European Security: The Debate in NATO and the European Union (open access)

European Security: The Debate in NATO and the European Union

This report reviews progress within NATO to develop a European Security and Defense Identity (ESDI), and the initiative within the European Union to create a common European Security and Defense Policy (ESDP). The report considers both European and U.S. perspectives on these developments. It will be updated as events warrant.
Date: April 25, 2000
Creator: Donfried, Karen & Gallis, Paul E.
Object Type: Report
System: The UNT Digital Library
Transit Grants: Department of Labor's Certification Process (open access)

Transit Grants: Department of Labor's Certification Process

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed its preliminary observations on the timeliness of the Department of Labor's (DOL) certification process for transit grants, focusing on: (1) DOL's process for issuing certifications for grant applications; (2) how DOL defines and calculates how long it takes to issue certifications; and (3) the trends and factors affecting the length of DOL's certification process."
Date: April 25, 2000
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Nuclear Safety: Concerns With the Continuing Operation of Soviet-Designed Nuclear Power Reactors (open access)

Nuclear Safety: Concerns With the Continuing Operation of Soviet-Designed Nuclear Power Reactors

A chapter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on Soviet-designed nuclear power reactors, focusing on: (1) how much money has been spent by the United States and other countries for assistance to improve the safety of Soviet-designed nuclear power reactors--and the types of assistance being provided--as well as planned U.S. expenditures; (2) experts' views on the impact of the assistance; (3) the status of efforts to close high-risk Soviet-designed reactors; and (4) the management of the Department of Energy's (DOE) and the Nuclear Regulatory Commission's (NRC) safety assistance activities."
Date: April 25, 2000
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
SBA Loan Monitoring System: Substantial Progress Yet Key Risks and Challenges Remain (open access)

SBA Loan Monitoring System: Substantial Progress Yet Key Risks and Challenges Remain

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Small Business Administration's (SBA) progress in performing planning actions for its loan monitoring system."
Date: April 25, 2000
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Unmanned Aerial Vehicles: Progress of the Global Hawk Advanced Concept Technology Demonstration (open access)

Unmanned Aerial Vehicles: Progress of the Global Hawk Advanced Concept Technology Demonstration

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the Global Hawk Advanced Concept Technology Demonstration, focusing on: (1) whether the average unit flyaway price for the 10 Global Hawk production aircraft numbered 11 through 20 will be within the Department of Defense's (DOD) price goal of $10 million each in fiscal year 1994 dollars; (2) the status of the military user demonstration, including the extent to which Global Hawk has demonstrated reconnaissance capabilities; and (3) DOD and Air Force plans to transition to a formal acquisition program."
Date: April 25, 2000
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Federal Research: DOE Is Providing Independent Review of the Scientific Merit of Its Research (open access)

Federal Research: DOE Is Providing Independent Review of the Scientific Merit of Its Research

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on the Department of Energy's (DOE) merit review practices, focusing on: (1) what procedures DOE has established for performing merit reviews; and (2) whether DOE could document that it has followed the merit review procedures it has established."
Date: April 25, 2000
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Characterization and decant of Tank 42H sludge sample ESP-200 (open access)

Characterization and decant of Tank 42H sludge sample ESP-200

DWPF Engineering requested that the Savannah River Technology Center (SRTC) provide a demonstration of the DWPF flowsheet on sludge from Tank 42H in the Shielded Cell facility. A 5 liter sample of the Tank 42H sludge (ESP-200), obtained with the tank contents fully mixed, arrived at SRTC on January 20, 1998. This report details receipt of the 5 liter sample at SRTC, the decant of the sample, and the characterization of the pre- and post-decant Tank 42H sludge. Evaluation of the measured composition of the supernate indicates Sample ESP-200 became diluted approximately 20 percent by volume prior to receipt. This dilution complicates the relationship of the characterization of Post-Decant ESP-200 to the current contents of Tank 42H. For the purposes of modeling the current tank contents of Tank 42H, this report provides an estimated composition based on analytical data of recent samples from Tank 42H.
Date: April 25, 2000
Creator: Hay, M.S.
Object Type: Report
System: The UNT Digital Library
Corrosion detection in multi-layered rotocraft structures (open access)

