Analysis of the Effect of Geometry Generated Turbulence on HCCI Combustion by Multi-Zone Modeling (open access)

Analysis of the Effect of Geometry Generated Turbulence on HCCI Combustion by Multi-Zone Modeling

This paper illustrates the applicability of a sequential fluid mechanics, multi-zone chemical kinetics model to analyze HCCI experimental data for two combustion chamber geometries with different levels of turbulence: a low turbulence disc geometry (flat top piston), and a high turbulence square geometry (piston with a square bowl). The model uses a fluid mechanics code to determine temperature histories in the engine as a function of crank angle. These temperature histories are then fed into a chemical kinetic solver, which determines combustion characteristics for a relatively small number of zones (40). The model makes the assumption that there is no direct linking between turbulence and combustion. The results show that the multi-zone model yields good results for both the disc and the square geometries. The model makes good predictions of pressure traces and heat release rates. The experimental results indicate that the high turbulence square geometry has longer burn duration than the low turbulence disc geometry. This difference can be explained by the sequential multi-zone model, which indicates that the cylinder with the square bowl has a thicker boundary layer that results in a broader temperature distribution. This broader temperature distribution tends to lengthen the combustion, as cold mass within …
Date: December 13, 2004
Creator: Aceves, S. M.; Flowers, D. L.; Martinez-Frias, J.; Espinosa-Loza, F.; Christensen, M.; Johansson, B. et al.
Object Type: Article
System: The UNT Digital Library
Realizing the Opportunities of Neutron Cross Section Measurements at RIA (open access)

Realizing the Opportunities of Neutron Cross Section Measurements at RIA

The Rare Isotope Accelerator will produce many isotopes at never before seen rates. This will allow for the first time measurements on isotopes very far from stability and new measurement opportunities for unstable nuclei near stability. In fact, the production rates are such that it should be possible to collect 10 micrograms of many isotopes with a half-life of 1 day or more. This ability to make targets of short-lived nuclei enables the possibility of making neutron cross-section measurements important to the astrophysics and the stockpile stewardship communities. But to fully realize this opportunity, the appropriate infrastructure must be included at the RIA facility. This includes isotope harvesting capabilities, radiochemical areas for processing collected material, and an intense, ''mono-energetic'', tunable neutron source. As such, we have been developing a design for neutron source facility to be included at the RIA site. This facility would produce neutrons via intense beams of deuterons and protons on a variety of targets. The facility would also include the necessary radiochemical facilities for target processing. These infrastructure needs will be discussed in addition to the methods that would be employed at RIA for measuring these neutron cross-sections.
Date: October 13, 2004
Creator: Ahle, L; Hausmann, M; Reifarth, R; Roberts, K; Roeben, M; Rusnak, B et al.
Object Type: Article
System: The UNT Digital Library
Search for X-ray induced decay of the 31-yr isomer of 178Hf using synchrotron radiation (open access)

Search for X-ray induced decay of the 31-yr isomer of 178Hf using synchrotron radiation

Isomeric {sup 178}Hf (t{sub 1/2} = 31 yr, E{sub x} = 2.446 MeV, J{sup {pi}} = 16{sup +}) was bombarded by a white beam of x-rays from the Advanced Photon Source at Argonne National Laboratory. A search was made for x-ray induced decay of the isomer by detecting prompt and delayed {gamma} rays associated with the decay. No induced decay was observed. Upper limits for such a process for x-ray energies between 7-100 keV were set. The limits between 7 and 30 keV are below {approx} 3 x 10{sup -27} cm{sup 2}-keV for induced decay that bypasses the 4-s isomer and {approx} 5 x 10{sup -27} cm{sup 2}-keV for induced decay that is delayed through this isomer, orders of magnitude below values at which induced decay was reported previously. These limits are consistent with what is known about the properties of atomic nuclei.
Date: September 13, 2004
Creator: Ahmad, I.; Banar, J. C.; Becker, J. A.; Bredeweg, T. A.; Cooper, J. R.; Gemmell, D. S. et al.
Object Type: Report
System: The UNT Digital Library
MUSE-4 experiment measurements and analysis. (open access)

MUSE-4 experiment measurements and analysis.

