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Residual Stress Testing of Outer 3013 Containers

Description: A Gas Tungsten Arc Welded (GTAW) outer 3013 container and a laser welded outer 3013 container have been tested for residual stresses according to the American Society for Testing Materials (ASTM) Standard G-36-94 [1]. This ASTM standard describes a procedure for conducting stress-corrosion cracking tests in boiling magnesium chloride (MgCl2) solution. Container sections in both the as-fabricated condition as well as the closure welded condition were evaluated. Significantly large residual stresses were observed in the bottom half of the as-fabricated container, a result of the base to can fabrication weld because through wall cracks were observed perpendicular to the weld. This observation indicates that regardless of the closure weld technique, sufficient residual stresses exist in the as-fabricated container to provide the stress necessary for stress corrosion cracking of the container, at the base fabrication weld. Additionally, sufficiently high residual stresses were observed in both the lid and the body of the GTAW as well as the laser closure welded containers. The stresses are oriented perpendicular to the closure weld in both the container lid and the container body. Although the boiling MgCl2 test is not a quantitative test, a comparison of the test results from the closure welds shows that there are noticeably more through wall cracks in the laser closure welded container than in the GTAW closure welded container.
Date: February 12, 2004
Creator: Dunn, K.
Partner: UNT Libraries Government Documents Department

Particle-in-cell Simulations with Kinetic Electrons

Description: A new scheme, based on an exact separation between adiabatic and nonadiabatic electron responses, for particle-in-cell (PIC) simulations of drift-type modes is presented. The (linear and nonlinear) elliptic equations for the scalar fields are solved using a multi-grid solver. The new scheme yields linear growth rates in excellent agreement with theory and it is shown to conserve energy well into the nonlinear regime. It is also demonstrated that simulations with few electrons are reliable and accurate, suggesting that large-scale, PIC simulations with electron dynamics in toroidal geometry (e.g., tokamaks and stellarators plasmas) are within reach of present-day massively parallel supercomputers.
Date: February 12, 2004
Creator: Lewandowski, J.L.V.
Partner: UNT Libraries Government Documents Department

Optimizing receiver configurations for resolution of equivalent dipole polarizabilities in situ

Description: Equivalent dipole polarizabilities are a succinct way to summarize the inductive response of an isolated conductive body at distances greater than the scale of the body. At any time lag or frequency, an equivalent dipole polarizability response is comprised of 9 parameters; six specifying an equivalent dipole polarizability matrix (which is symmetric) and three specifying the apparent location of the body center. Smith and Morrison (2002) give equations for calculating uncertainties in equivalent dipole polarizability and position based on analysis of an iterative linearized inversion. Here, the root mean squared uncertainty in polarizability is weighted and summed over a number of control points and minimized using an evolutionary algorithm for a number of instrument designs. Three families of designs are presented: single transmitter systems for use on a 2-D grid of positions with negligible error in relative instrument location, two transmitter systems for use on a line of positions with negligible error in relative instrument location, and three transmitter systems for stand alone use. Results for the one and two transmitter systems are strongly degraded by errors in instrument position, whereas the three transmitter systems are insensitive to instrument positioning errors.
Date: February 12, 2004
Creator: Smith, J. Torquil & Morrison, H. Frank
Partner: UNT Libraries Government Documents Department

Compositing and Characterization of Samples from Hanford Tank 241-AY-102/ C-106

Description: As part of the program to provide waste characterization and pretreatment data to support the Waste Treatment Plant WTP mission to treat Hanford tank waste, an approximate 3.8L sample of waste from Hanford Tank 241-AY-102/C-106 was received at the Savannah River Technology Center (SRTC). The waste sample was characterized to provide feed for pretreatment testing. The characterization data provides a basis for rational development of pretreatment processes, determination of reagent requirements, and development of physical design parameters for the pretreatment plant.
Date: February 12, 2004
Creator: Coleman, C. J.
Partner: UNT Libraries Government Documents Department

Financial Management: Some DOD Contractors Abuse the Federal Tax System with Little Consequence

Description: A letter report issued by the General Accounting Office with an abstract that begins "GAO was asked to determine (1) the magnitude of unpaid federal taxes owed by Department of Defense (DOD) contractors, (2) whether indications exist of abuse or criminal activity by DOD contractors related to the federal tax system, (3) whether DOD and the Internal Revenue Service (IRS) have effective processes and controls in place to use the Treasury Offset Program (TOP) in collecting unpaid federal taxes from DOD contractors, and (4) whether DOD contractors with unpaid federal taxes are prohibited by law from receiving contracts from the federal government."
Date: February 12, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Business Systems Modernization: Internal Revenue Service Needs to Further Strengthen Program Management