Corrosion detection in multi-layered rotocraft structures

Rotorcraft structures do not readily lend themselves to quantifiable inspection methods due to airframe construction techniques. Periodic visual inspections are a common practice for detecting corrosion. Unfortunately, when the telltale signs of corrosion appear visually, extensive repair or refurbishment is required. There is a need to nondestructively evaluate airframe structures in order to recognize and quantify corrosion before visual indications are present. Nondestructive evaluations of rotorcraft airframes face inherent problems different from those of the fixed wing industry. Most rotorcraft lap joints are very narrow, contain raised fastener heads, may possess distortion, and consist of thinner gage materials ({approximately}0.012--0.125 inches). In addition the structures involve stack-ups of two and three layers of thin gage skins that are separated by sealant of varying thickness. Industry lacks the necessary data techniques, and experience to adequately perform routine corrosion inspection of rotorcraft. In order to address these problems, a program is currently underway to validate the use of eddy current inspection on specific rotorcraft lap joints. Probability of detection (POD) specimens have been produced that simulate two lap joint configurations on a model TH-57/206 helicopter. The FAA's Airworthiness Assurance Center (AANC) at Sandia Labs and Bell Helicopter have applied single and dual frequency …
Date: April 25, 2000
Creator: ROACH,DENNIS P.; WALKINGTON,PHILLIP D.; HOHMAN,ED & MARSHALL,GREG
Object Type: Article
System: The UNT Digital Library
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
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
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
Application of finite element, global polynomial, and kriging response surfaces in Progressive Lattice Sampling designs (open access)

Application of finite element, global polynomial, and kriging response surfaces in Progressive Lattice Sampling designs

This paper examines the modeling accuracy of finite element interpolation, kriging, and polynomial regression used in conjunction with the Progressive Lattice Sampling (PLS) incremental design-of-experiments approach. PLS is a paradigm for sampling a deterministic hypercubic parameter space by placing and incrementally adding samples in a manner intended to maximally reduce lack of knowledge in the parameter space. When combined with suitable interpolation methods, PLS is a formulation for progressive construction of response surface approximations (RSA) in which the RSA are efficiently upgradable, and upon upgrading, offer convergence information essential in estimating error introduced by the use of RSA in the problem. The three interpolation methods tried here are examined for performance in replicating an analytic test function as measured by several different indicators. The process described here provides a framework for future studies using other interpolation schemes, test functions, and measures of approximation quality.
Date: April 25, 2000
Creator: Romero, Vincent J.; Swiler, Laura Painton & Giunta, Anthony A.
Object Type: Article
System: The UNT Digital Library
Reexamination of spent fuel shipment risk estimates (open access)

Reexamination of spent fuel shipment risk estimates

The risks associated with the transport of spent nuclear fuel by truck and rail have been reexamined and compared to results published in NUREG-O170 and the Modal Study. The full reexamination considered transport of PWR and BWR spent fuel by truck and rail in four generic Type B spent fuel casks. Because they are typical, this paper presents results only for transport of PWR spent fuel in steel-lead steel casks. Cask and spent fuel response to collision impacts and fires were evaluated by performing three-dimensional finite element and one-dimensional heat transport calculations. Accident release fractions were developed by critical review of literature data. Accident severity fractions were developed from Modal Study truck and rail accident event trees, modified to reflect the frequency of occurrence of hard and soft rock wayside route surfaces as determined by analysis of geographic data. Incident-free population doses and the population dose risks associated with the accidents that might occur during transport were calculated using the RADTRAN 5 transportation risk code. The calculated incident-free doses were compared to those published in NUREG-O170. The calculated accident dose risks were compared to dose risks calculated using NUREG-0170 and Modal Study accident source terms. The comparisons demonstrated that both …
Date: April 25, 2000
Creator: Cook, J. R. & Sprung, Jeremy L.
Object Type: Article
System: The UNT Digital Library
A note on the transition from coupled plasticity and damage to decohesion in the evolution of solder failure (open access)

A note on the transition from coupled plasticity and damage to decohesion in the evolution of solder failure

