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Electro-Chemo-Mechanics of Several Pure Metal Anodes for Rechargeable Batteries
No full textBy enabling constant access to electronic devices and seamless communication capabilities, energy storage devices have greatly improved our lives. With advances in technology over time, the demand for larger capacity and longer lifetime energy storage devices continues to increase. Still, technological hurdles, such as safety issues, kinetic limitations, and material degradation over time, remain that must be addressed to enable the next generation of high-capacity batteries. While battery research primarily has focused on improvements in electrochemistry, higher capacity technologies have necessitated a shift to the focus towards more multidisciplinary approaches in research.
This dissertation explores battery materials from a mechanical and coupled electro-chemo-mechanical perspective by evaluating various materials��� intrinsic mechanical properties and analyzing their mechanical behaviors during electrochemical cycling. Fracture behavior of sodium was investigated, highlighting its extreme ductility and flaw-insensitivity at room temperature. Furthermore, calcium was mechanically assessed at various length scales, which unveiled calcium���s relatively limited ���indentation size effects��� as compared to counterparts of Li and Na metal, likely due to its relatively high melting point and relatively low dislocation spacing. Additionally, various lithiated compositions and phases of Li���Mg alloy anode were mechanically evaluated via nanoindentation. XRD patterns on post-mortem lithiated Mg samples revealed that Li���Mg alloy anodes undergo a single-phase transformation electrochemically, from the Mg-rich �� phase (HCP) to Li-rich �� phase (BCC). Furthermore, the nanoindentation hardness and elastic modulus of Li���Mg was found to significantly decrease with increasing lithium concentration. This dissertation also investigates the mechanical behavior of pure lithium metal anodes under various electrochemical conditions. These tests uncovered a marked current-dependent mechanical stress response of lithium. Keeping in mind that the processes of electrodeposition of lithium and the growth of Li dendrites, while distinct, share similar underlying mechanisms, these measurements provide important insight into understanding the growth of Li dendrites.
Overall, this dissertation investigates the mechanics of various battery anode materials that exhibit an intimate interplay between mechanics and electrochemistry; their overall performance in practice is thus highly dependent on their mechanical behavior. As such, this dissertation provides general insight into understanding energy storage systems in terms of the intricate interactions between mechanics and electrochemistry
Effect of Select Interpretive Story-Telling Techniques on Narrative Transportation and Engagement Among Youth Educational Travelers
No full textThis study examined the effect of select story-telling strategies interpreters use on engagement and narrative transportation of youth educational travelers. Engagement is the subjective state of motivation that occurs when one���s attention is focused on a story being told. Narrative transportation can also occur during story experiences. The traveler (i.e., reader, listener, spectator) is carried, via imagination, to the destination of the story; a different time, place, and set of circumstances. Heritage interpreters and tour guides for youth educational travel experiences use a variety of techniques to invite narrative transportation and engagement, but the effects of such techniques have not been studied experimentally. Four strategies were evaluated: use of visual aids, verisimilitude, use of music, and self-relevance elicitation. One hundred forty-four experience observations from 18 4-H youth enrolled in an educational travel experience to Spain were analyzed. Youth visited different sites in Barcelona and Madrid. During the daily reflection period, the researcher told a fictional story set in the site or sites visited that day. The four techniques were systematically varied across eight different stories to determine the relative effect of each technique on narrative transportation and engagement. After listening to each story, youth completed an electronic questionnaire measuring narrative transportation, engagement, and down-stream outcomes (perceived value of time spent and proclivity to recommend). Verisimilitude and self-relevance increased engagement and engagement increased narrative transportation. The effects of music and visual aids were not significant. Narrative transportation increased with increases in engagement, and perceived value of time spent listening to the story and proclivity to recommend were positively correlated with narrative transportation
Improving the SPEE Monograph 3 Approach through MLR-Normalization
No full textIn 2008, as part of a modernization effort, the Securities and Exchange Commission (SEC) adopted rules restricting undeveloped reserves to acreage directly offsetting existing wells unless reliable technology could justify greater distances. This rule significantly limited the amount of proved undeveloped (PUD) reserves that could be disclosed in unconventional plays, which require more wells to fully develop than their conventional counterparts. Recognizing the industry's need, the Society of Petroleum Evaluation Engineers (SPEE) published its third monograph in 2010.