This report presents a review of the activities performed by the five teams involved in the MUSE-4 experimental program. More details are provided on the contribution by ANL during the year 9/02 to 9/03. The ANL activity consisted both in direct participation in the experimental measurements and in the physics analysis of the experimental data, mainly for the reactivity level, adjoint flux and fission rate distributions and the analysis of dynamic measurements for reactivity determination techniques in subcritical systems. The results provided to complete the Benchmark organized by the OECD and the CEA on the experiment MUSE-4 are also presented. Deterministic calculations have been performed via the ERANOS code system in connection with JEF2.2, ENDF/B-V and ENDF/B-VI data files.
Date: January 13, 2004
Creator: Aliberti, G.; Imel, G. & Palmiotti, G.
Object Type: Report
System: The UNT Digital Library
Input to the NSF Study on Computational Requirements in Geosciences (open access)

Input to the NSF Study on Computational Requirements in Geosciences

The Computational Physics Group of the Earth Sciences Division focuses much of its effort on improving current understanding of the response of geologic media to strong shock waves, and on the interaction of those waves with underground structures. Two codes have been developed and used to achieve these objectives: LDEC and GEODYN. Both codes are three-dimensional and massively parallel, and they have both been used on LLNLs high performance computing platforms to advance the state of the art in computational geophysics.
Date: December 13, 2004
Creator: Antoun, T; Lomov, I & Morris, J
Object Type: Report
System: The UNT Digital Library
Automatic registration of serial mammary gland sections (open access)

Automatic registration of serial mammary gland sections

We present two new methods for automatic registration of microscope images of consecutive tissue sections. They represent two possibilities for the first step in the 3-D reconstruction of histological structures from serially sectioned tissue blocks. The goal is to accurately align the sections in order to place every relevant shape contained in each image in front of its corresponding shape in the following section before detecting the structures of interest and rendering them in 3D. This is accomplished by finding the best rigid body transformation (translation and rotation) of the image being registered by maximizing a matching function based on the image content correlation. The first method makes use of the entire image information, whereas the second one uses only the information located at specific sites, as determined by the segmentation of the most relevant tissue structures. To reduce computing time, we use a multiresolution pyramidal approach that reaches the best registration transformation in increasing resolution steps. In each step, a subsampled version of the images is used. Both methods rely on a binary image which is a thresholded version of the Sobel gradients of the image (first method) or a set of boundaries manually or automatically obtained that define …
Date: April 13, 2004
Creator: Arganda-Carreras, Ignacio; Fernandez-Gonzalez, Rodrigo & Ortiz-de-Solorzano, Carlos
Object Type: Article
System: The UNT Digital Library
Software Quality System for the Integrated Design and Production Reference V1.00 (open access)

Software Quality System for the Integrated Design and Production Reference V1.00

None
Date: July 13, 2004
Creator: Barter, R H
Object Type: Report
System: The UNT Digital Library
Global analysis of inclusive B decays (open access)

Global analysis of inclusive B decays

In light of the large amount of new experimental data, we revisit the determination of |V{sub cb}| and m{sub b} from inclusive semileptonic and radiative B decays. We study shape variables to order {Lambda}{sub QCD}{sup 3}/m{sub b}{sup 3} and {alpha}{sub s}{sup 2}{beta}{sub 0}, and include the order {alpha}{sub s} {Lambda}{sub QCD}/m{sub b} correction to the hadron mass spectrum in semileptonic decay, which improves the agreement with the data. We focus on the 1S and kinetic mass schemes for the b quark, with and without expanding m{sub b}-m{sub c} in HQET. We perform fits to all available data from BABAR, BELLE, CDF, CLEO, and DELPHI, discuss the theoretical uncertainties, and compare with earlier results. We find |V{sub cb}| = (41.9 {+-} 0.6 {+-} 0.1{sub {tau}{sub B}}) x 10{sup -3} and m{sub b}{sup 1S} = 4.68 {+-} 0.04GeV, including our estimate of the theoretical uncertainty in the fit.
Date: August 13, 2004
Creator: Bauer, Christian W.; Ligeti, Zoltan; Luke, Michael; Manohar, Aneesh & Trott, Michael
Object Type: Article
System: The UNT Digital Library
National Environmental Education Act of 1990: Overview, Implementation, and Reauthorization Issues (open access)

