1,366 Matching Results

Results open in a new window/tab.

Interfacial Characterization of Chemical Vapor Deposition (Cvd) Grown Graphene and Electrodeposited Bismuth on Ruthenium Surface (open access)

Interfacial Characterization of Chemical Vapor Deposition (Cvd) Grown Graphene and Electrodeposited Bismuth on Ruthenium Surface

Graphene receives enormous attention owing to its distinctive physical and chemical prosperities. Growing and transferring graphene to different substrates have been investigated. The graphene growing on the copper substrate has an advantage of low solubility of carbon on the copper which allow us to grow mostly monolayer graphene. Graphene sheet of few centimeters can be transferred to 300nm silicon oxide and quartz crystal pre-deposited with metal like Cu and Ru. Characterization of the graphene has been done with Raman and contact angle measurement and recently quartz crystal microbalance (QCM) has been employed. The underpotential deposition (UPD) process of Bi on Ru metal surface is studied using electrochemical quartz crystal microbalance (EQCM) and XPS techniques. Both Bi UPD and Bi bulk deposition are clearly observed on Ru in 1mM Bi (NO3)3/0.5M H2SO4. Bi monolayer coverage calculated from mass (MLMass) and from charge (MLCharge) were compared with respect to the potential scanning rates, anions and ambient controls. EQCM results indicate that Bi UPD on Ru is mostly scan rate independent but exhibits interesting difference at the slower scan. Bi UPD monolayer coverage calculated from cathodic frequency change (ΔfCathodic) is significantly smaller than the monolayer coverage derived from integrated charge under the cathodic …
Date: May 2014
Creator: Abdelghani, Jafar
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Jacques-Antoine-Hippolyte, Comte De Guibert: Father of the Grande Armée (open access)

Jacques-Antoine-Hippolyte, Comte De Guibert: Father of the Grande Armée

Jacques-Antoine-Hippolyte, comte de Guibert (1743-1790) dedicated his life and career to creating a new doctrine for the French army. Little about this doctrine was revolutionary. Indeed, Guibert openly decried the anarchy of popular participation in government and looked askance at the early days of the Revolution. Rather, Guibert’s doctrine marked the culmination of an evolutionary process that commenced decades before his time and reached fruition in the Réglement of 1791, which remained in force until the 1830s. Not content with military reform, Guibert demanded a political and social constitution to match. His reforms required these changes, demanding a disciplined, service-oriented society and a functional, rational government to assist his reformed military. He delved deeply, like no other contemporary writer, into the linkages between society, politics, and the military throughout his career and his writings. Guibert exerted an overwhelming influence on military thought across Europe for the next fifty years. His military theories provided the foundation for military reform during the twilight of the Old Regime. The Revolution, which adopted most of Guibert’s doctrine in 1791, continued his work. A new army and way of war based on Guibert’s reforms emerged to defeat France’s major enemies. In Napoleon’s hands, Guibert’s army …
Date: August 2014
Creator: Abel, Jonathan, 1985-
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Source Apportionment Analysis of Measured Volatile Organic Compounds in Corpus Christi, Texas (open access)

Source Apportionment Analysis of Measured Volatile Organic Compounds in Corpus Christi, Texas

Corpus Christi among of the largest industrialized coastal urban areas in Texas. The strategic location of the city along the Gulf of Mexico allows for many important industries and an international business to be located. The cluster of industries and businesses in the region contribute to the air pollution from emissions that are harmful to the environment and to the people living in and visiting the area. Volatile organic compounds (VOC) constitute an important class of pollutants measured in the area. The automated gas chromatography (Auto GC) data was collected from Texas Commission of Environmental Quality (TCEQ) and source apportionment analysis was conducted on this data to identify key sources of VOC affecting this study region. EPA PMF 3.0 was employed in this sources apportionment study of measured VOC concentration during 2005 - 2012 in Corpus Christi, Texas. The study identified nine optimal factors (Source) that could explain the concentration of VOC at two urbane monitoring sites in the study region. Natural gas was found to be the largest contributor of VOC in the area, followed by gasoline and vehicular exhaust. Diesel was the third highest contributor with emissions from manufacturing and combustion processes. Refineries gases and evaporative fugitive emissions …
Date: May 2014
Creator: Abood, Ahmed T.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Development of a Cost Effective Wireless Sensor System for Indoor Air Quality Monitoring Applications (open access)

