• 

  What Defines the Effective Hydraulic Conductivity of a Heterogeneous Medium?

  Vera, Mauricio Alfredo (The University of Arizona., 2018)

  Geologic processes produce heterogeneous porous materials that are complex systems to analyze. This research is focused on the bulk behavior of these heterogeneous media, specifically, the effective hydraulic conductivity (Keff). Specifically, I studied media comprised of two block materials with different K values to understand how the percent composition of the materials and their spatial distribution affect Keff. Two approaches are taken. First, I examine an exponential mixing law, that describes Keff as falling between two end members when the materials are distributed parallel to (arithmetic) and perpendicular to (harmonic) the flow direction. The results, based on examining steady state flow through 990,000 grids with MODFLOW linked with MATLAB, indicate a linear increase in the exponent describing K mixing as a function of the fraction of the high K material included, leading to an expression that estimates Keff with an R2 of 0.982. Second, I show that an approach based on energy dissipation weighting, while difficult to infer visually, returns a perfect explanation of K weighting.
• 

  A Review of Alternative Building Materials in comparison to CMU: Hempcrete, Woodcrete , Papercrete

  Hornby, Rachelle; College of Architecture, Planning and Landscape Architecture; Youssef, Omar; Elzomor, Mohamad Alaa; Esser, Michael; Iuliano, Joseph (The University of Arizona., 2017-05)

  Buildings consume an extraordinary amout of our finite natural resources during their construction and operation. It is imperative we begin to examine more sustainably-produced materials to construct them, as well as lifecycle costs. Concrete is the most widely-used building material in the world, and aggregate forms the majority of its composition. The goal of this research is to compare building materials incorporating renewable aggregate—hempcrete, woodcrete, and papercrete—as alternatives to traditional concrete utilizing nonrenewable aggregates. Comparing and contrasting commercially-available, similar products helps identify feasible applications for these alternatives to concrete that may prove more responsible, sustainable, and cost-effective throughout a building’s lifecycle.
• Mexican American Women and Breast Cancer-Comorbidities, Symptom Frequency, Symptom Distress, Symptom Management, and Social Support

  Burrell, Carlitta Danielle (The University of Arizona., 2018)

  This descriptive secondary data analysis examined the influence of comorbidity on medication use, symptom frequency, symptom distress, symptom management, social support and social network among Mexican American (MA) women with breast cancer. The total sample included 149 participants. The mean age of the sample was 50.49 years old—young compared to the U.S. national average age at breast cancer diagnosis of 62 years old. Nearly half of the women reported no comorbidities (n = 71), and n = 78 reported one or more comorbidities. Significant between groups differences showed that the comorbidity group was approximately 10 years older than the no comorbidity group, used more medications, and had twice the social network than the younger no comorbidity group. While the comorbidity group did report more symptom distress than the no comorbidity group, in both groups, the majority of participants reported moderate to high levels of symptom distress. Likewise, there was a small, significant between groups difference for symptom frequency. In both groups, over half of the participants reported having 3-7 symptoms. Correlations between variables showed a relationship between increased symptom frequency and decreased symptom management, and a relationship between higher symptom distress and lower symptom management. Emotional social support showed a positive influence on symptom frequency and symptom distress, providing evidence that social support is beneficial in improving breast cancer outcomes. Additional findings include evidence that low socioeconomic status (SES) contributes to cancer health disparities. The overall similarity between the groups suggests that the effects of comorbidity may not have as much influence as would be expected, and SES and other social and contextual factors may have an effect of equalizing the groups for some variables measured in this study.
• The Devil’s Midwives: Titiçih, Gender, Religion, and Medicine in Central Mexico, 1535-1650

  Polanco, Edward Anthony (The University of Arizona., 2018)

  This dissertation evaluates Spanish and Nahuatl (an indigenous language spoken by the Nahuas of Mexico) sources to probe tiçiyotl (Nahua healing knowledge) in sixteenth and seventeenth-century Central Mexico. My study covers a 150-mile area surrounding Mexico City and begins in 1538, when Juan de Zumárraga, the bishop of Mexico, oversaw the first trial against titiçih (healing ritual specialists). The temporal scope of my dissertation ends in 1656, when Jacinto de la Serna (rector of the University of Mexico) wrote a manual for priests who ministered to indigenous people, which was the last source to use the term tiçitl (sing. titiçih). Other notable sources and contributions include the investigation of ecclesiastical trials against titiçih in Central Mexico. These trials include biographical information, and in-depth information on ritual practices that add humanness to the abstract descriptions included in European treatises, manuals, and encyclopedias. By unpacking the history of Nahua healing knowledge in a colonial context, this study not only explores Nahua people, it also examines how Europeans processed and interpreted indigenous knowledge, materials, and practitioners. Starting in the late sixteenth-century, the Catholic Church systematically attacked Nahua healers in Central Mexico, particularly women, while Spanish physicians absorbed indigenous knowledge and discarded ritual practices and its practitioners. This has made women invisible in academic discussions of tiçiyotl. By employing non-European sources this study includes the perspectives and views of the “colonized,” that is, the indigenous peoples of Central Mexico. Lastly, this dissertation demonstrates that women were integral to the preservation of healing practices and ritual customs among Nahua people in the seventeenth century, and that women led the resistance against Spanish colonialism, and bore the brunt of its wrath.
• The Effects of Self-Reference on Relational Memory in Young and Older Adults

