Baylor University

Permanent URI for this collectionhttps://hdl.handle.net/2249.1/9391

Browse

Now showing 1 - 20 of 1831

Reflections on general relativity from perspectives of black hole physics and Hořava-Lifshitz gravity.
(2015-07-30) Deng, Yanbin 1982-; Cleaver, Gerald B
The physical logic of the Theory of General Relativity is summarized employing differential geometry of surfaces in three dimensional Euclidean space as a visual assistance for understanding. The applications of general relativity in fields as cosmology and black hold physics is summarized. Of the unsolved problem such as cosmology of the very early universe, dark matter and dark energy, black hole singularity and quantization of gravity, some are more fundamental, while some are more about the specific application of general relativity to particular situations. As an application of general relativity, the Hawking temperature and tunneling rate for the Fermion tunnelling process was obtained for a regular black hole which has no singularity inside the body. Hořava-Lifshitz theory, proposed by some physicists as an attempt to fix the quantization problem of general relativity, is employed in the study of a holography problem.
Total electron scattering cross sections of molecules containing H, B, C, N, O, F, Si, P, S, and Cl in the energy range 0.1- 6.0 keV.
(2017-11-06) Gurung, Meera Devi. 1978-; Ariyasinghe, Wickramasinghe M.
The effective atomic total electron scattering cross sections (EATCS) of atomic H, B, C, N, O, F, Si, P, S, and Cl are proposed for 0.1-6.0 keV energies using the existing experimental total electron scattering cross sections (TCS) of simple molecules consisting of these atoms. Based on the EATCS , a simple empirical model depending on the symmetry and geometry of molecule is developed to predict the TCS of H, B, C, N, O, F, Si, P, S, and Cl containing molecules in the energy range 0.1-6.0 keV. The TCS of important biomolecules 2-Butanone Formamide, Trimethylamine, Aniline, Pyrimidine, Anthracene, five nucleic bases (adenine, cytosine, guanine, thymine and uracil) , Phosphoric acid, sugar substitute (Tetrahydrofuran, Furan, Tetrahydropyran, 3-hydroxytetrahydrofuran, D-Glucose, and alpha-D-glucose), and simple amino acids (Glycine, Lysine and L-histidine) in the energy range 0.1-6.0 keV are predicted using the model. The reliability of these predictions are verified by comparing the determined TCS with the available experimental and theoretical cross sections.
Total electron scattering cross sections of molecules containing H, B, C, N, O, F, Si, P, S, and Cl in the energy range 0.1- 6.0 keV.
(2017-11-06) Gurung, Meera Devi. 1978-; Ariyasinghe, Wickramasinghe M.
The effective atomic total electron scattering cross sections (EATCS) of atomic H, B, C, N, O, F, Si, P, S, and Cl are proposed for 0.1-6.0 keV energies using the existing experimental total electron scattering cross sections (TCS) of simple molecules consisting of these atoms. Based on the EATCS , a simple empirical model depending on the symmetry and geometry of molecule is developed to predict the TCS of H, B, C, N, O, F, Si, P, S, and Cl containing molecules in the energy range 0.1-6.0 keV. The TCS of important biomolecules 2-Butanone Formamide, Trimethylamine, Aniline, Pyrimidine, Anthracene, five nucleic bases (adenine, cytosine, guanine, thymine and uracil) , Phosphoric acid, sugar substitute (Tetrahydrofuran, Furan, Tetrahydropyran, 3-hydroxytetrahydrofuran, D-Glucose, and alpha-D-glucose), and simple amino acids (Glycine, Lysine and L-histidine) in the energy range 0.1-6.0 keV are predicted using the model. The reliability of these predictions are verified by comparing the determined TCS with the available experimental and theoretical cross sections.
The chromatin accessibility signature of aging in human blood leukocytes stem from CD8+ T cells.
(2017-07-26) Chung, Cheng-Han. 1982-; Banchereau, Jacques.