National Environmental Education Act of 1990: Overview, Implementation, and Reauthorization Issues

None
Date: April 13, 2004
Creator: Bearden, David M.
Object Type: Report
System: The UNT Digital Library
Update of ENDL U(n,2n), U(n,gamma), U(n,f) Evaluations (open access)

Update of ENDL U(n,2n), U(n,gamma), U(n,f) Evaluations

The authors are in the re-evaluating of all the actinide cross section evaluations in LLNL's ENDL database, starting with uranium and focusing on inventory changing reactions. This article describes their first serious pass at updating the uranium cross section data, including estimates of cross section uncertainties. Furthermore, they are developing new tools to automate the re-evaluation and this article contains some preliminary results from these codes, namely the {sup 235}U(n, 2n) and {sup 238}U(n, 2n) evaluations.
Date: February 13, 2004
Creator: Beck, B.; Brown, D. A. & McNabb, D. P.
Object Type: Report
System: The UNT Digital Library
Including dislocation flux in a continuum crystal plasticity model to produce size scale effects (open access)

Including dislocation flux in a continuum crystal plasticity model to produce size scale effects

A novel model has been developed to capture size scale and gradient effects within the context of continuum crystal plasticity by explicitly incorporating details of dislocation transport, coupling dislocation transport to slip, evolving spatial distributions of dislocations consistent with the flux, and capturing the interactions among various dislocation populations. Dislocation flux and density are treated as nodal degrees of freedom in the finite element model, and they are determined as part of the global system of equations. The creation, annihilation and flux of dislocations between elements are related by transport equations. Crystallographic slip is coupled to the dislocation flux and the stress state. The resultant gradients in dislocation density and local lattice rotations are analyzed for geometrically necessary and statistically stored dislocation contents that contribute to strength and hardening. Grain boundaries are treated as surfaces where dislocation flux is restricted depending on the relative orientations of the neighboring grains. Numerical results show different behavior near free surfaces and non-deforming surfaces resulting from differing levels of dislocation transmission. Simulations also show development of dislocation pile-ups at grain boundaries and an increase in flow strength reminiscent of the Hall-Petch model. The dislocation patterns have a characteristic size independent of the numerical discretization.
Date: February 13, 2004
Creator: Becker, R.; Arsenlis, A.; Bulatov, V. V. & Parks, D. M.
Object Type: Article
System: The UNT Digital Library
Neutrons and Granite: Transport and Activation (open access)

Neutrons and Granite: Transport and Activation

In typical ground materials, both energy deposition and radionuclide production by energetic neutrons vary with the incident particle energy in a non-monotonic way. We describe the overall balance of nuclear reactions involving neutrons impinging on granite to demonstrate these energy-dependencies. While granite is a useful surrogate for a broad range of soil and rock types, the incorporation of small amounts of water (hydrogen) does alter the balance of nuclear reactions.
Date: April 13, 2004
Creator: Bedrossian, P J
Object Type: Report
System: The UNT Digital Library
Institutional plan FY 2004 - FY 2008. (open access)

Institutional plan FY 2004 - FY 2008.

