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Dispersion of UO{sub 2}F{sub 2} aerosol and HF vapor in the operating floor during winter ventilation at the Paducah Gaseous Diffusion Plant

Dispersion of UO{sub 2}F{sub 2} aerosol and HF vapor in the operating floor during winter ventilation at the Paducah Gaseous Diffusion Plant

Date: December 30, 1996
Creator: Kim, S.H.; Chen, N.C.J.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W. & Carter, J.C.
Description: The gaseous diffusion process is currently employed at two plants in the US: the Paducah Gaseous Diffusion Plant and the Portsmouth Gaseous Diffusion Plant. As part of a facility-wide safety evaluation, a postulated design basis accident involving large line-rupture induced releases of uranium hexafluoride (UF{sub 6}) into the process building of a gaseous diffusion plant (GDP) is evaluated. When UF{sub 6} is released into the atmosphere, it undergoes an exothermic chemical reaction with moisture (H{sub 2}O) in the air to form vaporized hydrogen fluoride (HF) and aerosolized uranyl fluoride (UO{sub 2}F{sub 2}). These reactants disperse in the process building and transport through the building ventilation system. The ventilation system draws outside air into the process building, distributes it evenly throughout the building, and discharges it to the atmosphere at an elevated temperature. Since air is recirculated from the cell floor area to the operating floor, issues concerning in-building worker safety and evacuation need to be addressed. Therefore, the objective of this study is to evaluate the transport of HF vapor and UO{sub 2}F{sub 2} aerosols throughout the operating floor area following B-line break accident in the cell floor area.
Contributing Partner: UNT Libraries Government Documents Department
Dispersion-reduction technique using subcarrier multiplexing

Dispersion-reduction technique using subcarrier multiplexing

Date: October 18, 1995
Creator: Sargis, P. D.; Haigh, R. E. & McCammon, K. G.
Description: We have developed a novel dispersion-reduction technique using subcarrier multiplexing (SCM) which permits the transmission of multiple 2.5 Gbit/s data channels over hundreds of kilometers of conventional fiber-optic cable with negligible dispersion. Using a lithium niobate external modulator having a modulation bandwidth of 20 GHz, we are able to multiplex several high-speed data channels at a single wavelength. At the receiving end, we demultiplex the data and detect each channel using a 2-GHz bandwidth optical detector. All of the hardware in our system consists of off-the-shelf components and can be integrated to reduce the overall cost. We demonstrated our dispersion-reduction technique in a recent field trial by transmitting two 2.5 Gbit/s data channels over 90 km of commercially-installed single-mode fiber, followed by 210 km of spooled fiber. For comparison, we substituted the 300 km of fiber with equivalent optical attenuation. We also ran computer simulations to evaluate link behavior. Technical details and field trial results will be presented.
Contributing Partner: UNT Libraries Government Documents Department
Dispersion relationship for solid state instability growth and sensitivity to equation of state

Dispersion relationship for solid state instability growth and sensitivity to equation of state

Date: June 1, 1997
Creator: Colvin, J.D.; Wiley, L.G.; Chandler, E.A.; Remington, B.A. & Kalantar, D.H.
Description: We have derived an approximate analytical dispersion relation for solid state instability growth following the method of Mikaelian. I He starts with the general eigenvalue equation for the velocity of a perturbation on a finite-thickness fluid layer with surface tension and viscosity, and derives an exact solution numerically from det(M)=0, where M is an 8x8 matrix. He then derives an approximate solution analytically by substituting the inviscid eigenfunctions into the exact eigenvalue equation. The integrations yield a dispersion relation which is a polynomial in the growth rate.
Contributing Partner: UNT Libraries Government Documents Department
Dispersive Approximations for Hyperbolic Conservation Laws

