the threat of climate change driven by greenhouse gas (GHG) emissions. In order to address these emissions, the agricultural sector will play a role as producers mitigate GHG's associated with essential food production while also rising to meet other decarbonization initiatives such as biofuel usage. To quantify these impacts, life cycle assessment (LCA) is used as a well-established method that captures the flows of resources and pollution across supply chains, translating them into impacts. These LCA results inform stakeholders of ecological tradeoffs and mitigation opportunities. By leveraging more advanced methods to differentiate between locations and to model future conditions, these tools can steer the consideration and development of emerging systems towards eco-efficient outcomes. In this dissertation, LCA is utilized in three phases to evaluate emerging agricultural systems, assessing their impacts and identifying sustainability strategies. In the first research phase, geographically-resolved LCA was applied to compare climate impacts and water usages of new local food production systems across the contiguous United States with a centralized supply chain. Using leaf lettuce as the study crop, hydroponic systems were modeled using building energy demand software to simulate indoor plant factories and greenhouses under different local climate and grid conditions. Additionally, crop modeling software was utilized to simulate seasonal lettuce production on farms at each location. Finally, these localized systems were compared to a modeled conventional system of California field cultivation and shipping. Results across all sites indicate that indoor production systems have substantially higher GHG emissions than the conventional supply chain owing to energy consumption from heating and dehumidification demand. Thus, consumers seeking low-impact options should eat from local farms when in-season and otherwise use conventional supply chains. However, local stakeholders may consider a food-climate-water tradeoff, since indoor hydroponic systems use far less water than outdoor systems. Technology adoption scenarios are also considered to evaluate how heating electrification and decarbonized electricity affect the GHG outcomes of indoor cultivation, providing insights for operators in this emerging sector. Continuing to leverage geographic resolution in LCA, the second research phase considers an emerging biofuel feedstock production supply chain at the field-by-field level. In partnership with a company building a plant to convert ethanol to jet fuel, corn fields across South Dakota and Minnesota were evaluated for the 2023 harvest. Utilizing upstream supply chain modeling and the Daycent biogeochemical soil model, localized cultivation practices were translated into farm-gate carbon intensities. Stochastic modeling was then applied to compare results across hundreds of sample sites to default modeling assumptions typically utilized in biofuel LCA. Results demonstrate that this supply chain, on average, achieves lower GHG emissions than the default model suggests, stemming from local variations in energy usage, agrochemical application, and soil conservation. Further analysis suggests that producers focus on nitrogen fertilizer efficiency and land management initiatives with a particular need to ensure accurate, field-level modeling of soil dynamics. Alongside downstream decarbonization efforts, such cultivation-stage initiatives can contribute to creating aviation fuel that meets clean energy standards. While geography-specific LCA insights are useful to understand agricultural emissions, developments across time are also poised to make significant changes in the sector. Thus, in the third research phase, dynamic LCA (DLCA) methods were applied to the outdoor lettuce cultivation model, incorporating modeled ecospheric and technospheric transformations from the present-day to 2050. Dynamic process modeling was used to evaluate how changing climate could affect crop growth. Meanwhile, background technospheric transformation and on-farm technology adoption were modeled to consider how decarbonizing supply chains and zero-emissions equipment could mitigate life cycle GHG emissions. DLCA baseline results show that 2050 emissions will be substantially reduced compared to present-day assumptions; in particular, the deployment of electrified irrigation, combined with decarbonizing generation, provides a near-term avenue for mitigation. In more optimistic technology change scenarios, emerging technologies like green-hydrogen-derived fertilizer and battery electric heavy machinery could provide further emissions reductions; stakeholders could take steps in the present to support the development and adoption of these systems, enabling ecoefficiency gains in food production. Throughout this work, standard and enhanced LCA methods were employed to evaluate the sustainability of emerging agricultural systems that could one day meet global food and fuel demands. The results of these assessments provide quantifiable estimates that support inter-system comparisons and process improvement strategies. Thus, these methods and results can support decision-making for stakeholders across the supply chain to invest in a more sustainable agricultural future.Item Open Access Development of a hybrid electric organic Rankine vapor compression cooling system for energy system resiliency(Colorado State University. Libraries, 2025) Platt, Bennett Parker, author; Bandhauer, Todd M., advisor; Wise, Daniel, committee member; Quinn, Jason, committee member; Cale, James, committee memberThermally activated chillers, like absorption and organic Rankine vapor compression (ORVC) systems, are solutions to improve efficiency, reduce costs, and meet decarbonization goals in the heating, ventilation, and air-conditioning (HVAC) industry. However, technical limitations prevent these chillers from providing steady cooling power under variable operating conditions. This work presents an extensive investigation of a novel, electrified ORVC system, an innovative approach designed to combine the efficiency and emissions benefits of thermally driven cooling with the on-demand reliability of conventional electric systems. By utilizing both electric and thermally driven compressors in an integrated system, this research addresses the fundamental limitations of purely thermal cooling systems while maximizing the benefits of thermal energy utilization. A thermodynamic and turbomachinery model was developed to evaluate three distinct compressor configurations across diverse operating scenarios. Simulation results revealed that positioning the thermal compressor before the electric compressor (TC1 configuration) provided optimal performance by mitigating the choking limitations of the electric compressor. This configuration demonstrated exceptional performance flexibility, operating effectively across heat inputs from 100 kW to 327 kW while achieving thermal coefficient of performance (COP) values up to 1.6 and electric COP values reaching 18.2—significantly outperforming both purely thermal (COPth = 0.44) and purely electric (COPe = 5.86) baseline operations. To validate the simulation findings, a large-scale prototype test facility was constructed and subjected to extensive experimental evaluation. The experiments confirmed the simulation predictions regarding compressor configuration performance, with only the TC1 arrangement successfully achieving the target 175 kW cooling