Modeling of transient ionizing radiation effects in bipolar devices at high dose-rates (open access)

Modeling of transient ionizing radiation effects in bipolar devices at high dose-rates

To optimally design circuits for operation at high intensities of ionizing radiation, and to accurately predict their a behavior under radiation, precise device models are needed that include both stationary and dynamic effects of such radiation. Depending on the type and intensity of the ionizing radiation, different degradation mechanisms, such as photoelectric effect, total dose effect, or single even upset might be dominant. In this paper, the authors consider the photoelectric effect associated with the generation of electron-hole pairs in the semiconductor. The effects of low radiation intensity on p-II diodes and bipolar junction transistors (BJTs) were described by low-injection theory in the classical paper by Wirth and Rogers. However, in BJTs compatible with modem integrated circuit technology, high-resistivity regions are often used to enhance device performance, either as a substrate or as an epitaxial layer such as the low-doped n-type collector region of the device. Using low-injection theory, the transient response of epitaxial BJTs was discussed by Florian et al., who mainly concentrated on the effects of the Hi-Lo (high doping - low doping) epilayer/substrate junction of the collector, and on geometrical effects of realistic devices. For devices with highly resistive regions, the assumption of low-level injection is often …
Date: April 25, 2000
Creator: Fjeldly, T. A.; Deng, Y.; Shur, M. S.; Hjalmarson, Harold P. & Muyshondt, Arnoldo
Object Type: Article
System: The UNT Digital Library
Accelerating technology transfer from federal laboratories to the private sector by industrial R and D collaborations - A new business model (open access)

Accelerating technology transfer from federal laboratories to the private sector by industrial R and D collaborations - A new business model

Many important products and technologies were developed in federal laboratories and were driven initially by national needs and for federal applications. For example, the clean room technology that enhanced the growth of the semiconductor industry was developed at Sandia National Laboratories (SNL) decades ago. Similarly, advances in micro-electro-mechanical-systems (MEMS)--an important set of process technologies vital for product miniaturization--are occurring at SNL. Each of the more than 500 federal laboratories in the US, are sources of R and D that contributes to America's economic vitality, productivity growth and, technological innovation. However, only a fraction of the science and technology available at the federal laboratories is being utilized by industry. Also, federal laboratories have not been applying all the business development processes necessary to work effectively with industry in technology commercialization. This paper addresses important factors that federal laboratories, federal agencies, and industry must address to translate these under utilized technologies into profitable products in the industrial sector.
Date: April 13, 2000
Creator: Lombana, Cesar A.; Romig, Alton D.; Linton, Jonathan D. & Martinez, J. Leonard
Object Type: Article
System: The UNT Digital Library
Particulate briquetting technology for the steel industry: NICE3 (open access)

Particulate briquetting technology for the steel industry: NICE3

This report is a fact sheet on a new method for producing metallurgical furnace briquettes for the steel industry written for the NICE3 Program.
Date: April 10, 2000
Creator: National Renewable Energy Laboratory (U.S.)
Object Type: Book
System: The UNT Digital Library
TRANSVERSE POLARIZATION DISTRIBUTION AND FRAGMENTATION FUNCTIONS (open access)

TRANSVERSE POLARIZATION DISTRIBUTION AND FRAGMENTATION FUNCTIONS

The authors discuss transverse polarization distribution and fragmentation functions, in particular, T-odd functions with transverse momentum dependence, which might be relevant for the description of single transverse spin asymmetries. The role of intrinsic transverse momentum in the expansion in inverse powers of the hard scale is elaborated upon. The sin {phi} single spin asymmetry in the process e {rvec p} {r_arrow} e{prime} {pi}{sup +} X as recently reported by the HERMES Collaboration is investigated, in particular, by using the bag model.
Date: April 11, 2000
Creator: BOER,D.
Object Type: Article
System: The UNT Digital Library
A case study in modeling company policy documents as a source of requirements (open access)

A case study in modeling company policy documents as a source of requirements

This paper describes an approach that was developed to produce structured models that graphically reflect the requirements contained within a text document. The document used in this research is a draft policy document governing business in a research and development environment. In this paper, the authors present a basic understanding of why this approach is needed, the techniques developed, lessons learned during modeling and analysis, and recommendations for future investigation. The modeling method applied on the policy document was developed as an extension to entity relationship (ER) diagrams, which built in some structural information typically associated with object-oriented techniques. This approach afforded some structure as an analysis tool, while remaining flexible enough to be used with the text document. It provided a visual representation that allowed further analysis and layering of the model to be done.
Date: April 11, 2000
Creator: CRUMPTON,KATHLEEN MARIE; GONZALES,REGINA M. & TRAUTH,SHARON L.
Object Type: Article
System: The UNT Digital Library
Power for peace, prosperity, and the environment (open access)

