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Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
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1

An exposure assessment survey of the Mont Belvieu polyethylene plant  

E-Print Network [OSTI]

to selected employees. The objectives included determining the amount of occupational chemical, dust, noise, and heat-stress exposure experienced by those selected workers. Data collected from job descriptions, questionnaires, walk-through surveys and personal...

Tucker, Thomas Franklin

1997-01-01T23:59:59.000Z

2

Canopy hot-spot as crop identifier  

SciTech Connect (OSTI)

Illuminating any reflective rough or structured surface by a directional light source results in an angular reflectance distribution that shows a narrow peak in the direction of retro-reflection. This is called the Heiligenschein or hot-spot of vegetation canopies and is caused by mutual shading of leaves. The angular intensity distribution of the hot-spot, its brightness and slope, are therefore indicators of the plant's geometry. We propose the use of hot-spot characteristics as crop identifiers in satellite remote sensing because the canopy hot-spot carries information about plant stand architecture that is more distinctive for different plant species than, for instance, their spectral reflectance characteristics. A simple three-dimensional Monte Carlo/ray tracing model and an analytic two-dimensional model are developed to estimate the angular distribution of the hot-spot as a function of the size of the plant leaves. The results show that the brightness-distribution and slope of the hot-spot change distinctively for different leaf sizes indicating a much more peaked maximum for the smaller leaves.

Gerstl, S.A.W.; Simmer, C.; Powers, B.J.

1986-05-01T23:59:59.000Z

3

Utility spot pricing, California  

E-Print Network [OSTI]

The objective of the present spot pricing study carried out for SCE and PG&E is to develop the concepts which wculd lead to an experimental design for spot pricing in the two utilities. The report suggests a set of experiments ...

Schweppe, Fred C.

1982-01-01T23:59:59.000Z

4

Reactor hot spot analysis  

SciTech Connect (OSTI)

The principle methods for performing reactor hot spot analysis are reviewed and examined for potential use in the Applied Physics Division. The semistatistical horizontal method is recommended for future work and is now available as an option in the SE2-ANL core thermal hydraulic code. The semistatistical horizontal method is applied to a small LMR to illustrate the calculation of cladding midwall and fuel centerline hot spot temperatures. The example includes a listing of uncertainties, estimates for their magnitudes, computation of hot spot subfactor values and calculation of two sigma temperatures. A review of the uncertainties that affect liquid metal fast reactors is also presented. It was found that hot spot subfactor magnitudes are strongly dependent on the reactor design and therefore reactor specific details must be carefully studied. 13 refs., 1 fig., 5 tabs.

Vilim, R.B.

1985-08-01T23:59:59.000Z

5

Spot-spraying Johnsongrass.  

E-Print Network [OSTI]

of naphtha and diesel fuel oil is the oil spray most generally used. Various other oil mixtures may be used for economy, for increased contact toxicity, or for a combination of contact toxicity and residual effectiveness. Oil sprays kill on contact... mixture of 40 pounds of sodium TCA and 20 pounds of sodium dalapon can be used for spot-treating sparsely infested cotton fields. It is a knock-out spray under some conditions. Maleic hydrazide (MH-30) is a translocated growth inhibitor with no residual...

Rea, H. E.

1958-01-01T23:59:59.000Z

6

Spot-Oiling Johnsongrass.  

E-Print Network [OSTI]

I TEXAS AGRICULTURAL EXTENSIO-N SERVICE G. G. Gibson, Director, College Station, Texas [Blank Page in Original Bulletin] I the bast I ir used the low I . .. 1 the fol or mort , needed SPOT-OILING JOHNSONGRASS H. E. Rea, M. J. Norris..., and Fred C. Elliott* Texas A. & M. College System ~HNSONGRASS CAN BE killed to the i ground by the application of 1 / 3 teaspoonful of a herbicidal oil to the crown of each stem. Eradication of established Johnsongrass can be obtained in a single...

Elliott, Fred C.; Norris, M. J.; Rea, H. E.

1955-01-01T23:59:59.000Z

7

Utility spot pricing study : Wisconsin  

E-Print Network [OSTI]

Spot pricing covers a range of electric utility pricing structures which relate the marginal costs of electric generation to the prices seen by utility customers. At the shortest time frames prices change every five ...

Caramanis, Michael C.

1982-01-01T23:59:59.000Z

8

MTBE still in poor health, despite the Clean Air Act  

SciTech Connect (OSTI)

After the second winter oxygenated fuels program of the 1990 Clean Air Act, producers of methyl tert-butyl ether (MTBE) are still feeling the chill of poor profitability. Despite the strong demand growth for MTBE to meet oxygen requirements in reformulated gasoline (RFG), oversupply still dogs the market. That, combined with a run-up in feedstock prices, has seen margins for MTBE markers all but evaporate. And it seems matters are likely to get worse before they get better. This week, Belvieu Environmental Fuels (BEF; Houston) expects to startup its 15,000-bbl/day MTBE plant at Mont Belvieu, TX. In late July, Texaco will start up its 15,000-bbl/day MTBE/propylene oxide (PO) plant at Port Neches, TX. In addition, a rash of refinery-based MTBE and tert-amyl methyl ether projects are nearing completion. {open_quotes}Profitability in MTBE has been extremely poor,{close_quotes} says Marvin O. Schlanger, president of Arco Chemical Americas, the largest MTBE producer. There has, however, been some recent recovery on the spot market, with MTBE moving from less than 60 cts/gal to near cash-cost levels of 70 cts/gal. But contract prices remain depressed, and strength in butane and methanol pricing have all buy wiped out any gains in MTBE.

Wood, A.

1994-05-25T23:59:59.000Z

9

Monte Carlo fundamentals  

SciTech Connect (OSTI)

This report is composed of the lecture notes from the first half of a 32-hour graduate-level course on Monte Carlo methods offered at KAPL. These notes, prepared by two of the principle developers of KAPL`s RACER Monte Carlo code, cover the fundamental theory, concepts, and practices for Monte Carlo analysis. In particular, a thorough grounding in the basic fundamentals of Monte Carlo methods is presented, including random number generation, random sampling, the Monte Carlo approach to solving transport problems, computational geometry, collision physics, tallies, and eigenvalue calculations. Furthermore, modern computational algorithms for vector and parallel approaches to Monte Carlo calculations are covered in detail, including fundamental parallel and vector concepts, the event-based algorithm, master/slave schemes, parallel scaling laws, and portability issues.

Brown, F.B.; Sutton, T.M.

1996-02-01T23:59:59.000Z

10

Blind spots between quantum states  

E-Print Network [OSTI]

The overlap of a large quantum state with its image, under tiny translations, oscillates swiftly. We here show that complete orthogonality occurs generically at isolated points. Decoherence, in the Markovian approximation, lifts the correlation minima from zero much more quickly than the Wigner function is smoothed into a positive phase space distribution. In the case of a superposition of coherent states, blind spots depend strongly on positions and amplitudes of the components, but they are only weakly affected by relative phases and the various degrees and directions of squeezing. The blind spots for coherent state triplets are special in that they lie close to an hexagonal lattice: Further superpositions of translated triplets, specified by nodes of one of the sublattices, are quasi-orthogonal to the original triplet and to any state, likewise constructed on the other sublattice.

Eduardo Zambrano; Alfredo M Ozorio de Almeida

2009-09-30T23:59:59.000Z

11

Monte Carlo event generators  

SciTech Connect (OSTI)

I review recent progress in the physics of parton shower Monte Carlos, emphasizing the ideas which allow the inclusion of higher-order matrix elements into the framework of event generators.

Frixione, Stefano [INFN, Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

2005-10-06T23:59:59.000Z

12

Hot Spot | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to: navigation,Ohio:GreerHi GtelHomer, Alaska:Horace, NorthHorvatic JumpOpenHotPot,Spot

13

Resistance Spot Welding of Galvanized Steel: Part II. Mechanisms of Spot Weld Nugget Formation  

E-Print Network [OSTI]

( l Resistance Spot Welding of Galvanized Steel: Part II. Mechanisms of Spot Weld Nugget Formation S. A. GEDEON and T. W. EAGAR Dynamic inspection monitoring of the weld current, voltage, resistance of material variations and weld process parameter modifications on resistance spot welding of coated

Eagar, Thomas W.

14

BLIND SPOTS OF QUALITATIVE SIMULATORS Nuri Tasdemir  

E-Print Network [OSTI]

BLIND SPOTS OF QUALITATIVE SIMULATORS by Nuri Ta¸sdemir BS, in Electrical and Electronics in Computer Engineering Bogazi¸ci University 2007 #12;ii BLIND SPOTS OF QUALITATIVE SIMULATORS APPROVED BY: Prof. A.C. Cem Say . . . . . . . . . . . . . . . . . . . (Thesis Supervisor) Prof. H. Levent Akin

15

Monte Carlo photon benchmark problems  

SciTech Connect (OSTI)

Photon benchmark calculations have been performed to validate the MCNP Monte Carlo computer code. These are compared to both the COG Monte Carlo computer code and either experimental or analytic results. The calculated solutions indicate that the Monte Carlo method, and MCNP and COG in particular, can accurately model a wide range of physical problems.

Whalen, D.J.; Hollowell, D.E.; Hendricks, J.S.

1991-01-01T23:59:59.000Z

16

Short-lived spots in solar-like stars as observed by CoRoT  

E-Print Network [OSTI]

Context. CoRoT light curves have an unprecedented photometric quality, having simultaneously a high signal-to-noise ratio, a long time span and a nearly continuous duty-cycle. Aims. We analyse the light-curves of four bright targets observed in the seismology field and study short-lived small spots in solar-like stars. Methods. We present a simple spot modeling by iterative analysis. Its ability to extract relevant parameters is ensured by implementing relaxation steps to avoid convergence to local minima of the sum of the residuals between observations and modeling. The use of Monte-Carlo simulations allows us to estimate the performance of the fits. Results. Our starspot modeling gives a representation of the spots on these stars in agreement with other well tested methods. Within this framework, parameters such as rigid-body rotation and spot lifetimes seem to be precisely determined. Then, the lifetime/rotation period ratios are in the range 0.5 - 2, and there is clear evidence for differential rotation.

Mosser, B; Lanza, A F; Hulot, J C; Catala, C; Baglin, A; Auvergne, M

2009-01-01T23:59:59.000Z

17

POWER '99 Conference 1 Stochastic Models of Electricity Spot Price  

E-Print Network [OSTI]

spread call options. power spot price delivery at PV gas spot price SoCal system 8000 heat rate When power. When the spot market implied heat rate is below the unit operating heat rate, generator should1 POWER '99 Conference 1 Stochastic Models of Electricity Spot Price and their Applications Shijie

California at Berkeley. University of

18

Relationship between Hot Spot Residues and Ligand Binding Hot Spots in Protein-Protein Interfaces  

E-Print Network [OSTI]

, while identification of a hot spot by alanine scanning establishes the potential to generate substantial, termed "hot spots", that comprise the subset of residues that contribute the bulk of the binding free proposed as prime targets for drug binding.1,4 The established approach to the identification of such hot

Vajda, Sandor

19

Discriminative Keyword Spotting David Grangier1  

E-Print Network [OSTI]

Laboratories America, Princeton, NJ, USA 2 IDIAP Research Institute, Martigny, Switzerland 3 Google Inc., Mountain View, CA, USA This chapter introduces a discriminative method for detecting and spotting keywords and transition models, or the Expectation-Maximization (EM) training procedure, which is prone to convergence

Tomkins, Andrew

20

Sourcing Flexibility, Spot Trading, and Procurement Contract Structure  

E-Print Network [OSTI]

We analyze the structure and pricing of option contracts for an industrial good in the presence of spot trading. We combine the analysis of spot trading and buyers' disparate private valuations for different suppliers' ...

Pei, Pamela Pen-Erh

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Friction Stir Spot Welding of Advanced High Strength Steels ...  

Energy Savers [EERE]

Stir Spot Welding of Advanced High Strength Steels (AHSS) Friction Stir Spot Welding of Advanced High Strength Steels (AHSS) Presentation from the U.S. DOE Office of Vehicle...

22

EECBG Success Story: Bright Green Spot: Fort Worth Library |...  

Broader source: Energy.gov (indexed) [DOE]

Bright Green Spot: Fort Worth Library EECBG Success Story: Bright Green Spot: Fort Worth Library September 30, 2010 - 9:53am Addthis Fort Worth's Central Library is seeing...

23

Bright Green Spot: Fort Worth Library | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Bright Green Spot: Fort Worth Library Bright Green Spot: Fort Worth Library September 30, 2010 - 4:07pm Addthis Lindsay Gsell Fort Worth's Central Library is seeing tremendous...

24

Automated Spot Weld Inspection using Infrared Thermography  

SciTech Connect (OSTI)

An automated non-contact and non-destructive resistance spot weld inspection system based on infrared (IR) thermography was developed for post-weld applications. During inspection, a weld coupon was heated up by an auxiliary induction heating device from one side of the weld, while the resulting thermal waves on the other side were observed by an IR camera. The IR images were analyzed to extract a thermal signature based on normalized heating time, which was then quantitatively correlated to the spot weld nugget size. The use of normalized instead of absolute IR intensity was found to be useful in minimizing the sensitivity to the unknown surface conditions and environment interference. Application of the IR-based inspection system to different advanced high strength steels, thickness gauges and coatings were discussed.

