Now showing items 1-20 of 19258

    • Synthesizing morphology-controlled, high entropy perovskite nanomaterials for solid oxide fuel cells

      McFadden Block, Claire E.; Gonzalez, Sienna; Kim, Youdong; Richards, Ryan M.; O'Hayre, Ryan
      Water splitting is important to a green energy future. Current issues with efficient water splitting include degradation of the fuel cell materials, thermal expansion, and transport through the material. Precise control of nanomaterial composition and morphology are among a materials scientist's tools to design novel low-cost and efficient materials. One way to improve material performance through controlling the composition is to create a high entropy oxide. There has been great interest in high entropy oxide systems because of the ability to combine multiple well-performing cations into one oxide phase, taking advantage of the synergistic effect. This work focuses on Ba, Sr, Ca, Co, Fe, and Mn cations (promising candidates for solid oxide fuel cell electrodes) in the perovskite ABO3 structure. Controlling the synthesis method to achieve single-phase, high entropy materials and maintaining nanomorphology will be discussed in this presentation. Aerogel synthesis is done in an autoclave with pseudo supercritical fluid drying, which allows immediate departure of the solvent and promotes nanomaterial production, resulting in a dry powder. However, subsequent calcination steps to achieve a single-phase oxide often sinters the materials, which removes the desired morphology. Different morphologies are of interest to be used in solid oxide fuel cells because it may improve performance depending on the unique surfaces that are exposed with different free energies.
    • Quantification of the vertical and lateral heterogeneity of distal submarine-lobe deposits, Wolfcamp formation, Delaware Basin, Texas: implications for subsurface lateral prediction

      Jobe, Zane R.; Aguada, Leonela; Desjardins, Patricio; French, Marsha (Colorado School of Mines. Arthur Lakes Library, 2023)
      Submarine-lobe deposits host important archives of paleo-environmental change and are major targets for exploring and producing hydrocarbons. Traditional conceptualizations of submarine-lobe architecture typically exhibit a systematic decrease in bed thickness, grain size, sand content, and amalgamation from proximal to distal and axis to fringe. However, contemporary interests in these submarine environments, driven by petroleum explorations and carbon sequestration endeavors, have unveiled complex lateral heterogeneities. This research presents a quantitative bed-scale analysis of core data from the Gas Technology Institute Hydraulic Fracturing Test Site 2 within the Wolfcamp A Formation, Delaware Basin. The study concentrates on correlating vertical and slant core datasets to delineate the vertical and lateral variability and event-bed architecture within a mixed carbonate-siliciclastic sea-floor fan. Data sets from two wells have been provided for this study: (1) A vertical well and (2) a slant well which include well log data, CT scans, core photos, and XRF data. They are situated 380.6 ft and 1007.2 ft apart for the studied interval, ideal for the quantification of lateral heterogeneity in a significantly short distance. Furthermore, this study investigates the correlation between CT-scan data and rock composition, assessing the utility of CT-scan technology in conjunction with XRF data and compositional proxies—Vcarb, Vsil, and Vclay—in heterogeneity analysis. Additionally, the potential of basic Machine Learning techniques for predicting rock composition is also explored (see Appendix). For the vertical heterogeneity quantification 20 distinct lithofacies were grouped into four Facies Associations (FA-1, FA-2, FA-3, FA-4). Our findings indicate a dominance of Facies FA-3, consisting mainly of pelagites and hemipelagites, followed by Facies FA-1, characterized by Hybrid Event Beds (HEBs), FA-4, composed of hemipelagites influenced by bottom currents and dilute turbidites, and FA-2, featuring turbidite deposits. Among the HEBs, the H3 deposits were the most prevalent, and are characterized by calcium-rich layers at the bottom that progressively transition to silica-dominant layers upwards. Regarding the lateral heterogeneity, this innovative approach highlights considerable differences in event-bed and background layer thickness and composition over relatively short distances. Trends revealed that background layers diminished in thickness approaching the slant well, whereas event-bed deposits became thinner closer to the vertical well. In addition, the interpreted intervals (A and B) were divided into seven depositional lobe elements, defined by compositional, thickness, and stacking pattern variances. These elements - Axis, Off-axis, frontal fringe, and distal fringe zones - demonstrated specific compositional trends. The distal fringes revealed a gradual shift towards silica-rich sediments, whereas the frontal fringes showed a transition to calcium-rich sediments. The central axis and off-axis regions were predominantly characterized by calcium-rich deposits, whereas the frontal fringes showed a transition from calcium-rich to mixed-deposits. The distal fringes revealed a shift from mixed-deposits towards silica-rich deposits. These findings underscore the complex dynamics of sedimentary deposition and its implications for petroleum exploration and developing strategies.
    • Investigating Li-ion battery species dynamics with operando FTIR spectroscopy