  Hou, Mingzhu (The University of Arizona., 2018)

  Prior studies suggest that older adults show age-related impairments in relational memory, which may be attributed to decreased ability in basic memory and executive functions. The two studies presented in this dissertation investigated the effectiveness of self-reference, an encoding strategy, on different subtypes of relational memory in young and older adults, and the extent to which the effect varies as a function of individual differences in basic memory and executive functioning. Study 1 investigated the influence of self-reference on two kinds of relational memory, internal source memory and associative memory, in young and older adults. Forty young and 40 older adults encoded object-location word pairs using the strategies of imagination and sentence generation, either with reference to themselves or to a famous other (i.e., George Clooney or Oprah Winfrey). Both young and older adults showed better memory performance in the self-referential conditions compared to other-referential conditions on both tests, and the self-referential effects in older adults were not limited by low memory or executive functioning. Study 2 investigated the effectiveness of self-reference on memory for multi-element events. Thirty-six young and 36 older adults imagined person-object-location events with reference to themselves, George Clooney or Oprah Winfrey, and were later assessed on their memory for the events via multiple, cued, forced-choice recognition tasks. Self-reference was found to increase memory for the multi-element events in both young and older adults, and the benefit of self-reference was not correlated with memory functioning in either group. Further, self-reference did not increase memory coherence—the extent to which the retrieval outcomes of different pairwise associations within the imagined events were dependent on one another. These findings are discussed in terms of the potentially different binding mechanisms involved in self-related and non-self-related memories. The results of these studies also suggest that self-reference can benefit relational memory in older adults relatively independently of basic memory and executive functions, and may be a viable strategy to improve relational memory in individuals with different levels of neuropsychological functioning.
• Evaluating the Roles of Recovery Sleep and Emotion Regulation in Fire Service Shift Workers

  Kelly, Monica Rae (The University of Arizona., 2018)

  Sleep, stress-related processes, and emotion regulation are all implicated in mood disturbance and mental health difficulties. The relationships between these variables are especially important for individuals working in public safety professions. Fire service workers are regularly exposed to traumatic events and occupational stressors such as shift work. A majority of firefighters and paramedics endorse sleep deprivation and are at an increased risk of mental health problems. Several days of recovery sleep following sleep loss is required for a return to baseline functioning. Although there is a bidirectional relationship between emotion regulation and sleep, little is known about the relationship between recovery sleep and emotion regulation in terms of negative mood outcomes. This dissertation project aims to better understand the relationship between sleep, stress, and emotion regulation. More specifically, this project encapsulates (a) a review of the recent literature regarding sleep-related mechanisms, characteristics, and treatments in posttraumatic stress disorder as well as (b) findings from a study examining the relationship between recovery sleep and emotion regulation strategies in fire service shift workers. This is the first study to our knowledge to examine sleep patterns in fire service shift workers during the recovery period using gold-standard, prospective measures of sleep. Findings suggest greater average sleep quantity and efficiency are associated with lower average negative mood. Additionally, emotion regulation style moderates the relationship between daily recovery sleep and next day negative mood. Our results further inform our understanding of the interaction between sleep, emotion regulation, and negative mood and may help guide development and implementation of interventions for individuals in public safety professions exposed to traumatic and occupational stressors.
• New Instrumentation and Methods for Analyzing Biological Compounds for Drug Discovery and Discovering Novel Disease Markers

  Sandy, Kendall Elizabeth (The University of Arizona., 2018)

  Ligand-receptor interactions mitigate intracellular responses, with abnormal signaling corresponding to different disease states. G-protein coupled receptors currently compose 50% of drug targets, signifying their importance in the pharmaceutical industry. Therefore, monitoring the binding events of ligands to receptors within the cell membrane is highly important for drug development. One key limitation of accurately monitoring ligand binding to a transmembrane protein is the reconstitution of the protein. Many platforms lack conformational freedom for reconstituted membrane proteins, affecting ligand binding measurements. This work developed a new liposome shell microparticle platform to tether lipid vesicles, which provide conformational freedom for the protein. These particles can be used in a pull-down assay for identification of ligand-receptor binding pairs. CHO-K1 cell membranes containing 5-HT1A receptors were tethered to sulfonate modified particles. NAN-190, a fluorescent 5-HT1A antagonist, binding to 5-HT1A receptors was monitored using flow cytometry. Liposome shell microparticles may also be used in packed bed membrane-based liquid chromatography. To retain the particles a frit is needed within the column. In this work a new thermal polymerization method for fabrication of on-column frits was developed. This method has advantages including a short polymerization time, ease of frit placement within the capillary, minimal and inexpensive equipment and retention of the polyimide capillary coating. Thermal frits were synthesized within a packed bed column and allowed for separation of phenolic acids and aliphatic amines. Frit stability and reproducible retention times demonstrate the utility of this new method for frit synthesis. Lipid vesicle heterogeneity may also affect ligand binding. Lipid membranes can be doped with fluorescent lipids and/or fluorophores can be encapsulated within sensors. However, liposome composition measurements are currently limited to bulk solutions. To understand the liposome composition on a single vesicle/sensor level, a nano flow cytometer was built. This instrument uses a sheath flow cuvette combined with laser induced fluorescence detection for high sensitivity measurements of single vesicles. 200 nm and 400 nm DOPC vesicles doped with varying amounts of PE-CF lipid were measured. Single vesicle resolution was obtained through optimization of the sheath and capillary flow rates. These measurements revealed heterogenous lipid distribution within the same vesicle population. The single vesicle measurements using this instrument allow for more quantitative measurements when using fluorophores.
• Novel Antennas, Matching Circuits, and Fabrication Techniques at HF and Microwave Frequencies

