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Generalization of Spatial Channel Theory to Three-Dimensional x-y-z Transport Computations
Spatial channel theory, initially introduced in 1977 by M. L. Williams and colleagues at ORNL, is a powerful tool for shield design optimization. It focuses on so called ''contributon'' flux and current of particles (a fraction of the total of neutrons, photons, etc.) which contribute directly or through their progeny to a pre-specified response, such as a detector reading, dose rate, reaction rate, etc., at certain locations of interest. Particles that do not contribute directly or indirectly to the pre-specified response, such as particles that are absorbed or leak out, are ignored. Contributon fluxes and currents are computed based on combined forward and adjoint transport solutions. The initial concepts were considerably improved by Abu-Shumays, Selva, and Shure by introducing steam functions and response flow functions. Plots of such functions provide both qualitative and quantitative information on dominant particle flow paths and identify locations within a shield configuration that are important in contributing to the response of interest. Previous work was restricted to two dimensional (2-D) x-y rectangular and r-z cylindrical geometries. This paper generalizes previous work to three-dimensional x-y-z geometry, since it is now practical to solve realistic 3-D problems with multidimensional transport programs. As in previous work, new analytic …
Date:
March 12, 2002
Creator:
Abu-Shumays, I. K.; Hunter, M. A.; Martz, R. L. & Risner, J. M.
Object Type:
Article
System:
The UNT Digital Library
Calibrated Properties Model
The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the ''AMR Development Plan for U0035 Calibrated Properties Model REV00. These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.
Date:
March 12, 2000
Creator:
Ahlers, C. & Liu, H.
Object Type:
Report
System:
The UNT Digital Library
Timpson & Tenaha News (Timpson, Tex.), Vol. 27, No. 10, Ed. 1 Thursday, March 12, 2009
Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.
Date:
March 12, 2009
Creator:
Alexander, Nancy
Object Type:
Newspaper
System:
The Portal to Texas History
Laser Ion Acceleration from the Interaction of Ultra-Intense laser Pulse with thi foils
The discovery that ultra-intense laser pulses (I > 10{sup 18} W/cm{sup 2}) can produce short pulse, high energy proton beams has renewed interest in the fundamental mechanisms that govern particle acceleration from laser-solid interactions. Experiments have shown that protons present as hydrocarbon contaminants on laser targets can be accelerated up to energies > 50 MeV. Different theoretical models that explain the observed results have been proposed. One model describes a front-surface acceleration mechanism based on the ponderomotive potential of the laser pulse. At high intensities (I > 10{sup 18} W/cm{sup 2}), the quiver energy of an electron oscillating in the electric field of the laser pulse exceeds the electron rest mass, requiring the consideration of relativistic effects. The relativistically correct ponderomotive potential is given by U{sub p} = ([1 + I{lambda}{sup 2}/1.3 x 10{sup 18}]{sup 1/2} - 1) m{sub o}c{sup 2}, where I{lambda}{sup 2} is the irradiance in W{micro}m{sup 2}/cm{sup 2} and m{sub o}c{sup 2} is the electron rest mass.At laser irradiance of I{lambda}{sup 2} {approx} 10{sup 20} W{micro}m{sup 2}/cm{sup 2}, the ponderomotive potential can be of order several MeV. A few recent experiments--discussed in Chapter 3 of this thesis--consider this ponderomotive potential sufficiently strong to accelerate protons from the …
Date:
March 12, 2004
Creator:
Allen, M
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 105, No. 309, Ed. 1 Friday, March 12, 2004
Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date:
March 12, 2004
Creator:
Andrews, Mike
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Development and Application of a Strength and Damage Model for Rock under Dynamic Loading
Simulating the behavior of geologic materials under impact loading conditions requires the use of a constitutive model that includes the effects of bulking, yielding, damage, porous compaction and loading rate on the material response. This paper describes the development, implementation and calibration of a thermodynamically consistent constitutive model that incorporates these features. The paper also describes a computational study in which the model was used to perform numerical simulations of PILE DRIVER, a deeply-buried underground nuclear explosion detonated in granite at the Nevada Test Site. Particle velocity histories, peak velocity and peak displacement as a function of slant range obtained from the code simulations compare favorably with PILE DRIVER data. The simulated attenuation of peak velocity and peak displacement also agrees with the results from several other spherical wave experiments in granite.
