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Multiple-code simulation study of the long-term EDZ evolution of geological nuclear waste repositories (open access)

Multiple-code simulation study of the long-term EDZ evolution of geological nuclear waste repositories

This simulation study shows how widely different model approaches can be adapted to model the evolution of the excavation disturbed zone (EDZ) around a heated nuclear waste emplacement drift in fractured rock. The study includes modeling of coupled thermal-hydrological-mechanical (THM) processes, with simplified consideration of chemical coupling in terms of time-dependent strength degradation or subcritical crack growth. The different model approaches applied in this study include boundary element, finite element, finite difference, particle mechanics, and elastoplastic cellular automata methods. The simulation results indicate that thermally induced differential stresses near the top of the emplacement drift may cause progressive failure and permeability changes during the first 100 years (i.e., after emplacement and drift closure). Moreover, the results indicate that time-dependent mechanical changes may play only a small role during the first 100 years of increasing temperature and thermal stress, whereas such time-dependency is insignificant after peak temperature, because decreasing thermal stress.
Date: October 23, 2008
Creator: Rutqvist, J.; Backstrom, A.; Chijimatsu, M.; Feng, X. T.; Pan, P. Z.; Hudson, J. et al.
System: The UNT Digital Library
Residual phase noise measurements of the input section in a receiver (open access)

Residual phase noise measurements of the input section in a receiver

If not designed properly, the input section of an analog down-converter can introduce phase noise that can prevail over other noise sources in the system. In the paper we present residual phase noise measurements of a simplified input section of a classical receiver that is composed of various commercially available mixers and driven by an LO amplifier.
Date: October 1, 2007
Creator: Mavric, Uros & Chase, Brian
System: The UNT Digital Library
Dielectric Wall Accelerator Technology (open access)

Dielectric Wall Accelerator Technology

The dielectric wall accelerator (DWA) is a compact pulsed power device where the pulse forming lines, switching, and vacuum wall are integrated into a single compact geometry. For this effort, we initiated a extensive compact pulsed power development program and have pursued the study of switching (gas, oil, laser induced surface flashover and photoconductive), dielectrics (ceramics and nanoparticle composites), pulse forming line topologies (asymmetric and symmetric Blumleins and zero integral pulse forming lines), and multilayered vacuum insulator (HGI) technology. Finally, we fabricated an accelerator cell for test on ETAII (a 5.5 MeV, 2 kA, 70 ns pulsewidth electron beam accelerator). We review our past results and report on the progress of accelerator cell testing.
Date: October 18, 2007
Creator: Sampayan, S.; Caporaso, G.; Chen, Y.; Harris, J.; Hawkins, S.; Holmes, C. et al.
System: The UNT Digital Library
Does complex absorption behavior leading to conditioning and damage in KDP/DKDP reflect the electronic structure of initiators? (open access)

Does complex absorption behavior leading to conditioning and damage in KDP/DKDP reflect the electronic structure of initiators?

Currently, most of our thinking about the defects responsible for initiating laser damage considers them as featureless absorbers. However, an increasing body of evidence, particularly involving multi-wavelength irradiation, suggests electronic structure of damage initiators is important in determining both initiation and conditioning behaviors in KDP. The effective absorption coefficient of energy under multi-wavelength irradiation cannot be accounted for by a structureless absorber, but is consistent with an initiator with a multi-level structure. We outline the evidence and assess the ability of such a simple multi-level model to explain these and other experimentally observed behaviors.
Date: October 24, 2007
Creator: Feit, M D; DeMange, P P; Negres, R A; Rubenchik, A M & Demos, S G
System: The UNT Digital Library
Lifetime Difference and CP Asymmetry in the Bs -> J/psi phi decay (open access)

