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Directed reflectivity, long life AMTEC condenser (DRC). Final report of Phase II SBIR program[Alkali Metal ThermoElectric Converter]

Directed reflectivity, long life AMTEC condenser (DRC). Final report of Phase II SBIR program[Alkali Metal ThermoElectric Converter]

Date: September 10, 2001
Creator: Hunt, Thomas K.
Description: The Alkali Metal Thermal to Electric Converter (AMTEC) is a static energy conversion device that operates at high thermal to electric conversion efficiencies that are essentially independent of size, have reached 19% and are expected to reach 25% to 30% in 1997. AMTEC systems have been chosen by NASA and DOE for spacecraft applications and have considerable promise for a wide variety of terrestrial applications. Reduction of parasitic heat losses in AMTEC systems related to radiative heat transfer from the hot side to the condenser can make a substantial contribution to system efficiency. Through design, analysis and the fabrication and testing of cells and systems, the proposed program to develop a Directed Reflectivity Condenser (DRC) has investigated the feasibility of an improved AMTEC condenser component. Phase 1 work showed the potential for adding from 4% to 7% to overall system efficiency for identical operating conditions using the concept. A detailed thermal analysis of several DRC capped cell designs was carried out and some of the conditions under which a DRC, used as the condenser at an end cap of a cylindrical converter, can reduce thermal radiation related losses were determined. A model experimental converter was built and tested to compare ...
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Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction

Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction

Date: February 7, 2011
Creator: Lu, T; Plomer, M; Luo, Z; Sarathy, S M; Pitz, W J; Som, S et al.
Description: Abstract not provided
Contributing Partner: UNT Libraries Government Documents Department
The Direction Cosine Method of Scatterer Location Extended to Spotlight-Mode IFSAR

The Direction Cosine Method of Scatterer Location Extended to Spotlight-Mode IFSAR

Date: October 26, 2000
Creator: EICHEL,PAUL H.
Description: In this paper we have shown how the direction cosine method of stripmap-mode IFSAR maybe modified for use in the spotlight-mode case. Spotlight-mode IFSAR geometry dictates a common aperture phase center, velocity vector, and baseline vector for every pixel in an image. Angle with respect to the velocity vector is the same for every pixel in a given column and can be computed from the column index, the Doppler of the motion compensation point and the Doppler column sample spacing used in image formation. With these modifications, the direction cosines and length of the line of sight vector to every scatterer in the scene may be computed directly from the raw radar measurements of range, Doppler, and interferometric phase.
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Direction-Preserving and Schur-Monotonic Semi-Separable Approximations of Symmetric Positive Definite Matrices}

Direction-Preserving and Schur-Monotonic Semi-Separable Approximations of Symmetric Positive Definite Matrices}

Date: March 16, 2010
Creator: Gu, M; Li, X S & Vassilevski, P S
Description: For a given symmetric positive definite matrix A {element_of} R{sup N x N}, we develop a fast and backward stable algorithm to approximate A by a symmetric positive-definite semi-separable matrix, accurate to a constant multiple of any prescribed tolerance. In addition, this algorithm preserves the product, AZ, for a given matrix Z {element_of} R{sup N x d}, where d << N. Our algorithm guarantees the positive-definiteness of the semi-separable matrix by embedding an approximation strategy inside a Cholesky factorization procedure to ensure that the Schur complements during the Cholesky factorization all remain positive definite after approximation. It uses a robust direction-preserving approximation scheme to ensure the preservation of AZ. We present numerical experiments and discuss potential implications of our work.
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Direction-Sensitive Hand-Held Gamma-Ray Spectrometer

Direction-Sensitive Hand-Held Gamma-Ray Spectrometer

Date: October 4, 2012
Creator: Mukhopadhyay, S.
Description: A novel, light-weight, hand-held gamma-ray detector with directional sensitivity is being designed. The detector uses a set of multiple rings around two cylindrical surfaces, which provides precise location of two interaction points on two concentric cylindrical planes, wherefrom the source location can be traced back by back projection and/or Compton imaging technique. The detectors are 2.0 × 2.0 mm europium-doped strontium iodide (SrI2:Eu2+) crystals, whose light output has been measured to exceed 120,000 photons/MeV, making it one of the brightest scintillators in existence. The crystal’s energy resolution, less than 3% at 662 keV, is also excellent, and the response is highly linear over a wide range of gamma-ray energies. The emission of SrI2:Eu2+ is well matched to both photo-multiplier tubes and blue-enhanced silicon photodiodes. The solid-state photomultipliers used in this design (each 2.0 × 2.0 mm) are arrays of active pixel sensors (avalanche photodiodes driven beyond their breakdown voltage in reverse bias); each pixel acts as a binary photon detector, and their summed output is an analog representation of the total photon energy, while the individual pixel accurately defines the point of interaction. A simple back-projection algorithm involving cone-surface mapping is being modeled. The back projection for an event cone ...
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Directional dependency of air sampling; Research and development grant {number_sign}4