Argonne's mission is to serve DOE and national security by advancing the frontiers of knowledge, by creating and operating forefront scientific user facilities, and by providing innovative and effective approaches and solutions to energy, environmental, and security challenges to national and global well-being, in the near and long term, as a contributing member of the DOE laboratory system. We contribute significantly to DOE's mission in science, energy resources, environmental stewardship, and national security, with lead roles in the areas of science, operation of scientific facilities, and energy. In accomplishing our mission, we partner with DOE, other federal laboratories and agencies, the academic community, and the private sector. Argonne is pursuing ten visionary strategic goals to deliver extraordinary science and technology with significant value to the nation: (1) Develop the technologies and infrastructure needed to produce, store, and distribute hydrogen fuel. (2) Close the nuclear fuel cycle, reducing the cost of nuclear waste disposal by billions of dollars and disposing of weapons-grade plutonium and actinides. (3) Develop advanced nuclear power technologies that are safe, economical, proliferation-resistant, and environmentally sustainable. (4) Plan, design, construct, and operate the Rare Isotope Accelerator (RIA) and make fundamental discoveries in nuclear physics and astrophysics. (5) Construct …
Date: February 13, 2004
Creator: Beggs, S. D.
Object Type: Report
System: The UNT Digital Library
Gasoline Prices: Policies and Proposals (open access)

Gasoline Prices: Policies and Proposals

This report details the information related to gasoline prices and discusses policies and proposals.
Date: August 13, 2004
Creator: Behrens, Carl E. & Glover, Carol
Object Type: Report
System: The UNT Digital Library
Laboratory simulation of cometary x rays using a high-resolution microcalorimeter (open access)

Laboratory simulation of cometary x rays using a high-resolution microcalorimeter

X-ray emission following charge exchange has been studied on the University of California Lawrence Livermore National Laboratory electron beam ion traps EBIT-I and EBIT-II using a high-resolution microcalorimeter. The measured spectra include the K-shell emission from hydrogen-like and helium-like C, N, O, and Ne needed for simulations of cometary x-ray emission. A comparison of the spectra produced in the interaction of O{sup 8+} with N{sub 2} and CH{sub 4} is presented that illustrates the dependence of the observed spectrum on the interaction gas.
Date: August 13, 2004
Creator: Beiersdorfer, P; Chen, H; Boyce, K R; Brown, G V; Kelley, R L; Kilbourne, C A et al.
Object Type: Article
System: The UNT Digital Library
Adequacy of the Army’s FY2004 Funding for Operations in Iraq (open access)

Adequacy of the Army’s FY2004 Funding for Operations in Iraq

The article summarizes the deficiency in the Army's budget as tensions rose in Iraq in 2004. Moreover, the report includes monthly data on the cost of military action in Iraq and recommends the gathering of further data to better assess the cost. Richard Myers, Chairman of the Joint Chiefs of Staff estimated a budget shortfall of 4 billion dollars, and explained that the Department of Defense (DOD) was assessing if further funds would be needed.
Date: May 13, 2004
Creator: Belasco, Amy
Object Type: Report
System: The UNT Digital Library
Target Diagnostic Technology Research & Development for the LLNL ICF and HED Program (open access)

Target Diagnostic Technology Research & Development for the LLNL ICF and HED Program

The National Ignition Facility is operational at LLNL. The ICF and HED programs at LLNL have formed diagnostic research and development groups to institute improvements outside the charter of core diagnostics. We will present data from instrumentation being developed. A major portion of our work is improvements to detectors and readout systems. We have efforts related to CCD device development. Work has been done in collaboration with the University of Arizona to back thin a large format CCD device. We have developed in collaboration with a commercial vendor a large format, compact CCD system. We have coupled large format CCD systems to our optical and x-ray streak cameras leading to improvements in resolution and dynamic range. We will discuss gate-width and uniformity improvements to MCP-based framing cameras. We will present data from single shot data link work and discuss technology aimed at improvements of dynamic range for high-speed transient measurements from remote locations.
Date: April 13, 2004
Creator: Bell, P; Landen, O; Weber, F; Lowry, M; Bennett, C; Kimbrough, J et al.
Object Type: Article
System: The UNT Digital Library
The BDGP gene disruption project: Single transposon insertions associated with 40 percent of Drosophila genes (open access)

The BDGP gene disruption project: Single transposon insertions associated with 40 percent of Drosophila genes

