36 Matching Results

Search Results

Simulation of DIII-D Flat q Discharges

Description: The Advanced Tokamak plasma configuration has significant potential for the economical production of fusion power. Research on various tokamak experiments are pursuing these plasmas to establish high {beta}, high bootstrap current fraction, 100% noninductive current, and good energy confinement, in a quasi-stationary state. One candidate is the flat q discharge produced in DIII-D, where the safety factor varies from 2.0 on axis, to slightly below 2.0 at the minimum, and then rises to about 3.5 at the 95% surface. This plasma is prototypical of those studied for power plants in the ARIES tokamak studies. The plasma is produced by ramping up the plasma current and ramping down the toroidal field throughout the discharge. The plasma current reaches 1.65 MA, and the toroidal field goes from 2.25 to 1.6 T. The q{sub min} remains high and at large radius, {rho} {approx} 0.6. The plasma establishes an internal transport barrier in the ion channel, and transitions to H-mode. The free-boundary Tokamak Simulation Code (TSC) is being used to model the discharge and project the impact of changes in the plasma current, toroidal field, and injected power programming.
Date: June 25, 2004
Creator: Kessel, C.E.; Garofalo, A. & Terpstra, T.
Partner: UNT Libraries Government Documents Department

Homeland Security: Communication Protocols and Risk Communication Principles Can Assist in Refining the Advisory System

Description: A letter report issued by the General Accounting Office with an abstract that begins "Established in March 2002, the Homeland Security Advisory System was designed to disseminate information on the risk of terrorist acts to federal agencies, states, localities, and the public. However, these entities have raised questions about the threat information they receive from the Department of Homeland Security (DHS) and the costs they incurred as a result of responding to heightened alerts. This report examines (1) the decision making process for changing the advisory system national threat level; (2) information sharing with federal agencies, states, and localities, including the applicability of risk communication principles; (3) protective measures federal agencies, states, and localities implemented during high (codeorange) alert periods; (4) costs federal agencies reported for those periods; and (5) state and local cost information collected by DHS."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Student Mentoring Programs: Education's Monitoring and Information Sharing Could Be Improved

Description: A letter report issued by the General Accounting Office with an abstract that begins "As part of the No Child Left Behind Act (NCLBA) of 2001, the Congress authorized a 3-year, $17 million per year school-based mentoring grant program. For fiscal year 2004, Congress has increased funding to about $50 million to fund additional mentoring efforts. Congress requested that GAO provide information on the student mentoring program. To do this, GAO answered the following questions: (1) What are the basic elements, policies, and procedures of successful mentoring programs? (2) What are the key characteristics of NCLBA-funded mentoring efforts, including the extent to which they have the basic elements, policies, and procedures of successful mentoring programs? (3) How does the Department of Education monitor program implementation? (4) What are Education's and grantees' plans to assess program outcomes?"
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

National Nuclear Security Administration: Key Management Structure and Workforce Planning Issues Remain As NNSA Conducts Downsizing

Description: A letter report issued by the General Accounting Office with an abstract that begins "The National Nuclear Security Administration (NNSA), a separately organized agency within the Department of Energy (DOE), is responsible for the management and security of the nation's nuclear weapons, nonproliferation, and naval reactor programs. NNSA oversees contractors that operate its facilities to ensure that activities are effective and in line with departmental policy. In December 2002, NNSA began implementing a major reorganization aimed at solving important long-standing organizational issues. GAO reviewed NNSA's overall reorganization efforts to assess (1) the extent to which it is addressing in practice the past problems concerning the unclear delineation of authority and responsibility, (2) workforce planning, and (3) its impact on federal oversight of contractor activities."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Medicare Dialysis Facilities: Beneficiary Access Stable and Problems in Payment System Being Addressed