Human aging is linked to changes in immune function that contribute to decreased responses to pathogens and increased systemic inflammation. Human aging is also associated with profound epigenetic changes across cell types and tissues. How these changes affect the aging –associated decline of the immune system is unknown. The Assay for Transposase Accessible Chromatin with sequencing technology (ATAC-seq) allowed us to study, at a system biology level, the open chromatin landscapes of human peripheral blood mononuclear cells (PBMCs), monocytes, purified B and T cell subsets from healthy young and healthy elderly individuals. We captured aging-associated epigenomic remodeling in PBMCs consisting of (1) systematic chromatin closing at promoters and enhancers targeting the T cell signaling and development and (2) chromatin opening, mostly at quiescent and repressed sites associated with cytotoxicity. Transcriptome profiling of the same individuals revealed gene expression changes concordant with epigenomic changes. Analysis of naïve and memory CD4+ and CD8+ T cell subsets demonstrated that the epigenomic signature of aging in PBMCs arises mostly from memory CD8+ T cells, indicating that aging differentially affects T cell epigenomes in a subset-specific manner. This study provides the first systems-level description of chromatin accessibility changes associated with immune aging in human PBMCs and T cell subsets. It revealed in PBMCs significant chromatin closing at promoters and enhancers, including at the IL7R locus and the IL-7 signaling pathway. Our study revealed individual-level variability in aging-associated chromatin remodeling and provided a systematic and modular tool for assessing deviations from chronological age. The open chromatin profiling of sorted T cell subsets, concluded that the chromatin “aging signature” captured in PBMCs, mostly stems from memory CD8+ T cells. The combined ATAC-seq/RNA-seq analyses uncovered epigenetic changes poised for expression changes and active noncoding elements (e.g., enhancers), both of which will be essential for understanding the regulatory mechanisms underlying immunosenescence. Nevertheless, ATAC-seq based open chromatin profiling is a straightforward approach to identify functional genomic regulatory regions, master regulators, and gene regulatory networks controlling complex in vivo processes. In our lab, ATAC-seq is utilized to understand the epigenetics differences in different immune cells and diseases.
Linear stability analysis of Mach 10 nitrogen flow over 7-deg half-angle cones.
(2017-08-02) Sakakeeny, Jordan. 1993-; Kuehl, Joseph.
Linear stability theory (LST) analysis was performed on Mach 10 7-degree half-angle straight cones in nitrogen for comparison with experimental results obtained in the Arnold Engineering Development Complex (AEDC) Hypervelocity Wind Tunnel 9. The basic states considered were either generated by STABL at Sandia National Laboratories or with US3D at Baylor University. The LST analysis reproduced the trends of laminar-turbulent transition front moving forward with increasing unit Reynolds number for a sharp nose cone as well as the trend in transition front moving aft as nose bluntness is increased at a constant unit Reynolds number. The strengths of the instabilities were found to be consistent with those measured experimentally. It is hypothesized that the nose bluntness transition trends can be understood by analyzing the thermoacoustic impedance layer.
Three dimensional topology optimization with orthotropic material orientation design for additive manufacturing structures.
(2017-08-02) Jiang, Delin. 1992-; Smith, Douglas E.
Products produced with Additive Manufacturing often have anisotropic microstructures that form material layers are added during processing. Carbon fiber filled polymer deposited in beads with the Fused Filament Fabrication (FFF) process, for example, has been shown to have a highly anisotropic material response. This thesis considers the anisotropic behavior of FFF structures and presents a three dimensional topology optimization method that computes the best anisotropic material distribution and direction for minimum compliance of statically loaded AM structure. The optimization method is applied to single loaded problem, multiple loaded problem, and structures with regions of prescribed solid or void. Results show that printing the structures in different planes yields different minimum compliance of statically loaded AM structure. The opitmization method is applied to single loaded problem, and structures with regions of prescribed solid or void. Results show that printing the structures in different planes yields different minimum compliance, and that the lowest overall compliance is achieved when the applied load vector is parallel to the plan of material orientation. Furthermore, the preferred material orientation generally follows the outer contour of the dense material region for each layer.
Faithful engagement : an examination of the nature and role of values in social policy practice.
(2017-07-21) Sousa, Lori M. 1968-; Yancey, Gaynor.
