You limited your search to:

  Partner: UNT Libraries
 Collection: UNT Theses and Dissertations
Accelerated Corrosion Test with Operation Simulation of All-Aluminum Microchannel Heat Exchangers

Accelerated Corrosion Test with Operation Simulation of All-Aluminum Microchannel Heat Exchangers

Access: Use of this item is restricted to the UNT Community.
Date: May 2016
Creator: Vaughan, Haydn
Description: The HVAC&R industry is looking to transition from copper-aluminum heat exchangers to all-aluminum microchannel technology. The want for the transition stemmed from seeing the performance improvement of all-aluminum microchannel radiators in the automotive industry. Applications differ between the two industries; therefore, applying this technology for HVAC&R use must be validated. Research towards operating modes of an all-aluminum heat exchanger in a defined corrosive environment will provide the industry with a better understanding of heat exchanger design and heat exchanger material selection. The worth in this is preventing overdesign and producing more efficient heat exchangers. Furthermore, ASHRAE members and the corrosion community will find value in a defined corrosion system and corrosion test procedure. The information gained through past research has progressed assessment of material performance; however, the methods improperly simulate and expedite natural weathering. The most common method being used is the ASTM (American Society of Testing Materials) Sea Water Acetic Acid Test. The research discussed in this paper was focused on improving a standard corrosion system by implementing system modifications to simulate heat exchanger operation while performing a modified wet-dry cyclic test (e.g. ASTM G85 Annex 5). The goal is to produce results that are more representative of natural ...
Contributing Partner: UNT Libraries
Accelerated Degree Program Faculty: Motivation to Teach

Accelerated Degree Program Faculty: Motivation to Teach

Date: May 2016
Creator: Grishkevich, Hanna Hults
Description: Adult educators are a growing part of American higher education. Because of their increasing prominence in adult education, it is essential to understand what roles these educators play and what motivates them to remain in the profession despite poor work prospects and conditions. Research to date, however, focuses primarily on the adult learner and not the adult educator. The purpose of this qualitative, multiple-case study was to explore the role and motivation for teaching of adult educators employed as adjunct faculty in an accelerated degree program at a small, liberal arts college in the northwest United States. Purposeful sampling was used to select the five participants for the study. All participants taught in the program for more than five years and were considered to be successful in their positions by peers, students, and administrators. The study employed a preliminary demographic survey to solicit initial background data on the instructors. Other data collection included in-depth, open-ended, face-to-face interviews, document analysis, and classroom observation. The results showed that all five participants identified the following roles and assumed them in the classroom: (a) facilitator, (b) listener, (c) specialist, (d) guide, (e) adviser, and (f) co-learner or colleague. Further results showed that all five ...
Contributing Partner: UNT Libraries
Addressing Social Elements of Wildfire: Risk, Response, and Recovery in Highland Village, TX

Addressing Social Elements of Wildfire: Risk, Response, and Recovery in Highland Village, TX

Date: May 2016
Creator: MacKinnon, Jessica
Description: Representatives of the City of Highland Village expressed concern over the risk of wildfires for their community. Anthropology provides many tools for and examples of disaster assessment of preparedness, response, recovery, and mitigation. These tools combined with Geographic Information Systems (GIS) can provide a holistic, cultural ecological look at how such a disaster may take place in the city. The project's methods included a detailed survey of preparedness steps which was analyzed using SPSS and also imported into ArcGIS for spatial analysis, and semi-formal, in-depth interviews with residents of the community regarding preparedness, response, and recovery. Residents fell into a middle category of preparedness, with the majority of participants considering or implementing a few recommended preparedness steps. Interview participants expressed respect for and trust of the city and first-responders, as well as a willingness to volunteer their help during response and recovery stages. Finally the American Community Survey showed that resident socioeconomic vulnerability was considerably low, and no action needed to be taken to advocate for at-risk individuals. Overall, the City of Highland Village showed a high resiliency to disaster. A wildfire likely will not have a major impact on the community as a whole, though the city may reduce ...
Contributing Partner: UNT Libraries
Adhesion and Surface Energy Profiles of Large-area Atomic Layers of Two-dimensional MoS2 on Rigid Substrates by Facile Methods

Adhesion and Surface Energy Profiles of Large-area Atomic Layers of Two-dimensional MoS2 on Rigid Substrates by Facile Methods