The Berkeley Drosophila Genome Project (BDGP) strives to disrupt each Drosophila gene by the insertion of a single transposable element. As part of this effort, transposons in more than 30,000 fly strains were localized and analyzed relative to predicted Drosophila gene structures. Approximately 6,300 lines that maximize genomic coverage were selected to be sent to the Bloomington Stock Center for public distribution, bringing the size of the BDGP gene disruption collection to 7,140 lines. It now includes individual lines predicted to disrupt 5,362 of the 13,666 currently annotated Drosophila genes (39 percent). Other lines contain an insertion at least 2 kb from others in the collection and likely mutate additional incompletely annotated or uncharacterized genes and chromosomal regulatory elements. The remaining strains contain insertions likely to disrupt alternative gene promoters or to allow gene mis-expression. The expanded BDGP gene disruption collection provides a public resource that will facilitate the application of Drosophila genetics to diverse biological problems. Finally, the project reveals new insight into how transposons interact with a eukaryotic genome and helps define optimal strategies for using insertional mutagenesis as a genomic tool.
Date: January 13, 2004
Creator: Bellen, Hugo J.; Levis, Robert W.; Liao, Guochun; He, Yuchun; Carlson, Joseph W.; Tsang, Garson et al.
Object Type: Article
System: The UNT Digital Library
Recent Results From Optimization Studies of Linear Non-Scaling Ffags for Muon Acceleration. (open access)

Recent Results From Optimization Studies of Linear Non-Scaling Ffags for Muon Acceleration.

Because of the highly repetitive nature and simple cell structure of FFAG lattices, it is possible to automatically design these lattices. In designing an FFAG lattice, one will try to meet certain constraints and then minimize some cost function by varying any remaining free parameters. I will first review previously published work on optimized FFAG design. Then I will describe recent advances in the understanding of linear non-scaling FFAG design that have come from these optimization techniques. I will describe how the lattice designs depend on some input parameters to the design. Finally, I will present a set of FFAG lattices that are optimized for muon acceleration using these techniques.
Date: October 13, 2004
Creator: Berg, J. S.
Object Type: Article
System: The UNT Digital Library
Poroelastic fluid effects on shear for rocks with soft anisotropy (open access)

Poroelastic fluid effects on shear for rocks with soft anisotropy

A general analysis of poroelasticity for vertical transverse isotropy (VTI) shows that four eigenvectors are pure shear modes with no coupling to the pore-fluid mechanics. The remaining two eigenvectors are linear combinations of pure compression and uniaxial shear, both of which are coupled to the fluid mechanics. After reducing the problem to a 2 x 2 system, the analysis shows in a relatively elementary fashion how a poroelastic system with isotropic solid elastic frame, but with anisotropy introduced through the poroelastic coefficients, interacts with the mechanics of the pore fluid and produces shear dependence on fluid properties in the overall poroelastic system. The analysis shows for example that this effect is always present (though sometimes small in magnitude) in the systems studied, and can be quite large (on the order of 10 to 20%) for wave propagation studies in some real granites and sandstones, including Spirit River sandstone and Schuler-Cotton Valley sandstone. Some of the results quoted here are obtained by using a new product formula relating local bulk and uniaxial shear energy to the product of the two eigenvalues that are coupled to the fluid mechanics. This product formula was first derived in prior work, but is given a …
Date: April 13, 2004
Creator: Berger, E. L.
Object Type: Article
System: The UNT Digital Library
LLNL Scientists Use NERSC to Advance Global Aerosol Simulations (open access)

LLNL Scientists Use NERSC to Advance Global Aerosol Simulations

While ''greenhouse gases'' have been the focus of climate change research for a number of years, DOE's ''Aerosol Initiative'' is now examining how aerosols (small particles of approximately micron size) affect the climate on both a global and regional scale. Scientists in the Atmospheric Science Division at Lawrence Livermore National Laboratory (LLNL) are using NERSC's IBM supercomputer and LLNL's IMPACT (atmospheric chemistry) model to perform simulations showing the historic effects of sulfur aerosols at a finer spatial resolution than ever done before. Simulations were carried out for five decades, from the 1950s through the 1990s. The results clearly show the effects of the changing global pattern of sulfur emissions. Whereas in 1950 the United States emitted 41 percent of the world's sulfur aerosols, this figure had dropped to 15 percent by 1990, due to conservation and anti-pollution policies. By contrast, the fraction of total sulfur emissions of European origin has only dropped by a factor of 2 and the Asian emission fraction jumped six fold during the same time, from 7 percent in 1950 to 44 percent in 1990. Under a special allocation of computing time provided by the Office of Science INCITE (Innovative and Novel Computational Impact on Theory …
Date: October 13, 2004
Creator: Bergmann, D. J.; Chuang, C. & Rotman, D.
Object Type: Article
System: The UNT Digital Library
A Low-Cost, Real-Time Network for Radiological Monitoring Around Nuclear Facilities (open access)

