The commercial development of tight oil reservoirs has reshaped the landscape of the petroleum industry in North America. However, the recovery factor (RF) of tight oil with primary depletion is very low, mostly below 10%. With a large volume of remaining oil in tight oil reservoirs, the successful execution of Improved/Enhanced Oil Recovery (IOR/EOR), even with a minor improvement of 1%, would prompt a substantial production increase. Based on various field pilots, gas injection is by far the most promising IOR/EOR technology for tight oil reservoirs. This work developed an improved compositional model and its associated simulator to understand the complex multiphase and multicomponent behaviors during gas injection into tight oil reservoirs. The model accounts for the key physics in tight oil reservoirs, including nanopore confinement, multicomponent diffusion, and their coupling with geomechanics. Firstly, a hybrid algorithm combining the Successive Substitution and Newton's method was presented to improve the phase equilibrium calculation under confinement. Secondly, a modified formulation of the Maxwell-Stefan equation was presented to better quantify the multicomponent diffusion driven by the chemical potential gradient. A physics-based improvement was then proposed for the advection-diffusion model in fractured reservoirs, where fracture, matrix, and their interface are represented by three different yet interconnected continua to better capture the transient mass exchange between fracture and matrix. Thirdly, the transport is fully coupled with geomechanics during the computation of both primary and secondary variables. The numerical technique of solving the proposed model is also detailed, with special considerations to handle the numerical issues encountered during gas injection modeling. With the more general compositional model presented above, major modifications are implemented in Fortran to update the in-house simulator MSFLOW-COM for better modeling the gas injection processes in tight oil reservoirs. Fourthly, the implemented multicomponent diffusion formulation is validated with both intraphase and interphase diffusion experimental data. For the matrix-fracture mass transfer, the implemented MINC approach with three continua can better match the results of the fine grid model than the conventional double-porosity approach. The developed simulator MSFLOW-COM is validated with a commercial compositional simulator for both primary depletion and gas injection. After validation, the simulator is used to carry out two case studies. The first case study based on the Eagle Ford play investigates the impact of nanopore confinement, geomechanics, and their coupling. The simulation shows that the nanopore confinement has a minimal impact on RF for depletion and the early cycles of gas huff-n-puff (HnP), but in the long run, it reduces RF of the light components and increases RF of the heavy components. Geomechanics is an important factor in production but not always detrimental. The second case study based on the Permian Basin Wolfcamp Shale investigates the effect of multicomponent diffusion within the fractured tight oil reservoir. The simulation reveals that multicomponent diffusion has a minor impact on the performance of depletion as oil is the dominant phase. For gas injection, the simulation neglecting diffusion will underestimate the oil RF. With the diffusion included in the model, gas HnP becomes more sensitive to the soaking time than that without diffusion. Though a longer soaking time will achieve a higher RF after considering diffusion, the incremental oil is not high enough to justify a prolonged soaking time. Simulation using the double-porosity approach leads to a similar cumulative oil RF but overestimates the RF of heavy components compared with the MINC approach with three continua. To the best of the author's knowledge, the above studies cannot be done with any commercial simulators, which neglect fundamental physics, including nanopore confinement, multicomponent diffusion, and their coupling with geomechanics. The developed model and its associated simulator in this work can help researchers better understand the complex multiphase and multicomponent behaviors in tight oil production as well as be of great use for engineers to optimize gas injection parameters in field applications.

Rainfall infiltration into soil is a key factor in both landscape development and generation of rainfall-runoff hazards like flash flooding and debris flows in recently burned areas. However, infiltration capacity is spatially and temporally variable, which makes its prediction challenging, particularly in burned environments. The extent of fire-prone areas in the western United States is growing, and locations where historically wildfires were rare are burning more frequently, highlighting a need for additional study of post-wildfire soil hydrology and associated hazards. In this work, I have compiled and re-analyzed new and existing post-wildfire Mini Disk infiltration datasets from two dozen wildfires across the western United States. This compilation contains field saturated hydraulic conductivity (KFS) estimates from different soil burn severity classes and collection times post-burn. I quantified the impact of three common methodologies for KFS estimation on the re-processed compilation, and assessed the overall fit of burned KFS estimates to normal family statistical distributions. To test if the observed variability in post-wildfire infiltration behavior can be explained by other landscape and climatological factors, I analyzed these datasets in conjunction with soil burn severity, climatological, and environmental data from each site. My results show that cumulative infiltration (CI), cumulative linearization (CL), and differentiated linearization (DL) methods for KFS estimation produce significantly different outcomes at different spatial and temporal scales, and estimates produced using these methods should not be directly compared if precision is required. Additionally, KFS estimates from burned environments do not show strong linear correlations with climatic and other environmental variables; however, the average change in KFS estimates between burn severity classes does show an inverse linear relationship with both 15-minute duration rainfall intensity for a 2-year recurrence interval storm, and pre-wildfire soil moisture. Better understanding of how post-wildfire infiltration behavior relates to regional climatic variables and burn conditions will be valuable in post-wildfire hazard prediction and modeling under the current regime of rapidly changing wildfire behavior.