Directional dependency of air sampling; Research and development grant {number_sign}4

Date: January 15, 1994
Creator: unknown
Description: A field study was performed by Idaho State University-Environmental Monitoring Laboratory (EML) to examine the directional dependency of low-volume air samplers. A typical continuous low volume air sampler contains a sample head that is mounted on the sampler housing either horizontally through one of four walls or vertically on an exterior wall `looking down or up.` In 1992, a field study was undertaken to estimate sampling error and to detect the directional effect of sampler head orientation. Approximately 1/2 mile downwind from a phosphate plant (continuous source of alpha activity), four samplers were positioned in identical orientation alongside one sampler configured with the sample head `looking down`. At least five consecutive weekly samples were collected. The alpha activity, beta activity, and the Be-7 activity collected on the particulate filter were analyzed to determine sampling error. Four sample heads were than oriented to the four different horizontal directions. Samples were collected for at least five weeks. Analysis of the alpha data can show the effect of sampler orientation to a know near source term. Analysis of the beta and Be-7 activity shows the effect of sampler orientation to a ubiquitous source term.
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Directional Extreme Wind Speed Data for the Design of Buildings and Other Structures

Directional Extreme Wind Speed Data for the Design of Buildings and Other Structures

Date: March 1984
Creator: Changery, Michael J.; Dumitriu-Valcea, Eugene J. & Simiu, Emil
Description: Report issued by the National Bureau of Standards over wind speed data collected for the design of buildings. The wind speed data is discussed. This report includes tables.
Contributing Partner: UNT Libraries Government Documents Department
Directional muon jet chamber for a muon collider (Groovy Chamber)

Directional muon jet chamber for a muon collider (Groovy Chamber)

Date: October 1, 1996
Creator: Atac, M.
Description: A directional jet drift chamber with PAD readout is proposed here which can select vertex originated muons within a given time window and eliminate those muons which primarily originate upstream, using only a PAD readout. Drift time provides the Z-coordinate, and the center of gravity of charge distribution provides the r-{psi} coordinates. Directionality at the trigger level is obtained by the timing measurement from the PAD hits within a given time window. Because of the long drift time between the bunch crossings, a muon collider enables one to choose a drift distance in the drift chamber as long as 50 cm. This is an important factor in reducing cost of drift chambers which have to cover relatively large areas.
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Directional Ordering and Dynamics in Dusty Plasmas

Directional Ordering and Dynamics in Dusty Plasmas

Date: May 24, 1999
Creator: Hammerberg, J. E.; Holian, B. L.; Murillo, M. S. & Winske, D.
Description: We use molecular dynamics (MD) simulation methods to investigate dusty plasma crystal structure, with the grains subject to a spherically symmetric Debye-Hueckel potential, a uni-directional external potential and an asymmetric wake potential. The structure is studied as a function of Mach number and magnitude of the wake as well as the strength of the rf input power, using parameters from a self-consistent dust-sheath model.
Contributing Partner: UNT Libraries Government Documents Department
Directional Shear Force Microscopy

Directional Shear Force Microscopy

Date: October 3, 2000
Creator: Burns, A. R. & Carpick, R. W.
Description: No abstract prepared.
Contributing Partner: UNT Libraries Government Documents Department
Directional stability characteristics of two types of tandem helicopter fuselage models

Directional stability characteristics of two types of tandem helicopter fuselage models

Date: May 1, 1954
Creator: Williams, James L
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Directional Stability of Towed Airplanes

Directional Stability of Towed Airplanes

Date: January 1, 1956
Creator: Soehne, W.
Description: So far, very careful investigations have been made regarding the flight properties, in particular the static and dynamic stability, of engine-propelled aircraft and of untowed gliders. In contrast, almost no investigations exist regarding the stability of airplanes towed by a towline. Thus, the following report will aim at investigating the directional stability of the towed airplane and, particularly, at determining what parameters of the flight attitude and what configuration properties affect the stability. The most important parameters of the flight attitude are the dynamic pressure, the aerodynamic coefficients of the flight attitude, and the climbing angle. Among the configuration properties, the following exert the greatest influence on the stability: the tow-cable length, the tow-cable attachment point, the ratio of the wing loadings of the towing and the towed airplanes, the moments of inertia, and the wing dihedral of the towed airplane. In addition, the size and shape of the towed airplane vertical tail, the vertical tail length, and the fuselage configuration are decisive factors in determining the yawing moment and side force due to sideslip, respectively.
Contributing Partner: UNT Libraries Government Documents Department
Directional Stand-off Detection of Fast Neutrons and Gammas Using Angular Scattering Distributions