  Gulati, Gitansh (The University of Arizona., 2018)

  This thesis focuses on the investigation of several novel antennas including electrically small antennas for HF communication system, as well as the applications of gradient index lens based broadband multiple-beam system, and electromagnetic cloak structures in printed technology. Modern-day wireless communication systems have developed interest in the field of low-profile broadband antennas. The design of electrically small antennas (ESA) presents numerous challenges, primarily due to inherently low impedance and narrow bandwidths. Improving these performance characteristics becomes even more challenging in the high frequency (HF) band due to longer wavelengths and corresponding antenna physical dimensions. In this thesis, we propose electrically-small vertically-polarized normal mode helical antenna (NMHA), about λ/50 at the lowest frequency of operation, to facilitate robust long-range HF-band communications (3 – 30 MHz). To overcome the potential issues related to electrically-small NMHA such as impedance matching, bandwidth and radiation efficiency, passive and active impedance matching techniques are investigated. Three types of matching networks are proposed, designed and experimentally demonstrated. These include passive narrowband electronically-switched LC matching network, broadband transformers and active non-Foster broadband matching circuit. In addition, performance of electrically-small helical antenna (ESHA) matched system in terms of received signal power strength, signal-to-noise ratio (SNR), and signal intelligibility is evaluated with the help of outdoor field test measurements. Many potential areas of application such as satellite communication, air-traffic control, air-based tracking and surveillance, marine navigation, and automotive radar require highly-directional wide-angle beam scanning with minimum pattern deformation and broadband behavior, in addition to lower-cost and weight considerations. In view of this, another area of concentration addressed by the thesis is towards the development of multiple-beam Luneburg lens antenna system. The additive manufactured 3D graded-index Luneburg lens is employed for this application. Using the special property of a Luneburg lens that every point on the surface of the lens is the focal point of a plane wave incident from the opposite side, compact conformal dual-polarized all-metal Vivaldi feed array, with its phase center close to the lens surface, is proposed to realize the full potential of Luneburg lens for practical wireless applications ranging from 3 – 6 GHz. Lastly, this thesis discusses another interesting topic about electromagnetic invisibility and cloaking technology being applied to printed antennas in order to reduce mutual near-field coupling, based on the concept of mantle cloaking method. Two microstrip-fed monopole antennas placed in the near-field of each other, resonating at slightly different frequencies, become invisible to each other by cloaking the radiation part of each antenna. The cloak structure is realized by a conformal elliptical metasurface formed by confocal printed arrays of sub-wavelength periodic elements, partially embedded in the substrate. The existence of the metasurfaces leads to restoration of the radiation patterns of the antennas as if they were isolated. Finally, the fabrication of near-field cloaked prototype is carried out using advanced 3D printing techniques.
• Development of 248nm AR Coatings for Photolithography Applications

  Bohac, Michael Thomas (The University of Arizona., 2018)

  A key application for thin film coatings, minimizing Fresnel reflections from each surface is critical to achieving high throughput for multi-component, transmissive optical systems. Assuming small, plano optics, reflection from a single laser-line operating near normal incidence can be significantly recovered using a relatively simple antireflection design. Limited in low-reflection bandwidth however, these simple designs increase quickly with angle and/or small amounts of non-uniformity, and become inadequate for large-diameter, fast systems. At ultraviolet wavelengths, the demand for throughput becomes even more challenging, driving system designs to larger apertures and faster, steeper elements. Unfortunately, many thin film materials begin to absorb strongly in the UV, limiting the number of high index options in particular. In addition to inherent material absorption, UV wavelengths are considerably more sensitive to other sources of loss such as scatter and contamination, which must therefore be minimized in combination with reflection. In this study, we studied the trade-offs between low-reflection bandwidth and absorption. By maximizing index contrast, a wider band could be achieved, but often at the expense of absorption from high index materials. A survey of materials was also conducted, where the influence of process energy on contamination was examined. Secondary attributes such as mechanical durability, UV laser damage resistance, and homogeneity were also considered. Once optimized, attention would turn toward multi-layer design and manufacturability, where development results were scaled into a robust and stable multi-layer process. In an effort to reduce the amount of bandwidth consumed by the process, sources of both random and systematic errors were addressed, uniformity minimized, and process repeatability maximized. Conversely, once angle shift and non-uniformity were accounted for, AR bandwidth determined the amount of error the design could tolerate, and thus the level-of-effort required to stabilize the process. The final combination of materials and processes achieved a preliminary loss (reflection + absorption) of 25% through 42 spherical and aspherical surfaces, exhibiting very high laser damage resistance and mechanical durability. Once demonstrated, the process was then applied to two additional systems, improving in performance with each iteration, and ultimately achieving a minimum loss of <23%.
• Soil Microbial Activity is Stabilized by Mesquite in Recreational Campsites