capacity. Under design conditions, the prototype delivered 176 kW of cooling utilizing 257 kW of thermal input and 20.1 kW of electric input. Parametric studies examined system response to variations in heat supply (85-110°C), cooling delivery temperature (2-14°C), heat rejection temperature (25-39°C), and electric compressor power (19.2-33.9 kW). These investigations revealed substantial operating flexibility but also identified critical limitations, particularly regarding compressor isentropic efficiency and operating map constraints. Part-load performance evaluation yielded integrated part-load values of 7.40 and 0.56 for electric and thermal COP, respectively, though performance at lower capacities was constrained by electric compressor lift limitations. This research demonstrates that hybrid ORVC technology can successfully expand the operational flexibility of cooling systems while maintaining high efficiency across diverse conditions. The findings highlight the critical importance of properly matched compression equipment and identify compressor efficiency as a fundamental determinant of both system performance and operational range. These insights provide a foundation for further research and development surrounding hybrid ORVC technology that can contribute to more cost-effective and sustainable cooling solutions.Item Open Access Single-blind controlled release testing to evaluate the performance of an in-situ methane detection system(Colorado State University. Libraries, 2025) Fasasi, Semiu Temidayo, author; Olsen, Daniel B., advisor; Zimmerle, Daniel J., advisor; Vaughn, Timothy L., committee member; Collet, Jefferey L., committee memberThe accurate detection and quantification of Methane (CH4) emissions from equipment at oil and gas facilities is critical for resolving environmental concerns associated with Greenhouse Gas (GHG). This study presents the evaluation of a proprietary CH4 detection solution deployed at a simulated oil and gas wellhead configuration on a green field site in south Texas. In this study, an automated controlled release rig was developed and used to conduct a single-blind, controlled release test program using a protocol developed specifically for the solution under test. The test program lasted for 57 days and included 5,153 discrete 15-minute reporting intervals with release rates ranging from 0.5 kgh-1 to 37.5 kgh-1, and release durations ranging from 15 minutes to 3 hours. Upon completion of testing, a binary classification scheme was used to evaluate the performance of the solution by comparing the reports from the solution to the ground-truth emissions generated by the controlled release rig. For controlled releases greater than 2.5 kgh-1, the solution showed a true positive rate (TPR) of 86 %, and a false negative rate (FNR) of 14 %. For release rates less than 2.5 kgh-1 the solution showed true negative rate (TNR) of 99.8 %, and a false positive rate (FPR) of 0.2 %. The solution showed a 90 % probability of reporting emissions greater than 5.5 kgh-1 and a 50 % probability of reporting emissions greater than 4.4 kgh-1. The solution performance improved with increasing wind-speed with 90 % and 50 % probability of reporting decreasing to 3.8 kgh-1 and 3.0 kgh-1, respectively, for wind speeds greater than 2 ms-1.Item Open Access Plasma breakdown in sulfur hexaflouride and air mixtures for high voltage switch applications(Colorado State University. Libraries, 2025) Ronzone, Evan J., author; Yalin, Azer P., advisor; Williams, John D., committee member; Simske, Steven J., committee memberHigh voltage spark gap switches are critical components used across a wide range of electrical systems where reliable switching and protection at high voltage is required. Power transmission and generation systems rely on such switches to protect systems in the event of switching surges, while also functioning as switching elements in high-voltage circuit breakers. High voltage spark gaps enable the controlled delivery of enormous amounts of electrical energy in very fast timescales. Such properties make spark gap switches highly desirable for pulsed power facilities such as Sandia National Laboratories Z-Machine. Across all applications, these switches must reliably hold off very high voltages on the order of hundreds of kilovolts, while maintaining accurate function. Switchgear must operate for long periods of time, with minimal maintenance. Spark gaps commonly use dielectric gas to insulate the electrodes and improve performance. Among such gases, sulfur hexafluoride (SF6) has been the preferred choice due to its excellent breakdown and recombination qualities. Sulfur hexafluoride possesses exceptional dielectric strength due to its large molecular size and high electronegativity, which allows it to effectively capture free electrons and prevent avalanche breakdown in high electric fields. Additionally, SF6 demonstrates superior recombination properties, as its dissociation products tend to recombine back into stable SF6 molecules, maintaining consistent gas composition and breakdown voltage over many switch closures. However, SF6 is also an expensive gas which presents significant supply chain challenges. SF6 also presents a major asphyxiation hazard in the event of a leak. Efforts to remove SF6 from current high voltage systems require significant design revisions and are difficult to implement quickly. A possible solution to reduce SF6 usage is to use a mixture of SF6 and zero-air (synthetic air nominally composed of 79% N2 and 21% O2, with trace impurities typically below 1 ppm total) at higher operating pressure. However, such mixtures do not yet have large amounts of data supporting their breakdown properties or long-term reliability. This thesis presents the design of an experimental system that measures the breakdown voltages of zero-air - SF6 mixtures at varying operating pressures and compositions. Long-term measurements of breakdown voltage stability and switch reliability using Weibull analysis are also presented. The theoretical background of Paschen's law is discussed, including linear approximations in high pressure-distance ranges. Significant efforts were undertaken to accurately measure the voltage immediately prior to breakdown by minimizing free variables and losses. New switch designs were created, and significant system alterations were made to improve data collection accuracy. System automation was enhanced to accommodate very long test series which would otherwise require significant manual labor over many days. Results indicate that relatively small concentrations of SF6 in gas mixtures significantly increase breakdown voltage compared to pure air. Furthermore, repeated breakdown testing of these mixtures demonstrates comparable, though slightly reduced, reliability compared to pure SF6. Future investigations examining breakdown products or electrode surface conditions could provide better understanding of the recombination dynamics in these mixed-gas systems.Item Open Access Thermal and optical properties of edge sealed photovoltaic modules(Colorado State University. Libraries, 2025) Durney, David R., author; Sampath, Walajabad, advisor; Sites, James, committee member; Weinberger, Christopher, committee memberAs the global demand for clean energy accelerates, photovoltaic (PV) technologies must evolve not only to improve performance and reduce cost, but also to address sustainability and end-of-life considerations. Traditional PV modules rely heavily on polymeric