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452 Matching Results
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Computational Modeling of Small Molecules
Computational chemistry lies at the intersection of chemistry, physics, mathematics, and computer science, and can be used to explain the behavior of atoms and molecules, as well as to augment experiment. In this work, computational chemistry methods are used to predict structural and energetic properties of small molecules, i.e. molecules with less than 60 atoms. Different aspects of computational chemistry are examined in this work. The importance of examining the converged orbitals obtained in an electronic structure calculation is explained. The ability to more completely describe the orbital space through the extrapolation of energies obtained at increasing quality of basis set is investigated with the use of the Sapporo-nZP-2012 family of basis set. The correlation consistent Composite Approach (ccCA) is utilized to compute the enthalpies of formation of a set of molecules and the accuracy is compared with the target method, CCSD(T,FC1)/aug-cc-pCV∞Z-DK. Both methodologies are able to produce computed enthalpies of formation that are typically within 1 kcal mol-1 of reliable experiment. This demonstrates that ccCA can be used instead of much more computationally intensive methods (in terms of memory, processors, and time required for a calculation) with the expectation of similar accuracy yet at a reduced computational cost. The …
Date:
December 2015
Creator:
Weber, Rebecca J.
System:
The UNT Digital Library
An Educational Intervention to Promote Self-management and Professional Socialization in Graduate Nurse Anesthesia Students
Traditionally, nurse anesthesia educators have utilized prior academic achievement to predict student success. However, research has indicated that prior academic achievement offers an inadequate assessment of student success in graduate healthcare programs with extensive clinical residencies. The educational literature has identified many non-cognitive factors, such as self-efficacy and locus of control, that may provide a more holistic prediction model of student success. An experimental study with pretest-posttest design and stratified random assignment was conducted to evaluate the effectiveness of an educational intervention to promote self-management, professional socialization, and academic achievement among first semester graduate nurse anesthesia students. Participants (N = 66) were demographically similar to the national graduate nurse anesthesia student body, though Hispanics and younger students were a little over-represented in the sample (56% female, 75.8% White, 15.2% Hispanic, 6% Other, 59% ≤ 30-years-old, 67% ≤ 3 years of ICU). The results showed that most graduate anesthesia students had strong self-management and professional socialization characteristics on admission. The results did not support the effectiveness of this educational intervention. Thus, ceiling effect may have accounted in part for statistically non-significant results regarding self-efficacy (p = .190, ω2 = .03), locus of control (p = .137, ω2 = .04), professional socialization …
Date:
December 2015
Creator:
Maloy, Debra A.
System:
The UNT Digital Library
Identification of Hox Genes Controlling Thrombopoiesis in Zebrafish
Thrombocytes are functional equivalents of mammalian platelets and also possess megakaryocyte features. It has been shown earlier that hox genes play a role in megakaryocyte development. Our earlier microarray analysis showed five hox genes, hoxa10b, hoxb2a, hoxc5a, hoxc11b and hoxd3a, were upregulated in zebrafish thrombocytes. However, there is no comprehensive study of genome wide scan of all the hox genes playing a role in megakaryopoiesis. I first measured the expression levels of each of these hox genes in young and mature thrombocytes and observed that all the above hox genes except hoxc11b were expressed equally in both populations of thrombocytes. hoxc11b was expressed only in young thrombocytes and not in mature thrombocytes. The goals of my study were to comprehensively knockdown hox genes and identify the specific hox genes involved in the development of thrombocytes in zebrafish. However, the existing vivo-morpholino knockdown technology was not capable of performing such genome-wide knockdowns. Therefore, I developed a novel cost- effective knockdown method by designing an antisense oligonucleotides against the target mRNA and piggybacking with standard control morpholino to silence the gene of interest. Also, to perform knockdowns of the hox genes and test for the number of thrombocytes, the available techniques were …
Date:
December 2015
Creator:
Sundaramoorthi, Hemalatha
System:
The UNT Digital Library
Messiaen’s Musical Language: Technique and Theological Symbolism in Les Corps Glorieux, “Combat De La Mort Et De La Vie”
