Resource Type
Collection
Serial/Series Title
Degree Department
Music
55
Department of History
19
Department of Biological Sciences
18
Department of Psychology
13
Department of Behavior Analysis
12
Department of Mechanical and Energy Engineering
12
Department of Materials Science and Engineering
11
College of Music
10
Department of Geography
10
Department of Radio, Television and Film
10
31 More
Degree Discipline
Degree Level
Year
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Measuring the Effect of Alternating In-class with Online Lecture on Student Learning in College Classrooms
Personalized instruction has long been a goal of behavior analysis in the education of typically developing populations, one important element of which is the delivery of lectures in new formats. This study tested feasibility of online lecture delivery by comparing online and in-class delivery of lectures using an adapted alternating treatments design. Each week, the lecture component of a unit of an introductory behavior analysis course was presented either online or in-class, alternating week to week. The alternation was counterbalanced between two sections, where one section saw the lecture for a given unit -online while the other did it in-class, allowing for comparison between lectures of a given unit as well as across units within a section. First attempt quiz scores were measured. No significant difference in the trend of quiz scores between conditions was detected, averaging 73.1% (range, 50.4% to 83.4%) for online and 72.8% (range, 54.8 to 84%) for in-class conditions. This suggests that online lectures are a feasible alternative lecture delivery in this introductory behavior analysis course. This experimental methodology may also be used to test other instructional techniques as well. The ability to place lectures online, opens the door to further, more refined, experimentation with modern …
Date:
August 2013
Creator:
Kellerstedt, Brett G.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Tissue-specific Bioconcentration Factor of the Synthetic Steroid Hormone Medroxyprogesterone Acetate (Mpa) in the Common Carp, Cyprinus Carpia
Due to the wide spread occurrence of medroxyprogesterone acetate (MPA), a pharmaceutical compound, in wastewater effluent and surface waters, the objectives of this work were to determine the tissue specific uptake and bioconcentration factor (BCF) for MPA in common carp. BCFs were experimentally determined for MPA in fish using a 14-day laboratory test whereby carp where exposed to 100 μg/L of MPA for a 7-day period followed by a depuration phase in which fish were maintained in dechlorinated tap water for an additional 7 days. MPA concentrations in muscle, brain, liver and plasma were determined by liquid chromatography/mass spectrometry (LC/MS). The results from the experiment indicate that MPA can accumulate in fish, however, MPA is not considered to be bioaccumulative based on regulatory standards (BCF ≥ 1000). Although MPA has a low BCF value in common carp, this compound may cause reproductive effects in fish at environmentally relevant concentrations.
Date:
August 2013
Creator:
Steele IV, William B.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Lester Walton’s Champion: Black America’s Uneasy Relationship with Jack Johnson
In 1908 Jack Johnson became the first black heavyweight boxing champion of the world. His reign would be rife with controversy, leading to widespread racial violence and draconian government intervention. Lester Walton, theater critic for the New York Age, became obsessed with Johnson; his extensive writing on the boxer powerfully reveals not just Walton’s own struggle with issues of race in America, but sheds light on the difficulties the black community at large faced in trying to make sense of a figure who simultaneously represented hope for the positive change Reconstruction failed to produce and, ironically, also threatened to intensify the hardships of Jim Crow era oppression.
Date:
August 2013
Creator:
McKee, Dave
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Effects of Glyphosate Based Herbicides on Chick Embryo Development
Glyphosate based herbicides are among the most widely used herbicides in the world. The purpose of this study was to determine developmental toxicity of glyphosate, the active ingredient in the common herbicide Roundup, on developing chicken embryos. Few studies have examined toxic effects of glyphosate alone versus the full compound formulations of Roundup, which include adjuvants and surfactants. Adjutants and surfactants are added to aid in solubility and absorption of glyphosate. In this study chicken embryos were exposed at the air cell on embryonic day 6 to 19.8 or 9.9 mg / Kg egg mass of glyphosate in Roundup or glyphosate only. Chickens treated with 19.8 and 9.9 mg / Kg glyphosate in Roundup showed significant reduction in survivability compared to glyphosate alone treatments and controls. On embryonic day 18, embryos were sacrificed for evaluation of developmental toxicity using wet embryo mass, dry embryo mass, and yolk mass as indicators. Morphology measurements were taken on liver mass, heart mass, tibiotarsus length and beak length. Embryos treated with 19.8 mg / Kg glyphosate and 9.9 mg / Kg glyphosate in Roundup showed significant reductions in wet and dry embryo mass and yolk mass. Tibiotarsus length in 9.9 mg / Kg glyphosate …
Date:
August 2013
Creator:
Winnick, Blake Edward
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Issue with Latino Voter Turnout: How Does the Issue of Immigration Affect Latino Voter Turnout?