In social work, a commitment to individual and societal values is foundational, professionally-sanctioned and necessary for culturally sensitive, ethical practice. Values are instrumental in the formation of cultural norms, in the configuration of beliefs systems, and often, they serve as an impetus for policy practice (PP). It is, therefore, surprising that there is a lack of theoretical models that examine and assess the role of values in social PP. The aim of this dissertation is to gain greater insight into this arena. By understanding the nature of values and the role they play in all aspects of social policy, policy practitioners will be better equipped to engage in social PP in a manner that is consistent with ethical, social work practice. This dissertation includes three studies that provide substantial data to suggest that values are a critical, yet overlooked factor in social PP. Based on the findings of these studies, I, as the researcher, constructed the following models to aid policy practitioners in value-sensitive PP: 1) The Religion and Spirituality in Social Policy Practice model (RSSPP)--a framework for conceptualizing the process by which policy practitioners integrate RS in social PP; 2) The Client-Centered Value-Sensitive Social Policy Practice model (VSSPP)--a model used to assist policy practitioners in creating an environment where client values are identified, assessed and employed to guide social policy; and 3) The Individual Policy Frame--a diagram used illustrate significant factors that influence an individual’s values and impact that person’s social policy positions. This dissertation provides tools and suggestions that can be utilized by policy practitioners to engage in client-centered, social PP. Without adequate instruments, social workers often find themselves in an unfamiliar policy arena where their voices and the voices of those they advocate for are marginalized. This dissertation aims to create an empowering environment where social workers are equipped to engage in PP effectively, and where the values of clients and communities are esteemed.
Effect of a restrictive breathing mask on resistance exercise performance in resistance-trained males.
(2017-07-23) Andre, Thomas L. 1987-; Willoughby, Darryn Scott, 1963-
The purpose of this study was to define the impact a RBM has on performance variables, and genes potentially impacted by the stressful nature of the RBM. In a cross-over design, ten participants performed two separate testing sessions, RBM and No Mask, consisting of squat, leg press, and leg extension. Muscle samples were obtained at baseline, 3hr, 6hr, and 24hr post-exercise. Blood samples were obtained to examine cortisol at baseline, 30min, 3hr, 6hr, and 24hr post-exercise. From each muscle sample, glucocorticoid receptor-DNA (GR-DNA) binding and mRNA expression of Atrogin-1, Foxo1, MuRF1, MAFbx, Myostatin, and REDD1 was determined. Two-way repeated-measures analyses of variance (ANOVA) were performed (p ≤ 0.05) with condition and time as main effects. Paired-samples t test was utilized for session rating of perceived exertion (S-RPE). There was a significant decrease in total repetitions during the RBM session (p = .001). A majority of the decrease in repetitions to failure occurred in the squat (p = .030) and in the leg press (p = .001), while no difference was observed in leg extension (p <=.214). There was a significant increase in S-RPE during the RBM session (p = .004). There was a significant increase in pre-stress (p = .007) and post-stress (.010) in the RBM session. No significant difference between mean HR between exercise sessions (p = .083). There was a significant decrease in pulse oximetry during the RBM session (p = .002). No significant interactions between session and time for Atrogin-1, Foxo1, MuRF1, MAFbx, Myostatin, and REDD1. There was no main effect for session for serum cortisol. There was a significant interaction between session and time for GR- DNA binding. For the RBM session, compared to baseline GR-DNA binding was significantly elevated at 3-hr (p = .007), 6-hr (p > .001), and 24-hr (p = .002) post-exercise. The use of a RBM negatively impacted the amount of repetitions completed during an acute session of lower-body resistance training, but failed to affect serum cortisol or alter the expression of proteolytic genes.
Probing interactions among molecules, substrate, and tip using tip-enhanced Raman spectroscopy.
(2017-07-31) Birmingham, Blake. 1991-; Scully, Marlan O. (Marlan Orvil), 1939-
Tip-Enhanced Raman Spectroscopy (TERS) has shown that spatial resolution <1 nm is possible, but is technically challenging and difficult even in Ultra-High Vacuum at low temperatures with plasmonic substrates. Here we demonstrate that in ambient conditions it is possible to obtain Raman signal from isolated molecules on Au and submonolayer molecular islands on bulk MoS2. Analysis of the relative Raman peak ratio and the Raman peak position shift from the spatial TERS mapping show differences in the adsorbates-adsorbates interaction and the adsorbates-substrates interaction on Au and MoS2. TERS tips can influence the shape and diffusion of surfaces and adsorbates. We show the directional growth of Ag island stripes at room temperature via tip-assisted coarsening of hexagonal islands on Ag(111) using scanning tunneling microscope (STM). Tip-assisted island growth is not directly related to the tunneling current, bias voltage, tip composition or atmospheric O2 content but strongly depends on tip morphology.
On the Gram-positive bacterial cell wall.
(2017-07-23) Chang, James D. 1978-; Kim, Sung Joon.
