Month

151 Matching Results

Results open in a new window/tab.

After the Planes (open access)

After the Planes

The dissertation consists of a critical preface and a novel. The preface analyzes what it terms “polyvocal” novels, or novels employing multiple points of view, as well as “layered storytelling,” or layers of textuality within novels, such as stories within stories. Specifically, the first part of the preface discusses polyvocality in twenty-first century American novels, while the second part explores layered storytelling in novels responding to World War II or the terrorist attacks of 9/11. The preface analyzes the advantages and difficulties connected to these techniques, as well as their aptitude for reflecting the fractured, disconnected, and subjective nature of the narratives we construct to interpret traumatic experiences. It also acknowledges the necessity—despite its inherent limitations—of using language to engage with this fragmentation and cope with its challenges. The preface uses numerous novels as examples and case studies, and it also explores these concepts and techniques in relation to the process of writing the novel After the Planes. After the Planes depicts multiple generations of a family who utilize storytelling as a means to work through grief, hurt, misunderstanding, and loss—whether from interpersonal conflicts or from war. Against her father’s wishes, a young woman moves in with her nearly-unknown grandfather, …
Date: May 2012
Creator: Boswell, Timothy
System: The UNT Digital Library
Tactile Media: Factors Affecting the Adoption of Touchscreen Smartphones Among Consumers with Vision Loss (open access)

Tactile Media: Factors Affecting the Adoption of Touchscreen Smartphones Among Consumers with Vision Loss

Touchscreen technology is on the rise as the new standard in smartphone design. But, the usability of touchscreen is hindered for consumers that lack the physical ability to navigate such devices. Two focus groups were conducted in order to identify specific uses and gratifications that people with visual impairments had when using mobile phones. Additional questions were presented to the participants to determine if touchscreen technology limited access to communication and entertainment. The responses revealed an upward trend in touchscreen smartphone adoption among the participants. These users chose to adopt touchscreen smartphones that had built-in and downloadable assistive features which contributed to user-friendly designs.
Date: May 2012
Creator: Bradley, Sapora L.
System: The UNT Digital Library
Early College High School: Hispanic Students’ Perceptions and Experiences From a Texas Campus (open access)

Early College High School: Hispanic Students’ Perceptions and Experiences From a Texas Campus

Early college high school (ECHS) is a dual enrollment program that allows high school students to earn college credits while in high school. ECHS was developed with the intention of attracting students to pursue a 4-year college degree, especially students who might not attend college without intervention. The program targets students from low-income families, students who have low academic achievement, and students from minority groups including Hispanics, African Americans, and Native Americans. The purpose of this study was to explore the perceptions and opinions of Hispanic students about their experiences in an ECHS, and to better understand how their ECHS experiences affected motivation to engage in academics. The expectancy theory and college-going culture provided the theoretical framework for this case study. Semi-structured interviews captured the experiences of the participants. The study focused on 10 Hispanic students, 5 seniors and 5 juniors, enrolled at an ECHS located on a community college campus in Texas. The study found that students with higher motivation to work at high school and college courses had several reasons for choosing to attend ECHS. The reasons included a chance to earn a high school diploma and associate’s degree simultaneously, free college tuition, and an accelerated program to …
Date: May 2012
Creator: Brenner, Rose K.
System: The UNT Digital Library
Ecology and Recolonization of Benthic Macroinvertebrates in a Groundwater-dependent Stream in North Central Texas During a Supra-seasonal Drought (open access)

Ecology and Recolonization of Benthic Macroinvertebrates in a Groundwater-dependent Stream in North Central Texas During a Supra-seasonal Drought

