Novel Processing of 81-mm Cu Shaped Charge Liners (open access)

Novel Processing of 81-mm Cu Shaped Charge Liners

A seven-step procedure was developed for producing shaped charge liner blanks by back extrusion at liquid nitrogen temperatures. Starting with a 38.1-mm diameter, 101.6-mm long cylinder at 77K, three forging steps with a flat-top die are required to produce the solid cone while maintaining low temperature. The solid cone is forged in four individual back extrusions at 77K to produce the rough liner blank. This procedure is capable of being run in batch processes to improve the time efficiency.
Date: January 16, 2002
Creator: Schwartz, A & Korzekwa, D
Object Type: Report
System: The UNT Digital Library
Microstructural Origins of Dynamic Fracture in Ductile Metals (open access)

Microstructural Origins of Dynamic Fracture in Ductile Metals

From the formation of microscopic cracks in the fuel pipe liner of the space shuttle to the safety of roadway bridges, the fracture of materials has enormous implications throughout our society. The ability to assess and design safe engineering structures requires a detailed knowledge of this failure process. The fracture process depends on both the loading history and the detailed microscopic structure (microstructure) of the material. Weak points, such as inclusions and grain boundary junctions, are the locations from which microscopic fractures (voids and cracks) originate. Once nucleated, these fractures quickly link together to form a macroscopic crack. Despite this qualitative understanding, little is known about voids nucleation, plastic deformation in the surrounding material, and the mechanisms of linking. Central to Stockpile Stewardship is an understanding of shock loading of materials. During the passage of a shock wave, the material is compressed at a very high rate. This compression produces a high density of dislocation defects and other changes to the microstructure that are poorly understood. When the shock wave reflects from a free surface, the compression is rapidly released and extreme tension is produced inside the material. If this tension exceeds the internal rupture strength, microscopic fractures form and …
Date: December 16, 2002
Creator: Becker, R; Belak, J & Campbell, G
Object Type: Report
System: The UNT Digital Library
Fishery, Aquaculture, and Marine Mammal Legislation in the 107th Congress (open access)

Fishery, Aquaculture, and Marine Mammal Legislation in the 107th Congress

This report provides the information related to the fishery, aquaculture, and marine mammal issues in the 107th Congress
Date: September 16, 2002
Creator: Buck, Eugene H.
Object Type: Report
System: The UNT Digital Library
Shear Localization and Fracture in Shocked Metals (open access)

Shear Localization and Fracture in Shocked Metals

Metals are used in structural engineering applications because they can yield and deform before they break. However, under certain conditions of dynamic loading, metals can fail prematurely. This behavior is often associated with shear localization phenomena, with a shear band acting as a precursor to crack formation. These phenomena have been observed in metals for some time, however modeling this behavior in a continuum simulation code has met with very limited success. We are pursuing a series of model experiments closely linked to new model development in order to gain a fundamental understanding of shear localization and fracture. Many NNSA and DoD related missions require modeling and simulation of the response of metals to high explosive (HE) loading and whether those metals fail or fracture. HE loading differs from the loading experienced by a specimen in a traditional engineering application. In HE loading, the first process to occur is the passage of a strong shock through the metal due to detonation. This shock completely changes the microstructure of the metal by inducing intense dislocation multiplication, sometimes accompanied by the formation of deformation twins. This change in microstructure strongly modifies the mechanical response of the metal, changing its yield strength, work …
Date: December 16, 2002
Creator: Becker, R; Belak, J & Campbell, G
Object Type: Report
System: The UNT Digital Library
Discriminatory Pricing and the Robinson-Patman Act: Brief Overview, Including Some Exceptions (open access)

Discriminatory Pricing and the Robinson-Patman Act: Brief Overview, Including Some Exceptions

None
Date: October 16, 2002
Creator: Rubin, Janice E.
Object Type: Report
System: The UNT Digital Library
An Updated Point Design for Heavy Ion Fusion (open access)

An Updated Point Design for Heavy Ion Fusion

An updated, self-consistent point design for a heavy ion fusion (HIF) power plant based on an induction linac driver, indirect-drive targets, and a thick liquid wall chamber has been completed. Conservative parameters were selected to allow each design area to meet its functional requirements in a robust manner, and thus this design is referred to as the Robust Point Design (RPD-2002). This paper provides a top-level summary of the major characteristics and design parameters for the target, driver, final focus magnet layout and shielding, chamber, beam propagation to the target, and overall power plant.
Date: December 16, 2002
Creator: Yu, S. S.; Meier, W. R.; Abbott, R. B.; Barnard, J. J.; Brown, T.; Callahan, D. A. et al.
Object Type: Article
System: The UNT Digital Library
RF Phase Stability and Electron Beam Characterization for the PLEIADES Thomson X-Ray Source (open access)

