Serial/Series Title
Fiscal Year 2007
7
Fiscal Year 2002
5
Fiscal Year 2000
4
MUSC Environmental Biosciences Progress Report
4
OIT Tip Sheets
4
Science & Technology Review
4
ARM Facilities Newsletter
3
Development of On-line Instrumentation and Techniques to Detect and Measure Particulates Quarterly Report
3
Enhanced Coal Bed Methane Production and Sequestration of CO2 in Unmineable Coal Seams Progress Report
3
Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report
3
88 More
Country
States
Decade
Month
Language
6,020 Matching Results
Results open in a new window/tab.
Results:
1 - 24 of
6,020
next
USING BLOCKS OF SKEWERS FOR FASTER COMPUTATION OF PIXEL PURITY INDEX
The pixel purity index (PPI) algorithm proposed by Boardman, et al.1 identifies potential endmember pixels in multispectral imagery. The algorithm generates a large number of skewers (unit vectors in random directions), and then computes the dot product of each skewer with each pixel. The PPI is incremented for those pixels associated with the extreme values of the dot products. A small number of pixels (a subset of those with the largest PPI values) are selected as pure and the rest of the pixels in the image are expressed as linear mixtures of these pure endmembers. This provides a convenient and physically-motivated decomposition of the image in terms of a relatively few components. We report on a variant of the PPI algorithm in which blocks of B skewers are considered at a time. From the computation of B dot products, one can produce a much larger set of derived dot products that are associated with skewers that are linear combinations of the original B skewers. Since the derived dot products involve only scalar operations, instead of full vector dot products, they can be very cheaply computed. We will also discuss a hardware implementation on a field programmable gate array (FPGA) processor …
Date:
October 1, 2000
Creator:
Theiler, James; Lavenier, Dominique D.; Harvey, Neal R.; Perkins, Simon J. & Szymanski, John J.
Object Type:
Article
System:
The UNT Digital Library
ALGORITHMIC TRANSFORMS IN THE IMPLEMENTATION OF K-MEANS CLUSTERING ON RECONFIGURABLE HARDWARE
None
Date:
October 1, 2000
Creator:
Estlick, Michael; Leeser, Miriam; Szymanski, John J. & Theiler, James
Object Type:
Article
System:
The UNT Digital Library
Sensitivity and uncertainty analysis for nuclear criticality safety using KENO in the SCALE code system
Sensitivity and uncertainty methods have been developed to aid in the establishment of areas of applicability and validation of computer codes and nuclear data for nuclear criticality safety studies. A key component in this work is the generation of sensitivity and uncertainty parameters for typically several hundred benchmarks experiments used in validation exercises. Previously, only one-dimensional sensitivity tools were available for this task, which necessitated the remodeling of multidimensional inputs in order for such an analysis to be performed. This paper describes the development of the SEN3 Monte Carlo based sensitivity analysis sequence for SCALE. Two options in the SEN3 package for the reconstruction of angular-dependent forward and adjoint fluxes are described and contrasted. These options are the direct calculation of flux moments versus the calculation of angular fluxes, with subsequent conversion to flux moments prior to sensitivity coefficient generation. The latter technique is found to be significantly more efficient.
Date:
October 1, 2000
Creator:
Rearden, Bradley T.
Object Type:
Article
System:
The UNT Digital Library
Gas Phase Chemical Detection with an Integrated Chemical Analysis System
None
Date:
October 9, 2000
Creator:
Casalnuovo, S. A.; Frye-Mason, G. C.; Kottenstette, R.; Heller, E. J.; Matzke, C. M.; Lewis, P. R. et al.
Object Type:
Article
System:
The UNT Digital Library
First Principles Applied to Software Safety - The Novel Use of Silicon Machinery
None
Date:
October 20, 2000
Creator:
Dalton, Larry J.