Development of a Cost Effective Wireless Sensor System for Indoor Air Quality Monitoring Applications

Poor air quality can greatly affect the public health. Research studies indicate that indoor air can be more polluted than the outdoor air. An indoor air quality monitoring system will help to create an awareness of the quality of air inside which will eventually help in improving it. The objective of this research is to develop a low cost wireless sensor system for indoor air quality monitoring. The major cost reduction of the system is achieved by using low priced sensors. Interface circuits had to be designed to make these sensors more accurate. The system is capable of measuring carbon dioxide, carbon monoxide, ozone, temperature, humidity and volatile organic compounds. The prototype sensor node modules were developed. The sensor nodes were the connected together by Zigbee network. The nodes were developed in such a way that it is compact in size and wireless connection of sensor nodes enable to collect air quality data from multiple locations simultaneously. The collected data was stored in a computer. We employed linear least-square approach for the calibration of each sensor to derive a conversion formula for converting the sensor readings to engineering units. The system was tested with different pollutants and data collected was …
Date: May 2014
Creator: Abraham, Sherin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Exploratory Analysis of Social E-health Behavior (open access)

Exploratory Analysis of Social E-health Behavior

Extant literature has documented well that people seek health information via the internet as patients and consumers. Much less, however, is known about interaction and creation behaviors in the development of new online health information and knowledge. More specifically, generalizable sociodemographic data on who engages in this online health behavior via social media is lacking in the sociological literature. The term “social e-health” is introduced to emphasize the difference between seeking behaviors and interaction and creation behaviors. A 2010 dataset of a large nationally representative and randomly sampled telephone survey made freely available from the Pew Research Center is used to examine social e-health behavior according to respondents’ sociodemographics. The dependent variable of social e-health behavior is measured by 13 survey questions from the survey. Gender, race, ethnicity, age, education, and income are used as independent variables. Logistic regression analysis was used to determine the odds of engagement in social e-health behavior based on the sociodemographic predictors. The social determinants of health and digital divide frameworks are used to help explain why socioeconomic variances exist in social e-health behavior. The findings of the current study suggest that predictable sociodemographic patterns along the dimensions of gender, race, age, education, and income …
Date: May 2014
Creator: Acadia, Spencer
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Processing, Structure and Tribological Property Relations of Ternary Zn-Ti-O and Quaternary Zn-Ti-Zr-O Nanocrystalline Coatings (open access)

Processing, Structure and Tribological Property Relations of Ternary Zn-Ti-O and Quaternary Zn-Ti-Zr-O Nanocrystalline Coatings

Conventional liquid lubricants are faced with limitations under extreme cyclic operating conditions, such as in applications that require lubrication when changing from atmospheric pressure to ultrahigh vacuum and ambient air to dry nitrogen (e.g., satellite components), and room to elevated (>500°C) temperatures (e.g., aerospace bearings). Alternatively, solid lubricant coatings can be used in conditions where synthetic liquid lubricants and greases are not applicable; however, individual solid lubricant phases usually perform best only for a limited range of operating conditions. Therefore, solid lubricants that can adequately perform over a wider range of environmental conditions are needed, especially during thermal cycling with temperatures exceeding 500°C. One potential material class investigated in this dissertation is lubricious oxides, because unlike other solid lubricant coatings they are typically thermodynamically stable in air and at elevated temperatures. While past studies have been focused on binary metal oxide coatings, such as ZnO, there have been very few ternary oxide and no reported quaternary oxide investigations. The premise behind the addition of the third and fourth refractory metals Ti and Zr is to increase the number of hard and wear resistant phases while maintaining solid lubrication with ZnO. Therefore, the major focus of this dissertation is to investigate …
Date: August 2014
Creator: Ageh, Victor
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Family Structure and Marijuana Use Among Adolescents (open access)