One of the most important ways to understand Olivier Messiaen’s musical language is through the lens of the theological ideas that many of his works convey. He considers expressing his Christian faith to be the primary purpose in his music. Through his idiosyncratic technique, Messiaen gives power and life to his religious music that he combines with his interest in literature, musical analysis, poetic imagery and symbolism, his love for theatre, and his compositional and organ abilities. The abundant studies of Messiaen’s works deal with the intricacies of his musical language, yet most of these studies barely discuss his theological ideas. Nevertheless, technical analysis of his music poses immense challenges, especially in the domains of melody and harmony. Although my approach is unconventional and do not follow any existing system, I base my technical and theological analyses mainly from Messiaen's technique, his commentaries and his references to the Scriptures. The “Combat de la mort et de la vie” is the heart of Les Corps glorieux in both technical and theological aspects. It is an intricate musical artwork where Messiaen demonstrates his melodic and harmonic developments using his idiosyncratic language, and through symbolism portrays the most complex of all drama according …
Date:
December 2015
Creator:
Dellosa, Lerie Grace
System:
The UNT Digital Library
Fractional Calculus and Dynamic Approach to Complexity
Fractional calculus enables the possibility of using real number powers or complex number powers of the differentiation operator. The fundamental connection between fractional calculus and subordination processes is explored and affords a physical interpretation for a fractional trajectory, that being an average over an ensemble of stochastic trajectories. With an ensemble average perspective, the explanation of the behavior of fractional chaotic systems changes dramatically. Before now what has been interpreted as intrinsic friction is actually a form of non-Markovian dissipation that automatically arises from adopting the fractional calculus, is shown to be a manifestation of decorrelations between trajectories. Nonlinear Langevin equation describes the mean field of a finite size complex network at criticality. Critical phenomena and temporal complexity are two very important issues of modern nonlinear dynamics and the link between them found by the author can significantly improve the understanding behavior of dynamical systems at criticality. The subject of temporal complexity addresses the challenging and especially helpful in addressing fundamental physical science issues beyond the limits of reductionism.
Date:
December 2015
Creator:
Beig, Mirza Tanweer Ahmad
System:
The UNT Digital Library
Identification and Characterization of an Arabidopsis thaliana Mutant with Tolerance to N-lauroylethanolamine
N-Acylethanolamines (NAEs) are fatty acid derivatives in plants that negatively influence seedling growth. N-Lauroylethanolamine (NAE 12:0), one type of NAE, inhibits root length, increases radial swelling of root tips and reduces root hair numbers in a dose dependent manner in Arabidopis thaliana L. (ecotype Columbia). A forward genetics approach was employed by screening a population of T-DNA “activation-tagged” developed by the Salk Institute lines for NAE resistance to identify potential genes involved in NAE signaling events in Arabidopsis thaliana L. (ecotype Columbia). Seeds of the activation tagged lines were grown at 0, 25, 30, 50, 75 and 100 µM N-lauroylethanolamime (NAE 12:0). Ten plants which displayed NAE tolerance (NRA) seedling phenotypes, compared with wildtype (Columbia, Col-0) seedlings were identified. I focused on one mutant line, identified as NRA 25, where the tolerance to NAE 12:0 appears to be mediated by a single dominant, nuclear gene. Thermal asymmetric interlaced (TAIL) PCR identified the location of the T-DNA insert as 3.86 kbp upstream of the locus At1g68510. Quantitative PCR indicated that the transcript level corresponding to At1g68510 is upregulated approximately 20 fold in the mutant relative to wildtype. To determine whether the NAE tolerance in NRA 25 is associated with overexpression of …
Date:
December 2015
Creator:
Adhikari, Bikash
System:
The UNT Digital Library
Comparative Analysis and Implementation of High Data Rate Wireless Sensor Network Simulation Frameworks
This thesis focuses on developing a high data rate wireless sensor network framework that could be integrated with hardware prototypes to monitor structural health of buildings. In order to better understand the wireless sensor network architecture and its consideration in structural health monitoring, a detailed literature review on wireless sensor networks has been carried out. Through research, it was found that there are numerous simulation software packages available for wireless sensor network simulation. One suitable software was selected for modelling the framework. Research showed that Matlab/Simulink was the most suitable environment, and as a result, a wireless sensor network framework was designed in Matlab/Simulink. Further, the thesis illustrates modeling of a simple accelerometer sensor, such as those used in wireless sensor networks in Matlab/Simulink using a mathematical description. Finally, the framework operation is demonstrated with 10 nodes, and data integrity is analyzed with cyclic redundancy check and transmission error rate calculations.