Chen, Jian [ORNL] [ORNL; Zhang, Wei [ORNL] [ORNL; Yu, Zhenzhen [ORNL] [ORNL; Feng, Zhili [ORNL] [ORNL

2012-01-01T23:59:59.000Z

25

The fractal nature of vacuum arc cathode spots  

SciTech Connect (OSTI)

Cathode spot phenomena show many features of fractals, for example self-similar patterns in the emitted light and arc erosion traces. Although there have been hints on the fractal nature of cathode spots in the literature, the fractal approach to spot interpretation is underutilized. In this work, a brief review of spot properties is given, touching the differences between spot type 1 (on cathodes surfaces with dielectric layers) and spot type 2 (on metallic, clean surfaces) as well as the known spot fragment or cell structure. The basic properties of self-similarity, power laws, random colored noise, and fractals are introduced. Several points of evidence for the fractal nature of spots are provided. Specifically power laws are identified as signature of fractal properties, such as spectral power of noisy arc parameters (ion current, arc voltage, etc) obtained by fast Fourier transform. It is shown that fractal properties can be observed down to the cutoff by measurement resolution or occurrence of elementary steps in physical processes. Random walk models of cathode spot motion are well established: they go asymptotically to Brownian motion for infinitesimal step width. The power spectrum of the arc voltage noise falls as 1/f {sup 2}, where f is frequency, supporting a fractal spot model associated with Brownian motion.

Anders, Andre

2005-05-27T23:59:59.000Z

26

Berkeley Lab's SPOT Suite Transforms Beamline Science  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone6 M. Babzien, I. Ben-Zvi,Benefits PlanabPerformanceSPOT Suite

27

Is Monte Carlo embarrassingly parallel?  

SciTech Connect (OSTI)

Monte Carlo is often stated as being embarrassingly parallel. However, running a Monte Carlo calculation, especially a reactor criticality calculation, in parallel using tens of processors shows a serious limitation in speedup and the execution time may even increase beyond a certain number of processors. In this paper the main causes of the loss of efficiency when using many processors are analyzed using a simple Monte Carlo program for criticality. The basic mechanism for parallel execution is MPI. One of the bottlenecks turn out to be the rendez-vous points in the parallel calculation used for synchronization and exchange of data between processors. This happens at least at the end of each cycle for fission source generation in order to collect the full fission source distribution for the next cycle and to estimate the effective multiplication factor, which is not only part of the requested results, but also input to the next cycle for population control. Basic improvements to overcome this limitation are suggested and tested. Also other time losses in the parallel calculation are identified. Moreover, the threading mechanism, which allows the parallel execution of tasks based on shared memory using OpenMP, is analyzed in detail. Recommendations are given to get the maximum efficiency out of a parallel Monte Carlo calculation. (authors)

Hoogenboom, J. E. [Delft Univ. of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Delft Nuclear Consultancy, IJsselzoom 2, 2902 LB Capelle aan den IJssel (Netherlands)

2012-07-01T23:59:59.000Z

28

Monte Carlo calculations of nuclei  

SciTech Connect (OSTI)

Nuclear many-body calculations have the complication of strong spin- and isospin-dependent potentials. In these lectures the author discusses the variational and Green`s function Monte Carlo techniques that have been developed to address this complication, and presents a few results.

Pieper, S.C. [Argonne National Lab., IL (United States). Physics Div.

1997-10-01T23:59:59.000Z

29

Friction Stir Spot Welding of Advanced High Strength Steels II...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

II Friction Stir Spot Welding of Advanced High Strength Steels II 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation...

30

Shell model Monte Carlo methods  

SciTech Connect (OSTI)

We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, thermal behavior of {gamma}-soft nuclei, and calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. 87 refs.

Koonin, S.E. [California Inst. of Tech., Pasadena, CA (United States). W.K. Kellogg Radiation Lab.; Dean, D.J. [Oak Ridge National Lab., TN (United States)

1996-10-01T23:59:59.000Z

31

Monte Carlo methods in ICF  

SciTech Connect (OSTI)

Monte Carlo methods appropriate to simulate the transport of x-rays, neutrons, ion and electrons in Inertial Confinement Fusion targets are described and analyzed. The Implicit Monte Carlo method of x-ray transport handles symmetry within indirect drive ICF hohlraums well, but can be improved 50X in efficiency by angular biasing the x-rays towards the fuel capsule. Accurate simulation of thermonuclear burns nd burn diagnostics involves detailed particle source spectra, charged particle ranges, inflight reaction kinematics, corrections for bulk and thermal Doppler effects and variance reduction to obtain adequate statistics for rare events. It is found that the effects of angular Coulomb scattering must be included in models of charged particle transport through heterogeneous materials.

Zimmerman, G.B.

1997-06-24T23:59:59.000Z

32

Parallel Monte Carlo reactor neutronics  

SciTech Connect (OSTI)

The issues affecting implementation of parallel algorithms for large-scale engineering Monte Carlo neutron transport simulations are discussed. For nuclear reactor calculations, these include load balancing, recoding effort, reproducibility, domain decomposition techniques, I/O minimization, and strategies for different parallel architectures. Two codes were parallelized and tested for performance. The architectures employed include SIMD, MIMD-distributed memory, and workstation network with uneven interactive load. Speedups linear with the number of nodes were achieved.

Blomquist, R.N.; Brown, F.B.

1994-03-01T23:59:59.000Z

33

Modelling spot and forward prices for energy companies  

E-Print Network [OSTI]

Modelling spot and forward prices for energy companies Dafydd Steele MSc Stochastics and Financial forward and spot prices for energy com- panies. The two main ways of modelling power prices are stochastic Mathematics dafydd.steele@edf-energy.com August 5, 2010 #12;Abstract The focus of this thesis is on modelling

Bhulai, Sandjai

34

A NONGAUSSIAN ORNSTEINUHLENBECK PROCESS FOR ELECTRICITY SPOT PRICE MODELING AND  

E-Print Network [OSTI]

A NON­GAUSSIAN ORNSTEIN­UHLENBECK PROCESS FOR ELECTRICITY SPOT PRICE MODELING AND DERIVATIVES for analytical pricing of electricity forward and futures contracts. Electricity forward and futures contracts to capture the observed dynamics of electricity spot prices. We also discuss the pricing of European call

Kallsen, Jan

35

Cinematography of Resistance Spot Welding of Galvanized Steel Sheet  

E-Print Network [OSTI]

Cinematography of Resistance Spot Welding of Galvanized Steel Sheet Preweld and postweld current modifications on the resistance spot welding of galvanized steel sheet ·are analyzed using high phenomena through· out the weld process are discussed. In addition. the duration of current modifi· cation

Eagar, Thomas W.

36

Hot Spot Conditions during Cavitation in Water Yuri T. Didenko,  

E-Print Network [OSTI]

Hot Spot Conditions during Cavitation in Water Yuri T. Didenko, William B. McNamara III-13 the effective hot spot temperature during aqueous cavitation remains unresolved. Given the importance of aqueous cavitation (sonography and bioeffects of ultrasound, sonochemical remediation of aqueous pollutants

Suslick, Kenneth S.

37

Monte Carlo simulations of dose near a nonradioactive gold seed  

SciTech Connect (OSTI)

The relative doses and hot/cold spot positions around a non-radioactive gold seed, irradiated by a 6 or 18 MV photon beam in water, were calculated using Monte Carlo simulation. Phase space files of 6 and 18 MV photon beams with a field size of 1x1 cm{sup 2} were generated by a Varian 21 EX linear accelerator using the EGSnrc and BEAMnrc code. The seed (1.2x1.2x3.2 mm{sup 3}) was positioned at the isocenter in a water phantom (20x20x20 cm{sup 2}) with source-to-axis distance=100 cm. For the single beam geometry, the relative doses (normalized to the dose at 5 mm distance above the isocenter) at the upstream seed surface were calculated to be 1.64 and 1.56 for the 6 and 18 MV beams respectively when the central beam axis (CAX) is parallel to the width of the seed. These doses were slightly higher than those (1.58 and 1.52 for 6 and 18 MV beams respectively) calculated when the CAX is perpendicular to the width of the seed. Compared to the relative dose profiles with the same beam geometry without the seed in the water phantom, the presence of the seed affects the dose distribution at about 3 mm distance beyond both the upstream and downstream seed surface. For a pair of opposing beams with equal and unequal beam weight, the hot and cold spots of both opposing beams were mixed. For a 360 degree photon arc around the longitudinal axis of the seed, the relative dose profile along the width of the seed was similar to that of the opposing beam pair, except the former geometry has a larger dose gradient near the seed surface. In this study, selected results from our simulation were compared to previous measurements using film dosimetry.

Chow, James C. L.; Grigorov, Grigor N. [Department of Radiation Oncology, University of Toronto and Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, ON N2G 1G3 (Canada) and Department of Physics, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada); Medical Physics Department, Grand River Regional Cancer Center, Grand River Hospital, 835 King Street West, Kitchener, ON N2G 1G3 (Canada)

2006-12-15T23:59:59.000Z

38

Hottest spot temperatures in ventilated dry type transformers  

SciTech Connect (OSTI)

The hottest spot temperature allowance to be used for the different insulation system temperature classes is a major unknown facing IEEE Working Groups developing standards and loading guides for ventilated dry type transformers. In 1944, the hottest spot temperature allowance for ventilated dry type transformers was established as 30 C for 80 C average winding temperature rise. Since 1944, insulation temperature classes have increased to 220 C but IEEE standards continue to use a constant 30 C hottest spot temperature allowance. IEC standards use a variable hottest spot temperature allowance from 5 to 30 C. Six full size test windings were manufactured with imbedded thermocouples and 133 test runs performed to obtain temperature rise data. The test data indicated that the hottest spot temperature allowance used in IEEE standards for ventilated dry type transformers above 500 kVA is too low. This is due to the large thermal gradient from the bottom to the top of the windings caused by natural convection air flow through the cooling ducts. A constant ratio of hottest spot winding temperature rise to average winding temperature rise should be used in product standards for all insulation temperature classes. A ratio of 1.5 is suggested for ventilated dry type transformers above 500 kVA. This would increase the hottest spot temperature allowance from 30 C to 60 C and decrease the permissible average winding temperature rise from 150 C to 120 C for the 220 C insulation temperature class.

Pierce, L.W. (General Electric Co., Rome, GA (United States))

1994-01-01T23:59:59.000Z

39

Wall and laser spot motion in cylindrical hohlraums  

SciTech Connect (OSTI)

Wall and laser spot motion measurements in empty, propane-filled and plastic (CH)-lined gold coated cylindrical hohlraums were performed on the Omega laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. Wall motion was measured using axial two-dimensional (2D) x-ray imaging and laser spot motion was perpendicularly observed through a thinned wall using streaked hard x-ray imaging. Experimental results and 2D hydrodynamic simulations show that while empty targets exhibit on-axis plasma collision, CH-lined and propane-filled targets inhibit wall expansion, corroborated with perpendicular streaked imaging showing a slower motion of laser spots.

Huser, G.; Courtois, C.; Monteil, M.-C. [CEA, DAM, DIF, F-91297 Arpajon (France)

2009-03-15T23:59:59.000Z

40

On the burn topology of hot-spot-initiated reactions  

SciTech Connect (OSTI)

We determine the reaction progress function for an ideal hot spot model problem. The considered problem has an exact analytic solution that can derived from a reduction of Nichols statistical hot spot model. We perform numerical calculations to verify the analytic solution and to illustrate the error realized in real, finite systems. We show how the baseline problem, which does not distinguish between the reactant and product densities, can be scaled to handle general cases for which the two densities differ.

Hill, Larry G [Los Alamos National Laboratory; Zimmermann, Bjorn [WOLFRAM RESEARCH INC.; Nichols, Albert L [LLNL

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

The MC21 Monte Carlo Transport Code  

SciTech Connect (OSTI)

MC21 is a new Monte Carlo neutron and photon transport code currently under joint development at the Knolls Atomic Power Laboratory and the Bettis Atomic Power Laboratory. MC21 is the Monte Carlo transport kernel of the broader Common Monte Carlo Design Tool (CMCDT), which is also currently under development. The vision for CMCDT is to provide an automated, computer-aided modeling and post-processing environment integrated with a Monte Carlo solver that is optimized for reactor analysis. CMCDT represents a strategy to push the Monte Carlo method beyond its traditional role as a benchmarking tool or ''tool of last resort'' and into a dominant design role. This paper describes various aspects of the code, including the neutron physics and nuclear data treatments, the geometry representation, and the tally and depletion capabilities.

