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Strong-strong beam-beam simulation on parallel computer
The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.
Date:
August 2, 2004
Creator:
Qiang, Ji
Object Type:
Article
System:
The UNT Digital Library
Pump Side-scattering in Ultra-powerful Backward Raman Amplifiers
Extremely large laser power might be obtained by compressing laser pulses through backward Raman amplification (BRA) in plasmas. Premature Raman backscattering of a laser pump by plasma noise might be suppressed by an appropriate detuning of the Raman resonance, even as the desired amplification of the seed persists with a high efficiency. In this paper, we analyze side-scattering of laser pumps by plasma noise in backward Raman amplifiers. Though its growth rate is smaller than that of backscattering, the side-scattering can nevertheless be dangerous, because of a longer path of side-scattered pulses in plasmas and because of an angular dependence of the Raman resonance detuning. We show that side-scattering of laser pumps by plasma noise in BRA might be suppressed to a tolerable level at all angles by an appropriate combination of two detuning mechanisms associated with plasma density gradient and pump chirp.
Date:
March 2, 2004
Creator:
A.A. Solodov, V.M. Malkin, and N.J. Fisch
Object Type:
Report
System:
The UNT Digital Library
Scaled Opposite Spin Second Order Moller-Plesset Correlation Energy: An Economical Electronic Structure Method
A simplified approach to treating the electron correlation energy is suggested in which only the alpha-beta component of the second order Moller-Plesset energy is evaluated, and then scaled by an empirical factor which is suggested to be 1.3. This scaled opposite spin second order energy (SOS-MP2) yields results for relative energies and derivative properties that are statistically improved over the conventional MP2 method. Furthermore, the SOS-MP2 energy can be evaluated without the 5th order computational steps associated with MP2 theory, even without exploiting any spatial locality. A 4th order algorithm is given for evaluating the opposite spin MP2 energy using auxiliary basis expansions, and a Laplace approach, and timing comparisons are given.
Date:
August 2, 2004
Creator:
Jung, Yousung; Lochan, Rohini C.; Dutoi, Anthony D. & Head-Gordon, Martin
Object Type:
Article
System:
The UNT Digital Library
Evaluation of the Emission, Transport, and Deposition of Mercury, Fine Particulate Matter, and Arsenic From Coal-Based Power Plants in the Ohio River Valley Region Progress Report
Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NOx, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg{sup 0} and RGM. Approximately of 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal …
Date:
October 2, 2004
Creator:
Crist, Kevin
Object Type:
Report
System:
The UNT Digital Library
Energy efficiency standards for residential and commercial equipment: Additional opportunities
Energy efficiency standards set minimum levels of energy efficiency that must be met by new products. Depending on the dynamics of the market and the level of the standard, the effect on the market for a given product may be small, moderate, or large. Energy efficiency standards address a number of market failures that exist in the buildings sector. Decisions about efficiency levels often are made by people who will not be responsible for the energy bill, such as landlords or developers of commercial buildings. Many buildings are occupied for their entire lives by very temporary owners or renters, each unwilling to make long-term investments that would mostly reward subsequent users. And sometimes what looks like apathy about efficiency merely reflects inadequate information or time invested to evaluate it. In addition to these sector-specific market failures, energy efficiency standards address the endemic failure of energy prices to incorporate externalities. In the U.S., energy efficiency standards for consumer products were first implemented in California in 1977. National standards became effective starting in 1988. By the end of 2001, national standards were in effect for over a dozen residential appliances, as well as for a number of commercial sector products. Updated standards …
Date:
August 2, 2004
Creator:
Rosenquist, Greg; McNeil, Michael; Iyer, Maithili; Meyers, Steve & McMahon, Jim
Object Type:
Report
System:
The UNT Digital Library
Angle-Resolved 2D Imaging of Electron Emission Processes in Atoms and Molecules
A variety of electron emission processes have been studied in detail for both atomic and molecular systems, using a highly efficient experimental system comprising two time-of-flight (TOF) rotatable electron energy analyzers and a 3rd generation synchrotron light source. Two examples are used here to illustrate the obtained results. Firstly, electron emissions in the HCL molecule have been mapped over a 14 eV wide photon energy range over the Cl 2p ionization threshold. Particular attention is paid to the dissociative core-excited states, for which the Auger electron emission shows photon energy dependent features. Also, the evolution of resonant Auger to the normal Auger decay distorted by post-collision interaction has been observed and the resonating behavior of the valence photoelectron lines studied. Secondly, an atomic system, neon, in which excitation of doubly excited states and their subsequent decay to various accessible ionic states has been studied. Since these processes only occurs via inter-electron correlations, the many body dynamics of an atom can be probed, revealing relativistic effects, surprising in such a light atom. Angular distribution of the decay of the resonances to the parity unfavored continuum exhibits significant deviation from the LS coupling predictions.