encapsulants such as Ethyl Vinyl Acetate (EVA), which contribute to long-term degradation mechanisms including acetic acid formation, potential-induced degradation (PID), and recycling challenges. This study presents the design, fabrication, and evaluation of an encapsulant-free Edge Sealed Module (ESM) architecture developed at Colorado State University. The ESM eliminates vacuum lamination and conventional encapsulants by enclosing photovoltaic cells within an air-filled, edge-sealed glass-glass structure, enhanced with nano-textured surfaces for optical and thermal performance. The optical performance of ESMs was evaluated by comparing short-circuit current (ISC) to traditional modules under outdoor conditions using a custom-built In-Situ Data Logger. Results indicate that textured ESMs match the optical output of traditional modules within experimental error. Thermal performance was assessed through open-circuit voltage (VOC) measurements, showing that ESMs exhibit similar or improved thermal behavior compared to traditional counterparts, particularly when enhanced with surface textures that promote internal convective cooling. Ultraviolet (UV) stability of PMMA-based nano-textures was also investigated. While encapsulated samples showed minimal degradation, un-encapsulated textures experienced significant transmission loss and delamination, confirming the need for robust edge sealing to ensure durability. In addition to performance, the ESM design offers a simplified manufacturing process with significant reductions in cycle time, factory floor space, and material costs. Mechanical testing shows increased structural strength compared to laminated modules. These findings suggest that ESMs provide a viable path forward for next-generation PV module design—balancing efficiency, reliability, and sustainability while supporting the Department of Energy's 50-year module lifetime goal.Item Open Access Advanced sublimation source for CdTe photovoltaics(Colorado State University. Libraries, 2025) Tapparo, Marc, author; Sampath, Walajabad, advisor; Munshi, Amit, committee member; Sites, Jim, committee memberThis thesis presents the design, modeling, and validation of an advanced sublimation source for cadmium telluride (CdTe) thin-film photovoltaic (CPV) manufacturing, to improve thermal uniformity, system maintainability, and compatibility with Colorado State University's Advanced Research Deposition System (ARDS). Traditional heater configurations in close-space sublimation (CSS) processes have relied on nichrome (NiCr) heater coils cemented to graphite. These are prone to failure from thermal voids in the ceramic cement, dielectric breakdown, and complex maintenance and procedures. After several iterations a new source design incorporating split-sheath cartridge heaters used in the industry was developed and evaluated to address these limitations. Steady-state thermal simulations in finite element software, ANSYS Mechanical, were performed to assess the impact of heater layout, graphite source geometry, and power distribution on temperature uniformity in the CdTe vapor region. G330 graphite with a thermal conductivity of 107 W/m·K was modeled. The effect of shielding and power output of the heater was included in the simulations. The simulations showed thermally uniform sources all within acceptable limits to meet a ±10% deposition uniformity. The simulations showed that a 1.25″ thick bottom plate produced the most uniform isothermal distribution, with less than 5 °C temperature variation across the region. These results were validated through experimental deposition and profilometry, which revealed ±2.9% thickness variation in CdTe films under typical processing conditions. In contrast to prior CSU designs, such as the cemented NiCr configuration, the split-sheath system demonstrated improved thermal stability, maintainability, and resistance to arcing under vacuum. This work confirms that split-sheath heaters and optimized source geometry offer a scalable and resilient solution for precision sublimation in next-generation CdTe PV manufacturing platforms.Item Open Access Study of exhaust gas recirculation (EGR) on the operation of liquid-fueled gas turbines(Colorado State University. Libraries, 2025) Atomboh, Kingsley Essuman, author; Windom, Bret C., advisor; Bandhauer, Todd, committee member; Wise, Dan, committee member; Herber, Daniel, committee memberGas turbines, one of the main producers of electricity, and propulsion for transportation, are significant contributors to the US greenhouse gas (GHG) inventory. The goal of this thesis is to study the process of removing GHGs (i.e., CO2) from industrial/marine propulsion scale gas turbines by leveraging carbon capture while maintaining low NOx and CO emissions. Recirculating the exhaust gas back into the intake of the gas turbine, in a process termed Exhaust Gas Recirculation (EGR) poses a pathway to reduce the scale of industrial and shipboard carbon capture and storage, where weight, space, power, and cost are significant constraints, by enriching the CO2 concentration in the exhaust. However, the amount of EGR and the associated exhaust CO2 concentrations are limited by the onset of combustion instabilities. This occurs because EGR displaces intake air with oxygen-depleted exhaust, reducing the oxygen available for stable and efficient combustion. Earlier works have studied the incorporation of EGR in natural gas-fired turbines. The industrial and maritime sectors have demonstrated growing interest in integrating carbon capture systems with gas turbines operating on liquid hydrocarbon fuels, including diesel, and emerging sustainable fuel alternatives. This study is the initial attempt to understand EGR limits on gas turbine combustion with liquid fuels through the development of a chemical reactor model (CRN) comprised of a series of joined perfectly stirred reactors (PSR), representing different flame and flow zones within the combustor. The CRN is a numerical investigation tool that provides plenary species composition and temperature data at a fraction of the time and cost of conventional reacting flow computational fluid dynamics (CFD) simulations. Chemical reactor networks (CRNs) typically developed for gaseous fuel applications have shown potential to predict gas turbine emissions and operational limits and have been incorporated into gas turbine technology Research and Development (R&D). Nonetheless, challenges exist with implementing CRN approaches with liquid fuels due to the inherent multi-dimensional nature of liquid fuel evaporation and combustion. To incorporate liquid fuels in a CRN model, a stratification method was employed, where a PSR was created to model a portion of the fuel flow as a lean mixture representing the premixed/vaporized fraction of the fuel in parallel with a PSR operating at stoichiometric mixture fractions to simulate the portion of the non-premixed/vaporized fuel flow and its combustion. The C3 chemical mechanism was implemented in this modeling approach to simulate the diesel fuel chemistry (using a simple surrogate) while incorporating chemical reactions to predict NOx and CO emissions. This approach provided an avenue of control within the reactor network to predict emission levels, which was compared and validated against Solar Turbines Centaur 40 (SoLoNOx combustor) engine test emissions data. Following model validation, Exhaust Gas Recirculation (EGR) was introduced, revealing a decreasing trend in NOx emissions with increasing EGR