The SPEE Monograph 3, while innovative, limited its calculations to estimated ultimate recovery (EUR) normalized by completed lateral length (CLL). It otherwise overlooks other operator-controlled variables, such as completion design, location and well depth, which are shown to have a significant impact on performance.
In the following thesis, I augment the SPEE Monograph 3 approach with multiple linear regression (MLR) models using certain operator-controlled variables from publicly available sources. I generate an equation to explain additional variability in performance and normalize EURs. Finally, I follow the SPEE Monograph 3 recommendations for estimating proved areas and volumes, comparing the results to CLL-normalization alone.
In the Woodford case study, my proposed workflow was shown to reduce minimum analogs required for the initial establishment of reliable technology by 27%, resulting in the booking of PUDs beyond direct offsets 18 months sooner. Additionally, the use of MLR-normalization resulted in proved areas up to 15% larger and proved volumes up to 31% larger than CLL-normalization.
Modern software and data availability make MLR models achievable for operators of all sizes. My work utilized RStudio, a free programming software with many statistical packages, and Enverus, an online subscription service to oil and gas data. With some effort, MLR modeling is programmable, making it easy to integrate into existing PUD workflows
An Evaluation of Alternatives for Updating Base Acres in the 2024 Farm Bill
No full textGiven that the income-support provisions in the farm bill have been decoupled from production for more than two decades, base acres are no longer reflective of planted acres in the United States. Three alternatives are currently being discussed to better align base acres with current plantings in the next farm bill: 1) a reallocation of bases to current plantings, 2) a forced update to current plantings, and 3) a rolling average of the plantings from the previous two years. There undoubtedly will be winners and losers across individual operations, crops, and regions. Knowing who will be impacted would enable Congress to make more informed decisions regarding base updates. To comprehensively evaluate the alternatives, this study undertook a farm-level and national analysis.
The farm-level analysis was implemented by collecting data from four representative farms maintained by the Agricultural and Food Policy Center at Texas A&M University. For each farm, base acres were calculated for the three alternatives, and stochastic simulation was used to determine a five-year forecast of average government payments, ending cash, and ending real net worth. The national analysis was conducted by collecting public data from the Department of Agriculture���s Farm Service Agency for nine covered commodities and calculating new base acres per county to determine absolute gains and losses. The absolute change per crop per county was totaled to determine the deviations between the current baseline and each scenario being analyzed.
The results from the farm-level and national analysis indicate a wide variety of impacts on individual farms, crops, and regions. While maintaining current base acres might be the optimal solution for one location or commodity, it is apparent that the same scenario would be less preferred by others. One universal option (e.g., to reallocate base acres) might not be the best solution; in fact, allowing producers to choose amongst several options might be the best route for baseline modification in the next farm bill, recognizing that approach will also cost the most
Lip Position Preferences as They Relate to Convexity and Divergence
No full textIntroduction: The aim of the present study was to assess lip position preferences as they relate to convexity and divergence. Of secondary interest were how sex, ethnicity, and age influenced these preferences.
Methods: A sample of 1000 internet users were asked to rank the relative attractiveness of a series of modified 3D facial profiles with differing lip projections. One Caucasian male served as the model, and the model's facial scan underwent mandibular augmentation in the sagittal and vertical dimensions resulting in nine distinct facial profiles. Following these augmentations, the lips were adjusted anteriorly and posteriorly in 1.5 mm increments from baseline.
Results: Each of the nine facial profiles experienced significant within-group differences in preferred lip position. Females preferred more protrusive lips in all profiles than males. African Americans preferred more retrusive lips for nearly all profiles than Caucasians and Hispanics. Younger generations tolerated more retrusive lip positions compared with older generations for nearly all profiles.
