Partner
UNT Libraries Government Documents Department
480
Oklahoma Historical Society
184
National Museum of the Pacific War/Admiral Nimitz Foundation
15
UNT Libraries
15
UNT Libraries Special Collections
13
Sterling Municipal Library
10
San Antonio Public Library
8
Carl Albert Congressional Research and Studies Center
7
UNT Music Library
5
Dallas Area Rapid Transit (DART)
4
50 More
Collection
Office of Scientific & Technical Information Technical Reports
341
Jim Argo Collection
146
Texas Digital Newspaper Program
100
Government Accountability Office Reports
76
Congressional Research Service Reports
58
Oklahoma Digital Newspaper Program
47
Tocker Foundation Grant
43
National Museum of the Pacific War Oral History Collection
15
National Museum of the Pacific War Digital Archive
15
The Greensheet
11
87 More
Degree Department
Degree Discipline
Degree Level
Country
States
Decade
Month
Day
823 Matching Results
Results open in a new window/tab.
Results:
1 - 24 of
823
next
Hydrogen Storage Properties of Magnesium Base Nanostructured Composite Materials
In this work, nanostructured composite materials have been synthesized using the mechanical alloying process. The new materials produced have been investigated by X-ray diffraction (XRD), transition electron microscope (TEM), scanning electron microscope (SEM) and electron energy dispersion spectrum (EDS) for their phase compositions, crystal structure, grain size, particle morphology and the distribution of catalyst element. Hydrogen storage capacities and the hydriding-dehydriding kinetics of the new materials have been measured at different temperatures using a Sieverts apparatus. It is observed that mechanical alloying accelerates the hydrogenation kinetics of the magnesium based materials at low temperature, but a high temperature must be provided to release the absorbed hydrogen from the hydrided magnesium based materials. It is believed that the dehydriding temperature is largely controlled by the thermodynamic configuration of magnesium hydride. Doping Mg-Ni nano/amorphous composite materials with lanthanum reduces the hydriding and dehydriding temperature. Although the stability of MgH2 can not be easily reduced by ball milling alone, the results suggest the thermodynamic properties of Mg-Ni nano/amorphous composite materials can be alternated by additives such as La or other effective elements. Further investigation toward understanding the mechanism of additives will be rewarded.
Date:
April 30, 2004
Creator:
AU, M
Object Type:
Article
System:
The UNT Digital Library
Analysis of Homogeneous Charge Compression Ignition (HCCI) Engines for Cogeneration Applications
This paper presents an evaluation of the applicability of Homogeneous Charge Compression Ignition Engines (HCCI) for small-scale cogeneration (less than 1 MWe) in comparison to five previously analyzed prime movers. The five comparator prime movers include stoichiometric spark-ignited (SI) engines, lean burn SI engines, diesel engines, microturbines and fuel cells. The investigated option, HCCI engines, is a relatively new type of engine that has some fundamental differences with respect to other prime movers. Here, the prime movers are compared by calculating electric and heating efficiency, fuel consumption, nitrogen oxide (NOx) emissions and capital and fuel cost. Two cases are analyzed. In Case 1, the cogeneration facility requires combined power and heating. In Case 2, the requirement is for power and chilling. The results show that the HCCI engines closely approach the very high fuel utilization efficiency of diesel engines without the high emissions of NOx and the expensive diesel fuel. HCCI engines offer a new alternative for cogeneration that provides a unique combination of low cost, high efficiency, low emissions and flexibility in operating temperatures that can be optimally tuned for cogeneration systems. HCCI engines are the most efficient technology that meets the oncoming 2007 CARB NOx standards for cogeneration …
Date:
April 30, 2004
Creator:
Aceves, S; Martinez-Frias, J & Reistad, G
Object Type:
Article
System:
The UNT Digital Library
Effect of Radiation on Spinel Ceramics for Permanent Containers for Nuclear Waste Transportation and Storage.
None
Date:
April 30, 2000
Creator:
Adams, J.; Cowgill, M.; Moskowitz, P. & Rokhvarger, A.
