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Mechanical Characterization of A2 and D2 Tool Steels By Nanoindentation (open access)

Mechanical Characterization of A2 and D2 Tool Steels By Nanoindentation

Nanoindentation technique was used to investigate the surface properties of A2 and D2 tool steel subjected to different heat treatments. the mechanical characteristics of these two easily available tool steels were studied based on microstructural images obtained from SEM, the grain growth after heat treatment using X-ray diffraction method and nanoindentation technique. the investigation showed that a single nanoindentation result can explain how heat treatment influences reliability and failure in A2 and D2 tool steels. in this work, the causes and effects of these variations were studied to explain how they influence reliability and failure in A2 and D2 tool steel. Finally, a cube-corner indenter tip was used to determine the fracture toughness of silicon wafer. the emphasis of this research is on how nanoindentation technique is more extensive in material characterization.
Date: May 2012
Creator: Okafor, Uzochukwu Chimezie
System: The UNT Digital Library
Bearing Strength of Cold Formed Steel Bolted Connections in Trusses (open access)

Bearing Strength of Cold Formed Steel Bolted Connections in Trusses

The existing design provision in North American Specification for Cold- Formed Steel Structural Member (AISI S100) for the bearing strength of bolted connections were developed from tests on bolted connected sheets which were restrained by bolt nut and head with or without washers. However, in the cold-formed assemblies, particularly in trusses, the single bolt goes through both sides of the connected sections, making the connected sheets on each side unrestrained. the warping of the unrestrained sheet may reduce the bearing strength of the bolted connection. This research investigates the behavior and strength of bearing failure in bolted connections in cold-formed steel trusses. Tensile tests were conducted on trusses connections with various material thicknesses. It was found that the AISI S100 works well for thick connections but provides unconservative predictions for thin materials. Based on the experimental results, a modified bearing strength method is proposed for calculating the bearing strength of bolted truss connections. the proposed method can be used for any cold-formed steel connections with unrestrained sheet.
Date: May 2012
Creator: Panyanouvong, Mark
System: The UNT Digital Library
Investigating Realistic Scenarios of Biodiversity Loss on Ecosystem Functioning: Extirpation of Rare Species and Food Web Collapse in Tropical Floodplain Lagoons (open access)

Investigating Realistic Scenarios of Biodiversity Loss on Ecosystem Functioning: Extirpation of Rare Species and Food Web Collapse in Tropical Floodplain Lagoons

This thesis investigates the influence of nonrandom species loss on the structure and functioning of trophic floodplain lagoons. Two experiments were conducted based on different realistic scenarios of biodiversity loss using multitrophic fish assemblages derived from long-term survey data. Loss of fish diversity influenced overall ecosystem multifunctionality of these lagoons through complex multitrophic interactions throughout the aquatic food web. These results indicate that biodiversity loss from diverse multitrophic ecosystems can influence ecosystem structure and function and likely deviate from simplified food chain dynamics or patterns that emerged from single trophic level studies.
Date: May 2012
Creator: Pendleton, Richard McCall
System: The UNT Digital Library
Social Networking: the Benefits of Twitter for Music Fans and Consumers (open access)

Social Networking: the Benefits of Twitter for Music Fans and Consumers

Due to the evolution of new media technologies, social networking websites have become major avenues for online media consumption. Twitter is one of many proven beneficial for online users. It is utilized for many different reasons, one of which includes music. It is then necessary to know how beneficial Twitter is for music fans and consumers. This study attempts to analyze the benefits of Twitter for music fans and consumers. Using an online survey, different gratification items are measured. Results reveal that some music fans and consumers do use Twitter for music purposes and that there is a statistically significant difference in terms of gratifications between those who use Twitter for music purposes and those who do not.
Date: May 2012
Creator: Perrilliat, Jessica A.
System: The UNT Digital Library
Evaluation of Fine Particulate Matter Pollution Sources Affecting Dallas, Texas (open access)