      Porter, Jason M.; Meyer, Lydia; Kee, R. J.; Wolden, Colin Andrew; DeCaluwe, Steven C. (Colorado School of Mines. Arthur Lakes Library, 2023)
      Lithium concentration polarization and slow ionic transport hinder fast charging of electric vehicle batteries and can cause cell degradation. Although pseudo-2D (P2D) models capture concentration polarization phenomena during fast charging, experimental measurements of Li-ion concentration have been limited. In this research, we collect operando optical measurements of Li-ion concentration in a graphite/NMC811 full cell with attenuated total reflection (ATR) and Fourier transform infrared spectroscopy (FTIR). To make these measurements, we have developed an optically accessible operando battery that enables real-time measurements of Li-ion concentration during cycling at fast charging rates. We measured significant Li-ion concentration changes during charging at 1C, 2C, and 3C, as well as discharging at C/2 and compared these results with a P2D model. Both the model and the experiments showed Li-ion depletion and rapid Li-ion concentration fluctuations that indicate non-ideal behavior during cycling. This research enables novel Li-ion concentration measurements with FTIR. This research also provides validation of P2D model physics for measuring and analyzing Li-ion concentration polarization at fast charging rates.
    • Production performance of Permian Basin wells and potential for improving oil recovery

      Kazemi, Hossein; Sonnenberg, Stephen A.; Uzun, Ilker Ozan; Düzgün, H. Sebnem; Miskimins, Jennifer L.; Wu, Yu-Shu; Sarg, J. F. (J. Frederick) (Colorado School of Mines. Arthur Lakes Library, 2023)
      The Permian Basin is one of the most prolific oil and gas-producing geologic basins in the United States. The Permian Basin is located in West Texas and Southeastern New Mexico. It has supplied more than 33.4 billion barrels of oil and 118 Tcf of natural gas during a 100-year period (EIA 2022). The ever-increasing water production and usage (e.g., hydraulic fracture stimulation) in the Permian Basin requires produced water management by the operators. Oil recovery from shale reservoirs is a very slow process because of the extremely low permeability of oil-containing pores, with the ultimate oil recovery of around 3 to 8%. Classical waterflooding or gas flooding in unconventional reservoirs is not plausible because of the small pore size and low permeability of the shale matrices. Therefore, creative approaches are needed to increase oil production without relying on large quantities of water injection to enhance oil production, which became the motivation for my research with the objective to integrate geology, fluid flow theory, experimental data, and reservoir modeling to assess production performance and enhance hydrocarbon recovery in the Permian basin. Injecting rich gas or CO2 in such formations in a cyclic fashion (the huff-n-puff process) increases oil recovery substantially but is expensive because of gas compression and injection equipment. Another alternative is to use solvent-containing water in a cyclic fashion (e.g., solutions of ketones and ethoxylated alcohols). Using brine-containing 3-pentanone or surfactant-based solutions results in much additional oil recoveries by cleaning the micro- and macro-fracture flow paths in the stimulated reservoir volume. In this study, the efficacy of injecting a brine solution containing a very small amount of 3-pentanone or a non-ionic surfactant (0.5 to 1.5 percent) determined to enhance oil recovery (EOR). The aqueous EOR huff-n-puff method is more cost-effective and easier to apply than the gas injection huff-n-puff process for the Wolfcamp formation in the Permian Basin. As an initial review of Wolfcamp formation, the production data for wells drilled into the Wolfcamp Formation of the Delaware Basin between 2012 and 2021 was reviewed and organized. A set of bubble maps to identify and visualize cumulative oil, gas, and water production changes was created. The maps showed the maturity of the basin where gas-prone wells are the majority in the northern and northwestern parts, and the southern area is more oil-prone. The wells drilled in Lea, Loving, and East-Reeves counties show the most oil production in one year of production. The gas production is highest in Culberson, North Reeves, and Loving counties. Furthermore, water production is significant throughout the region regardless of the produced hydrocarbon type. Wettability measurements (i.e., contact angles and wettability indices) and the associated water-rock capillary pressures reflect the interactions between the reservoir rock and the pore fluids, which, in turn, strongly affects the distribution of fluids in the reservoir pores. Consequently, I conducted contact angle experiments on five different unconventional reservoir formations across the US and measured interfacial tension (IFT) between oil and brine from the associated formations. Furthermore, I conducted contact angle experiments on the Wolfcamp formation rock samples using ketone and surfactant solutions. For engineering analysis, first, a static geologic model utilizing well-logs and core data was built on Petrel. Subsequently, the aforementioned static model was used to construct a compositional dual-porosity reservoir model using the CMG-GEM commercial reservoir modeling software in conjunction with the experiments. Second, Rate Transient Analysis (RTA) to determine the stimulated permeabilities associated with the hydraulic fracture stimulation was conducted. Next, Wolfcamp PVT report were evaluated and used to build a reservoir fluid model with CMG’s Winprop module. Finally, the compositional reservoir model was history match the field production data to validate the model. After the numerical model was ascertained by history matching, three distinct enhanced oil recovery (EOR) techniques, the huff-n-puff gas injection, ketone solution injection, and surfactant solution injection were implemented for the selected well. Afterward, a sensitivity analysis was conducted to determine the characteristics that had the most significant influence on the reservoir performance of the well in the three enhanced oil recovery (EOR) scenarios. A broad conclusion is that the use of ketone solutions resulted in a significant increase in oil production, while injection rate magnitude and period, soaking period, and solvent concentration affected the magnitude of the incremental oil recovery outcome.
    • Enhancing energy system design and dispatch optimization models for improved climate resilience considerations