Advances in high power laser technology have enabled a new generation of laser driven particle accelerator technologies. These accelerators offer unique benefits such as larger acceleration gradients or higher repetition rates over conventional radio frequency acceleration methods. In this thesis I demonstrate both analytically and numerically a novel laser driven ponderomotive acceleration scheme for accelerating electrons in free space. The technique exploits the pulse front tilt (PFT) of simultaneously spatially and temporally focused (SSTF) laser pulses to reduce the pulse’s interaction speed with the electrons to below the vacuum speed of light. The reduction in the pulse front velocity allows electrons to be captured and accelerated sideways, like snow on a snowplow, by the ponderomotive force of the intense laser pulse. The analytic scaling laws of tilted snowplow ponderomotive acceleration are derived, and single particle simulations are performed to verify the basic scheme. In addition, a model of SSTF pulse propagation is implemented in the particle-in-cell (PIC) code OSIRIS 4.0 and used to study collective dynamics of the acceleration scheme. To study the dynamic evolution of the SSTF pulse, a novel version of the dispersion scan pulse characterization technique is demonstrated which can measure the temporal profile of the SSTF pulse at any longitudinal position in the focus and characterizes the angular chirp. This method is combined with a novel, improved phase retrieval algorithm for dispersion scan which uniquely determines the correct sign of the retrieved field through the application of Newton’s method. Additional work demonstrates a nonlinear optical process where photon spin can be converted to photon orbital angular momentum through second harmonic generation in underdense plasmas. This helps illuminate the fundamental nature of the angular momentum of light and its interaction with ordinary matter.

The temperature on earth is rising. Studies show that the average surface temperature is already 1°C higher than in pre-industrial times. This rise in temperature is directly linked to anthropogenic carbon emissions and will only continue to rise if immediate action is not taken. Work to improve sustainability in our society has already begun, with vast improvements in solar, wind, geothermal, and other forms of sustainable energy production being made every day. Fossil fuel dependency is pumping carbon dioxide into our atmosphere at unsustainable rates, and cyanobacteria present a feasible means to combat emissions and close the carbon loop for a more sustainable future. Cyanobacteria are prokaryotic, photosynthetic microorganisms with the capability to produce a wide range of chemicals, from biofuels to plastics to sugar to rubber, all while utilizing minimal resources. Only sunlight, trace minerals, unarable land, and sub-optimal water such as ocean water are needed for growth and production of valuable specialty and commodity chemicals. With a higher photosynthetic eciency and genetic tractability than plants and no competition for arable land or fresh water, cyanobacteria have the potential to be pivotal in the ght against climate change. In this thesis, I characterize the central metabolism of a biofuel producing strain of cyanobacteria to gain a better understanding of how to manipulate cyanobacterial metabolism for increased production of not only biofuels but a range of valuable products. I probe pathways of primary and secondary metabolism using metabolic engineering techniques in an eort to glean useful information and help demystify the complex metabolic network of these complex organisms. Additionally I improve and validate existing tools needed to accelerate the design-build-test-learn cycle and establish cyanobacteria as a commercially viable sustainable producer of valuable products.

This thesis discusses the first Spatial Frequency Modulation Imaging (SPIFI) system capable of collecting data at video rate speeds. In the brief history of SPIFI, systems have been limited in imaging dynamic samples due to line imaging rates in the range of 20 to 30 hertz. The creation of a Video Rate SPIFI (V-SPIFI) system, utilizing a stationary reflective rectangular modulation plane and an air-bearing polygonal scan mirror, allows for dynamic sample imaging with concurrent data availability. The resulting V-SPIFI system is capable of capturing line images over 240 times faster than previous SPIFI systems. By implementing a prototype electronic optical control subsystem, the V-SPIFI system is also capable of automatically scanning a sample and rendering 25 first and second harmonic order images in approximately five seconds. To provide context, a brief history of modern microscopy techniques and limitations is included. Next, using the theory of SPIFI imaging, the modeling and construction of the six interconnected optical and electronic subsystems required for the V-SPIFI system are detailed. Resulting first and second order harmonic images are presented, including pixel size and estimated first order image resolution. A visual verification of image accuracy is also provided. Finally, concepts for future V-SPIFI systems are discussed, as well as possible applications of the V-SPIFI system.