Object Type:
Article
System:
The UNT Digital Library
Integrated Micro-Machined Hydrogen Gas Sensor. Final Report
This report details our recent progress in developing novel MEMS (Micro-Electro-Mechanical Systems) based hydrogen gas sensors. These sensors couple novel thin films as the active layer on a device structure known as a Micro-HotPlate. This coupling has resulted in a gas sensor that has several unique advantages in terms of speed, sensitivity, stability and amenability to large scale manufacture. This Phase-I research effort was focused on achieving the following three objectives: (1) Investigation of sensor fabrication parameters and their effects on sensor performance. (2) Hydrogen response testing of these sensors in wet/dry and oxygen-containing/oxygen-deficient atmospheres. (3) Investigation of the long-term stability of these thin film materials and identification of limiting factors. We have made substantial progress toward achieving each of these objectives, and highlights of our phase I results include the demonstration of signal responses with and without oxygen present, as well as in air with a high level of humidity. We have measured response times of <0.5 s to 1% H{sub 2} in air, and shown the ability to detect concentrations of <200 ppm. These results are extremely encouraging and suggest that this technology has substantial potential for meeting the needs of a hydrogen based economy. These achievements demonstrate …
Date:
October 2, 2000
Creator:
Frank DiMeo, Jr.
Object Type:
Report
System:
The UNT Digital Library
Final Report: Illinois Institjute of Technology Antifoam Recommendation to SRTC
This report is a summary of the basic research necessary to understand the cause of foaming in the Small Tank Tetraphenylborate Process (STTP) and to develop a short list of antifoaming and defoaming agents.
Date:
October 17, 2000
Creator:
Lambert, D. P.
Object Type:
Report
System:
The UNT Digital Library
Rapid Discovery of Materials
None
Date:
October 1, 2001
Creator:
LOY, DOUGLAS A.; SOTO, ELI E. & WHEELER, DAVID R.
Object Type:
Report
System:
The UNT Digital Library
Development of dense ceramic membranes for hydrogen separation.
None
Date:
October 18, 2001
Creator:
Balachandran, U.; Lee, T. H.; Wang, S.; Dorris, S. E. & Rothenberger, K. S.
Object Type:
Article
System:
The UNT Digital Library
Studies of Band Structure and Free Carrier Scattering in Transparent Conducting Oxides Based on Combined Measurements of Electron Transport Phenomena
Experimental methods are discussed for studying band structure, effective mass, and other electronic properties relevant to mobility, including scattering mechanisms, relaxation time, and the influence of grain boundaries (GBs) in polycrystalline transparent conducting oxide (TCO) films. Impedance spectroscopy permits evaluation of the GB potential barrier height and density-of-states. These studies enable an estimate of the limiting mobility achievable for practical transparent conducting oxides to be made. The equipment for measurement of the four transport coefficients is discussed, and examples of its application to films of ZnO, SnO2, and Cd2SnO4 are given.
Date:
October 31, 2000
Creator:
Kaydanov, V. I.; Coutts, T. J. & Young, D. L.
Object Type:
Article
System:
The UNT Digital Library
The Influence of Coating Structure on Micromachine Stiction
We have clearly shown that the film morphology dictates the anti-stiction properties of FDTS coatings. Release stiction is not observed when ideal monolayer films are present but can be extensive when thicker aggregate structures are present. This finding is significant because it indicates that agglomerate formation during processing is a major source of irreproducible behavior when FDTS coatings are used to release micromachined parts. The results could also help explain why coatings that are aged at high. humidity start to stick to each other. (AFM results show that humid environments promote the formation of aggregates from monolayer films.) The reason why aggregate structures promote stiction is currently unknown. However, it appears that aggregates interfere with the ability of FDTS to form dense, well-ordered coatings under microstructures, leading to surfaces that are sufficiently hydrophilic to allow for release stiction via an attractive Laplace force during drying.
Date:
October 3, 2000
Creator:
Kushmerick, J. G.; Hankins, M. G.; De Boer, M. P.; Clews, P. J.; Carpick, R. W. & Bunker, B. C.