Date:
December 2015
Creator:
Laguduva Rajaram, Madhupreetha
System:
The UNT Digital Library
The Role of Injury-related Injustice Perception in Adjustment to Spinal Cord Injury: an Exploratory Analysis
Research has begun to explore the presence and role of health-related injustice perceptions in samples of individuals who experience chronic pain associated with traumatic injury. Existing studies indicate that higher level of injustice perception is associated with poorer physical and psychosocial outcomes. However, to date, few clinical populations have been addressed. The aim of the current study was to explore injustice perceptions in a sample of individuals who have sustained a spinal cord injury (SCI), as research suggests that such individuals are likely to experience cognitive elements characteristic of injustice perception (e.g., perceptions of irreparable loss, blame, and unfairness). The study explored the relationship between participants’ level of perceived injustice and several variables associated with outcomes following SCI (depression, pain, and disability) at initial admission to a rehabilitation unit and at three months following discharge. The Injustice Experience Questionnaire was used to measure injustice perceptions. IEQ was found to significantly contribute to depression and anger at baseline. IEQ significantly contributed to depression, present pain intensity, and anger at follow-up. The implication of these preliminary findings may be beneficial for development of future interventions, as many individuals in the United States experience the lifelong physical and psychological consequences of SCI at …
Date:
December 2015
Creator:
Garner, Ashley Nicole
System:
The UNT Digital Library
Determining the Emissivity of Roofing Samples: Asphalt, Ceramic and Coated Cedar
The goal is to perform heat measurements examine of selected roofing material samples. Those roofing materials are asphalt shingles, ceramics, and cedar. It’s important to understand the concept of heat transfer, which consists of conduction, convection, and radiation. Research work was reviewed on different infrared devices to see which one would be suitable for conducting my experiment. In this experiment, the main focus was on a specific property of radiation. That property is the emissivity, which is the amount of heat a material is able to radiate compared to a blackbody. An infrared measuring device, such as the infrared camera was used to determine the emissivity of each sample by using a measurement formula consisting of certain equations. These equations account for the emissivity, transmittance of heat through the atmosphere and temperatures of the samples, atmosphere and background. The experiment verifies how reasonable the data is compared to values in the emissivity table. A blackbody method such as electrical black tape was applied to help generate the correct data. With this data obtained, the emissivity was examined to understand what factors and parameters affect this property of the materials. This experiment was conducted using a suitable heat source to heat …
Date:
December 2015
Creator:
Adesanya, Oludamilola
System:
The UNT Digital Library
Direct Strength Method for Web Crippling of Cold-formed Steel C and Z Sections Subjected to Interior One Flange Loading and End One Flange Loading
The main objective of this research is to extend the “Direct strength method” for determining the web crippling strength of cold-formed steel C and Z sections subjected to End one flange loading and Interior one flange loading conditions. Direct strength method is applied for designing the columns and beams earlier. The existing specifications equation for calculating the web crippling strength of cold-formed steels designed by American Institute of Iron and Steel is very old method and it is based on the extensive experimental investigations conducted at different universities. Calculating the web crippling strength of cold-formed steels using direct strength method is a new technique. In the present research the web crippling strength of cold-formed steels were calculated using Direct Strength Method. The experimental data is collected from the tests that were conducted at different universities. The critical buckling strength of the members were calculated using Abaqus. Microsoft excel is used to generate the equations. The safety and resistance factors for the designed equations were calculated using “Load and resistance factor design” and “Allowable strength design” from North American Cold-Formed Steel Specification, 2012 edition book.