Date:
September 2, 2004
Creator:
Kukk, E.; Wills, A. A.; Langer, B.; Bozek, J. D. & Berrah, N.
Object Type:
Article
System:
The UNT Digital Library
National facility for advanced computational science: A sustainable path to scientific discovery
Lawrence Berkeley National Laboratory (Berkeley Lab) proposes to create a National Facility for Advanced Computational Science (NFACS) and to establish a new partnership between the American computer industry and a national consortium of laboratories, universities, and computing facilities. NFACS will provide leadership-class scientific computing capability to scientists and engineers nationwide, independent of their institutional affiliation or source of funding. This partnership will bring into existence a new class of computational capability in the United States that is optimal for science and will create a sustainable path towards petaflops performance.
Date:
April 2, 2004
Creator:
Simon, Horst; Kramer, William; Saphir, William; Shalf, John; Bailey, David; Oliker, Leonid et al.
Object Type:
Report
System:
The UNT Digital Library
Materials Research Collaborative Access Team Final Report - DOE Grant No.DEFG0200ER45811
Operations Funding for the Materials Research Collaborative Access Team. In the proposal they presented five specific objectives for the MR-CAT Insertion Device beam line: (1) enable the accomplishment of the best possible science at MR-CAT; (2) facilitate efficient set-up and operations of a variety of complex materials-related experiments; (3) open the beamlines' facilities to scientists and science projects from non-traditional backgrounds and disciplines, respectively; (4) enable efficient 24 hour use of the beamline through interdisciplinary research teams and appropriate operations support; and (5) develop selected operations modes in support of the MR-CAT institutions, DOE collaborators, and general users.
Date:
May 2, 2004
Creator:
Segre, Carlo
Object Type:
Report
System:
The UNT Digital Library
Study of the beam-beam limit in e{sup +}e{sup -} circular colliders
Beam-beam effects limit the luminosity of circular colliders. Once the bunch population exceeds a threshold, the luminosity increases at a slower rate. This phenomenon is called the beam-beam limit. Onset of the beam-beam limit has been analyzed with various simulation methods based on the weak-strong and strong-strong models. We have observed that an incoherent phenomenon is mainly concerned in the beam-beam limit. The simulation have shown that equilibrium distributions of the two colliding beams are distorted from Gaussians when the luminosity is limited. The beam-beam limit is estimated to be (xi) {approx} 0.1 for a B factory with damping time of several thousand turns.
Date:
April 2, 2004
Creator:
Ohmi, K.; Tawada, M.; Cai, Y.; Kamada, S.; Oide, K. & Qiang, J.
Object Type:
Article
System:
The UNT Digital Library
PKI-based security for peer-to-peer information sharing
The free flow of information is the feature that has made peer-to-peer information sharing applications popular. However, this very feature holds back the acceptance of these applications by the corporate and scientific communities. In these communities it is important to provide confidentiality and integrity of communication and to enforce access control to shared resources. We present a number of security mechanisms that can be used to satisfy these security requirements. Our solutions are based on established and proven security techniques and we utilize existing technologies when possible. As a proof of concept, we have developed an information sharing system, called scishare, which integrates a number of these security mechanisms to provide a secure environment for information sharing. This system will allow a broader set of user communities to benefit from peer-to-peer information sharing.
Date:
May 2, 2004
Creator:
Berket, Karlo; Essiari, Abdelilah & Muratas, Artur
Object Type:
Article
System:
The UNT Digital Library
Exploring little Higgs models with ATLAS at the LHC
We discuss possible searches for the new particles predicted by Little Higgs Models at the LHC. By using a simulation of the ATLAS detector, we demonstrate how the predicted quark, gauge bosons and additional Higgs bosons can be found and estimate the mass range over which their properties can be constrained.