Lifetime Difference and CP Asymmetry in the Bs -> J/psi phi decay

The B{sub s} meson is an interesting particle to study because a sizable mixing induced CP violation in the B{sub s} -- {bar B}{sub s} system would be an indication for physics beyond the Standard Model. In this paper we present a measurement of the lifetime difference {Delta}{Gamma} between the B{sub s} mass eigenstates and the CP violating phase in the decay B{sub s} {yields} J/{psi}{phi}. In 1.7 fb{sup -1} of data collected with the CDF II detector at the Tevatron p{bar p} collider we measure {Delta}{Gamma} = 0.076{sup +0.059}{sub -0.063} (stat.) {+-}0.006 (syst.) ps{sup -1}, well consistent with the Standard Model prediction, and a mean B{sub s} lifetime of c{sub tau}{sub s} = 456 {+-} 13 (stat.) {+-} (syst.) {micro}m. We find no evidence for CP violation.
Date: October 1, 2007
Creator: Kuhr, Thomas
System: The UNT Digital Library
The CMS dataset bookkeeping service (open access)

The CMS dataset bookkeeping service

The CMS Dataset Bookkeeping Service (DBS) has been developed to catalog all CMS event data from Monte Carlo and Detector sources. It provides the ability to identify MC or trigger source, track data provenance, construct datasets for analysis, and discover interesting data. CMS requires processing and analysis activities at various service levels and the DBS system provides support for localized processing or private analysis, as well as global access for CMS users at large. Catalog entries can be moved among the various service levels with a simple set of migration tools, thus forming a loose federation of databases. DBS is available to CMS users via a Python API, Command Line, and a Discovery web page interfaces. The system is built as a multi-tier web application with Java servlets running under Tomcat, with connections via JDBC to Oracle or MySQL database backends. Clients connect to the service through HTTP or HTTPS with authentication provided by GRID certificates and authorization through VOMS. DBS is an integral part of the overall CMS Data Management and Workflow Management systems.
Date: October 1, 2007
Creator: Afaq, Anzar,; /Fermilab; Dolgert, Andrew; /Cornell U., Phys. Dept.; Guo, Yuyi; /Fermilab et al.
System: The UNT Digital Library
The National Ignition Facility: The world's largest optical system (open access)

The National Ignition Facility: The world's largest optical system

None
Date: October 22, 2007
Creator: Stolz, C J
System: The UNT Digital Library
Effect of various errors on the Spin Tune and Stable Spin Axis (open access)

Effect of various errors on the Spin Tune and Stable Spin Axis

Even though RHIC has two full Siberian snakes in each ring, there are various perturbations to the ideal case including orbit errors at the snakes, experiment solenoids, injection bumps, and interlaced horizontal-vertical bumps at the hydrogen jet polarimeter. These errors can cause depolarization by shifting the spin tune and tilting the stable spin direction away from vertical. Tilting of the stable spin axis can enhance horizontal depolarizing resonances. This paper presents preliminary results for some of these error scenarios, as well as their impact on the stable spin directions at STAR and PHENIX.
Date: October 6, 2008
Creator: MacKay, W. W.
System: The UNT Digital Library
Visualization of Trajectories of Electron Beams Emitted by an IonSource with Closed Electron Drift (open access)

Visualization of Trajectories of Electron Beams Emitted by an IonSource with Closed Electron Drift

Trajectories of electron beams emitted by an ion source with an anode layer and Hall electron closed drift orbits were visualized using light emission from a working gas excited by electrons. Gas discharge of magnetron type, arising in the beam drift region under the influence of an electric field of a target bias potential, was visualized.
Date: October 1, 2007
Creator: Institue of Physics, National Academy of Sciences of Ukraine; Brown, Ian G.; Bordenjuk, Ian V.; Panchenko, Oleg A.; Sologub, Sergei V. & Brown, Ian G.
System: The UNT Digital Library
ACCURACY OF CO2 SENSORS (open access)

ACCURACY OF CO2 SENSORS

Are the carbon dioxide (CO2) sensors in your demand controlled ventilation systems sufficiently accurate? The data from these sensors are used to automatically modulate minimum rates of outdoor air ventilation. The goal is to keep ventilation rates at or above design requirements while adjusting the ventilation rate with changes in occupancy in order to save energy. Studies of energy savings from demand controlled ventilation and of the relationship of indoor CO2 concentrations with health and work performance provide a strong rationale for use of indoor CO2 data to control minimum ventilation rates1-7. However, this strategy will only be effective if, in practice, the CO2 sensors have a reasonable accuracy. The objective of this study was; therefore, to determine if CO2 sensor performance, in practice, is generally acceptable or problematic. This article provides a summary of study methods and findings ? additional details are available in a paper in the proceedings of the ASHRAE IAQ?2007 Conference8.
Date: October 1, 2008
Creator: Fisk, William J.; Faulkner, David & Sullivan, Douglas P.
System: The UNT Digital Library
Charmless Two-Body and Quasi-Two-Body B-decays at BABAR (open access)