      Bazilian, Morgan; Zolan, Alexander J.; Macmillan, Madeline R.; Tabares-Velasco, Paulo Cesar; Newman, Alexandra M.; Lange, Ian; Flamand, Tulay (Colorado School of Mines. Arthur Lakes Library, 2023)
      Energy system planning models have been commonly used for design and dispatch decisions with the goal of cost minimization. Due to the threat climate change poses to energy system operations, however, these models have been gaining popularity for their ability to obtain optimal design and dispatch decisions with resilience considerations. In order to provide informed resilient planning decisions, there is a gap in how current energy system models address long-term uncertainties with respect to climate change. This research explores this gap and how augmentations to existing methods can improve resilient planning in the face of climate change. In this novel body of work, we first conduct a literature review of qualitative and quantitative resilience definitions and, based on our synthesis and observations, propose a working definition and metric to guide the remainder of this work. We then develop a novel scenario generation method combined with a two-stage stochastic program to account for long-term uncertainties including the effects of population and electrification trends on load growth and the impacts of climate change load growth and variable renewable energy availability. From this, we are able to analyze the implications of our novel approach to develop optimal design and dispatch recommendations that account for system resilience. We then broaden the application of our novel methodology to include heating and cooling loads and to evaluate the impacts of long-term uncertainty-informed resilience planning on system design and operations across different climates and building types. Through this body of work, we aim to improve existing energy system planning models by enabling more uncertainty-informed planning decisions that will, in turn, increase the resilience of future energy systems against climate change.
    • Physical beneficiation of the Iron Creek cobalt deposit via flotation

      Anderson, Corby G.; Brevig, Mason; Spiller, D. Erik; Taylor, Patrick R.; Puvvada, George (Colorado School of Mines. Arthur Lakes Library, 2023)
      Cobalt is a critical material as designated by the United States Department of Energy. It is used in electric vehicles as a cathode material and in high strength steels as an alloying addition. The United States currently relies nearly 100% on imports and secondary scrap materials for refined cobalt consumption. Because of this, efforts to establish a domestic supply for cobalt are being pursued. This thesis describes research into sortation and flotation to improve one such effort by Electra Battery Materials through the Iron Creek, ID deposit. Coarse material sortation was tested in order to determine its viability, specifically the viability of XRT sensor-based sorting on Iron Creek material. The sortation testing was successful as low-grade material was able to be separated from rocks that had higher cobalt and copper grades. Rougher flotation testing was used to ascertain the most appropriate conditions for particle size, collector type, and collector dosage. A cobalt grade of approximately 1.8% was achieved with a recovery of nearly 92.0% using rougher flotation. Differential flotation testing was undergone to obtain separate copper and cobalt concentrates by depressing the pyrite at a PH of 11.5. Separate cobalt and copper concentrates were obtained with the copper concentrate having a cobalt recovery of 3.98% and a copper recovery of nearly 20%. Cleaner flotation at high PH was undergone to further recovery cobalt from the differential flotation copper concentrate. Re-grinding to a particle size P80=80 microns aided in the recovery of cobalt to the cobalt concentrate as the final copper concentrate from cleaner flotation had only 0.27% cobalt recovery. Locked cycle testing was also conducted to simulate an industrial flotation operation with results supporting the implementation of an industrial flotation circuit for the recovery of cobalt and copper as separate products. An overall economic analysis incorporating sortation, flotation, thermal degradation, and magnetic separation was constructed. The economic analysis showed that the process was economical and a positive NPV of $35.2 million (+ or – 35%) indicated that the project should be pursued at the industrial level.
    • Chemical beneficiation of cobaltiferous minerals by thermal decomposition of pyrites

      Anderson, Corby G.; Spiller, D. Erik; Aguayo Torrez, Luis Fernando; Taylor, Patrick R.; Puvvada, George (Colorado School of Mines. Arthur Lakes Library, 2023)
      Cobalt is a transition metal whose unique properties make it indispensable in the manufacture of the rechargeable batteries needed for the energy transition. Currently, most of this metal is obtained as a by-product of the extraction of nickel and copper, which is why it is deemed as a critical and strategic metal by the US. However, there are some primary deposits previously considered marginal that have become of great economic interest, such as those found in the Iron Creek area. In this type of occurrence, cobalt is found to be encapsulated within the pyrite lattice, so none of the traditional beneficiation methods could effectively liberate and separate the low cobalt contents from the pyritic matrix. Given the criticality of cobalt and how this metal is embedded in the pyrite (FeS2) structure, it has been proposed that the thermal decomposition of this iron sulfide to pyrrhotite (Fe1-xS) and troilite (FeS) could be an alternative chemical pretreatment that would (i) increase the cobalt content of flotation concentrates by volatilizing part of its sulfur and (ii) transform the initial concentrates into a ferromagnetic product that could be processed in a magnetic circuit to further increase the cobalt contents. Therefore, the following work presents a comprehensive review of the technical and economic feasibility of applying this thermal treatment. To this end, three cycles of experiments were performed on concentrates from the bulk flotation of sulfides and the differential flotation of cobalt. Two cover gases - N2 and CO2 - were used to evaluate the individual effect of temperature, time, gas flow rate, initial pyrite content, and their possible interactions. The results showed the possibility of increasing the initial cobalt grades by 15-17% with the joint production of high-purity sulfur as a valuable by-product. Likewise, results showed the possibility of obtaining a highly porous ferromagnetic material suitable for its treatment in a magnetic separation circuit or for its leaching in a high-pressure vessel. A concentration flowsheet introducing a thermal decomposition circuit was designed and studied to estimate the capital (CAPEX) and operating (OPEX) expenses related to its potential implementation on an industrial scale. A preliminary economic evaluation of the proposed flowsheet yielded positive results, which suggests that the thermal treatment is a highly attractive process for the concentration of the Iron Creek minerals.
    • Applications of smoothness-increasing accuracy-conserving filtering to particle-in-cell data denoising, enhanced multiresolution analysis, and entropy-correction schemes