Cell wall is the outermost part of Gram-positive bacteria. It is intricately tied to the bacteria’s response to environmental stimuli and challenges, and its makeup dynamically changes as a part of bacterial adaptation. Peptidoglycan is the biopolymer that composes nearly half of the cell wall, and by studying peptidoglycan valuable insights can be gained into the structure and function of the cell wall. This dissertation examines the chemical compositional changes to the cell wall peptidoglycan in Gram-positive bacteria Enterococcus faecalis and Staphylococcus aureus through solid-state NMR and liquid chromatography-mass spectrometry. These methods analyzed the peptidoglycan without harsh chemical treatments commonly applied to the cell wall that facilitate the use of traditional biochemical methods. Bypassing these treatments allowed for studying various modifications that would have been previously overlooked, and the studies in this dissertation provide peptidoglycan composition analysis at the level of detail where growth conditions and antibiotic challenges to the bacteria could be observed. These studies have revealed that bacteria’s peptidoglycan composition is dynamic, with the bacteria readily altering its cell wall through peptidoglycan as responses to different stimuli and situations. This dissertation presents a representative sampling of experiments undertaken to study the cell wall of Gram-positive bacteria, and it is hoped that they represent different ways of analyzing the cell wall of these medically important pathogens.
Age matters : developmental stage of Zebrafish (Danio rerio) influences bioconcentration, and survival and behavioral photomotor response thresholds.
(2017-08-03) Kristofco, Lauren A. 1989-; Brooks, Bryan W.
Toxicology information for the tens of thousands of compounds in commerce is severely lacking, and with continual introduction of new substances, this global chemical space is only increasing in complexity. Thus, generating data pertinent to legislation, regulation and risk assessment has become paramount. Significant hurdles exist for the production of such data sets as traditional whole organism studies have exorbitant costs, are time intensive, and are low throughput. To meet these goals alternative methods have been developed that shift the focus from a traditional, high dose, apical endpoint, based study design to a higher throughput, systems-biology, based design, however, as this is realized, critical evaluations of the newly introduced methodologies are warranted. Transitioning to high throughput screening (HTS) and predictive methodologies will further require focused efforts to not only identify these assays but also their intrinsic uncertainties. This novel dissertation employed two of the proposed alternative methodologies, probabilistic environmental hazard assessment and the fish embryo toxicity (FET) test, and probed their efficacy with an understudied class of contaminant, antihistamines. In Chapter 2, global hazards of antihistamines in surface waters were assessed with a probabilistic environmental hazard approach (PEHA) to identify global trends in occurrence. Subsequently, the capacity of the FET method to examine mixture interactions with a comparative pharmacology and toxicology approach (Chapter 3), and to extend to include behavioral observations (Chapter 4), was evaluated. Finally, to further elucidate the applicability domain of the FET, Chapter 5 investigated the driver for the age specific shifts in sensitivity evidenced in Chapters 3 and 4. These observations demonstrate the utility of both methods, and underline the importance of method selection and application.
Local wellness policies : key barriers of implementation.
(2017-07-24) Nieft, Jocelyn. 1992-; Funderburk, LesLee K.
Over a decade after passing the Child Nutrition Reauthorization Act of 2004 and mandate of Local Wellness Policies, school districts are still facing barriers within implementing these policies. The success of these policies are based on strength of wording, appropriate resources and support from senior leadership. To determine possible barriers faced by school districts in McLennan County, Texas, a focus group was conducted with members from five independent school districts and members of each district’s school health advisory council and specifically food service managers. Themes derived from this focus group included: ownership of the local wellness policy, resources, and specific barriers for rural schools. These themes are perceived and potential barriers of implementation of local wellness policies.
Abram Ryan, Orestes Brownson, and American Catholics during the Civil War and Reconstruction.
(2017-07-26) Roach, David E. 1993-; Parrish, T. Michael.
This thesis explores how American Catholics reacted to the Civil War and Reconstruction and how those reactions influenced Protestant perceptions of Catholics. Orestes Brownson, a famous Northern convert, polemicist, and supporter of the Union, and Abram Ryan, a Southern poet, priest, and proponent of the Lost Cause, serve as case studies. Analyzing their writing and their reception among Protestant Americans, this thesis demonstrates how religious, racial, political, and even transatlantic developments fueled a Southern and Northern critique of Reconstruction of which Brownson and Ryan were an important part. At the same time, Catholic participation in shared national and sectional reunion and reconciliation also facilitated Catholic's integration into American society. This work focuses on Republican newspapers' praise for Northern Catholic loyalty and Abram Ryan's nationally successful promotion of the Lost Cause. Catholic Civil War Era ideas and actions were emblematic of and crucial to American debates over Catholicism's influence and future.