Extreme climatic events such as droughts are known to eliminate aquatic biota and alter community structure and function. Perennial headwater springs provide important drought refugia to benthic macroinvertebrates and an important source of colonists via drift or aerial adults to intermittent streams post-drought. During a supra-seasonal drought in North-central Texas summer and fall 2006, benthic macroinvertebrates from persistent groundwater-dependent macrohabitats of varying hydrological connectivity and riparian shading were studied: perennial riffles, connected pools, shaded disconnected pools, and full sun disconnected pools. Riffles were a distinct habitat with significantly higher taxa richness, proportion of lotic taxa, diversity and evenness than other macrohabitats. Macrohabitats were found to be important refugia for 106 benthic macroinvertebrates and 4 microcrustacean taxa. Throughout the extreme drought, perennially flowing habitats were refugia to 19 taxa (17.9% total taxa) not collected in disconnected pools. Shaded disconnected pools contained lotic taxa not previously known to be able to complete their lifecycles in lentic habitats, emphasizing the importance of groundwater effluent and shading. With the resumption of flow at a downstream intermittent site of Ash Creek in mid-October 2006, an annual recolonization study was conducted comparing the perennial headwaters’ benthic macroinvertebrate taxa richness, densities and community ecology with the downstream …
Date: May 2012
Creator: Burk, Rosemary A.
System: The UNT Digital Library
Newspaper Ownership Structure and the Quality of Local Political News Coverage (open access)

Newspaper Ownership Structure and the Quality of Local Political News Coverage

This research sought to ascertain how newspaper ownership structures influence the quality of local political news coverage. More specifically, do independently owned newspapers tend to produce larger quantities of quality local political reporting than do corporately owned and publicly traded newspapers? In the thesis, I develop an understanding of "quality" news coverage as being coverage that is thematic, or providing interpretive analysis and supplying contextual information. Additionally, I tackle the question of quality news coverage from three angles: whether or not independently owned newspapers provide more quality local political news stories per edition than corporately owned papers; whether or not the percentage of quality local political news stories of total political news stories within an edition is higher for independently owned or corporately owned newspapers; and whether or not the percentage of total political news stories of total news stories is higher for independently owned or corporately owned newspapers.
Date: May 2012
Creator: Clark, Karla Christine Marie
System: The UNT Digital Library
Ota-quadrotor: An Object-tracking Autonomous Quadrotor for Real-time Detection and Recognition (open access)

Ota-quadrotor: An Object-tracking Autonomous Quadrotor for Real-time Detection and Recognition

The field of robotics and mechatronics is advancing at an ever-increasing rate and we are starting to see robots making the transition from the factories to the workplace and homes as cost is reduced and they become more useful. In recent years quadrotors have become a popular unmanned air vehicle (UAV) platform. These UAVs or micro air vehicles (MAV) are being used for many new and exciting applications such as aerial monitoring of wildlife, disaster sites, riots and protests. They are also being used in the film industry, as they are significantly cheaper means of getting aerial footage. While quadrotors are not extremely expensive a good system can cost in the range of $3000 - $8000 and thus too costly as a research platform for many. There are a number of cheaper open source platforms. The ArduCopter is under constant development, has the largest community and is inexpensive making it an ideal platform to work with. The goal of this thesis was to implement video processing on a ground control station allowing for the ArduCopter to track moving objects. This was achieved by using the OpenCV video-processing library to implement object tracking and the MAVLink communication protocol, available on the …
Date: May 2012
Creator: Coelho, Gavin
System: The UNT Digital Library
Perceived Effects of a Mid-length Study Abroad Program (open access)

Perceived Effects of a Mid-length Study Abroad Program

The focus of the study was the University of Dallas’ Rome Program, a mid-length study abroad program on the university’s campus in Rome, Italy. The program is designed to provide participants with the opportunity to encounter firsthand Western tradition by integrating the core curriculum through classroom teachings and class excursions, thus solidifying the foundation of the participants’ undergraduate education. Beyond this purpose, the Rome Program does not operate from established goals and objectives for student experience. I consulted relevant research literature to construct a schema of domains of development appropriate to this qualitative study. These domains were intellectual development, global perspective, career development, and spiritual development. I interviewed 20 University of Dallas seniors who participated in the mid-length study abroad program between fall 2009 and spring 2011, using an extended, semi-structured interview protocol. The participants included 11 females and 9 males; 19 White and 1 Hispanic. The findings were supported by subsequent review by 4 of the interviewed students. I found generally strong but inconsistent support for student development in each of the domains. A number of sub-themes are reported. Through the interviews, an additional theme of personal development emerged and is reported. Although the findings generally support the conclusion …
Date: May 2012
Creator: Corbin, Jill K.
System: The UNT Digital Library
Filial Therapy and the Family: Examining the Impact of Child Parent Relationship Therapy (Cprt) on Family Functioning (open access)