rates, accompanied by a corresponding rise in CO emissions. At elevated EGR levels, CO concentrations reached thresholds associated with significant combustion instability and eventual flameout. The findings indicate that the SoLoNOx (Dry Low Emissions) liquid-fueled combustor exhibits greater EGR tolerance compared to the conventional liquid-fueled combustor.Item Open Access Exploration of volatile organic compounds and combustion generated pollutants produced by structural fuels during wildfires(Colorado State University. Libraries, 2025) Helfrich, Anna, author; L'Orange, Christian, advisor; Carter, Ellison, committee member; Jathar, Shantanu, committee member; Sullivan, Amy, committee memberEmissions from structural fires in the Wildland-Urban-Interface (WUI) such as carbon dioxide, carbon monoxide, particulate matter, soot and volatile organic compounds (VOCs) remain poorly characterized despite growing concern about their contribution to air pollution. To address this gap emissions were quantified during structural fire experiments conducted as part of the Burning Homes and Structural MAterials (BHASMA) project. More than 70 small-scale experiments were carried out at Colorado State University (CSU) in the summer of 2023 across 19 structural fuels and fuel mixtures representing common building materials. In addition, over 20 large-scale burns were performed at the National Institute of Standards and Technology (NIST) in 2024 using standardized fuel cribs composed of wood, gypsum board, and plastic components. Emissions were analyzed across both pyrolysis and flaming phases, resulting in the identification of over 70 unique VOC species. Synthetic materials—including insulation, flooring, and sheathing—produced elevated levels of hazardous air pollutants such as benzene and styrene, which were largely absent in lumber-only combustion. Emission profiles varied with combustion phase and fuel composition but showed general consistency across fire scales. Increased emissions from crib experiments, with respect to pure wood experiments, were associated with the addition of synthetic materials in the crib's composition. These results indicate that structural materials contribute to a distinct and toxic suite of VOCs, with important implications for human exposure, air quality modeling, and risk assessment in fire-prone WUI communities. Potential toxicological exposure and risk are evaluated using VOC emissions in a Gaussian plume model.Item Open Access Modeling high pressure flow through an orifice with real gas effects(Colorado State University. Libraries, 2025) Dall, Weston, author; Troxell, Wade, advisor; Fankell, Doug, committee member; Eftekhari Shahroudi, Kamran, committee memberMass flow control of compressible fluids is integral to several industry sectors, including aerospace, defense, research, and energy. Control valves are a common method of mass flow control and regulate a wide variety of fluid flows, including in the food industry, chemical processing, oil and gas refinement, fuel admission to engines and turbines, pharmaceuticals, and other use cases. Currently, leading controls manufacturers commonly regulate large volume fluid flow up to around 1000 psia within 2 percent accuracy by utilizing flow prediction equations and calibration. The Isentropic Compressible Flow Equation is one commonly used method of doing this, and for this thesis is used as a baseline for current prediction methodology. In high-pressure regimes (i.e., above 1000 psia), compressible fluids begin to deviate significantly from ideal behavior due to a phenomenon known as real gas effects. This thesis seeks to answer how compressible mass flow through an orifice can be accurately characterized at pressures above 1000 psia. To do this, existing methods and their potential for inaccuracy at high pressure are examined. A more accurate method of prediction utilizing a solver and a large fluid property library is proposed and utilized in conjunction with the existing Isentropic Compressible Flow Equation (a commonly used flow equation) to understand the deviation between the two methods. Significant deviation between methods was found to exist especially among gasses with a less ideal molecular structure. Methane displays a deviation of more than 30% in real mass flow when compared to a baseline made by the Isentropic Compressible Flow Equation. Using the solver, a final method of prediction involving use of "ratio maps" combined with the existing Isentropic Compressible Flow Equation was identified as an accurate method of mass flow prediction given knowledge of the gas flow conditions. This approach shows the capability to solve the problem of predicting mass flow through orifices at pressures greater than 1000 psia. This answers the fundamental question of this thesis and has potential as a high-pressure flow modeling solution for industry and academic applications. Another significant part of the work done in this thesis involves the identification of holes in the existing knowledge of high-pressure flow prediction and regulation. This involves both a study of existing research and determination of areas in which it is not deep and developing a solution to fix the holes in existing research for mass flow prediction. The development of a potential solution allows for the identification of challenges with this strategy and possible improvements to be made on it. In this thesis, this involves mainly involves understanding the existing research done on high pressure flow and the relative lack of 1-2 percent accurate flow modelling for high pressure compressible flow in a control valve context. Solution improvements include items such as accounting for potential viscosity effects, improving the prediction of the point at which sonic flow begins, and general improvements to the tools used to make the flow calculations. The need for real test data at high pressures was also very much emphasized in the process of this thesis. Real test data would prove out the method presented here and offer final validation.Item Open Access Computational fluid dynamics-based modeling of methane flows around oil and gas equipment(Colorado State University. Libraries, 2025) Anand, Abhinav, author; Olsen, Daniel B., advisor; Shonkwiler, Kira B., advisor; Zimmerle, Dan, committee member; Hodshire, Anna, committee memberRecent studies estimate that emissions from oil and gas (O&G) production facilities contribute between 20 to 50% of the total methane emitted in the US; therefore, quantifying and reducing these emissions is crucial for achieving climate goals. Some methane quantification depends on both measuring methane concentrations and converting these to emissions through a modeling framework. Currently, simple atmospheric dispersion models are primarily used to quantify emissions and concentrations, but these estimates are highly uncertain when quantifying emissions from complex aerodynamic sources, such as oil and gas facilities. This investigation uses a CFD modeling approach, which can account for aerodynamic complexity but has hitherto not been used to model methane concentrations downwind of a methane release of known rate and compared against in-situ measurements. High-time resolution (1 Hz) methane concentration and meteorological data were measured during experiments conducted at Methane Emissions Technology Evaluation Center (METEC) on 21st March and 11th July 2024. The METEC site configuration, measured wind data, and controlled emission rates were