  Kariuki, Sudan (The University of Arizona., 2018)

  Recreational camping often suppresses vegetation cover and expands bare ground. These shifts have important implications for plant and soil ecological health. Soil microbial activity can inform understanding of how recreation affects ecological processes. This case study uses campsites at the Santa Rita Experimental Range in Southern Arizona to test the hypothesis that the degrading impacts of camping on vegetation are mirrored in the soil microbiome. Measurements of herbaceous basal cover, microbial biomass, and enzyme activity were collected and stratified by categories of camping disturbance and mesquite (Prosopis velutina) cover. Campsites demonstrated suppressed litter, herbaceous cover, and gravimetric water content. Herbaceous cover was 53% lower in campsites than in undisturbed areas. Surprisingly, enzyme activity and microbial biomass C and N were more influenced by mesquite canopy (microbial biomass C by 55% and microbial biomass N by 52%) than by camping disturbance. In spite of observed evidence that campsite soil environments are degraded, mesquite-driven ecological processes appear to stave off degradation of soil microbial activity. However, soil microbial biomass and enzyme activity are indirectly affected by camping disturbance through the combined influence of litter, herbaceous cover, and soil moisture. Therefore, plant-soil feedbacks play an important function in determining how campsites in semiarid systems respond to disturbance.
• Imagining Villa: An Examination of Francisco “Pancho” Villa through Popular Culture and Collective Memory, 1910-2015

  Macias, Marco A. (The University of Arizona., 2018)

  Villa’s memory still permeates the fabric of Mexican society throughout popular culture and collective memory. Why Villa survives through myth continues relatively unexplored. To analyze the origins of the myth and it construction over time provides an understanding of how ordinary people participated in fashioning their own ideas of nationalism. This dissertation traces the myth of Villa as a social construct of ongoing inventions of traditions started in the 1910's and preserved in the 1920's by veterans that formed collective memories premised in the creation of the División del Norte. It further describes and analyses how from the 1930's onward, these collective memories were transplanted to a wider audience by mass media; further shaping imagined perceptions that in one way or another persist until our day. In crafting this discourse, I examine newspapers, music, political cartoons, comic books, movies, and ephemera to show how Villa’s image is a social/cultural construct brought together by the synergy of popular culture and collective memory that over the twentieth century produced a carefully woven, multi-faceted narrative.
• Utopian Projects and the Troubled Paradise. Grassroots Discourses and Strategies of Change at the Periphery of Fortaleza, Brazil.

  Mandache, Luminita-Anda (The University of Arizona., 2018)

  In Brazil, inequality, segregation, and urban violence go hand in hand. Not surprisingly, Fortaleza, a city situated in Northeastern Brazil, is the world’s second most unequal city and also Brazil’s most violent. This dissertation aims to understand how residents of the poorest area of Fortaleza—Conjunto Palmeiras—respond to these problems. Conjunto Palmeiras is an extremely poor neighborhood and has the highest homicide rates in the city, yet it is also an important site of activism. Therefore, I seek to understand the tensions between poverty and activism present throughout the history of this neighborhood. What does Conjunto Palmeiras tell us about how marginalized people living in a peripheral neighborhood manage to create and develop political imaginaries of change and act upon them? I ask this question with reference to three historical moments between 1970 and 2017 when collective attempts of problem-solving are clearly evident. The first of such episodes is represented by 1970s to late 1990s period, marking the military dictatorship in Brazil, but also one in which a wave of social movements accompanied the democratization process. The second of these moments is represented by the period 2002 to 2016, which in Latin America, in general, marked the Pink Tide, an era of governance by leftist parties, specifically by the Workers' Party (PT) in Brazil. My focus here is on understanding the contradictions embedded in the institutionalization of a once grassroots project—the solidarity economy movement, rooted in liberation theology—into a state-sponsored program. The third moment is the period between 2015 and 2017, characterized by an increase in drug-related violence in Fortaleza, related to the presence of large drug factions (locally called facções). This dissertation emphasizes that the creation of local political imaginaries, upon which activists developed particular strategies, has been constantly shaped by activists' personal life experiences and interaction with both liberation theology and PT leaders. Shifting understandings of the political landscape reshaped perceptions of poverty and ways to tackle it at the local level. In Brazil, the 13 years of the PT governance put in place a set of socio-economic programs that enabled social mobility for the country's historically marginalized groups. However, during this period, the discourses of older social movements that promoted an egalitarian ideology and a working-class consciousness were replaced with more neoliberal and individualistic understandings of poverty. According to this view, poverty is the result of economic marginalization and can be eradicated by “inclusion” in the market. Yet, over the years, the consciousness-raising process necessary to the formation of a working-class consciousness developed by the liberation theology movement, contributed to the creation of a certain political imaginary among former movement members that inspires the strategies of some local activists. For example, with the increase of homicide rates in Fortaleza, drug related violence emerged in places like Conjunto Palmeiras as a generator of new forms of resistance, where activists dare to challenge the presence and authority of drug gangs through symbolic practices. This phenomenon of change challenges current trends in “resistance” studies to romanticize social movements and portray local leaders as heroes since it situates such forms of activism into larger historical processes of change, which can only be understood in close relation to most activists’ daily experiences with poverty.
• Co-Curricular Technology Engagement and its Effects on Arabic Language Learner Motivation, Autonomy, and Language Proficiency