Fractured rock is ubiquitous throughout the Earth's surface and near-surface environments. Fractures act as preferential flow pathways through an otherwise relatively impermeable medium, delivering reactive fluids and transporting solute through the subsurface. The ubiquity of fractures in the natural environment and the important role they play in rapid delivery of fluid to the subsurface makes flow, transport, and reaction in fractures an important field of study. This study uses numerical simulations to better understand how heterogeneity associated with fractures impacts mineral dissolution rates. In addition, the rate of mineral dissolution impacts the extent of reaction front propagation, which has important implications for anthropogenic use of fractured rocks as repositories for geologic storage of CO2 or nuclear waste. In 2 and 3 dimensional models, the rate of mineral dissolution is impacted more by the fluid flow rate than the structure of the subsurface fracture pattern, additionally, the reaction over geologic timescales becomes transport-limited. The findings from the numerical studies are then applied to a field site with unique subsurface structures across a north and south-facing hillslope in the Gordon Gulch catchment of the Boulder Creek Critical Zone Observatory. The presence of groundwater wells across the catchment allows us to determine that water draining the fractured bedrock is saturated with respect to the major minerals and therefore reaction is transport-limited at the field scale. This study shows that mineral dissolution in heterogeneous domains leads to depletion of minerals in fast flowpaths over relatively short geologic timescales, but reaction over long geologic timescales occurs in protected regions, or matrix, that are transport-limited.

In this work, the compositional families Sr1-xCexMnO3−δ (SCMX, X = 100x,x= 0.10, 0.20, & 0.30) and CexSr2-xMnO4−δ (CSMX, X=100x, x= 0.10, 0.20, & 0.30) are studied to determine the effects of perovskite structure and cerium content on the thermal reduction thermodynamics and the resulting impact on solar thermochemical hydrogen-production (STCH). Relying on thermogravimetric results from oxygen nonstoichiometry experiments, fits for various thermodynamic quantities, including defect-reaction specific enthalpy and entropy, ∆H◦ and ∆S◦, as well as theδ-dependent standard partial molar enthalpy and entropy of oxygen, ∆ ̄h◦O and ∆ ̄s◦O, are produced as a function of composition within these two perovskite families using a thermodynamic model developed herein. The results of this thermodynamic study in the context of structure and cerium dopant level are discussed, and several improvements to the model are proposed and explored. Experimental hydrogen production results show that the SCM family produces slightly larger amounts of hydrogen per mole of oxide compared to the CSM family under similar reduction and oxidation temperature conditions, however a direct correlation between structure, cerium content and water-splitting capacity could not be discerned. Lastly, compositions of Ca1-xCexMnO3−δ(CCMX, X = 100x, x= 0, 0.10 & 0.20) are explored for the composition’s predicted ability to reduce on both the A- and B-sites of the simple perovskite oxide material, however low melting temperatures prevent further study of this compositional family for STCH purposes.

Electrical and spin transport measurements at cryogenic temperatures have powered new arenas of research and applications. However, exploration into thermal effects at cryogenic temperatures has only just begun. Recent thermal transport measurements at low temperatures have led to interesting novel physics in the fields of quantized heat flows, quantum thermodynamics, thermal Josephson effects, quantum heat engines, and thermoelectric materials. In particular, superconductor-ferromagnetic (S-F) systems have recently been proposed as effective thermoelectric devices. While conventional superconductors are known to be poor thermoelectric materials, the combined effects of spin splitting and spin filtering provided by an external magnetic field and magnetic material are predicted to create an asymmetry in the superconducting density of states and generate thermoelectric effects. These S-F systems have been predicted to have a thermoelectric figure of merit (zT) of 1.8, far exceeding any other thermoelectric materials at cryogenic temperatures. If these predictions hold true, S-F thermoelectrics could have applications in nanoscale cooling and as radiation or single photon detectors. In this thesis, we have directly measured the Seebeck voltage in S-F structures down to 8 mK and developed the hardware and techniques necessary to make such a measurement at cryogenic temperatures. First, we review the background and theoretical underpinnings which inform and motivate the study of S-F systems as thermoelectric materials. Second, we report our development of methods for the electrodeposition of superconductor and ferromagnetic nanowires, including the first fabrication of niobium nanowires via electrodeposition. Third, as methods of thermal measurements at cryogenic temperatures are not well established, we have developed an experimental platform for low dimensional temperature measurements. Our experimental advances in this area include the development of an on-chip cryogenic thermometer that is sensitive down to 8 mK and can be placed on the chip with 100s of nm precision in a lithography free process. We also have quantified local, on-chip heating using AC and DC power as a function of distance, power, frequency, and sample configurations. Finally, we directly measure the Seebeck coefficient of Al, Ni, and an Al-Ni junction below 1 K.