Evaluation of Fine Particulate Matter Pollution Sources Affecting Dallas, Texas

Dallas is the third largest growing industrialized city in the state of Texas. the prevailing air quality here is highly influenced by the industrialization and particulate matter 2.5µm (PM2.5) has been found to be one of the main pollutants in this region. Exposure to PM2.5 in elevated levels could cause respiratory problems and other health issues, some of which could be fatal. the current study dealt with the quantification and analysis of the sources of emission of PM2.5 and an emission inventory for PM2.5 was assessed. 24-hour average samples of PM2.5 were collected at two monitoring sites under the Texas Commission on Environmental Quality (TCEQ) in Dallas, Dallas convention Centre (CAMS 312) and Dallas Hinton sites (CAMS 60). the data was collected from January 2003 to December 2009 and by using two positive matrix models PMF 2 and EPA PMF the PM2.5 source were identified. 9 sources were identified from CAMS 312 of which secondary sulfate (31% by PMF2 and 26% by EPA PMF) was found to be one of the major sources. Data from CAMS 60 enabled the identification of 8 sources by PMF2 and 9 by EPA PMF. These data also confirmed secondary sulfate (35% by PMF2 and …
Date: May 2012
Creator: Puthenparampil Koruth, Joseph
System: The UNT Digital Library
The Portuguese Expeditionary Corps in World War I: From Inception to Destruction, 1914-1918 (open access)

The Portuguese Expeditionary Corps in World War I: From Inception to Destruction, 1914-1918

The Portuguese Expeditionary Force fought in the trenches of northern France from April 1917 to April 1918. on 9 April 1918 the sledgehammer blow of Operation Georgette fell upon the exhausted Portuguese troops. British accounts of the Portuguese Corps’ participation in combat on the Western Front are terse. Many are dismissive. in fact, Portuguese units experienced heavy combat and successfully held their ground against all attacks. Regarding Georgette, the standard British narrative holds that most of the Portuguese soldiers threw their weapons aside and ran. the account is incontrovertibly false. Most of the Portuguese combat troops held their ground against the German assault. This thesis details the history of the Portuguese Expeditionary Force.
Date: May 2012
Creator: Pyles, Jesse
System: The UNT Digital Library
The Natural Learning Process and Its Implications for Trombone Pedagogy (open access)

The Natural Learning Process and Its Implications for Trombone Pedagogy

This thesis considers the natural learning process as defined by Timothy Gallwey and Daniel Kohut. This learning theory is examined and applied to trombone pedagogy while also considering physiological attributes to trombone performance. a brief synopsis of the history and lineage of the trombone is considered in order to understand the current setting of the trombone medium.
Date: May 2012
Creator: Reider, Shane Robert
System: The UNT Digital Library
Comparing the 2010 and 2011 Appic Match: Applicant Characteristics and Unmatched Applicant Distress (open access)

Comparing the 2010 and 2011 Appic Match: Applicant Characteristics and Unmatched Applicant Distress

The internship is one of the most important components of doctoral training in professional psychology. Given the serious problem of the internship imbalance, applicant and program characteristics that constitute a good “fit” with internship training programs have become of greater interest as securing an internship becomes a more competitive process. This study surveyed internship applicants from programs part of the Council of University Directors of Clinical Psychology (CUDCP), before and after the 2010 and 2011 match days. Number of interview offers was found to be the factor most consistently associated with successfully matching, and several other applicant characteristics salient to matching and obtaining interview offers were identified, including applicant personality. Additionally, personal accounts, but not empirical evidence, of going unmatched have attested to the psychological distress associated with this event. in the current study, while going unmatched was not found to be equitable to a traumatic stressor, evidence was found to support significant decrease in subjective well-being with respect to immediate distress. Findings are discussed in terms of the predictability of and implications for the match process and internship imbalance, and recommendations are made for future research directions.
Date: May 2012
Creator: Hogan, Lindsey R.
System: The UNT Digital Library
A Global Stochastic Modeling Framework to Simulate and Visualize Epidemics (open access)