Description: A letter report issued by the General Accounting Office with an abstract that begins "Medicare covers about 90 percent of patients with end-stage renal disease (ESRD), the permanent loss of kidney function. Most ESRD patients receive regular hemodialysis treatments, a process that removes toxins from the blood, at a dialysis facility. A small percentage dialyzes-at home. From 1991 through 2001, the ESRD patient population more than doubled, from about 201,000 to 406,000. As the need for services grows, so do concerns about beneficiary access to and Medicare payment for dialysis services. The Medicare, Medicaid, and SCHIP Benefits Improvement and Protection Act of 2000 directed GAO to study beneficiaries' access to dialysis services. In this report, GAO (1) assessed the supply of dialysis facilities and the services they provide, overall and relative to beneficiary residence, and (2) assessed the extent to which Medicare payments for dialysis services are adequate and the methodology is appropriate. In order to assess the supply of dialysis facilities, GAO used Facility Surveys collected by the Centers for Medicare & Medicaid Services (CMS) and outpatient claims, the bills submitted to Medicare by providers of certain outpatient services from 1998 through 2001. To assess the adequacy of Medicare payment and the appropriateness of the payment methodology, GAO used 2001 Medicare cost reports and outpatient claims submitted by freestanding dialysis facilities."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Foreign Military Sales: Improved Navy Controls Could Prevent Unauthorized Shipments of Classified and Controlled Spare Parts to Foreign Countries

Description: A letter report issued by the General Accounting Office with an abstract that begins "From 1993 through 2002, the Department of Defense (DOD) delivered over $150 billion in services and defense articles, including classified and controlled items, to foreign countries through foreign military sales programs administered by the military. Foreign countries may request items using blanket orders, which are for a specific dollar value and are used to simplify supply actions on certain types of items. GAO was asked to review whether the Navy's key internal controls restricted blanket orders for (1) classified spare parts and (2) controlled items sold to foreign countries. Also, GAO was asked to determine if periodic tests were conducted to ensure that the Navy's system is working as intended."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Federal Budget: Agency Obligations by Budget Function and Object Classification for Fiscal Year 2003

Description: A letter report issued by the General Accounting Office with an abstract that begins "Members of the Congress and governmental experts have expressed repeated interest in examining the overlapping and fragmented functions and activities of the federal government. As a first-level look at potential overlap and fragmentation, the Chairwoman, Subcommittee on Civil Service and Agency Organization, House Committee on Government Reform, asked GAO to present information on which federal agencies spend funds in which federal mission areas. This report examines federal spending through two commonly used analytical approaches--budget functions and object classifications."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Mass Transit: FTA Needs to Better Define and Assess Impact of Certain Policies on New Starts Program

Description: A letter report issued by the General Accounting Office with an abstract that begins "The Transportation Equity Act for the 21st Century (TEA-21) and subsequent legislation authorized about $8.3 billion in guaranteed funding for the Federal Transit Administration's (FTA) New Starts program, which funds fixed guideway transit projects, such as rail and trolley projects, through FFGAs. GAO assessed the New Starts process for the fiscal year 2005 cycle. GAO identified (1) the number of projects that were evaluated, rated, and proposed for new FFGAs and how recent changes to the process were reflected in ratings; (2) the proposed funding commitments in the administration's budget request and legislative reauthorization proposals; and (3) the extent to which amounts appropriated since 1998 fulfilled FFGAs."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Human Capital: Selected Agencies' Use of Alternative Service Delivery Options for Human Capital Activities

Description: A letter report issued by the General Accounting Office with an abstract that begins "Human capital offices have traditionally used alternative service delivery (ASD)--the use of other than internal staff to provide a service or to deliver a product--as a way to reduce costs for transaction-based services. GAO was asked to identify which human capital activities agencies were selecting for ASD, the reasons why, how they were managing the process, and some of the lessons they had learned. Eight agencies were selected to provide illustrative examples of ASD use."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Military Personnel: DOD Has Not Implemented the High Deployment Allowance That Could Compensate Servicemembers Deployed Frequently for Short Periods

Description: A letter report issued by the General Accounting Office with an abstract that begins "The fiscal year 2004 National Defense Authorization Act directed GAO to assess the special pays and allowances for servicemembers who are frequently deployed for less than 30 days, and to specifically review the family separation allowance. GAO's objectives were to assess (1) the rationale for the family separation allowance eligibility requirements, including the required duration of more than 30 consecutive days away from a member's duty station; (2) the extent to which DOD has identified short-term deployments as a family separation allowance issue; and (3) what special pays and allowances, in addition to basic military compensation, are available to compensate members deployed for less than 30 days."
Date: June 25, 2004
Creator: United States. General Accounting Office.
Partner: UNT Libraries Government Documents Department

Tobacco Price Support: An Overview of the Program

Description: About 94 percent of U.S. tobacco production is flue-cured and burley (cigarette tobacco types). These crops are particularly important to the agriculture of North Carolina and Kentucky. The federal tobacco price support program is designed to support and stabilize prices for farmers.
Date: June 25, 2004
Creator: Womach, Jasper
Partner: UNT Libraries Government Documents Department