Psychopathy, yawning, and vigilance.
(2017-07-24) Rundle, Brian Kelly. 1986-; Patton, Jim Harold, 1948-
Psychopathy is characterized by a general antisocial lifestyle with behaviors including being selfish, manipulative, impulsive, fearless, callous, domineering, and particularly lacking in empathy. Contagious yawning in our species has been strongly linked to empathy. One hundred and seventeen students who completed the PPI-R were exposed to a video stimulus of yawns, an in-person yawning stimulus, and a vigilance condition with an in-person yawning stimulus. We found that the vigilance condition extinguished contagious yawning in virtually all participants. We also found that the social-yawning stimulus was not as potent as the video stimulus in evoking yawning. Lastly, we assessed the utility of the Triarchic Psychopathy Measure in this research setting and found that it was not a better measure than the Coldheartedness subscale of the PPI-R in its predictive value of contagious yawning. We provide evidence for a replication of Rundle et al. (2015), a potential negative control for yawning research, and an assessment of an alternative measure to the PPI-R in this research.
Evolution to pollution in Gulf killifish (Fundulus grandis) from Galveston Bay, TX, USA.
(2017-07-27) Oziolor, Elias M. 1990-; Matson, Cole W.
Anthropogenic contamination associated with industrial activity is a widespread and active threat to the stability of organisms. The Houston Ship Channel (HSC) is one example of a heavily impacted environment, where industrial activity has contributed to extreme levels of pollution with various classes of contaminants, such as polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). This dissertation studies the impacts of chronic multi-generational exposure to industrial contamination on the population structure, resistance and demography in a keystone coastal species – Gulf killifish (Fundulus grandis). We have characterized their sensitivity to contaminants in populations from 12 locations across Galveston Bay, as well as the contamination levels at those sites. We found a gradient of resistance that was positively correlated with contaminant concentrations. This resistance was also correlated to a suppression of the aryl hydrocarbon receptor pathway (AHR), as estimated via the activity of a down-stream regulated enzyme – cytochrome P450 1A (CYP1A). To better understand the impacts of this adaptation, we evaluated the cross-resistance and fitness cost of populations to mechanistically and environmentally relevant stressors, but we were unable to confirm any fitness costs. We showed that the heritability of this resistance is biparental and multi-generational, which suggest that this is a genetic trait. Finally, we performed a full genome resequencing of seven populations along this gradient of resistance and discovered that genomic regions under selection in adapted populations included the AHR pathway. To determine if regulatory benchmarks on the compounds driving this adaptation would protect from such events, we performed a meta-analysis of all evolutionary events to contamination with PCBs and PAHs and found several locations, in which populations have adapted at values below regulation. Here we show that Gulf killifish populations have undergone a rapid evolutionary adaptation to a gradient of anthropogenic contaminants in Galveston Bay. In addition, we suggest that evolutionary toxicology studies, as described here, can be informative for regulatory purposes for compounds that may drive population-wide change.
Characterizing hip motion during activities of daily living.
(2017-07-27) Fuller, Carley E. 1993-; Rylander, Jonathan
In the United States alone, 332,000 people received a total hip replacement (THR) each year [1 – need to reattach ref]. Following a total hip arthroplasty, doctors get asked by their patients if they can still do particular activities. There is not enough information out there for them to confidently answer their patients. Additionally, their patients’ questions stem for fear of dislocating. Hip dislocation occurs in between 2% and 11% of patients and is estimated to cost at least $75 million per year [2 from Hip Char protocol]. Therefore, the purpose of this study is to explore activities of daily living (ADLs) that can cause hip dislocation in THA patients so that clinicians can give better instructions to patients and improve post-op rehabilitation strategies following surgery. Our goal is to quantify the movement strategies employed (by healthy persons) to complete these common tasks and identify the motions that can make a person more vulnerable to hip dislocation.
The trombone as signifier in sacred germanic works of the seventeenth and eighteenth centuries
(2017-10-09) Towers, Sha; Elzinga, Harry; Baylor University.