A key issue of solder joint reliability is joint failure due to thermomechanical fatigue (TMF). TMF is caused by different coefficients of thermal expansion (CTEs) of the materials in an electronic package, combined with changes in the ambient temperature. Different CTEs result in cyclical strain in the assembly, and this strain is concentrated almost entirely in the solder because it is the most deformable portion of the package. Since solder alloy is at a significant fraction of its melting point even at room temperature, the cyclical strain enhances mass diffusion and causes dramatic changes in the alloy microstructure over time. As the microstructure changes and becomes coarser, the solder alloy weakens and eventually microcracks nucleate and grow in the joint, leading to component failure. the failure of solder joints is difficult to detect due to the inert nature of the electrical system. If the system is not on for extended periods then failures can not be observed. Therefore it is important to develop an advanced predictive capability which allows scientists and engineers to predict solder degradation and identify reliability problems in aging electronics early.
Date: April 25, 2000
Creator: Chen, Zhen & Fang, Huei Eliot
Object Type: Article
System: The UNT Digital Library
Minimum-time control of systems with Coloumb friction: Near global optima via mixed integer linear programming (open access)

Minimum-time control of systems with Coloumb friction: Near global optima via mixed integer linear programming

This work presents a method of finding near global optima to minimum-time trajectory generation problem for systems that would be linear if it were not for the presence of Coloumb friction. The required final state of the system is assumed to be maintainable by the system, and the input bounds are assumed to be large enough so that they can overcome the maximum static Coloumb friction force. Other than the previous work for generating minimum-time trajectories for non redundant robotic manipulators for which the path in joint space is already specified, this work represents, to the best of the authors' knowledge, the first approach for generating near global optima for minimum-time problems involving a nonlinear class of dynamic systems. The reason the optima generated are near global optima instead of exactly global optima is due to a discrete-time approximation of the system (which is usually used anyway to simulate such a system numerically). The method closely resembles previous methods for generating minimum-time trajectories for linear systems, where the core operation is the solution of a Phase I linear programming problem. For the nonlinear systems considered herein, the core operation is instead the solution of a mixed integer linear programming problem.
Date: April 25, 2000
Creator: Driessen, Brian & Sadegh, Nader
Object Type: Article
System: The UNT Digital Library
Scalable rendering on PC clusters (open access)

Scalable rendering on PC clusters

This case study presents initial results from research targeted at the development of cost-effective scalable visualization and rendering technologies. The implementations of two 3D graphics libraries based on the popular sort-last and sort-middle parallel rendering techniques are discussed. An important goal of these implementations is to provide scalable rendering capability for extremely large datasets (>> 5 million polygons). Applications can use these libraries for either run-time visualization, by linking to an existing parallel simulation, or for traditional post-processing by linking to an interactive display program. The use of parallel, hardware-accelerated rendering on commodity hardware is leveraged to achieve high performance. Current performance results show that, using current hardware (a small 16-node cluster), they can utilize up to 85% of the aggregate graphics performance and achieve rendering rates in excess of 20 million polygons/second using OpenGL{reg_sign} with lighting, Gouraud shading, and individually specified triangles (not t-stripped).
Date: April 25, 2000
Creator: Wylie, Brian N.; Lewis, Vasily; Shirley, David Noyes & Pavlakos, Constantine
Object Type: Article
System: The UNT Digital Library
Surety of human elements of high consequence systems: An organic model (open access)

Surety of human elements of high consequence systems: An organic model

Despite extensive safety analysis and application of safety measures, there is a frequent lament, ``Why do we continue to have accidents?'' Two breakdowns are prevalent in risk management and prevention. First, accidents result from human actions that engineers, analysts and management never envisioned and second, controls, intended to preclude/mitigate accident sequences, prove inadequate. This paper addresses the first breakdown, the inability to anticipate scenarios involving human action/inaction. The failure of controls has been addressed in a previous publication (Forsythe and Grose, 1998). Specifically, this paper presents an approach referred to as surety. The objective of this approach is to provide high levels of assurance in situations where potential system failure paths cannot be fully characterized. With regard to human elements of complex systems, traditional approaches to human reliability are not sufficient to attain surety. Consequently, an Organic Model has been developed to account for the organic properties exhibited by engineered systems that result from human involvement in those systems.
Date: April 25, 2000
Creator: FORSYTHE,JAMES C. & WENNER,CAREN A.
Object Type: Article
System: The UNT Digital Library
Screening Analysis for EPACT-Covered Commercial HVAC and Water-Heating Equipment (open access)