  Alhomsi, Riyad (The University of Arizona., 2018)

  Numerous research studies have been conducted in the area of technology integration in second language learning and its effects on learner motivation and learner autonomy, the studies have been mainly Eurocentric with a focus on English (Carr, Crocco, Ezring, & Galego, 2011; Ducate, & Lomicka, 2008; Loucky, 2005; Warschauer, 1996; Aust et al.,1993; Laufer & Levitsky-Aviad, 2006; Sougari & Hovhannisyan, 2016). Very little research has been conducted about other less commonly taught languages such as Arabic. Moreover, most of the research focused on the affective aspect of technology integration and not on the potential language gains that learners can get from this integration. Keeping this in mind, and given that Arabic occupies the eighth place in the top fifteen foreign languages taught in the United States institutions of higher education, more research is warranted to investigate aspects related to teaching Arabic, especially the effects of technology integration on improving language proficiency, learner motivation, and learner autonomy. This study has contributed to the literature by examining technology integration effects on the Arabic language learner motivation, autonomy, and language gains. Findings from this study seem to support findings from other studies that technology integration increased learner motivation and improved attitude (Aust et al.,1993; Laufer & Levitsky-Aviad, 2006, Sougari & Hovhannisyan, 2016). However, this study found that the correlation between technology use and motivation is not automatic and is only true when: 1) Technology use has a tangible impact on language abilities, 2) Technology use provides resources and tools that support learning and make it more accessible, 3) Technology use makes learning easier and less time consuming, and 4) Technology presents diverse tools to learn or practice different language skills. The study also examined how technology use changes learner engagement in autonomous out-of-class learning activities. Findings suggest that learners have a positive attitude on the versatility and affordances of technology. Moreover, the participants are not only aware of the affordances of technology, more importantly, they seem to have built a clear vision of themselves beyond the classroom and how to achieve that vision. This is a clear indication of an autonomous learner who is able to set their own goals, and the means to achieve them. The findings also indicate that technology can provide tools that motivate learners to take control of their learning and extend it outside the conventional learning setting. It can personalize the learning experience and help develop a sense of ownership. These findings line up with findings from other studies which indicate that technology promotes ownership and personalized learning (Guth, 2009), supports independence and out-of-class engagement (Pinkman, 2005), and encourages self-directed learning activities (Luke, 2006). The last part of the study focused on the effect of the general use of technology on language proficiency, specifically, fluency and accuracy in the writing skill. Fluency was defined as increased number of words produced in a timed writing session, and accuracy was defined as the number of two types of errors (the noun/adjective agreement errors and the subject/verb concordance errors) committed in these writings. Findings from this part of the study show that there is a correlation between technology use and improved writing skill; however, the findings were not statistically significant due to different factors such as the small number of participants. The study has wider implications for different stakeholders in the educational system including Arabic language teachers, foreign language teachers, Arabic language learners, and educational institutions.
• The Gut Microbiota Crosstalk with the Host Immune System in Health and Disease

  Felix, Krysta M. (The University of Arizona., 2018)

  The gut microbiota both regulates and stimulates the immune system to impact many aspects of immunity, including the response to infection and the development of autoimmunity. This is driven in large part by the unique environment of the mucosal tissues, where host cells reside in close proximity to the microbiota. The mammalian host incorporates barriers and mechanisms to control interactions with the microbiota, and significant cross-talk occurs between the microbiota constituents and the innate and adaptive elements of the host immune system. While great strides have been made in defining how the microbiota affects the host, particularly in regard to intestinal immunity and function, more remains to be determined regarding how the gut microbiota impacts gut-distal diseases. Here, we demonstrate that the gut commensal Segmented Filamentous Bacteria (SFB) is protective in a mouse model of pneumonia in immunodeficient hosts. During the resolution phase of disease, lung neutrophils are decreased, and undergo a phenotypic switch from inflammatory to pro-resolution, mediated in part by downregulation of the anti-efferocytosis transmembrane glycoprotein CD47. We also show that the purinergic receptor P2X7 is potentially required in a T cell-intrinsic manner to control the development of disease in autoimmune arthritis. T cell immunoglobulin and ITIM-containing (TIGIT) levels are upregulated on P2rx7-/- T follicular helper (Tfh) cells, which may contribute to deregulation of cell death and expansion of the Tfh population. This work contributes to our understanding of how the gut microbiota impacts gut-distal infection and autoimmunity through changes in innate and adaptive immune cells.
• Application of Machine Learning Algorithms in Hydrocarbon Exploration and Reservoir Characterization

  Keynejad, Saba (The University of Arizona., 2018)