A Global Stochastic Modeling Framework to Simulate and Visualize Epidemics

Epidemics have caused major human and monetary losses through the course of human civilization. It is very important that epidemiologists and public health personnel are prepared to handle an impending infectious disease outbreak. the ever-changing demographics, evolving infrastructural resources of geographic regions, emerging and re-emerging diseases, compel the use of simulation to predict disease dynamics. By the means of simulation, public health personnel and epidemiologists can predict the disease dynamics, population groups at risk and their geographic locations beforehand, so that they are prepared to respond in case of an epidemic outbreak. As a consequence of the large numbers of individuals and inter-personal interactions involved in simulating infectious disease spread in a region such as a county, sizeable amounts of data may be produced that have to be analyzed. Methods to visualize this data would be effective in facilitating people from diverse disciplines understand and analyze the simulation. This thesis proposes a framework to simulate and visualize the spread of an infectious disease in a population of a region such as a county. As real-world populations have a non-homogeneous demographic and spatial distribution, this framework models the spread of an infectious disease based on population of and geographic distance between …
Date: May 2012
Creator: Indrakanti, Saratchandra
System: The UNT Digital Library
Cuff-less Blood Pressure Measurement Using a Smart Phone (open access)

Cuff-less Blood Pressure Measurement Using a Smart Phone

Blood pressure is vital sign information that physicians often need as preliminary data for immediate intervention during emergency situations or for regular monitoring of people with cardiovascular diseases. Despite the availability of portable blood pressure meters in the market, they are not regularly carried by people, creating a need for an ultra-portable measurement platform or device that can be easily carried and used at all times. One such device is the smartphone which, according to comScore survey is used by 26.2% of the US adult population. the mass production of these phones with built-in sensors and high computation power has created numerous possibilities for application development in different domains including biomedical. Motivated by this capability and their extensive usage, this thesis focuses on developing a blood pressure measurement platform on smartphones. Specifically, I developed a blood pressure measurement system on a smart phone using the built-in camera and a customized external microphone. the system consists of first obtaining heart beats using the microphone and finger pulse with the camera, and finally calculating the blood pressure using the recorded data. I developed techniques for finding the best location for obtaining the data, making the system usable by all categories of people. …
Date: May 2012
Creator: Jonnada, Srikanth
System: The UNT Digital Library
Teaching Past the Test: a Pedagogy of Critical Pragmatism (open access)

Teaching Past the Test: a Pedagogy of Critical Pragmatism

Existent scholarship in communication studies has failed to adequately address the particular pedagogical context of current public secondary education within the United States. While communication studies has produced a great deal of scholarship centered within the framework of critical pedagogy, these efforts fail to offer public high school teachers in the U.S. a tenable alternative to standardized constructs of educational communication. This thesis addresses the need for a workable, critical pedagogy in this particular educational context as a specific question of educational communication. a theorization of pedagogical action drawing from critical pedagogy, pragmatism, and communication studies termed “critical pragmatism” is offered as an effective, critical counter point to current neoliberal classroom practices in U.S. public secondary schools.
Date: May 2012
Creator: Jordan, Jason
System: The UNT Digital Library
An Analysis of the Correspondence Between the Measures Collected by an Autism Treatment Center and its Stated Mission Goals (open access)

An Analysis of the Correspondence Between the Measures Collected by an Autism Treatment Center and its Stated Mission Goals

This study was a program evaluation for an autism treatment center for the period of April 2008 through August 2011. the study extended previous evaluations of the autism treatment center. the purpose of this evaluation was to determine the degree to which the center’s measures corresponded with its stated mission goals. a number of data sources were reviewed including client records of demographic and outcome information. Findings suggest the center maintained records that allow for the evaluation of most of its mission’s goals. There were, however, difficulties with data collection, storage, and retrieval. the present program evaluation found that missing information and lack of follow-up information hindered efforts toward mission evaluation.
Date: May 2012
Creator: Kowalchuk, Holly M.
System: The UNT Digital Library
Alternative Complementation in Partially Schematic Constructions:  a Quantitative Corpus-based Examination of COME to V2 and GET to V2 (open access)