Object Type:
Article
System:
The UNT Digital Library
Effect of Radiation on Spinel Ceramics for Permanent Containers for Nuclear Waste Transportation and Storage.
None
Date:
April 30, 2000
Creator:
Adams, J.; Cowgill, M.; Moskowitz, P. & Rokhvarger, A.
Object Type:
Article
System:
The UNT Digital Library
Hydrogen Storage in metal-modified single-walled carbon nanotubes
It has been known for over thirty years that potassium-intercalated graphites can readily adsorb and desorb hydrogen at {approx}1 wt% at 77 K. These levels are much higher than can be attained in pure graphite, owing to a larger thermodynamic enthalpy of adsorption. This increased enthalpy may allow hydrogen sorption at higher temperatures. Potassium has other beneficial effects that enable the design of a new material: (a) Increased adsorption enthalpy in potassium-intercalated graphite compared to pure graphite reduces the pressure and increases the temperature required for a given fractional coverage of hydrogen adsorption. We expect the same effects in potassium-intercalated SWNTs. (b) As an intercalant, potassium separates c-axis planes in graphite. Potassium also separates the individual tubes of SWNTs ropes producing swelling and increased surface area. Increased surface area provides more adsorption sites, giving a proportionately higher capacity. The temperature of adsorption depends on the enthalpy of adsorption. The characteristic temperature is roughly the adsorption enthalpy divided by Boltzmann's constant, k{sub B}. For the high hydrogen storage capacity of SWNTs to be achieved at room temperature, it is necessary to increase the enthalpy of adsorption. Our goal for this project was to use metal modifications to the carbon surface of …
Date:
April 30, 2004
Creator:
Ahn, Dr.
Object Type:
Report
System:
The UNT Digital Library
Project Work Plan 100-N Area Strontium-90 Treatability Demonstration Project: Phytoremediation Along the 100-N Columbia River Riparian Zone
The 100-N Area Innovative Treatment and Remediation Demonstration (ITRD) identified phyto¬remediation as a potential technology both for the removal of 90Sr from the soil of the riparian zone and as a filter for groundwater along the Columbia River. Recent greenhouse and growth chamber studies have demonstrated the viability of phytoextraction to remove 90Sr from this area’s soil/water; in conjunction with monitored natural attenuation and an apatite barrier the process would make an effective treatment for remediation of the 100-N Area 90Sr plume. All activities associated with the 100-NR-1 and 100-NR-2 Operable Units of the Hanford 100-N Area have had, and continue to have, significant regulatory and stakeholder participation. Beginning in 1998 with the ITRD process, presentations to the ITRD TAG were heavily attended by EPA, Washington State Department of Ecology, and stakeholders. In addition, three workshops have been held to receive regulatory and stakeholder feedback on monitored natural attenuation, the apatite barrier, and phytoremediation; these were held in Richland in August 2003, December 2004, and August 2005. The apatite injection treatability test plan (DOE 2005) describes phytoremediation as a technology to be evaluated during the March 2008 evaluation milestone as described in the Tri-Party Agreement change request (M-16-06-01 Change Control …
Date:
April 30, 2006
Creator:
Ainsworth, Calvin C.
Object Type:
Report
System:
The UNT Digital Library
Excitation of the synchro-betatron resonances by the beam-beam interaction in the Tevatron Run II lattice
Effect of different mechanisms of the synchro-betatron coupling (dispersion function at the interaction points, chromatic tune modulation, finite bunch length) on the p-bar stability in the Tevatron Run II configuration is considered. It is found that the long-range interactions in the presence of large dispersion produce large contribution ({approximately}10) to the chromaticity of the betatron tunes. This chromaticity, in its turn, can give rise to multiple synchrotron satellites of the betatron resonances increasing their effective width. Novel formulae are presented which permit to significantly speed up analytical calculations of the beam-beam tuneshifts and resonance strength.
Date:
April 30, 2001
Creator:
Alexahin, Yuri I.
