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Optimizing Produced Water Treatment in the Permian Basin: The Role of Indirect Evaporative Cooling in Hydraulic Fracturing
No full textThis study investigates the novel application of Indirect Evaporative Cooling (IEC) for treating produced water in hydraulic fracturing operations within the Permian Basin. Utilizing a lab-scale IEC system, we conducted fifteen experiments to assess Total Dissolved Solids (TDS) and volume reduction in produced water, considering variations in initial water volume, composition, and TDS concentration. The experiments included a range of synthetic samples with salinities from 0 to 70,000 ppm and real-produced water from different Permian Basin regions (Delaware, North Midland, and South Midland).
Our findings reveal that IEC's efficiency in TDS removal, achieving near 100% effectiveness for both synthetic and real produced water samples, is primarily influenced by the presence of the most abundant salts rather than the overall TDS concentration. This highlights the system's capability to handle high salinity and diverse impurities typical in oil and gas production waters. Additionally, the IEC system proved to be significantly less energy-intensive compared to traditional thermal evaporation methods.
The economic assessment of IEC versus standard evaporation methods for treating one barrel of water further demonstrates its viability. The study concludes that IEC offers a highly effective, environmentally sustainable, and economically feasible solution for high TDS oil field water treatment. It stands out as a promising alternative to conventional technologies, with potential applications extending across various industrial facilities. This research paves the way for future exploration to maximize the potential of IEC in addressing the wastewater challenges in hydraulic fracturing
The Experiences of Queer Undergraduate Students in Engineering at Two Predominantly White Research Institutions
No full textLGBTQ+ students in engineering are an underrepresented group that is often treated differently in the field. In this study, I use the term queer throughout to describe this population. Engineering is a male dominated discipline comprised of white, cisgender, heterosexual males, and those who differ from this demographic are often perceived as the outsider. While the literature gives attention to queer students in STEM as a whole, few studies address engineering specifically. Progress has been made for the queer population, such as gender-neutral bathrooms and anti-discrimination policies, however, more work is needed across higher education and within STEM for this vulnerable population. This qualitative study examined the experiences of 14 queer undergraduate engineering students at two predominantly white institutions in Texas, 10 from one PWI and four from the other. The study sample consisted of participants who represented a variety of ethnicities, gender identity or expression, sexual identities, and engineering disciplines.
This study used Self-Determination Theory (SDT) and Queer Theory (QT) frameworks to understand how power and privilege either make or hinder academic experiences and choices. Participants shared their perceptions of the engineering discipline as a whole, such as interactions between and among students and professors, and how the major is taught compared to other courses outside of engineering. Participants expressed feeling unlike their peers, invisible in the classroom, and how their gender and sexual identities interfered with their daily lives. Administrators, faculty, families, and peers can learn from the findings to understand the needs of and create safe spaces for queer students in engineering where their identities are affirmed, valued, and heard. They found support during their academic journeys, shared how politics in Texas influenced their perceptions and educational experiences, and described what institutions could do better to help students succeed in engineering. Findings from this study draw implications for systemic change to make queer undergraduate students in engineering feel like they belong
John Bickham field notebook: AK1001-AK1500
No full textBound book, each page corresponds to a karyotype slide data.Data pages for AK1001-AK1500 corresponding to unique identifiers of specimens/samples examined for biological research. Specimens are primarily housed at Texas A&M University; Biodiverstiy Research and Teaching Collection
When Modes of Learning Shift Unexpectedly: How Instructors Choose Online Teaching Strategies
No full textThis study examined how in-person instructors selected online teaching and learning strategies when shifting to a different mode of learning during the COVID-19 pandemic. As many in-person instructors have little to no experience with online learning or instructional design, examining how strategies were selected during this time provides an understanding of what strategies worked, the challenges in shifting to a different mode of learning, and practices that were retained moving back to in-person instruction. The findings revealed that instructors selected strategies during these shifts through adapting existing in-person instructional strategies to address the changing circumstance
Wind Tunnel Data Quality Assessment and Improvement Through Integration of Uncertainty Analysis in Test Design