Description: Testimony issued by the General Accounting Office with an abstract that begins "The Internal Revenue Service (IRS) has been grappling with modernizing its computer systems for many years. IRS's current program, commonly referred to as Business Systems Modernization (BSM), began in fiscal year 1999; about $1.4 billion has been reported spent on it to date. While progress has been made, the program continues to face significant challenges and risks. In recognition of these risks, IRS and a contractor recently completed several comprehensive assessments of BSM, including one of its Customer Account Data Engine (CADE) project, which is to modernize the agency's outdated data management system. At the request of the Subcommittee on Oversight, House Committee on Ways and Means, GAO's testimony will summarize (1) GAO's prior findings and recommendations, along with those of the recent assessments; and (2) actions IRS has taken or plans to take to address these issues."
Date: February 12, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Financial Management: Some DOD Contractors Abuse the Federal Tax System with Little Consequence

Description: Testimony issued by the General Accounting Office with an abstract that begins "GAO addressed issues related to three high-risk areas including the Department of Defense (DOD) and the Internal Revenue Service (IRS) financial management and IRS collection of unpaid taxes. This testimony provides a perspective on (1) the magnitude of unpaid federal taxes owed by DOD contractors, (2) whether indications exist of abuse or criminal activity by DOD contractors related to the federal tax system, (3) whether DOD and IRS have effective processes and controls in place to use the Treasury Offset Program (TOP) in collecting unpaid federal taxes from DOD contractors, and (4) whether DOD contractors with unpaid taxes are prohibited by law from receiving federal contracts. In a companion report issued today."
Date: February 12, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Public Health Preparedness: Response Capacity Improving, but Much Remains to Be Accomplished

Description: Testimony issued by the General Accounting Office with an abstract that begins "The anthrax incidents in the fall of 2001 and the severe acute respiratory syndrome (SARS) outbreak in 2002-2003 have raised concerns about the nation's ability to respond to a major public health threat, whether naturally occurring or the result of bioterrorism. The anthrax incidents strained the public health system, including laboratory and workforce capacities, at the state and local levels. The SARS outbreak highlighted the challenges of responding to new and emerging infectious disease. The current influenza season has heightened concerns about the nation's ability to handle a pandemic. GAO was asked to examine improvements in state and local preparedness for responding to major public health threats and federal and state efforts to prepare for an influenza pandemic. This testimony is based on GAO's recent report, HHS Bioterrorism Preparedness Programs: States Reported Progress but Fell Short of Program Goals for 2002, GAO-04- 360R (Feb. 10, 2004). This testimony also updates information contained in GAO's report on federal and state planning for an influenza pandemic, Influenza Pandemic: Plan Needed for Federal and State Response, GAO- 01-4 (Oct. 27, 2000)."
Date: February 12, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Aviation Security: Challenges Exist in Stabilizing and Enhancing Passenger and Baggage Screening Operations

Description: Testimony issued by the General Accounting Office with an abstract that begins "Securing commercial aviation is a daunting task--with hundreds of airports and thousands of flights daily carrying millions of passengers and pieces of baggage. In an effort to strengthen the security of commercial aviation, the Transportation Security Administration (TSA) was created and charged with making numerous enhancements to aviation security, including federalizing passenger and baggage screening and screening checked baggage using explosive detection systems. To assess the progress of passenger and baggage screening operations, GAO was asked to describe TSA's efforts to (1) hire and deploy passenger and baggage screeners, (2) train the screening workforce, (3) measure screener performance in detecting threat objects, and (4) leverage and deploy screening equipment and technologies."
Date: February 12, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

High-Accuracy X-ray Imaging of Meso-scale Targets -- Final Report

Description: Hundreds of target assemblies will be constructed annually for use on NIF or OMEGA in the near future. Currently, we do not have the capability to tomographically characterize the target assemblies at the desired resolution. Hence, we cannot verify if an assembly has been assembled correctly. The Engineering Directorate, through the LDRD program, provided funding to help solve this problem. This report describes the work accomplished by this LDRD ER (tracking number: 01-ERD-093). The main focus of the LDRD was on the research and development of an x-ray imaging instrument. The instrument design was based on a Woelter [1] Type-I design. The LDRD-ER began as a mid-year project in April 2001. After 2.5 years the LDRD-ER was combined with other work to create a new LDRD-SI. The LDRD-SI was terminated in December 2003. The x-ray microscope research and development was never completed. This report describes the work that was accomplished. It includes discussions on the instrument concept, the optical design, mandrel fabrication, instrument fabrication, optic fabrication, and optic testing.
Date: February 12, 2004
Creator: Nederbragt, W W
Partner: UNT Libraries Government Documents Department

A Microbeam Bending Method for Studying Stress-Strain Relations for Metal Thin Films on Silicon Substrates