Object Type:
Report
System:
The UNT Digital Library
Timpson & Tenaha News (Timpson, Tex.), Vol. 28, No. 16, Ed. 1 Thursday, April 30, 2009
Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.
Date:
April 30, 2009
Creator:
Alexander, Nancy
Object Type:
Newspaper
System:
The Portal to Texas History
Tanks Focus Area Site Needs Assessment - FY 2001
The TFA uses a systematic process for developing its annual program that draws from the tanks science and technology development needs expressed by the five DOE tank waste sites. TFA's annual program development process is iterative and involves the following steps: Collection of site needs; Needs analysis; Development of technical responses and initial prioritization; Refinement of the program for the next fiscal year; Formulation of the Corporate Review Budget (CRB); Preparation of Program Execution Guidance (PEG) for the next FY Revision of the Multiyear Program Plan (MYPP). This document describes the outcomes of the first phase of this process, from collection of site needs to the initial prioritization of technical activities. The TFA received site needs in October - December 2000. A total of 170 site needs were received, an increase of 30 over the previous year. The needs were analyzed and integrated, where appropriate. Sixty-six distinct technical responses were drafted and prioritized. In addition, seven strategic tasks were approved to compete for available funding in FY 2002 and FY 2003. Draft technical responses were prepared and provided to the TFA Site Representatives and the TFA User Steering Group (USG) for their review and comment. These responses were discussed at …
Date:
April 30, 2001
Creator:
Allen, Bob W; Josephson, Gary B; Westsik, Joseph H & Nickola, Cheryl L
Object Type:
Report
System:
The UNT Digital Library
Tanks Focus Area Site Needs Assessment - FY 2001
The TFA uses a systematic process for developing its annual program that draws from the tanks science and technology development needs expressed by the five DOE tank waste sites. TFA's annual program development process is iterative and involves the following steps: Collection of site needs; Needs analysis; Development of technical responses and initial prioritization; Refinement of the program for the next fiscal year; Formulation of the Corporate Review Budget (CRB); Preparation of Program Execution Guidance (PEG) for the next FY Revision of the Multiyear Program Plan (MYPP). This document describes the outcomes of the first phase of this process, from collection of site needs to the initial prioritization of technical activities. The TFA received site needs in October - December 2000. A total of 170 site needs were received, an increase of 30 over the previous year. The needs were analyzed and integrated, where appropriate. Sixty-six distinct technical responses were drafted and prioritized. In addition, seven strategic tasks were approved to compete for available funding in FY 2002 and FY 2003. Draft technical responses were prepared and provided to the TFA Site Representatives and the TFA User Steering Group (USG) for their review and comment. These responses were discussed at …
Date:
April 30, 2001
Creator:
Allen, Robert W.; Josephson, Gary B.; Westsik, Joseph H. & Nickola, Cheryl L.
Object Type:
Report
System:
The UNT Digital Library
Improving Paper Machine Efficiency
None
Date:
April 30, 2000
Creator:
Allun, Cyrus
Object Type:
Report
System:
The UNT Digital Library
Colleges and Universities Attended by Representatives of the 108th Congress
This report identifies the colleges and universities attended by representatives and delegates in the 107th Congress grouped by state.
Date:
April 30, 2003
Creator:
Amer, Mildred L.
Object Type:
Report
System:
The UNT Digital Library
Colleges and Universities Attended by Senators of the 108th Congress
This report identifies the colleges and universities attended by Senators serving in the 108th Congress.
Date:
April 30, 2003
Creator:
Amer, Mildred L.
Object Type:
Report
System:
The UNT Digital Library
Plasma Biasing to Control the Growth Conditions of Diamond-Like Carbon
It is well known that the structure and properties ofdiamond-like carbon, and in particular the sp3/sp2 ratio, can becontrolled by the energy of the condensing carbon ions or atoms. In manypractical cases, the energy of ions arriving at the surface of thegrowing film is determined by the bias applied to the substrate. The biascauses a sheath to form between substrate and plasma in which thepotential difference between plasma potential and surface potentialdrops. In this contribution, we demonstrate that the same results can beobtained with grounded substrates by shifting the plasma potential. This"plasma biasing" (as opposed to "substrate biasing") is shown to workwell with pulsed cathodic carbon arcs, resulting in tetrahedral amorphouscarbon (ta-C) films that are comparable to the films obtained with theconventional substrate bias. To verify the plasma bias approach, ta-Cfilms were deposited by both conventional and plasma bias andcharacterized by transmission electron microscopy (TEM) and electronenergy loss spectrometry (EELS). Detailed data for comparison of thesefilms are provided.