used as input for CONVERGE CFD to model downwind methane concentration. The downwind modeling was done between 20-70 meters, each from two different points of release in two separate controlled release experiments— one from a separator and another from a wellhead. In these experiments, we found that the CFD model can predict methane concentrations downwind of the release to a good degree. The fractional bias in maximum modeled concentration was under 32%, and the fractional bias in time-averaged mean methane concentration was under 41%. The model evaluated on multiple metrics to assess its performance in estimating methane concentrations at typical fence-line distances (∼30 m). These results help to understand external flows and the ability of CFD models to predict downwind concentrations in aerodynamically complex environments.Item Open Access Techno-economic analysis and life cycle assessment of algal turf scrubbers treating wastewater effluent for renewable diesel production(Colorado State University. Libraries, 2025) Ryland, Ashley, author; Quinn, Jason, advisor; Reardon, Kenneth, committee member; Nazemi, Reza, committee memberAlgal turf scrubbers (ATS) are a promising wastewater treatment technology that can simultaneously remove nutrients from effluent and generate algal biomass for conversion into renewable fuels. This study presents the first integrated techno-economic analysis (TEA) and life cycle assessment (LCA) of ATS systems treating effluent from point-source wastewater treatment plants across the continental United States. A regionally resolved process model was developed using watershed data to simulate nutrient removal and biomass production, with biomass subsequently routed to centralized biorefineries for conversion to renewable diesel via hydrothermal liquefaction. The analysis incorporates non-co-located infrastructure and average transportation distances to reflect real-word deployment logistics. Economic viability was evaluated using a discounted cash flow rate of return model, and environmental impacts were assessed using a well-to-wheels LCA framework. Moreover, the TEA incorporates differentiated nutrient credits for nitrogen and phosphorus removal, enabling a more accurate evaluation of water quality services. Results indicate that ATS systems are effective at nutrient removal, with 75% of modeled sites achieving cost competitiveness for fuel production (< $0.87 per liter gasoline equivalent) when nutrient credits of $42 kg-1 for nitrogen and $321 kg-1 for phosphorus removal are applied. However, only 29% of sites present lower life cycle greenhouse gas emissions below the renewable fuel standard (45 g CO2eq MJ-1), limiting locations of feasible deployment. Nonetheless, ATS systems exhibit lower energy and carbon intensity compared to conventional tertiary treatment technologies, offering a viable pathway toward integrated wastewater management and biofuel production.Item Open Access Controlled testing of next generation leak detection and quantification solutions to evaluate performance and develop consensus assessment metrics(Colorado State University. Libraries, 2025) Ilonze, Chiemezie Okechukwu, author; Windom, Bret C., advisor; Zimmerle, Daniel, advisor; Olsen, Daniel B., committee member; Levin, Ezra, committee member; Pierce, Jeffrey, committee memberReducing methane emissions, a potent short-term climate forcer, is critical for mitigating global warming. The oil and gas (O&G) industry is a major source of anthropogenic methane emissions, and regulations in the U.S. and Canada mandate leak detection and repair (LDAR) programs to mitigate these emissions. Traditional LDAR methods, which includes manually surveying O&G assets with handheld optical gas imaging (OGI) cameras or portable organic vapor analyzers, can be costly and labor-intensive given the vast spatial extent of O&G facilities. However, emerging, next-generation leak detection and quantification (LDAQ) solutions promise a more cost-effective alternative but must demonstrate equal or superior emissions mitigation potential to gain regulatory approval. Standardized controlled testing is essential for verifying this equivalence, yet no widely accepted framework currently exists to achieve this goal. This study evaluates and improves the first known standardized controlled testing protocols designed to address this gap. Two test protocols were developed for the two broad categories of LDAQ solutions: continuous monitors, which operate autonomously over extended durations, and survey solutions, which function over shorter durations with human supervision. These protocols, developed through multi-stakeholder collaboration, were used to test 29 LDAQ solutions (some tested multiple times) at the Methane Emissions Technology Evaluation Center (METEC). METEC is an 8-acre outdoor controlled testing facility that simulates methane emissions from North American onshore O&G equipment. Each survey solution and continuous monitor was tested for a minimum of 3 days and 11 weeks, respectively. Tested controlled release rates were up to 7100 g CH4/h for continuous monitors and 2100 g CH4/h for survey solutions. Key performance metrics, including probability of detection (POD), localization accuracy and precision, quantification accuracy, and survey times, were assessed. Seven solutions were retested 3 to 13 months after their initial tests to examine performance changes over time. Results showed that no single LDAQ solution or solution category achieved optimal performance across all the metrics evaluated. For continuous monitors, only two solutions achieved 90% POD within the tested range, failed to detect ≤ 40% of the controlled releases, and had ≤ 40% of their reported detections classified as false alerts. Camera- and laser-based continuous monitors demonstrated the highest emissions source localization accuracy, with most of them attributing ≥49% of their detection reports to the correct emission source. Quantification uncertainty varied widely, with solutions underestimating and overestimating actual emission rates by factors up to 50 and 46, respectively. For survey solutions, handheld OGI cameras exhibited better accuracy and repeatability in detecting and localizing small fugitive emissions compared to mobile (automobile-/drone-based) survey solutions, although the latter completed emission surveys faster. Additionally, performance improvements were observed with repeated testing, emphasizing the likely importance of regular, independent, and comprehensive evaluations in advancing LDAQ solutions. Findings from these controlled tests, combined with stakeholders feedback and insights from parallel field testing, informed the revision of the protocols to better reflect the application of LDAQ solutions at real O&G facilities. Study findings demonstrates that integrating multiple solutions can complement the limitations of any individual or category of LDAQ solutions. Continuous monitors and automobile-/drone-based survey LDAQ solutions can rapidly detect and narrow-down sources of emissions, enabling targeted follow-up investigations with handheld LDAQ survey solutions. In general, this work contributes significantly to efforts aimed at accelerating regulatory approval and adoption of next-generation LDAQ solutions for methane emissions mitigation through transparent and rigorous controlled testing.Item Open Access Improvement of oxide ceramic materials via cation substitution for thermionic emission applications: connecting cation characteristics