Filial Therapy and the Family: Examining the Impact of Child Parent Relationship Therapy (Cprt) on Family Functioning

Research has indicated that filial therapy, an approach in which parents conduct play sessions with their young children, has strong effects on the participating parents and children. As a result, some have speculated that filial therapy improves the family system; however, minimal research exists to support this claim. Using a single-case, time-series design, I examined the impact of child parent relationship therapy (CPRT), a filial therapy approach, on the functioning of 8 diverse families (two-parent, biological children = 4; two-parent, adopted children = 3; single-parent, biological children = 1). 15 parents and 17 children (male = 15, female = 17) participated in the study. All but 1 parent was Caucasian. The children were more ethnically diverse (Caucasian = 5, Hispanic/Caucasian = 5, Hispanic = 3, Asian = 2). Parents’ ages ranged from 29 to 49 and children’s from 2 to 13. Results from simulation modeling analyses (SMA) indicated that 6 of 7 families experienced a statistically significant improvement in their targeted areas of family functioning, and the average effect size was moderate. Results from self-reported measures indicated that 7 families experienced notable improvements in family satisfaction, 4 in cohesion, 3 in communication, and 1 in flexibility. Data from an observational …
Date: May 2012
Creator: Cornett, Nicholas A.
System: The UNT Digital Library
Factors Associated with Behavioral Intention to Disclose Personal Information on Geosocial Networking Applications (open access)

Factors Associated with Behavioral Intention to Disclose Personal Information on Geosocial Networking Applications

Information privacy is a major concern for consumers adopting emerging technologies dependent on location-based services. This study sought to determine whether a relationship exists among factors of personalization, locatability, perceived playfulness, privacy concern and behavioral intention to disclose personal information for individuals using location-based, geosocial networking applications. Questionnaire responses from undergraduate students at a 4-year university provide insight into these relationships. Multiple regression results indicated that there was a statistically significant relationship between the four significant predictor variables and the dependent variable. Analysis of beta weights, structure coefficients, and commonality analysis shed light on the variance attributable to the predictor variables of the study. Findings provide understanding of the specific factors examined in the study and have implications for consumers, businesses, application designers, and policymakers. The results from this study contribute to an understanding of technology acceptance theory and offer insight into competing beliefs that may affect an individual’s behavioral intention to disclose personal information. Knowledge gained form the study may be useful for overcoming challenges related to consumer adoption of location-based services that require disclosure of personal information.
Date: May 2012
Creator: Cox, Trissa
System: The UNT Digital Library
Proposed Therapeutic Art to Diminish Agitation in Elder Care (open access)

Proposed Therapeutic Art to Diminish Agitation in Elder Care

This research study examines the decreased agitation level utilizing nonpharmacological therapeutic interventions in dementia patients, age 65 and older. The study examined the following question: Will a therapeutic art program diminish agitated behaviors in persons diagnosed with dementia, aged 65 and older? In this quasi-experimental research design, the sample consisted of 19 participants in 3 groups, selected using these criteria: must be receiving services from a long term care facility, be diagnosed with dementia, display agitated behaviors, and be age 65 and older. This research measures the reduction of agitated behaviors in demented patients with the use of a therapeutic art program. The therapeutic art group pretest, midtest and posttest means were separated into Factor 1: aggressive behavior, Factor 2: physically nonaggressive behaviors, and Factor 3: verbally aggressive behavior. A multivariate analysis of covariance (ANCOVA) was conducted on the data for Factor 1, Factor 2, and Factor 3. The ANCOVA was not statistically significant for Factor 1. The ANCOVA indicated statistically significant findings when using a one tailed test for Factor 2 and Factor 3. The ANCOVA indicated statistically significant findings using a two tailed test for overall agitation. These findings inform professionals about the efficacy of therapeutic art programs …
Date: May 2012
Creator: Curington, Bonnie Dearen
System: The UNT Digital Library
Effect of Resistance Training on Cytokines in Hiv+ Men with Chemical Dependence (open access)