  This dissertation presents novel approaches to evaluate complex seismic and well-log data using machine learning algorithms with examples from two different hydrocarbon fields. The applicability of these algorithms for predicting and classifying direct or indirect hydrocarbon indicators are assessed and compared to knowledge-driven methods. The efficacy of the various techniques leads to recommendations for utilizing machine learning algorithms in well planning or later cycle hydrocarbon-field development. In the first study in this dissertation, application of a model-based artificial neural network is compared to the performance of a prestack simultaneous inversion method in predicting hydrocarbon presence in the Heidrun Field, offshore Norway. Low-frequency initial models were used to create 3D Poisson’s ratio models to reflect the fluid within this field and the results were compared based on the accuracy and generalization power of the two methods. The results of both methods confirmed Poisson’s ratio to be a good direct hydrocarbon indicator within the wells used from this field. The direct dependency of the inversion method on the provided input constraints, however, can raise the risk for well planning decisions beyond the known zones. The generalize regression neural network results better matched the observations at the training wells and provided a lower risk of false discoveries in delineating favorable zones beyond the drilled wells. The second study was conducted with the aim of classifying different facies from well logs in wells of the Heidrun Field and in the Kupe Field, offshore New Zealand. Different machine learning approaches were utilized in this study and to investigate quantitatively and qualitatively the accuracy and stability of their predictions. Both supervised methods could successfully predict hydrocarbon-bearing units, with the bagged tree algorithm having a higher overall, and hydrocarbon-related, accuracy rate. Application of the bagged-tree algorithm showed a very low false discovery rate for oil sands and no false discoveries for gas sands in the Heidrun Field. A misclassification of oil sands as brine sands in one Heidrun well is in agreement with relatively high Poisson’s ratios as discussed in the first study. Qualitative investigations of Kupe Field results also demonstrated accurate prediction of hydrocarbon-bearing units, including a shaly hydrocarbon sand class defined for low-quality reservoir sands. Hydrocarbon shows reported in one well that were not predicted by the algorithm, in fact, occur in a very low-porosity section of the reservoir that was not identified as reservoir in reports either. In the last study, the classifications of the litho-fluid facies were extended to three dimensional models using two machine learning methods and were compared with a knowledge-driven approach. The results were examined through a probabilistic approach to reflect the uncertainty of the predicted classes. The probabilistic neural network and the bagged-tree algorithm successfully predicted the variations of litho-fluid facies, especially for hydrocarbon units. Both methods predicted gas sands in certain parts of the field, away from control points, with similar form and lateral dimension. By comparing the results in predicting oil sands and shale, we interpret the bagged-tree method to be more adherent to the known parameters set by the interpreter, such as the OWC and the target classes. Predictions from the probabilistic neural network, however, can deviate from the target facies even close to the wells on which it has been trained. The efficiency of machine learning techniques in increasing the prediction accuracy and decreasing the procedure time, and their objective approach toward the data, make it highly desirable to incorporate them in seismic data analyses. Along with the emphasis on the application of machine learning techniques in the study of subsurface properties, this dissertation presents frameworks for utilizing these techniques as new tools for the interpreter, not as a replacement. The knowledge of the data analyst about the field, and the selection and preparation of the attributes and application of the appropriate algorithm are all crucial factors in this procedure.
• Selected Topics in Advanced Optical Design and Engineering

  Gao, Weichuan (The University of Arizona., 2018)

  Optical imaging has seen significant development over the last few decades thanks to the advances of light sources and innovative imaging modalities. New quests have opened for advanced optical system design and engineering that require comprehensive understanding of theory and extensive computer simulations. This dissertation discusses several selected topics in advanced optical design and engineering, including new optical design considerations for systems with ultrafast illumination, engineering of a reflective microscope system in the vacuum ultraviolet and a method to design apochromat and superachromat objectives. For optical systems with ultrafast illumination, a modified definition of Strehl ratio is proposed to quantify chromatic and temporal behavior of ultrafast laser pulses at the optical focus. A simple method to obtain approximate numerical solutions is given with the help of ray tracing software. Effects of monochromatic aberrations, material dispersion up to the second order and pupil aberrations are discussed. System engineering of an imaging microscope illuminated with hydrogen Lyman-α line at 121.6nm is discussed. Challenges of diamond turning fabrication technology are described. Alignment and testing procedures are presented. A correction phase plate design is proposed for improving the as-built system performance, and a sensitivity analysis is carried out. For future work, a new two-stage system design is proposed to address the limitations of the current system. A simple method to design apochromats is proposed, where an apochromat is formed by combining two achromatic doublets with proper scaling of the focal lengths. A scaling formula is derived to calculate the focal lengths of each component. The formula is developed for lenses in contact and remote lenses with different marginal ray heights.
• Image Segmentation and Analysis Methods and Their Evaluation on Synthesized Porous Media Data

  Kulkarni, Ramaprasad (The University of Arizona., 2018)