Power for peace, prosperity, and the environment

The remarkable prosperity and standard of living enjoyed in the US is in large part linked to the use of energy. While high-energy use brings many benefits, it also causes environmental degradation. In the last decade, the potentially devastating effects of degradation of greenhouse gases have received worldwide attention. The tradeoff between sustaining a healthy environment and sustaining a healthy economy is a major challenge of the 21st century. In this paper, the authors explore some of the issues and focus particularly on the option of enhancing nuclear energy as a way to help sustain economic prosperity while decreasing pollution of the atmosphere.
Date: April 13, 2000
Creator: Eagan, Robert J.; Baker, Arnold B. & Sanders, Thomas L.
Object Type: Article
System: The UNT Digital Library
Wind powering America: Nebraska (open access)

Wind powering America: Nebraska

This fact sheet contains a description of Nebraska's wind energy resources and the state's green power programs. The fact sheet includes a list of contacts for those interested in obtaining more information.
Date: April 10, 2000
Creator: National Renewable Energy Laboratory (U.S.)
Object Type: Book
System: The UNT Digital Library
Salt Lake Clean Cities Coalition: Outstanding coalition director: Beverly Miller (Clean Cities alternative fuel information series fact sheet) (open access)

Salt Lake Clean Cities Coalition: Outstanding coalition director: Beverly Miller (Clean Cities alternative fuel information series fact sheet)

The Salt Lake metropolitan area faces some interesting economic and environmental challenges. It ranks eighth in the nation in population growth, so managing its increasing numbers without spoiling the beauty of its high mountain valley may seem to be a contradiction in goals. In addition, the 2002 Winter Olympics will attract almost 2 million visitors during February, when Salt Lake's unusual topography encourages its highest levels of air pollution. The Clean Cities Coalition is working with the Salt Lake Olympic Organizing Committee to find clean vehicles to transport visitors to and from the various Olympic venues. A major goal of the Coalition is to keep as many AFVs as possible in Utah after the Olympics.
Date: April 26, 2000
Creator: Woodward, S.
Object Type: Book
System: The UNT Digital Library
Biodiesel: The clean, green fuel for diesel engines (fact sheet) (open access)

Biodiesel: The clean, green fuel for diesel engines (fact sheet)

Natural, renewable resources such as vegetable oils and recycled restaurant greases can be chemically transformed into clean-burning biodiesel fuels. As its name implies, biodiesel is like diesel fuel except that it's organically produced. It's also safe for the environment, biodegradable, and produces significantly less air pollution than diesel fuel.
Date: April 11, 2000
Creator: Tyson, K.S.
Object Type: Book
System: The UNT Digital Library
Continued study of the time stability of a small water Cerenkov detector (open access)

Continued study of the time stability of a small water Cerenkov detector

This note describes continued studies at Fermilab of the long term stability of a small water Cerenkov tank. Previous results are presented for studies between November, 1997 and October, 1998. The data given here continue these measurements through December, 1998, when the tank and electronics were moved to a different location, and then to November, 1999. The water tank, bag liner, water, photomultiplier tube, and data acquisition software were unchanged for the additional measurements from June to November, 1999. However, some details of the geometry of the trigger counters relative to the tank and of the electronics may have differed. The setup for the 1999 results is described in this note. The same analog-to-digital converter (ADC) was used for both time periods. Its pedestal was quite stable during the 1997--1998 measurements, but sizeable changes were observed in the more recent runs. As a result, dedicated pedestal runs were performed, and a number of additional tests were conducted.
Date: April 3, 2000
Creator: Strom, D.; Glass, H.; Spinka, H. & Thomure, M.
Object Type: Report
System: The UNT Digital Library
NREL Information Resources Catalogue 1999 (open access)

NREL Information Resources Catalogue 1999

This is the sixth annual catalogue listing documents produced by NREL during the last fiscal year. Each year the catalogue is mailed to state energy offices, DOE support offices, and to anyone looking to find out more information about NREL's activities and publications.
Date: April 3, 2000
Creator: unknown
Object Type: Book
System: The UNT Digital Library
Grain boundary dissipation in high-{Tc} superconductors (open access)