Effect of Resistance Training on Cytokines in Hiv+ Men with Chemical Dependence

Human immunodeficiency virus (HIV) and substance abuse (drug and/or alcohol) independently impair the immune system; importantly, the combination of HIV infection and substance abuse might produce more than an additive effect on this system. Tumor necrosis factor-alpha (TNF-?) and Interferon gamma (IFN?) are pro-inflammatory cytokines involved in differentiation of Th0 cells into Th1 cells. Interleukin 4 (IL-4) and Interleukin 10 (IL-10) are anti-inflammatory cytokine involved in differentiation of Th0 cells to Th2 cells. Unbalanced Th1 and Th2 cells can lead to immune suppression. Thus, changes in these cytokines could have important implications for people infected with HIV (HIV+). Resistance training can counteract muscle wasting, improve strength, and improve muscle mass. The purpose of this study was to examine the effect of resistance training on resting concentrations of circulating TNF-?, IFN-?, IL-4, and IL-10. Sixteen men (42 ± 11 years, 180.4 ± 9.1 cm, 89.2 ± 20.7 kg) infected with HIV and enrolled in an intensive 60-day in-patient substance addiction/abuse treatment program were recruited shortly after admission to the treatment facility. Participants were assigned to one of two groups using randomization: supervised resistance exercise 3 times per week using a progressive and non-linear periodized program (Exercise) or no exercise training (Non-Exercise) …
Date: May 2012
Creator: Curtis, John Harper
System: The UNT Digital Library
Analyzing Visitors’ Discourse, Attitudes, Perceptions, and Knowledge Acquisition in an Art Museum Tour After Using a 3D Virtual Environment (open access)

Analyzing Visitors’ Discourse, Attitudes, Perceptions, and Knowledge Acquisition in an Art Museum Tour After Using a 3D Virtual Environment

The main purpose of this mixed methods research was to explore and analyze visitors’ overall experience while they attended a museum exhibition, and examine how this experience was affected by previously using a virtual 3dimensional representation of the museum itself. The research measured knowledge acquisition in a virtual museum, and compared this knowledge acquired between a virtual museum versus a real one, employing a series of questionnaires, unobtrusive observations, surveys, personal and group interviews related to the exhibition and the artist. A group of twenty-seven undergraduate students in their first semester at the College of Architecture and Design of the Autonomous University of the State of Mexico participated in the research, and were divided in two groups, one of which used a 3D virtual representation previous to the museum visit. Results show that participants who experienced the virtual museum concurred that using it was a positive experience that prepared them to go to the real museum because they knew already what they were going to find. Most of the participants who experienced the virtual museum exhibited an increased activity during their museum visit, either agreeing, being more participative, concurring and showing acceptance, asking questions, or even giving their opinion and …
Date: May 2012
Creator: D’ Alba, Adriana
System: The UNT Digital Library
Young Journalists Today: Journalism Students’ Perceptions of the Ever-evolving Industry (open access)

Young Journalists Today: Journalism Students’ Perceptions of the Ever-evolving Industry

Today’s journalism students are learning in a time in which new technology innovations, including online news sites, blogs, and social media, have become a prominent part of the journalism industry. Whether it’s newspapers, public relations, or broadcast, technology has become a part of every area of journalism. While several studies have focused on how journalism classes should be taught in lieu of this change, how students are learning and how they feel about this changing industry has yet to be shared. This research uses both a survey of 203 current, undergraduate pre-journalism students at a large, Southwestern university, as well as focus group interviews with several subgroups of 11 of those students. The results show, not surprisingly, that journalism students are heavy users of technology and social media. They also show that a majority of journalism students prefers consuming media online. However, although students use technology and social media frequently, and also consume media online, there is evidence that suggests that they would rather learn face-to-face with an instructor than take online classes. In addition, they feel positive about their future in the changing industry.
Date: May 2012
Creator: Daniels, Stephanie
System: The UNT Digital Library
Absorptive Capacity:  An Empirical Examination of the Phenomenon and Relationships with Firm Capabilities (open access)

Absorptive Capacity: An Empirical Examination of the Phenomenon and Relationships with Firm Capabilities