Dispersive Approximations for Hyperbolic Conservation Laws

Date: December 1981
Creator: Lucier, Bradley J.
Description: Necessary and sufficient conditions are given so that the Sobolev-type partial differential equations generate a contraction semigroup. It is shown that any nonlinear contraction from L/sup 1/(R) to itself that preserves the integral and commutes with translations satisfies maximum and minimum principles. This lemma is applied to the solution operator S/sub t/ to give necessary and sufficient conditions that S/t/ satisfy a maximum principle, despite the dispersive nature. Sufficient conditions are given so that the solutions converge, as nu and beta tend to zero, to the entropy solution of the conservation law. A larger class of monotone finite-difference schemes for the numerical solution of the conservation law motivated by finite-difference discretizations of the Sobolev equations, is introduced, and convergence results are proved for methods in this class. The methods analyzed include some that were previously used to approximate the solution of a linear waterflood problem in petroleum engineering.
Contributing Partner: UNT Libraries Government Documents Department
Dispersive internal long wave models

Dispersive internal long wave models

Date: November 1, 1998
Creator: Camassa, R.; Choi, W.; Holm, D.D.; Levermore, C.D. & Lvov, Y.
Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This work is a joint analytical and numerical study of internal dispersive water wave propagation in a stratified two-layer fluid, a problem that has important geophysical fluid dynamics applications. Two-layer models can capture the main density-dependent effects because they can support, unlike homogeneous fluid models, the observed large amplitude internal wave motion at the interface between layers. The authors have derived new model equations using multiscale asymptotics in combination with the method they have developed for vertically averaging velocity and vorticity fields across fluid layers within the original Euler equations. The authors have found new exact conservation laws for layer-mean vorticity that have exact counterparts in the models. With this approach, they have derived a class of equations that retain the full nonlinearity of the original Euler equations while preserving the simplicity of known weakly nonlinear models, thus providing the theoretical foundation for experimental results so far unexplained.
Contributing Partner: UNT Libraries Government Documents Department
Dispersive Velocity Measurements in Heterogeneous Materials

Dispersive Velocity Measurements in Heterogeneous Materials

Date: December 1, 2000
Creator: Trott, W.M.; Castaneda, J.N.; O'Hare, J.J.; Baer, M.R.; Chhabildas, L.C.; Knudson, M.D. et al.
Description: In order to provide real-time data for validation of three dimensional numerical simulations of heterogeneous materials subjected to impact loading, an optically recording velocity interferometer system (ORVIS) has been adapted to a line-imaging instrument capable of generating precise mesoscopic scale measurements of spatially resolved velocity variations during dynamic deformation. Combining independently variable target magnification and interferometer fringe spacing, this instrument can probe a velocity field along line segments up to 15 mm in length. In high magnification operation, spatial resolution better than 10 {micro}m can be achieved. For events appropriate to short recording times, streak camera recording can provide temporal resolution better than 0.2 ns. A robust method for extracting spatially resolved velocity-time profiles from streak camera image data has been developed and incorporated into a computer program that utilizes a standard VISAR analysis platform. The use of line-imaging ORVIS to obtain measurements of the mesoscopic scale dynamic response of shocked samples has been demonstrated on several different classes of heterogeneous materials. Studies have focused on pressed, granular sugar as a simulant material for the widely used explosive HMX. For low-density (65% theoretical maximum density) pressings of sugar, material response has been investigated as a function of both impact velocity ...
Contributing Partner: UNT Libraries Government Documents Department
Dispersive water waves in one and two dimensions

Dispersive water waves in one and two dimensions

Date: August 1, 1997
Creator: Holm, D.D. & Camassa, R.A.
Description: This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). We derived and analyzed new shallow water equations for one-dimensional flows near the critical Froude number as well as related integrable systems of evolutionary nonlinear partial differential equations in one spatial dimension, while developing new directions for the mathematics underlying the integrability of these systems. In particular, we applied the spectrum generating equation method to create and study new integrable systems of nonlinear partial differential equations related to our integrable shallow water equations. We also investigated the solutions of these systems of equations on a periodic spatial domain by using methods from the complex algebraic geometry of Riemann surfaces. We developed certain aspects of the required mathematical tools in the course of this investigation, such as inverse scattering with degenerate potentials, asymptotic reduction of the angle representations, geometric singular perturbation theory, modulation theory and singularity tracking for completely integrable equations. We also studied equations that admit weak solutions, i.e., solutions with discontinuous derivatives in the form of comers or cusps, even though they are solutions of integrable models, a property that is often incorrectly assumed to imply smooth solution ...
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Dispersive wave processing: a model-based solution