In this study, I investigate how the issue of immigration affects Latino voter turnout. I hypothesize that U.S. Latino citizens who view immigration as highly important and helpful to the United States will be more likely to turn out to vote in midterm and presidential elections. In addition to a contextual analysis on elections in Arizona and California, I perform a probit regression analysis on survey data from Pew Hispanic's 2004 National Survey of Latinos on Politics and Civic Participation. The results are mixed with respect to the initial expectations. While respondents who view immigration as important and helpful are more likely to turn out than those who view immigration as important and hurtful, the results suggest that respondents who find immigration as unimportant may not be less likely to turn out. Further, there are some differences between Latino subgroups, although these differences are minor. Ultimately, the hypotheses presented in this study find moderate support.
Date:
August 2013
Creator:
Robert, John M.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Spatial Mismatch Between Hiv Infection and Access to Hiv Service Facilities in Texas
Since 2004, the number of people living with HIV (PLWH) has steadily increased by about 5% and currently, the number in Texas is about 86,000. Though the National HIV/AIDS Strategic Plan seeks to ensure “unfettered access to quality healthcare”, barriers to access still exist especially among minority populations. This study examines the relationship between HIV infection rates and the geographic location of HIV service centers with a focus on 4 counties: namely, Dallas, Denton, Harris and Tarrant. The goal is to show whether there is a spatial mismatch between HIV rates and service providers. Are service facilities located in zip codes where they are most needed? Using the vulnerability framework and the Inverse Care Law (ICL), we address the research question using demographic variables (race/ethnicity, sex, poverty, education attainment) and HIV data. Our results show that extreme vulnerable zip codes have high HIV rates and closest proximity to HIV service providers.
Date:
August 2013
Creator:
Aggrey Korsah, Emmanuel
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Remembering and Narrating in Borges’ “Funes the Memorious” and Camus’ the Stranger
In The Stranger, a novel by Albert Camus, and in “Funes the Memorious,” a short story by Jorge Luis Borges, the homodiegetic narrators have a significant effect on the referential aspect of their personal experiences. Chronologically these remembered experiences are positioned before the moment when they are narrated. The act of remembering is thus a form of subsequent narration. In both texts, memory is a project rather than an object because it is recounted and not found. In the sense that it is told, memory is necessarily a creative act and thus not faultless because the story of an experience is not the experience itself. The memories in The Stranger and in “Funes the Memorious” are not reconstituted but narrated. The peculiarity of the two texts lies in the fact that the narrators take an external position when describing their own past, emphasizing the imperfect aspect of the narrators’ memory. With a narratological approach to the texts and a Sartrean interpretation of memory, I study the effects of focalization on the act of remembering. By explaining the relationship between focalization, memory and the narratee, I show that the act of remembering is not a repetition of past events or experiences …
Date:
August 2013
Creator:
Stroud, Carl Eugene
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Exploring Fundamental Principles in the Study of Derived Relational Responding in Pigeons
A persistent challenge for behaviorally-based accounts of learning has been providing an account of learning that occurs in the absence of systematically programmed contingencies of reinforcement. Symmetry, one type of emergent behavior, has been repeatedly demonstrated with humans, but has been considerably more difficult to demonstrate with non-humans. In this study, pigeons were exposed to a go/no-go procedure in which hue stimuli were presented full screen on a touchscreen monitor. Pigeons learned 12 baseline relations in less than 30 days. Traditional measures used to evaluate symmetry indicated that, during tests, three of the four birds responded more to the reverse of relations that were reinforced in training than to the reverse of relations that were not reinforced in training. However, additional analyses of these data suggests that these differences were driven by one of two trial types and that symmetry was only observed for one of the two predicted relations. These data systematically replicate and extend work by Urcuioli and colleagues and point to areas where further research is needed.