The field of strategic management addresses challenges that firms encounter in an attempt to remain competitive. The ability to explain variation in firm success through examination of knowledge flows has become a prominent focus of research in the strategic management literature. Specifically, researchers have sought to further examine how firms convert knowledge, a phenomenon conceptualized as absorptive capacity. Absorptive capacity is the firm’s ability to acquire, assimilate, transform, and exploit knowledge. Few studies have captured the richness and multi-dimensionality of absorptive capacity, and it remains to be understood how the dimensions of the phenomenon convert knowledge. Furthermore, how absorptive capacity influences the firm remains to be understood. To address these research gaps, this dissertation seeks to (1) determine how absorptive capacity converts knowledge, and (2) determine how absorptive capacity influences firm capabilities. The research questions are investigated using structural modeling techniques to analyze data collected from software-industry firms. The findings offer contributions to the absorptive capacity and capability literatures. For example, absorptive capacity is hypothesized to consist of complex relationships among its internal dimensions. However, findings of this study suggest the relationships among the dimensions are linear in nature. This finding is in line with the theoretical foundations of and …
Date: May 2012
Creator: Daspit, Josh
System: The UNT Digital Library
Reducing Undesirable Behavior with Stimulus Control (open access)

Reducing Undesirable Behavior with Stimulus Control

The present experiment investigated the application of Green and Swets (1966) signal-detection theory to undesirable behavior as a method of reducing unwanted behaviors using reinforcement and extinction. This experiment investigated the use of this stimulus control technique to reduce undesirable behaviors using a multiple-baseline design. Once the cue for a target behavior was established and maintained, the use of the verbal cue was reduced in frequency and the rate of unprompted undesirable behavior was recorded. Generalization was tested across multiple people. Data for this experiment showed that undesirable behavior could be reduced by altering the stimulus control that maintained it.
Date: May 2012
Creator: Davison, Matthew Alan
System: The UNT Digital Library
A Comparison of Vocabulary Banks and Scripts on Native English-speaking Students’ Acquisition of Italian (open access)

A Comparison of Vocabulary Banks and Scripts on Native English-speaking Students’ Acquisition of Italian

The study applied behavior analytic principles to foreign language instruction in a college classroom. Two study methods, vocabulary banks and scripts, were compared by assessing the effects on Italian language acquisition, retention, and generalization. Results indicate that students without prior exposure to Italian engaged in more exchanges and emitted more words in script tests compared to vocabulary bank tests. Participants with at least two classes in Italian prior to the study engaged in more exchanges and emitted more words during vocabulary bank tests. Data suggest that different teaching strategies may work for different learners. More research is needed to determine efficient teaching methods and how to ascertain which approaches work best for learners with different histories.
Date: May 2012
Creator: Dean, Brittany L.
System: The UNT Digital Library
Graciously We Receive (open access)

Graciously We Receive

Graciously We Receive is an ethnographic documentary film about Hearts for Homes, a volunteer Christian outreach organization that does no-cost home repairs for low income elderly homeowners. Graciously We Receive examines the symbiotic relationships between volunteers and the homeowners, addressing the need to be needed by meeting the needs of others. Using qualitative research methods derived from the social sciences, Graciously We Receive represents an advancement in media-based research methods. with the introduction of quick cine-ethnography, which combines quick ethnography methods and grounded theory for data acquisition and analysis, Graciously We Receive applies anthropological research methods to documentary film production.
Date: May 2012
Creator: Dent, J. Fredrick
System: The UNT Digital Library
Implementation of Wireless Communications on Gnu Radio (open access)