Alternative Complementation in Partially Schematic Constructions: a Quantitative Corpus-based Examination of COME to V2 and GET to V2

This paper examines two English polyverbal constructions, COME to V2 and GET to V2, as exemplified in Examples 1 and 2, respectively. (1) the senator came to know thousands of his constituents (2) Little Johnny got to eat ice cream after every little league game. Previous studies considered these types of constructions (though come and get as used here have not been sufficiently studied) as belonging to a special class of complement constructions, in which the infinitive is regarded as instantiating a separate, subordinate predication from that of the “matrix” or leftward finite verb. These constructions, however, exhibit systematic deviation from the various criteria proposed in previous research. This study uses the American National Corpus to investigate the statistical propensities of the target phenomena via lexico-syntactic (collostructional analysis) and morpho-syntactic (binary logistic regression) features, as captured through the lens of construction grammar.
Date: May 2012
Creator: Lester, Nicholas A.
System: The UNT Digital Library
Nominal Shear Strength of Cold-formed Steel Shear Walls Using Osb Sheathing (open access)

Nominal Shear Strength of Cold-formed Steel Shear Walls Using Osb Sheathing

In the cold-formed steel construction, the oriented strand board is a common material for shear wall sheathing. an OSB is made by using wood chips as raw materials that undergo high temperature pressing to create a multi-larger structure material. Due to the OSB having a high strength in shear, it is an important material used in the construction field. the thesis is trying to verify published nominal shear strength in AISI-213-07 in the first part. This objective has two parts: the first part is to verify nominal shear strength (Rn) for wind and other in-plane loads for shear wall. the second part is to verify nominal shear strength (Rn) for seismic and other in-plane loads for shear wall. Secondly, the thesis verifies the design deflection equation for nominal shear strength of CFS shear walls with OSB sheathing. the test specimens were divided into eight groups which trying to verify the design deflection equation that was published in AISI-213-07 standard.
Date: May 2012
Creator: Li, Chao
System: The UNT Digital Library
First Principle Calculations of the Structure and Electronic Properties of Pentacene Based Organic and ZnO Based Inorganic Semiconducting Materials (open access)

First Principle Calculations of the Structure and Electronic Properties of Pentacene Based Organic and ZnO Based Inorganic Semiconducting Materials

In this thesis, I utilize first principles density functional theory (DFT) based calculations to investigate the structure and electronic properties including charge transfer behaviors and work function of two types of materials: pentacene based organic semiconductors and ZnO transparent conducting oxides, with an aim to search for high mobility n-type organic semiconductors and fine tuning work functions of ZnO through surface modifications. Based on DFT calculations of numerous structure combinations, I proposed a pentacene and perfluoro-pentacene alternating hybrid structures as a new type of n-type semiconductor. Based on the DFT calculations and Marcus charge transfer theory analysis, the new structure has high charge mobility and can be a promising new n-type organic semiconductor material. DFT calculations have been used to systematically investigate the effect of surface organic absorbate and surface defects on the work function of ZnO. It was found that increasing surface coverage of organic groups and decreasing surface defects lead to decrease of work functions, in excellent agreement with experimental results. First principles based calculations thus can greatly contribute to the investigating and designing of new electronic materials.
Date: May 2012
Creator: Li, Yun
System: The UNT Digital Library
Examination of Sleep Disparities Among a Racially/ethnically Diverse Sample of Adolescents (open access)

Examination of Sleep Disparities Among a Racially/ethnically Diverse Sample of Adolescents

Racial, ethnic and gender disparities have been found among a variety of health variables, but to date no study has comprehensively examined whether similar differences exist between sleep variables such as duration, efficiency and quality, in early adolescence. There is a general consensus among previous literature that adolescence is a time when a decrease in total sleep time and an increase in sleep problems are observed. Previous literature, however, mainly focused on the influence of puberty to explain these changes. the current study examined if differences exist between 1462 Caucasian, Hispanic/Latino, and African American early adolescents (ages 10-14 years) on sleep duration, efficiency and quality. Results showed that adolescent boys reported significantly longer sleep durations, better sleep quality, shorter sleep onset latencies, and later rise times than girls. Results also showed that sixth graders slept longer than seventh and eighth graders, and that seventh graders woke up much earlier than the other two grades. Lastly, results showed that Caucasian students reported longer sleep onset latencies and lower sleep efficiencies than African American students. Trends were observed for boys having greater sleep efficiencies than girls and for Caucasian students sleeping longer than Hispanic students. Based on the differences observed in our …
Date: May 2012
Creator: Marczyk, Katherine D.
System: The UNT Digital Library
“Almost Astronauts”: Short Stories (open access)