      Ryan, Jennifer K.; Edoh, Ayaboe; Picklo, Matthew John, Jr.; Fasshauer, Gregory; Wakin, Michael B.; Wu Fung, Samy (Colorado School of Mines. Arthur Lakes Library, 2023)
      The numerical solution of partial differential equations can be very challenging, and while different numerical methods have their own advantages, there is no single numerical method without drawbacks. For example, data arising from Particle-In-Cell (PIC) methods have noise in their numerical solutions owing to the use of finitely many particles. The underlying mesh and corresponding approximation in Discontinuous Galerkin (DG) methods may not be of sufficient spatial resolution to capture localized solution features. Lastly, additional conservation equations such as entropy conditions satisfied by analytic solutions to PDEs are often not satisfied by their discrete counterparts. These deficiencies can be ameliorated by auxiliary techniques and method augmentations. It is the purpose of this thesis to detail three such improvements making use of Smoothness-Increasing Accuracy-Conserving (SIAC) filters, proceeding in order of increasing embedment of SIAC methodologies within the underlying numerical process. First, we detail the application of SIAC filters as denoisers of data arising from PIC simulations and demonstrate how careful tuning of these filters enables noise-reduction in the presence of non-periodic boundaries. Furthermore, in the computation of Bohm speed estimates from PIC data, we show that SIAC filters enable a dramatic reduction in the quantity of PIC data needed. Having applied SIAC filters to the equivalent of finite volume data, we next consider higher-order piecewise polynomial data. Here we show that SIAC filtering can be used to increase the resolution of coarse mesh polynomial data in multiple dimensions and over nonuniform meshes. The resulting enhancement procedure can be viewed within the framework of multiresolution analysis (MRA), making it a natural candidate for application in mesh adaptive DG schemes, where it provides a means of providing more accurate approximations with reduced degrees of freedom as compared to uniformly refined data. To conclude, we break the requirement of applying SIAC methodologies to effectively stationary data by fully integrating SIAC filters with DG numerical methods in the context of entropy-correction schemes. In this application, SIAC filters are applied to ensure that approximations produced by the baseline DG method satisfy additional physically motivated conservation conditions, namely energy conservation, for the duration of a simulation.
    • Cascaded spatial frequency modulation imaging architectures for enhanced resolution multiphoton imaging in photon counting regimes

      Squier, Jeff A.; Scarbrough, Daniel W.; Durfee, Charles G.; Adams, Daniel E.; Paone, Jeffrey R. (Colorado School of Mines. Arthur Lakes Library, 2023)
      SPatIal Frequency modulation Imaging (SPIFI) is a well-established structured illumination imaging technique that has demonstrated enhanced resolution imaging with an extended illumination source and single-pixel detection. This thesis presents work done to improve modulation scan times as well as enhance performance in multiphoton microscopy. The standard implementation of SPIFI uses a spinning disk to impart the spatial frequency modulation onto a line cursor. This architecture is simple to implement in a laser microscope, but is limited in speed and stability due to using a DC motor to spin a patterned disk. As an alternative, the use of polygonal scan mirrors was investigated. These mirrors operate at high speed and stability, but required development of a new SPIFI modulation architecture. The resulting systems showed a reduction in scan times of approximately two orders of magnitude while retaining enhanced resolution capability. For multiphoton modalities which require ultrafast laser pulses, a new method of pulse characterization with SPIFI was investigated. While not completely successful, it led to a method for rapid dispersion compensation optimization as well as a collaboration with promising initial characterization results. The dispersion optimization system coupled with a spinning disk SPIFI system was used to optimize for dispersion through the full microscope system, demonstrating enhanced resolution imaging with pulse energies on the order of nanojoules without significant processing. To pursue further resolution enhancement, photon counting SPIFI was demonstrated using a custom software application to provide a GUI interface and rapid, multi-threaded processing. To achieve stable modulation signals and rapid acquisition, the polygonal scan mirror architecture was used for this multiphoton microscope. Signals were acquired and processed for photon counting at a rate of 500 Hz with a simple USB oscilloscope. With this system, fourth order SPIFI enhanced images were acquired with 1.75 seconds of captured exposure per line and nanojoule pulse energies.
    • Geological storage: risks and operational risk mitigation