to changes in atomistic structure and properties(Colorado State University. Libraries, 2025) Fisher, Liam Eugene, author; Ma, Kaka, advisor; Weinberger, Chris, committee member; Neilson, Jamie, committee member; Bandhauer, Todd, committee memberMy research aimed to improve oxide ceramic materials for thermionic emission applications through strategic cation substitution, focusing on enhancing material properties like thermal stability and electrical conductivity. In thermionic emission applications, low work functions and high thermal resilience are essential material properties for efficient electron emission under high temperatures. Two oxide-based material systems, mayenite electride and strontium vanadate, were selected in the present work, because of their promising low work function, reasonable thermal stability, and economical costs of precursors. But both materials require improvements to realize or increase their applicability in thermionic emission technologies. Moreover, these two material systems possess distinguishing lattice structures from each other and utilize different mechanisms for low work function. Thus, in-parallel investigation into and comparison of the results from these two types of oxide ceramics provide fundamental insights into the interplay between the atomistic structure and cationic substitution. A critical objective of this research is to discover how various cation substitutions affect the lattice structure and how these structural changes subsequently modify key material properties for the thermionic emission application. Different cations were substituted at select sites in mayenite electride and strontium vanadate structures, individually and in dual combinations, to assess their effects on thermal stability and electrical conductivity. The hypothesis was that substituting smaller cations at particular atomic sites might increase thermal stability by altering the lattice parameters, bonding environment, and electron density. The study also investigated how dual substitutions might synergize beneficial effects from individual cations, with a focus on combinations that can potentially balance thermal stability and electrical conductivity. To characterize structural modifications, this research employs Rietveld refinement of X-ray diffraction data to conduct detailed analysis of lattice parameter adjustments and cation disorder, providing insight into the structural intricacies induced by specific substitutions. Additionally, thermogravimetric and electrical conductivity analyses reveal trends in the change of oxidation resistance and conductivity that align with anticipated impacts of certain cations. Results suggest that substituting smaller cations into mayenite lattice significantly increases oxidation onset temperature. In strontium vanadate, substitutions at the A- and B-sites have limits to stability as the material drifts further from the ideal tolerance factor of one, with critical implications for phase stability and oxidation behavior. The calcium substitute for strontium led to a vast improvement in both thermal stability (onset of rapid oxidation increased to a temperature > 1050°C) and electrical conductivity (σ > 3000S/cm). The key findings from this work demonstrate that tailored cation substitutions can substantially improve the key properties of oxide ceramics, offering pathways for material optimization for thermionic applications in harsh environments.Item Open Access Autonomous robot control: integrated control strategies for a mobile robotic arm(Colorado State University. Libraries, 2025) Weinmann, Katrina, author; Simske, Steve, advisor; Chen, Thomas, committee member; James, Susan, committee member; Zhao, Jianguo, committee memberAutonomous robots open up a wide range of potential applications for robotic systems beyond the controlled manufacturing environments where they were originally used. These applications can include agriculture, space exploration, search and rescue, fire-fighting, performing tasks in hazardous environments, personal care robots, and much more. Some of these applications have the potential to replace humans in dangerous environments or improve quality of life for elderly or disabled individuals, thus providing great positive societal impacts. However, the technologies needed for robots to operate safely and autonomously in unstructured environments, and especially when interacting with humans, are still being developed. Designing and controlling autonomous robotic systems is a very challenging problem, with some of the major objectives including efficient autonomous navigation in both known and unknown environments; real-time, dynamic obstacle avoidance; real-time and energy-efficient trajectory generation; and safe operation with and/or in close proximity to humans. While all of these topics have been researched in the field of robotics, existing solutions still have limitations which encourage further developments improving on existing autonomous robotic capabilities. Furthermore, each application and configuration of autonomous robotic systems has a unique set of requirements. In this dissertation, the platform of a mobile robotic arm was chosen for its wide range of potential applications achieved from the combined navigation and manipulation abilities of such a robot configuration. Within the scope of autonomous mobile robot arm control, the following topics were identified and chosen for research: (1) indoor target localization; (2) efficient navigation in partially known environments; (3) integrated control (i.e. coordinated base and arm motion) of a mobile robot arm, including both navigation and trajectory generation and tracking. For each topic, a novel or improved methodology was developed, all relevant to a wide range of autonomous robot deployments. The contributions of this dissertation are as follows: (1) Bluetooth-based homing controller for indoor target localization achieving a mean target localization accuracy of 0.12m or less with various levels of simulated sensor noise; (2) modified artificial potential field-based method for efficient navigation in a partially-known environment and for integrated control of a mobile robot arm improving autonomous navigation success rate and efficiency over existing APF-based methods in environments of varying levels of complexity; (3) real-time many objective optimization-based approach trajectory generation method for integrated motion of a mobile robot arm to reach a desired end-effector configuration, demonstrating a 100% success rate in achieving the desired configuration and reaching the configuration in under 30s in 77% of trials; (4) offline trajectory generation for mobile robot arm end-effector trajectory tracking using a sampling-based combinatorial optimization method to generate integrated motion trajectories (coordinated mobile base and robotic arm motion) achieving over 99% success rate in high accuracy (<5mm position tracking error and <0.1 radian orientation tracking error) end-effector trajectory tracking tested on 500 sample trajectories; and (5) integrated controller design for differential drive mobile robot arm trajectory tracking consisting of a fuzzy logic-based differential drive robot (DDR) controller reducing irregular trajectory tracking errors by 2.4X to 6.8X over existing DDR controller designs, and integrated robotic arm-facilitated DDR base tracking error compensation reducing mean maximum end-effector tracking errors by 18%.Item Open Access