Directional Stand-off Detection of Fast Neutrons and Gammas Using Angular Scattering Distributions

Date: October 25, 2009
Creator: e., Vanier P.; Dioszegi, I.; Salwen, C. & Forman, L.
Description: We have investigated the response of a DoubleScatter Neutron Spectrometer (DSNS) for sources at long distances (gr than 200 meters). We find that an alternative method for analyzing double scatter data avoids some uncertainties introduced by amplitude measurements in plastic scintillators.Time of flight is used to discriminate between gamma and neutron events, and the kinematic distributions of scattering angles are assumed to apply. Non-relativistic neutrons are most likely to scatter at 45°, while gammas with energies greater than 2 MeV are most likely to be forward scattered. The distribution of scattering angles of fission neutrons arriving from a distant point source generates a 45° cone, which can be back-projected to give the source direction. At the same time, the distribution of Compton-scattered gammas has a maximum in the forward direction, and can be made narrower by selecting events that deposit minimal energy in the first scattering event. We have further determined that the shape of spontaneous fission neutron spectra at ranges gr than 110 m is still significantly different from thecosmic ray background.
Contributing Partner: UNT Libraries Government Documents Department
Directional wind-measurement derived from elastic backscatter lidar data in real-time

Directional wind-measurement derived from elastic backscatter lidar data in real-time

Date: April 1, 1996
Creator: Moore, D.S.; White, S.W.; Karl, R.R. Jr. & Newnam, B.E.
Description: The development of a capability to infer wind velocities simultaneously at a number of ranges along one direction in real time is described. The elastic backscatter lidar data used was obtained using the XM94 lidar, developed by Los Alamos National Laboratory for the US Army Chemical and Biological Detection Command. In some respects this problem is simpler than measuring wind velocities on meso-meteorological scales. Other requirements, particularly high temporal fidelity, have driven the development of faster software algorithms and suggested opportunities for the evolution of the hardware.
Contributing Partner: UNT Libraries Government Documents Department
Directions for advanced use of nuclear power in century XXI

Directions for advanced use of nuclear power in century XXI

Date: May 1, 1999
Creator: Walter, C E
Description: Nuclear power can provide a significant contribution to electricity generation and meet other needs of the world and the US during the next century provided that certain directions are taken to achieve its public acceptance. These directions include formulation of projections of population, energy consumption, and energy resources over a responsible period of time. These projections will allow assessment of cumulative effects on the environment and on fixed resources. Use of fossil energy resources in a century of growing demand for energy must be considered in the context of long-term environmental damage and resource depletion. Although some question the validity of these consequences, they can be mitigated by use of advanced fast reactor technology. It must be demonstrated that nuclear power technology is safe, resistant to material diversion for weapon use, and economical. An unbiased examination of all the issues related to energy use, especially of electricity, is an essential direction to take.
Contributing Partner: UNT Libraries Government Documents Department
Directions for Sampling Coal for Shipment or Delivery

Directions for Sampling Coal for Shipment or Delivery

Date: June 1917
Creator: Pope, George S.
Description: Technical paper issued by the Bureau of Mines with instructions for coal sampling for shipment. As stated in the introduction, "this paper deals with the sampling of coal after it has been mined" (p. 5). This paper includes illustrations.
Contributing Partner: UNT Libraries Government Documents Department
Directions of ICF research in the United States

Directions of ICF research in the United States

Date: August 1, 1997
Creator: Hogan, W.J. & Campbell, M.A.
Description: Inertial Confinement Fusion (ICF) research in the United States is in a dramatic upswing. Technical progress continues at a rapid pace and with the start of construction of the National Ignition Facility (NIF) this year the total U.S. budget for ICF for fiscal year 1997 stands at $380 million. The NIF is being built as an essential component of the U.S. Stockpile Stewardship and Management Program, which has been formulated to assure the continued safety, reliability and performance of the downsized nuclear weapons stockpile in the absence of nuclear tests. Thus the increase in funding originates in the Congressional armed services committees and is managed by Defense Programs of the Department of Energy. The NIF, however, is a fundamental research tool that will be of great benefit beyond its mission within the nuclear weapons program. Its experiments will promote fusion energy development and will open new areas of basic scientific research. This paper will discuss some of the directions that ICF research is now taking, the progress on the NIF Project, and the potential impact that these developments are likely to have on fusion energy development and on certain areas of the basic sciences.
Contributing Partner: UNT Libraries Government Documents Department
Directly labeled fluorescent DNA probes for chromosome mapping