      Handler, Bradley P.; Littlefield, Anna; Ayaburi, Felix; Colorado School of Mines. Payne Institute for Public Policy (Colorado School of Mines. Arthur Lakes LibraryColorado School of Mines. Payne Institute for Public Policy, 2024-07-08)
      The use of Carbon Capture and Storage (CCS) as a climate mitigation tool envisions the permanent underground storage of CO₂. The prospects for large scale adoption of geological storage has raised concerns regarding the risks — of property damage, environmental degradation, and to human health — if stored CO₂ were to leak to the surface or into shallow water resources.
    • Introduction: risk mitigation in geological storage of CO₂

      Handler, Bradley P.; Littlefield, Anna; Patton, Lindene E.; Perticari Pesci, Nicolas G.; Ayaburi, Felix; Kulkarni, Siddhant; Shah, Darshil; Colorado School of Mines. Payne Institute for Public Policy (Colorado School of Mines. Arthur Lakes LibraryColorado School of Mines. Payne Institute for Public Policy, 2024-07-08)
      There is consensus that Carbon Capture and Storage (CCS) is an integral activity in the effort to limit global warming and its harmful effects. That contribution requires a significant scaling of CCS operations. To name just one example, the International Energy Agency (IEA)'s most recent Net Zero scenario includes CCS removing one billion tons of CO₂ per year by 2030 and six billion tons by 2050, up from 45 million tons captured and stored in 2022.
    • Degradation of atrazine utilizing triazine hydrolase (TrzN) from Arthrobacter aurescens TC1

      Holz, Richard C.; Diviesti, Karla; Krebs, Melissa D.; Trewyn, Brian; Domaille, Dylan (Colorado School of Mines. Arthur Lakes Library, 2023)
      Triazine hydrolase (TrzN) from Arthrobacter aurescens TC1 is a Zn(II) dependent hydrolytic dehalogenase from the amidohydrolase super family. TrzN has 22 unique substrates. Most notably, TrzN can hydrolytically dechlorinate atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) to its less toxic derivative hydroxyatrazine. Atrazine is a widely used synthetic herbicide which has an extensive list of potential environmental and health concerns. TrzN is a prime target for use in the engineering of biocatalysts for atrazine remediation. However, its catalytic and biochemical properties are not fully understood. This research project provides insight into the catalytic mechanism of TrzN as well as explores the enzymes use in biomaterials for atrazine degradation. Insight into the catalytic mechanism of TrzN has been provided in chapter 2. Three amino acids (Thr325, Glu241, and His274) showed significant catalytic importance. Thr325 is essential for catalysis and data agreed that an essential bond is formed between the Thr325 oxygen and the Zn(II)-bound water moiety which likely stabilizes the water moiety for nucleophilic attack. The mechanism functions based on a two proton transfer system. First the His274 residue removes a proton form the Zn(II)-bound water moiety. The proton is shuttle from His274 to Glu241 which can then form a hydrogen bond with the triazole nitrogen on the atrazine ring positioning it for nucleophilic attack. In chapters 3 and 4, TrzN was immobilized in alginate, sol-gel, and mesoporous nanoparticle (MSN) biomaterials. All of the biomaterials were catalytically active and could degrade atrazine to hydroxyatrazine. Using enzymes as biocatalyst can traditionally be tricky, the inability to recover the catalyst and the enzymes inherent unstable nature makes the process costly and inefficient. Often, the solution to these short comings has been to immobilize enzymes in functional biomaterials. The biomaterials tested in these chapters were all able to be recovered and reused cyclically and over several weeks while maintaining or improving TrzN’s stability. This research herein provides insight into a new avenue to design bioremediation methodologies for the removal of atrazine utilizing TrzN.
    • Design of tunable couplers and investigation of loss mechanisms in superconducting 2D and 3D systems

      Kapit, Eliot; Materise, Nicholas R.; Martin, P. A.; Lusk, Mark T.; Singh, Meenakshi (Colorado School of Mines. Arthur Lakes Library, 2023)
      Superconducting qubits are among the leading physical qubit candidates, with coherence times exceeding 100 microseconds and gate times on the order of tens of nanoseconds. At the hardware level, tunable coupling between qubits has enabled fast, high fidelity two qubit gates, the limiting factor for quantum algorithm gate depth. Tunable couplers have played a significant role in scaling these systems and were instrumental in the first quantum advantage demonstration in certifiable random number generation. Parametric operations, such as beam splitter and two-mode squeezing, are activated by oscillating fields applied to a tunable coupler that are resonant with these red and blue sidebands, respectively. Theoretical modeling tools exist for planar geometries and 3D geometries that use capacitive coupling, but ones for galvanic coupling in 3D have not been realized. This thesis will discuss the design of two novel tunable couplers, one in the planar domain and another in 3D that uses galvanic coupling. In the planar design, a III-V semiconductor heterostructure acts as a tunable capacitor when biased with a negative gate voltage, parting the sea of electrons to modify the geometry of the capacitor. The 3D tunable coupler uses a dc superconducting quantum interference device shunting a 3D cavity and driven at the sum or difference frequencies of cavities to induce beam splitter or two-mode squeezing operations. I will discuss this 3D galvanic coupler and the analysis method developed to estimate beam splitter, two-mode squeezing, and single-mode squeezing rates. The novel materials comprising the 2DEG coupler spurred experiments to estimate its dielectric losses. These experiments led to the design of cavity-based loss metrology systems, with applications in a variety of materials of interest to the superconducting qubit field, namely bulk dielectric loss in indium phosphide, silicon, and sapphire substrates. I will discuss these cavity loss experiments and 2D resonator loss measurements focused on understanding loss mechanisms in 2D qubits. The materials in the 2D studies include niobium and its oxides and hydrides, tantalum, titanium nitride, and silicon. These studies highlight the importance of designing targeted A/B experiments and collecting sufficient loss statistics with tens of resonators per device variation.
    • Mineralogical characterization of tellurium-bearing minerals at the Perserverance VMS deposit, Quebec, Canada