Implementation of Wireless Communications on Gnu Radio

This thesis investigates the design and implementation of wireless communication system over the GNU Radio. Wireless applications are on the rise with advent of new devices, therefore there is a need to transfer the hardware complexity to software. This development enables software radio function with minimum hardware dependency. the purpose of this thesis is to design a system that will transmit compressed data via Software Defined Radio (SDR). Some parameters such as modulation scheme, bit rate can be changed to achieve the desired quality of service. in this thesis GNU (GNU’s not unix) radio is used while the hardware structure is Universal Software Radio Peripheral (USRP). in order to accomplish the goal, a compression technique called H264 (MPEG_4) encoding is applied for converting data into compressed format. the encoder was implemented in C++ to get compressed data. After encoding, the transmitter reads the compressed data and starts modulation. After modulation, the transmitter put the packets into USRP and sends it to the receiver. Once packets are received they are demodulated and then decoded to recover the original data.
Date: May 2012
Creator: Njoki, Simon M.
System: The UNT Digital Library
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
Auditors’ Information Search and Documentation: Does Knowledge of the Client Preference Or PCAOB Accountability Pressure Matter? (open access)

Auditors’ Information Search and Documentation: Does Knowledge of the Client Preference Or PCAOB Accountability Pressure Matter?

Auditors regularly make judgments regarding whether a client’s chosen accounting policy is appropriate and in accordance with generally accepted accounting Principles (GAAP). However, to form this judgment, auditors must either possess adequate topic-specific knowledge or must gain such knowledge through information search. This search is subject to numerous biases, including a bias toward confirmation of a client’s preference. It is important to further our understanding of bias in auditors’ information search to identify its causes and effects. Furthering our understanding is necessary to provide a basis for recommending and evaluating a potential debiaser, such as accountability. the Public Company Accounting Oversight Board (PCAOB) annually inspects the audit files of selected engagements, which introduces a new form of accountability within the auditing profession. This new form of accountability has come at great cost, however, there is little empirical evidence regarding its effects on auditors’ processes. As such, it is important to understand whether the presence of accountability from the PCAOB is effective in modifying auditors’ search behaviors to diminish confirmation bias. Using an online experiment, I manipulate client preference (unknown vs. known) and PCAOB accountability pressure (low vs. high) and measure search type (information –focus or decision-focus), search depth (shallow or …
Date: May 2012
Creator: Olvera, Renee M.
System: The UNT Digital Library
In Pursuit of Image: How We Think About Photographs We Seek (open access)

In Pursuit of Image: How We Think About Photographs We Seek

The user perspective of image search remains poorly understood. the purpose of this study is to identify and investigate the key issues relevant to a user’s interaction with images and the user’s approach to image search. a deeper understanding of these issues will serve to inform the design of image retrieval systems and in turn better serve the user. Previous research explores areas of information seeking behavior, representation in information science, query formulation, and image retrieval. the theoretical framework for this study includes an articulation of image search scenarios as adapted from Yoon and O’Connor’s taxonomy of image query types, Copeland’s Engineering Design Approach for rigorous qualitative research, and Anderson’s Functional Ontology Construction Model for building robust models of human behavior. a series of semi-structured interviews were conducted with expert-level image users. Interviewees discussed their motivations for image search, types of image searches they pursue, and varied approaches to image search, as well as how they decide that an information need has been met and which factors influence their experience of search. a content analysis revealed themes repeated across responses, including a collection of 23 emergent concepts and 6 emergent categories. a functional analysis revealed further insight into these themes. …
Date: May 2012
Creator: Oyarce, Sara
System: The UNT Digital Library
The Role of Tasks in the Internet Health Information Searching of Chinese Graduate Students (open access)

The Role of Tasks in the Internet Health Information Searching of Chinese Graduate Students

The purpose of the study was to examine the relationships between types of health information tasks and the Internet information search processes of Chinese graduate students at the University of North Texas. the participants' Internet information search processes were examined by looking at the source used to start the search, language selection, use of online translation tools, and time spent. in a computer classroom, 45 Chinese graduate students searched the Internet and completed three health information search tasks: factual task, interpretative task, and exploratory task. Data of the Chinese graduate students’ health information search processes were gathered from Web browser history files, answer sheets, and questionnaires. Parametric and non-parametric statistical analyses were conducted to test the relationships between the types of tasks and variables identified in the search process. Results showed that task types only had a statistically significant impact on the time spent. for the three tasks, the majority of Chinese graduate students used search engines as major sources for the search starting point, utilized English as the primary language, and did not use online translation tools. the participants also reported difficulties in locating relevant answers and recommended ways to be assisted in the future when searching the Internet …
Date: May 2012
Creator: Pan, Xuequn
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