A Scalable Implementation of a Finite-Volume Dynamical Core in the Community Atmosphere Model

Description: A distributed memory message-passing parallel implementation of a finite-volume discretization of the primitive equations in the Community Atmosphere Model is presented. Due to the data dependencies resulting from the polar singularity of the latitude-longitude coordinate system, it is necessary to employ two separate domain decompositions within the dynamical core. Data must be periodically redistributed between these two decompositions. In addition, the domains contain halo regions that cover the nearest neighbor data dependencies. A combination of several techniques, such as one-sided communication and multithreading, are presented to optimize data movements. The resulting algorithm is shown to scale to very large machine configurations, even for relatively coarse resolutions.
Date: June 25, 2004
Creator: Sawyer, W & Mirin, A
Partner: UNT Libraries Government Documents Department

Experiments on the Scaling of Ionization Balance vs. Electron and Radiation Temperature in Non-LTE Gold Plasmas

Description: Understanding and predicting the behavior of high-Z non-LTE plasmas is important for developing indirect-drive inertial confinement fusion. Extending earlier work from the Nova laser, we present results from experiments using the Omega laser to study the ionization balance of gold as a function of electron and radiation temperature. In these experiments, gold samples embedded in Be disks expand under direct laser heating to n{sub e} {approx} 10{sup 21} cm{sup -3}, with T{sub e} varying from 0.8 to 2.5 keV. An additional finite radiation field with effective temperature T{sub r} up to 150 eV is provided by placing the gold-Be disks inside truncated 1.2 mm diameter tungsten-coated cylindrical hohlraums with full laser entrance holes. Densities are measured by imaging of plasma expansion. Electron temperatures are diagnosed with either 2 {omega} or 4 {omega} Thomson scattering, and also K-shell spectroscopy of KCl tracers co-mixed with the gold. Hohlraum flux and effective radiation temperature are measured using an absolutely-calibrated multichannel filtered diode array. Spectroscopic measurements of the M-shell gold emission in the 2.9-4 keV spectral range provide ionization balance and charge state distribution information. The spectra show strong variation with T{sub e}, strong variation with the applied T{sub r} at T{sub e} below 1.6 keV, and relatively little variation with T{sub r} at higher T{sub e} (upwards of 2 keV). We summarize our most recent spectral analyses and discuss emerging and outstanding issues.
Date: June 25, 2004
Creator: Heeter, R F; Hansen, S B; Beiersdorfer, P; Foord, M E; Fournier, K B; Froula, D H et al.
Partner: UNT Libraries Government Documents Department

Observation and Measurement of MHD Activity Using Motional Stark Effect (MSE) Diagnostic

Description: In a new mode of measurement, the amplitude of a tearing mode rotating at frequencies of up to tens of KHz has been obtained using the spectral features of high frequency MSE data. A formulation has been developed to calculate the pitch angle oscillations associated with these instabilities, from the MSE spectrum. Density fluctuations can be simultaneously obtained from MSE measurements if the intensity response to density variation can be calibrated. Examples of observations are given and detection limits are explored.
Date: June 25, 2004
Creator: Jayakumar, R; Makowski, M; Allen, S; Moller, J & Rhodes, T
Partner: UNT Libraries Government Documents Department

Melting of aluminum, molybdenum and the light actinides

Description: A semi-empirical model was used to explain why the measured melting curves of molybdenum, and the other bcc transition metals, have an unusually low slope (dT/dP{approx}0). The total binding energy of Mo is written as the sum of the repulsive energy of the ions and sp-electrons (modeled by an inverse 6th power potential) and the d-band cohesive energy described by the well known Friedel equation. Using literature values for the Mo band width energy, the number of d-electrons and their volume dependence, we find that a small broadening of the liquid d-band width ({approx}1%) leads to an increase in the stability of the liquid relative to the solid. This is sufficient to depress the melting temperature and lower the melting slope to a value in agreement with the diamond-anvil cell measurements. Omission of the d-band physics results in an Al-like melting curve with a much steeper melt slope. The model, when applied to the f-electrons of the light actinides (Th-Am), gives agreement with the observed fall and rise in the melting temperature with increasing atomic number.
Date: June 25, 2004
Creator: Ross, M; Yang, L H & Boehler, R
Partner: UNT Libraries Government Documents Department