      Pfaff, Katharina; Kasprowicz, Filip A.; Diekrup, David; Monecke, Thomas (Colorado School of Mines. Arthur Lakes Library, 2023)
      The Perseverance volcanogenic massive sulfide (VMS) deposit is a past producing Zn deposit of the Matagami camp, located in the Neoarchean Abitibi greenstone belt of Quebec, Canada. Matagami and the deposits within are known to be significantly enriched in tellurium, a critical element necessary for production of advanced photovoltaic panels. However, little is known on the occurrence, distribution, and deportment of tellurium at Perseverance. The goal of this study is to characterize the mineralogy of tellurium and telluride minerals within the Perseverance VMS deposit to better understand their occurrence at Perseverance and in the VMS environment in general. Scanning electron microscopy based automated mineralogy, field-emission scanning electron microscopy imaging and semi-quantitative analysis, and electron probe microanalysis were used to characterize the tellurium occurrence at Perseverance including mineral chemistry, grain size distribution, spatial relationships, modal abundance, and a conservative estimate of the tellurium grade. Seventeen different tellurium-bearing minerals were identified, including altaite, cervelleite, frohbergite, hessite, kochkarite, lingbaoite, mattagamite, melonite, montbrayite, pilsenite, poubaite, rucklidgeite, tellurantimony, tellurium, tellurobismuthite, tsumoite, volynskite, and native tellurium. Tellurium minerals occur as discrete free grains, inclusions, fracture fills, along grain boundaries, and as large composite aggregates. Grains vary in size from submicron inclusions to coarse aggregates, with over 50 volume% of the tellurides being hosted in grains 15 µm to 150 µm across. A conservative grade calculation based on automated mineralogy data revealed average Te concentrations of 42.5 ppm in high-grade ore samples, with the highest grade sample measuring 305 ppm Te. Tellurium minerals are most frequently associated with sphalerite and pyrite, and to a lesser extent with alteration minerals chlorite, talc, dolomite, and quartz. The close association with ore minerals such as sphalerite is promising for future Te production at similar deposits. Metamorphic overprinting of the Perseverance deposit to greenschist facies is interpreted to have a role in the formation and coarsening of tellurium mineral grains. Sulfides in the deposit are recrystallized and may have purged significant quantities of tellurium and other trace elements from their crystal structure, resulting in the formation of discrete tellurium mineralization and the coarsening of any primary tellurium minerals which might have precipitated during primary ore formation.
    • Magnesia inclusions in lead zirconate titanate

      Brennecka, Geoffrey; Prevoznak, Benjamin D.; Lamberson, Leslie; Reimanis, Ivar E. (Ivar Edmund) (Colorado School of Mines. Arthur Lakes Library, 2023)
      Lead zirconate titanate is a ceramic piezoelectric frequently manufactured with porosity engineered to situationally tune elastic modulus, relative permittivity, and phase transition pressure and/or field. In our case we engineer a 92 % dense ceramic of the formulation Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 (PNZT 2/95/5) using micro-crystalline cellulose. However, inducing porosity can be detrimental to dielectric breakdown strength, mechanical strength, and fracture toughness. In our study we explore how adding MgO as nanoparticles as well as micron sized powder, a hypothesized method of toughening the material, affects electrical properties poling behavior, piezoelectric constant, and relative permittivity. Our limited mechanical data is consistent with fracture toughness increases seen in literature with MgO second phases. However, MgO addition decreased the remanent polarization, piezoelectric constant, and relative permittivity, while increasing the coercive field.
    • Electrochemical oxidation of cyanide and simultaneous removal of heavy metals from gold cyanidation wastewater