Dispersive wave processing: a model-based solution

Date: October 1, 1996
Creator: Candy, J.V. & Chambers, D.C.
Description: Wave propagation through various media represents a significant problem in many applications in acoustics and electromagnetics especially when the medium is dispersive. We post a general dispersive wave propagation model that could easily represent many classes of dispersive waves and proceed to develop a model-based processor employing this underlying structure. The general solution to the model-based dispersive wave estimation problem is developed using the Bayesian maximum a posteriori approach which leads to the nonlinear extended Kalman filter processor.
Contributing Partner: UNT Libraries Government Documents Department
Dispersively enhanced bunching in high-gain free-electron lasers

Dispersively enhanced bunching in high-gain free-electron lasers

Date: February 1, 2000
Creator: Freund, H.P. & Neil, G.R.
Description: A free-electron laser using a multi-segment optical klystron (MSOK) is studied using a 3-D simulation code for use as 4th generation light sources. The MSOK consists of multiple wiggler segments with dipole triplets in the gaps. The dipole triplets impose a dogleg trajectory that ballistically enhances the electron beam bunching and the gain in the following wiggler segment. There are three principal advantages of the MSOK over single-segment wiggler designs. First, the saturation length is drastically reduced. Second, the MSOK is significantly less sensitive to beam energy spread. Third, the linewidth is carryover and can be tuned by varying the dipole field strength. As a result, the MSOK is an ideal configuration for 4th generation light sources.
Contributing Partner: UNT Libraries Government Documents Department
Dispersivity in heterogeneous permeable media

Dispersivity in heterogeneous permeable media

Date: January 1, 1994
Creator: Chesnut, D.A.
Description: When one fluid displaces another through a one-dimensional porous medium, the composition changes from pure displacing fluid at the inlet to pure displaced fluid some distance downstream. The distance over which an arbitrary percentage of this change occurs is defined as the mixing zone length, which increases with increasing average distance traveled by the displacement front. For continuous injection, the mixing zone size can be determined from a breakthrough curve as the time required for the effluent displacing fluid concentration to change from, say, 10% to 90%. In classical dispersion theory, the mixing zone grows in proportion to the square root of the mean distance traveled, or, equivalently, to the square root of the mean breakthrough time. In a multi-dimensional heterogeneous medium, especially at field scales, the size of the mixing zone grows almost linearly with mean distance or travel time. If an observed breakthrough curve is forced to fit the, clinical theory, the resulting effective dispersivity, instead of being constant, also increases almost linearly with the spatial or temporal scale of the problem. This occurs because the heterogeneity in flow properties creates a corresponding velocity distribution along the different flow pathways from the inlet to the outlet of the ...
Contributing Partner: UNT Libraries Government Documents Department
DISPL: a Software Package for One and Two Spatially Dimensioned Kinetics-Diffusion Problems

DISPL: a Software Package for One and Two Spatially Dimensioned Kinetics-Diffusion Problems

Date: November 1978
Creator: Leaf, G. K.; Minkoff, M.; Byrne, G. D.; Sorensen, D.; Bleakney, T. & Saltzman, J.
Description: DISPL is a software package for solving some second-order nonlinear systems of partial differential equations including parabolic, elliptic, hyperbolic, and some mixed types such as parabolic-elliptic equations. Fairly general nonlinear boundary conditions are allowed as well as interface conditions for problems in an inhomogeneous media. The spatial domain is one- or two-dimensional with Cartesian, cylindrical, or spherical (in one dimension only) geometry. The numerical method is based on the use of Galerkin's procedure combined with the use of B-splines in order to reduce the system of PDE's to a system of ODE's. The latter system is then solved with a sophisticated ODE software package. Software features include extensive dump/restart facilities, free format input, moderate printed output capability, dynamic storage allocation, and three graphics packages.
Contributing Partner: UNT Libraries Government Documents Department
DISPL1: a Software Package for One and Two Spatially Dimensioned Kinetics-Diffusion Problems