Date:
February 2, 2004
Creator:
Azuelos, G.; Benslama, K.; Costanzo, D.; Couture, G.; Garcia, J.E.; Hinchliffe, I.G. et al.
Object Type:
Article
System:
The UNT Digital Library
Applying Simple Technology Accomplishes Visual Inspection Challenges
This paper discusses the successful implementation of simple video technologies at the Savannah River Site (SRS) to perform complex visual inspection, monitoring, and surveillance tasks. The constraints and challenges associated with remote viewing are discussed, and examples of applications are given. Work at SRS involves many radioactive, hazardous, and remote operations and activities, which require monitoring or surveillance. As well, many facilities, including tanks, cells, and pipelines, require inspections but are inaccessible to humans. SRTC supports SRS in these situations by applying simple remote viewing technologies to address these issues and accomplish monitoring and inspection goals.
Date:
April 2, 2004
Creator:
ROBINSON, CASANDRA
Object Type:
Report
System:
The UNT Digital Library
Conceptual Models of Flow through a Heterogeneous, Layered Vadose Zone under a Percolation Pond
Understanding how water and solutes move through the vadose zone is necessary to make effective remedial action decisions where contaminants were spilled or leaked at the ground surface or were buried in shallow land-disposal sites. In layered, heterogeneous systems, high contrasts in hydraulic conductivity can lead to formation of perched water zones, and enhanced lateral spread of contamination. Two conceptual models are considered solute for migration through the vadose zone. In the diffuse flow conceptual model, perched water zones accumulate until the head over the perching layer becomes sufficient to drive the infiltration through the perching layer. In the preferential flow conceptual model, perched water moves laterally until a path around the perching layer is encountered. Preferential flow paths can enhance contaminant migration because greater moisture saturation leads to higher advective velocities, and the preferential flow paths bypass low permeability layers with higher sorption capacity. Monitoring wells and instrumented boreholes were installed around a newly constructed industrial-waste percolation pond and an ephemeral river that lie over a 150-m-thick layered vadose zone. Background data gathered before discharge to the pond began show the presence of at least one, and possibly two, deep perched zones. The shallower zone, at approximately 45-m below …
Date:
February 2, 2004
Creator:
Baker, Kristine; Hull, Larry; Bennett, Jesse; Ansley, Shannon & Heath, Gail
Object Type:
Report
System:
The UNT Digital Library
New high performance hybrid magnet plates for DNA separation andbio-technology applications
A new class of magnet plates for biological and industrial applications has recently been developed at the D.O.E. Joint Genome Institute and Lawrence Berkeley National Laboratory (JGI/LBNL). These devices utilize hybrid technology that combines linear permanent magnet material and ferromagnetic material to produce significantly higher fields and gradients than currently available commercial magnet plates. These hybrid structures incorporate ferromagnetic poles that can be easily shaped to produce complex field distributions for specialized applications. The higher maximum fields and strong gradients of the hybrid structures result in greater holding forces on magnetized targets that are being processed as well as faster draw-down. Current development versions of these magnet plates have exhibited maximum fields in excess of 9000.0 Gauss. The design of these structures is easily scalable to allow for field increases to significantly above 1.0 tesla (10000.0gauss). Author's note: 11000.0 Gauss peak fields have been achieved as of January 2005.
Date:
August 2, 2004
Creator:
Humphries, David; Pollard, Martin; Elkin, Chris; Petermann, Karl; Reiter, Charles & Cepeda, Mario
Object Type:
Report
System:
The UNT Digital Library
Transport of Ions Across the Inner Envelope Membrane of Chloroplasts
The technical report outlines the results of nine years of research on how ions cross the inner envelope membrane of chloroplasts. The ions include protons, nitrite, calcium and ferrous iron. Bicarbonate transport was also studied.
Date:
June 2, 2004
Creator:
McCarty, R. E.
Object Type:
Report
System:
The UNT Digital Library
A performance evaluation of the Cray X1 for scientific applications
The last decade has witnessed a rapid proliferation of superscalar cache-based microprocessors to build high-end capability and capacity computers primarily because of their generality, scalability, and cost effectiveness. However, the recent development of massively parallel vector systems is having a significant effect on the supercomputing landscape. In this paper, we compare the performance of the recently-released Cray X1 vector system with that of the cacheless NEC SX-6 vector machine, and the superscalar cache-based IBM Power3 and Power4 architectures for scientific applications. Overall results demonstrate that the X1 is quite promising, but performance improvements are expected as the hardware, systems software, and numerical libraries mature. Code reengineering to effectively utilize the complex architecture may also lead to significant efficiency enhancements.