Grain boundary dissipation in high-{Tc} superconductors

Thin-film and bulk [001] tilt bicrystal grain boundaries (GBs) in YBa{sub 2}Cu{sub 3}O{sub 7} exhibit a strong dependence of critical current density, J{sub c} on misorientation angle. What was initially difficult to understand was the 30x smaller J{sub c} in bulk GBs which are microscopically more perfect. The authors review an explanation of this zero-field data, which is based on the pinning of Josephson vortices by the meandering found in thin-film GBs. In addition, there is evidence that J{sub c} of GBs does not drop as quickly with applied magnetic field as expected by simple Josephson junction models. The long-wavelength pinning potential due to meandering is less effective at high fields, but Gurevich and Cooley (GC) proposed a new mechanism for an enhanced GB J{sub c} arising from pinned Abrikosov vortices in the banks of a GB which present a static, quasiperiodic pinning potential to pin GB vortices. They find a peak in J{sub c} and an unusual hysteresis which give considerable support to the GC concept. In low fields, the GBs exhibit a larger J{sub c} for field cooling, which is opposite to the usual hysteresis but agrees with GC due to the larger Abrikosov vortex density in the …
Date: April 3, 2000
Creator: Gray, K. E.; Miller, D. J.; Field, M. B.; Kim, D. H. & Berghuis, P.
Object Type: Article
System: The UNT Digital Library
Module 30 year life: What does it mean and is it predictable-achievable? (open access)

Module 30 year life: What does it mean and is it predictable-achievable?

The authors define what they mean by a 30-year module life and the testing protocol that they believe is involved in achieving such a prediction. However, they do not believe that a universal test (or series of tests) will allow for such a prediction to be made. They can test for a lot of things, but they believe it is impossible to provide a 30-year certification for any PV module submitted for test. They explain their belief in this paper.
Date: April 11, 2000
Creator: Mcmahon, T. J.; Jorgensen, G. J.; Hulstrom, R. L.; King, David L. & Quintana, Michael A.
Object Type: Article
System: The UNT Digital Library
Hanford tank waste simulants specification and their applicability for the retrieval, pretreatment, and vitrification processes (open access)

Hanford tank waste simulants specification and their applicability for the retrieval, pretreatment, and vitrification processes

A wide variety of waste simulants were developed over the past few years to test various retrieval, pretreatment and waste immobilization technologies and unit operations. Experiments can be performed cost-effectively using non-radioactive waste simulants in open laboratories. This document reviews the composition of many previously used waste simulants for remediation of tank wastes at the Hanford reservation. In this review, the simulants used in testing for the retrieval, pretreatment, and vitrification processes are compiled, and the representative chemical and physical characteristics of each simulant are specified. The retrieval and transport simulants may be useful for testing in-plant fluidic devices and in some cases for filtration technologies. The pretreatment simulants will be useful for filtration, Sr/TRU removal, and ion exchange testing. The vitrification simulants will be useful for testing melter, melter feed preparation technologies, and for waste form evaluations.
Date: April 4, 2000
Creator: Golcar, G. R.; Colton, N. G.; Darab, J. G. & Smith, H. D.
Object Type: Report
System: The UNT Digital Library
Polymethylsilsesquioxanes Through Base-Catalyzed Redistribution of Oligomethylhydridosiloxanes (open access)

Polymethylsilsesquioxanes Through Base-Catalyzed Redistribution of Oligomethylhydridosiloxanes

There has been an increasing amount of interest in silsesquioxanes and polysilsesquioxanes. They have been used as models for silica surfaces and have been shown to have great potential for several industrial applications. Typical synthesis of polysilsesquioxanes involves the hydrolysis of organotricholorosilanes and/or organotrialkoxysilanes in the presence of acid or base catalysts, usually in the presence of organic solvents.
Date: April 4, 2000
Creator: Rahimian, Kamyar; Assink, Roger A. & Loy, Douglas A.
Object Type: Article
System: The UNT Digital Library
Keys to successful D and D technology Deployments at the INEEL (open access)