Access: Use of this item is restricted to the UNT Community.
Date: May 2016
Creator: Wu, Min
Description: Two-dimensional (2D) transition metal dichalcogenides (TMDs) show great potential for the future electronics, optoelectronics and energy applications. But, the studies unveiling their interactions with the host substrates are sparse and limits their practical use for real device applications. We report the facile nano-scratch method to determine the adhesion energy of the wafer scale MoS2 atomic layers attached to the SiO2/Si and sapphire substrates. The practical adhesion energy of monolayer MoS2 on the SiO2/Si substrate is 7.78 J/m2. The practical adhesion energy was found to be an increasing function of the MoS2 thickness. Unlike SiO2/Si substrates, MoS2 films grown on the sapphire possess higher bonding energy, which is attributed to the defect-free growth and less number of grain boundaries, as well as less stress and strain stored at the interface owing to the similarity of Thermal Expansion Coefficient (TEC) between MoS2 films and sapphire substrate. Furthermore, we calculated the surface free energy of 2D MoS2 by the facile contact angle measurements and Neumann model fitting. A surface free energy ~85.3 mJ/m2 in few layers thick MoS2 manifests the hydrophilic nature of 2D MoS2. The high surface energy of MoS2 helps explain the good bonding strength at MoS2/substrate interface. This simple adhesion ...
Contributing Partner: UNT Libraries
The adoption, management, and performance of local government investment pools: A comparative analysis of state practices.

The adoption, management, and performance of local government investment pools: A comparative analysis of state practices.

Date: May 2016
Creator: Nukpezah, Julius Atsu
Description: This dissertation examines the factors influencing a state’s decision to adopt a local government investment pool (LGIP), the institutional arrangements used in managing them, and the effect of the institutional types on LGIP performance. The dissertation extends the policy adoption theory with insights from investment theory to demonstrate that management credibility influences the likelihood of a state’s LGIP adoption. The study finds that the quality of financial management, the quality of professional leadership, proximate state neighbors who have previously adopted an LGIP, and economic factors determine a state’s proclivity to policy adoption. The dissertation also describes the institutional arrangements used in managing LGIPs and develops typologies based on their institutional arrangements. The dissertation compares LGIPs depending on the risk aversion of their institutional arrangements. The research extends the risk-return tradeoff in investment theory to LGIP institutional arrangements. The empirical findings show that LGIP institutional arrangement that has greater risk report higher performance. The dissertation also finds that competition in the LGIP market due to multiple vendors, and periods of economic recession account for higher performance because of higher risk-taking behaviors associated with them. This dissertation promotes public funds investment laws that emphasize prudent management of government finances and guides managers ...
Contributing Partner: UNT Libraries
AirSniffer: A Smartphone-Based Sensor Module for Personal Micro-Climate Monitoring

AirSniffer: A Smartphone-Based Sensor Module for Personal Micro-Climate Monitoring

Date: May 2016
Creator: Smith, Jeffrey Paul
Description: Environmental factors can have a significant impact on an individual's health and well-being, and a primary characteristic of environments is air quality. Air sensing equipment is available to the public, but it is often expensive,stationary, or unusable for persons without technical expertise. The goal of this project is to develop an inexpensive and portable sensor module for public use. The system is capable of measuring temperature in Celsius and Fahrenheit, heat index, relative humidity, and carbon dioxide concentration. The sensor module, referred to as the "sniffer," consists of a printed circuit board that interconnects a carbon dioxide sensor, a temperature/humidity sensor, an Arduino microcontroller, and a Bluetooth module. The sniffer is small enough to be worn as a pendant or a belt attachment, and it is rugged enough to consistently collect and transmit data to a user's smartphone throughout their workday. The accompanying smartphone app uses Bluetooth and GPS hardware to collect data and affix samples with a time stamp and GPS coordinates. The accumulated sensor data is saved to a file on the user's phone, which is then examined on a standard computer.
Contributing Partner: UNT Libraries
Analysis and Optimization of Graphene FET based Nanoelectronic Integrated Circuits

Analysis and Optimization of Graphene FET based Nanoelectronic Integrated Circuits

Access: Use of this item is restricted to the UNT Community.
Date: May 2016
Creator: Joshi, Shital
Description: Like cell to the human body, transistors are the basic building blocks of any electronics circuits. Silicon has been the industries obvious choice for making transistors. Transistors with large size occupy large chip area, consume lots of power and the number of functionalities will be limited due to area constraints. Thus to make the devices smaller, smarter and faster, the transistors are aggressively scaled down in each generation. Moore's law states that the transistors count in any electronic circuits doubles every 18 months. Following this Moore's law, the transistor has already been scaled down to 14 nm. However there are limitations to how much further these transistors can be scaled down. Particularly below 10 nm, these silicon based transistors hit the fundamental limits like loss of gate control, high leakage and various other short channel effects. Thus it is not possible to favor the silicon transistors for future electronics applications. As a result, the research has shifted to new device concepts and device materials alternative to silicon. Carbon is the next abundant element found in the Earth and one of such carbon based nanomaterial is graphene. Graphene when extracted from Graphite, the same material used as the lid in pencil, ...
Contributing Partner: UNT Libraries
An Analysis of Educational Technology Publications:  Who, What and Where in the Last 20 Years

