Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires (open access)

Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires

Thermoelectric materials have generated interest as a means of increasing the efficiency of power generation through the scavenging of waste heat. Materials containing nanometer-sized structural and compositional features can exhibit enhanced thermoelectric performance due to the decoupling of certain electrical and thermal properties, but the extent to which these features can be controlled is often limited. Here we report a simple synthesis of M{sub 2}O{sub 3}(ZnO){sub n} (M = In, Ga, Fe) nanowires with controllable polytypoid structures, where the nanostructured features are tuned by adjusting the amount of metal precursor. After the introduction of nanometer-scale features (individual atomic layers and alloying), thermal and electrical measurements on single In{sub 2-x}Ga{sub x}O3(ZnO){sub n} nanowires reveal a simultaneous improvement in all contributing factors to the thermoelectric figure of merit, indicating successful modification of the nanowire transport properties.
Date: October 23, 2010
Creator: Andrews, Sean C.; Fardy, Melissa A.; Moore, Michael C.; Aloni, Shaoul; Zhang, Minjuan; Radmilovic, Velimir et al.
Object Type: Article
System: The UNT Digital Library
Compact Cdznte-Based Gamma Camera for Prostate Cancer Imaging (open access)

Compact Cdznte-Based Gamma Camera for Prostate Cancer Imaging

In this paper, we discuss the design of a compact gamma camera for high-resolution prostate cancer imaging using Cadmium Zinc Telluride (CdZnTe or CZT) radiation detectors. Prostate cancer is a common disease in men. Nowadays, a blood test measuring the level of prostate specific antigen (PSA) is widely used for screening for the disease in males over 50, followed by (ultrasound) imaging-guided biopsy. However, PSA tests have a high false-positive rate and ultrasound-guided biopsy has a high likelihood of missing small cancerous tissues. Commercial methods of nuclear medical imaging, e.g. PET and SPECT, can functionally image the organs, and potentially find cancer tissues at early stages, but their applications in diagnosing prostate cancer has been limited by the smallness of the prostate gland and the long working distance between the organ and the detectors comprising these imaging systems. CZT is a semiconductor material with wide band-gap and relatively high electron mobility, and thus can operate at room temperature without additional cooling. CZT detectors are photon-electron direct-conversion devices, thus offering high energy-resolution in detecting gamma rays, enabling energy-resolved imaging, and reducing the background of Compton-scattering events. In addition, CZT material has high stopping power for gamma rays; for medical imaging, a …
Date: October 23, 2011
Creator: Cui, Y.; Lall, T.; Tsui, B.; Yu, J.; Mahler, G.; Bolotnikov, A. et al.
Object Type: Article
System: The UNT Digital Library
Development of an instrument for non-destructive identification of Unexploded Ordnance using tagged neutrons - a proof of concept study (open access)

Development of an instrument for non-destructive identification of Unexploded Ordnance using tagged neutrons - a proof of concept study

Range clearance operations at munitions testing grounds must discriminate Unexploded Ordnance (UXO) from clutter items and distinguish UXO filled with High Explosives (HE) from those with inert fillers. Non-destructive technologies are thus necessary for the cost-effective disposal of UXO during remediation of such sites. The only technique showing promise so far for the non-destructive elemental characterization of UXO fillers utilizes neutron interactions with the material to detect carbon (C), nitrogen (N) and oxygen (O) which have unique ratios in HE. However, several unresolved issues hinder the wide application of this potentially very suitable technique. The most important one is that neutrons interact with all surrounding matter in addition to the interrogated material, leading to a very high gamma-ray background in the detector. Systems requiring bulky shielding and having poor signal-to-noise ratios (SNRs) for measuring elements are unsuitable for field deployment. The inadequacies of conventional neutron interrogation methods are overcome by using the tagged-neutron approach, and the availability of compact sealed neutron generators exploiting this technique offers field deployment of non-intrusive measurement systems for detecting threat materials, like explosives and drugs. By accelerating deuterium ions into a tritium target, the subsequent fusion reaction generates nearly back-to-back emissions of neutrons and alpha …
Date: October 23, 2011
Creator: Mitra, S. & Dioszegi, I.
Object Type: Article
System: The UNT Digital Library
Development of Cdznte Radiation Detectors (open access)