  Nondestructive imaging techniques such as X-ray computed tomography (CT) provide powerful means for quantitative analysis of porous material properties. Three-dimensional reconstructions from segmented X-ray CT images yield detailed information about density distribution, pore structure, pore connectivity, and phase interfaces that can be applied as boundary conditions for fluid dynamics simulations. However, accurate segmentation of grayscale X-ray CT data to discern solid medium constituents and fluid phases remains a significant challenge. To advance image segmentation, one objective of the dissertation research was the development of a new semi-automated multiphase segmentation algorithm combining K-means (KM) clustering with a Markov random field (MRF) framework. X-ray CT data were segmented with the new KM-MRF algorithm and with KM clustering only. A comparison of segmentation results shows that in the presence of noise inherent to X-ray CT data acquisition, KM-MRF yields fewer misclassification errors than sole KM clustering. Because the exact phase (i.e., solid, liquid, and air) boundaries of an imaged porous medium are not known a priori, there is no reliable reference data for meaningful validation of porous media segmentation algorithms. To overcome this problem, a second objective of the dissertation research was to synthesize a three-phase porous medium proxy with exactly known phase boundaries by using a discrete element method in conjunction with lattice Boltzmann fluid dynamics simulation. This approach generates an artificial porous medium with known phase boundaries, comprising spherical particles along with liquid and air. Poisson noise was added,and the contrast and resolution of the synthesized medium were varied to simulate image degradation experienced during X-ray CT data acquisition. The degraded data were then used to compare the performance of the KM-MRF, KM clustering, multi-Otsu and multi-SVM segmentation algorithms. The Dice and Jaccard similarity coefficients, and the misclassification, volume fraction, and surface area errors were used as performance criteria. The final objective of the dissertation research was the development of an efficient algorithm for quantification of phase interfacial area, a governing property for many porous media processes related to contaminant transport and remediation. An improved surface area estimator for three-dimensional objects based on the local Gaussian curvature was developed and compared with state-of-the art weighted-voxel techniques for five basic geometries. The relative error for the newly developed method was significantly smaller than the errors obtained with the competing weighted-voxel methods for objects with a combination of planar and a small proportion of curved surfaces, and comparable for objects with at least some proportion of curved surfaces.
• Enabling Alternative Islet Sources for Use in Islet Transplantation

  Smith, Kate Elizabeth (The University of Arizona., 2018)

  Implementation of islet transplantation as the standard of care for patients with Type 1 Diabetes (T1D) is restricted by a shortage of human donor pancreata from which to isolate islets and the need for systemic immunosuppression post-transplantation. To address the first problem, alternative islet sources have been pursued. In particular, porcine islets have emerged as a promising option. However, the optimal age of porcine donor for human translation has not yet been determined. For example, adult porcine islets provide immediate function, but neonatal islets are more logistically feasible to isolate. Encapsulation, which prevents contact between transplanted islets and recipient immune cells, has been proposed to address the second limitation. While encapsulation can effectively enable transplantation without immunosuppression, only limited success has been achieved with encapsulated porcine islets. Together, this illustrates the need to re-evaluate porcine islets as an alternative source to human islets. Specifically, they should be evaluated under encapsulated conditions in order to delineate their specific needs, and to determine the most suitable age for translation to encapsulated cell therapeutics. To facilitate the application of porcine islets, adult (API), juvenile (JPI), and neonatal (NPI) porcine islets were first characterized under unified protocols to quantify differences in oxygen demand, viability, insulin secretion, proliferative capacity, and transcriptomes under baseline conditions. Next, changes in API and NPI viability, function, and transcriptomes were characterized under various oxygen conditions which mimic encapsulation; ischemia (high density encapsulation with no supplemental oxygen), hypoxia (1% O2, encapsulation prior to device vascularization), and hyperoxia (40% O2, supplemental oxygen to facilitate high density encapsulation). Under control conditions, oxygen demand did not differ by age. Consistent with previous literature, API were determined to have the greatest glucose-responsiveness and secreted approximately 50 times more insulin under stimulatory conditions than NPI or JPI, consistent with significantly higher insulin content. NPI and JPI β-cells were significantly more proliferative than those in API. Accordingly, NPI transcriptomes were enriched for transcripts associated with cellular proliferation, but also demonstrated greater expression of transcripts encoding for known xenoantigens. Because JPI and NPI properties were nearly identical, JPI were not further evaluated. Contrary to expected results, few differential responses were evident between API and NPI following ischemic, hypoxic, or hyperoxic exposure. Accordingly, NPI did not demonstrate resistance to hypoxic exposure and instead exhibited impaired proliferative capacity. Given that the responses of API and NPI to ischemia, hypoxia, and hyperoxia were found to be similar, either population would be suitable for encapsulation with enhanced oxygenation. Because API are immediately functional, require a lower curative islet dose, and express fewer xenoantigens, they may be more suitable for clinical translation in the near term. However, as maturation protocols for NPI are developed and standardized, they may be a more efficient option in the long term.
• The Political Cultures of American Study Abroad Initiatives in Latin America and Spain

  O'Toole, Leslie (The University of Arizona., 2018)