Family Structure and Marijuana Use Among Adolescents

Family structure as a predictive variable of juvenile delinquency has been studied for the last hundred years. This relationship originated due to societal belief that divorce was detrimental to adolescents. Due to the changing societal roles in the United States, family structure has been changing. More children are growing up in non-intact families, such as single-parent households, households with stepparents, cohabitating families, and households without a parent present. To study the effect family structure has on juvenile delinquency, researchers have utilized social control theory, differential association, self-control theory and general strain theory to conceptualize variables to explain why family structure influences delinquent behavior. A review of previous literature on this topic indicates that living in intact households, which are households with two biological parents who are married, have, on average, the lowest rates of delinquency. This thesis investigates the relationship between family structure and lifetime marijuana use among eighth and tenth grade adolescents in the United States through the use of secondary data analysis of Monitoring the Future Study, 2012. The results provide support for the relationship between family structure and lifetime marijuana use.
Date: May 2014
Creator: Aguilar, Jamie M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Assessing the Costs of Climate Change and Adaptation in South Asia (open access)

Assessing the Costs of Climate Change and Adaptation in South Asia

.This Asian Development Bank (ADB) study examined the economic costs associated with the impacts of climate change and the cost and benefits of adaptation in Bangladesh,Bhutan, India, the Maldives, Nepal, and Sri Lanka. The study aimed to (i) assess the biophysical impacts of climate change in the region, including individual country impacts, and (ii) estimate the total economic loss to the countries in the region by 2100, taking into account the different scenarios and impacts projected across vulnerable sectors, and then to estimate the magnitude of funding for adaptation measures required to avert such potential losses. Results of the study will aid development of future policies and programs for climate change adaptation in the region, including initiatives for regional cooperation and capacity building in climate change management. The study covered the following sectors: agriculture, terrestrial ecosystems, water, marine and coastal resources (except Bhutan and Nepal), health, and energy.
Date: June 1, 2014
Creator: Ahmed, Mahfuz & Suphachol Suphachalasai
Object Type: Text
System: The UNT Digital Library
Low Leakage Asymmetric Stacked Sram Cell (open access)

Low Leakage Asymmetric Stacked Sram Cell

Memory is an important part of any digital processing system. On-chip SRAM can be found in various levels of the memory hierarchy in a processor and occupies a considerable area of the chip. Leakage is one of the challenges which shrinking of technology has introduced and the leakage of SRAM constitutes a substantial part of the total leakage power of the chip due to its large area and the fact that many of the cells are idle without any access. In this thesis, we introduce asymmetric SRAM cells using stacked transistors which reduce the leakage up to 26% while increasing the delay of the cell by only 1.2% while reducing the read noise margin of the cell by only 15.7%. We also investigate an asymmetric cell configuration in which increases the delay by 33% while reduces the leakage up to 30% and reducing the read noise margin by only 1.2% compared to a regular SRAM cell.
Date: May 2014
Creator: Ahrabi, Nina
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Space in Space: Privacy Needs for Long-Duration Spaceflight (open access)

Space in Space: Privacy Needs for Long-Duration Spaceflight

Space exploration is a uniquely human activity. As humans continue to push the limits of exploring the unknown, they have sought knowledge supporting the sustenance of life in outer space. New technologies, advancements in medicine, and rethinking what it means to be a “community” will need to emerge to support life among the stars. Crews traveling beyond the Moon will rely on the development of new technologies to support the technological aspects of their missions as well as their quality of life while away from Earth. Likewise, through advancements in medicine, scientists will need to address remaining questions regarding the effects of long-duration spaceflight on the human body and crew performance. Space explorers must learn to utilize these new technologies and medical advancements while learning to adapt to their new environment in space and as a space community. It is important that researchers address these issues so that human survival beyond Earth is not only achievable but so that life among the stars is worth living and sustaining. This thesis addressed these issues in an attempt to extend the trajectory of space exploration to new horizons.
Date: May 2014
Creator: Aiken, Jo
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Ensuring Long-Term Access to Electronic Theses and Dissertations: Local vs. Global Lifecycle Management

Presentation for the 2014 Texas Library Association (TLA) Annual Conference. This presentation discusses ensuring long-term access to electronic theses and dissertations and local versus global lifecycle management.
Date: April 2014
Creator: Alemneh, Daniel Gelaw
Object Type: Presentation
System: The UNT Digital Library
Interviews with SIG/III Co-founders: Reflections of Toni Carbo and Michel Menou (open access)