Development of Cdznte Radiation Detectors

Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for room-temperature semiconductor detectors because of its wide band-gap and high atomic number. Despite these advantages, CZT still presents some material limitations and poor hole mobility. In the past decade most of the developing CZT detectors focused on designing different electrode configurations, mainly to minimize the deleterious effect due to the poor hole mobility. A few different electrode geometries were designed and fabricated, such as pixelated anodes and Frisch-grid detectors developed at Brookhaven National Lab (BNL). However, crystal defects in CZT materials still limit the yield of detector-grade crystals, and, in general, dominate the detector's performance. In the past few years, our group's research extended to characterizing the CZT materials at the micro-scale, and to correlating crystal defects with the detector's performance. We built a set of unique tools for this purpose, including infrared (IR) transmission microscopy, X-ray micro-scale mapping using synchrotron light source, X-ray transmission- and reflection-topography, current deep level transient spectroscopy (I-DLTS), and photoluminescence measurements. Our most recent work on CZT detectors was directed towards detailing various crystal defects, studying the internal electrical field, and delineating the effects of thermal annealing on improving the material properties. In …
Date: October 23, 2011
Creator: Bolotnikov, A.; Camarda, G.; Hossain, A.; Kim, K. H.; Yang, G.; Gul, R. et al.
Object Type: Article
System: The UNT Digital Library
EVALUATION OF POTENTIAL ELUANTS FOR NON-ACID ELUTION OF CESIUM FROM SPHERICAL RESORCINOL-FORMALDEHYDE RESIN (open access)

EVALUATION OF POTENTIAL ELUANTS FOR NON-ACID ELUTION OF CESIUM FROM SPHERICAL RESORCINOL-FORMALDEHYDE RESIN

Ion Exchange column loading and elution of cesium from spherical resorcinol-formaldehyde resin have been conducted for two potential non-acid eluants -(NH{sub 4}){sub 2}CO{sub 3} and CH{sub 3}COONH{sub 4}. The results revealed encouraging cesium elution performance. 100% elution was achieved in at most 22 hours ({approx}28 bed volumes) of elution. Elution performance was fairly high at 6 hours ({approx}8 bed volumes) of elution for some of the eluants and also practically comparable to the benchmark acid eluant (HNO{sub 3}). Hence, it is quite possible 100% percent elution will be closer to the 6th hour than the 22nd hour. Elution is generally enhanced by increasing the concentration and pH of the eluants, and combining the eluants.
Date: October 23, 2011
Creator: Adu-Wusu, K.; Nash, C. & Pennebaker, F.
Object Type: Article
System: The UNT Digital Library
Goethite Bench-scale and Large-scale Preparation Tests (open access)

Goethite Bench-scale and Large-scale Preparation Tests

The Hanford Waste Treatment and Immobilization Plant (WTP) is the keystone for cleanup of high-level radioactive waste from our nation's nuclear defense program. The WTP will process high-level waste from the Hanford tanks and produce immobilized high-level waste glass for disposal at a national repository, low activity waste (LAW) glass, and liquid effluent from the vitrification off-gas scrubbers. The liquid effluent will be stabilized into a secondary waste form (e.g. grout-like material) and disposed on the Hanford site in the Integrated Disposal Facility (IDF) along with the low-activity waste glass. The major long-term environmental impact at Hanford results from technetium that volatilizes from the WTP melters and finally resides in the secondary waste. Laboratory studies have indicated that pertechnetate ({sup 99}TcO{sub 4}{sup -}) can be reduced and captured into a solid solution of {alpha}-FeOOH, goethite (Um 2010). Goethite is a stable mineral and can significantly retard the release of technetium to the environment from the IDF. The laboratory studies were conducted using reaction times of many days, which is typical of environmental subsurface reactions that were the genesis of this new process. This study was the first step in considering adaptation of the slow laboratory steps to a larger-scale and …
Date: October 23, 2011
Creator: Josephson, Gary B. & Westsik, Joseph H.
Object Type: Report
System: The UNT Digital Library
The Arabidopsis Wave Complex: Mechanisms Of Localized Actin Polymerization And Growth (open access)

The Arabidopsis Wave Complex: Mechanisms Of Localized Actin Polymerization And Growth

The objective of this project was to discover the protein complexes and control mechanisms that determine the location of actin filament roadways in plant cells. Our work provided the first molecular description of protein complexes that are converted from inactive complexes to active actin filament nucleators in the cell. These discoveries provided a conceptual framework to control to roadways in plant cells that determine the location and delivery of plant metabolites and storage molecules that are relevant to the bioenergy economy.
Date: October 23, 2012
Creator: Szymanski, Daniel
Object Type: Report
System: The UNT Digital Library
Campaign Finance Guide for Political Committees (open access)