Charmless Two-Body and Quasi-Two-Body B-decays at BABAR

The authors present improved measurements of the branching fractions and CP asymmetries in the two-body decays B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, B{sup 0} {yields} K{sup 0}{pi}{sup 0} and B{sup 0} {yields} K{sup +}{pi}{sup -} as well as the quasi two-body B{sup 0} {yields} K{sub 1}(1270){sup +} {pi}{sup -} and B{sup 0} {yields} K{sub 1}(1400){sup +} {pi}{sup -} decays. These updated measurements are made using the complete set of BABAR data taken at the Y(4S) resonance, collected between 1999 and 2007 at the PEP-II collider at SLAC.
Date: October 13, 2008
Creator: Ofte, Ingrid
System: The UNT Digital Library
Measurement of tritium permeation in flibe (2LiF•BeF2) (open access)

Measurement of tritium permeation in flibe (2LiF•BeF2)

This paper reports on the experimental investigation of tritium permeation in flibe (2LiF-BeF2) at the Safety and Tritium Applied Research facility of the Idaho National Laboratory. A stainless steel cell formed by two independent volumes separated by a 2mm thick nickel membrane is maintained at temperatures between 500 and 700 degrees Celsius. A controlled amount of T2 gas is flown in excess of argon in the source volume in contact with the bottom side of the nickel membrane, while a layer of molten salt is in contact with the top side. The tritium permeating above the liquid surface is carried by an argon flow to a diagnostic system comprised of a quadrupole mass spectrometer, a gas chromatographer and a proportional counter. Tritium permeability in flibe as a function of temperature is determined by the measured permeation flow rates reached in steady-state conditions, while the diffusivity is determined by fitting the transient process with the analytical solution for the diffusion process. As a result, the solubility of tritium in flibe as a function of temperature is also determined.
Date: October 1, 2007
Creator: Calderoni, P.; Sharpe, P.; Hara, M. & Oya, Y.
System: The UNT Digital Library
Design and Implementation of an Open, Interoperable AutomatedDemand Response Infrastructure (open access)

Design and Implementation of an Open, Interoperable AutomatedDemand Response Infrastructure

This paper describes the concept for and lessons from the development and field-testing of an open, interoperable communications infrastructure to support automating demand response (DR). Automating DR allows greater levels of participation and improved reliability and repeatability of the demand response and customer facilities. Automated DR systems have been deployed for critical peak pricing and demand bidding and are being designed for real time pricing. The system is designed to generate, manage, and track DR signals between utilities and Independent System Operators (ISOs) to aggregators and end-use customers and their control systems.
Date: October 1, 2007
Creator: Piette, Mary Ann; Kiliccote, Sila & Ghatikar, Girish
System: The UNT Digital Library
Dust mobilization and transport modeling for loss of vacuum accidents (open access)

Dust mobilization and transport modeling for loss of vacuum accidents

We develop a general continuum fluid dynamic model for dust transport in loss of vacuum accidents in fusion energy systems. The relationship between this general approach and established particle transport methods is clarified, in particular the relationship between the seemingly disparate treatments of aerosol dynamics and Lagrangian particle tracking. Constitutive equations for granular flow are found to be inadequate for prediction of mobilization, as these models essentially impose a condition of flow from the outset. Experiments confirm that at low shear, settled dust piles behave more like a continuum solid, and suitable solid models will be required to predict the onset of dust mobilization.
Date: October 1, 2007
Creator: Humrickhouse, P.W. & Sharpe, J.P.
System: The UNT Digital Library
Comparison between S/1 and R/1 tests and damage density vs. fluence (rho(phi)) results for unconditioned and sub-nanosecond laser-conditioned KD2PO4 crystals (open access)

Comparison between S/1 and R/1 tests and damage density vs. fluence (rho(phi)) results for unconditioned and sub-nanosecond laser-conditioned KD2PO4 crystals