RF Phase Stability and Electron Beam Characterization for the PLEIADES Thomson X-Ray Source

We report on the performance of an S-band RF photocathode electron gun and accelerator for operation with the PLEIADES Thomson x-ray source at LLNL. To produce picosecond, high brightness x-ray pulses, picosecond timing, terahertz bandwidth diagnostics, and RF phase control are required. Planned optical, RF, x-ray and electron beam measurements to characterize the dependence of electron beam parameters and synchronization on RF phase stability are presented.
Date: October 16, 2002
Creator: Brown, W J; Hartemann, F V; Tremaine, A M; Springer, P T; Le Sage, G P; Barty, C P J et al.
Object Type: Article
System: The UNT Digital Library
“Agricultural Commodity,” “Agricultural Product,” “Farm Product” and Related Terms: Definitions for Federal Policy (open access)

“Agricultural Commodity,” “Agricultural Product,” “Farm Product” and Related Terms: Definitions for Federal Policy

This report defines a number of terms within the realm of agricultural production.
Date: December 16, 2002
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Congressional Gold Medals 1776-2002 (open access)

Congressional Gold Medals 1776-2002

This report responds to congressional inquiries concerning this process, and includes a historical examination and chronological list of these awards.
Date: April 16, 2002
Creator: Stathis, Stephen W.
Object Type: Report
System: The UNT Digital Library
Laminar Validation Cases for the Incompressible Flow Model in ALE3D (open access)

Laminar Validation Cases for the Incompressible Flow Model in ALE3D

To benchmark the incompressible flow model in ALE3D, two test cases are conducted. The first case of two-dimensional flow over a flat plate is selected because it provides a straightforward example to determine whether or not ALE3D can grow a boundary layer by viscous diffusion. The benefit of the flat plate problem is that under certain conditions, the governing Navier-Stokes equations can be simplified and solved with numerical techniques, providing an independent result that can be compared with the solution from ALE3D. The second test case is that of two-dimensional, laminar flow about a circular cylinder. This test case is selected because it provides the complexity of an unsteady bluff-body wake in which vorticity is periodically shed from the surface of the cylinder. Since this canonical flow problem has been studied extensively both experimentally and computationally, the results from ALE3D can be compared with those presented in the literature. The results for the flat plate case demonstrate that the implicit time integration scheme results in an approximate twenty-four-fold reduction of the simulation time over that of the explicit time integration scheme. On the other hand, a problematic trend is observed in the explicit time integration scheme used in the flat …
Date: July 16, 2002
Creator: Ortega, J
Object Type: Report
System: The UNT Digital Library
Modeling and Characterization of Recompressed Damaged Materials (open access)

Modeling and Characterization of Recompressed Damaged Materials

Ductile metals subjected to shock loading can develop internal damage through nucleation growth and coalescence of voids. The extent of damage can range from a well-defined spall plane induced by light shocks to more widespread damage caused by strong shocks. Because damage materials are often part of a dynamic system, significant additional deformation can occur in extensively damaged materials. To represent material behavior in simulation codes for stockpile stewardship calculations, both the damage and the recompression processes must be modeled accurately. Currently, no experimentally based models of recompression behavior are available for use in numerical simulations. The goals of this project are to (1) perform recompression experiments on samples containing controlled and well-characterized damage, (2) develop a model capturing the recompression behavior and residual strength based on the experimental data and micro-mechanical models, and (3) implement the model in an Advanced Simulation and Computing (ASCI) code (ALE3D). The recompression model, together with failure models based on underlying physical mechanisms, will provide a more accurate representation of material behavior-information that is needed for simulations of explosively loaded materials such as those required by the Stockpile Stewardship Program.
Date: December 16, 2002
Creator: Becker, R; Belak, J & Campbell, G
Object Type: Report
System: The UNT Digital Library
Arms Control and Strategic Nuclear Weapons: Unilateral vs. Bilateral Reductions (open access)