Date:
December 2015
Creator:
Dara, Martin Luther
System:
The UNT Digital Library
Lone Star Insanity: Efforts to Treat the Mentally Ill in Texas, 1861-1929
During the mid-nineteenth century, the citizens of Texas were forced to keep their mentally disturbed family members at home which caused stress on the caregivers and the further debilitation of the afflicted. To remedy this situation, mental health experts and Texas politicians began to create a system of healing known as state asylums. The purpose of this study is to determine how Texas mental health care came into being, the research and theories behind the prevention and treatment programs that asylum physicians employed to overcome mental illness, in addition to the victories and shortcomings of the system. Through this work, it will be shown that during the 1850s until the 1920s institutions faced difficulty in achieving success from many adverse conditions including, but not limited to, overcrowding, large geographical conditions, poor health practices, faulty construction, insufficient funding, ineffective prevention and treatment methods, disorganization, cases of patient abuse, incompetent employees, prejudice, and legal improprieties. As a result, by 1930, these asylums were merely places to detain the mentally ill in order to rid them from society. This thesis will also confirm that while both Texas politicians and mental health experts desired to address and overcome mental illness in Texas, they were …
Date:
December 2015
Creator:
Boyd, Dalton T.
System:
The UNT Digital Library
Spatially Explicit Modeling of West Nile Virus Risk Using Environmental Data
West Nile virus (WNV) is an emerging infectious disease that has widespread implications for public health practitioners across the world. Within a few years of its arrival in the United States the virus had spread across the North American continent. This research focuses on the development of a spatially explicit GIS-based predictive epidemiological model based on suitable environmental factors. We examined eleven commonly mapped environmental factors using both ordinary least squares regression (OLS) and geographically weighted regression (GWR). The GWR model was utilized to ascertain the impact of environmental factors on WNV risk patterns without the confounding effects of spatial non-stationarity that exist between place and health. It identifies the important underlying environmental factors related to suitable mosquito habitat conditions to make meaningful and spatially explicit predictions. Our model represents a multi-criteria decision analysis approach to create disease risk maps under data sparse situations. The best fitting model with an adjusted R2 of 0.71 revealed a strong association between WNV infection risk and a subset of environmental risk factors including road density, stream density, and land surface temperature. This research also postulates that understanding the underlying place characteristics and population composition for the occurrence of WNV infection is important for …
Date:
December 2015
Creator:
Kala, Abhishek K.
System:
The UNT Digital Library
The Practice of ‘Adoptive’ Transcription in Selected Works for Clarinet by Eugène Bozza
Eugène Bozza is a three-time winner of the Premier Prix from the Paris Conservatory, in violin, conducting, and composition divisions. He earned his reputation as a master composer of wind music, and contributed a great amount of repertoire to the woodwind family. This document contains a short biography of Eugène Bozza’s life, including his student years and his career as a composer. The purpose of this study is to provide information of how Bozza transferred, adopted and remade his own music among his wind compositions. This document shows that Bozza’s methods of musical adoption warrant a close examination in order to offer greater insight into the mind of a masterful composer. Discussion of Bozza’s compositions includes Aria (1936), Fantasie Italienne (1939), Pulcinella (1944), Concerto (1952), Idylle (1959), Caprice-Improvisation (1963), Épithalame (1971), Suite (1974), Trois Mouvements for Flute and Clarinet (1974), Graphismes for Clarinet Solo (1975), 14 Études de Mécanisme (1948), 12 Études (1953), 11 Études sur des Modes Karnatiques (1972), and Contrastes III for Clarinet and Bassoon (1977).