Sutton TM, Donovan TJ, Trumbull TH, Dobreff PS, Caro E, Griesheimer DP, Tyburski LJ, Carpenter DC, Joo H

2007-01-09T23:59:59.000Z

42

Butane segregated by fluorides, olefins content at Texas terminals  

SciTech Connect (OSTI)

Texas Eastern Products Pipeline Co., Houston (Teppco), this month has begun segregating butane streams at the company's Mont Belvieu and Baytown, Texas terminals according to fluoride and olefin contents. Streams containing fluoride or an olefin content greater than 1 ppm (or both) currently flow into Teppco's south Mont Belvieu terminal. Those fluoride-free streams with less than 1 ppm of olefins flow to its north Mont Belvieu terminal. Butane processed through an isomerization unit yields isobutane, a key component in MTBE. But high-fluoride butane from crude-oil refineries using hydrofluoric (HF) acid alkylation units cannot be used to produce MTBE because fluoride will damage isomerization units' process catalysts. Olefins also affect the efficiency of isomerization units, but less critically than fluorides. Their presence is higher in refinery product than in fractionated NGL. To extend the life of their process catalysts and to maximize yields, producers (including MTBE and isomerization unit operators) are specifying low-fluoride butanes developed from natural-gas fractionators or from refineries that do not use an HF process.

Not Available

1993-03-22T23:59:59.000Z

43

Friction Stir Spot Welding of DP780 Carbon Steel  

SciTech Connect (OSTI)

Friction stir spot welds were made in uncoated and galvannealed DP780 sheets using polycrystalline boron nitride stir tools. The tools were plunged at either a single continuous rate or in two segments consisting of a relatively high rate followed by a slower rate of shorter depth. Welding times ranged from 1 to 10 s. Increasing tool rotation speed from 800 to 1600 rev min{sup -1} increased strength values. The 2-segment welding procedures also produced higher strength joints. Average lap shear strengths exceeding 10 {center_dot} 3 kN were consistently obtained in 4 s on both the uncoated and the galvannealed DP780. The likelihood of diffusion and mechanical interlocking contributing to bond formation was supported by metallographic examinations. A cost analysis based on spot welding in automobile assembly showed that for friction stir spot welding to be economically competitive with resistance spot welding the cost of stir tools must approach that of resistance spot welding electrode tips.

Santella, Michael L [ORNL; Hovanski, Yuri [ORNL; Frederick, David Alan [ORNL; Grant, Glenn J [ORNL; Dahl, Michael E [ORNL

2010-01-01T23:59:59.000Z

44

Predicting hottest spot temperatures in ventilated dry type transformer windings  

SciTech Connect (OSTI)

Test data indicates that hottest spot allowances used in IEEE standards for ventilated dry type transformers above 500 kVA are too low. A mathematical model to predict hottest spot temperature rises in ventilated dry type transformers was developed. Data from six layer type test windings and a 2500 kva prototype was used to refine the model. A correlation for the local heat transfer coefficient in the cooling ducts was developed. The model was used to study the effect of various parameters on the ratio of hottest spot to average winding temperature rise. The number of conductor layers, insulation thickness, and conductor strand size were found to have only a minor effect on the ratio. Winding height was found to be the main parameter influencing the ratio of hottest spot to average winding temperature rise. The study based on the mathematical model confirmed previous conclusions based on test data that the hottest spot allowances used in IEEE standards for ventilated dry type transformers above 500 kVA should be revised.

Pierce, L.W. (General Electric Co., Rome, GA (United States))

1994-04-01T23:59:59.000Z

45

THE BEGINNING of the MONTE CARLO METHOD  

E-Print Network [OSTI]

. For a whole host of 125 #12;Monte Carlo reasons, he had become seriously inter- ested in the thermonuclear a preliminary computational model of a thermonuclear reaction for the ENIAC. He felt he could convince

46

Monte Carlo simulation in systems biology  

E-Print Network [OSTI]

2 The history of Monte Carlo Sampling in Systems Biology 1.1simulation tools: the systems biology workbench and biospiceCellular and Molecular Biology. ASM Press, Washington

Schellenberger, Jan

2010-01-01T23:59:59.000Z

47

Exponential convergence with adaptive Monte Carlo  

SciTech Connect (OSTI)

For over a decade, it has been known that exponential convergence on discrete transport problems was possible using adaptive Monte Carlo techniques. Now, exponential convergence has been empirically demonstrated on a spatially continuous problem.

Booth, T.E.

1997-11-01T23:59:59.000Z

48

Io hot spots - infrared photometry of satellite occultations  

SciTech Connect (OSTI)

Io's active hot spots, which are presently mapped on the basis of IR photometry of this moon's occultation by other Gallilean satellites, are obtained with greatest spatial resolution near the sub-earth point. A model is developed for the occultation lightcurves, and its fitting to the data defines the apparent path of the occulting satellite relative to Io; the mean error in apparent relative position of occulting satellites is of the order of 178 km. A heretofore unknown, 20-km diameter hot spot is noted on Io's leading hemisphere. 31 references.

Goguen, J.D.; Matson, D.L.; Sinton, W.M.; Howell, R.R.; Dyck, H.M.

1988-12-01T23:59:59.000Z

49

The role of Monte Carlo within a diagonalization/Monte Carlo scheme  

E-Print Network [OSTI]

We review the method of stochastic error correction which eliminates the truncation error associated with any subspace diagonalization. Monte Carlo sampling is used to compute the contribution of the remaining basis vectors not included in the initial diagonalization. The method is part of a new approach to computational quantum physics which combines both diagonalization and Monte Carlo techniques.

Dean Lee

2000-10-31T23:59:59.000Z

50

Minimum-Hot-Spot Query Trees for Wireless Sensor Networks  

E-Print Network [OSTI]

an energy- efficient query routing tree. (a) Energy harvesting for battery- less nodes for the (b) Voltree to the querying node. Energy-efficient query routing trees are needed in a plethora of systems such as PeopleMinimum-Hot-Spot Query Trees for Wireless Sensor Networks Georgios Chatzimilioudis Dept

Zeinalipour, Demetris

51

REAL TIME ULTRASONIC ALUMINUM SPOT WELD MONITORING SYSTEM  

SciTech Connect (OSTI)

Aluminum alloys pose several properties that make them one of the most popular engineering materials: they have excellent corrosion resistance, and high weight-to-strength ratio. Resistance spot welding of aluminum alloys is widely used today but oxide film and aluminum thermal and electrical properties make spot welding a difficult task. Electrode degradation due to pitting, alloying and mushrooming decreases the weld quality and adjustment of parameters like current and force is required. To realize these adjustments and ensure weld quality, a tool to measure weld quality in real time is required. In this paper, a real time ultrasonic non-destructive evaluation system for aluminum spot welds is presented. The system is able to monitor nugget growth while the spot weld is being made. This is achieved by interpreting the echoes of an ultrasound transducer located in one of the welding electrodes. The transducer receives and transmits an ultrasound signal at different times during the welding cycle. Valuable information of the weld quality is embedded in this signal. The system is able to determine the weld nugget diameter by measuring the delays of the ultrasound signals received during the complete welding cycle. The article presents the system performance on aluminum alloy AA6022.

Regalado, W. Perez; Chertov, A. M.; Maev, R. Gr. [Institute for Diagnostic Imaging Research, Physics Department, University of Windsor, 292 Essex Hall, 401 Sunset Ave. N9B 3P4 Windsor, Ontario (Canada)

2010-02-22T23:59:59.000Z

52

Spot Convenience Yield Models for Energy Michael Ludkovski  

E-Print Network [OSTI]

. This is not true for some commodities, such as electricity. Even for mature markets like crude oil where spot of fu- ture asset and current consumption values. However, unlike financial deriva- tives, storage, the agent has the option of flexibility with regards to consumption (no risk of commodity shortage

Ludkovski, Mike

53

Front Vehicle Blind Spot Translucentization Based on Augmented Reality  

E-Print Network [OSTI]

Front Vehicle Blind Spot Translucentization Based on Augmented Reality Che-Tsung Lin, Yu-Chen Lin--Recently, WAVE/DSRC has become an attrac- tive technology for vehicular safety applications. Vehicles with WAVE/DSRC devices can communicate with their neighboring vehicles to exchange information to achieve collaborative

Wang, Yuan-Fang

54

Bright Spots in the South Carolina the Economy  

E-Print Network [OSTI]

Bright Spots in the South Carolina the Economy 2012 African American Economic Summit Doug Woodward Professor of Economics #12;Overview · Why we should worry. ­ Global economy and financial contagion. ­ U.S. economy and political uncertainty. · Why we should be happy. ­ South Carolina economy healing. · Robust

Almor, Amit

55

Spot welding of steel and aluminum using insert sheet  

SciTech Connect (OSTI)

Automobile industries have been increasingly interested in the use of aluminum and thus joining of steel and aluminum becomes of importance. The joining of the two types of metal raises a problem of brittle welds caused by the formation of intermetallic compounds. The authors solved the problem by using an insert sheet. This paper deals with the resistance spot welding of steel and aluminum sheets using insert sheets. The insert sheet used in the present development was a steel/aluminum clad sheet of the 0.8 mm thickness with 50% steel and 50% aluminum. The clad sheet was produced by warm rolling of steel and aluminum with a direct resistance heating process. Steel to be warm rolled was of EDDQ of the 0.4 mm thickness and aluminum was of JIS A1050 of 0.6 mm thickness. The mechanical properties of the insert clad sheets were in between those of the steel sheets and the aluminum sheets, while the clad sheets showed much better formability than the aluminum sheets. Resistance spot welding was conducted for 0.8 mm thick EDDQ steel sheets and 1.0 mm thick aluminum alloy (AL-5.5%Mg) sheets under the welding force of 1.96 kN, welding current ranging between 4.2 and 20.1 kA, and welding time from 0.5 to 10 cycles. The steel was spot welded to the steel side of the insert sheet while the aluminum was welded to the aluminum side. What the authors investigated were the applicable welding current range, nugget diameter, tensile shear strength, U-tension strength, and macro- and microstructures. In conclusion, steel sheets can be spot welded to aluminum sheets without difficulty by using clad sheets as insert materials while the strength level of the dissimilar metal spot welds is close to that of aluminum joints.

Oikawa, H.; Saito, T.; Yoshimura, T. [and others

1994-12-31T23:59:59.000Z

56

E-Print Network 3.0 - anti-white spot syndrome Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

white spot syndrome Search Powered by Explorit Topic List Advanced Search Sample search results for: anti-white spot syndrome Page: << < 1 2 3 4 5 > >> 1 JOURNAL OF VIROLOGY, June...

57

EGG AND LARVAL DEVELOPMENT OF THE SPOT, LEIOSTOMUS XANTHURUS (SCIAENIDAE)l  

E-Print Network [OSTI]

Atlantic and GulfofMexico coasts from Massachusetts Bay to the Bay of Campeche (Johnson 1978). Spot spawns

58

Time series analysis and long range correlations of Nordic spot electricity market  

E-Print Network [OSTI]

, 21020 Ispra(VA), Italy Abstract The electricity system price of the Nord Pool spot market is analysed. Weron and Przybylowicz [19] studied the electricity prices using Hurst R/S analysis and showed anti energy spot price time series. The question of modelling electricity spot prices has also been addressed

Wright, Francis

59

A k-factor GIGARCH process: Estimation and Application on electricity market spot prices.  

E-Print Network [OSTI]

A k-factor GIGARCH process: Estimation and Application on electricity market spot prices. Abdou Kâ time series of market data, such as electricity spot price, exhibit long-memory, in the sense of slowly this approach to electricity prices (spot prices) from the German energy market (European Energy e

Paris-Sud XI, Université de

60

IMPROVING MULTI-LATTICE ALIGNMENT BASED SPOKEN KEYWORD SPOTTING Hui Lin, Alex Stupakov and Jeff Bilmes  

E-Print Network [OSTI]

, such as when- ever it is inconvenient, unsafe, or impossible for the user to enter a search query using and the utterance being searched is beneficial for spoken keyword spotting. In this paper, we introduce several im- prove the performance of spoken keyword spotting. Index Terms-- Spoken keyword spotting, lattice

Noble, William Stafford

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Delivery and Hedging Delivery ties the futures price to the spot price.  

E-Print Network [OSTI]

Delivery and Hedging · Delivery ties the futures price to the spot price. · On the delivery date, the settlement price of the futures contract is determined by the spot price. · Hence, when the delivery period is reached, the futures price should be very close to the spot price. · Changes in futures prices usually

Lyuu, Yuh-Dauh

62

The NordPool Market The spot and electricity forward relation  

E-Print Network [OSTI]

The NordPool Market The spot and electricity forward relation Spot price modelling HJM approach to forwards Conclusions Modelling and pricing in electricity markets Fred Espen Benth Work in collaboration and electricity forward relation Spot price modelling HJM approach to forwards Conclusions Overview

Pfeifer, Holger

63

Impulsive Spot Heating and Thermal Explosion of Interstellar Grains Revisited  

E-Print Network [OSTI]

The problem of impulsive heating of dust grains in cold, dense interstellar clouds is revisited theoretically, with the aim to better understand leading mechanisms of the explosive desorption of icy mantles. It is rigorously shown that if the heating of a reactive medium occurs within a sufficiently localized spot (e.g., heating of mantles by cosmic rays), then the subsequent thermal evolution is characterized by a single dimensionless number $\\lambda$. This number identifies a bifurcation between two distinct regimes: When $\\lambda$ exceeds a critical value (threshold), the heat equation exhibits the explosive solution, i.e., the thermal (chemical) explosion is triggered. Otherwise, thermal diffusion causes the deposited heat to spread over the entire grain -- this regime is commonly known as the whole-grain heating. The theory allows us to find a critical combination of the physical parameters that govern the explosion of icy mantles due to impulsive spot heating. In particular, the calculations suggest tha...

