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Influence of Rock Types on Porosity-Permeability Relations in Clastic and Carbonate Reservoirs with Application to CO2 Storage Site Characterization
No full textAccurate site characterization is essential for evaluating geological carbon dioxide storage potential. Geoscientists can model and monitor the behavior of injected carbon dioxide and rock interactions with knowledge of spatial variation of porosity and permeability. This thesis aims to estimate and understand permeability in carbonate and clastic reservoirs with geological analysis and acoustic well log data.
Jennings and Lucia (2003) model is used to calculate rock fabric numbers (����) in a carbonate reservoir in the Michigan Basin. By integrating information about the cored sections, three distinct classes were identified from rock fabric numbers. With Sun model (2004), a shear-frame flexibility factor (������ ) is calculated from acoustic properties and is used to relate permeability to rock pore structures. The shear-frame flexibility factor (������ ) is related to rock fabric numbers (����) through a linear transformation. The relations between shear-frame flexibility factor and rock fabric numbers will be very useful to estimate permeability from acoustic log and 3D seismic data, which will help predict CO2 pathways in potential CO2 storage sites.
This research also indicates that with sonic logs, we can calculate volume of shale in clastic reservoirs and relate to permeability. Permeability is controlled more by clay content in higher porosity zones. Higher volume of shale values indicates lower permeability values and that mechanical strength and pore structure play a greater role when constraining permeability values. Volume of shale can be related to elastic properties with Sun model (2004). The shear-frame flexibility factor can help constrain ranges of permeability in clastic reservoirs more accurately when porosity is at least 20%.
In addition, a fluid substitution model can be produced with Gassmann���s equations (1951). The impact of different fluid saturation changes is caused by CO2 injection on elastic properties and can be detected from synthetic seismic modeling and related to post-stack inversion results.
The theoretical results of this thesis are valuable for site characterization and locating potential CO2 storage, especially with the use of these rock physics models. With these results, geoscientists can use these methods to better comprehend the behavior of injected CO2 and rock interactions in the reservoir
Using Stimuli-Responsive Material for the Design and Fabrication of Artificial Muscles
No full textStimuli-responsive materials that change shape (i.e., elongate, contract, and/or twist) when exposed to an appropriate stimulus are promising candidates to replace traditional machines in biomedical devices. This dissertation explores the innovative use of stimuli-responsive materials in addressing the challenges of treating stress urinary incontinence (SUI), a condition that affects nearly 50% of women during their lifetime. Current treatments for SUI are associated with complications leading to undesirable outcomes such as postoperative voiding dysfunction. The research, divided into four key chapters, focuses on the development and application of artificial muscle devices based on two distinct stimuli-responsive materials ��� Liquid Crystal Elastomers (LCEs) and Magnetoactive Elastomers (MAEs) for the potential treatment of SUI.
In Chapter I, the dissertation commences with a comprehensive introduction to stimuli-responsive materials, elucidating their pivotal role in the design and fabrication of artificial muscles. Emphasizing the versatility of two materials (LCEs and MAEs), the chapter provides a foundation for their application in the subsequent chapters. Chapter II delves into the pathophysiology of SUI, providing a thorough overview of the condition, including its causes, prevalence, and impact. This section establishes the contextual framework for the subsequent exploration of the subsequent development of LCE and MAE-based devices for urethral support. We also provide relevant information that must be considered when designing in vitro models of the urinary tract and selecting appropriate animal models to evaluate devices. Chapter III focuses on the design, fabrication, and in vitro and in vivo evaluation of a dynamic urethral support device based on LCEs. In Chapter IV, I extend the exploration to MAEs and investigate their integration into a dynamic urethral support device. MAE-based devices were fabricated, characterized, and then evaluated using a simple in vitro urinary system simulating the effects of stress or cough.
Collectively, this dissertation contributes to the interdisciplinary field of biomedical engineering by integrating stimuli-responsive materials with innovative solutions for SUI. Investigating the potential of LCEs and MAEs in providing adaptive and customizable support, this dissertation presents a novel approach to addressing SUI through advanced materials. The findings presented herein pave the way for further advancements in the design and fabrication of artificial muscles, offering hope for improved therapeutic interventions for complex healthcare challenges
The Genetic Basis of Seasonal Migration and Its Role in Reproductive Isolation
No full textSeasonal migration has been suggested to play a role in speciation through environmentally induced selection against hybrids. Many migratory divides occur between groups that take different migratory routes. For example, the songbird Swainson���s thrush forms a migratory divide in western North America. This species includes two subspecies; coastal thrushes migrate along the west coast of North America while inland thrushes migrate east of the Rocky Mountains, through central North America to South America. These routes are largely genetically determined and involve navigation around geographic barriers. Hybrids in the divide have been shown to take intermediate routes that lead them through these barriers, potentially reducing their fitness. I used this system, spatial modeling, state-of-the-art tracking and genomic techniques to test the role migratory behavior plays in speciation.