      Bellona, Christopher; Figueroa, Linda A.; Delius Cordova, Inge; Vanneste, Johan; Vuono, David Charles (Colorado School of Mines. Arthur Lakes Library, 2023)
      Cyanide is widely used in the gold mining industry to extract gold from different gold-bearing ores and as a result gold cyanidation process wastewater can contain high amounts of cyanide as well as other heavy metals that can pose risks if released to the environment. Electrochemical methods such as electrooxidation have been shown to effectively treat cyanide contaminated wastewater. However, past studies have largely focused on cyanide oxidation and metal recovery using synthetic solutions which may not accurately represent conditions of mining process waters. In the present study, the electrochemical destruction of cyanide and simultaneous removal of heavy metals using a graphite anode and copper cathode under alkaline conditions was investigated. Batch experiments were conducted on synthetic and real gold process wastewaters. First, the kinetics of cyanide electrooxidation were studied by examining the effects of applied voltage, electrolyte composition, and copper concentration. The effects of electrolyte composition were of particular interest as several gold cyanidation facilities have shifted towards using partially desalinized and even raw seawater for their processes. Results indicated that cyanide follows a first order reaction with respect to CN- ions for most wastewater samples examined. In addition, increased voltage and NaCl concentrations lead to an increase in the rate of cyanide oxidation. The effect of applied voltage, NaCl concentration and initial cyanide concentration on heavy metal removal was then evaluated for synthetic wastewater samples. Results showed that lower applied voltages and lower NaCl concentrations led to an increased removal of copper. For real process wastewater samples, only the effects of applied voltage and conductivity on metal removal were studied. Results indicated that a higher applied voltage and higher conductivity lead to increased removal of copper and zinc. The variation in results between real and synthetic wastewaters can be attributed to the higher amount and stability of metal-cyanide complexes measured in real process wastewaters. Although optimal conditions for an electrochemical system can vary depending on the water’s composition, results indicate that an applied voltage of 5V and addition of NaCl can help increase the rate of cyanide oxidation as well as metal removal. Overall, this study shows that electrochemical treatment of gold cyanidation process water can be an effective method for cyanide oxidation and simultaneous metal recovery.
    • Prioritizing circular economy strategies for photovoltaics in the energy transition

      Seetharaman, Sridhar; Barnes, Teresa M.; Mirletz, Heather M.; Eggert, Roderick G.; Landis, Amy E.; Reimanis, Ivar E. (Ivar Edmund) (Colorado School of Mines. Arthur Lakes Library, 2023)
      Photovoltaic (PV) deployment for energy transition and decarbonization necessitates an unprecedented scale-up to 75 TW globally by 2050. Multi-TW scale deployment poses significant challenges, including the large quantity of required materials. Material extraction entails environmental impacts, and fears abound that end-of-life modules will result in environmental degradation. Circular Economy (CE)—a broad system framework that maintains material value through R-actions (i.e., reduce, reuse, recycle) to promote sustainable development and improve environmental quality—is proposed to enhance PV sustainability for multi-TW deployment. However, no one has quantified the impacts of applying CE to PV in the energy transition context, and proposed solutions focus heavily on recycling, the last recourse of the ranked R-actions. This thesis quantifies and compares the virgin material demands, lifecycle wastes, energy demands, net energy, energy balance, and cumulative carbon emissions of different R-actions for PV while achieving energy transition. An open-source, system-dynamics model (PV ICE) was created to address the lack of data-based decision support tools and multi-metric quantification, enabling exploration of PV supply chains with varying degrees and types of circularity, leveraging updated reliability data and field-relevant end-of-life modes. This work also contributes open-source baselines capturing the historical and expected future crystalline silicon PV module designs, and their associated material supply chains with process-specific and market-share weightings. Analyses demonstrated that deploying long-lived modules reduces mass, energy, and carbon impacts while material circularity alone cannot minimize impacts. PV recycling can help the future decarbonization of supply chains; the magnitude of the end-of-life material will be well within our capabilities to manage responsibly, and there is time to plan proactively. Ultimately, near-term efforts to reduce the environmental impacts of PV deployment should focus on improving module lifetimes and efficiencies, and on alternate material sourcing. None of these endeavors should impede the deployment required for energy transition.
    • Integration of fiber optic data with reservoir modeling and analysis: a case study in the Wolfcamp shale

      Miskimins, Jennifer L.; Bourdon, Nicole; Fan, Yilin; Zerpa, Luis E. (Colorado School of Mines. Arthur Lakes Library, 2023)
      The ability to produce hydrocarbons from low permeability shale reservoirs has been unlocked by advancements in horizontal drilling and hydraulic fracturing stimulation techniques. Hydrocarbon production in the Delaware Basin within the Permian Basin has been increased as unconventional reservoirs have begun to be infilled with multiple horizontal wells. The differences between conventional reservoirs and unconventional shale reservoirs have necessitated changes in asset evaluation and the deployment of new technologies to analyze the production behavior of unconventional wells at the time of stimulation and throughout the production lifetime. Fiber optic technology has been utilized to characterize and visualize the production from unconventional shale reservoirs. Distributed acoustic signals (DAS) and distributed temperature signals (DTS) can be collected and analyzed through the fiber optic line installed permanently into the well. DAS/DTS can be used to evaluate flow behavior and reservoir properties during completions and over the production lifetime of the well. In this thesis, production and fiber optic data were used to analyze hydraulic fracture performance, flow behavior, and communication between wells. The data was sourced from seven horizontal wells located in the Wolfcamp shale lithology within the Delaware Basin operated by Coterra Energy. Commercial software is used to build a seven-well multistage hydraulic fracturing model and to perform rate transient analysis (RTA). Petrophysical logs, geosteering data, and petrophysical data provided on the fiber optic well were used to build the model and place the seven wellbores within the grid. The model showed that wells located in two different Wolfcamp A landing zones were communicating with each other both vertically between landing zones and within the same landing zone. The proppant and fluid pumped down into the stimulated well traveled through the reservoir into the near-wellbore region of the other wells in the development. The final model results showed that there was little uncontacted rock existing between the hydraulically fractured wellbores. The 4H well within the development had a temperature and acoustic fiber optic line permanently installed behind the casing. The DAS and DTS data from this line was used to evaluate how many of the fracturing stages are contributing to production in isolation from one another. The DAS data was taken only during the time of completions and flowback, but the DTS data was taken for two years of production. Communication between the stages in the 4H lateral was seen in the DAS/DTS data that suggested that stages were communicating with each other through failed plugs, annular channels, and through the rock and natural fractures of the formation. 45 percent of the nominal stages were shown to be in communication with other stages in the lateral. The DAS/DTS data also showed that the 4H fiber optic monitoring well was in communication with each of the five wells that were being stimulated around the same time. Hydraulic fracture order and proximity to the 4H fiber optic monitor well were determined to be causes for different types of communication and the number of communication events detected. RTA was used to evaluate reservoir properties including permeability, area of reservoir drained, and hydraulic fracture effective length. Two sets of RTA were performed. An initial RTA was performed using the nominal number of stages. After evaluating the fiber optic data from the time of completions and the long term DTS data, the RTA was re-done with the effective number of stages. The effective number of stages was derived from the DAS/DTS data showing communication events between 45 percent of stages within the 4H lateral. The RTA completed with the effective number of stages was more accurate and better matched with the known reservoir permeability gathered from the DFITs performed on the wells within the development. The permeabilities calculated from the effective stage RTA range from 0.0016 - 0.0727 md. The drainage area of the wells ranged from 110 acres to 890 acres as determined by the effective stage RTA. The effective stage RTA results on permeability better matched the Delaware Basin permeabilities for other developments. Fiber data taken during the time of completions and throughout the production life of the well was determined to be beneficial in evaluating flow behavior and reservoir properties in horizontally drilled and hydraulically fractured wells.
    • Probing pressure-induced structural dynamics in xenotime rare earth orthophosphates via in situ diffraction and spectroscopy