Ivlev, A V; Vasyunin, A; Caselli, P

2015-01-01T23:59:59.000Z

64

Monte Carlo Tools for Jet Quenching  

E-Print Network [OSTI]

A thorough understanding of jet quenching on the basis of multi-particle final states and jet observables requires new theoretical tools. This talk summarises the status and propects of the theoretical description of jet quenching in terms of Monte Carlo generators.

Korinna Zapp

2011-09-07T23:59:59.000Z

65

anatomy monte carlo: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

22 23 24 25 Next Page Last Page Topic Index 1 Optical Monte Carlo modeling of a true port wine stain anatomy Biology and Medicine Websites Summary: Optical Monte Carlo modeling of...

66

X-ray focal spot locating apparatus and method  

DOE Patents [OSTI]

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Gilbert, Hubert W. (Cedar Crest, NM)

1985-07-30T23:59:59.000Z

67

A statistical study of bright spot reflection parameters  

E-Print Network [OSTI]

cal Study of Bright Spot Reflection Parameters. (December 1981) David Lee Godwin, B. S. , Pepperdine University Chairman of Adv1sory Committee: Dr. T. W. Spencer A data set consisting of two seismic lines served as the basis of study... obtained from each of the seismic lines were compared to deter- mine if the presence of commercial quantities of gas could be identified. The measurement process revealed that the interval travel time measurements between the marker horizons...

Godwin, David Lee

1981-01-01T23:59:59.000Z

68

Evidence of randomness in United States spot oil prices  

SciTech Connect (OSTI)

This study investigates U.S. crude oil spot-market prices to determine if they were cyclical, autoregressive, or random in nature. The fact that oil-price volatility emerged only with the rise of spot markets meant that data for this type of an analysis were not previously available. The hypothesis tested was that U.S. crude oil price changes are neither cyclical nor autocorrelated, and are, therefore, random. Daily data on U.S. crude oil spot market prices (for the period of December 3, 1984 to November 4, 1988) were analyzed using spectral analysis; this converts time-series data into a frequency series, where it can be analyzed using more-powerful statistical methods. The spectral results of the price series gave a maximum power spectrum of 0.026, which is considerably smaller than the significance level of 0.052, considered acceptable using a 99% confidence level. The conclusion reached was that there was no significant cyclicality or autocorrelation in the data. This indicated that the U.S. crude oil prices are efficient, and that it would not be possible to predict crude oil price changes by using historical price data, seasonality, or business cycles.

Howard, B.W.

1989-01-01T23:59:59.000Z

69

MONTE CARLO CALCULATIONS OF LR115 DETECTOR RESPONSE TO 222  

E-Print Network [OSTI]

(4):414­419; 2000 Key words: Monte Carlo; radon progeny; detector, alpha- track; thoron INTRODUCTION THE LR115

Yu, K.N.

70

Module 2: Monte Carlo Methods Prof. Mike Giles  

E-Print Network [OSTI]

, Bermudan options, optimal trading given transaction costs) MC Lecture 1 ­ p. 7 #12;Monte Carlo vs. finite 1 ­ p. 5 #12;Monte Carlo vs. finite differences Hard to get reliable figures, but my "guesstimate most heavily? . . . and will it stay that way in the future? MC Lecture 1 ­ p. 6 #12;Monte Carlo vs

Giles, Mike

71

John von Neumann Institute for Computing Monte Carlo Protein Folding  

E-Print Network [OSTI]

John von Neumann Institute for Computing Monte Carlo Protein Folding: Simulations of Met://www.fz-juelich.de/nic-series/volume20 #12;#12;Monte Carlo Protein Folding: Simulations of Met-Enkephalin with Solvent-Accessible Area difficulties in applying Monte Carlo methods to protein folding. The solvent-accessible area method, a popular

Hsu, Hsiao-Ping

72

Multiple Overlapping Tiles for Contextual Monte Carlo Tree Search  

E-Print Network [OSTI]

for linear transforms [4] or active learning [8]. The use of Monte Carlo simulations to evaluate a situation- tions depending on the context. The modification is based on a reward function learned on a tiling of the space of Monte Carlo simulations. The tiling is done by regrouping the Monte Carlo simulations where two

73

Understanding plastic deformation in thermal glasses from single-soft-spot dynamics  

E-Print Network [OSTI]

By considering the low-frequency vibrational modes of amorphous solids, Manning and Liu [Phys. Rev. Lett. 107, 108302 (2011)] showed that a population of "soft spots" can be identified that are intimately related to plasticity at zero temperature under quasistatic shear. In this work we track individual soft spots with time in a two-dimensional sheared thermal Lennard Jones glass at temperatures ranging from deep in the glassy regime to above the glass transition temperature. We show that the lifetimes of individual soft spots are correlated with the timescale for structural relaxation. We additionally calculate the number of rearrangements required to destroy soft spots, and show that most soft spots can survive many rearrangements. Finally, we show that soft spots are robust predictors of rearrangements at temperatures well into the super-cooled regime. Altogether, these results pave the way for mesoscopic theories of plasticity of amorphous solids based on dynamical behavior of individual soft spots.

Samuel S. Schoenholz; Andrea J. Liu; Robert A. Riggleman; Joerg Rottler

2014-04-04T23:59:59.000Z

74

Single-shot and single-spot measurement of laser ablation threshold for carbon nanotubes  

E-Print Network [OSTI]

A simple and convenient procedure for single-shot, single-spot ablation threshold measurement has been developed. It is based on the employment of cylindrical lens to obtain elliptical Gaussian laser spot. The ablated spot chords which are parallel to the minor axis were measured across the spot major axis which is proportional to the fluence cross-section thus providing wide range dependence of damaged spot size versus fluence in one spot measurement. For both conventional and new-developed procedures the ablation threshold for typical Nd:YAG laser parameters (1064 nm, 10 ns) has been measured as 50 mJ/cm2 which is one order of magnitude lower than that for a bulk graphite.

Lednev, Vasily N; Obraztsova, Elena D; Kudryashov, Sergey I; Bunkin, Alexey F

2013-01-01T23:59:59.000Z

75

Guideline of Monte Carlo calculation. Neutron/gamma ray transport simulation by Monte Carlo method  

E-Print Network [OSTI]

This report condenses basic theories and advanced applications of neutron/gamma ray transport calculations in many fields of nuclear energy research. Chapters 1 through 5 treat historical progress of Monte Carlo methods, general issues of variance reduction technique, cross section libraries used in continuous energy Monte Carlo codes. In chapter 6, the following issues are discussed: fusion benchmark experiments, design of ITER, experiment analyses of fast critical assembly, core analyses of JMTR, simulation of pulsed neutron experiment, core analyses of HTTR, duct streaming calculations, bulk shielding calculations, neutron/gamma ray transport calculations of the Hiroshima atomic bomb. Chapters 8 and 9 treat function enhancements of MCNP and MVP codes, and a parallel processing of Monte Carlo calculation, respectively. An important references are attached at the end of this report.

2002-01-01T23:59:59.000Z

76

Hot spot-derived shock initiation phenomena in heterogeneous nitromethane  

SciTech Connect (OSTI)

The addition of solid silica particles to gelled nitromethane offers a tractable model system for interrogating the role of impedance mismatches as one type of hot spot 'seed' on the initiation behaviors of explosive formulations. Gas gun-driven plate impact experiments are used to produce well-defined shock inputs into nitromethane-silica mixtures containing size-selected silica beads at 6 wt%. The Pop-plots or relationships between shock input pressure and rundistance (or time)-to-detonation for mixtures containing small (1-4 {micro}m) and large (40 {micro}m) beads are presented. Overall, the addition of beads was found to influence the shock sensitivity of the mixtures, with the smaller beads being more sensitizing than the larger beads, lowering the shock initiation threshold for the same run distance to detonation compared with neat nitromethane. In addition, the use of embedded electromagnetic gauges provides detailed information pertaining to the mechanism of the build-up to detonation and associated reactive flow. Of note, an initiation mechanism characteristic of homogeneous liquid explosives, such as nitromethane, was observed in the nitromethane-40 {micro}m diameter silica samples at high shock input pressures, indicating that the influence of hot spots on the initiation process was minimal under these conditions.

Dattelbaum, Dana M [Los Alamos National Laboratory; Sheffield, Stephen A [Los Alamos National Laboratory; Stahl, David B [Los Alamos National Laboratory; Dattelbaum, Andrew M [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

77

The magnetic configuration of a delta-spot  

E-Print Network [OSTI]

Sunspots, which harbor both magnetic polarities within one penumbra, are called delta-spots. They are often associated with flares. Nevertheless, there are only very few detailed observations of the spatially resolved magnetic field configuration. We present an investigation performed with the Tenerife Infrared Polarimeter at the Vacuum Tower Telescope in Tenerife. We observed a sunspot with a main umbra and several additional umbral cores, one of them with opposite magnetic polarity (the delta-umbra). The delta-spot is divided into two parts by a line along which central emissions of the spectral line Ca II 854.2 nm appear. The Evershed flow comming from the main umbra ends at this line. In deep photospheric layers, we find an almost vertical magnetic field for the delta-umbra, and the magnetic field decreases rapidly with height, faster than in the main umbra. The horizontal magnetic field in the direction connecting main and delta-umbra is rather smooth, but in one location next to a bright penumbral featu...

Balthasar, Horst; Louis, Rohan E; Verma, Meetu; Denker, Carsten

2013-01-01T23:59:59.000Z

78

March market review. [Spot market prices for uranium (1993)  

SciTech Connect (OSTI)

The spot market price for uranium in unrestricted markets weakened further during March, and at month end, the NUEXCO Exchange Value had fallen $0.15, to $7.45 per pound U3O8. The Restricted American Market Penalty (RAMP) for concentrates increased $0.15, to $2.55 per pound U3O8. Ample UF6 supplies and limited demand led to a $0.50 decrease in the UF6 Value, to $25.00 per kgU as UF6, while the RAMP for UF6 increased $0.75, to $5.25 per kgU. Nine near-term uranium transactions were reported, totalling almost 3.3 million pounds equivalent U3O8. This is the largest monthly spot market volume since October 1992, and is double the volume reported in January and February. The March 31 Conversion Value was $4.25 per kgU as UF6. Beginning with the March 31 Value, NUEXCO now reports its Conversion Value in US dollars per kilogram of uranium (US$/kgU), reflecting current industry practice. The March loan market was inactive with no transactions reported. The Loan Rate remained unchanged at 3.0 percent per annum. Low demand and increased competition among sellers led to a one-dollar decrease in the SWU Value, to $65 per SWU, and the RAMP for SWU declined one dollar, to $9 per SWU.

Not Available

1993-04-01T23:59:59.000Z

79

Host-specific strain of Stemphylium causes leaf spot disease of California spinach  

E-Print Network [OSTI]

spinach culti- vars developed leaf spots within 2 weeks, while the wateras onto spinach lines used in downy mildew research. A water

Koike, Steven T.; Henderson, Diana M.; Butler, Edward E.

2001-01-01T23:59:59.000Z

80

Optimal spot market inventory strategies in the presence of cost and price risk  

E-Print Network [OSTI]

Optimal spot market inventory strategies in the presence ofeither increase or decrease inventory by buying or sellingof actively managing inventory during the period rather than

Guo, X.; Kaminsky, P.; Tomecek, P.; Yuen, M.

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Transformation from spots to waves in a model of actin pattern formation  

E-Print Network [OSTI]

Actin networks in certain single-celled organisms exhibit a complex pattern-forming dynamics that starts with the appearance of static spots of actin on the cell cortex. Spots soon become mobile, executing persistent random walks, and eventually give rise to traveling waves of actin. Here we describe a possible physical mechanism for this distinctive set of dynamic transformations, by equipping an excitable reaction-diffusion model with a field describing the spatial orientation of its chief constituent (which we consider to be actin). The interplay of anisotropic actin growth and spatial inhibition drives a transformation at fixed parameter values from static spots to moving spots to waves.

Stephen Whitelam; Till Bretschneider; Nigel J. Burroughs

2009-05-18T23:59:59.000Z

82

A Monte Carlo algorithm for degenerate plasmas  

SciTech Connect (OSTI)

A procedure for performing Monte Carlo calculations of plasmas with an arbitrary level of degeneracy is outlined. It has possible applications in inertial confinement fusion and astrophysics. Degenerate particles are initialised according to the Fermi–Dirac distribution function, and scattering is via a Pauli blocked binary collision approximation. The algorithm is tested against degenerate electron–ion equilibration, and the degenerate resistivity transport coefficient from unmagnetised first order transport theory. The code is applied to the cold fuel shell and alpha particle equilibration problem of inertial confinement fusion.

Turrell, A.E., E-mail: a.turrell09@imperial.ac.uk; Sherlock, M.; Rose, S.J.

2013-09-15T23:59:59.000Z

83

Monte Carlo simulations on Graphics Processing Units  

E-Print Network [OSTI]

Implementation of basic local Monte-Carlo algorithms on ATI Graphics Processing Units (GPU) is investigated. The Ising model and pure SU(2) gluodynamics simulations are realized with the Compute Abstraction Layer (CAL) of ATI Stream environment using the Metropolis and the heat-bath algorithms, respectively. We present an analysis of both CAL programming model and the efficiency of the corresponding simulation algorithms on GPU. In particular, the significant performance speed-up of these algorithms in comparison with serial execution is observed.