During the seventeenth and eighteenth centuries, Germanic composers recognized and propagated certain rhetorical associations of the trombone. Following a tradition of signification in sacred dramatic works, these composers used the trombone to represent or reinforce religious ideology in a variety of sacred genres. In part, these associations were the consequence of Germanic vernacular translations of the Bible which began in the fifteenth century. Centuries later, musical and literary examples attest to the influence of the psycho-linguistic association between trombone and biblical text. The trombone also shares a rich tradition of symbolic association with its organological ancestor, the trumpet. Numerous iconographic and literary sources from ancient cultures support the importance of symbolism in this instrument family. The associations identified with the trombone's ancestors help to establish the framework out of which the Germanic tradition of the trombone as a signifier emerges centuries later.
The Austin chalk and its petroleum potential : South-Central Texas
(2017-10-09) Thornhill, Stephen Alan; Baylor University. Dept. of Geology.
The Austin Chalk Formation (Upper Cretaceous) consists of uniformly bedded lithologies throughout south-central Texas. The lithologies found within the subsurface are technically wackestones to mudstones. These general textures may be divided into three specific facies: 1) Chalk Marl facies (1,000-7,500 feet), 2) Micritic Limestone (7,500-12,000 feet), and 3) Black calcarous shale facies (12,000 feet). The Chalk has been divided into four specific mappable units: 1) Lower Atco, 2) Upper Atco, 3) Bruceville Chalk Marl, and 4) Futchins Calk. The thickening trends of three units along with the total Austin Chalk interval suggest a uniform period of deposition during the Upper Cretaceous. The sediments deposited during this period were formed along a carbonate ramp-platform depositional environment. Structuring in south-central Texas is primarily faulting and fracturing trends and the homoclinal dip of Chalk to the southeast. The faulting planes are near vertical (65-70 degrees) and strike NE-SW. Fractures are oriented perpendicular to one another and are positioned NE-SW and NW-SE. Production potential of hydrocarbons within the Austin Chalk is controlled mainly by fracture development. Therefore, zones which intersect highly fractured areas are generally good producing wells. Giddings field and various fields within Gonzales County possess the largest amount of hydrocarbon production throughout the study area. Production is greatest in Lee County -- 27 million barrels (bbls) of oil and 75.5 billion cubic feet (BCF) of gas. The cumulative production along the productive chalk trend decreases in a southwesterly direction. This situation implies that fracture development will also show a decrease in this direction. Future development of the Austin Chalk is controlled by economic conditions. However, the best potential zones for future drilling sites may be indicated by "sweet spots" located on cumulative production maps.
Governor control optimization of hydro power plants using hybrid fuzzy logic and PID control.
(2017-07-07) Opado, Frederick Odhiambo. 1987-; Lee, Kwang Y.
Control of hydro power plants has been an issue of concern for researchers; moreover, more emphasis has always been put on governor control which naturally has slower response, but vital in ensuring system stability and elimination of load tracking errors. This thesis studies on ways to use fuzzy logic control (FLC) together with the conventional proportional-integral-derivative (PID) controllers to aid in this process. However, coming up with the inputs, rule base and the outputs, including a number of each of these in the FLC system has always been arbitrary hence proving it difficult for designers to come up with effective parameters for the FLC. This study focuses on ways in which a designer can use fuzzy logic interval partitioning to help come up with sound universe of discourse of variables which determines the effectiveness of the whole control system. This ultimately was put into use and gave us a faster and predictable approach of modelling the control system for hydro plants and gave us satisfactory results.
Numerical simulation of a single fracture with various parameters.
(2017-06-15) Pope, Gina G. 1993-; Dunbar, John A., 1955-
Hydraulic fracturing is the process of enhancing host rock permeability through injection of pressurized fluid in order to obtain oil and natural gas. Typically, microseismicity is used during the fracturing process to monitor the fractures, but this technique fails to describe the degree of fracture connectivity. In this study, the direct current resistivity (DCR) survey method is modeled for fractures with varying lengths, asymmetry, and orientation in order to determine whether DCR can go beyond detection and discriminate fractures based on these parameters. Three different host rock resistivities are used and fracture resistivity is held constant at 0.25 ohm-m. Results indicate that the contrast between host rock and fracture resistivity determines whether a fracture can be detected, and that additional boreholes aid in discerning fractures of different lengths and asymmetric fractures. Additionally, DCR provides the most information about fractures in highly resistive host rocks (>100 ohm-m).

Browse

Recent Submissions