No full textThe practical application of uncertainty quantification in wind tunnel testing is not consistently or proactively applied. Although there is a solid methodology to quantify uncertainty, the resources required to implement this methodology at the pace of testing while adapting to the unique designs for each test are rarely available. This research combines the use of Monte Carlo simulations for uncertainty quantification with a decision-based integration of uncertainty estimates into the test design process and test execution. This implementation reduces the resources required to routinely quantify uncertainty to a practicable level and aims to proactively affect data quality by incorporating uncertainty estimates into early test design decisions. This methodology is used in the design, execution, and data analysis of a wind tunnel test at the Oran W. Nicks Low-Speed Wind Tunnel (LSWT) at Texas A&M University. The test analyzes the uncertainty in the aerodynamic coefficients and performance parameters of an aircraft test model. After quantifying the uncertainty of the aerodynamic coefficients, this research investigates a potential elemental error source in the measurement of static aerodynamic coefficients due to oscillating nonlinear aerodynamic loads. Notable results from this research include the demonstration of integrating uncertainty analysis with test design in a practical way, reduction of uncertainty intervals in aircraft performance parameters measured in the LSWT by an average of more than 90% through this integration, and experimental evidence of an elemental error source from oscillating nonlinear aerodynamic loads in the measurement of static aerodynamic coefficients
Self-Healing of Bulk Vitrimers as a Function of Thermomechanical Boundary Conditions
No full textThe subject of this study is vitrimers, a class of thermoset polymers with exchangeable covalent bonds, with a focus on their ability to improve material durability in the aerospace, civil infrastructure, and elastomer technology industries while requiring minimal intervention. The material used in this study was procured from ATSP Innovations, provided as a bulk block with the specified dimensions to meet our testing requirements. The selected material, a variant of ATSP characterized as CBAB, was chosen strategically owing to its unique availability in bulk form from the manufacturer at this juncture. This characteristic of CBAB was pivotal for our study as it is allowed for a consistent and uniform sample preparation, an essential factor for the integrity of our fracture mechanics analysis.
To evaluate the bulk fracture, compact tension (CT) tests were done on samples cut out of a panel. The samples were then mended by putting the two halves of the sample together and applying heat and mechanical pressures to study the kinetics of bond formation and their selfrepair mechanisms. Pre- and post-healing fracture toughness measurements were methodically performed, demonstrating a significant restoration of mechanical strength, confirming the effectiveness of the repair procedure. Furthermore, the study investigated the interplay between time and temperature influencing vitrimers ability to self-heal, offering light on the best circumstances for maximal healing efficiency. The time and temperature dependence of the healing mechanism was explained quantitatively by means of an Arrhenius relationship, and the activation energy of the bond reformation was assessed. Furthermore, by revealing the intricate link between stress levels and the healing process, this study sheds light on the fundamental mechanisms governing vitrimer self-repair, paving the path for improved material design and application. A comparison was made between the healing performance of bulk samples and ATSPcarbon fiber reinforced composites, obtained from other studies, to shed light on the effect of confinement (in the composite) on the healing performance of the vitrimers. Crucially, this study emphasizes the critical roles that temperature, time, and stress levels play in shaping the dynamics of self-healing, providing invaluable insights for both advancing our understanding of vitrimers and facilitating their wider adoption in the field of self-repairing materials
Unveiling the Myth Within: The Role of Narrative Perspective in C.S. Lewis' "Till We Have Faces"
No full textThis thesis explores the embodiment and performance of myth through the first-person viewpoint in C.S. Lewis��� Till We Have Faces (Faces). In this novel, Lewis moves away from his previous rationalist approach and uses myth and a first-person narrator to write an intimate story unlike what he had accomplished before. It is a shift in narrative methodology that signifies a corresponding evolution in Lewis��� theology. I study the potential cause of this shift through a study of Lewis��� Christian conversion and an impactful philosophical debate. The result is a particular and unique utilization of myth as a vehicle of conflict, as the protagonist, Orual, is shrouded from reality and must reckon with her own mythology to gain an accurate interpretation of herself and of the divine. I compare the original myth of Cupid and Psyche in The Golden Asse with Faces in order to understand Lewis��� purposes in changing the original story and glimpse the result. Ultimately, he seeks to reveal the importance of coming ���face to face��� with one���s self and holding on to one���s identity. I investigate the theme of identity, as highlighted by the first-person perspective, through the embodiment and performance of myth to argue how Faces is unique among Lewis��� literature
Design and Evaluation of Scancap: A Low-Cost, Reusable Tethered Capsule Endoscope with Digital Chromo-Endoscopy Imaging for Unsedated Screening and Early Detection of Barrett���s Esophagus