Vadim Demchik; Alexei Strelchenko

2009-03-30T23:59:59.000Z

84

Quantum Monte Carlo calculations for light nuclei  

SciTech Connect (OSTI)

Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 30 different (j{sup {prime}}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.

Wiringa, R.B.

1998-08-01T23:59:59.000Z

85

Mont Vista Capital LLC | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to:Moe WindMont Vista Capital LLC Place: New

86

Energy Monte Carlo (EMCEE) | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision has beenFfe2fb55-352f-473b-a2dd-50ae8b27f0a6 No revisionWind,SoilsfilesystemEvents UKSPARQLIncMonte Carlo

87

Eolica Montes de Cierzo | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of Inspector GeneralDepartmentAUDIT REPORTOpen Energy Information EnergySolar Systems JumpEolicaMontes de

88

aux propositions Monte Verit Le Congressi Stefano Franscini, plate-  

E-Print Network [OSTI]

Appel aux propositions Monte Verità Le Congressi Stefano Franscini, plate- forme de congrès de l'Ecole polytechnique fédérale de Zurich, offre la possibilité d'or- ganiser des conférences de recherche au Monte senior et junior, séjournant au Monte Verità pendant toute la durée de la conférence Le formulaire de

Richner, Heinz

89

Monte Carlo Simulations of the Corrosion of Aluminoborosilicate...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Corrosion of Aluminoborosilicate Glasses. Monte Carlo Simulations of the Corrosion of Aluminoborosilicate Glasses. Abstract: Aluminum is one of the most common components included...

90

Light stops, blind spots, and isospin violation in the MSSM  

E-Print Network [OSTI]

In the framework of the MSSM, we examine several simplified models where only a few superpartners are light. This allows us to study WIMP-nucleus scattering in terms of a handful of MSSM parameters and thereby scrutinize their impact on dark matter direct-detection experiments. Focusing on spin-independent WIMP-nucleon scattering, we derive simplified, analytic expressions for the Wilson coefficients associated with Higgs and squark exchange. We utilize these results to study the complementarity of constraints due to direct-detection, flavor, and collider experiments. We also identify parameter configurations that produce (almost) vanishing cross sections. In the proximity of these so-called blind spots, the amount of isospin violation is found to be much larger than typically expected in the MSSM. This feature is a generic property of parameter regions where cross sections are suppressed, and highlights the importance of a careful analysis of the nucleon couplings and the associated hadronic uncertainties. T...

Crivellin, Andreas; Procura, Massimiliano; Tunstall, Lewis C

2015-01-01T23:59:59.000Z

91

Quantum Monte Carlo methods for nuclear physics  

E-Print Network [OSTI]

Quantum Monte Carlo methods have proved very valuable to study the structure and reactions of light nuclei and nucleonic matter starting from realistic nuclear interactions and currents. These ab-initio calculations reproduce many low-lying states and transition moments in light nuclei, and simultaneously predict many properties of light nuclei and neutron matter over a rather wide range of energy and momenta. We review the nuclear interactions and currents, and describe the continuum Quantum Monte Carlo methods used in nuclear physics. These methods are similar to those used in condensed matter and electronic structure but naturally include spin-isospin, tensor, spin-orbit, and three-body interactions. We present a variety of results including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. We also describe low-energy scattering techniques, studies of the electroweak response of nuclei relevant in electron and neutrino scattering, and the properties of dense nucleonic matter as found in neutron stars. A coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.

J. Carlson; S. Gandolfi; F. Pederiva; Steven C. Pieper; R. Schiavilla; K. E. Schmidt; R. B. Wiringa

2014-12-09T23:59:59.000Z

92

THE MCNPX MONTE CARLO RADIATION TRANSPORT CODE  

SciTech Connect (OSTI)

MCNPX (Monte Carlo N-Particle eXtended) is a general-purpose Monte Carlo radiation transport code with three-dimensional geometry and continuous-energy transport of 34 particles and light ions. It contains flexible source and tally options, interactive graphics, and support for both sequential and multi-processing computer platforms. MCNPX is based on MCNP4B, and has been upgraded to most MCNP5 capabilities. MCNP is a highly stable code tracking neutrons, photons and electrons, and using evaluated nuclear data libraries for low-energy interaction probabilities. MCNPX has extended this base to a comprehensive set of particles and light ions, with heavy ion transport in development. Models have been included to calculate interaction probabilities when libraries are not available. Recent additions focus on the time evolution of residual nuclei decay, allowing calculation of transmutation and delayed particle emission. MCNPX is now a code of great dynamic range, and the excellent neutronics capabilities allow new opportunities to simulate devices of interest to experimental particle physics; particularly calorimetry. This paper describes the capabilities of the current MCNPX version 2.6.C, and also discusses ongoing code development.

WATERS, LAURIE S. [Los Alamos National Laboratory; MCKINNEY, GREGG W. [Los Alamos National Laboratory; DURKEE, JOE W. [Los Alamos National Laboratory; FENSIN, MICHAEL L. [Los Alamos National Laboratory; JAMES, MICHAEL R. [Los Alamos National Laboratory; JOHNS, RUSSELL C. [Los Alamos National Laboratory; PELOWITZ, DENISE B. [Los Alamos National Laboratory

2007-01-10T23:59:59.000Z

93

A NON-GAUSSIAN ORNSTEIN-UHLENBECK PROCESS FOR ELECTRICITY SPOT PRICE MODELING AND  

E-Print Network [OSTI]

A NON-GAUSSIAN ORNSTEIN-UHLENBECK PROCESS FOR ELECTRICITY SPOT PRICE MODELING AND DERIVATIVES for analytical pricing of electricity forward and futures contracts. Electricity forward and futures contracts to capture the observed dynamics of electricity spot prices. We also discuss the pricing of European call

Kallsen, Jan

94

Resistance Spot Welding of Galvanized Steel: Part I. Material Variations and Process Modifications  

E-Print Network [OSTI]

( l Resistance Spot Welding of Galvanized Steel: Part I. Material Variations and Process to determine their effects on the acceptable range of resistance spot welding conditions for galvanized steel upsloping and downsloping of the weld current, preheat current, postheat current, electrode tip geometry

Eagar, Thomas W.

95

The Effects of the Dysfunctional Spot Market for Electricity in California  

E-Print Network [OSTI]

The Effects of the Dysfunctional Spot Market for Electricity in California on the Cost of Forward), the Consortium for Electric Reliability Technology Solutions (CERTS) program on Reliability and Markets at the U Cruz, California. #12;ABSTRACT The unexpectedly high spot prices for electricity in the summer of 2000

96

AUTOMATIC HOT SPOT DETECTION AND SEGMENTATION IN WHOLE BODY FDG-PET IMAGES Haiying Guan1  

E-Print Network [OSTI]

AUTOMATIC HOT SPOT DETECTION AND SEGMENTATION IN WHOLE BODY FDG-PET IMAGES Haiying Guan1 , Toshiro a system for automatic hot spots detection and segmentation in whole body FDG-PET images. The main in clinical PET images. 1.INTRODUCTION Positron emission tomography (PET) using fluorine-18 de- oxyglucose

California at Santa Barbara, University of

97

Direct and indirect effects of southern flounder predation on a spot population: Experimental and model analyses  

SciTech Connect (OSTI)

We have previously shown that southern flounder (Paralichthys lethostigma Jordan and Gilbert) influence the survival and size-distribution of spot (Leiostomus xanthurus Lafayette) and other small estuarine fishes in experimental ponds. In this paper, we seek to determine whether these of effects can be accounted for by direct size-dependent predation or if there is also evidence for indirect behavioral effects on spot foraging which might alter their survival or population size structure. In our experiment, spot were allowed to grow in the presence and absence of southern flounder in an experimental estuarine pond for 101 days. Each treatment was replicated three times. We also apply a recently published simulation model of the flounder-spot interaction to this experiment to independently test the model and to estimate the direct effects of flounder predation on spot survival and size structure.

Crowder, L.B.; Wright, R.A.; Martin, T.H.; Rice, J.A. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Zoology); Rose, K.A. (Oak Ridge National Lab., TN (United States))

1992-01-01T23:59:59.000Z

98

Direct and indirect effects of southern flounder predation on a spot population: Experimental and model analyses  

SciTech Connect (OSTI)

We have previously shown that southern flounder (Paralichthys lethostigma Jordan and Gilbert) influence the survival and size-distribution of spot (Leiostomus xanthurus Lafayette) and other small estuarine fishes in experimental ponds. In this paper, we seek to determine whether these of effects can be accounted for by direct size-dependent predation or if there is also evidence for indirect behavioral effects on spot foraging which might alter their survival or population size structure. In our experiment, spot were allowed to grow in the presence and absence of southern flounder in an experimental estuarine pond for 101 days. Each treatment was replicated three times. We also apply a recently published simulation model of the flounder-spot interaction to this experiment to independently test the model and to estimate the direct effects of flounder predation on spot survival and size structure.

Crowder, L.B.; Wright, R.A.; Martin, T.H.; Rice, J.A. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Zoology; Rose, K.A. [Oak Ridge National Lab., TN (United States)

1992-12-31T23:59:59.000Z

99

RADIATIVE HEAT TRANSFER WITH QUASI-MONTE CARLO METHODS  

E-Print Network [OSTI]

RADIATIVE HEAT TRANSFER WITH QUASI-MONTE CARLO METHODS A. Kersch1 W. Moroko2 A. Schuster1 1Siemens of Quasi-Monte Carlo to this problem. 1.1 Radiative Heat Transfer Reactors In the manufacturing of the problems which can be solved by such a simulation is high accuracy modeling of the radiative heat transfer

100

Adjoint electron-photon transport Monte Carlo calculations with ITS  

SciTech Connect (OSTI)

A general adjoint coupled electron-photon Monte Carlo code for solving the Boltzmann-Fokker-Planck equation has recently been created. It is a modified version of ITS 3.0, a coupled electronphoton Monte Carlo code that has world-wide distribution. The applicability of the new code to radiation-interaction problems of the type found in space environments is demonstrated.

Lorence, L.J.; Kensek, R.P.; Halbleib, J.A. [Sandia National Labs., Albuquerque, NM (United States); Morel, J.E. [Los Alamos National Lab., NM (United States)

1995-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

STORM in Monte Carlo reactor physics calculations KAUR TUTTELBERG  

E-Print Network [OSTI]

STORM in Monte Carlo reactor physics calculations KAUR TUTTELBERG Master of Science Thesis Carlo reactor physics criticality calculations. This is achieved by optimising the number of neutron for more efficient Monte Carlo reactor physics calculations, giving results with errors that can

Haviland, David

102

Special Topics Monte Carlo Methods in Science, Engineering and Business  

E-Print Network [OSTI]

SYLLABUS Special Topics ­ Monte Carlo Methods in Science, Engineering and Business Fall, 2007 in Probability and Statistics 3. Simple Simulation Methods 4. Sequential Monte Carlo Methods 5. Markov Chain up shortly Prerequisite: First Graduate Level Mathematical Statistics Course It should be emphasized

Shepp, Larry

103

CERN-TH.6275/91 Monte Carlo Event Generation  

E-Print Network [OSTI]

CERN-TH.6275/91 Monte Carlo Event Generation for LHC T. Sj¨ostrand CERN -- Geneva Abstract The necessity of event generators for LHC physics studies is illustrated, and the Monte Carlo approach is outlined. A survey is presented of existing event generators, followed by a more detailed study

Sjöstrand, Torbjörn

104

Monte Carlo stratified source-sampling  

SciTech Connect (OSTI)

In 1995, at a conference on criticality safety, a special session was devoted to the Monte Carlo {open_quotes}eigenvalue of the world{close_quotes} problem. Argonne presented a paper, at that session, in which the anomalies originally observed in that problem were reproduced in a much simplified model-problem configuration, and removed by a version of stratified source-sampling. The original test-problem was treated by a special code designed specifically for that purpose. Recently ANL started work on a method for dealing with more realistic eigenvalue of the world configurations, and has been incorporating this method into VIM. The original method has been modified to take into account real-world statistical noise sources not included in the model problem. This paper constitutes a status report on work still in progress.

Blomquist, R.N.; Gelbard, E.M.

1997-09-01T23:59:59.000Z

105

Quantum Ice : a quantum Monte Carlo study  

E-Print Network [OSTI]

Ice states, in which frustrated interactions lead to a macroscopic ground-state degeneracy, occur in water ice, in problems of frustrated charge order on the pyrochlore lattice, and in the family of rare-earth magnets collectively known as spin ice. Of particular interest at the moment are "quantum spin ice" materials, where large quantum fluctuations may permit tunnelling between a macroscopic number of different classical ground states. Here we use zero-temperature quantum Monte Carlo simulations to show how such tunnelling can lift the degeneracy of a spin or charge ice, stabilising a unique "quantum ice" ground state --- a quantum liquid with excitations described by the Maxwell action of 3+1-dimensional quantum electrodynamics. We further identify a competing ordered "squiggle" state, and show how both squiggle and quantum ice states might be distinguished in neutron scattering experiments on a spin ice material.

