Degree Department

1,754 Matching Results

Results open in a new window/tab.

300 Degree C GaN/AlGaN Heterojunction Bipolar Transistor (open access)

300 Degree C GaN/AlGaN Heterojunction Bipolar Transistor

A GaN/AIGaN heterojunction bipolar transistor has been fabricated using C12/Ar dry etching for mesa formation. As the hole concentration increases due to more efficient ionization of the Mg acceptors at elevated temperatures (> 250oC), the device shows improved gain. Future efforts which are briefly summarized. should focus on methods for reducing base resistance.
Date: October 14, 1998
Creator: Abernathy, C. R.; Baca, A. G.; Cho, H.; Chow, P. P.; Han, J.; Hichman, R. A. et al.
Object Type: Article
System: The UNT Digital Library
324/327 facilities environmental effluent specifications (open access)

324/327 facilities environmental effluent specifications

These effluent technical specifications address requirements for the 324/327 facilities, which are undergoing stabilization activities. Effluent technical specifications are imposed to protect personnel, the environment and the public, by ensuring adequate implementation and compliance with federal and state regulatory requirements and Hanford programs.
Date: October 29, 1998
Creator: JOHNSON, D.L.
Object Type: Report
System: The UNT Digital Library
324 Facility B-cell quality process plan (open access)

324 Facility B-cell quality process plan

Quality Process Plan for the Restart of Cell Hot-Work. Addition of Table 4.
Date: October 27, 1998
Creator: Carlson, J. L.
Object Type: Report
System: The UNT Digital Library
324 Facility B-cell quality process plan (open access)

324 Facility B-cell quality process plan

Quality Process Plan for the Restart of Cell Hot-Work. Addition of Table 5a.
Date: October 27, 1998
Creator: RIDDELLE, J.G.
Object Type: Report
System: The UNT Digital Library
12th International Mouse Genome Conference (open access)

12th International Mouse Genome Conference

None
Date: October 1, 1998
Creator: unknown
Object Type: Article
System: The UNT Digital Library
15th Street News (Midwest City, Okla.), Vol. 28, No. 5, Ed. 1 Friday, October 2, 1998 (open access)

15th Street News (Midwest City, Okla.), Vol. 28, No. 5, Ed. 1 Friday, October 2, 1998

Newspaper from Rose State College in Midwest City, Oklahoma that includes national, local, and campus news along with advertising.
Date: October 2, 1998
Creator: Pace, Joshua
Object Type: Newspaper
System: The Gateway to Oklahoma History
15th Street News (Midwest City, Okla.), Vol. 28, No. 6, Ed. 1 Friday, October 9, 1998 (open access)

15th Street News (Midwest City, Okla.), Vol. 28, No. 6, Ed. 1 Friday, October 9, 1998

Newspaper from Rose State College in Midwest City, Oklahoma that includes national, local, and campus news along with advertising.
Date: October 9, 1998
Creator: Pace, Joshua
Object Type: Newspaper
System: The Gateway to Oklahoma History
15th Street News (Midwest City, Okla.), Vol. 28, No. 7, Ed. 1 Friday, October 23, 1998 (open access)

15th Street News (Midwest City, Okla.), Vol. 28, No. 7, Ed. 1 Friday, October 23, 1998

Newspaper from Rose State College in Midwest City, Oklahoma that includes national, local, and campus news along with advertising.
Date: October 23, 1998
Creator: Pace, Joshua
Object Type: Newspaper
System: The Gateway to Oklahoma History
15th Street News (Midwest City, Okla.), Vol. 28, No. 8, Ed. 1 Friday, October 30, 1998 (open access)

15th Street News (Midwest City, Okla.), Vol. 28, No. 8, Ed. 1 Friday, October 30, 1998

Newspaper from Rose State College in Midwest City, Oklahoma that includes national, local, and campus news along with advertising.
Date: October 30, 1998
Creator: Pace, Joshua
Object Type: Newspaper
System: The Gateway to Oklahoma History
1997 Annual Site Environmental Report (ASER) (open access)