Interviews with SIG/III Co-founders: Reflections of Toni Carbo and Michel Menou

Article discussing interviews with the Special Interest Group/International Information Issues (SIG/III) co-founders Toni Carbo and Michel Menou.
Date: June 19, 2014
Creator: Alemneh, Daniel Gelaw
Object Type: Article
System: The UNT Digital Library
Metadata for ETD Lifecycle Management (open access)

Metadata for ETD Lifecycle Management

Chapter from Guidance Documents for Lifecycle Management of ETDs. This chapter describes the roles of metadata in facilitating the ETD lifecycle, methods to capture metadata manually and automatically, examples of programs using metadata to enhance ETD access, and strategies to manage metadata over time.
Date: March 21, 2014
Creator: Alemneh, Daniel Gelaw
Object Type: Book Chapter
System: The UNT Digital Library

Research and Successful Promotion at UNT Libraries

Presentation describes how there are multiple paths to promotion as a librarian at UNT. It details the ways in which employees with UNT libraries are able to be successful in academia and higher education.
Date: November 20, 2014
Creator: Alemneh, Daniel Gelaw
Object Type: Presentation
System: The UNT Digital Library

Restricted University of North Texas Electronic Theses and Dissertations

This dataset contains responses to a survey questionnaire distributed by the University of North Texas (UNT) Libraries asking 125 authors of electronic theses and dissertations (ETDs) whether they agree to change the existing restricted permission status on their ETDs.
Date: February 24, 2014
Creator: Alemneh, Daniel Gelaw
Object Type: Dataset
System: The UNT Digital Library
Theses and Dissertations from Print to ETD: The Nuances of Preserving and Accessing Those in Music (open access)

Theses and Dissertations from Print to ETD: The Nuances of Preserving and Accessing Those in Music

Book chapter discussing the unique challenges of digitizing music theses and dissertations.
Date: 2014
Creator: Alemneh, Daniel Gelaw & Hartsock, Ralph
Object Type: Book Chapter
System: The UNT Digital Library

The Evolving Landscape of Scholarly Communication: Stakeholders' Roles in a Global Ecosystem

Presentation for a panel at the 2014 University Partnerships Workshop, sponsored by the U. S. Department of State and the U. S. Embassy, Islamabad, Pakistan. This presentation discusses the evolving landscape of scholarly communication and stakeholders' roles in a global ecosystem.
Date: November 14, 2014
Creator: Alemneh, Daniel Gelaw & Hawkins, Kevin S.
Object Type: Presentation
System: The UNT Digital Library
Facilitating Discovery and Use of Digital Cultural Heritage Resources with Folksonomies: A Review (open access)

Facilitating Discovery and Use of Digital Cultural Heritage Resources with Folksonomies: A Review

This article explores the strengths and limitations of folksonomies through traditional indexing and taxonomies with an emphasis on the history of cultural heritage information retrieval.
Date: June 2014
Creator: Alemneh, Daniel Gelaw & Rorissa, Abebe
Object Type: Book Chapter
System: The UNT Digital Library
Introduction: International Information Issues and ASIS&T (open access)

Introduction: International Information Issues and ASIS&T

Article introducing a special section of the Bulletin of the Association for Information Science and Technology (ASIS&T) featuring interviews, discussions of ASIS&T chapters and SIGs roles, networking activities, and past and current organizational initiatives.
Date: June 19, 2014
Creator: Alemneh, Daniel Gelaw & Rorissa, Abebe
Object Type: Article
System: The UNT Digital Library
Guidance Documents for Lifecycle  Management of ETDs (open access)