We present S/1 and R/1 test results on unconditioned and 355 nm (3{omega}), 500 ps laser conditioned DKDP. We find up to {approx}2.5X improvement in fluence in the S/1 performance after 3{omega}, 500 ps conditioning to 5 J/cm{sup 2}. For the first time, we observe a shift to higher fluences in the R/1 results for DKDP at 3{omega}, 7 ns due to 500 ps laser conditioning. The S/1 results are compared to {rho}({phi}) results previously measured on the same DKDP crystal [1]. A consistent behavior in fluence was found between the S/1 and {rho}({phi}) results for unconditioned and 500 ps conditioned DKDP. We were successful at using Poisson statistics to derive a connection between the S/1 and {rho}({phi}) results that could be tested with our data sets by trying to predict the shape of the {rho}({phi}) curve. The value for the power dependence on fluence of {rho}({phi}) derived from the S/1 data was {approx}11 {+-} 50%. The results presented and discussed here imply a strong correlation between the damage probability (S/1) test and {rho}({phi}). We find a consistent description of the two test types in terms of a power law {rho}({phi}) and that this basic shape held for all cases, …
Date: October 31, 2007
Creator: Adams, J. J.; Jarboe, J.; Feit, M. & Hackel, R.
System: The UNT Digital Library
Development of a Fan-Filter Unit Test Standard, Laboratory Validations, and its Applications across Industries (open access)

Development of a Fan-Filter Unit Test Standard, Laboratory Validations, and its Applications across Industries

Lawrence Berkeley National Laboratory (LBNL) is now finalizing the Phase 2 Research and Demonstration Project on characterizing 2-foot x 4-foot (61-cm x 122-cm) fan-filter units in the market using the first-ever standard laboratory test method developed at LBNL.[1][2][3] Fan-filter units deliver re-circulated air and provide particle filtration control for clean environments. Much of the energy in cleanrooms (and minienvironments) is consumed by 2-foot x 4-foot (61-cm x 122-cm) or 4-foot x 4-foot (122-cm x 122-cm) fan-filter units that are typically located in the ceiling (25-100% coverage) of cleanroom controlled environments. Thanks to funding support by the California Energy Commission's Industrial Program of the Public Interest Energy Research (PIER) Program, and significant participation from manufacturers and users of fan-filter units from around the world, LBNL has developed and performed a series of standard laboratory tests and reporting on a variety of 2-foot x 4-foot (61-cm x 122-cm) fan-filter units (FFUs). Standard laboratory testing reports have been completed and reported back to anonymous individual participants in this project. To date, such reports on standard testing of FFU performance have provided rigorous and useful data for suppliers and end users to better understand, and more importantly, to quantitatively characterize performance of FFU products …
Date: October 20, 2006
Creator: Xu, Tengfang
System: The UNT Digital Library
Air, Thermal and Water Management for PEM Fuel Cell Systems (open access)

Air, Thermal and Water Management for PEM Fuel Cell Systems

This report has a detailed study of the fuel cells.
Date: October 1, 2008
Creator: Mirza, Mark K. Gee Zia
System: The UNT Digital Library
Search for Standard Model Higgs Bosons Produced in Association with W Bosons (open access)

Search for Standard Model Higgs Bosons Produced in Association with W Bosons

The authors report on the results of a search for standard model Higgs bosons produced in association with W bosons from p{bar p} collisions at {radical}s = 1.96 TeV. The search uses a data sample corresponding to approximately 1 fb{sup -1} of integrated luminosity. Events consistent with the W {yields} {ell}{nu} and H {yields} b{bar b} signature are selected by triggering on a high-p{sub T} electron or muon candidate and tagging one or two of the jet candidates as having originated from b quarks. A neural network filter rejects a fraction of tagged charm and light flavor jets, increasing the b-jet purity in the sample and thereby reducing the background to Higgs boson production. They observe no excess {ell}{nu}b{bar b} production beyond the background expectation, and they set 95% confidence level upper limits on the production cross section times branching fraction {sigma}(p{bar p} {yields} WH) {center_dot} Br(H {yields} b{bar b}) ranging from 3.9 to 1.3 pb, for specific Higgs boson mass hypotheses in the range 110 to 150 GeV/c{sup 2}, respectively.
Date: October 1, 2007
Creator: Aaltonen, T.
System: The UNT Digital Library
Introduction to Electroweak Symmetry Breaking (open access)