Nic Shannon; Olga Sikora; Frank Pollmann; Karlo Penc; Peter Fulde

2011-12-13T23:59:59.000Z

106

A hybrid Monte Carlo and response matrix Monte Carlo method in criticality calculation  

SciTech Connect (OSTI)

Full core calculations are very useful and important in reactor physics analysis, especially in computing the full core power distributions, optimizing the refueling strategies and analyzing the depletion of fuels. To reduce the computing time and accelerate the convergence, a method named Response Matrix Monte Carlo (RMMC) method based on analog Monte Carlo simulation was used to calculate the fixed source neutron transport problems in repeated structures. To make more accurate calculations, we put forward the RMMC method based on non-analog Monte Carlo simulation and investigate the way to use RMMC method in criticality calculations. Then a new hybrid RMMC and MC (RMMC+MC) method is put forward to solve the criticality problems with combined repeated and flexible geometries. This new RMMC+MC method, having the advantages of both MC method and RMMC method, can not only increase the efficiency of calculations, also simulate more complex geometries rather than repeated structures. Several 1-D numerical problems are constructed to test the new RMMC and RMMC+MC method. The results show that RMMC method and RMMC+MC method can efficiently reduce the computing time and variations in the calculations. Finally, the future research directions are mentioned and discussed at the end of this paper to make RMMC method and RMMC+MC method more powerful. (authors)

Li, Z.; Wang, K. [Dept. of Engineering Physics, Tsinghua Univ., Beijing, 100084 (China)

2012-07-01T23:59:59.000Z

107

An Analysis of Price Volatility in Different Spot Markets for Electricity in the U.S.A.  

E-Print Network [OSTI]

An Analysis of Price Volatility in Different Spot Markets for Electricity in the U.S.A. by Tim important feature. Spot prices for electricity have been very volatile with dramatic price spikes occurring insight into the behavior of spot prices for electricity, and in particular, to model the type

108

E-Print Network 3.0 - accelerating monte carlo Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of the Computational Cost of a Monte Carlo and Deterministic Algorithm for Summary: Comparison of the Computational Cost of a Monte Carlo and Deterministic Algorithm for...

109

E-Print Network 3.0 - accelerated monte carlo Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of the Computational Cost of a Monte Carlo and Deterministic Algorithm for Summary: Comparison of the Computational Cost of a Monte Carlo and Deterministic Algorithm for...

110

E-Print Network 3.0 - alloys monte carlo Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

to adjacent threefold sites according to the Metropolis Monte Carlo algorithm with the energy landscape from... by the displacement after 1000 Monte Carlo time steps. 16...

111

Accelerated rescaling of single Monte Carlo simulation runs with the Graphics Processing Unit (GPU)  

E-Print Network [OSTI]

and S. Andersson-Engels, “Accelerated Monte Carlo models toAccelerated rescaling of single Monte Carlo simulation runsreported on online, GPU- accelerated MC simulations. Along

Yang, Owen; Choi, Bernard

2013-01-01T23:59:59.000Z

112

Hot spot generation in energetic materials created by long-wavelength infrared radiation  

SciTech Connect (OSTI)

Hot spots produced by long-wavelength infrared (LWIR) radiation in an energetic material, crystalline RDX (1,3,5-trinitroperhydro-1,3,5-triazine), were studied by thermal-imaging microscopy. The LWIR source was a CO{sub 2} laser operating in the 28-30?THz range. Hot spot generation was studied using relatively low intensity (?100?W cm{sup ?2}), long-duration (450 ms) LWIR pulses. The hot spots could be produced repeatedly in individual RDX crystals, to investigate the fundamental mechanisms of hot spot generation by LWIR, since the peak hot-spot temperatures were kept to ?30?K above ambient. Hot spots were generated preferentially beneath RDX crystal planes making oblique angles with the LWIR beam. Surprisingly, hot spots were more prominent when the LWIR wavelength was tuned to be weakly absorbed (absorption depth ?30??m) than when the LWIR wavelength was strongly absorbed (absorption depth ?5??m). This unexpected effect was explained using a model that accounts for LWIR refraction and RDX thermal conduction. The weakly absorbed LWIR is slightly focused underneath the oblique crystal planes, and it penetrates the RDX crystals more deeply, increasing the likelihood of irradiating RDX defect inclusions that are able to strongly absorb or internally focus the LWIR beam.

Chen, Ming-Wei; You, Sizhu; Suslick, Kenneth S.; Dlott, Dana D., E-mail: dlott@illinois.edu [School of Chemical Sciences and Fredrick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2014-02-10T23:59:59.000Z

113

May market review. [Spot market prices for uranium (1993)  

SciTech Connect (OSTI)

Seven uranium transactions totalling nearly three million pounds equivalent U3O8 were reported during May, but only two, totalling less than 200 thousand pounds equivalent U3O8, involved concentrates. As no discretionary buying occurred during the month, and as near-term supply and demand were in relative balance, prices were steady, while both buyers and sellers appeared to be awaiting some new market development to signal the direction of future spot-market prices. The May 31, 1993, Exchange Value and the Restricted American market Penalty (RAMP) for concentrates were both unchanged at $7.10, and $2.95 per pound U3O8, respectively. NUEXCO's judgement was that transactions for significant quantities of uranium concentrates that were both deliverable in and intended for consumption in the USA could have been concluded on May 31 at $10.05 per pound U3O8. Two near-term concentrate transactions were reported in which one US utility purchased less than 200 thousand pounds equivalent U3O8 from two separate sellers. These sales occurred at price levels at or near the May 31 Exchange Value plus RAMP. No long-term uranium transactions were reported during May. Consequently, the UF6 Value decreased $0.20 to $24.30 per kgU as UF6, reflecting some weakening of the UF6 market outside the USA.

Not Available

1993-06-01T23:59:59.000Z

114

Light stops, blind spots, and isospin violation in the MSSM  

E-Print Network [OSTI]

In the framework of the MSSM, we examine several simplified models where only a few superpartners are light. This allows us to study WIMP-nucleus scattering in terms of a handful of MSSM parameters and thereby scrutinize their impact on dark matter direct-detection experiments. Focusing on spin-independent WIMP-nucleon scattering, we derive simplified, analytic expressions for the Wilson coefficients associated with Higgs and squark exchange. We utilize these results to study the complementarity of constraints due to direct-detection, flavor, and collider experiments. We also identify parameter configurations that produce (almost) vanishing cross sections. In the proximity of these so-called blind spots, the amount of isospin violation is found to be much larger than typically expected in the MSSM. This feature is a generic property of parameter regions where cross sections are suppressed, and highlights the importance of a careful analysis of the nucleon couplings and the associated hadronic uncertainties. This becomes especially relevant once the increased sensitivity of future direct-detection experiments corners the MSSM into these regions of parameter space.

Andreas Crivellin; Martin Hoferichter; Massimiliano Procura; Lewis C. Tunstall

2015-03-11T23:59:59.000Z

115

Iterative acceleration methods for Monte Carlo and deterministic criticality calculations  

SciTech Connect (OSTI)

If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors.

Urbatsch, T.J.

1995-11-01T23:59:59.000Z

116

Hawaiian hot-spot swell structure from seafloor MT sounding Steven Constablea,*, Graham Heinsonb,1  

E-Print Network [OSTI]

Hawaiian hot-spot swell structure from seafloor MT sounding Steven Constablea,*, Graham Heinsonb,1 5348090. E-mail addresses: sconstable@ucsd.edu (S. Constable)8 Graham.Heinson@adelaide.edu.au (G. Heinson

Constable, Steve

117

E-Print Network 3.0 - automatic robotic spotting Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: P2 position on the pig and the spot produced by the laser on the end of the robot arm. This was less... Computers and Electronics in Agriculture 44 (2004) 93-106 A...

118

Influence of spot size on propagation dynamics of laser-produced tin plasma  

E-Print Network [OSTI]

?Color online? Images of the tin plume recorded with 280 ? mdynamics of laser-produced tin plasma S. S. Harilal a?dynamics of an expanding tin plume for various spot sizes

Harilal, S S

2007-01-01T23:59:59.000Z

119

Calculation of the fast ion tail distribution for a spherically symmetric hot spot  

SciTech Connect (OSTI)

The fast ion tail for a spherically symmetric hot spot is computed via the solution of a simplified Fokker-Planck collision operator. Emphasis is placed on describing the energy scaling of the fast ion distribution function in the hot spot as well as the surrounding cold plasma throughout a broad range of collisionalities and temperatures. It is found that while the fast ion tail inside the hot spot is significantly depleted, leading to a reduction of the fusion yield in this region, a surplus of fast ions is observed in the neighboring cold plasma region. The presence of this surplus of fast ions in the neighboring cold region is shown to result in a partial recovery of the fusion yield lost in the hot spot.

McDevitt, C. J.; Tang, X.-Z.; Guo, Z. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Berk, H. L. [Department of Physics, University of Texas, Austin, Texas 78712 (United States)

2014-10-15T23:59:59.000Z

120

E-Print Network 3.0 - availability hot spot Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

20.00 2006 IEEE 22nd IEEE SEMI-THERM Symposium Hot Spot Cooling using Embedded Thermoelectric Coolers Summary: 0-7803-XXXX-X0620.00 2006 IEEE 22nd IEEE SEMI-THERM...

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Wetland monitoring using classification trees and SPOT-5 seasonal time series. Aurlie Davranche1  

E-Print Network [OSTI]

to estimate the area of4 marshes covered with common reeds (Phragmites australis) and submerged macrophytes5 Phragmites australis, remote sensing, SPOT-5, submerged macrophytes, wetland monitoring.29 30 1. Introduction

Paris-Sud XI, Université de

122

Reedbed monitoring using classification trees and SPOT-5 seasonal time series  

E-Print Network [OSTI]

, Phragmites australis, Remote sensing, SPOT-5. Abstract The Camargue, the RhĂ´ne river delta in south of France to model the presence of common reed (Phragmite australis) stands in Camargue. The development

Paris-Sud XI, Université de

123

Sequential Monte Carlo Methods for Protein Folding  

E-Print Network [OSTI]

We describe a class of growth algorithms for finding low energy states of heteropolymers. These polymers form toy models for proteins, and the hope is that similar methods will ultimately be useful for finding native states of real proteins from heuristic or a priori determined force fields. These algorithms share with standard Markov chain Monte Carlo methods that they generate Gibbs-Boltzmann distributions, but they are not based on the strategy that this distribution is obtained as stationary state of a suitably constructed Markov chain. Rather, they are based on growing the polymer by successively adding individual particles, guiding the growth towards configurations with lower energies, and using "population control" to eliminate bad configurations and increase the number of "good ones". This is not done via a breadth-first implementation as in genetic algorithms, but depth-first via recursive backtracking. As seen from various benchmark tests, the resulting algorithms are extremely efficient for lattice models, and are still competitive with other methods for simple off-lattice models.

Peter Grassberger

2004-08-26T23:59:59.000Z

124

April market review. [Spot market prices for uranium (1993)  

SciTech Connect (OSTI)

The spot market price for uranium outside the USA weakened further during April, and at month end, the NUEXCO Exchange Value had fallen $0.35, to $7.10 per pound U3O8. This is the lowest Exchange Value observed in nearly twenty years, comparable to Values recorded during the low price levels of the early 1970s. The Restricted American Market Penalty (RAMP) for concentrates increased $0.40, to $2.95 per pound U3O8. Transactions for significant quantities of uranium concentrates that are both deliverable in and intended for consumption in the USA could have been concluded on April 30 at $10.05 per pound U3O8, up $0.05 from the sum of corresponding March Values. Four near-term concentrates transactions were reported, totalling nearly 1.5 million pounds equivalent U3O8. One long-term sale was reported. The UF6 Value also declined, as increased competition among sellers led to a $0.50 decrease, to $24.50 per kgU as UF6. However, the RAMP for UF6 increased $0.65, to $5.90 per kgU as UF6, reflecting an effective US market level of $30.40 per kgU. Two near term transactions were reported totalling approximately 1.1 million pounds equivalent U3O8. In total, eight uranium transactions totalling 28 million pounds equivalent U3O8 were reported, which is about average for April market activity.

Not Available

1993-05-01T23:59:59.000Z

125

Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems  

SciTech Connect (OSTI)

Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absoption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

Nick Soelberg; Joe Enneking

2011-05-01T23:59:59.000Z

126

Enhancements in Continuous-Energy Monte Carlo Capabilities in SCALE  

SciTech Connect (OSTI)

Monte Carlo tools in SCALE are commonly used in criticality safety calculations as well as sensitivity and uncertainty analysis, depletion, and criticality alarm system analyses. Recent improvements in the continuous-energy data generated by the AMPX code system and significant advancements in the continuous-energy treatment in the KENO Monte Carlo eigenvalue codes facilitate the use of SCALE Monte Carlo codes to model geometrically complex systems with enhanced solution fidelity. The addition of continuous-energy treatment to the SCALE Monaco code, which can be used with automatic variance reduction in the hybrid MAVRIC sequence, provides significant enhancements, especially for criticality alarm system modeling. This paper describes some of the advancements in continuous-energy Monte Carlo codes within the SCALE code system.