Viability and sustainability of desalinating produced water in the oil and gas industry(Colorado State University. Libraries, 2025) Grauberger, Brandi M., author; Bandhauer, Todd M., advisor; Tong, Tiezheng, advisor; Sharvelle, Sybil, committee member; Quinn, Jason C., committee memberUnconventional oil and gas extraction consumes considerable amounts of water, with up to 11 million gallons of freshwater used for the fracturing of a single well. Millions of gallons can come back to the surface of a well as flowback and produced waters, which are collected and disposed of through deep well injection. Water reallocation and reduction of resource waste can be aided by treating produced water from these operations but is rarely practiced. In particular, treating produced water to zero-liquid-discharge allows for management of dry wastes and generates a clean water source as its only other product. Eliminating the disposal of brines from produced water management would eliminate the need for deep well injection, which has shown to be an unsustainable option for produced water management. A major barrier to produced water treatment is the cost and availability of energy for treatment. Other barriers arise from an incomplete understanding of the system. Specifically, environmental and social impacts of produced water treatment are not understood. For example, it is not known if the discharge of treated produced water will have a negative effect on drinking water supplies or flow of rivers and streams. Without solving these challenges, produced water will continue to be disposed into injection wells, wasting the potential to reduce freshwater consumption, and further threatening seismic stability and access to freshwater reserves in oil and gas producing regions. This work completes three major analyses to understand the potential of produced water desalination. First, the accessibility of waste heat from the oil and gas industry, which is limited due to spatial and temporal disparities in waste heat and produced water production, was quantified and compared to energy requirements for produced water treatment. The results show that there is potential for waste heat utilization by membrane distillation, a thermal-membrane desalination technology option, in the oil and gas industry for produced water desalination with appropriate waste heat storage system integrations. The next major evaluation is of the economic and environmental impacts for multiple zero liquid discharge desalination options. Economic results show that the existing technology of mechanical vapor compression is difficult to reliably challenge, in terms of cost. However, environmental emissions can be much improved when using waste heat as an energy source for desalination or when treating with electrodialytic crystallization. Finally, this work evaluates options for zero liquid discharge desalination in the oil and gas industry using a triple bottom line sustainability framework. This framework considers the economic, environmental, and social competitiveness of technologies in multiple stakeholder-preference scenarios, which weight the importance of the three categories in different ratios. Results show that the use of waste heat is paramount to the consideration of membrane distillation as a technology option in the oil and gas industry. Further results show that the comprehensive consideration of economic, environment, and social impacts provide context to overall fit of technology options in the oil and gas industry. More detail of each major objective of this work are shared in the following paragraphs. The use of waste heat has been proposed to reduce the energy footprint of membrane distillation for flowback and produced water treatment. However, its feasibility has not been fully understood for produced water treatment. Accordingly, the third chapter of this work performed systematic assessments through thermodynamic modelling of waste heat capture, storage, and transportation for decentralized produced water treatment at well pads located in the Denver-Julesburg Basin. A wide range of sensible, phase-change, and thermo-chemical storage materials were assessed for their effectiveness at the utilization of waste heat from on-site hydraulic fracturing engines and natural gas compressor stations, in order to overcome the temporal or spatial mismatch between waste heat availability and produced water generation. Results show that the type of storage material being used can have a high impact on the efficiency of waste heat utilization and the treatment capacity of membrane distillation. Sensible storage materials only utilize sensible heat capacities, while phase-change materials have improved performance because they are able to additionally store latent heat. However, sensible and phase-change storage materials lose 11–83% of heat due to conversion inefficiencies caused by their changing temperatures. Thermo-chemical materials, on the other hand, have the highest potential for use because they collect and release heat at constant temperatures. Three thermo-chemical storage materials (magnesium sulfate, magnesium chloride, and calcium sulfate) were identified as those with the best efficiencies due to their elevated discharge temperatures which reduce the energy consumption of membrane distillation. In addition, these materials have high volumetric energy storage density, which enables capture and transportation of waste heat from remote locations such as natural gas compressor stations to the well sites, yielding up to 70% reduction in transportation costs relative to moving produced water to centralized treatment facilities at natural gas compressor stations. The third chapter of this work demonstrates the importance of selecting appropriate energy storage material for leveraging low-grade thermal energy such as waste heat to power membrane distillation for decentralized wastewater treatment. With more certainty given in the possibility and logistics of using waste heat for the membrane distillation system in the oil and gas industry, further analysis was needed to evaluate new technologies with existing brine desalination technologies in terms of replacement potential. Four technologies were considered: mechanical vapor compression with a crystallizer, electrodialytic crystallization, membrane distillation with a crystallizer using electrical heating, and membrane distillation with a crystallizer using waste heat. The fourth chapter of this work evaluates the economic and environmental competitiveness of said technologies. Zero liquid discharge desalination has garnered considerable attention for its potential to mitigate the impact of water scarcity while minimizing environmental consequences associated with ill-managed brine wastes. In the fourth chapter of this work, the economic and environmental competitiveness of an electrodialytic crystallization system designed in recent works was evaluated. It was found that when compared to existing zero liquid discharge technologies, electrodialytic crystallization could compete economically with the potential to reduce costs of zero liquid discharge by over 60% in optimal conditions. However, this high economic competitiveness is not consistent in more conservative operating scenarios. Furthermore, electrodialytic crystallization has 42% lower global warming potential than existing technologies. Scenario and sensitivity assessments completed in this chapter identify the operating parameters of electrodialytic