First, I used spatial modeling and habitat preferences of birds on migration to show that hybrids taking intermediate routes have less access to highly suitable habitats and encounter more resistance on their routes compared to parental forms. These findings suggest that intermediate routes are inferior to routes taken by parental birds and there could be selection against hybrids contributing to speciation. Second, I individually tracked over 500 adult and juvenile Swainson���s thrushes from the center of the hybrid zone, obtaining detailed data on several migratory traits (e.g., orientation, timing, and wing morphology). Genomic mapping showed that most migratory traits are highly heritable and genetically correlated. I also mapped these traits to specific genomic regions, gaining insight into how these traits may be co-regulated and generating a list of candidate loci that are associated with these traits. Third, I used genomic data and analyses of viability selection to identify signatures of selection along the genome. I connected these regions with the genes associated with migration and showed that these loci are under selection. Combined, results from this dissertation provide one of the most comprehensive tests of seasonal migration as a driver of environmentally induced selection against hybrids in a free-living population that has ever been conducted. My results also provide insight into additional fields, including behavioral genetics and conservation biology
Spinal Plasticity: Using Spinal Learning to Inform Maladaptive and Adaptive Effects of Nociceptive Input After Spinal Cord Injury
No full textThe traditional dogma of the spinal cord as a rigid conduit of information has been challenged in recent years. Evidence demonstrates that circuitry within the spinal cord can undergo adaptive and maladaptive plasticity particularly after spinal cord injury. Our work has focused on instrumental learning in the spinal cord along with the impact of nociceptive input after spinal cord injury. In this dissertation I explored how spinal cord injury affects plasticity. This work places particular emphasis on the impact of nociceptive input and factors that allow peripheral input to drive adaptive rather than maladaptive plasticity.
This dissertation explored spinal plasticity after injury in a complete thoracic (T2) transection in order to clarify the properties of the spinal cord itself. The first series of experiments show that the consequences of training vary with duration. These experiments also revealed two unexpected findings that motivated the following two chapters.
The second series identified a previously unknown effect of exposure to controllable
stimulation. An extended exposure to controllable stimulation altered how later stimulation is
interpreted, causing it to be read as adaptive (controllable) regardless of how it was presented.
This series also identified the anatomical locus of this shift and began to clarify its mechanistic
underpinnings.
The next series of experiments clarified the impact of proprioceptive signaling on the effects of uncontrollable noxious input. These experiments found that limb position modulates how nociceptive stimulation affects spinal cord plasticity. This series revealed that noxious stimulation only impairs plastic potential when applied while the hind limbs are extended.
The final set of experiments explored the role of ionic plasticity in spinal plasticity after injury. These experiments focused on the importance of the release of the GABAergic break on adaptive plasticity. They also identified pharmacological manipulations that can be used to manipulate ionic plasticity and, as a result, spinal plasticity. This suggests the potential of harnessing ionic plasticity to drive adaptive over maladaptive change.
Collectively, these experiments highlight the potential of harnessing plasticity after spinal cord injury for good. The studies show how the consequences of nociceptive stimulation vary with duration, order of presentation, limb position, and changes in GABA-dependent inhibition
A Massively Parallelizable Surrogate-Based Modeling Framework for Nonlinear Static Aeroelasticity and Structural Design
No full textAnalyzing the multiphysical coupling between a deformable structural body and the forces
imposed on that body from a surrounding fluid can be a challenging and computationally expensive
task, especially when the structure and/or fluid exhibit highly nonlinear behavior. Consequently,
preliminary design of aerostructures often relies upon simplified mathematical models
limited to linear fluid and structural regimes to enable tractable exploration within a design space
predominantly defined by convention and engineering expertise. While this has historically proven
reliable, such design practices are inadequate for developing next-generation aerial systems requiring novel structural solutions for in situ geometric reconfigurations that enable continuous
optimization of aerodynamic performance, enhanced control authority, and expansion of operational
capacity. Accordingly, there exists a need for novel reduced-order multidisciplinary analysis
techniques agnostic to the underlying complexities of the physical problem that make efficient
use of high-fidelity computational models to resolve the exchange of field information between
disparate physics subdomains. This work explores a highly parallelizable non-intrusive reduced-order
modeling technique that seeks to construct an aeroelastic surrogate model approximating the
function composition of the high-fidelity structural model and fluid model in terms of shape parameters characterizing a reduced geometric description of the deformed interface boundary between physics domains. The proposed methodology removes the need for a reduced-order representation of the traction field acting on the structure, eliminates computationally expensive fluid evaluations during structural design procedures, and requires no explicit communication between independent fluid and structural models. Furthermore, while this data-driven modeling approach is highly enabling for parametric multi-objective structural design optimization during preliminary design
stages, identifying structural design variables requires foreknowledge of the structural topology.