Bekar, Kursat B [ORNL] [ORNL; Celik, Cihangir [ORNL] [ORNL; Wiarda, Dorothea [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Rearden, Bradley T [ORNL] [ORNL; Dunn, Michael E [ORNL] [ORNL

2013-01-01T23:59:59.000Z

127

Variance Reduction Techniques for Implicit Monte Carlo Simulations  

E-Print Network [OSTI]

The Implicit Monte Carlo (IMC) method is widely used for simulating thermal radiative transfer and solving the radiation transport equation. During an IMC run a grid network is constructed and particles are sourced into the problem to simulate...

Landman, Jacob Taylor

2013-09-19T23:59:59.000Z

128

An Analysis Tool for Flight Dynamics Monte Carlo Simulations  

E-Print Network [OSTI]

and analysis work to understand vehicle operating limits and identify circumstances that lead to mission failure. A Monte Carlo simulation approach that varies a wide range of physical parameters is typically used to generate thousands of test cases...

Restrepo, Carolina 1982-

2011-05-20T23:59:59.000Z

129

Pressure fluctuations beneath turbulent spots and instability wave packets in a hypersonic boundary layer.  

SciTech Connect (OSTI)

The development of turbulent spots in a hypersonic boundary layer was studied on the nozzle wall of the Boeing/AFOSR Mach-6 Quiet Tunnel. Under quiet flow conditions, the nozzle wall boundary layer remains laminar and grows very thick over the long nozzle length. This allows the development of large turbulent spots that can be readily measured with pressure transducers. Measurements of naturally occurring wave packets and developing turbulent spots were made. The peak frequencies of these natural wave packets were in agreement with second-mode computations. For a controlled study, the breakdown of disturbances created by spark and glow perturbations were studied at similar freestream conditions. The spark perturbations were the most effective at creating large wave packets that broke down into turbulent spots. The flow disturbances created by the controlled perturbations were analyzed to obtain amplitude criteria for nonlinearity and breakdown as well as the convection velocities of the turbulent spots. Disturbances first grew into linear instability waves and then quickly became nonlinear. Throughout the nonlinear growth of the wave packets, large harmonics are visible in the power spectra. As breakdown begins, the peak amplitudes of the instability waves and harmonics decrease into the rising broad-band frequencies. Instability waves are still visible on either side of the growing turbulent spots during this breakdown process.

Beresh, Steven Jay; Casper, Katya M.; Schneider, Steven P. (Purdue University, West Lafayette, IN)

2010-12-01T23:59:59.000Z

130

Monte Carlos of the new generation: status and progress  

SciTech Connect (OSTI)

Standard parton shower monte carlos are designed to give reliable descriptions of low-pT physics. In the very high-energy regime of modern colliders, this is may lead to largely incorrect predictions of the basic reaction processes. This motivated the recent theoretical efforts aimed at improving monte carlos through the inclusion of matrix elements computed beyond the leading order in QCD. I briefly review the progress made, and discuss bottom production at the Tevatron.

Frixione, Stefano [INFN, Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

2005-03-22T23:59:59.000Z

131

Implications of Monte Carlo Statistical Errors in Criticality Safety Assessments  

SciTech Connect (OSTI)

Most criticality safety calculations are performed using Monte Carlo techniques because of Monte Carlo's ability to handle complex three-dimensional geometries. For Monte Carlo calculations, the more histories sampled, the lower the standard deviation of the resulting estimates. The common intuition is, therefore, that the more histories, the better; as a result, analysts tend to run Monte Carlo analyses as long as possible (or at least to a minimum acceptable uncertainty). For Monte Carlo criticality safety analyses, however, the optimization situation is complicated by the fact that procedures usually require that an extra margin of safety be added because of the statistical uncertainty of the Monte Carlo calculations. This additional safety margin affects the impact of the choice of the calculational standard deviation, both on production and on safety. This paper shows that, under the assumptions of normally distributed benchmarking calculational errors and exact compliance with the upper subcritical limit (USL), the standard deviation that optimizes production is zero, but there is a non-zero value of the calculational standard deviation that minimizes the risk of inadvertently labeling a supercritical configuration as subcritical. Furthermore, this value is shown to be a simple function of the typical benchmarking step outcomes--the bias, the standard deviation of the bias, the upper subcritical limit, and the number of standard deviations added to calculated k-effectives before comparison to the USL.

Pevey, Ronald E.

2005-09-15T23:59:59.000Z

133

Use of treatment log files in spot scanning proton therapy as part of patient-specific quality assurance  

SciTech Connect (OSTI)

Purpose: The purpose of this work was to assess the monitor unit (MU) values and position accuracy of spot scanning proton beams as recorded by the daily treatment logs of the treatment control system, and furthermore establish the feasibility of using the delivered spot positions and MU values to calculate and evaluate delivered doses to patients. Methods: To validate the accuracy of the recorded spot positions, the authors generated and executed a test treatment plan containing nine spot positions, to which the authors delivered ten MU each. The spot positions were measured with radiographic films and Matrixx 2D ion-chambers array placed at the isocenter plane and compared for displacements from the planned and recorded positions. Treatment logs for 14 patients were then used to determine the spot MU values and position accuracy of the scanning proton beam delivery system. Univariate analysis was used to detect any systematic error or large variation between patients, treatment dates, proton energies, gantry angles, and planned spot positions. The recorded patient spot positions and MU values were then used to replace the spot positions and MU values in the plan, and the treatment planning system was used to calculate the delivered doses to patients. The results were compared with the treatment plan. Results: Within a treatment session, spot positions were reproducible within {+-}0.2 mm. The spot positions measured by film agreed with the planned positions within {+-}1 mm and with the recorded positions within {+-}0.5 mm. The maximum day-to-day variation for any given spot position was within {+-}1 mm. For all 14 patients, with {approx}1 500 000 spots recorded, the total MU accuracy was within 0.1% of the planned MU values, the mean (x, y) spot displacement from the planned value was (-0.03 mm, -0.01 mm), the maximum (x, y) displacement was (1.68 mm, 2.27 mm), and the (x, y) standard deviation was (0.26 mm, 0.42 mm). The maximum dose difference between calculated dose to the patient based on the plan and recorded data was within 2%. Conclusions: The authors have shown that the treatment log file in a spot scanning proton beam delivery system is precise enough to serve as a quality assurance tool to monitor variation in spot position and MU value, as well as the delivered dose uncertainty from the treatment delivery system. The analysis tool developed here could be useful for assessing spot position uncertainty and thus dose uncertainty for any patient receiving spot scanning proton beam therapy.

Li Heng; Sahoo, Narayan; Poenisch, Falk; Suzuki, Kazumichi; Li Yupeng; Li Xiaoqiang; Zhang Xiaodong; Gillin, Michael T.; Zhu, X. Ronald [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Lee, Andrew K. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

2013-02-15T23:59:59.000Z

134

Magnetic dipole discharges. II. Cathode and anode spot discharges and probe diagnostics  

SciTech Connect (OSTI)

The high current regime of a magnetron-type discharge has been investigated. The discharge uses a permanent magnet as a cold cathode which emits secondary electrons while the chamber wall or a grounded electrode serves as the anode. As the discharge voltage is increased, the magnet develops cathode spots, which are short duration arcs that provide copious electrons to increase the discharge current dramatically. Short (1 ?s), high current (200 A) and high voltage (750 V) discharge pulses are produced in a relaxation instability between the plasma and a charging capacitor. Spots are also observed on a negatively biased plane Langmuir probe. The probe current pulses are as large as those on the magnet, implying that the high discharge current does not depend on the cathode surface area but on the properties of the spots. The fast current pulses produce large inductive voltages, which can reverse the electrical polarity of the magnet and temporarily operate it as an anode. The discharge current may also oscillate at the frequency determined by the charging capacitor and the discharge circuit inductance. Each half cycle of high-current current pulses exhibits a fast (?10 ns) current rise when a spot is formed. It induces high frequency (10–100 MHz) transients and ringing oscillations in probes and current circuits. Most probes behave like unmatched antennas for the electromagnetic pulses of spot discharges. Examples are shown to distinguish the source of oscillations and some rf characteristics of Langmuir probes.

Stenzel, R. L.; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States); Ionita, C.; Schrittwieser, R. [Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck (Austria)] [Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck (Austria)

2013-08-15T23:59:59.000Z

135

The Observer March 2003 page 3 CSU Fresno 16" SCT at f/38 & Jupiter's Great Red Spot  

E-Print Network [OSTI]

The Observer March 2003 page 3 CSU Fresno 16" SCT at f/38 & Jupiter's Great Red Spot By Greg Morgan in March that the Great Red Spot will be making a central meridian crossing along with the shadow of one in the region of the Great Red Spot. Similarly, on Tuesday evening April 1st , from 10:24 PM to 1:48 AM PDT, Io

Ringwald, Frederick A.

136

A Multivariate Time Series Method for Monte Carlo Reactor Analysis  

SciTech Connect (OSTI)

A robust multivariate time series method has been established for the Monte Carlo calculation of neutron multiplication problems. The method is termed Coarse Mesh Projection Method (CMPM) and can be implemented using the coarse statistical bins for acquisition of nuclear fission source data. A novel aspect of CMPM is the combination of the general technical principle of projection pursuit in the signal processing discipline and the neutron multiplication eigenvalue problem in the nuclear engineering discipline. CMPM enables reactor physicists to accurately evaluate major eigenvalue separations of nuclear reactors with continuous energy Monte Carlo calculation. CMPM was incorporated in the MCNP Monte Carlo particle transport code of Los Alamos National Laboratory. The great advantage of CMPM over the traditional Fission Matrix method is demonstrated for the three space-dimensional modeling of the initial core of a pressurized water reactor.

Taro Ueki

2008-08-14T23:59:59.000Z

137

Quantum Monte Carlo Calculations of Light Nuclei Using Chiral Potentials  

E-Print Network [OSTI]

We present the first Green's function Monte Carlo calculations of light nuclei with nuclear interactions derived from chiral effective field theory up to next-to-next-to-leading order. Up to this order, the interactions can be constructed in a local form and are therefore amenable to quantum Monte Carlo calculations. We demonstrate a systematic improvement with each order for the binding energies of $A=3$ and $A=4$ systems. We also carry out the first few-body tests to study perturbative expansions of chiral potentials at different orders, finding that higher-order corrections are more perturbative for softer interactions. Our results confirm the necessity of a three-body force for correct reproduction of experimental binding energies and radii, and pave the way for studying few- and many-nucleon systems using quantum Monte Carlo methods with chiral interactions.

J. E. Lynn; J. Carlson; E. Epelbaum; S. Gandolfi; A. Gezerlis; A. Schwenk

2014-11-09T23:59:59.000Z

138

Real-time spot size camera for pulsed high-energy radiographic machines  

SciTech Connect (OSTI)

The focal spot size of an x-ray source is a critical parameter which degrades resolution in a flash radiograph. For best results, a small round focal spot is required. Therefore, a fast and accurate measurement of the spot size is highly desirable to facilitate machine tuning. This paper describes two systems developed for Los Alamos National Laboratory`s Pulsed High-Energy Radiographic Machine Emitting X-rays (PHERMEX) facility. The first uses a CCD camera combined with high-brightness floors, while the second utilizes phosphor storage screens. Other techniques typically record only the line spread function on radiographic film, while systems in this paper measure the more general two-dimensional point-spread function and associated modulation transfer function in real time for shot-to-shot comparison.

Watson, S.A.

1993-06-01T23:59:59.000Z

139

Real-time spot size camera for pulsed high-energy radiographic machines  

SciTech Connect (OSTI)

The focal spot size of an x-ray source is a critical parameter which degrades resolution in a flash radiograph. For best results, a small round focal spot is required. Therefore, a fast and accurate measurement of the spot size is highly desirable to facilitate machine tuning. This paper describes two systems developed for Los Alamos National Laboratory's Pulsed High-Energy Radiographic Machine Emitting X-rays (PHERMEX) facility. The first uses a CCD camera combined with high-brightness floors, while the second utilizes phosphor storage screens. Other techniques typically record only the line spread function on radiographic film, while systems in this paper measure the more general two-dimensional point-spread function and associated modulation transfer function in real time for shot-to-shot comparison.

Watson, S.A.

1993-01-01T23:59:59.000Z

140

Fast neutron fluxes in pressure vessels using Monte Carlo methods  

SciTech Connect (OSTI)

The objective of this project is to determine the feasibility of calculating the fast neutron flux in the pressure vessel of a pressurized water reactor by Monte Carlo methods. Neutron reactions reduce the ductility of the steel and thus limit the useful life of this important reactor component. This work was performed for Virginia Power (VEPCO). VIM is a continuous-energy Monte Carlo code which provides a versatile geometrical capability and a neutron physics data base closely representing the EDNF/B-IV data from which it was derived.

Edlund, M.C.; Thomas, J.R.

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Control of Black Spot of Roses with Sulphur-Copper Dust.  

E-Print Network [OSTI]

TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, Director College Station, Texas BULLETIN NO. 648 APRIL, 1944 CONTROL OF BLACK SPOT OF ROSES WITH SULPHUR-COPPER DUST E. W. LYLE Division of Plant Pathology and Physiology l ,i- ' 7, r... ......................................................................................................... - . CONTROLOFBLACKSPOTOFROSES WITH SULPHUR-COPPER DUST' E. W. Lyle,' Plant Pathologist Black spot is a fungous disease of the rose plant that attacks ' leaves during rainy, humid weather (5). It is caused by the fung Diplocarpon rosae. As the name of the disease implies...