Screening Analysis for EPACT-Covered Commercial HVAC and Water-Heating Equipment

The Energy Policy and Conservation Act (EPCA) as amended by the Energy Policy Act of 1992 (EPACT) establishes that the U.S. Department of Energy (DOE) regulate efficiency levels of certain categories of commercial heating, cooling, and water-heating equipment. EPACT establishes the initial minimum efficiency levels for products falling under these categories, based on ASHRAE/IES Standard 90.1-1989 requirements. EPCA states that, if ASHRAE amends Standard 90.1-1989 efficiency levels, then DOE must establish an amended uniform national manufacturing standard at the minimum level specified in the amended Standard 90.1 and that it can establish higher efficiency levels if they would result in significant additional energy savings. 011Standard 90.1-1999 increases minimum efficiency levels for some of the equipment categories covered by EPCA 92. DOE conducted a screening analysis to determine the energy-savings potential for EPACT-covered products meet and exceeding these levels. This paper describes the methodology, data assumptions, and results of the analysis.
Date: April 25, 2000
Creator: Somasundaram, Sriram; Armstrong, Peter R; Belzer, David B; Gaines, Suzanne C; Hadley, Donald L; Smith, David L et al.
Object Type: Report
System: The UNT Digital Library
Hydrostatic Mooring System (open access)

Hydrostatic Mooring System

This report is a summary of the following topics of the first quarter of 2000: (1) Han Padron Associates (HPA) provided conceptual structural design of the mooring buoy; and (2) they completed partial review of the HPA design and designed the sealing elements.
Date: April 25, 2000
Creator: Jens Korsgaard
Object Type: Report
System: The UNT Digital Library
Current issues in prompt photon production (open access)

Current issues in prompt photon production

The authors give a brief account of recent theoretical developments in prompt photon production.
Date: April 25, 2000
Creator: Laenen, E.; Sterman, G. & Vogelsang, W.
Object Type: Article
System: The UNT Digital Library
Prompt Photon Production in Polarized Hadron Collisions. (open access)

Prompt Photon Production in Polarized Hadron Collisions.

We consider spin asymmetries for prompt photon production in collisions of longitudinally polarized hadrons. This reaction will be a key tool at the BNL-RHIC {rvec p}{rvec p} collider for determining the gluon spin density in a polarized proton. We study the effects of QCD corrections, such as all-order soft-gluon ''threshold'' resummations.
Date: April 25, 2000
Creator: Vogelsang, W.
Object Type: Article
System: The UNT Digital Library
Power Line Damage, Electrical Outages Reduced in the ''Sleet Belt'': NICE3 Steel Project Fact Sheet (open access)

Power Line Damage, Electrical Outages Reduced in the ''Sleet Belt'': NICE3 Steel Project Fact Sheet

The AR Windamper System was developed through a grant from the Inventions and Innovation Program, to protect power transmission lines in sleet belt states and provinces by eliminating the ''galloping'' phenomenon. Wind damping products minimize power outages and reduce repair costs to transmission lines.
Date: April 25, 2000
Creator: unknown
Object Type: Book
System: The UNT Digital Library
Environmental Assessment and Finding of No Significant Impact: Transfer of the Department of Energy Grand Junction Office to Non-DOE Ownership (open access)

Environmental Assessment and Finding of No Significant Impact: Transfer of the Department of Energy Grand Junction Office to Non-DOE Ownership

The scope of this environmental assessment (EA) is to analyze the potential consequences of the Proposed Action on human health and the environment. Accordingly, this EA contains an introduction to the site and the history of the Grand Junction Office (Chapter One), a description of the Purpose and Need for Agency Action (Chapter Two), a description of the Proposed Action and Alternatives (Chapter Three), and the description of the Affected Environment and the Environmental Consequences (Chapter Four). Resource categories addressed in this EA include geology, soils and topography, groundwater and surface water, floodplains and wetlands, land use and infrastructure, human health, ecological resources, cultural resources, air quality, noise, visual resources, solid and hazardous waste management, transportation, and socioeconomic and environmental justice.
Date: April 25, 2000
Creator: unknown
Object Type: Report
System: The UNT Digital Library
IRIS Program. Second quarterly report (open access)

IRIS Program. Second quarterly report

None
Date: April 25, 2000
Creator: Carelli, M. D.
Object Type: Report
System: The UNT Digital Library