Implementation of advanced nuclear fuel cycles is critical to a sustainable future for nuclear energy production. Closed nuclear fuel cycles proposing to transmute long-lived minor actinide elements, such as americium, into shorter-lived nuclides using advanced reactors hinge on the separation of americium from the lanthanides. Though many separation schemes have been proposed, the physicochemical properties of the trivalent actinides and lanthanides pose a challenge to refining their efficiency for industrial application. The ALSEP (Actinide-Lanthanide SEParation) process is a relatively new separations protocol whereby the An3+ and Ln3+ cations are (1) co-extracted from 3-4 M nitric acid into a mixture of the extractants HEH[EHP] (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) and TEHDGA (N,N,N’,N’-tetra(2-ethylhexyl)diglycolamide) in n-dodecane, (2) scrubbed of excess nitric acid with a buffered aqueous solution, and (3) selectively stripped of americium by a buffered aqueous phase containing polyaminopolycarboxylate ligand, commonly DTPA (diethylenetriaminepentaacetic acid) or HEDTA (N-(2-hydroxyethyl)ethylenediamine-N,N’,N’-triacetic acid). Though ALSEP has demonstrated many advantages over its predecessors, the fundamental chemistry of the strip step remains a critical bottleneck to the process’ implementation. The body of work available for understanding equilibrium complexation and the kinetic barriers in ALSEP is limited. Accurate interpretation of kinetic data begins with defining the speciation of the metals, ligands, and extractants in each phase and step. The equilibrium characterization work presented here is the first to provide a definitive stoichiometry for the metal extracting complex in ALSEP. In addition, changes in complexation were probed in both buffered and un-buffered systems, over a broad range of process relevant acidities. A speciation model of the metal-extractant complexes that describes the speciation transitions from start to finish are also defined for the first time. Finally, the kinetics of the strip step was investigated using buffered and self-buffered EDTA (ethylenediaminetetraacetic acid) solutions. Rate laws were attained, and reactions contributing to the rate-limiting mechanism were suggested. Additionally, EDTA was replaced with the self-buffering picolinic acid-substituted derivative EDTA-Mpic (N-2-methylpicolinate-ethylenediamine-N,N’,N’-triacetic acid), to access the stripping kinetics under lower pH conditions. The evidence so far suggests that picolinate functionalization improves mass transfer rates through the solubility of the picolinic acid substituted arm and provides effective self-buffering for similar kinetic benefits to that seen in the standard ALSEP system.

Since the mid 20th century, energy consumption has been the main driver of human-induced climate change, rapidly warming the planet’s atmosphere, oceans, and land. These trends have led to growing efforts to develop more sustainable feedstocks to meet increasing energy demands. Guar (Cyamopsis tetragonoloba) and guayule (Parthenium argentatum) are potential feedstocks for renewable fuels; these crops have highly valuable co-products that can enhance their economic viability. Guar and guayule are draught tolerant crops that can be cultivated in the Southwest US. Guar bagasse can be utilized to produce bioenergy, and its co-products include guar gum, a highly valuable chemical used in the food industry as an emulsifier and in the hydraulic fracturing industry as a friction reducer. Guayule bagasse can also be utilized to produce bioenergy, and its valuable co-products include natural rubber and resin, the latter of which can be used to make adhesives, coatings, antifungal agents, and fuels. To ensure holistic sustainability of these emerging agricultural feedstocks, an array of sustainability tools must be utilized in tandem. This thesis quantifies the three pillars of sustainability - environmental, economic, and social – for guar and guayule and assesses their potential to be integrated into the southwestern bio-economy. Life cycle analysis (LCA) was used to quantify the environmental impacts of guar and guayule, highlighting that irrigation is the main driver of agricultural impacts and thus provides the biggest opportunity for improved agricultural sustainability. Techno-economic analysis (TEA) quantifies the economic impact of guayule rubber production showing irrigation as the main agricultural contributor of economic impacts, while the largest processing contributor is capital/loans. This research is unique in its LCA and TEA approach, where data was collected from field trials and interviews of farmers and researchers were utilized to determine data quality and likelihood. This process produces more robust LCA and TEA results that are more representative of commercial farming practices. Existing social assessment tools were reviewed to determine the most appropriate approach for evaluating social sustainability. Ultimately, social sustainability was assessed by conducting focus groups of guar and guayule farmers and experts to identify social challenges and opportunities. This research aids in providing a clear path for the holistic sustainable development of a bio-economy in the Southwest US for guar and guayule.