Arms Control and Strategic Nuclear Weapons: Unilateral vs. Bilateral Reductions

This report contains the unilateral and bilateral reductions on the arms control and strategic nuclear weapons.
Date: May 16, 2002
Creator: Woolf, Amy F.
Object Type: Report
System: The UNT Digital Library
Campaign Finance: Constitutional and Legal Issues of Soft Money (open access)

Campaign Finance: Constitutional and Legal Issues of Soft Money

This report discusses the political party soft money, corporate and labor union soft money and 107th congress legislative activity.
Date: April 16, 2002
Creator: Whitaker, L. Paige
Object Type: Report
System: The UNT Digital Library
Latino Political Participation and Representation in Elective Office (open access)

Latino Political Participation and Representation in Elective Office

None
Date: July 16, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Authorization of Use of U.S. Armed Forces Against Iraq: Side-by-Side Comparison of Selected Legislative Proposals (open access)

Authorization of Use of U.S. Armed Forces Against Iraq: Side-by-Side Comparison of Selected Legislative Proposals

This report presents a side-by-side comparison of Public Law 107-243 and selected alternative legislative proposals considered in 107th Congress related to Authorization of Use of U.S. Armed Forces Against Iraq.
Date: October 16, 2002
Creator: Rennack, Dianne E.
Object Type: Report
System: The UNT Digital Library
Protection of National Security Information: The Classified Information Protection Act of 2001 (open access)

Protection of National Security Information: The Classified Information Protection Act of 2001

None
Date: January 16, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Recent Advances in the Collapse and Fragmentation of Turbulent Molecular Cloud Cores (open access)

Recent Advances in the Collapse and Fragmentation of Turbulent Molecular Cloud Cores

The formation of Giant Molecular Clouds (GMCs) sets the stage for the formation of protostellar systems by the gravitational collapse of dense regions within the GMC that fragment into smaller core components that in turn condense into stars. Developing a comprehensive theory of star formation remains one of the most elusive, and most important, goals of theoretical astrophysics. Inherent in the difficulty in attaining this goal is that the gravitational collapse depends critically upon initial conditions within the cores which only recently have been known with sufficient accuracy to permit a realistic theoretical attack on the problem. Observations of stars in the vicinity of the Sun show that binary systems are prevalent and appear to be a general outcome of the collapse and fragmentation process. Despite years of progress, theoretical studies have still not determined why binary stars occur with such frequency, or indeed, even what processes determine the transition from single stars to binaries and thence to multiple stellar systems. One of the major goals of this research is to understand the nature of the formation of binary and multiple stellar systems with typical low mass stars 0.2 to 3 M{sub {circle_dot}} and the physical properties of these systems. …
Date: December 16, 2002
Creator: Klein, R L; Fisher, R; Krumholz, M & McKee, C F
Object Type: Article
System: The UNT Digital Library
China/Taiwan: Evolution of the “One China” Policy – Key Statements from Washington, Beijing, and Taipei (open access)

China/Taiwan: Evolution of the “One China” Policy – Key Statements from Washington, Beijing, and Taipei

This report provides information about the Evolution of the “One China” Policy and Key Statements from Washington, Beijing, and Taipei. Policy on "one China " covers three major aspects like sovereignty, cross-strait dialogue, PRC use of force.
Date: December 16, 2002
Creator: Kan, Shirley A.
Object Type: Report
System: The UNT Digital Library
Glow Discharge Mass Spectrometry Analysis of LX-17 and PBX-9502 High Explosive Samples (open access)

Glow Discharge Mass Spectrometry Analysis of LX-17 and PBX-9502 High Explosive Samples

As part of the Campaign 4 effort in A Division we have done an analysis of several high explosives that are used in the current nuclear stockpile. In particular we have looked at samples of LX-17 and PBX-9502. The analysis was done using the glow discharge mass spectrometer that is currently located in B132N and operated by Mark Lane of the Chemistry and Material Science (CMS) Directorate. George Overturf from CMS obtained small samples of high explosive for the measurements. From the analysis we wanted to verify the actual atomic composition of the high explosive, see how that compared with the nominal composition, and understand whether any significant impurities existed in the samples. We present the analysis of several LX-17 and PBX-9502 samples using the glow discharge mass spectrometer to measure both the main constituents of the high explosive as well as any trace materials that may be present.
Date: December 16, 2002
Creator: Nilsen, J; Castor, J I; Lane, M A & Overturf, G E
Object Type: Report
System: The UNT Digital Library
Iran: Current Developments and U.S. Policy (open access)