Campaign Finance Guide for Political Committees

This guide is a summary of the campaign finance regulations applicable to political committees.
Date: October 23, 2012
Creator: Texas Ethics Commission
Object Type: Book
System: The Portal to Texas History
CO{sub 2} Sequestration Potential of Charqueadas Coal Field in Brazil (open access)

CO{sub 2} Sequestration Potential of Charqueadas Coal Field in Brazil

The I2B coal seam in the Charqueadas coal field has been evaluated as a target for enhanced coal bed methane production and CO{sub 2} sequestration. The samples were low rank coals (high volatile bituminous and sub-bituminous) obtained from the I2B seam as �3� cores. Such properties as sorption capacity, internal structure of the samples, porosity and permeability were of primary interest in this characterization study.
Date: October 23, 2012
Creator: Romanov, V.
Object Type: Article
System: The UNT Digital Library
Conceptual Design Parameters for MITR LEU-MO Fuel Conversion Demonstration Experimental Irradiations (open access)

Conceptual Design Parameters for MITR LEU-MO Fuel Conversion Demonstration Experimental Irradiations

None
Date: October 23, 2012
Creator: Wilson, E. H.; Newton, T. H., Jr.; Hu, L.; Dunn, F. E. & Stevens, J. G.
Object Type: Report
System: The UNT Digital Library
Defense Acquisitions: Future Aerostat and Airship Investment Decisions Drive Oversight and Coordination Needs (open access)

Defense Acquisitions: Future Aerostat and Airship Investment Decisions Drive Oversight and Coordination Needs

A letter report issued by the Government Accountability Office with an abstract that begins "GAO identified 15 key aerostat and airship efforts that were underway or had been initiated since 2007, and the Department of Defense (DOD) had or has primary responsibility for all of these efforts. None of the civil agency efforts met GAO's criteria for a key effort. Most of the aerostat and airship efforts have been fielded or completed, and are intended to provide intelligence, surveillance, and reconnaissance (ISR) support. The estimated total funding of these efforts was almost $7 billion from fiscal years 2007 through 2012. However, funding estimates beyond fiscal year 2012 decline precipitously for aerostat and airship efforts under development, although there is an expectation that investment in the area will continue."
Date: October 23, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF HTS CONDUCTORS FOR ELECTRIC POWER APPLICATIONS (open access)

DEVELOPMENT OF HTS CONDUCTORS FOR ELECTRIC POWER APPLICATIONS

Second generation (2G) technologies to fabricate high-performance superconducting wires developed at the Oak Ridge National Laboratory (ORNL) were transferred to American Superconductor via this CRADA. In addition, co-development of technologies for over a decade was done to enable fabrication of commercial high-temperature superconducting (HTS) wires with high performance. The massive success of this CRADA has allowed American Superconductor Corporation (AMSC) to become a global leader in the fabrication of HTS wire and the technology is fully based on the Rolling Assisted Biaxially Textured Substrates (RABiTS) technology invented and developed at ORNL.
Date: October 23, 2012
Creator: Goyal, A. & Rupich, M. (American Superconductor Corp.)
Object Type: Report
System: The UNT Digital Library
Distinguishing Plutonium Metal from Plutonium Oxide Using Fast Neutrons, Preliminary Experimental Results (open access)

Distinguishing Plutonium Metal from Plutonium Oxide Using Fast Neutrons, Preliminary Experimental Results

None
Date: October 23, 2012
Creator: Verbeke, J M & Chapline, G F
Object Type: Report
System: The UNT Digital Library
Employment for Veterans: Trends and Programs (open access)

Employment for Veterans: Trends and Programs

This report discusses veterans' employment trends and programs. The first section presents data on veterans' employment outcomes, identifying recent trends, and discussing issues to consider when interpreting veterans' employment data. The following sections present brief discussions of existing programs that provide employment-related services to veterans. These services are divided into (1) general programs that are broadly available to veterans, (2) programs that target veterans with service-connected disabilities, and (3) competitive grant programs that provide additional employment-related services to veterans but may be limited in scope or availability.
Date: October 23, 2012
Creator: Collins, Benjamin; Bradley, David H.; Dortch, Cassandria; Kapp, Lawrence & Scott, Christine
Object Type: Report
System: The UNT Digital Library
Energy and Water Development: Fiscal Year 2013 Appropriations (open access)