Date:
December 2015
Creator:
Liu, Hsing-Fang
System:
The UNT Digital Library
Sensitivity, Inspiration, and Rational Aesthetics: Experiencing Music in the North German Enlightenment
This dissertation examines pre-Kantian rational philosophy and the development of the discipline of aesthetics in the North German Enlightenment. With emphasis on the historical conception of the physiological and psychological experience of music, this project determines the function of music both privately and socially in the eighteenth century. As a result, I identify the era of rational aesthetics (ca.1750-1800) as a music-historical period unified by the aesthetic function and metaphysical experience of music, which inform the underlying motivation for musical styles, genres, and means of expression, leading to a more meaningful and compelling historical periodization. The philosophy of Alexander Baumgarten, Johann Georg Sulzer, and others enable definitions of the experience of beautiful objects and those concepts related to music composition, listening, and taste, and determine how rational aesthetics impacted the practice, function, and ultimately the prevailing style of music in the era. The construction, style, and performance means of the free fantasia, the most personal and expressive genre of the era, identify its function as the private act of solitude, or a musical meditation. An examination of pleasure societies establishes the role of music in performance and discussion in both social gatherings and learned musical clubs for conveying the morally …
Date:
December 2015
Creator:
Fick, Kimary E.
System:
The UNT Digital Library
Searching for a Savior
This collection of essays includes a preference that investigates the role and importance of setting and character in a nonfiction narrative. The preface assesses the writings of four great authors, examining how each author use setting and characterization to further the purpose of their story. This collection focuses on four different issues that the author has wrestled with for two decades. While “Desperado” is an investigation into the problems within her own family, “Being Black Me” highlights the authors struggle against the racial inequality her hometown. “Voices In The Dark”, the author analyze how the abuse she suffered as a child has influenced her life and contributed to a drinking problem that is explored in a later essay “Alors On Danse”.
Date:
December 2015
Creator:
Batch, Julia
System:
The UNT Digital Library
Mobile Learning: Factors That Influence University Students’ Intention to Use Smartphones
This study investigated the factors that influence university students’ intention to use a smartphone. The study proposed and validated a research model based on the technology acceptance model (TAM). The TAM was modified and extended with four new constructs: social norms, perceived enjoyment, perceived value and ease of access. The constructs for the instrument of the study were adapted from previous related studies which had validated the instruments. Data were collected from 110 participants via a survey. The collected data were analyzed using hierarchical multiple-regression using the statistical package for social sciences (SPSS version 22.0). The model demonstrated a good fit where six independent variables together contributed 56.2% of the variance to the outcome or prediction. The results of the analysis were used to test a set of research hypotheses and to answer research questions. The following independent variables were found to be significant in determining university students’ intention to use mobile devices: perceived usefulness, social norms, perceived enjoyment, perceived value and ease of access. The control variables gender and degree level and the independent variable ease of use were not significant predictors. The results of this study may be useful to understand which factors are more important to the …
Date:
December 2015
Creator:
Hossain, Akhlaq
System:
The UNT Digital Library
School and Community Partnerships: Effect on At-risk Elementary Student Populations
The purpose of this study was to investigate the current practices of school and community partnerships in five North Texas elementary schools. In addition, the study focused on the influence community partnerships have on at-risk students based on at-risk indicators data. The literature revealed that when schools, parents, and families work together, students tend to earn higher grades, attend school more regularly, stay in school longer, and enrolled in coursework beyond high school. The target population included approximately 350 administrators, teachers, and paraprofessionals from five North Texas elementary schools. Also included were the respective partners from each of the five elementary schools. This research included online survey instrument and data were gathered and analyzed through a combination of statistical procedures and descriptive and inferential statistics. The results may provide other schools with a profile of school and community partnerships that can be implemented as a method to help their at-risk student populations. Findings included a descriptive analysis of factors that contributed to the success of community engagement efforts as well as those factors that limited those efforts. A secondary purpose of this study was of continuous improvement in developing these approaches through a goal-setting approach. Schools included in the study …