1997 Annual Site Environmental Report (ASER)

The SLAC program centers around experimental and theoretical research in elementary particle physics using accelerated electron beams and a broad program of research in atoms and solid-state physics, chemistry, and biology using synchrotron radiation from accelerated electron beams. There is also an active program in the development of accelerators, detectors, and new sources and instrumentation for synchrotron radiation research. The main instrument of research is the 3.2-km linear accelerator (linac) that generates high intensity beams of electrons and positrons up to 50 GeV, which are among the highest energy electron and positron beams available in the world. The linac is also used for injecting electrons and positrons into colliding-beam storage rings for particle physics research. The Positron-Electron Project (PEP) storage ring is about 800 meters in diameter. The PEP program was completed several years ago. PEP is now being upgraded to serve as an Asymmetric B Factory (or PEP-II) that will study the B meson. PEP-II will make use of much of PEP's existing equipment and infrastructure, and is scheduled for completion in 1998. A smaller storage ring, the Stanford Positron-Electron Asymmetric Ring (SPEAR) has its own smaller linac and a booster ring for injecting accelerated beams of electrons. SPEAR …
Date: October 1, 1998
Creator: Holden, Gene
Object Type: Report
System: The UNT Digital Library
1998 federal energy and water management award winners (open access)

1998 federal energy and water management award winners

Energy is a luxury that no one can afford to waste, and many Federal Government agencies are becoming increasingly aware of the importance of using energy wisely. Thoughtful use of energy resources is important, not only to meet agency goals, but because energy efficiency helps improve air quality. Sound facility management offers huge savings that affect the agency`s bottom line, the environment, and workplace quality. In these fiscally-modest times, pursuing sound energy management programs can present additional challenges for energy and facility managers. The correct path to take is not always the easiest. Hard work, innovation, and vision are characteristic of those who pursue energy efficiency. That is why the Department of energy, Federal Energy Management Program (FEMP) is proud to salute the winners of the 1998 Federal Energy and Water Management Award. The 1998 winners represent the kind of 21st century thinking that will help achieve widespread Federal energy efficiency. In one year, the winners, through a combination of public and private partnerships, saved more than $222 million and 10.5 trillion Btu by actively identifying and implementing energy efficiency, water conservation, and renewable energy projects. Through their dedication, hard work, ingenuity, and success, the award winners have also inspired …
Date: October 28, 1998
Creator: unknown
Object Type: Report
System: The UNT Digital Library
1998 federal technical standards workshop: Proceedings (open access)

1998 federal technical standards workshop: Proceedings

The theme for the 1998 workshop was Standards Management -- A World of Change and Opportunities. The workshop`s goal was to further the implementation of the National Technology Transfer and Advancement Act of 1995 (Public Law 104-113) through the sharing of standards management success stories, lessons learned, and emerging initiatives within the Executive Branch of the Federal Government. The target audience for this workshop included agency/department and contractor personnel and representatives of standards developing organizations that either used technical standards in their work for the Federal Government of participated in standards writing/management activities in support of the missions and programs of Federal agencies/departments. As with previous standards workshops sponsored by the DOE, views on the technical subject areas under the workshop theme were solicited from and provided by agency Standards Executives and standards program managers, voluntary standards organizations, and the private sector. This report includes vugraphs of the presentations.
Date: October 1998
Creator: unknown
Object Type: Article
System: The UNT Digital Library
3D Simulations of line emission from ICF capsules (open access)

3D Simulations of line emission from ICF capsules

Line emission from ICF implosions can be used to diagnose the temperature of the DT fuel and provides an indication of the distortion in the fuel-pusher interface. 2D simulations have provided valuable insights into the usefulness of argon and titanium dopants as diagnostics of instabilities. Characterizing the effects of drive asymmetries requires 3D modeling with large demands for computer time and memory, necessitating the use of parallel computers. We present the results of some 3D simulations achieved with a code utilizing both shared memory and distributed parallelism. We discuss the code structure and related performance issues.
Date: October 1, 1998
Creator: Langer, S.; Marinak, M. M. & Scott, H.
Object Type: Article
System: The UNT Digital Library
7th International Meshing Roundtable '98 (open access)

7th International Meshing Roundtable '98

The goal of the 7th International Meshing Roundtable is to bring together researchers and developers from industry, academia, and government labs in a stimulating, open environment for the exchange of technical information related to the meshing process. In the past, the Roundtable has enjoyed significant participation from each of these groups from a wide variety of countries.
Date: October 1, 1998
Creator: Eldred, T.J.
Object Type: Article
System: The UNT Digital Library
Accelerated Exposure Tests of Encapsulated Si Solar Cells and Encapsulation Materials (open access)