Energy and Water Development: Fiscal Year 2013 Appropriations

Report that discusses the FY2012 budget for energy and water development as approved by Congress, including how the funding will be used.
Date: October 23, 2012
Creator: Behrens, Carl E.
Object Type: Report
System: The UNT Digital Library
Grain Sorting in Cometary Dust from the Outer Solar Nebula (open access)

Grain Sorting in Cometary Dust from the Outer Solar Nebula

None
Date: October 23, 2012
Creator: Wozniakiewicz, P J; Bradley, J P; Ishii, H A; Brownlee, D E; Kearsley, A T; Burchell, M J et al.
Object Type: Article
System: The UNT Digital Library
Promoting Global Internet Freedom: Policy and Technology (open access)

Promoting Global Internet Freedom: Policy and Technology

Report that provides information about federal and private sector efforts to promote and support global Internet freedom, a description of Internet freedom legislation from the 112th Congress, and suggestions for further reading on this topic. Two appendixes describe censorship and circumvention technologies.
Date: October 23, 2012
Creator: Moloney Figliola, Patricia
Object Type: Report
System: The UNT Digital Library
Afghanistan: Post-Taliban Governance, Security, and U.S. Policy (open access)

Afghanistan: Post-Taliban Governance, Security, and U.S. Policy

This report discusses the current political state of Afghanistan, focusing particularly on the influence of the Taliban and other militant groups and on the leadership of Afghan President Hamid Karzai. This report also discusses the U.S.-Afghanistan relationship, in both the short and long term, and U.S. efforts under the Obama Administration to provide military, reconstructive, and stabilization aid.
Date: October 23, 2013
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Background on the Scheduled Reduction to Supplemental Nutrition Assistance Program (SNAP) Benefits (open access)

Background on the Scheduled Reduction to Supplemental Nutrition Assistance Program (SNAP) Benefits

This report discusses Background on the Scheduled Reduction to Supplemental Nutrition Assistance Program (SNAP) Benefits.
Date: October 23, 2013
Creator: Aussenberg, Randy Alison & Falk, Gene
Object Type: Report
System: The UNT Digital Library
Chemical Regulation in the European Union (EU): Registration, Evaluation, and Authorization of Chemicals (open access)

Chemical Regulation in the European Union (EU): Registration, Evaluation, and Authorization of Chemicals

On June 1, 200, the European Union (EU) began to implement a new law governing chemicals in EU commerce: Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH). It is intended to protect human health and the environment from hazardous chemicals while at the same time protecting the competitiveness of European industry. This report contains information on the background, how each part of the REACH law are implemented, and related materials.
Date: October 23, 2013
Creator: Yen, Jerry H.
Object Type: Report
System: The UNT Digital Library
Final Report to B&W Y-12 for MPO4300089700, Rev. 1 (open access)

Final Report to B&W Y-12 for MPO4300089700, Rev. 1

None
Date: October 23, 2013
Creator: Mok, G C
Object Type: Report
System: The UNT Digital Library
The G-20 and International Economic Cooperation: Background and Implications for Congress (open access)

The G-20 and International Economic Cooperation: Background and Implications for Congress

This report discusses the background of the G-20 (an international forum for discussing and coordinating economic policies) and some of the issues that it has addressed. It includes historic background on the work of the G-20, information about how the group operates, overviews of G-20 summits, major issues that the group is likely to address and the likely effectiveness of the G-20 in the near future. The members of the G-20 include Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United Kingdom, the United States, and the European Union.
Date: October 23, 2013
Creator: Nelson, Rebecca M.
Object Type: Report
System: The UNT Digital Library
In Brief: CRS Resources on the FY2014 Funding Gap, Shutdown, and Status of Appropriations (open access)

In Brief: CRS Resources on the FY2014 Funding Gap, Shutdown, and Status of Appropriations

This report provides an annotated list of Congressional Research Service (CRS) resources and analyses relevant tothe funding gap that commenced on October 1, 2013, and terminated on October 17, 2013, with the enactment of P.L. 113-46, a continuing appropriations measure providing appropriations through January 15, 2014; historical funding gaps; and continuing appropriations measures.
Date: October 23, 2013
Creator: Murray, Justin
Object Type: Report
System: The UNT Digital Library
Joint Military Education: Actions Needed to Implement DOD Recommendations for Enhancing Leadership Development (open access)

Joint Military Education: Actions Needed to Implement DOD Recommendations for Enhancing Leadership Development

A letter report issued by the Government Accountability Office with an abstract that begins ""
Date: October 23, 2013
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library