Keys to successful D and D technology Deployments at the INEEL

Seven improved decontamination and decommissioning (D&D) technologies were successfully deployed at the Idaho National Engineering and Environmental Laboratory (INEEL) during the Accelerated Site Technology Deployment (ASTD) Integrated Decontamination and Decommissioning (ID&D) project. The use of these improved technologies saved the INEEL $462K in fiscal year 1999, and is projected to save about $14M over the next ten years. Since deploying new technologies on D&D projects shows great potential for cost-savings, factors that led to successful deployment have been documented. These factors are described here as they apply to the seven deployments at the INEEL to assist with deployments at other DOE sites.
Date: April 2, 2000
Creator: Smith, A. M.; Meservey, R. H. & Shoemaker, H.
Object Type: Article
System: The UNT Digital Library
Wind powering America: Minnesota (open access)

Wind powering America: Minnesota

This fact sheet contains a description of Minnesota's wind energy resources, and the state's green power and net metering programs as well as financial incentives that support the programs. The fact sheet includes a list of contacts for those interested in obtaining more information.
Date: April 10, 2000
Creator: National Renewable Energy Laboratory (U.S.)
Object Type: Book
System: The UNT Digital Library
Simulation of Npn and Pnp AlGaN/GaN heterojunction bipolar transistors performances: Limiting factors and optimum design (open access)

Simulation of Npn and Pnp AlGaN/GaN heterojunction bipolar transistors performances: Limiting factors and optimum design

The performance capabilities of Npn and Pnp AlGaN/GaN heterojunction bipolar transistors have been investigated by using a drift-diffusion transport model. Numerical results have been employed to study the effect of the p-type Mg doping and its incomplete ionization on device performance. The high base resistance induced by the deep acceptor level is found to be the cause of limited current gain values for Npn devices. Several computation approaches have been considered to improve their performance. Reasonable improvement of the DC current gain {beta} is observed by realistically reducing the base thickness in accordance with processing limitations. Base transport enhancement is also predicted by the introduction of a quasi-electric field in the base. The impact of the base resistivity on high-frequency characteristics is investigated for Npn AlGaN/GaN devices. Optimized predictions with maximum oscillation frequency value as high as f{sub MAX} = 20 GHz and a unilateral power gain--U = 25 dB make this bipolar GaN-based technology compatible with communication applications. Simulation results reveal that the restricted amount of free carriers from the p-doped emitter limits Pnp's DC performances operating in common emitter configuration. A preliminary analysis of r.f. characteristics for the Pnp counterpart indicates limited performance mainly caused by the degraded …
Date: April 25, 2000
Creator: MONIER,C.; REN,F.; HAN,JUNG; CHANG,PING-CHIH; SHUL,RANDY J.; LEE,K.P. et al.
Object Type: Article
System: The UNT Digital Library
Advanced Reservoir Characterization in the Antelope Shale to Establish the Viability of CO2 Enhanced Oil Recovery in California's Monterey Formation Siliceous Shales, Class III (open access)

Advanced Reservoir Characterization in the Antelope Shale to Establish the Viability of CO2 Enhanced Oil Recovery in California's Monterey Formation Siliceous Shales, Class III

The primary objective of this project was to conduct advanced reservoir characterization and modeling studies in the Antelope Shale of the Bureau Vista Hills Field. Work was subdivided into two phases or budget periods. The first phase of the project focused on a variety of advanced reservoir characterization techniques to determine the production characteristics of the Antelope Shale reservoir. Reservoir models based on the results of the characterization work would then be used to evaluate how the reservoir would respond to enhanced oil recovery (EOR) processes such as of CO2 flooding. The second phase of the project would be to implement and evaluate a CO2 in the Buena Vista Hills Field. A successful project would demonstrate the economic viability and widespread applicability of CO2 flooding in siliceous shale reservoirs of the San Joaquin Valley.
Date: April 24, 2000
Creator: Perri, Pasquale R.; Cooney, John; Fong, Bill; Julander, Dale; Marasigan, Aleks; Morea, Mike et al.
Object Type: Report
System: The UNT Digital Library
QCD AT HIGH PARTON DENSITY (open access)

QCD AT HIGH PARTON DENSITY

The authors derive an equation determining the small-x evolution of the F{sub 2} structure function of a large nucleus which resumes a cascade of gluons in the leading logarithmic approximation using Mueller's color dipole model. In the traditional language it corresponds to resummation of the pomeron fan diagrams, originally conjectured in the GLR equation. The authors show that the solution of the equation describes the physics of structure functions at high partonic densities, thus allowing them to gain some understanding of the most interesting and challenging phenomena in small-x physics--saturation.
Date: April 25, 2000
Creator: KOVCHEGOV,Y.V.
Object Type: Article
System: The UNT Digital Library
Registration of range data using a hybrid simulated annealing and iterative closest point algorithm (open access)