Date:
May 2, 2004
Creator:
Oliker, Leonid; Biswas, Rupak; Borrill, Julian; Canning, Andrew; Carter, Jonathan; Djomehri, Jahed et al.
Object Type:
Article
System:
The UNT Digital Library
Compatibility of Alternative Chlorinated Solvent Source Treatment Strategies With Monitored Natural Attenuation
One of the most powerful and promising strategies for optimizing environmental restoration is the use of combinations of technologies rather than a single technology to reach the target cleanup goals. The U. S. Department of Energy (DOE) is actively working to clean up legacy contamination from its operations. Notably, DOE is responsible for the cleanup of many sites where the contamination includes chlorinated solvents (or chlorinated volatile organic contaminants (CVOCs)). At some sites, groundwater plumes containing CVOCs tend to become relatively large. Estimates for times to remediate sites often ranges up to 100s of years for these large plumes. As a result, the CVOC plumes are a concern to DOE, regulators and stakeholders. In response to this challenge, DOE initiated a project to ''provide the technical and policy support to facilitate implementing appropriate passive cleanup... leading to responsible completion of active remediation activities at high risk DOE waste sites.'' A combined approach benefits from the ability to match the invasiveness and aggressiveness of the remedial action to the amount of contamination and level of risk. This matching process is particularly important for recalcitrant contaminants such as chlorinated solvents. Highly contaminated areas justify more intense remediation action(s) while minimally contaminated areas …
Date:
April 2, 2004
Creator:
LOONEY, BRIANB.
Object Type:
Report
System:
The UNT Digital Library
A Self-Consistent Approach for Calculating the Effective Hydraulic Conductivity of a Bimodal, Heterogeneous Medium
In this paper, we consider an approach for estimating the effective hydraulic conductivity of a 3D medium with a binary distribution of local hydraulic conductivities. The medium heterogeneity is represented by a combination of matrix medium conductivity with spatially distributed sets of inclusions. Estimation of effective conductivity is based on a self-consistent approach introduced by Shvidler (1985). The tensor of effective hydraulic conductivity is calculated numerically by using a simple system of equations for the main diagonal elements. Verification of the method is done by comparison with theoretical results for special cases and numerical results of Desbarats (1987) and our own numerical modeling. The method was applied to estimating the effective hydraulic conductivity of a 2D and 3D fractured porous medium. The medium heterogeneity is represented by a combination of matrix conductivity and a spatially distributed set of highly conductive fractures. The tensor of effective hydraulic conductivity is calculated for parallel- and random-oriented sets of fractures. The obtained effective conductivity values coincide with Romm's (1966) and Snow's (1969) theories for infinite fracture length. These values are also physically acceptable for the sparsely-fractured-medium case with low fracture spatial density and finite fracture length. Verification of the effective hydraulic conductivity obtained for …
Date:
January 2, 2004
Creator:
Pozdniakov, Sergey & Tsang, Chin-Fu
Object Type:
Article
System:
The UNT Digital Library
Cesium Ion Exchange Program at the Hanford River Protection Project Waste Treatment Plant
The River Protection Project - Hanford Tank Waste Treatment and Immobilization Plant will use cesium ion exchange to remove 137Cs from Low Activity Waste down to 0.3 Ci/m3 in the Immobilized LAW, ILAW product. The project baseline for cesium ion exchange is the elutable SuperLig, R, 644, SL-644, resin registered trademark of IBC Advanced Technologies, Inc., American Fork, UT or the Department of Energy approved equivalent. SL-644 is solely available through IBC Advanced Technologies. To provide an alternative to this sole-source resin supply, the RPP-WTP initiated a three-stage process for selection and qualification of an alternative ion exchange resin for cesium removal in the RPPWTP. It was recommended that resorcinol formaldehyde RF be pursued as a potential alternative to SL-644.
Date:
December 2, 2004
Creator:
CHARLES, NASH
Object Type:
Article
System:
The UNT Digital Library
High Energy Physics semiannual report of research activities. July 1, 2003 - December 31, 2003.
This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of July 1 through December 31, 2003. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of Division publications and colloquia are included.