A Low-Cost, Real-Time Network for Radiological Monitoring Around Nuclear Facilities

A low-cost, real-time radiological sensor network for emergency response has been developed and deployed at the Lawrence Livermore National Laboratory (LLNL). The Real-Time Radiological Area Monitoring (RTRAM) network is comprised of 16 Geiger-Mueller (GM) sensors positioned on the site perimeter to continuously monitor radiological conditions as part of LLNL's comprehensive environment/safety/health protection program. The RTRAM network sensor locations coincide with wind sector directions to provide thorough coverage of the one square mile site. These low-power sensors transmit measurement data back to a central command center (CCC) computer through the LLNL telecommunications infrastructure. Alarm conditions are identified by comparing current data to predetermined threshold parameters and are validated by comparison with plausible dispersion modeling scenarios and prevailing meteorological conditions. Emergency response personnel are notified of alarm conditions by automatic radio- and computer- based notifications. A secure intranet provides emergency response personnel with current condition assessment data that enable them to direct field response efforts remotely. This system provides a low-cost real-time radiation monitoring solution that is easily converted to incorporate both a hard-wired interior perimeter with strategically positioned wireless secondary and tertiary concentric remote locations. These wireless stations would be configured with solar voltaic panels that provide current to recharge batteries …
Date: August 13, 2004
Creator: Bertoldo, N A
Object Type: Report
System: The UNT Digital Library
Improved Pinhole-Apertured Point-Projection Backlighter Geometry (open access)

Improved Pinhole-Apertured Point-Projection Backlighter Geometry

Pinhole-apertured point-projection x-ray radiography is an important diagnostic technique for obtaining high resolution, high contrast, and large field-of-view images used to diagnose the hydrodynamic evolution of high energy density experiments. In this technique, a pinhole aperture is placed between a laser irradiated foil (x-ray source) and an imaging detector. In this letter, we present an improved backlighter geometry that utilizes a tilted pinhole for debris mitigation and a front-side illuminated backlighter foil for improved photon statistics.
Date: April 13, 2004
Creator: Blue, B.; Robey, H. F. & Hansen, J. F.
Object Type: Article
System: The UNT Digital Library
Comparison of AEO 2005 natural gas price forecast to NYMEX futures prices (open access)

Comparison of AEO 2005 natural gas price forecast to NYMEX futures prices

On December 9, the reference case projections from ''Annual Energy Outlook 2005 (AEO 2005)'' were posted on the Energy Information Administration's (EIA) web site. As some of you may be aware, we at LBNL have in the past compared the EIA's reference case long-term natural gas price forecasts from the AEO series to contemporaneous natural gas prices that can be locked in through the forward market, with the goal of better understanding fuel price risk and the role that renewables play in mitigating such risk. As such, we were curious to see how the latest AEO gas price forecast compares to the NYMEX natural gas futures strip. This brief memo presents our findings. As a refresher, our past work in this area has found that over the past four years, forward natural gas contracts (e.g., gas futures, swaps, and physical supply) have traded at a premium relative to contemporaneous long-term reference case gas price forecasts from the EIA. As such, we have concluded that, over the past four years at least, levelized cost comparisons of fixed-price renewable generation with variable price gas-fired generation that have been based on AEO natural gas price forecasts (rather than forward prices) have yielded results …
Date: December 13, 2004
Creator: Bolinger, Mark & Wiser, Ryan
Object Type: Report
System: The UNT Digital Library