Directly labeled fluorescent DNA probes for chromosome mapping

Date: December 31, 1995
Creator: Marrone, B.L.; Deaven, L.L.; Chen, D.J.; Park, Min S.; MacInnes, M.A.; Salzman, G.C. et al.
Description: A new strategy is briefly described for employing nucleic acid probes that are directly labeled with fluorochromes in fluorescence in situ hybridization techniques. These probes will permit the detection, quantitation, and high-precision spatial analysis of multiple DNA sequences along a single chromosome using video-enhanced fluorescence microscopy and digital image processing and analysis. Potential advantages of direct labeled DNA probes for fluorescence in situ hybridization far surpass currently available, indirect DNA probe labeling techniques in ease of use, versatility, and increased signal- to-noise ratio.
Contributing Partner: UNT Libraries Government Documents Department
Directly Susceptible, Noncarbon Composite Crucible

Directly Susceptible, Noncarbon Composite Crucible

Date: November 25, 1998
Creator: Holcombe, Cressie E.,Jr.; Kiggans, James O., Jr.; Morrow, Marvin S. & Rexford, Donald
Description: A sintered metal ceramic crucible suitable for high temperature induction melting of reactive metals without appreciable carbon or silicon contamination of the melt. The crucible comprises a cast matrix of a thermally conductive ceramic material; a perforated metal sleeve, which serves as a susceptor for induction heating of the crucible, embedded within the ceramic cast matrix; and a thermal-shock-absorber barrier interposed between the metal sleeve and the ceramic cast matrix to allow for differential thermal expansions between the matrix and the metal sleeve and to act as a thermal-shock-absorber which moderates the effects of rapid changes of sleeve temperature on the matrix.
Contributing Partner: UNT Libraries Government Documents Department
The Director of National Intelligence and Intelligence Analysis

The Director of National Intelligence and Intelligence Analysis

Date: February 11, 2005
Creator: Best Jr., Richard A
Description: The 9/11 Commission made a number of recommendations to improve the quality of intelligence analysis. A key recommendation was the establishment of a Director of National Intelligence (DNI) position to manage the national intelligence effort and serve as the principal intelligence adviser to the President — along with a separate director of the Central Intelligence Agency. Subsequently, the Intelligence Reform and Terrorism Prevention Act of 2004, P.L. 108-458, made the DNI the principal adviser to the President on intelligence and made the DNI responsible for coordinating communitywide intelligence estimates. Some observers note that separating the DNI from the analytical offices may complicate the overall analytical effort.
Contributing Partner: UNT Libraries Government Documents Department
Director of National Intelligence: Statutory Authorities

Director of National Intelligence: Statutory Authorities

Date: April 11, 2005
Creator: Best Jr., Richard A; Cumming, Alfred & Masse, Todd M
Description: In passing the Intelligence Reform and Terrorism Prevention Act of 2004 (P.L. 108-458) in late 2004, Congress approved the most comprehensive reform of the U.S. Intelligence Community since its establishment over 50 years ago. Principal among enacted changes was the establishment of a new position of the Director of National Intelligence (DNI) to manage the Intelligence Community. Some observers have questioned whether the new statute provides the DNI the necessary authorities to effectively manage the Community.
Contributing Partner: UNT Libraries Government Documents Department
Director of National Intelligence Statutory Authorities: Status and Proposals

Director of National Intelligence Statutory Authorities: Status and Proposals

Date: May 26, 2010
Creator: Best, Richard A., Jr. & Cumming, Alfred
Description: This report discusses the Director of National Intelligence (DNI) position created by the Intelligence Reform and Terrorism Prevention Act of 2004 (P.L. 108-458). It includes an overview of the authorities granted to the DNI by legislation in 2004 and later as well as the varying opinions of Congress regarding new DNI authorities, as well as related legislation from FY2010 through FY2012.
Contributing Partner: UNT Libraries Government Documents Department
Director of National Intelligence Statutory Authorities: Status and Proposals

Director of National Intelligence Statutory Authorities: Status and Proposals

Date: January 12, 2011
Creator: Best, Richard A., Jr. & Cumming, Alfred
Description: This report discusses the Director of National Intelligence (DNI) position created by the Intelligence Reform and Terrorism Prevention Act of 2004 (P.L. 108-458). It includes an overview of the authorities granted to the DNI by legislation in 2004 and later as well as the varying opinions of Congress regarding new DNI authorities, as well as related legislation from FY2010 through FY2012.
Contributing Partner: UNT Libraries Government Documents Department
Director of National Intelligence Statutory Authorities: Status and Proposals

Director of National Intelligence Statutory Authorities: Status and Proposals

Date: December 16, 2011
Creator: Best, Richard A., Jr.
Description: This report discusses the Director of National Intelligence (DNI) position created by the Intelligence Reform and Terrorism Prevention Act of 2004 (P.L. 108-458). It includes an overview of the authorities granted to the DNI by legislation in 2004 and later as well as the varying opinions of Congress regarding new DNI authorities, as well as related legislation from FY2010 through FY2012.
Contributing Partner: UNT Libraries Government Documents Department