Iran: Current Developments and U.S. Policy

This report includes information regarding Iranian current developments and U.S. policy. Iran's strategic buildup, Iranian foreign policy and terrorism involvement, and human rights concerns are among topics discussed in this report.
Date: October 16, 2002
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Opportunities for Catalysis in The 21st Century. A report from the Basic Energy Sciences Advisory Committee (open access)

Opportunities for Catalysis in The 21st Century. A report from the Basic Energy Sciences Advisory Committee

Chemical catalysis affects our lives in myriad ways. Catalysis provides a means of changing the rates at which chemical bonds are formed and broken and of controlling the yields of chemical reactions to increase the amounts of desirable products from these reactions and reduce the amounts of undesirable ones. Thus, it lies at the heart of our quality of life: The reduced emissions of modern cars, the abundance of fresh food at our stores, and the new pharmaceuticals that improve our health are made possible by chemical reactions controlled by catalysts. Catalysis is also essential to a healthy economy: The petroleum, chemical, and pharmaceutical industries, contributors of $500 billion to the gross national product of the United States, rely on catalysts to produce everything from fuels to ''wonder drugs'' to paints to cosmetics. Today, our Nation faces a variety of challenges in creating alternative fuels, reducing harmful by-products in manufacturing, cleaning up the environment and preventing future pollution, dealing with the causes of global warming, protecting citizens from the release of toxic substances and infectious agents, and creating safe pharmaceuticals. Catalysts are needed to meet these challenges, but their complexity and diversity demand a revolution in the way catalysts are …
Date: May 16, 2002
Creator: White, J. M. & Bercaw, J.
Object Type: Report
System: The UNT Digital Library
Groundwater plume control with phytotechnologies at Argonne National Laboratory. (open access)

Groundwater plume control with phytotechnologies at Argonne National Laboratory.

In 1999, Argonne National Laboratory-East (ANL-E) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume. This goal was to be accomplished by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual VOCs, and removing tritium from the subsoil and groundwater. The U.S. EPA Superfund Innovative Technology Evaluation Program (SITE) and ANL-E evaluated the demonstration. The effectiveness of the various plantings was monitored directly through groundwater measurements and samples, and indirectly via soil moisture probes, plant tissue analysis, microbial studies, geochemical analysis, and sap flow monitoring. A weather station with data logging equipment was installed. ANL-E modeled the predicted effect of the plants on the groundwater using MODFLOW. The demonstration has lasted three growing seasons and continues. This paper presents the results of the sampling, monitoring, and modeling efforts to date. The project was not …
Date: July 16, 2002
Creator: Rock, Steve; Negri, M. Cristina; Quinn, John; Wozniak, James & McPherson, Jorge
Object Type: Article
System: The UNT Digital Library
Advanced visualization technology for terascale particle accelerator simulations (open access)

Advanced visualization technology for terascale particle accelerator simulations

This paper presents two new hardware-assisted rendering techniques developed for interactive visualization of the terascale data generated from numerical modeling of next generation accelerator designs. The first technique, based on a hybrid rendering approach, makes possible interactive exploration of large-scale particle data from particle beam dynamics modeling. The second technique, based on a compact texture-enhanced representation, exploits the advanced features of commodity graphics cards to achieve perceptually effective visualization of the very dense and complex electromagnetic fields produced from the modeling of reflection and transmission properties of open structures in an accelerator design. Because of the collaborative nature of the overall accelerator modeling project, the visualization technology developed is for both desktop and remote visualization settings. We have tested the techniques using both time varying particle data sets containing up to one billion particle s per time step and electromagnetic field data sets with millions of mesh elements.
Date: November 16, 2002
Creator: Ma, K-L; Schussman, G.; Wilson, B.; Ko, K.; Qiang, J. & Ryne, R.
Object Type: Article
System: The UNT Digital Library
Polarization of prompt J/{psi} and {Upsilon}(nS). (open access)

Polarization of prompt J/{psi} and {Upsilon}(nS).

We review predictions, based on the nonrelativistic QCD factorization framework, for the polarizations of prompt J={psi}'s and {Upsilon}(nS)'s produced at the Fermilab Tevatron. We also discuss the effect of relativistic corrections on the theoretical prediction for the polarization of prompt J={psi}'s at the Tevatron.
Date: July 16, 2002
Creator: Lee, J.
Object Type: Article
System: The UNT Digital Library