Date:
April 30, 2006
Creator:
Anders, Andre; Pasaja, Nitisak; Lim, Sunnie H.N.; Petersen, TimC. & Keast, Vicki J.
Object Type:
Article
System:
The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 106, No. 26, Ed. 1 Friday, April 30, 2004
Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date:
April 30, 2004
Creator:
Andrews, Mike
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Nonlinear Projective-Iteration Methods for Solving Transport Problems on Regular and Unstructured Grids
This is a project in the field of fundamental research on numerical methods for solving the particle transport equation. Numerous practical problems require to use unstructured meshes, for example, detailed nuclear reactor assembly-level calculations, large-scale reactor core calculations, radiative hydrodynamics problems, where the mesh is determined by hydrodynamic processes, and well-logging problems in which the media structure has very complicated geometry. Currently this is an area of very active research in numerical transport theory. main issues in developing numerical methods for solving the transport equation are the accuracy of the numerical solution and effectiveness of iteration procedure. The problem in case of unstructured grids is that it is very difficult to derive an iteration algorithm that will be unconditionally stable.
Date:
April 30, 2007
Creator:
Anistratov, Dmitriy Y.; Constantinescu, Adrian; Roberts, Loren & Wieselquist, William
Object Type:
Report
System:
The UNT Digital Library
Formulation of Moist Dynamics and Physics for Future Climate Models
In this project, one of our goals is to develop atmospheric models, in which innovative ideas on improving the quality of moisture predictions can be tested. Our other goal is to develop an explicit time integration scheme based on the multi-point differencing that does the same job as an implicit trapezoidal scheme but uses information only from limited number of grid points.
Date:
April 30, 2008
Creator:
Arakwa, Celal S. Konor and Akio
Object Type:
Text
System:
The UNT Digital Library
Anisotropic x-ray magnetic linear dichroism at the Fe L2,3 edgesin Fe3O4
X-ray magnetic linear dichroism at the Fe L{sub 2,3} edges of the ferrimagnet Fe{sub 3}O{sub 4} was found to exhibit a strong dependence on the relative orientation of external magnetic field, x-ray polarization, and crystalline axes. Spectral shape and magnitude of the effect were determined for Fe{sub 3}O{sub 4}(011) and Fe{sub 3}O{sub 4}(001) thin films varying the in-plane orientation of field and polarization. All dichroism spectra can be described as a linear combination of three fundamental spectra which in turn give a good agreement with calculated spectra using atomic multiplet theory. The angular dependence of the magnetic dichroism reflects the crystal field symmetry. It can be used to estimate the crystal field splitting and allows determining the spin quantization axis.
Date:
April 30, 2006
Creator:
Arenholz, Elke; van der Laan, Gerrit; Chopdekar, Rajesh V. & Suzuki, Yuri
Object Type:
Article
System:
The UNT Digital Library
Bricktown
Photograph of a scene on the Bricktown Canal.
Date:
April 30, 2001
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Bricktown
Photograph of a scene on the Bricktown Canal.
Date:
April 30, 2001
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Bricktown
Photograph of a scene on the Bricktown Canal.
Date:
April 30, 2001
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Bricktown
Photograph of a scene on the Bricktown Canal.
Date:
April 30, 2001
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Bricktown
Photograph of a scene on the Bricktown Canal.
Date:
April 30, 2001
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History
Bricktown
Photograph of a scene on the Bricktown Canal.
Date:
April 30, 2001
Creator:
Argo, Jim
Object Type:
Photograph
System:
The Gateway to Oklahoma History