Accelerated Exposure Tests of Encapsulated Si Solar Cells and Encapsulation Materials

We have conducted a series of accelerated exposure test (AET) studies for various crystalline-Si (c-Si) and amorphous-Si (a-Si) cell samples that were encapsulated with different superstrates, pottants, and substrates. Nonuniform browning patterns of ethylene vinyl acetate (EVA) pottants were observed for glass/EVA/glass-encapsulated c-Si cell samples under solar simulator exposures at elevated temperatures. The polymer/polymer-configured laminates with Tedlar or Tefzel did not discolor because of photobleaching reactions, but yellowed with polyester or nylon top films. Delamination was observed for the polyester/EVA layers on a-Si minimodules and for a polyolefin-based thermoplastic pottant at high temperatures. For all tested c-Si cell samples, irregular changes in the current-voltage parameters were observed that could not be accounted for simply by the transmittance changes of the superstrate/pottant layers. Silicone-type adhesives used under UV-transmitting polymer top films were observed to cause greater cell current/efficiency loss than EVA or polyethylene pottants.
Date: October 8, 1998
Creator: Pern, F. J. & Glick, S. H.
Object Type: Article
System: The UNT Digital Library
Acceptable Knowledge Summary Report for Waste Stream: SR-T001-221F-HET/Drums (open access)

Acceptable Knowledge Summary Report for Waste Stream: SR-T001-221F-HET/Drums

Since beginning operations in 1954, the Savannah River Site FB-Line produced Weapons Grade Plutonium for the United States National Defense Program. The facility mission was mainly to process dilute plutonium solution received from the 221-F Canyon into highly purified plutonium metal. As a result of various activities (maintenance, repair, clean up, etc.) in support of the mission, the facility generated a transuranic heterogeneous debris waste stream. Prior to January 25, 1990, the waste stream was considered suspect mixed transuranic waste (based on potential for inclusion of F-Listed solvent rags/wipes) and is not included in this characterization. Beginning January 25, 1990, Savannah River Site began segregation of rags and wipes containing F-Listed solvents thus creating a mixed transuranic waste stream and a non-mixed transuranic waste stream. This characterization addresses the non-mixed transuranic waste stream packaged in 55-gallon drums after January 25, 1990.Characterization of the waste stream was achieved using knowledge of process operations, facility safety basis documentation, facility specific waste management procedures and storage / disposal records. The report is fully responsive to the requirements of Section 4.0 "Acceptable Knowledge" from the WIPP Transuranic Waste Characterization Quality Assurance Plan, CAO-94-1010, and provides a sound, (and auditable) characterization that satisfies the WIPP …
Date: October 26, 1998
Creator: Lunsford, G.F.
Object Type: Report
System: The UNT Digital Library
Accurate, finite-volume methods for 3D MHD on unstructured Lagrangian meshes (open access)

Accurate, finite-volume methods for 3D MHD on unstructured Lagrangian meshes

Previous 2D methods for magnetohydrodynamics (MHD) have contributed both to development of core code capability and to physics applications relevant to AGEX pulsed-power experiments. This strategy is being extended to 3D by development of a modular extension of an ASCI code. Extension to 3D not only increases complexity by problem size, but also introduces new physics, such as magnetic helicity transport. The authors have developed a method which incorporates all known conservation properties into the difference scheme on a Lagrangian unstructured mesh. Because the method does not depend on the mesh structure, mesh refinement is possible during a calculation to prevent the well known problem of mesh tangling. Arbitrary polyhedral cells are decomposed into tetrahedrons. The action of the magnetic vector potential, A {center_dot} {delta}l, is centered on the edges of this extended mesh. For ideal flow, this maintains {del} {center_dot} B = 0 to round-off error. Vertex forces are derived by the variation of magnetic energy with respect to vertex positions, F = {minus}{partial_derivative}W{sub B}/{partial_derivative}r. This assures symmetry as well as magnetic flux, momentum, and energy conservation. The method is local so that parallelization by domain decomposition is natural for large meshes. In addition, a simple, ideal-gas, finite pressure …
Date: October 1, 1998
Creator: Barnes, D. C. & Rousculp, C. L.
Object Type: Article
System: The UNT Digital Library
Active and passive computed tomography algorithm with a constrained conjugate gradient solution (open access)