Date:
June 2, 2004
Creator:
Spinka, H. M.; Nodulman, L. J.; Goodman, M. C.; Repond, J.; Ayres, D. S.; Proudfoot, J. et al.
Object Type:
Report
System:
The UNT Digital Library
Evaluation of the Emission, Transport, and Deposition of Mercury, Fine Particulate Matter, and Arsenic From Coal-Based Power Plants in the Ohio River Valley Region Progress Report
Ohio University, in collaboration with CONSOL Energy, Advanced Technology Systems, Inc. (ATS) and Atmospheric and Environmental Research, Inc. (AER) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation will involve two interrelated areas of effort: ambient air monitoring and regional-scale modeling analysis. The scope of work for the ambient air monitoring will include the deployment of a surface air monitoring (SAM) station in southeastern Ohio. The SAM station will contain sampling equipment to collect and measure mercury (including speciated forms of mercury and wet and dry deposited mercury), arsenic, particulate matter (PM) mass, PM composition, and gaseous criteria pollutants (CO, NOx, SO{sub 2}, O{sub 3}, etc.). Laboratory analysis of time-integrated samples will be used to obtain chemical speciation of ambient PM composition and mercury in precipitation. Near-real-time measurements will be used to measure the ambient concentrations of PM mass and all gaseous species including Hg{sup 0} and RGM. Approximately 18 months of field data will be collected at the SAM site to validate the proposed regional model simulations for episodic and seasonal model …
Date:
April 2, 2004
Creator:
Crist, Kevin
Object Type:
Report
System:
The UNT Digital Library
Electroweak results from CDF
Inclusive W and Z production cross-sections have been measured by CDF and certain electroweak parameters extracted with high precision from these measurements. New results on diboson production at the Tevatron are also presented.
Date:
June 2, 2004
Creator:
Waters, D. S.
Object Type:
Article
System:
The UNT Digital Library
Sludge Batch 3 Qualification in the SRTC Shielded Cells
The Defense Waste Processing Facility (DWPF) requested that a radioactive demonstration of the next batch of sludge slurry (Sludge Batch 3) be completed in the Shielded Cells Facility of the Savannah River Technology Center (SRTC). Sludge Batch 3 (SB3) consists of the heel in Tank 51, which included Plutonium (Pu) and Americium/Curium (Am/Cm); sludge slurry from Tank 7 (including sludge transferred into Tank 7 from Tanks 18 and 19); additional Pu transferred from H Canyon; a Neptunium (Np) transfer also from H Canyon; and the remaining Sludge Batch 2 material in Tank 40. Because the current contents of Tank 40 (Sludge Batch 2) have already been qualified, this qualification work did not include the contribution of Tank 40. Documented in this report are: preparation of a SB3 slurry using a Tank 51 sample from June 2003; a demonstration of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle using SB3 slurry; a demonstration of the DWPF Slurry Mix Evaporator (SME) cycle using SRAT product; glass fabrication and subsequent chemical durability evaluation using SB3 material; and evaluation of adding formic acid to the SME cycle product.
Date:
August 2, 2004
Creator:
PAREIZS, JOHNM.
Object Type:
Report
System:
The UNT Digital Library
Tank 5 Model for Sludge Removal Analysis
Computational fluid dynamics methods have been used to develop and provide slurry pump operational guidance for sludge heel removal in Tank 5. Flow patterns calculated by the model were used to evaluate the performance of various combinations of operating pumps and their orientation under steady-state indexed and transient oscillation modes. A model used for previous analyses has been updated to add the valve housing distribution piping and pipe clusters of the cooling coil supply system near pump no. 8 to the previous tank Type-I model. In addition, the updated model included twelve concrete support columns. This model would provide a more accurate assessment of sludge removal capabilities. The model focused on removal of the sludge heel located near the wall of Tank 5 using the two new slurry pumps. The models and calculations were based on prototypic tank geometry and expected normal operating conditions as defined by Tank Closure Project Engineering. Computational fluid dynamics models of Tank 5 with different operating conditions were developed using the FLUENT (trademark) code. The modeling results were used to assess the efficiency of sludge suspension and removal operations in the 75-ft tank. The models employed a three-dimensional approach, a two-equation turbulence model, and an …
Date:
September 2, 2004
Creator:
LEE, SI
Object Type:
Report
System:
The UNT Digital Library