Guidance Documents for Lifecycle Management of ETDs

In 2011, a research team led by the University of North Texas, the Educopia Institute/MetaArchive Cooperative, and the worldwide Networked Digital Library of Theses and Dissertations (NDLTD), began studying the production, dissemination, and preservation of Electronic Theses and Dissertations (ETDs). The original intent was to develop and disseminate documentation for academic libraries that would help curators better understand and address the preservation challenges presented by these new digital collections. As researchers from the libraries of University of North Texas, Virginia Tech, Rice University, Boston College, Indiana State University, Penn State, and the University of Arizona began to grapple with ETD lifecycle management issues, they quickly realized that librarians were but one of many academic stakeholder groups that work collaboratively to produce and maintain ETD collections. Studying the library role in isolation was neither feasible nor helpful. The scope of our work increased to encompass the roles and responsibilities of core stakeholders in the ETD lifecycle: students, faculty, administrators, technologists, commercial vendors, and librarians. The resulting Guidance Documents address areas of interest to ETD program planners, managers, and curators. They will help this extended set of stakeholders understand, document, and address the administrative, legal, and technical challenges presented by ETDs—from submission …
Date: March 19, 2014
Creator: Alemneh, Daniel Gelaw; Donovan, Bill; Halbert, Martin; Han, Yan; Henry, Geneva; Hswe, Patricia et al.
Object Type: Book
System: The UNT Digital Library

Open Access and ETDs

Poster presented at the 2014 United States (U.S) Electronic Theses and Dissertations (ETDs) Annual Conference. This poster discusses open access and ETDs.
Date: September 2014
Creator: Alemneh, Daniel Gelaw; Phillips, Mark Edward & Kleister, Jill
Object Type: Poster
System: The UNT Digital Library

Pushing the Boundaries of Open Access

Poster presented at the 2014 Texas Conference on Digital Libraries (TCDL). This poster provides a preliminary analysis of the University of North Texas (UNT) efforts to make students' work accessible to a wider global audience.
Date: April 28, 2014
Creator: Alemneh, Daniel Gelaw; Phillips, Mark Edward & Kleister, Jill
Object Type: Poster
System: The UNT Digital Library
The Use of Social Media in Informal Scientific Communication Among Scholars: Modeling the Modern Invisible College (open access)

The Use of Social Media in Informal Scientific Communication Among Scholars: Modeling the Modern Invisible College

The concept of the invisible college is a key focus of scientific communication research with many studies on this topic in the literature. However, while such studies have contributed to an understanding of the invisible college, they have not adequately explained the interaction of social and structural processes in this phenomenon. As a consequence, past research has described the invisible college differently based on researchers’ perspectives, resulting in misinterpretations or inconsistent definitions of the relevant social and structural processes. Information science and related disciplines have focused on the structural processes that lead to scholarly products or works while placing less emphasis on the social processes. To advance understanding of the invisible college and its dimensions (including both social processes and structural processes), a proposed model (Modern Invisible College Model, MICM) has been built based on the history of the invisible college and Lievrouw’s (1989) distinction between social and structural processes. The present study focuses on the social processes of informal communication between scholars via social media, rather than on the structural processes that lead to scholarly products or works. A developed survey and an employed quantitative research method were applied for data collection. The research population involved 77 scholars from …
Date: May 2014
Creator: Algarni, Mohammed Ayedh
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Role of the Actin Cytoskeleton in Asymmetric Cell Division in Maize (open access)

The Role of the Actin Cytoskeleton in Asymmetric Cell Division in Maize

Stomata are specialized plant structures required for gaseous exchange with the outer environment. During stomata formation, the cytoskeleton plays an important role in controlling the division of the individual cells leading to the generation of the stomata complex. Two mutants that affect microfilament and microtubule organization in subsidiary mother cells include brk1 and dcd1. While only 20% of the subsidiary cells in the brk1 and dcd1 single mutants are abnormally shaped, it was reported that there is a synergistic effect between the brk1 and dcd1 mutations in the brk1; dcd1 double mutant since 100% of the subsidiary cells are abnormal. The focus of this research is to try to understand this synergistic effect by investigating the actin cytoskeleton and nuclear position in the single and double mutants. The reported results include the observation that the size of actin patch was largest in the wild-type subsidiary mother cells (SMCs) and smallest in dcd1 and brk1; dcd1 SMCs and that brk1 and brk1; dcd1 double mutants had fewer actin patches than wild-type and dcd1 SMCs. Additionally, we observed that some SMCs that did not have actin patches still underwent nuclear migration suggesting that nuclear migration may not be solely dependent on actin …
Date: August 2014
Creator: Alhassan, Hassan Hamdan
Object Type: Thesis or Dissertation
System: The UNT Digital Library