Description: We have developed a microbeam bending technique for determining elastic-plastic, stress-strain relations for thin metal films on silicon substrates. The method is similar to previous microbeam bending techniques, except that triangular silicon microbeams are used in place of rectangular beams. The triangular beam has the advantage that the entire film on the top surface of the beam is subjected to a uniform state of plane strain as the beam is deflected, unlike the standard rectangular geometry where the bending is concentrated at the support. We present a method of analysis for determining two Ramberg-Osgood parameters for describing the stress-strain relation for the film. These parameters are obtained by fitting the elastic-plastic model to the measured load-displacement data, and utilizing the known elastic properties of both film and substrate. As a part of the analysis we compute the position of the neutral plane for bending, which changes as the film deforms plastically. This knowledge, in turn, allows average stress-strain relations to be determined accurately without forcing the film to closely follow the Ramberg-Osgood law. The method we have developed can be used to determine the elastic-plastic properties of thin metal films on silicon substrates up to strains of about 1%. Utilizing this technique, both yielding and strain hardening of Cu thin films on silicon substrates have been investigated. Copper films with dual crystallographic textures and different grain sizes, as well as others with strong <111> textures have been studied. Three strongly textured <111> films were studied to examine the effect of film thickness on the deformation properties of the film. These films show very high rates of work hardening, and an increase in the yield stress and work hardening rate with decreasing film thickness, consistent with current dislocation models.
Date: February 12, 2004
Creator: Florando, J N & Nix, W D
Partner: UNT Libraries Government Documents Department

Secure Communications in High Speed Fiber Optical Networks Using Code Division Multiple Access (CDMA) Transmission

Description: This project is focused on the development of advanced components and system technologies for secure data transmission on high-speed fiber optic data systems. This work capitalizes on (1) a strong relationship with outstanding faculty at the University of California-Davis who are experts in high speed fiber-optic networks, (2) the realization that code division multiple access (CDMA) is emerging as a bandwidth enhancing technique for fiber optic networks, (3) the realization that CDMA of sufficient complexity forms the basis for almost unbreakable one-time key transmissions, (4) our concepts for superior components for implementing CDMA, (5) our expertise in semiconductor device processing and (6) our Center for Nano and Microtechnology, which is where the majority of the experimental work was done. Here we present a novel device concept, which will push the limits of current technology, and will simultaneously solve system implementation issues by investigating new state-of-the-art fiber technologies. This will enable the development of secure communication systems for the transmission and reception of messages on deployed commercial fiber optic networks, through the CDMA phase encoding of broad bandwidth pulses. CDMA technology has been developed as a multiplexing technology, much like wavelength division multiplexing (WDM) or time division multiplexing (TDM), to increase the potential number of users on a given communication link. A novel application of the techniques created for CDMA is to generate secure communication through physical layer encoding. Physical layer encoding devices are developed which utilize semiconductor waveguides with fast carrier response times to phase encode spectral components of a secure signal. Current commercial technology, most commonly a spatial light modulator, allows phase codes to be changed at rates of only 10's of Hertz ({approx}25ms response). The use of fast (picosecond to nanosecond) carrier dynamics of semiconductors, as opposed to field dynamics of liquid crystal molecules, enable phase codes at ...
Date: February 12, 2004
Creator: Han, I; Bond, S; Welty, R; Du, Y; Yoo, S; Reinhardt, C et al.
Partner: UNT Libraries Government Documents Department

Toward volatile metal complexes of rutherfordium - results of testexeriments with Zr and Hf

Description: The chemical investigation of the transactinide elements (TAN, Z {ge}104) is a topic of great interest in recent nuclear chemistry research. The highly charged nucleus accelerates the innermost electrons to relativistic velocities thus causing contraction of spherical (s, p{sub 1/2}) orbitals and expansion of the others (p{sub 3/2}, d, and f), which directly affects the chemical behavior of these elements. Deviations from trends established in the periodic table may therefore occur due to these so-called relativistic effects [1,2]. In gas phase experiments, mostly volatile inorganic compounds (e.g., halides or oxides) of TAN were investigated. We refer to [3] for a recent review. For reasons such as low production cross-sections or short half-lives, but also technical challenges, more sophisticated chemical studies have not yet been possible. One restriction in present TAN research is the plasma behind the target caused by the intense heavy ion beam. ''Weak'' molecules (e.g., organic ligands) are immediately destroyed, thus limiting the possibilities of synthesizing chemical compounds directly behind the target to ''simple'' and robust inorganic compounds. It is highly desirable to expand the knowledge on the chemical behavior of the TAN to other compound classes, e.g., volatile metal complexes. The use of the Berkeley Gas-filled Separator (BGS) [4] as a physical preseparator makes such studies possible by separating the beam from the desired TAN isotopes.
Date: February 12, 2004
Creator: Dullmann, Ch.E.; Pang, G.K.; Folden III, C.M.; Gregorich, K.E.; Hoffman, D.C.; Nitsche, H. et al.
Partner: UNT Libraries Government Documents Department