Conclusions: Preferred lip positions are a function of convexity as opposed to divergence; facial types with vertical imbalances followed similar trends to those seen in other facial types with similar convexity. Sex, ethnicity, and age-related preferences persisted despite most facial imbalances
Shock-Driven Multiphase Mixing Physics in High-Speed Flows
No full textThe Shock-Driven Multiphase Instability (SDMI) occurs when a multiphase (particle-gas) medium is instantaneously accelerated by the passage of a shockwave. It has applications in detonation-driven propulsion engines, explosive dispersal of particles, hydrometeor impacts in hypersonic flight, and astrophysics events. The SDMI involves several phenomena that occur concurrently across overlapping length and time scales, from the mesoscales (cloud-scale) to the microscale (particle-scale). At the larger scales, the problem involves turbulent mixing due to acceleration across pressure and density gradients, like the classic Richtmyer-Meshkov Instability; however, including effects of larger particle or droplet sizes results in longer equilibration times and decreased mixing. At the microscale, in the case of liquid droplets, particle-scale mixing occurs due to droplet breakup and evaporation at a high Weber number. The concurrent phenomena under these conditions are complex and poorly understood, warranting research in numerous physical systems.
Considering this, I will present the findings derived from recent experiments that quantify the multiphysics aspects of the SDMI. I will dive into the impact of the particle velocity relaxation time on hydrodynamic evolution to enhance the accuracy mixing predictions from circulation deposition models. Additionally, I will explore particle-scale mixing, encompassing droplet breakup and vaporization, in quasi-1D experiments to gain a deeper understanding of their influence on hydrodynamic mixing. Moreover, I will explore the effects of high particle evaporation rates on multiphase hydrodynamic mixing. Ultimately, this work intends to develop models that accurately predict cloud-mixing time and length scales, as well as the dynamics of particle-scale mixing
Probing Membrane Protein-Ligand Interactions Using Native Mass Spectrometry
No full textThe cell membrane, essential for cellular structure and function, is composed largely of membrane proteins and lipids. While transmembrane proteins are known for their critical roles in various physiological processes such as maintaining cell resting potential and facilitating molecule transport, the specific interactions between these proteins and different lipid moieties are not fully understood. In this study, we employed native mass spectrometry as a primary tool to unravel these interactions, capitalizing on its unique ability to preserve non-covalent interactions in biomacromolecules.
Our investigation comprised two distinct approaches: single ligand screening and multi-omic screening. Through single ligand screening, we identified specific lipid moieties that bind to the mammalian two-pore domain potassium channel TRAAK. This approach not only pinpointed the preferred lipids but also revealed a dose-response relationship with TRAAK potassium efflux in functional assays. On the other hand, our multi-omic analysis yielded significant findings. It corroborated the unique allosteric modulation observed between cardiolipin and phosphatidylethanolamine in their interaction with the E. coli ammonium channel AmtB, aligning with previous research. Additionally, this approach led to the discovery of a complex allosteric modulation involving TRAAK, phosphatidylserine, and cupric ions. Impressively, these interactions were maintained when ejected from proteoliposomes, bridging our functional assays, and validating our methodologies.
Moreover, our research broke new ground with the synthesis of novel charge-reducing molecules. This advancement has significantly enhanced the study of less stable membrane proteins, paving the way for more comprehensive exploration of membrane protein-lipid interactions. Overall, our findings contribute substantially to the understanding of cellular membrane dynamics and functionality, marking a significant stride in the field of cellular biology
Investigation on Wellbore Cement Integrity During Carbon Capture and Storage (CCS) and Underground Hydrogen Storage (UHS)
No full textThe interactions between hydrogen and carbon dioxide (CO2) with wellbore cement are not fully understood, raising concerns about potential degradation and failure of cement barriers during carbon capture and storage (CCS) and underground hydrogen storage (UHS). This study offers an in-depth analysis of the geochemical, petrophysical, and geo-mechanical properties of cement before and after exposure to hydrogen and CO2. In this study, the cement samples were saturated in 30,000 ppm brine and exposed to the different gases at a pressure of 500 psi and temperature of 50 C for 30 days. In the hydrogen experiment, a notable chemical alteration within the cement matrix was observed, marked by a 50% increase in brownmillerite and a 70% decrease in ettringite. Computed tomography (CT) scans revealed both diminished and clogged pores, along with areas of denser material precipitation. Correspondingly, porosity and permeability measurements showed decreases of 2% and 40%, respectively, while compressive strength and Young's modulus experienced increases of 35% and 6%. The exposure of the cement to CO2 showed significant mineralogical changes, with calcite appearing, constituting 8.7% of the mineral composition, and a complete depletion of alite, signaling extensive carbonation. CT scans highlighted a substantial reduction in pore size and sealed fractures due to calcite precipitation, dramatically affecting porosity and permeability, which decreased by 98% and 87%, respectively. Moreover, the mechanical properties saw remarkable improvements, with compressive strength and Young's modulus increasing by 126% and 161%.