  The production and representation of study abroad in Latin America is examined through the following theoretical framework: consumer culture, visual studies, media convergence, film analysis and critical discourse analysis. The second chapter is an analysis of the representations of Latin America and Spain in modern study abroad marketing collateral. These materials range from paper pamphlets and brochures to online content on the various websites of different for-profit and not-for-profit study abroad agencies, as well as different universities. They are representative of three randomly selected for-profit study abroad agencies, and one randomly selected not-for-profit study abroad agency. For the universities, 6 different universities have been randomly selected and includes two small liberal arts colleges, two large research universities, 2 community colleges, and two historically Hispanic-serving institutions. This sample provides the most accurate data that surveys the largest possible variety of study abroad agencies in the field. The third chapter analyzes a variety of travel blogs written by study abroad students and instructors and directors of study abroad programs in Latin America. These blogs are selected based on a narrow criteria: they are written by students, instructors, or directors of study abroad programs in Latin America; are written during the author’s time in Latin America; the total number of blogs selected represent at least three different countries in Latin America. This chapter also evaluates the social media posts on Facebook and Twitter of students studying abroad in Latin America using Henry Jenkins’ theories on convergence culture and participatory culture. Often study abroad students will create a Facebook group in order to connect with other students studying in the area or on the same program. This chapter aids in linking the discourse analysis of the previous chapter together to provide a more holistic picture of how Latin America is portrayed in US study abroad discourse through its use of theories from Henry Jenkins, Edward Said and Mary Louise Pratt, among others. Specifically, this chapter is interested in exploring how students talk about these regions when writing for different types of audiences, for example: Facebook versus a personal blog directed towards family. The ways in which Latin America is represented and discussed on these different media platforms provides a certain insight as to whether or not study abroad programs are successfully creating global citizens or simply perpetuating stereotypes. The fourth and final chapter of this dissertation focuses on how study abroad is represented in young adult literature. Each book portrays a teenage girl going off and studying abroad for a year in a different country, from Spain to Mexico. This final chapter seeks to glean how the representations of study abroad programs in their marketing materials and social media responses by students influence the representation of the culture of study abroad in these cultural manifestations. The use of Michel Foucault’s definition of discourse, as well as Fredric Jameson’s description of postmodernism, and Antonio Gramsci’s hegemony, will all aid in the understanding of how the culture of study abroad manifests itself within cinema and literature. This dissertation questions the representations of Latin America in study abroad discourse and how these visual and textual narratives are eventually represented in cinema and literature. Each chapter argues that a hegemonic form of discourse has shaped the nature and role of U.S. study abroad in Latin America, as well as, in cinema and literature. The chapters also point directly or indirectly at the role of policies and approaches from the top down in study abroad rhetoric, including the importance of global citizenship in program mission statements, the manner that students and program administrators discuss their experiences while studying abroad on social media and blogs, and how study abroad is represented in cultural manifestations from cinema to literature. The interdisciplinary approach and triangulation of these topics expose a consistent history of hegemonic tropicalization and orientalism of study abroad destinations and calls into question the marketing techniques utilized by U.S. organizations to promote and sell their vision of study abroad. It is important to study the history of this rhetoric so that we may bring attention to it and, at some point, integrate alternative visions and narratives into its fold.
• Explanatory Models of Mexican-American Women with Type 2 Diabetes Living in the Colonias

  Smith, Emily Marie (The University of Arizona., 2018)

  Type 2 diabetes (T2DM) affects more than 30 million Americans. Hispanics are more likely to be diagnosed with diabetes and are more likely to suffer from diabetes-related complications and mortality than non-Hispanic whites. Due to its large concentration of Mexican Americans, the U.S.-Mexico border has a higher prevalence of T2DM than the U.S. overall. Colonias, small unincorporated towns along the border that may lack infrastructure and/or resources, may be particularly vulnerable to the T2DM disparity. The T2DM disparity among Mexican Americans may persist due to a lack of cultural tailoring of T2DM care to this Hispanic subgroup, thus the care they receive may not be congruent with their sociocultural beliefs, values, and experiences. Little is known about Mexican Americans’ sociocultural beliefs and experiences regarding their T2DM diagnoses, particularly among the Mexican-American women who reside in the colonias near Las Cruces, New Mexico. Therefore, the purpose of this project was to use Kleinman’s Explanatory Model (EM) of Illness as a framework to better understand the beliefs about illness etiology, treatment (including use of herbs), and treatment goals of a small group of Mexican-American women with T2DM living in the colonias near Las Cruces, NM who are patients of the La Clinica de Familia (LCDF) organization in order to serve as a foundation for improving the T2DM care LCDF provides. This project utilized a qualitative descriptive design. Individual participant interviews were used to collect data and data was analyzed using content analysis. Seven women were interviewed. Overall, participants believed or had heard that stress can potentially cause T2DM, the need for insulin indicates more “severe” T2DM, insulin is useful for treating T2DM, and healthy eating and physical activity are important to prevent and manage T2DM, but did not believe or expressed ambivalence about the beliefs that insulin causes complications such as blindness or amputations and that herbs can be used to effectively treat T2DM. Suggestions for areas of potential future research and practice changes within the LCDF organization include: 1) further assessing all aspects of the EMs of T2DM of both the patients of LCDF and of the residents of the colonias near Las Cruces, NM at large, with particular focus on the use of herbs for T2DM treatment; 2) assessing LCDF healthcare providers’ and diabetes educators’ ability and willingness to elicit patients’ EMs; 3) incorporating questions into LCDF’s pre- diabetes self-management education (DSME) questionnaire to elicit the EMs of patients with T2DM; and 4) incorporating a formal way for LCDF healthcare providers and diabetes educators to more regularly assess patients’ DSME and support needs. Gaining a deeper understanding of the EMs, complementary healing practices, and DSME and self-management support needs of Mexican-American women with T2DM living in the colonias near Las Cruces, NM will allow the LCDF organization to combat the T2DM disparity among this population by designing tailored, patient-centered, and culturally-congruent treatment plans and DSME programs.

View more