DISPL1: a Software Package for One and Two Spatially Dimensioned Kinetics-Diffusion Problems

Date: September 1984
Creator: Leaf, Gary K. & Minkoff, Michael
Description: DISPL1 is a software package for solving some second order nonlinear systems of partial differential equations including parabolic, elliptic, hyperbolic, and some mixed types such as parabolic-elliptic equations. Fairly general nonlinear boundary conditions are allowed as well as interface conditions for problems in an inhomogeneous media. The spatial domain is one or two dimensional with Cartesian, cylindrical, or spherical (in one dimension only) geometry. The numerical method is based on the use of Galerkin's procedure combined with the use of B-splines in order to reduce the system of PDE's to a system of ODE's. The latter system is then solved with a sophisticated ODE software package. Software features include extensive dump/restart facilities, free format input, moderate printed output capability, dynamic storage allocation, and three graphics packages.
Contributing Partner: UNT Libraries Government Documents Department
Displaced Homemakers: Programs and Policy: An Interim Report

Displaced Homemakers: Programs and Policy: An Interim Report

Date: October 1985
Creator: United States. Congress. Office of Technology Assessment.
Description: A report by the Office of Technology Assessment (OTA) that focuses on the "problems of and programs for displaced homemakers" (p. iii).
Contributing Partner: UNT Libraries Government Documents Department
Displaced Iraqis: Integrated International Strategy Needed to Reintegrate Iraq's Internally Displaced and Returning Refugees

Displaced Iraqis: Integrated International Strategy Needed to Reintegrate Iraq's Internally Displaced and Returning Refugees

Date: December 2, 2010
Creator: United States. Government Accountability Office.
Description: A letter report issued by the Government Accountability Office with an abstract that begins "The estimated number of Iraqis who have been internally displaced since February 2006 is about 1.6 million, and numerous Iraqis are in neighboring countries. Tens of thousands of Iraqi families have returned home and the number is slowly increasing. GAO examined (1) conditions in Iraq that pose a challenge to the reintegration of displaced Iraqis, (2) actions the international community is taking to address these conditions and reintegration, and (3) the extent to which the international community has an effective reintegration strategy. GAO analyzed reports and data, met with officials from the U.S. and Iraqi governments and international and nongovernmental organizations, and did fieldwork in Geneva and Baghdad."
Contributing Partner: UNT Libraries Government Documents Department
Displacement analysis of a bend plate test with mechanical loading and laser heating

Displacement analysis of a bend plate test with mechanical loading and laser heating

Date: September 1, 1997
Creator: Lam, P.S.
Description: The surface displacment of a steel plate caused by a permanent deformation as a result of local yielding was modeled by a finite element analysis. The local yielding occurs when a small area of the plate is heated by a laser beam. The calculated displacments are in good agreement with the preliminary experimental data obtained using a bend specimen with laser heating at the University of Alabama at Huntsville. It has been shown computuationally and optically that the relative displacments are less than 1mm near the laser heated area of the specimen. The results demonstrate that the experimental approach is a feasible technique for determining the residual stress under multiaxial stress field.
Contributing Partner: UNT Libraries Government Documents Department
Displacement Based Seismic Design Criteria

Displacement Based Seismic Design Criteria

Date: March 29, 1999
Creator: Costello, J.F.; Hofmayer, C. & Park, Y.J.
Description: The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.
Contributing Partner: UNT Libraries Government Documents Department
DISPLACEMENT BASED SEISMIC DESIGN CRITERIA