Date:
August 2013
Creator:
Hinnenkamp, Jay Evan
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Laser Deposition, Heat-treatment, and Characterization of the Binary Ti-xmn System
The present research seeks to characterization of an additively manufactured and heat-treated Ti-xMn gradient alloy, a binary system that has largely been unexplored. In order to rapidly assess this binary system, compositionally graded Ti-xMn (0<x<15 wt%) specimens were fabricated using the LENS (Laser Engineered Net Shaping) and were subsequently heat-treated and characterized using a wide range of techniques. Microstructural changes with respect to the change in thermal treatments, hardness and chemical composition were observed and will be presented. These include assessments of both continuous cooling, leading to observations of both equilibrium and metastable phases, including the titanium martensites, and to direct aging studies looking for composition regimes that produce highly refined alpha precipitates – a subject of great interest given recent understandings of non-classical nucleation and growth mechanisms. The samples were characterized using SEM, EDS, TEM, and XRD and the properties probed using a Vickers Microhardness tester.
Date:
August 2013
Creator:
Avasarala, Chandana
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Educating American Audiences: Claire Reis and the Development of Modern Music Institutions, 1912-1930
The creation of institutions devoted to promoting and supporting modern music in the United States during the 1920s made it possible for American composers to develop an identity distinct from that of European modernists. These institutions were thus a critical part of the process of modernization that began in the United States during the early decades of the twentieth century. There is substantial scholarship on these musical institutions of modern music, such as the International Composers’ Guild and the League of Composers; but little to no work has been done on the progressive musical institutions of the 1910s, such as the Music League of the People’s Music Institute of New York, which was founded by Claire Reis. This thesis addresses the questions of how and why American musical modernism came to be as it was in the 1920s through an examination of the various stages of Reis’s career. The first chapter is an extensive study of primary source material gathered from the League of Composers/ISCM Records collection at the New York Public Library, which relates to Reis’s work with the PML in the 1910s. The second chapter uses the conclusions of the first chapter to shine new light on an …
Date:
August 2013
Creator:
Freeman, Cole
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Ultimate Ethos: Challenges, Cooptation and Survival During Ultimate’s Adolescence
Ultimate is the fastest growing field sport in America. Created in 1968, forty-five years later the sport was still on the periphery of the mainstream but reached new heights in 2013 – two professional leagues, over 800 college teams and a broadcasting deal with ESPN – and the discussions throughout the sports’ history have never been as relevant. Self-officiation and the Spirit of the Game are the main tenets that make up the ethos of the sport and its community. These unique aspects differentiate Ultimate’s predominate culture from that of mainstream sports culture. This study shows the countercultural ties and survival of the ethos during the adolescent period of Ultimate’s evolution (1987-2010). It examines the progression of the community’s established grassroots culture and the governing body of the sport alongside the influx of young players with mainstream sports attitudes who bolstered certain organizers’ attempts to alter Ultimate in the hopes of gaining “legitimacy” through adding third-party officials, commercialization and corporate sponsorship.
Date:
August 2013
Creator:
Brooks, David
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Ethnogenesis and Captivity: Structuring Transatlantic Difference in the Early Republic, 1776-1823
This study seeks to understand the development of early American ideas of race, religion, and gender as reflected in Indian and Barbary captivity narratives (tales of individuals taken captive by privateers in North Africa) and in plays that take American captives as their subject. Writers of both Indian and Barbary captivity narratives used racial and religious language – references to Indians and North Africans as demonic, physically monstrous, and animal – simultaneously to delineate Native American and North African otherness. The narrative writers reserved particular scorn for the figure of the Renegade – the willful cultural convert who chose to live among the Native Americans or adopt Islam and live among his North African captors. The narratives, too, reflect Early American gendered norms by defining the role of men as heads of household and women’s protectors, and by defining women by their status as dutiful wives and mothers. Furthermore, the narratives carefully treat the figure of the female captive with particular care – resisting implications of captive rape, even while describing graphic scenes of physical torture, and denying the possibility of willful transcultural sexual relationships.