Date:
December 2015
Creator:
Tucker, Linda Cavazos
System:
The UNT Digital Library
Form in Popular Song, 1990-2009
Through an examination of 402 songs that charted in the top 20 of the Billboard year-end charts between the years 1990 and 2009, this dissertation builds upon previous research in form of popular song by addressing the following questions: 1) How might formal sections be identified through melody, harmony, rhythm, instrumentation, and text? 2) How do these sections function and relate to one another and to the song as a whole? 3) How do these sections, and the resulting formal structures, relate to what has been described by previous theorists as normative? 4) What new norms and trends can be observed in popular song forms since 1990? Although many popular songs since 1990 do follow well-established forms, some songwriters and producers change and vary these forms. AAA strophic form, AABA form, Verse-Chorus form, Verse-Chorus with Prechorus and/or Postchorus sections, Verse-Chorus-Bridge form, “Other, with a Chorus” and “Other, without a Chorus” forms are addressed. An increasing number of the songs in each of the above listed forms are based on a repeating harmonic progression or no harmonic progression at all. In such songs, the traditional method of identifying sections and section-functions through harmonic analysis is less useful as an analytical tool, …
Date:
December 2015
Creator:
Ensign, Jeffrey S.
System:
The UNT Digital Library
Exploring the Effectiveness of Curriculum Provided Through Transmedia Books for Increasing Students’ Knowledge and Interest in Science
Transmedia books are new and emerging technologies which are beginning to be used in current classrooms. Transmedia books are a traditional printed book that uses multiple media though the use of Quick Response (QR) codes and augmented reality (AR) triggers to access web-based technology. Using the transmedia book Skills That Engage Me students in kindergarten through second grade engage in curriculum designed to introduce science skills and careers. Using the modified Draw-a-Scientist Test (mDAST), observations and interviews, researchers analyzed pre and post data to describe changes students have about science and scientists. Future study may include the development and validation of a new instrument, Draw a Science Student, and examining the mDAST checklist with the intention of updating the parameters of what is considered positive and negative in relationship with work a scientist conducts.
Date:
December 2015
Creator:
Ponners, Pamela Jones
System:
The UNT Digital Library
No Quarter: the Story of the New Orleans Greys
The purpose of this thesis document is to explain the process of making the documentary film, No Quarter: The Story of the New Orleans Greys. The document is organized by having the prospectus and the film proposal at the beginning, with the body describing how the film was made based on the prospectus. The purpose of the film is to tell the history of a unit of volunteers in the Texas Revolution, the New Orleans Greys. The document describes the methods used to make the film and how it will be distributed to the intended audience. As the thesis explains, the film changed slightly from the prospectus, however the resulting film was successful in telling the history of the little-known New Orleans Greys.
Date:
December 2015
Creator:
Barnes, Travis S.
System:
The UNT Digital Library
Traditional Bullying and Cyberbullying in Korean Children and Youth with Emotional and Behavioral Disabilities: Examination of Contributing Factors
Children and Adolescents with emotional and behavioral disabilities (EBD) are often involved in aggression, acting out, bullying, violence, substance abuse, and juvenile crime. However, the limited Korean studies have focused primarily on bullying of students with developmental disabilities or intellectual disabilities. Therefore, the current study aimed to explore contributing factors to traditional bullying and cyberbullying in Korean children and adolescents with EBD. The current study surveyed 112 students with EBD between ages of 10 and 15 and their parents (guardians). The results revealed that internalizing problem behaviors including anxious/depression, withdrawal/depression, and somatic problems significantly affected traditional bullying victimization of Korean students with EBD. The peer support was a significant factor affecting cyberbullying victimization. Furthermore, the maternal psychological control was a meaningful factor affecting perpetration at school and in cyber world. Based on the findings, the present study described implications regarding prevention and intervention programs for addressing traditional bullying and cyberbullying victimization and perpetration.