This research is a first of its kind, providing a comprehensive characterization of cement samples before and after exposure to hydrogen, and comparing the results with that of CO2 exposure at the same experimental conditions. The methodological and detailed experimental and analysis approach provided a clear understanding of the interrelationship between the petrophysical, geochemical, and geomechanical impact of exposing the fluids to cement. The findings indicate that in the absence of cyclic and confining stresses, hydrogen and CO2 will not degrade the strength of the cement but, in some cases, could offer healing of fractures and microcannulas if present. The reduction in porosity and permeability of the samples suggests that losses will be reduced when the cement is exposed to hydrogen or CO2
Uncertainty-Aware Data-Driven Approaches for Modelling Sparse Agricultural Datasets to Sustain a Society
No full textThe objective of my dissertation is to tackle the issue of sparse datasets in case of agricultural domain to design data-driven approaches that can be used to make Decision Support Systems (DSS) for optimal growth of plants, thereby reducing the cost of labor as well as improving the overall food security and environmental sustainability. In order to achieve this, my research is structured into three primary components. Firstly, it focuses on utilizing Machine Learning (ML) models and data-driven approaches to optimize nutrients in hydroponic and aquaponic environments, enhancing the growth of fish and plants within a unified system using two distinct methodologies. This addresses the inherent sparsity in agricultural datasets. Secondly, the thesis delves into the development of forecasting models for in-season prediction of canopy features in cotton crops. This predictive capability enables timely management decisions to maximize crop yield. The third objective involves the creation of data-driven approaches to model growth stages and nutrient uptake of soybeans cultivated in hydroponic environments, spanning from seeding to maturation
Direct Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol, Investigating the Effect of Reaction Conditions and Dehydrating Agents
No full textDimethyl carbonate (DMC) is attracting attention lately because of its environmentally friendly characteristics as it is known to be a non-toxic, non-corrosive, and biodegradable material. DMC direct synthesis presents an environmentally friendly approach as it utilizes carbon dioxide (CO2) and does not use hazardous materials as in other processes. Despite its potential for CO2 fixation, several challenges restrict methanol conversion to DMC to around 1%, primarily due to water formation favoring DMC hydrolysis. Therefore, solution such as the use of dehydrating agents and a reactive distillation have been proposed. Different dehydrating agents have been experimentally studied such as zeolite 3A, zeolite 4A, and ZSM-5. Before assessing dehydrating agents, various experiments were conducted to optimize reaction conditions, revealing that the highest DMC yield occurs at 110��C, 30 bar pressure, 200 mg catalyst dosage, and a 2-hour run duration. Tested dehydrating agents slightly increased DMC % yield; however, they failed to shift the equilibrium adequately. Consequently, reactive distillation is seen as a promising alternative, necessitating a kinetic model for accurate prediction. A low-pressure kinetic model was developed within this work, showing good agreement with experimental data (MAPE: 17%). After that, a CO2Fix metric was used to study the potential of the direct synthesis method for CO2 fixation. Based on the model, it was concluded that 2-CP exhibits the highest CO2Fix potential with a 3.68 CO2Fix. Moreover, it was determined that compounds with 6-membered nitrogen heteroaromatic ring such as benzonitrile, acetonitrile, and shows higher CO2Fix potential compared to other dehydrating agents