Active and passive computed tomography algorithm with a constrained conjugate gradient solution

An active and passive computed tomographic technique (A&PCT) has been developed at the Lawrence Livermore National Laboratory (LLNL). The technique uses an external radioactive source and active tomography to map the attenuation within a waste drum as a function of mono-energetic gamma-ray energy. Passive tomography is used to localize and identify specific radioactive waste within the same container. The passive data is corrected for attenuation using the active data and this yields a quantitative assay of drum activity. A&PCT involves the development of a detailed system model that combines the data from the active scans with the geometry of the imaging system. Using the system model, iterative optimization techniques are used to reconstruct the image from the passive data. Requirements for high throughput yield measured emission levels in waste barrels that are too low to apply optimization techniques involving the usual Gaussian statistics. In this situation a Poisson distribution, typically used for cases with low counting statistics, is used to create an effective maximum likelihood estimation function. An optimization algorithm, Constrained Conjugate Gradient (CCG), is used to determine a solution for A&PCT quantitative assay. CCG, which was developed at LLNL, has proven to be an efficient and effective optimization method …
Date: October 1, 1998
Creator: Goodman, D.; Jackson, J. A.; Martz, H. E. & Roberson, G. P.
Object Type: Article
System: The UNT Digital Library
Active and passive computed tomography for nondestructive assay (open access)

Active and passive computed tomography for nondestructive assay

Traditional gamma-ray methods used to characterize nuclear waste introduce errors that are related to non-uniform measurement responses associated with unknown radioactive source and matrix material distributions. These errors can be reduced by applying an active and passive tomographic technique (A&PCT) developed at the Lawrence Livermore National Laboratory (LLNL). The technique uses an external radioactive source and active tomography to map the attenuation within a waste barrel as a function of mono-energetic gamma-ray energy. Passive tomography is used to localize and identify specific radioactive waste within the same container. Reconstruction of the passive data using the attenuation maps at specific energies allows internal waste radioactivity to be corrected for any overlying heterogeneous materials, thus yielding an absolute assay of the waste activity. LLNL and Bio-Imaging Research, Inc. have collaborated in a technology transfer effort to integrate an A&PCT assay system into a mobile waste characterization trailer. This mobile system has participated in and passed several formal DOE-sponsored performance demonstrations, tests and evaluations. The system is currently being upgraded with multiple detectors to improve throughput, automated gamma-ray analysis code to simplify the assay, and a new emission reconstruction code to improve accuracy
Date: October 28, 1998
Creator: Bernardi, R. T.; Camp, D. E.; Clard, D.; Jackson, J. A.; Martz, H. E.; Decman, D. J. et al.
Object Type: Article
System: The UNT Digital Library
Additional Development of a Dedicated Liquefied Petroleum Gas (LPG) Ultra Low Emissions Vehicle (ULEV) (open access)

Additional Development of a Dedicated Liquefied Petroleum Gas (LPG) Ultra Low Emissions Vehicle (ULEV)

This report describes the last in a series of three projects designed to develop a commercially competitive LPG light-duty passenger car that meets California ULEV standards and corporate average fuel economy (CAFE) energy efficiency guidelines for such a vehicle. In this project, IMPCO upgraded the vehicle's LPG vapor fuel injection system and performed emissions testing. The vehicle met the 1998 ULEV standards successfully, demonstrating the feasibility of meeting ULEV standards with a dedicated LPG vehicle.
Date: October 28, 1998
Creator: Technologies, IMPCO
Object Type: Report
System: The UNT Digital Library
Advanced composites technology (open access)

Advanced composites technology

The development of fiber composite components in next-generation munitions, such as sabots for kinetic energy penetrators and lightweight cases for advanced artillery projectiles, relies on design trade-off studies using validated computer code simulations. We are developing capabilities to determine the failure of advanced fiber composites under multiaxial stresses to critically evaluate three-dimensional failure models and develop new ones if necessary. The effects of superimposed hydrostatic pressure on failure of composites are being investigated using a high-pressure testing system that incorporates several unique features. Several improvements were made to the system this year, and we report on the first tests of both isotropic and fiber composite materials. The preliminary results indicate that pressure has little effect on longitudinal compression strength of unidirectional composites, but issues with obtaining reliable failures in these materials still remain to be resolved. The transverse compression strength was found to be significantly enhanced by pressure, and the trends observed for this property and the longitudinal strength are in agreement with recent models for failure of fiber composites.
Date: October 1, 1998
Creator: DeTeresa, S J; Groves, S E & Sanchez, R J
Object Type: Report
System: The UNT Digital Library
AN ADVANCED CONTROL SYSTEM FOR FINE COAL FLOTATION (open access)