No full textEsophageal adenocarcinoma (EAC) is the sixth leading cause of cancer death worldwide. Early detection and treatment of Barrett���s esophagus (BE), a precursor to EAC, increases the five-year survival rate from 18% to 98%. BE is a global challenge; however, current endoscopes for early detection of BE are costly and require extensive infrastructure for patient examination and sedation. We describe the design and evaluation of the first prototype of ScanCap, a high-resolution optical endoscopy system with a reusable, low-cost tethered capsule designed to provide high-definition, digital chromoendoscopic imaging for early detection of BE in unsedated patients. The tethered capsule (12.8 mm diameter, 35.5 mm length) contains a color camera and rotating mirror and is designed to be swallowed; images are collected as the capsule is retracted manually via the tether. The tether provides electrical power and illumination at wavelengths of 415 nm and 565 nm and transmits data from the camera to a tablet. The ScanCap prototype capsule was used to image the oral mucosa in normal volunteers and ex vivo esophageal resections; images were compared to those obtained using an Olympus CV-180 endoscope. Images of superficial capillaries in intact oral mucosa were clearly visible in ScanCap images. Diagnostically relevant features of BE, including irregular Z-lines, distorted mucosa, and dilated vasculature, were clearly visible in ScanCap images of ex-vivo esophageal specimens
The Coordination Between Peptidoglycan Hydrolases and Synthases in Myxococcus xanthus
No full textPeptidoglycan (PG) defines cell shape and protects bacteria against osmotic stress. The growth and integrity of PG require coordinated actions between synthases that insert new PG strands and hydrolases that generate openings to allow the insertion. However, the mechanisms of their coordination remain elusive. Here, I show that moenomycin that inhibits a family of PG synthases known as Class-A penicillin-binding proteins (aPBPs), triggers cell lysis despite aPBPs being non- essential for cell growth. We demonstrate that inhibited PBP1a2, an aPBP, accelerates the degradation of cell poles by DacB, a hydrolytic PG peptidase, in the bacterium Myxococcus xanthus. Moenomycin reduces the mobility of DacB molecules through PBP1a2, potentially promoting the binding between DacB and PG. Conversely, DacB also regulates the distribution and dynamics of aPBPs. These findings reveal the lethal action of moenomycin and suggest that disrupting the coordination between PG synthases and hydrolases could be more lethal than eliminating individual enzymes. The process of sporulation provides a unique scenario in M. xanthus to study PG regulation. Sporulation is the process by which spherical spores are formed in M. xanthus, from its regular rod shape in vegetative cells. Surprisingly, in our model organism, there is complete degradation of PG during this rod-to-sphere transition during chemically induced sporulation as well as during the formation of fruiting bodies. During this process, there is an upregulation of PG hydrolases, enzymes which are usually redundant in bacteria. Lytic transglycosylases, which cleave the glycan backbone, are important for the process of sporulation, and our results identified MXAN_3363 (LtgA) and MXAN_4034 (LtgB) as important for the process of sporulation, the former for glycerol induced sporulation and the latter for both sporulation pathways
Methods for Large-Scale Inference with Application to Genomics Data
No full textGenomic data are subject to various sources of confounding, such as demographic variables, biological heterogeneity, and batch effects. To identify genomic features associated with a variable of interest in the presence of confounders, the traditional approach involves fitting a confounder-adjusted regression model to each genomic feature, followed by multiplicity correction. The first project shows that the traditional approach is sub-optimal and proposes a new two-dimensional false discovery rate control framework (2dFDR+) that provides significant power improvement over the conventional method and applies to a wide range of settings. 2dFDR+ uses marginal independence test statistics as auxiliary information to filter out less promising features, and FDR control is performed based on conditional independence test statistics in the remaining features. 2dFDR+ provides (asymptotically) valid inference from samples in settings where the conditional distribution of the genomic variables given the covariate of interest and the confounders is arbitrary and completely unknown. In genome-wide epigenetic studies, exposures (e.g., Single Nucleotide Polymorphisms) affect outcomes (e.g., gene expression) through intermediate variables such as DNA methylation. Mediation analysis offers a way to study these intermediate variables and identify the presence or absence of causal mediation effects. Testing for mediation effects leads to a composite null hypothesis. Existing methods like Sobel���s test or the Max-P test are often underpowered because 1) statistical inference is often conducted based on distributions determined under a subset of the null, and 2) they are not designed to shoulder the multiple testing burden. To tackle these issues, we introduce a technique called MLFDR (Mediation Analysis using Local False Discovery Rates) for high dimensional mediation analysis, which uses the local false discovery rates based on the coefficients of the structural equation model specifying the mediation relationship to construct a rejection region. We have shown theoretically as well as through simulation studies that in the high-dimensional setting, the new method of identifying the mediating variables controls the false discovery rate asymptotically and performs better with respect to power than several existing methods