Date:
August 2013
Creator:
Siddiqi, M. Omar
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Sensitivity and Uncertainty Analysis of Occupancy-related Parameters in Energy Modeling of Unt Zero Energy Lab
The study focuses on the sensitivity and uncertainty analysis of occupancy-related parameters using Energyplus modeling method. The model is based on a real building Zero Energy Lab in Discovery Park, at University of North Texas. Four categories of parameters are analyzed: heating/cooling setpoint, lighting, equipment and occupancy. Influence coefficient (IC) is applied in the sensitivity study, in order to compare the impact of individual parameter on the overall building energy consumption. The study is conducted under Texas weather file as well as North Dakota weather file in order to find weather’s influence of sensitivity. Probabilistic collocation method (PCM) is utilized for uncertainty analysis, with an aim of predicting future energy consumption based on history or reference data set. From the study, it is found that cooling setpoint has the largest influence on overall energy consumption in both Texas and North Dakota, and occupancy number has the least influence. The analysis also indicates schedule’s influence on energy consumption. PCM is able to accurately predict future energy consumption with limited calculation, and has great advantage over Monte Carlo Method. The polynomial equations are generated in both 3-order and 6-order, and the 6-order equation is proved to have a better result, which is …
Date:
August 2013
Creator:
Xiong, Guangyuan
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Reading Beyond the Words: How Implementing Esl Strategies During Modified Guided Reading Affects a Deaf Student’s Language Acquisition Process
While Deaf students are not typically classified as English as a second language (ESL) students, the majority of deaf students first become fluent in a signed language, making them ideal candidates for ESL research. This case study has been designed to explore the ways in which one method of ESL reading instruction, known as modified guided reading (MGR), affects the language acquisition process, and resulting reading comprehension level, of a deaf student over eleven weeks. The study documented the student’s language acquisition development both in American Sign Language (ASL) and in English, as well as tracked the student’s growth in reading comprehension, metalinguistic awareness, and visual attention skills. The Accelerated Reader (AR) program, benchmark testing, and daily observations were used to measure growth. Findings of the study suggest that the ESL methods implemented through MGR positively impacted the student’s language acquisition process, reading comprehension level, metalinguistic awareness, and visual attention skills. Results showed an increase in all three of the student’s AR scores as follows: 31% in reading level, 13.1% in number of words read, and 13.2 % in comprehension test scores. Observations and benchmark testing revealed increased metalinguistic knowledge in word, syntactic, and pragmatic awareness. Visual attention skills were …
Date:
August 2013
Creator:
Christian, Laura
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Effect of Dispersed Particles and Branching on the Performance of a Medium Temperature Thermal Energy Storage System
The main objective of my thesis is to develop a numerical model for small-scale thermal energy storage system and to see the effect of dispersing nano-particles and using fractal-like branching heat exchanger in phase change material for our proposed thermal energy storage system. The associated research problems investigated for phase change material (PCM) are the low thermal conductivity and low rate of heat transfer from heat transfer fluid to PCM in thermal energy storage system. In this study an intensive study is carried out to find the best material for thermal storage and later on as a high conductive nano-particle graphite is used to enhance the effective thermal conductivity of the mixed materials. As a thermal storage material molten solar Salt (60% NaNO3+40%KNO3) has been selected, after that detailed numerical modeling of the proposed design has been done using MATLAB algorithm and following the fixed grid enthalpy method. The model is based on the numerical computation of 1-D finite difference method using explicit scheme. The second part of the study is based on enhancing the heat transfer performance by introducing the concept of fractal network or branching heat exchanger. Results from the numerical computation have been utilized for the comparison …
Date:
August 2013
Creator:
Hasib, A. M. M. Golam
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Performance Analysis of Solar Chimney Passive Ventilation System in the Unt Zero Energy Lab
The purpose of this investigation is to find out suitability of the solar chimney natural ventilation system in a Zero Energy Lab located at the University of North Texas campus, to figure out performance of the solar chimney. Reduction in the heating and ventilation and air conditioning energy consumption of the house has been also analyzed. The parameters which are considered for investigation are volumetric flow rate of outlet of chimney, the absorber wall temperature and glass wall temperatures. ANSYS FLUENT 14.0 has been employed for the 3-D modeling of the solar chimney. The dimensions of the solar chimney are 14’2” X 7’4” X 6’11”. The flow inside solar chimney is found to be laminar and the simulation results show that maximum outlet volumetric flow rate of about 0.12m3/s or 432 cfm is possible from chimney. The experimental velocity of chimney was found to be 0.21 m/s. Density Boussinesq approximation is considered for the modeling. Velocity and temperature sensors have been installed at inlet and outlet of the chimney in order to validate the modeling results. It is found that based on simulated volumetric flow rate that cooling load of 9.29 kwh can be saved and fan power of 7.85 …
Date:
August 2013
Creator:
Talele, Suraj H.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Quantitative Assessment of Site Formation at the Dmanisi Archaeological Site, Republic of Georgia
The focus of this thesis was to gather and analyze micromorphological and petrographic data on soils at the archaeological site of Dmanisi in order to better understand the extent to which the deposition and alteration of the sediments has affected the preservation of artifacts and faunal remains. A major goal of this research was to test hypothesis related to why bone material is discovered in some strata and not in others. This research focuses on the application of micromorphology (supplemented with other methods) to the soils through the use of petrographic analysis of thin sections and scanning electron microscopy. These techniques complement previous field analyses by providing a quantitative assessment of individual strata through point counting and chemical mapping. The results of this research support the hypothesis that the sediments are predominantly mafic ashes, while showing that there is very little soil development in the strata. This suggests quick episodic burial in a relatively dry climate, confirming the hypothesis for a short time sequence in the strata. Additionally, differential weathering probably did not play a significant role in the differential abundance of bone remains among the strata at Dmanisi.