This work applies many of the same principles to develop a novel reduced-order aeroelastic topology
optimization framework that supplements conceptual design stages with knowledge of the static aeroelastic response while considering nonlinear aerodynamics
Geomicrobiology of Seafloor Basalts and Viral Metagenomes of Seafloor Habitats in the Pacific Ocean
No full textSeafloor basalts, inactive sulfides, and seamounts represent broadly distributed biospheres on the seafloor. Here, the microbial community composition, functional potential, and extracellular enzyme activity rates were assessed within these seafloor habitats, with an emphasis on seafloor basalt samples. Extracellular enzyme activity assays were performed using seafloor basalt from the East Pacific Rise (EPR) 9��50'N and Davidson Seamount, to understand their role in carbon, nitrogen, and phosphorus acquisition. Metagenomics was also used to evaluate the differences in the microbial community composition and functional potential of seafloor basalts from two different age groups represented by two separate eruptions at EPR 9��50'N. Viruses from metagenomes of seafloor basalts, inactive sulfides, and ferromanganese crust from the EPR 9��50'N, Southern Mariana Trough, PACManus, and Takuyo-Daigo Seamount were also analyzed to characterize the overall viral community composition, auxiliary metabolic gene function, and virus-host linkages. The analyses conducted here offer an insightful understanding of the resident microbial community within seafloor habitats, shedding light on their nutrient acquisition mechanisms via extracellular enzyme activity, and their genetic potential to uptake and utilize nutrients in their environment. In addition, these analyses explore the previously overlooked role of viruses in the survival of the prokaryotic community present. The abundance and importance of these seafloor habitats in the ocean emphasizes the need to understand the ecology of the resident microbial life, and their potentially significant role in marine nutrient cycling
Systematic Uncertainty Quantification of MCNP Predicted Nuclide Concentrations in Fuel Burnup Simulations
No full textMonte Carlo N-Particle transport code (MCNP) is often used to simulate nuclear fuel burnup and depletion because it is efficient in solving the radiation transport equation for complex geometries. MCNP simulates fuel burnup and estimates the concentrations of actinides and fission products generated in the fuel, which are useful in nuclear forensics as well as safeguards monitoring. During fuel burnup simulations, the uncertainties in the predicted nuclide concentrations due to the uncertainty in the nuclear data used by MCNP are not propagated and predicted. The nuclide concentration is calculated through CINDER 90 isotope generation and depletion module in MCNP. The CINDER90 module uses the neutron reaction rates and flux values computed by MCNP for each burnup time step. The reaction rates can be broken down into three terms: neutron flux, number density of the target isotope that is transmuting, and microscopic neutron interaction cross section. The number density and neutron flux are provided by MCNP; however, the microscopic cross sections are not directly provided by MCNP in the output and will contain systematic uncertainty in varying degrees depending on the microscopic cross section of the target isotope of interest. Systematic uncertainty is not propagated through each MCNP burnup time step. Propagating the effects of systematic uncertainty using a Backward Euler numerical scheme allows for the reporting of the systematic relative error in the predicted nuclide concentrations, which the study undertaken in this thesis. This Backward Euler methodology was executed through python scripting and a program was developed to output the systematic relative error for user desired isotopes of interest utilizing on the results of MCNP fuel burn up simulation. It was concluded that the Backward Euler methodology and the Bateman equations successfully replicated the MCNP estimated concentrations given the appropriate one group cross sections. Additionally, it was determined that for select isotopes of interest the systematic uncertainty for the associated concentration can be estimated
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
Exploiting Plant-Based Protein Functionalities Through Tannin-Mediated Structural Modification and Application as Texturized Vegetable Protein (TVP��) and Edible Film
No full textThe surging global demand for alternative diverse and sustainable sources has been driven by an increasing global population and a growing number of health-conscious consumers. The current trend has caused a significant focus on pulse proteins as a potential alternative, primarily because of their exceptional nutritional profile and the reduced consumer concerns surrounding allergens, and negative perception. As a result, research initiatives are now underway to improve the functionality and value of pulse proteins, with a specific goal of enhancing their role as alternatives meat source as texturized vegetable proteins (TVP��) and edible films. The major obstacle for pulse proteins is their limited effectiveness when compared to conventional sources. Pulse proteins face limited competitiveness due to high solubility and low cross-linking propensity in comparison to traditional meat sources. This stems from their high solubility and a low propensity for cross-linking, which affects their ability to imitate the texture and structure of the meat. To address these areas, this research primarily revolves around the utilization of polymeric polyphenols, specifically proanthocyanidins (PA), to modify and enhance the structure and rheological properties of pulse proteins. The fundamental premise of this approach is to harness the abundant biofunctional polyphenols found in tannins to fundamentally alter the characteristics of pulse proteins. This alteration aims to improve key attributes such as solubility, water-binding capacity, and texture. The ultimate objective is to make pulse proteins highly functional and competitive as meat substitutes and edible films, thereby meeting the demands of health-conscious consumers while addressing concerns about the sustainability of food production systems.