Date:
March 12, 2001
Creator:
Antoun, T H; Lomov, I N & Glenn, L A
Object Type:
Article
System:
The UNT Digital Library
Ferromagnetism and suppression of metallic clusters in Fe implanted ZnO -- a phenomenon related to defects?
We investigated ZnO(0001) single crystals annealed in high vacuum with respect to their magnetic properties and cluster formation tendency after implant-doping with Fe. While metallic Fe cluster formation is suppressed, no evidence for the relevance of the Fe magnetic moment to the observed ferromagnetism was found. The latter along with the cluster suppression is discussed with respect to defects in the ZnO host matrix, since the crystalline quality of the substrates was lowered due to the preparation as observed by x-ray diffraction.
Date:
March 12, 2008
Creator:
Arenholz, Elke; Zhou, S.; Potzger, K.; Talut, G.; Reuther, H.; Kuepper, K. et al.
Object Type:
Article
System:
The UNT Digital Library
The Ignition Target for the National Ignition Facility
The National Ignition Facility (NIF) is a 192 beam Nd-glass laser facility presently under construction at Lawrence Livermore National Laboratory (LLNL) for performing inertial confinement fusion (ICF) and experiments studying high energy density (HED) science. When completed in 2009, NIF will be able to produce 1.8 MJ, 500 TW of ultraviolet light for target experiments that will create conditions of extreme temperatures (>10{sup 8} K), pressures (10-GBar) and matter densities (> 100 g/cm{sup 3}). A detailed program called the National Ignition Campaign (NIC) has been developed to enable ignition experiments in 2010, with the goal of producing fusion ignition and burn of a deuterium-tritium (DT) fuel mixture in millimeter-scale target capsules. The first of the target experiments leading up to these ignition shots will begin in 2008. Targets for the National Ignition Campaign are both complex and precise, and are extraordinarily demanding in materials fabrication, machining, assembly, cryogenics and characterization. An overview of the campaign for ignition will be presented, along with technologies for target fabrication, assembly and metrology and advances in growth and x-ray imaging of DT ice layers. The sum of these efforts represents a quantum leap in target precision, characterization, manufacturing rate and flexibility over current state-of-the-art.
Date:
March 12, 2007
Creator:
Atherton, L J; Moses, E I; Carlisle, K & Kilkenny, J
Object Type:
Article
System:
The UNT Digital Library
Comparing the risk profiles of renewable and natural gas electricity contracts: A summary of the California Department of Water Resources contracts
Electricity markets in the United States have witnessed unprecedented instability over the last few years, with substantial volatility in wholesale market prices, significant financial distress among major industry organizations, and unprecedented legal, regulatory and legislative activity. These events demonstrate the considerable risks that exist in the electricity industry. Recent industry instability also illustrates the need for thoughtful resource planning to balance the cost, reliability, and risk of the electricity supplied to end-use customers. In balancing different supply options, utilities, regulators, and other resource planners must consider the unique risk profiles of each generating source. This paper evaluates the relative risk profiles of renewable and natural gas generating plants. The risks that exist in the electricity industry depend in part on the technologies that are used to generate electricity. Natural gas has become the fuel of choice for new power plant additions in the United States. To some, this emphasis on a single fuel source signals the potential for increased risk. Renewable generation sources, on the other hand, are frequently cited as a potent source of socially beneficial risk reduction relative to natural gas-fired generation. Renewable generation is not risk free, however, and also imposes certain costs on the electricity sector. …
Date:
March 12, 2003
Creator:
Bachrach, Devra; Wiser, Ryan; Bolinger, Mark & Golove, William
Object Type:
Report
System:
The UNT Digital Library
Environmental Tests of the Flight GLAST LAT Tracker Towers
The Gamma-ray Large Area Space telescope (GLAST) is a gamma-ray satellite scheduled for launch in 2008. Before the assembly of the Tracker subsystem of the Large Area Telescope (LAT) science instrument of GLAST, every component (tray) and module (tower) has been subjected to extensive ground testing required to ensure successful launch and on-orbit operation. This paper describes the sequence and results of the environmental tests performed on an engineering model and all the flight hardware of the GLAST LAT Tracker. Environmental tests include vibration testing, thermal cycles and thermal-vacuum cycles of every tray and tower as well as the verification of their electrical performance.