Object Type:
Article
System:
The UNT Digital Library
Stiff Temperature Profiles in JT-60U ELMy H-mode Plasmas
The 'stiffness' of thermal transport in ELMy H-modes [edge localized high-confinement modes] is examined in a series of carefully chosen JT-60U plasmas, and measured temperatures are compared with the predictions of several transport models. A heating power scan with constant T(subscript ''ped''), a scan of pedestal temperature, T(subscript ''ped''), with constant heating power, and an on-axis/off-axis heating comparison are presented. In the power scan a 45% increase in heating (and a 12% density rise) produces an approximately fixed core temperature profile in a group of five plasmas with the same pedestal temperature. With fixed heating power, we find that a 30-40% increase in T(subscript ''ped'') is associated with similar increases in core temperature. Heating in the deep core is varied by employing different groups of neutral beams that deposit their power near the magnetic axis and farther from the axis. In these plasmas, on-axis heating produces slightly more peaked temperature profiles, although they have 60% more heating power inside r = a/2. Transport models are tested by solving the power balance equations to predict temperatures, which are then compared to the measurements. Predictions of the RLWB and IFS/PPPL models generally agree with the measured temperatures outside r approximately 0.3a, but …
Date:
October 16, 2001
Creator:
Mikkelsen, D.R.; Urano, H.; Shirai, H.; Takizuka, T.; Kamada, Y.; Hatae, T. et al.
Object Type:
Report
System:
The UNT Digital Library
Alternative Landfill Cover Demonstration, FY2000 Annual Data Report
None
Date:
October 1, 2000
Creator:
Dwyer, Stephen F.; Reavis, Bruce A. & Newman, Gretchen
Object Type:
Report
System:
The UNT Digital Library
Industry Teams with National Laboratories to Develop a Predictive Model for Powder Pressing and Die Design
None
Date:
October 3, 2000
Creator:
Ewsuk, K. G.; Arguello, J. G., Jr.; Zeuch, D. H.; Farber, B.; Carinci, L.; Kaniuk, J. et al.
Object Type:
Article
System:
The UNT Digital Library
Experimental Study of Ion Heating and Acceleration During Magnetic Reconnection
Ion heating and acceleration has been studied in the well-characterized reconnection layer of the Magnetic Reconnection Experiment [M. Yamada et al., Phys. Plasmas 4, 1936 (1997)]. Ion temperature in the layer rises substantially during null-helicity reconnection in which reconnecting field lines are anti-parallel. The plasma out flow is sub-Alfvonic due to a downstream back pressure. An ion energy balance calculation based on the data and including classical viscous heating indicates that the ions are heated largely due to non-classical mechanisms. The Ti rise is much smaller during co-helicity reconnection in which field lines reconnect obliquely. This is consistent with a slower reconnection rate and a smaller resistivity enhancement over the Spitzer value. These observations indicate strongly that non-classical dissipation mechanisms can play an important role both in heating the ions and in facilitating the reconnection process.
Date:
October 24, 2000
Creator:
Hsu, S.C.; Carter, T.A.; Fiksel, G.; Ji, H.; Kulsrud, R.M. & Yamada, M.
Object Type:
Report
System:
The UNT Digital Library
Economic Energy Savings Potential in Federal Buildings
None
Date:
October 4, 2000
Creator:
Brown, D. R.; Dirks, J. A. & Hunt, D. M.
Object Type:
Report
System:
The UNT Digital Library
Summary of Hanford Site Environmental Report for Calendar Year 2000
This booklet summarizes the Hanford Site Environmental Report for Calendar Year 2000. The Hanford Site environmental report is prepared annually to summarize environmental data and information, describe environmental management performance, demonstrate the status of compliance with environmental regulations, and highlight major environmental programs and efforts. The document is written to meet requirements and guidelines of the US Department of Energy (DOE) and the needs of the public. This summary booklet is designed to briefly (1) describe the Hanford Site and its mission; (2) describe environmental programs at the Hanford Site; (3) discuss estimated radionuclide exposures to the public from 2000 Hanford Site activities; (4) summarize the status of compliance with environmental regulations; and (5) present information on environmental monitoring and surveillance and groundwater protection and monitoring. Readers interested in more detailed information can consult the 2000 report or the technical documents cited and listed in that report.
Date:
October 2001
Creator:
Hanf, Robert W., Jr.; Poston, Ted M.; Oconnor, G. A. & Morasch, Launa F.