In this research, we investigated the effect of PA on pulse protein rheology and film properties and assessed the mechanisms behind these interactions. The main focus of this research was to develop texturized pulse proteins (TXVP) utilizing a twin-screw extruder using pea proteins (PP), lentil proteins (LP), faba bean proteins (FP) and conduct post testing with these texturized proteins extrudates. Commercial pea protein (77.4% protein), lentil protein (81.9% protein), and faba bean protein (80.9 % protein) were prepared for production of texturized vegetable proteins and soy proteins (SP, 66.5% protein) was used as a control.
Polymeric PA from sorghum (mean degree of polymerization, mDP 19.5) dramatically strengthened pulse protein, e.g., at 2.5 mg/g flour. The network of the texturized proteins from the two pulses (pea and faba) also exhibited increased hardness and springiness, which are indications of the protein crosslinking and holding together better with increasing levels of PA. Lentil proteins did not texturize and that of soy was not showing consistent properties. Polymeric surface hydrophobicity of protein (pea and faba) was reduced by PA (69 ��� 75% vs control).
To evaluate the opposite behavior of lentil protein during extrusion (did not texturized because of its high-water holding capacity), lentil protein and pea protein were utilized for making edible films. Polymeric PA increased lentil protein film strength (e.g., at 2.5 mg/g protein, force to extend was 2.3X greater than control without reduced extensibility). Thus, PA may improve lentil film flexibility and structural integrity. Overall evidence indicates PA complexed with pulse protein by hydrophobic interaction and hydrogen bonding. In conclusion, the research outlined in this study holds the promise of transforming pulse proteins into versatile and sustainable alternatives to traditional meat sources and edible films. By enhancing their functionality and competitiveness, this work seeks to contribute to the global effort to promote sustainable food production and meet the evolving dietary preferences of a growing population
Second-hand Illegality: Bureaucratic Exclusion and Resource Inequality in College Financial Aid for U.S.-born Latina/o Children of Undocumented Parents
No full textThis study presents a systematic analysis of the bureaucratic obstacles confronted by U.S.-born Latina/o children of undocumented parents when seeking financial aid for college. It delves into the unique challenges these students face during the financial aid application process, where parental information is a pivotal factor. Methods: Employing a semi-structured interview approach, I engaged with 15 participants who shared their experiences with bureaucratic barriers when parental information was requested. The study unveils the concept of "Second-hand illegality," where participants found their own access to resources for education obstructed due to their parents' undocumented status. This phenomenon became most pronounced at three key junctures within the Free Application for Federal Student Aid (FAFSA) form: (1) when the application necessitated parental social security numbers, (2) when it required parent income details, and (3) when it demanded parent signatures for submission. Consulting these points compelled participants to employ innovative strategies to surmount the obstacles. This research underscores a fundamental structural issue within the higher education system, focusing on a demographic often overlooked in immigration literature. The strategies devised to overcome the bureaucratic hurdles posed by the FAFSA lead to outcomes mirroring those experienced by their undocumented parents, including rejection, denial, or limitations on access to crucial resources, services, and benefits. In a broader context, this study highlights the need for systemic changes and policy reform to ensure equitable access to higher education for all U.S. students, regardless of their parental immigration status