Registration of range data using a hybrid simulated annealing and iterative closest point algorithm

The need to register data is abundant in applications such as: world modeling, part inspection and manufacturing, object recognition, pose estimation, robotic navigation, and reverse engineering. Registration occurs by aligning the regions that are common to multiple images. The largest difficulty in performing this registration is dealing with outliers and local minima while remaining efficient. A commonly used technique, iterative closest point, is efficient but is unable to deal with outliers or avoid local minima. Another commonly used optimization algorithm, simulated annealing, is effective at dealing with local minima but is very slow. Therefore, the algorithm developed in this paper is a hybrid algorithm that combines the speed of iterative closest point with the robustness of simulated annealing. Additionally, a robust error function is incorporated to deal with outliers. This algorithm is incorporated into a complete modeling system that inputs two sets of range data, registers the sets, and outputs a composite model.
Date: April 17, 2000
Creator: LUCK,JASON; LITTLE,CHARLES Q. & HOFF,WILLIAM
Object Type: Article
System: The UNT Digital Library
Unusual magnetic quantum oscillations in organic metals at high magnetic fields (open access)

Unusual magnetic quantum oscillations in organic metals at high magnetic fields

The authors report on Shubnikov-de Haas (SdH) and de Haas-van Alphen (dHvA) results for the highly two-dimensional (2D) organic superconductors {kappa}-(ET){sub 2}I{sub 3} ({Tc} = 3.5 K) and {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} ({Tc} = 4.4 K). The SdH oscillations of both materials show an apparent deviation from the well-understood 2D dHvA signal at low temperatures and high magnetic fields. For {kappa}-(ET){sub 2}I{sub 3}, the mechanism leading to this behavior still needs to be clarified. For {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3}, an anomalous steady background part of the magnetoresistance seems to account for the observed discrepancies.
Date: April 4, 2000
Creator: Wosnitza, J.; Wanka, S.; Hagel, J.; Qualls, J. S.; Brooks, J. S.; Balthes, E. et al.
Object Type: Article
System: The UNT Digital Library
A New Class of High Force, Low-Voltage, Compliant Actuation System (open access)

A New Class of High Force, Low-Voltage, Compliant Actuation System

Although many actuators employing electrostatic comb drives have been demonstrated in a laboratory environment, widespread acceptance in mass produced microelectromechanical systems (MEMS) may be limited due to issues associated with low drive force, large real estate demands, high operating voltages, and reliability concerns due to stiction. On the other hand, comb drives require very low drive currents, offer predictable response, and are highly compatible with the fabrication technology. The expand the application space and facilitate the widespread deployment of self-actuated MEMS, a new class of advanced actuation systems has been developed that maintains the highly desirable aspects of existing components, while significantly diminishing the issues that could impede large scale acceptance. In this paper, the authors will present low-voltage electrostatic actuators that offer a dramatic increase in force over conventional comb drive designs. In addition, these actuators consume only a small fraction of the chip area previously used, yielding significant gains in power density. To increase the stroke length of these novel electrostatic actuators, the authors have developed highly efficient compliant stroke amplifiers. The coupling of compact, high-force actuators with fully compliant displacement multipliers sets a new paradigm for highly integrated microelectromechanical systems.
Date: April 10, 2000
Creator: Rodgers, M. Steven; Kota, Sridhar; Hetrick, Joel; Li, Zhe; Jensen, Brian D.; Krygowski, Thomas W. et al.
Object Type: Article
System: The UNT Digital Library
Density functional theory of simple polymers in a slit pore: 3. Surface tension (open access)

Density functional theory of simple polymers in a slit pore: 3. Surface tension

In a previous study of tangent site chains near a surface, the inhomogeneous density profiles were found through Density Functional theory. In the current study, the surface tensions of these systems are found from the results of the previous study through a thermodynamic integration. The calculated surface tensions are then compared to those found directly through computer simulation. Both the surface tension and surface excess for polymeric systems are shown to qualitatively differ from those of atomic systems, although certain similarities are seen at high densities.
Date: April 4, 2000
Creator: HOOPER,JUSTIN B.; MCCOY,JOHN D.; CURRO,JOHN G. & VAN SWOL,FRANK B.
Object Type: Article
System: The UNT Digital Library