Object Type:
Report
System:
The UNT Digital Library
Improved Radiometric Calibrations and Measurements for Evaluating Photovoltaic Devices
The Photovoltaic Radiometric Measurements Task has improved broadband and spectral measurement capabilities at NREL. These improved NREL's capabilities affect the Photovoltaic Module and Array Performance and Reliability and Photovoltaic Measurements and Characterization Projects. Recent improvements (during 2000) in broadband radiometer calibrations result in the removal of bias errors on the order of 20 watts per square meter (W/m{sup 2}) in the measurement of global-hemispherical solar radiation. The improvements described are partially due to technical interactions by members of the Measurements and Instrumentation Team with the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM), National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) Validation Program, World Meteorological Organization (WMO) Baseline Surface Measurement Network (BSRN), and National Oceanic and Atmospheric Administration (NOAA) Solar Radiation Research Branch (SRRB). New equipment has been purchased and techniques have been developed to characterize pulsed solar simulator spectral distributions. New equipment has been purchased and will be installed in the redesigned Solar Radiation Research Laboratory (SRRL) Baseline Measurement System (BMS). Expanded measurement capability, including sky radiance mapping, extensive ultraviolet and infrared radiation measurements, and routine spectral sampling will provide a unique complement of data for investigating PV device, module, and system design and performance, model …
Date:
October 16, 2000
Creator:
Myers, D.; Stoffel, T.; Andreas, A.; Wilcox, S. & Reda, I.
Object Type:
Report
System:
The UNT Digital Library
The Savannah River Site's Groundwater Monitoring Program - Fourth Quarter 1999 (October through December 1999)
This report summarizes the Groundwater Monitoring Program conducted by the Savannah River site during fourth quarter 1999. It includes the analytical data, field data, data review, quality control, and other documentation for this program; provides a record of the program's activities; and serves as an official records of the analytical results.
Date:
October 12, 2000
Creator:
Hutchison, J.B.
Object Type:
Report
System:
The UNT Digital Library
Emittance measurements at the A0 photo-injector
The A0 photo-injector produces electron bunches of 1--14 nC charge with an energy of 18 MeV. Detailed measurements and optimization of emittance have been carried out for a number of gun and laser operating conditions, beam line optics conditions, and at a number of beam line locations. Results are compared with the predictions of simulations using HOMDYN.
Date:
October 10, 2000
Creator:
Carneiro, Jean-Paul
Object Type:
Article
System:
The UNT Digital Library
Rare K+ Decays from Experiment E787
This paper presents the latest results from experiment E787, at Brookhaven National Laboratory, on K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}} and radiative K{sup +} decays. The result for K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}} uses data collected in runs taken during 1995, 1996 and 1997. In addition, they discuss plans for future measurements of K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}}.
Date:
October 9, 2000
Creator:
Jain, V.
Object Type:
Article
System:
The UNT Digital Library
Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control -- Part I: Theory and Simulation
An inverter topology and control scheme has been developed that can drive low-inductance, surface-mounted permanent magnet motors over the wide constant power speed range required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC) [1]. The DMIC can drive either the Permanent Magnet Synchronous Machine (PMSM) with sinusoidal back emf, or the brushless dc machine (BDCM) with trapezoidal emf in the motoring and regenerative braking modes. In this paper we concentrate on the BDCM under high-speed motoring conditions. Simulation results show that if all motor and inverter loss mechanisms are neglected, the constant power speed range of the DMIC is infinite. The simulation results are supported by closed form expressions for peak and rms motor current and average power derived from analytical solution to the differential equations governing the DMIC/BDCM drive for the lossless case. The analytical solution shows that the range of motor inductance that can be accommodated by the DMIC is more than an order of magnitude such that the DMIC is compatible with both low- and high-inductance BDCMs. Finally, method is given for integrating the classical hysteresis band current control, used for motor control below base speed, with the phase advance of …
Date:
October 29, 2001
Creator:
Lawler, J.S.
Object Type:
Article
System:
The UNT Digital Library
Effective Cleaning Radius Studies
This report discusses results of testing done in the Savannah River Laboratory half tank and full tank mockup facilities using kaolin clay slurries and the relationship between cleaning radius and pump and slurry characteristics.
Date:
October 15, 2001
Creator:
Churnetski, B. V.
Object Type:
Report
System:
The UNT Digital Library
Inorganic and Radiochemical Analysis of 241-C-104 Tank Waste
None
Date:
October 25, 2000
Creator:
Fiskum, S. K.; Barinaga, C. J.; Bramson, J. P.; Carson, K. J.; Deschane, J. R.; Farmer, O. T. et al.
Object Type:
Report
System:
The UNT Digital Library