“Almost Astronauts”: Short Stories

In this collection of short stories, I abduct experiences from my own life and take them on an imaginative journey. I experiment with elements of structure and point of view, often incorporating the magical or surreal to amplify the narrator’s internal landscape. As demonstrated in the title story, “Almost Astronauts,” these stories all deal with a sudden and sometimes destructive shift in the narrator’s perspective.
Date: May 2012
Creator: Miller, Laura I.
System: The UNT Digital Library
Live From New York and Straight to Washington: an Explorative Study of Internet Audience Perceptions of the Portrayals and Appearances of Presidential Candidates on Saturday Night Live (open access)

Live From New York and Straight to Washington: an Explorative Study of Internet Audience Perceptions of the Portrayals and Appearances of Presidential Candidates on Saturday Night Live

This thesis examines if and how the Internet viewers of Saturday Night Live skits were influenced by the video skits. the viewers’ online comments were read, categorized and analyzed for content to explore and discuss how the viewers “read” the text of the online video skits. Each video in which candidates John McCain, Sarah Palin, Hillary Clinton and Barack Obama appeared is summarized and analyzed through viewers’ comments. a sample of skits including actors’ portrayals of McCain, Palin, Clinton, Obama and Joe Biden is also summarized and analyzed to find and discuss how the viewers’ perceptions were influenced by the portrayals.
Date: May 2012
Creator: Miller, Paige Thomason
System: The UNT Digital Library
Incorporating Electrochemistry and X-ray Diffraction Experiments Into an Undergraduate Instrumental Analysis Course (open access)

Incorporating Electrochemistry and X-ray Diffraction Experiments Into an Undergraduate Instrumental Analysis Course

Experiments were designed for an undergraduate instrumental analysis laboratory course, two in X-ray diffraction and two in electrochemistry. Those techniques were chosen due their underrepresentation in the Journal of Chemical Education. Paint samples (experiment 1) and pennies (experiment 2) were characterized using x-ray diffraction to teach students how to identify different metals and compounds in a sample. in the third experiment, copper from a penny was used to perform stripping analyses at different deposition times. As the deposition time increases, the current of the stripping peak also increases. the area under the stripping peak gives the number of coulombs passed, which allows students to calculate the mass of copper deposited on the electrode surface. the fourth experiment was on the effects of variable scan rates on a chemical system. This type of experiment gives valuable mechanistic information about the chemical system being studied.
Date: May 2012
Creator: Molina, Cathy
System: The UNT Digital Library
The Myth of Strategic Superiority: Us Nuclear Weapons and Limited Conflicts, 1945-1954 (open access)

The Myth of Strategic Superiority: Us Nuclear Weapons and Limited Conflicts, 1945-1954

The nuclear age provided U.S. soldiers and statesmen with unprecedented challenges. the U.S. military had to incorporate a weapon into strategic calculations without knowing whether the use of the weapon would be approved. Broad considerations of policy led President Dwight Eisenhower to formulate a policy that relied on nuclear weapons while fully realizing their destructive potential. Despite the belief that possession of nuclear weapons provided strategic superiority, the U.S. realized that such weapons were of little value. This realization did not stop planners from attempting to find ways to use nuclear weapons in Korea and Indochina.
Date: May 2012
Creator: Morse, Eric
System: The UNT Digital Library
Western Media Attitudes Toward an Immigrant of Color Sex Crime Victim: Case Study: the DSK Case (open access)