Date:
August 2013
Creator:
Crislip, Peter S.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Effects of Training History on Retention and Reacquisition of Stimulus Control
The purpose of this experiment was to study the effects of training history on retention and re-acquisition of stimulus control of previously learned behaviors. In Phase I, two pairs of behaviors were alternately trained. Circle and touch behaviors were trained concurrently until two consecutive errorless sessions were run. Spin and down behaviors were trained together in the same manner. Probe sessions, in which all four cues were presented, were conducted each time a pair of behaviors reached this criterion. Training of one pair did not occur until the other pair had reached criterion and probe sessions were run. Despite achieving the designated criterion during training, stimulus control changed during probes. During probe sessions, errors increased under the cues that were not currently being trained. In most cases, the type of errors emitted for each cue was the same as the behavior that was trained concurrently. The number of training sessions required to reach criterion accuracy was high during the first set of sessions and decreased over the course of the experiment. In Phase II, spin and circle behaviors were trained concurrently. The number of sessions required to reach stimulus control criteria remained low, and the number of errors emitted under …
Date:
August 2013
Creator:
Tucker, Kathryn Lynn
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Gender, Peace and Democracy
In the last several decades there has been immense international emphasis and promotion of gender equality and female participation in the social, economic, and political spheres of society. There has also been an increase in civil conflict recurrence in countries as well as countries transitioning to democracy. This study explores the effect of female participation on peace and democracy. In the first part, I focus on the effect female participation has on decreasing the risk of peace failing in post-civil conflict countries. In many countries, women are marginalized and conflict further marginalizes them. However, I argue that the post-conflict environment allows women to escape this cycle of marginalization and their inclusion and participation is very crucial to sustaining peace. I find that female political and social female decreases the risk of peace failing in post-civil war countries. In the second part, I focus on the effect female participation has on decreasing the risk of authoritarian reversals in countries that have transitioned to and toward democracy. Previous empirical research has focused on women’s role in transitions to democracy, factors that contribute to the survival of democracy, as well as how women’s participation affects the stability country. I argue that women’s social, …
Date:
August 2013
Creator:
Kelly, Eliza G.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Macroinvertebrate Colonization and Assemblages Associated with Aquatic Macrophytes in a Newly Created Urban Floodway Ecosystem, Dallas, Tx
A study of macroinvertebrate colonization and assemblages, including secondary productivity of the familiar bluet damselfly or Enallagma civile Hagen (Odonata: Coenagrionidae), associated with the aquatic macrophytes Heteranthera dubia (Jacq.) MacMill. (water stargrass) and Potamogeton nodosus Poir. (American pondweed) was conducted at the Dallas Floodway Extension Trinity River Project (DFE) Lower Chain of Wetlands (LCOW), Dallas, TX, from September 2010 through November 2011. Macroinvertebrate abundance, taxa richness, Simpson's index of diversity, and Simpson's evenness from the two macrophytes and from three different wetland cells of varying construction completion dates, water sources, and native aquatic vegetation establishment were analyzed along with basic water quality metrics (temperature °C, pH, dissolved oxygen mg/L, and conductivity µs/cm). E. civile nymphs were separated into five developmental classes for secondary productivity estimations between macrophytes and wetland cell types. Mean annual secondary productivity in the DFE LCOW among two macrophytes of E. civile was 1392.90 ash-free dry weight mg/m²/yr, standing stock biomass was 136.77 AFDW mg/m2/yr, cohort production / biomass (P/B) ratio was calculated to be 4.30 / yr and the annual production / biomass (P/B) ratio was 10.18 /yr.