Introduction to Electroweak Symmetry Breaking

The Standard Model (SM) is the backbone of elementary particle physics-not only does it provide a consistent framework for studying the interactions of quark and leptons, but it also gives predictions which have been extensively tested experimentally. In these notes, I review the electroweak sector of the Standard Model, discuss the calculation of electroweak radiative corrections to observables, and summarize the status of SM Higgs boson searches. Despite the impressive experimental successes, however, the electroweak theory is not completely satisfactory and the mechanism of electroweak symmetry breaking is untested. I will discuss the logic behind the oft-repeated statement: 'There must be new physics at the TeV scale'. These lectures reflect my strongly held belief that upcoming results from the LHC will fundamentally change our understanding of electroweak symmetry breaking. In these lectures, I review the status of the electroweak sector of the Standard Model, with an emphasis on the importance of radiative corrections and searches for the Standard Model Higgs boson. A discussion of the special role of the TeV energy scale in electroweak physics is included.
Date: October 2, 2008
Creator: Dawson,S.
System: The UNT Digital Library
A Local Corrections Algorithm for Solving Poisson's Equation inThree Dimensions (open access)

A Local Corrections Algorithm for Solving Poisson's Equation inThree Dimensions

We present a second-order accurate algorithm for solving thefree-space Poisson's equation on a locally-refined nested grid hierarchyin three dimensions. Our approach is based on linear superposition oflocal convolutions of localized charge distributions, with the nonlocalcoupling represented on coarser grids. There presentation of the nonlocalcoupling on the local solutions is based on Anderson's Method of LocalCorrections and does not require iteration between different resolutions.A distributed-memory parallel implementation of this method is observedto have a computational cost per grid point less than three times that ofa standard FFT-based method on a uniform grid of the same resolution, andscales well up to 1024 processors.
Date: October 30, 2006
Creator: McCorquodale, Peter; Colella, Phillip; Balls, Gregory T. & Baden,Scott B.
System: The UNT Digital Library
Overview of Offshore Wind Technology: Preprint (open access)

Overview of Offshore Wind Technology: Preprint

This paper provides a short overview of some of the challenges facing the growth of offshore wind energy technology.
Date: October 1, 2007
Creator: Butterfield, C. P.; Musial, W. & Jonkman, J.
System: The UNT Digital Library
High-Level Control System in C#* (open access)

High-Level Control System in C#*

We have started upgrading the control room programs for the injector at the Advanced Light Source (ALS). We chose to program in C* exclusively on the .NET Framework to create EPICS client programs on Windows Vista PCs. This paper reports the status of this upgrade project.
Date: October 14, 2008
Creator: Nishimura, Hiroshi; Timossi, Chris; Portmann, Greg; Urashka, Michael.; Ikami, Craig & Beaudrow, M.
System: The UNT Digital Library
CP Violation in Hadronic Penguins at BABAR (open access)

CP Violation in Hadronic Penguins at BABAR

The authors present preliminary measurements of time-dependent CP-violation parameters in the decay B{sup 0} {yields} {omega}K{sub S}{sup 0}, B{sup 0} {yields} {eta}{prime}K{sup 0}, B{sup 0} {yields} {pi}{sup 0}K{sub S}{sup 0}, B{sup 0} {yields} {phi}K{sub S}{sup 0}{pi}{sup 0}, and B{sup 0} {yields} K{sup +}K{sup -}K{sub S}{sup 0}, which includes the resonant final states {phi}K{sub S}{sup 0} and f{sub 0}(980)K{sub S}{sup 0}. The data sample corresponds to the full BABAR dataset of 467 x 10{sup 6} B{bar B} pairs produced at the PEP-II asymmetric-energy E{sup +}e{sup -} collider at the Stanford Linear Accelerator Center.
Date: October 30, 2008
Creator: Hirschauer, J. & Collaboration, for the BABAR
System: The UNT Digital Library
Potential of Photovoltaics: Preprint (open access)

Potential of Photovoltaics: Preprint

This paper discusses PV in the world energy portfolio, PV basics, PV technologies, and vacuum web-coating applications in PV.
Date: October 1, 2008
Creator: Nelson, B. P.
System: The UNT Digital Library