Date:
March 12, 2008
Creator:
Bagagli, R.; Baldini, L.; Bellazzini, R.; Barbiellini, G.; Belli, F.; Borden, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Automobile and Light Truck Fuel Economy: The CAFE Standards
One of the least controversial provisions of the Energy Policy and Conservation Act of 1975 (P.L. 94-163) established corporate average fuel economy (CAFE) standards for new passenger cars. This report presents a brief background and analysis regarding the price of crude oil that brought into sharp focus the fuel inefficiency of U.S. automobiles. The report also discusses the previous issues and the most recent developments regarding CAFE.
Date:
March 12, 2003
Creator:
Bamberger, Robert L.
Object Type:
Report
System:
The UNT Digital Library
Strategic Petroleum Reserve
None
Date:
March 12, 2003
Creator:
Bamberger, Robert L.
Object Type:
Report
System:
The UNT Digital Library
Exemptions from Environmental Law for the Department of Defense: Background and Issues for Congress
This report provides Background and Issues for Congress on Exemptions from Environmental Law for the Department of Defense. several environmental statutes contain national security exemptions which is a department of defense can obtain on a case by case basis.
Date:
March 12, 2007
Creator:
Bearden, David M.
Object Type:
Report
System:
The UNT Digital Library
The Tevatron collider run 2 Prospects for discoveries in particle physics
The chances of discovering the Standard Model Higgs boson in Run 2 at the Fermilab Tevatron Collider are discussed. The reach of a search for MSSM Higgs boson and for other Susy particles is also mentioned. The large integrated luminosity potentially offered by the upgraded Tevatron in the years before the start of LHC will make an exciting physics program possible in the next several years. Let aside the luminosity, we can rely now on two much more powerful detectors than in run 1. This is a very real point of strength of the run 2 Tevatron program. The progress of the Tevatron from spring this year has been slow but steady. From this, there is no reason for being pessimistic, but admittedly no particular reason for being optimistic as well. CDF will be able to produce physics quality data early in 2002. After that, data will flow for years and years. We expect to be able to publish the first papers based on the new data in fall 2002.
Date:
March 12, 2002
Creator:
Bellettini, Giorgio
Object Type:
Article
System:
The UNT Digital Library
The Rice Thresher, Vol. 91, No. 22, Ed. 1 Friday, March 12, 2004
A weekly student newspaper from the Rice University in Houston, Texas that includes campus news and commentaries along with advertising.
Date:
March 12, 2004
Creator:
Berenson, Mark
Object Type:
Newspaper
System:
The Portal to Texas History
The Two-Loop Six-Point MHV Amplitude in Maximally Supersymmetric Yang-Mills Theory
We give a representation of the parity-even part of the planar two-loop six-gluon MHV amplitude of N = 4 super-Yang-Mills theory, in terms of loop-momentum integrals with simple dual conformal properties. We evaluate the integrals numerically in order to test directly the ABDK/BDS all-loop ansatz for planar MHV amplitudes. We find that the ansatz requires an additive remainder function, in accord with previous indications from strong-coupling and Regge limits. The planar six-gluon amplitude can also be compared with the hexagonal Wilson loop computed by Drummond, Henn, Korchemsky and Sokatchev in arXiv:0803.1466 [hep-th]. After accounting for differing singularities and other constants independent of the kinematics, we find that the Wilson loop and MHV-amplitude remainders are identical, to within our numerical precision. This result provides non-trivial confirmation of a proposed n-point equivalence between Wilson loops and planar MHV amplitudes, and suggests that an additional mechanism besides dual conformal symmetry fixes their form at six points and beyond.