AN ADVANCED CONTROL SYSTEM FOR FINE COAL FLOTATION

A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of tailings ash content. Then, based on an on-line estimate of incremental ash, the pulp level is adjusted using a model-based control algorithm to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the tenth quarter of this project, Task 6 (Equipment Procurement and Installation) was completed through the efforts of J.A. Herbst and Associates, Virginia Tech, Pittston Coal Company, and FGR Automation. As a result of this work, a model-based control system is now in place which can predict incremental ash based on tailings ash content and general plant data, and adjust pulp level accordingly to maintain a target incremental ash. Testing of this control system is expected to be carried out during the next quarter, and the results of this testing will be reported in the Eleventh Quarterly report. In addition, calibration of the video-based ash analyzer was continued and an extensive set of calibration data were obtained showing that the plant is running …
Date: October 25, 1998
Creator: unknown
Object Type: Report
System: The UNT Digital Library
ADVANCED EMISSIONS CONTROL DEVELOPMENT PROGRAM (open access)

ADVANCED EMISSIONS CONTROL DEVELOPMENT PROGRAM

The objective of this project is to develop practical strategies and systems for the simultaneous control of SO{sub 2}, NO{sub x}, particulate matter, and air toxics emissions from coal-fired boilers in such a way as to keep coal economically and environmentally competitive as a utility boiler fuel. Of particular interest is the control of air toxics emissions through the cost-effective use of conventional flue gas clean-up equipment such as electrostatic precipitators (ESP's), fabric filters (baghouses), and SO{sub 2} removal systems such as wet scrubbers and various clean coal technologies. This objective will be achieved through extensive development testing in the state-of-the art, 10 MW{sub e} equivalent, Clean Environment Development Facility (CEDF). The project has extended the capabilities of the CEDF to facilitate air toxics emissions control development work on backend flue gas cleanup equipment. Specifically, an ESP, a baghouse, and a wet scrubber for SO{sub 2} (and air toxics) control were added--all designed to yield air toxics emissions data under controlled conditions, and with proven predictability to commercial systems. A schematic of the CEDF and the project test equipment is shown in Figure 1. The specific objectives of the project are to: (1) Measure and understand production and partitioning of …
Date: October 1, 1998
Creator: Holmes, M.J.
Object Type: Report
System: The UNT Digital Library
Advanced Recovery and Integrated Extraction System (ARIES) Fiscal Year 1996 Annual Report (open access)

Advanced Recovery and Integrated Extraction System (ARIES) Fiscal Year 1996 Annual Report

President Clinton issued Nonprolferation and Export Control Policy in September 1993 in response to the growing threat of nuclear proliferation. Four months later, in January 1994, President Clinton and Russia's President Yeltsin issued a Joint Statement Between the United States and Russia on Nonprollfieration of Weapons of Mass Destruction and the Means of Their Delivery. President Clinton announced on 1 March 1995, that approximately 200 metric tons of US- origin weapons-usable fissile materials had been declared surplus to US defense needs. The Advanced Recovery and Integrated Extraction System (ARIES) Demonstration Project is one part of the scientific response to President Clinton's promise to reduce the nuclear weapons stockpile. The work accomplished on the ARIES Demonstration Project during fiscal year 1996, 10ctober 1995 through 30 September 1996, is described in this report. The Department of Energy (DOE), by forming the Office of Fissile Materials Disposition (OFMD), has initiated a Fissile Materials Disposition Program. The first step is the disassembly and conversion of weapons pits. Of the 200 metric tons of US surplus fissile material, approximately 50 tons are weapons plutonium, and of these 50 tons, 2/3 is contained in pits. Weapons plutonium wili be extracted from pits, rendered to an unclassified …
Date: October 1, 1998
Creator: Dennison, David; Massey, Pamela W. & Nelson, Timothy O.
Object Type: Report
System: The UNT Digital Library