An Analysis of Educational Technology Publications: Who, What and Where in the Last 20 Years

Date: May 2016
Creator: Natividad Beltran Del Rio, Gloria Ofelia
Description: This exploratory and descriptive study examines research articles published in ten of the top journals in the broad area of educational technology during the last 20 years: 1) Educational Technology Research and Development (ETR&D); 2) Instructional Science; 3) Journal of the Learning Sciences; 4) TechTrends; 5) Educational Technology: The Magazine for Managers of Change in Education; 6) Journal of Educational Technology & Society; 7) Computers and Education; 8) British Journal of Educational Technology (BJET); 9) Journal of Educational Computing Research; and 10) Journal of Research on Technology in Education. To discover research trends in the articles published from 1995-2014, abstracts from all contributing articles published in those ten prominent journals were analyzed to extract a latent semantic space of broad research areas, top authors, and top-cited publications. Concepts that have emerged, grown, or diminished in the field were noted in order to identify the most dominant in the last two decades; and the most frequent contributors to each journal as well as those who contributed to more than one of the journals studied were identified.
Contributing Partner: UNT Libraries
Analysis of Factors for Successful State-Level Support of Low-Performing Schools

Analysis of Factors for Successful State-Level Support of Low-Performing Schools

Date: May 2016
Creator: Ewing, Angela R.
Description: This study provides a qualitative look at Texas' Professional Service Providers' (PSPs) strategies for supporting low-performing schools. Four PSPs were selected for participation based on the number of schools they helped exit the Texas Title I School Improvement Program from 2007-2012. Data collected and analyzed included provider and principal interviews, providers' progress reports documenting services, and principals' evaluations of provider services. Results indicated key support strategies in two of four cases were supporting and mentoring/coaching while communicating and building trust were important in the other two cases. Communicating, reviewing information, and planning were important across all cases. The quality indicators aligning with the PSPs' strategies were fit, comprehensiveness, and coherence. They were also the most common across all cases. Finally, analysis of the evaluation of provider services revealed PSP-1 with the highest ratings, followed by PSP-2, PSP-3, and PSP-4 respectively. The findings suggest, first, that PSP support has a dual nature. Contextual support was provided based on the campus leaderships' skills and requests. PSPs also ensured coherence among the strategies of all stakeholders. Secondly, a hierarchy of quality service indicators aligned to the PSPs' strategies: fit, comprehensiveness, and coherence. Finally relationships are vital to a successful provider-campus relationship. The findings ...
Contributing Partner: UNT Libraries
An Analysis of the Leadership Competency Frameworks of Nontraditional Principal Preparation Programs

An Analysis of the Leadership Competency Frameworks of Nontraditional Principal Preparation Programs

Date: May 2016
Creator: Horton, Tonya Marie
Description: This study explored the competency frameworks of nontraditional principal preparation programs to determine how they aligned to research-based best practices for school leaders. The research questions that guided this work were: To what degree are the McREL 21 Leadership Responsibilities addressed in the competency frameworks of nontraditional principal preparation programs? How do the leaders of the nontraditional principal preparation programs view the degree to which their competencies include the McREL 21 Leadership Responsibilities? A multi-case study analysis was conducted that compared the competency frameworks of four nontraditional principal preparation programs. The Knowledge is Power Program (KIPP), New Leaders, New York City Leadership Academy (NYCLA), and Teaching Trust were the nontraditional programs selected for this study. Leaders from the four organizations were interviewed. The findings from the research illustrated that a majority of the McREL 21 Leadership Responsibilities were included in the competency frameworks of nontraditional principal preparation programs. The study revealed that four of the McREL 21 were not included in any of the competency frameworks. Another finding was the lack of focus on talent management and personal dispositions in the McREL 21 Leadership Responsibilities. Nontraditional principal preparation programs are a growing avenue for principal preparation, as such their use ...
Contributing Partner: UNT Libraries
FIRST PREV 1 2 3 4 5 NEXT LAST