Date:
August 2015
Creator:
Baek, Ji Eun
System:
The UNT Digital Library
Urban Sustainability and the Extinction of Experience: Acknowledging Drivers of Biocultural Loss for Socio-ecological Well-being
In this dissertation I address urban sustainability with a focus on loss of cultural heritage and ecological knowledge by expanding the concept “extinction of experience” (EoE). Conceptualized by conservationist Robert Michael Pyle, EoE is the loss of nature experiences leading to apathy towards biodiversity and degradation of the common habitat. I expand upon Pyle’s formulation of the concept by considering the EoE cycle as an indirect driver that amplifies biodiversity losses. Additionally, I introduce the analysis of interrelated losses of biological and cultural diversity in relation to EoE. With a biocultural approach I discuss that EoE is tied to the infrastructural inertia within the global urban economy. I propose that addressing the EoE cycle is critical in that as a complex and multi-faceted process, it cements threats to biological and cultural diversity as permanent fixtures within society by obscuring their significance in light of economic development. This cycle remains a hidden problematic in that it perpetuates the environmental crisis while making such losses invisible within day-to-day lifestyle habits, constructing an emerging urban culture within the global economy that is ignorant of ecological processes and sustainability requirements. I frame the implications of EoE with an analysis of the newly proposed revisions …
Date:
December 2015
Creator:
Poole, Alexandria K.
System:
The UNT Digital Library
Environmental Modulation of the Onset of Air-breathing of the Siamese Fighting Fish and the Blue Gourami
This study determined the effect of hypoxia on air-breathing onset and physiological and morphological characters in larvae of the air breathing fishes Trichopodus trichopterus and Betta splendens. Larvae were exposed intermittently (12/12 h daily) to 20, 17, and 14 kPa of PO2 from 1 to 40 days post-fertilization. Survival, onset of air breathing, wet body mass, O2, Pcrit were measured every 5 dpf. Hypoxia advanced by 4 days, and delayed by 9 days, the onset of air breathing in Betta and Trichopodus, respectively. Hypoxia increased larval body length, wet mass, and labyrinth organ respiratory surface of Betta, but did not affect these factors in Trichopodus. Hypoxic exposure increased O2 by 50-100% at each day throughout larval development in Betta, but had no effect on larval Trichopodus. Hypoxia decreased Pcrit in Betta by 37%, but increased Pcrit in Trichopodus by 70%. Larval Betta reared in hypoxia showed a modified heart rate:opercular rate ratio (3:1 to 2:1), but these changes did not occur in Trichopodus. Compared to Betta, the blood of Trichopodus had a higher P50 and much smaller Bohr and Root effects. These interspecific differences are likely due to ecophysiological differences: Betta is a non- obligatory air-breather after 36 dpf with …
Date:
December 2015
Creator:
Mendez Sanchez, Jose Fernando
System:
The UNT Digital Library
Anisotropic Nature of Radially Strained Metal Tubes
Metal pipes are sometimes swaged by a metal cone to enlarge them, which increases the strain in the material. The amount of strain is important because it affects the burst and collapse strength. Burst strength is the amount of internal pressure that a pipe can withstand before failure, while collapse strength is the amount of external pressure that a pipe can withstand before failure. If the burst or collapse strengths are exceeded, the pipe may fracture, causing critical failure. Such an event could cost the owners and their customers millions of dollars in clean up, repair, and lost time, in addition to the potential environmental damage. Therefore, a reliable way of estimating the burst and collapse strength of strained pipe is desired and valuable. The sponsor currently rates strained pipes using the properties of raw steel, because those properties are easily measured (for example, yield strength). In the past, the engineers assumed that the metal would be work-hardened when swaged, so that yield strength would increase. However, swaging introduces anisotropic strain, which may decrease the yield strength. This study measured the yield strength of strained material in the transverse and axial direction and compared them to raw material, to determine …
Date:
December 2015
Creator:
Strickland, Julie N.
System:
The UNT Digital Library