Date:
August 2013
Creator:
Schad, Aaron Neale
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Ocean in Between
Centered on the universal search for home, The Ocean in Between is an autobiographical documentary about my bicultural identity and sense of guilt as a first generation Italian emigrant daughter. As I embark on a journey between Italy and the United States, I attempt to reconcile my American aspirations with my Italian roots. Using observational footage, direct interviews, and narration, this film provides a poetic and intimate look at family relations, love and death, bicultural identity, and sexuality.
Date:
August 2013
Creator:
Masetti, Sara
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Performance Analysis of Two Alternative Hvac Systems for the Unt Zero Energy Lab
This paper covers the simulation and comparison among three different HVAC (heating, ventilation & air conditioning)systems to achieve the goal of finding the most effective HVAC among these three in terms of human comfort, efficiency and cost considering North Texas climate. In the Zero Energy Lab at the University of North Texas, Denton, TX, the HVAC system of the building assembles with geothermal heat source. Here, water to water heat pump with radiant floor and water to air heat pump with air ducts provide heating & cooling of the building. In this paper electricity consumption, comfort, cost & efficiency analysis is done for the existing system using Energy Plus simulation software. Calibration of the simulated data of the existing system is done comparing with the actual data. Actual data is measured using 150 sensors that installed in Zero Energy Lab. After the baseline model calibration, simulation for ground source water to water heat pump, evaporative cooler with baseboard electric heater and water cooled electric chiller with baseboard electric heater (as a conventional system) is shown. Simulation results evaluate the life cycle cost (LCC) for these HVAC systems. The results of the comparison analysis among all the three HVAC systems show …
Date:
August 2013
Creator:
Hasib, Naimee
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Neural Tube Defect, Heart Defect, Oral Cleft and Their Geospatial Associations with Supermarket and Convenience Stores in the City of Dallas, Texas
Birth defects are the leading cause of infant death in the United States. Research has linked poor maternal micronutrient intake to birth defects including neural tube defects, heart defects, and oral clefts. After investigating spatial patterns of these birth defects in the City of Dallas and the neighborhood characteristics within clusters, geospatial access to supermarkets and convenience stores measured by proximity and concentrations are examined as environmental risk factors for nutrition-related birth defects. Spatial clusters of all three nutrition-related birth defects exist in the City of Dallas. Cluster for NTD occurs in vulnerable places with lower income and high minority population specifically Hispanics with no supermarkets. Cluster for heart defects mostly occurs in high income and predominantly white neighborhoods with many supermarkets. Clusters of oral clefts mostly occurs in middle-class income with relatively high minority populations with many convenience stores. For the entire study area, geographical access to supermarkets that include healthy foods are shown to be spatially reachable from most of mothers of infants with nutrition-related birth defects as well as convenience stores that typically include the majority of unhealthy processed foods with very few nutrients. Thus, not only easy geographical access to healthy food vendors but to convenience …
Date:
August 2013
Creator:
Miyakado, Haruna
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Study of Power Generation From a Low-cost Hydrokinetic Energy System
The kinetic energy in river streams, tidal currents, or other artificial water channels has been used as a feasible source of renewable power through different conversion systems. Thus, hydrokinetic energy conversion systems are attracting worldwide interest as another form of distributed alternative energy. Because these systems are still in early stages of development, the basic approaches need significant research. The main challenges are not only to have efficient systems, but also to convert energy more economically so that the cost-benefit analysis drives the growth of this alternative energy form. One way to view this analysis is in terms of the energy conversion efficiency per unit cost. This study presents a detailed assessment of a prototype hydrokinetic energy system along with power output costs. This experimental study was performed using commercial low-cost blades of 20 in diameter inside a tank with water flow speed up to 1.3 m/s. The work was divided into two stages: (a) a fixed-pitch blade configuration, using a radial permanent magnet generator (PMG), and (b) the same hydrokinetic turbine, with a variable-pitch blade and an axial-flux PMG. The results indicate that even though the efficiency of a simple blade configuration is not high, the power coefficient is …
Date:
August 2013
Creator:
Davila Vilchis, Juana Mariel
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library