DISPLACEMENT BASED SEISMIC DESIGN CRITERIA

Date: March 29, 1999
Creator: HOFMAYER,C.H.
Description: The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.
Contributing Partner: UNT Libraries Government Documents Department
Displacement effect of a three-dimensional boundary layer

Displacement effect of a three-dimensional boundary layer

Date: January 1, 1953
Creator: Moore, Franklin K
Description: A method is described for determining the "displacement surface" of known three-dimensional compressible boundary-layer flow in terms of the mass-flow defects associated with the profiles of the two velocity components parallel to the surface. The result is a generalization of the plane flow concept of displacement thickness introduced in order to describe how a thin boundary layer distorts the outer nonviscous flow. Numerical values are found for the known three-dimensional boundary-layer flow about a cone at a small angle of attack to a supersonic stream.
Contributing Partner: UNT Libraries Government Documents Department
Displacement effect of a three-dimensional boundary layer

Displacement effect of a three-dimensional boundary layer

Date: June 1, 1952
Creator: Moore, Franklin K
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Displacements and rotations of a body moving about an arbitrary axis in a global reference frame

Displacements and rotations of a body moving about an arbitrary axis in a global reference frame

Date: November 1995
Creator: Hollerbach, K. & Hollister, A.
Description: Measurement of human joint motion frequently involves the use of markers to describe joint motion in a global reference frame. Results may be quite arbitrary if the reference frame is not properly chosen with respect to the joint`s rotational axis(es). In nature joint axes can exist at any orientation and location relative to an arbitrarily chosen global reference frame. An arbitrary axis is any axis that is not coincident with a reference coordinate. Calculations are made of the errors that result when joint motion occurs about an arbitrary axis in a global reference frame.
Contributing Partner: UNT Libraries Government Documents Department
Displacing Coal with Generation from Existing Natural Gas-Fired Power Plants

Displacing Coal with Generation from Existing Natural Gas-Fired Power Plants

Date: January 19, 2010
Creator: Kaplan, Stan M.
Description: This report provides an overview of the issues involved in displacing coal-fired generation with electricity from existing and underutilized natural gas plants in order to cut greenhouse gas emissions. Reducing carbon dioxide emissions from coal plants is a focus of many proposals for cutting greenhouse gas emissions.
Contributing Partner: UNT Libraries Government Documents Department
Display of the Confederate Flag at Federal Cemeteries

Display of the Confederate Flag at Federal Cemeteries

Date: July 10, 2015
Creator: Comay, Laura B. & Salazar Torreon, Barbara
Description: This report discusses policies regarding the display of the Confederate Flag at national cemeteries. If a state observes a Confederate Memorial Day, NPS cemeteries in the state may permit a sponsoring group to decorate the graves of Confederate veterans with small Confederate flags. Additionally, according to the National Park Service (NPS) reference manual, such flags may also be displayed on the nationally observed Memorial Day, to accompany the U.S. flag on the graves of Confederate veterans.
Contributing Partner: UNT Libraries Government Documents Department
Displaying drift scanning images from multiple CCDs in real-time during data acquisition

Displaying drift scanning images from multiple CCDs in real-time during data acquisition

Date: December 1, 1995
Creator: Nicinski, T.
Description: Drift scanning images from the Sloan Digital Sky Survey`s 54 CCD camera are displayed on eight screens in real-time during data acquisition. This real-time visual feedback provides an observer the means to quickly check data acquisition and telescope operations. The hardware and software used to accomplish this display are presented.
Contributing Partner: UNT Libraries Government Documents Department
Disposability Assessment: Aluminum-Based Spent Nuclear Fuel Forms

Disposability Assessment: Aluminum-Based Spent Nuclear Fuel Forms

Date: November 6, 1998
Creator: Vinson, D.W.
Description: This report provides a technical assessment of the Melt-Dilute and Direct Al-SNF forms in disposable canisters with respect to meeting the requirements for disposal in the Mined Geologic Disposal System (MGDS) and for interim dry storage in the Treatment and Storage Facility (TSF) at SRS.
Contributing Partner: UNT Libraries Government Documents Department