Western Media Attitudes Toward an Immigrant of Color Sex Crime Victim: Case Study: the DSK Case

About 30 million women in the U.S. are estimated to be victims of sex crimes in their lifetimes. However, sex crimes, especially those committed against immigrants are the least reported crime in the country. Some sex crime victims say the fear of media criticism discourages them from reporting the crime. in May 2011, an African maid working at a New York hotel accused Dominique Strauss-Kahn, the former director of the International Monetary Fund, of sexually assaulting her. This qualitative content analysis examined the coverage of the DSK case, by three leading international newspapers: the New York Times, the Guardian and Le Monde. Findings suggest that Strauss-Kahn received more favorable coverage than Diallo. Frames identified in the coverage include the importance of status/prominence, race, culture differences, victim-blaming, male privilege, socioeconomic differences and focus on appearance. the study recommends that news organizations avoid judgmental coverage of sex crimes and consider identifying victims by allowing them to tell their side of the story.
Date: May 2012
Creator: Mumah, Jenny
System: The UNT Digital Library
General Paul Von Lettow-vorbeck’s East Africa Campaign: Maneuver Warfare on the Serengeti (open access)

General Paul Von Lettow-vorbeck’s East Africa Campaign: Maneuver Warfare on the Serengeti

General Paul von Lettow-Vorbeck’s East African Campaign was a conventional war of movement. Lettow based his operations on the military principles deduced from his thorough German military education and oversea deployments to China and German South West Africa. Upon assignment to German East Africa, he sought to convert the colony’s protectorate force from a counterinsurgency force to a conventional military force. His conventional strategy succeeded early in the war, especially at the Battle of Tanga in October 1914. However, his strategy failed as the war in East Africa intensified. He suffered a calamitous defeat at the Battle of Mahiwa in November 1917, and the heavy losses forced Lettow to adopt the counterinsurgency tactics of the colonial protectorate force.
Date: May 2012
Creator: Nesselhuf, F. Jon
System: The UNT Digital Library
Branded Content: Understanding the Mechanisms of Strategic Messaging in Entertainment Television Formats (open access)

Branded Content: Understanding the Mechanisms of Strategic Messaging in Entertainment Television Formats

Branded content as an advertising tactic is a growing phenomenon that is not widely researched and is generally ambiguous in nature. This study uses qualitative methods to explain how branded content is defined, how it functions, and how it can influence a brand. Case studies of IKEA and Chevrolet were compared alongside four interviews with branded content professionals. the data collected suggests that branded content in structure and substance is varied, however it comprises engagement, the brand, and financial transaction. the data collected also suggested that brands take a variety of stances when controlling content to support their brand, and that branded content generally supports the intangible aspects of a brand, as opposed to product features.
Date: May 2012
Creator: Nicholson, Danielle Marie
System: The UNT Digital Library
Analysis of Sources Affecting Ambient Particulate Matter in Brownsville, Texas (open access)

Analysis of Sources Affecting Ambient Particulate Matter in Brownsville, Texas

Texas is the second largest state in U.S.A. based on geographical area, population and the economy. It is home to several large coastal urban areas with major industries and infrastructure supporting the fossil-fuel based energy sector. Most of the major cities on the state have been impacted by significant air pollution events over the past decade. Studies conducted in the southern coastal region of TX have identified long range transport as a major contributor of particulate matter (PM) pollution along with local emissions. Biomass burns, secondary sulfates and diesel emissions sources are comprise as the dominant mass of PM2.5 have been noted to be formed by the long range transport biomass from Central America. Thus, the primary objective of this study was to identify and quantify local as well as regional sources contributing to the PM pollution in the coastal area of Brownsville located along the Gulf of Mexico. Source apportionment techniques such as principal component analysis (PCA) and positive matrix factorization (PMF) were employed on the air quality monitoring data to identify and quantify local and regional sources affecting this coastal region. As a supplement to the PMF and PCA, conditional probability function (CPF) analysis and potential source contribution …
Date: May 2012
Creator: Diaz Poueriet, Pablo
System: The UNT Digital Library