crystallization that greatly affect economic and environmental impacts. Most notably, improvements to the cost and performance of ion exchange membranes will provide the highest benefit to electrodialytic crystallization competitiveness. With appropriate concentration of future research on these high-impact areas, the economic and environmental viability of electrodialytic crystallization should continue to increase in the coming years and electrodialytic crystallization will compete with existing zero liquid discharge technologies to provide a low-cost, efficient, and low-impact replacement to existing technologies. This chapter also shows the limited viability of membrane distillation with a crystallizer in replacing existing zero liquid discharge technologies due to high costs. In either case of electrical heating or waste heat use for membrane distillation, energy costs or infrastructure costs stemming from high energy intensity of membrane distillation result in costs far exceeding those of existing technologies. Through economic and environmental analysis expand the understanding of the potential for technologies to reach industrial application, further analysis can be leveraged to evaluate the fit of technologies into specific applications based on multiple stakeholder perspectives of the system needs. In the fifth chapter of this work, technology options were qualitatively evaluated under a stakeholder-informed triple bottom line sustainability perspective Chapter 5 of this work evaluates proposed technical solutions to produced water desalination and considers the additional economic, environmental, and social barriers that exist within the oil and gas industrial system. The consideration of these three impact areas (i.e., economic, environmental, and social) are defined as the triple bottom line considerations. The drivers, pressures, states, impacts and responses framework, first developed by the European Environmental Agency and later updated by the United States Environmental Protection Agency, was used to support the work of chapter 5 by organizing broad system considerations collected from stakeholder-generated literature into an orderly and approachable list of system indicators to evaluate technology compatibility within the applied system. System indicators are quantified, and overall system compatibility scores are calculated based on a variety of stakeholder preference scenarios. The results show that, given current models, emerging technologies have the potential to compete with existing zero liquid discharge technologies when applied to the oil and gas industry for produced water desalination under applications where stakeholders have low economic preference. Careful consideration of stakeholder preferences is necessary because technologies rank differently based on weightings of economic, environmental, and social impact importance. In summary, through thermodynamic and system modeling, techno-economic analysis, life cycle assessments, and triple bottom line sustainability considerations, four zero liquid discharge desalination technology options for the oil and gas industry (i.e., mechanical vapor compression with a crystallizer, electrodialytic crystallization, membrane distillation with a crystallizer using electrical heating, and membrane distillation with a crystallizer using waste heat) were evaluated for the Denver-Julesburg Basin in Northern Colorado. Overall, development of ion exchange membranes with improved performance for electrodialytic crystallization and developments in lowering membrane distillation energy intensity will determine the future economic competitiveness of electrodialytic crystallization and membrane distillation, respectively, as desalination technology options over mechanical vapor compression. However, when evaluating triple bottom line sustainability, results show potential for applications where there is lower preference to economic performance. In such applications, electrodialytic crystallization and membrane distillation with a crystallizer using waste heat consistently compete with mechanical vapor compression-based systems. Further understanding of the applied system needs and stakeholder preferences will determine overall applicability of technologies into the system.Item Embargo Backyard to battlefield: multifunctional medical foam for enhanced wound management(Colorado State University. Libraries, 2025) Stoner, Amelia, author; McGilvray, Kirk, advisor; Wong, Sing-Wan, committee member; Pezzanite, Lynn, committee memberAcute open wounds as a result of traumatic injuries are a prevalent issue for civilians and military personnel across the world. Unfortunately, advanced hospital care for these severe injuries is not always readily available, leaving the morbidity and mortality outcomes of people who suffer these injuries to rely on primary wound care, hopefully applied before it is too late. A complete understanding of traumatic injury's effect on the body remains elusive. However, known complications include hemorrhage and infection of wounds if not treated quickly and effectively. Many primary wound care products exist, but few can perform more than one function. For example, packing a wound with gauze can help stop bleeding, but will not do anything to combat infection. Thus, this work sought to generate a multifunctional therapeutic approach to primary wound care that includes bleeding (tranexamic acid) and infection (vancomycin) control agents delivered through a biopolymer carboxymethyl cellulose foam. This non-solidifying, volume-filling foam was hypothesized to improve the quality of care for those who sustain open wounds from traumatic injuries, especially those who are injured in rural or austere environments without immediate access to advanced care. This work is comprised of four aims that will contribute to the field of emergency wound care. The first aim included generating and characterizing the base foam responsible for delivering selected bleeding and infection control therapeutics topically to the wound. 200% tunability in temporal stability and volumetric expansion was demonstrated, indicating precise control over physical properties. The second aim was to evaluate the in vitro safety of the foam through monolayer live/dead staining of fibroblasts, one of the most prevalent cell types in skin. The foam and its constituents were found to be non-cytotoxic to both murine and human fibroblasts in vitro, indicating base-level safety of the material and potential for successful in vivo experimentation. The third aim focused on in vitro/ex vivo efficacy evaluation of antifibrinolytic and hemostatic properties of the foam on ovine blood with the chosen bleeding control therapeutic. Delivery with the foam demonstrated low clot lysis rates and mechanically robust blood clot rheology compared to other treatment formulations, indicating potential for successful in vivo experimentation in future work. The fourth and final aim evaluated the foam's in vitro/ex vivo antibiotic efficacy on methicillin-resistant Staphylococcus aureus with the selected infection control therapeutic. Delivery with the foam demonstrated 3-4 log bacterial killing of methicillin-resistant Staphylococcus aureus, indicating potential for successful in vivo experimentation in future work. Together, these aims provide novel preliminary data crucial to the product development process and in vivo implementation of the foam as a staple of primary wound care in acute open traumatic injuries.