      Packard, Corinne E.; Sharma, Jai; Zimmerman, Jeramy D.; Brennecka, Geoffrey; Reimanis, Ivar E. (Ivar Edmund) (Colorado School of Mines. Arthur Lakes Library, 2023)
      Rare earth orthophosphate (REPO4) ceramics have attracted decades-long interest in research fields ranging from geoscience to structural composites to photonics. While these fields have historically been largely separate, their growing convergence brings added relevance to REPO4 phase transformations, the influence of stress state on transformation, and transformation detection methods. This dissertation employs in situ diamond anvil cell (DAC) synchrotron x-ray diffraction (XRD) to shed light on the activation conditions of the xenotime-monazite transformation in DyPO4 and TbPO4. First, the transformation onset pressure (Ponset) of DyPO4 (measured under hydrostatic conditions) shows Raman spectroscopy-based Ponset values are significant over-estimations, and REPO4 Ponset does not decrease linearly with RE ionic radius. Experiments also reveal the shear-sensitivity of this transformation as shear reduces Ponset significantly in TbPO4 and DyPO4 and widens the xenotime-monazite phase coexistence range in TbPO4. In addition, XRD indicates a high-pressure, post-monazite phase (likely of the scheelite structure) exists across a wider range of xenotime REPO4s than was previously known. These findings show REPO4 transformation can offer enhanced plasticity and toughening in ceramic matrix composites at lower pressures and over wider pressure ranges than expected. Long phase coexistence pressure ranges across all XRD experiments also point toward this transformation being diffusional rather than martensitic. This dissertation also shows direct-excitation photoluminescence (PL) spectroscopy can be utilized to detect the xenotime-monazite phase transformation. PL experiments yield TbPO4 transformation onset and end pressures consistent with synchrotron XRD results. In addition, PL spectra of recovered TbPO4 samples can offer insight into stress history, including history of transformation.
    • Implementation and comparative analysis of supervised machine learning methods for domain modeling and grade estimation techniques

      Dagdelen, Kadri; ASLAN, ERKAN UGUR; Miller, Hugh B.; Enders, M. Stephen (Colorado School of Mines. Arthur Lakes Library, 2023)
      In the face of dwindling economic mineral resources, this study addresses the critical need for reliable characterization of the mineral resources for improved extraction methods and safer, more profitable mining operations. Current resource modeling techniques are time-consuming, and prone to errors due to manual interpretation of detailed data leading to economic viability issues due to uncertainties associated with the estimates. Geostatistics, while a predominant method in resource modeling, depends on assumptions that may not always hold true, and common practices, such as variogram interpretations, and data filtering, can introduce errors early in the modeling process. Supervised Machine learning (ML) offers a promising alternative, capable of handling complex data sets for domain analysis and grade estimation. This research introduces novel geospatial estimation methods, validated through a case study on geological domains using Supervised Machine Learning methods. A comprehensive comparison analysis of various modeling and grade estimation methods is presented, highlighting the potential of supervised ML algorithms as an alternative to traditional geostatistical methods. However, the study also acknowledges the limitations of ML, emphasizing the importance of geographic validation and visualization, apart from statistical analysis, in ensuring methodological rigor. Recommendations for future work include enhancing ML algorithms through specific data feeding, improving sample relationships with variable orientation data, anisotropy, and anisotropy ratio, and integrating geochemical data to enhance predictability. The thesis serves as a foundational guide for future resource estimation endeavors using not only ML algorithms but also geostatistical methods, underscoring the necessity of methodological rigor and validation in both geostatistical and machine-learning applications.