Date:
March 12, 2008
Creator:
Bern, Z.; Dixon, L.J.; Kosower, D.A.; Roiban, R.; Spradlin, M.; Vergu, C. et al.
Object Type:
Article
System:
The UNT Digital Library
A fluctuating environment as a source of periodic modulation
Article discussing a fluctuating environment as a source of periodic modulation.
Date:
March 12, 2007
Creator:
Bianco, Simone; Grigolini, Paolo & Paradisi, Paolo
Object Type:
Article
System:
The UNT Digital Library
Appropriations for FY2002: An Overview
Appropriations are one part of a complex federal budget process that includes budget resolutions, appropriations (regular, supplemental, and continuing) bills, rescissions, and budget reconciliation bills. This report is a guide to one of the 13 regular appropriations bills that Congress passes each year.
Date:
March 12, 2002
Creator:
Bley, Mary Frances
Object Type:
Report
System:
The UNT Digital Library
Global Climate Change: U.S. Greenhouse Gas Emissions - Status, Trends, and Projections
This report discusses greenhouse gas emissions and baselines in the U.S. and various aspects of future projections.
Date:
March 12, 2002
Creator:
Blodgett, John E. & Parker, Larry
Object Type:
Report
System:
The UNT Digital Library
Stark tuning of donor electron spins in silicon
We report Stark shift measurements for 121Sb donor electronspins in silicon using pulsed electron spin resonance. Interdigitatedmetal gates on top of a Sb-implanted 28Si epi-layer are used to applyelectric fields. Two Stark effects are resolved: a decrease of thehyperfine coupling between electron and nuclear spins of the donor and adecrease in electron Zeeman g-factor. The hyperfine term prevails atX-band magnetic fields of 0.35T, while the g-factor term is expected todominate at higher magnetic fields. A significant linear Stark effect isalso resolved presumably arising from strain.
Date:
March 12, 2006
Creator:
Bradbury, Forrest R.; Tyryshkin, Alexei M.; Sabouret, Guillaume; Bokor, Jeff; Schenkel, Thomas & Lyon, Stephen A.
Object Type:
Article
System:
The UNT Digital Library
Computational investigation of unusual behavior in certain capillary tubes
We investigate computationally two recent mathematical findings involving unusual behavior of solutions of the Young-Laplace capillary equation in cylindrical tubes of particular sections. The first concerns a configuration for which smoothing of the boundary curve at a sharp corner leads from existence to non-existence of a solution over the container section in zero gravity. The second describes a discontinuous behavior of relative rise height in nesting tubes placed vertically in an infinite reservoir. The numerical results support and quantify the mathematical predictions.
Date:
March 12, 2004
Creator:
Brady, Victor; Concus, Paul & Finn, Robert
Object Type:
Article
System:
The UNT Digital Library
The Goldthwaite Eagle (Goldthwaite, Tex.), Vol. 114, No. 36, Ed. 1 Wednesday, March 12, 2008
Weekly newspaper from Goldthwaite, Texas that includes local, state, and national news along with extensive advertising.
Date:
March 12, 2008
Creator:
Bridges, Steven W.
Object Type:
Newspaper
System:
The Portal to Texas History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 88, No. 130, Ed. 1 Wednesday, March 12, 2003
Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date:
March 12, 2003
Creator:
Broaddus, Matthew B.
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 89, No. 157, Ed. 1 Friday, March 12, 2004
Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date:
March 12, 2004
Creator:
Broaddus, Matthew B.
Object Type:
Newspaper
System:
The Gateway to Oklahoma History