Lyle, E. W. (Eldon W.)

1944-01-01T23:59:59.000Z

142

Selection Criteria Based on Monte Carlo Simulation and Cross Validation  

E-Print Network [OSTI]

Shang Bowling Green State University, USA Abstract In the mixed modeling framework, Monte Carlo State University, Bowling Green, OH 43403. #12;1 Introduction The Akaike (1973, 1974) information-mail: jshang@bgnet.bgsu.edu. Department of Mathematics and Statistics, 450 Math Science Building, Bowling Green

Shang, Junfeng

143

Difficulties in vector-parallel processing of Monte Carlo codes  

SciTech Connect (OSTI)

Experiences with vectorization of production-level Monte Carlo codes such as KENO-IV, MCNP, VIM, and MORSE have shown that it is difficult to attain high speedup ratios on vector processors because of indirect addressing, nests of conditional branches, short vector length, cache misses, and operations for realization of robustness and generality. A previous work has already shown that the first, second, and third difficulties can be resolved by using special computer hardware for vector processing of Monte Carlo codes. Here, the fourth and fifth difficulties are discussed in detail using the results for a vectorized version of the MORSE code. As for the fourth difficulty, it is shown that the cache miss-hit ratio affects execution times of the vectorized Monte Carlo codes and the ratio strongly depends on the number of the particles simultaneously tracked. As for the fifth difficulty, it is shown that remarkable speedup ratios are obtained by removing operations that are not essential to the specific problem being solved. These experiences have shown that if a production-level Monte Carlo code system had a capability to selectively construct source coding that complements the input data, then the resulting code could achieve much higher performance.

Higuchi, Kenji; Asai, Kiyoshi [Japan Atomic Energy Research Inst., Tokyo (Japan). Center for Promotion of Computational Science and Engineering; Hasegawa, Yukihiro [Research Organization for Information Science and Technology, Tokai, Ibaraki (Japan)

1997-09-01T23:59:59.000Z

144

Quantum Monte Carlo calculations of symmetric nuclear matter  

E-Print Network [OSTI]

We present an accurate numerical study of the equation of state of nuclear matter based on realistic nucleon--nucleon interactions by means of Auxiliary Field Diffusion Monte Carlo (AFDMC) calculations. The AFDMC method samples the spin and isospin degrees of freedom allowing for quantum simulations of large nucleonic systems and can provide quantitative understanding of problems in nuclear structure and astrophysics.

Stefano Gandolfi; Francesco Pederiva; Stefano Fantoni; Kevin E. Schmidt

2007-04-13T23:59:59.000Z

145

Evolutionary Monte Carlo for protein folding simulations Faming Lianga)  

E-Print Network [OSTI]

Evolutionary Monte Carlo for protein folding simulations Faming Lianga) Department of Statistics to simulations of protein folding on simple lattice models, and to finding the ground state of a protein. In all structures in protein folding. The numerical results show that it is drastically superior to other methods

Liang, Faming

146

ENVIRONMENTAL MODELING: 1 APPLICATIONS: MONTE CARLO SENSITIVITY SIMULATIONS  

E-Print Network [OSTI]

SIMULATIONS TO THE PROBLEM OF AIR POLLUTION TRANSPORT 3 1.1 The Danish Eulerian Model #12;Chapter 1 APPLICATIONS: MONTE CARLO SENSITIVITY SIMULATIONS TO THE PROBLEM OF AIR POLLUTION of pollutants in a real-live scenario of air-pollution transport over Europe. First, the developed technique

Dimov, Ivan

147

Monte Carlo Simulations of Thermal Conductivity in Nanoporous Si Membranes  

E-Print Network [OSTI]

candidates for thermoelectric materials as they can provide extremely low thermal conductivity , relatively of boundary scattering on the thermal conductivity. We show that the material porosity strongly affects1 Monte Carlo Simulations of Thermal Conductivity in Nanoporous Si Membranes Stefanie Wolf1

148

The Rhenish stoneware from the Monte Cristi shipwreck, Dominican Republic  

E-Print Network [OSTI]

Discovered in 1966 off the north coast of the Dominican Republic, the Monte Cristi shipwreck represents the remains of an English-built ship carrying a Dutch cargo that sank in Spanish waters during the mid-17th century. Despite heavy salvage...

Lessmann, Anne Wood

1997-01-01T23:59:59.000Z

149

Multiple Overlapping Tiles for Contextual Monte Carlo Tree Search  

E-Print Network [OSTI]

generation of libraries for linear transforms [4] or active learning [8]. The use of Monte Carlo simulations is to group simulations where two particular actions have been selected by the same player. Then, we learn simulations in the MCTS algorithm has been proposed. We first present reinforcement learning, the principle

Paris-Sud XI, Université de

150

A MONTE CARLO SIMULATION OF WATER FLOW IN VARIABLY ...  

E-Print Network [OSTI]

A Monte Carlo simulation method is employed to study groundwater flow in variably saturated fractal porous ... Richards' equation which is solved using a hybridized mixed finite element procedure. ... INTRODUCTION ... This conclusion has led to the development of stochastic models for the basic un- ... different soils.

1910-10-30T23:59:59.000Z

151

Parallel algorithms for Monte Carlo particle transport simulation on exascale computing architectures  

E-Print Network [OSTI]

Monte Carlo particle transport methods are being considered as a viable option for high-fidelity simulation of nuclear reactors. While Monte Carlo methods offer several potential advantages over deterministic methods, there ...

Romano, Paul K. (Paul Kollath)

2013-01-01T23:59:59.000Z

152

Monte Carlo Filtering on Lie Groups Alessandro Chiuso 1 and Stefano Soatto 2  

E-Print Network [OSTI]

Monte Carlo Filtering on Lie Groups Alessandro Chiuso 1 and Stefano Soatto 2 Abstract We propose to be consistent with the updated conditional distribution. The algorithm proposed, like other Monte Carlo methods

Soatto, Stefano

153

Application of Dynamic Monte Carlo Technique in Proton Beam Radiotherapy using Geant4 Simulation Toolkit  

E-Print Network [OSTI]

Monte Carlo method has been successfully applied in simulating the particles transport problems. Most of the Monte Carlo simulation tools are static and they can only be used to perform the static simulations for the problems with fixed physics...

Guan, Fada 1982-

2012-04-27T23:59:59.000Z

154

The theoretical development of a new high speed solution for Monte Carlo radiation transport computations  

E-Print Network [OSTI]

Advancements in parallel and cluster computing have made many complex Monte Carlo simulations possible in the past several years. Unfortunately, cluster computers are large, expensive, and still not fast enough to make the Monte Carlo technique...

Pasciak, Alexander Samuel

2007-04-25T23:59:59.000Z

155

Experimental results obtained during fatigue testing of a spot-welded lap-shear structural-joint specimen are  

E-Print Network [OSTI]

in a number of industries. Spot welding is the traditional method of assembly for steel-based automotive and construction of vehicular structures indicate a strong diversification of material usage, with aluminum and polymeric composites projected to play a major role. While aluminum is amenable to both spot welding

Giurgiutiu, Victor

156

Price-based Congestion-Control in Wi-Fi Hot Spots Roberto Battiti(*), Marco Conti(**), Enrico Gregori(**), Mikalai Sabel(*)  

E-Print Network [OSTI]

if they are in the transmission range of an access point. A new business model, named Wi-Fi Hot Spots, is now emerging to exploit offer with Wi-Fi. To reach an efficient use of the scarce bandwidth resources, market mechanisms the potentialities of this technology. A hot spot is a "critical" business area, e.g., airports, stations, hotels

Paris-Sud XI, Université de

157

Forecasting the conditional volatility of oil spot and futures prices with structural breaks and long memory models  

E-Print Network [OSTI]

Forecasting the conditional volatility of oil spot and futures prices with structural breaks of oil spot and futures prices using three GARCH-type models, i.e., linear GARCH, GARCH with structural that oil price fluctuations influence economic activity and financial sector (e.g., Jones and Kaul, 1996

Paris-Sud XI, Université de

158

A Scalable Soft Spot Analysis Methodology for Compound Noise Effects in Nano-meter Circuits  

E-Print Network [OSTI]

A Scalable Soft Spot Analysis Methodology for Compound Noise Effects in Nano-meter Circuits Chong@ece.ucsd.edu ABSTRACT Circuits using nano-meter technologies are becoming increasingly vulnerable to signal interference methodology to study the vulnerability of digital ICs exposed to nano-meter noise and transient soft errors

California at San Diego, University of

159

Energy Spot Price Models and Spread Options Pricing Samuel Hikspoors and Sebastian Jaimungal a  

E-Print Network [OSTI]

Energy Spot Price Models and Spread Options Pricing Samuel Hikspoors and Sebastian Jaimungal In this article, we construct forward price curves and value a class of two asset exchange options for energy the implied market prices of risk for this commodity. 1. Introduction The energy commodity markets

Jaimungal, Sebastian

160

ESTIMATING THE VOLATILITY OF SPOT PRICES IN RESTRUCTURED ELECTRICITY MARKETS AND THE IMPLICATIONS FOR OPTION VALUES  

E-Print Network [OSTI]

Draft 1e ESTIMATING THE VOLATILITY OF SPOT PRICES IN RESTRUCTURED ELECTRICITY MARKETS path. Accurate valuation of claims based on competitive electricity prices has proved problematic, as electricity price data are not well represented by traditional commodity price models of Brownian motion

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Forecasting electricity spot market prices with a k-factor GIGARCH process.  

E-Print Network [OSTI]

Forecasting electricity spot market prices with a k-factor GIGARCH process. Abdou Kâ Diongue this method to the German electricity price market for the period August 15, 2000 - De- cember 31, 2002 and we; Electricity prices; Forecast; GIGARCH process. Corresponding author: Universite Gaston Berger de Saint

Paris-Sud XI, Université de

162

Joint Modelling of Gas and Electricity spot prices N. Frikha1 , V. Lemaire2  

E-Print Network [OSTI]

Joint Modelling of Gas and Electricity spot prices N. Frikha1 , V. Lemaire2 October 9, 2009 for developing a risk management framework as well as pricing of options. Many derivatives on both electricity and electricity prices is a relevant issue. Numerous diffusion-type and econometric models have been proposed

163

Fracture toughness of the molten zone of resistance spot welds Florent Krajcarz1,2*  

E-Print Network [OSTI]

). In these tests, the load vs. load line displacement curve is recorded to derive the weld strength (i.e. maximal of the base metal still significantly influences the load vs. displacement curve, yet to a lesser extent than and the crack extension resistance of the molten zone of resistance spot welds under Mode I loading has been

Paris-Sud XI, Université de

164

On the mechanism of operation of a cathode spot cell in a vacuum arc  

SciTech Connect (OSTI)

The erosive structures formed on a tungsten cathode as a result of the motion of the cathode spot of a vacuum arc over the cathode surface have been examined. It has been found that the average mass of a cathode microprotrusion having the shape of a solidified jet is approximately equal to the mass of ions removed from the cathode within the lifetime of a cathode spot cell carrying a current of several amperes. The time of formation of a new liquid-metal jet under the action of the reactive force of the plasma ejected by the cathode spot is about 10?ns, which is comparable to the lifetime of a cell. The growth rate of a liquid-metal jet is ?10{sup 4}?cm/s. The geometric shape and size of a solidified jet are such that a new explosive emission center (spot cell) can be initiated within several nanoseconds during the interaction of the jet with the dense cathode plasma. This is the underlying mechanism of the self-sustained operation of a vacuum arc.

Mesyats, G. A.; Petrov, A. A. [P. N. Lebedev Physical Institute, RAS, 53 Leninsky Ave., Moscow 119991 (Russian Federation); Bochkarev, M. B. [Institute of Electrophysics, UB, RAS, 106 Amundsen St., Ekaterinburg 620016 (Russian Federation); Barengolts, S. A., E-mail: sb@nsc.gpi.ru [A. M. Prokhorov General Physics Institute, RAS, 38 Vavilov St., Moscow 119991 (Russian Federation)

2014-05-05T23:59:59.000Z

165

THE FROBENIUS INTEGRABILITY THEOREM AND THE BLIND-SPOT PROBLEM FOR MOTOR VEHICLES  

E-Print Network [OSTI]

-side automotive mirror that has no blind-spot or distortion. While reasonably good solutions have been found driver-side mirror compared with a aluminum prototype designed using the method described in [7, the issue of the driver's field of view is a crucial one for automotive safety. According to a U

Moskow, Shari

166

SPIRIT-IPY: List of Publications SPOT 5 stereoscopic survey of Polar Ice: Reference Images &  

E-Print Network [OSTI]

, A. and Gallee, H.: Modeling the mass and surface heat budgets in a coastal blue ice area of AdelieSPIRIT-IPY: List of Publications SPOT 5 stereoscopic survey of Polar Ice: Reference Images stereoscopic survey of Polar Ice: Reference Images and Topographies during the fourth International Polar Year

Berthier, Etienne

167

Essays on price dynamics, discovery, and dynamic threshold effects among energy spot markets in North America  

E-Print Network [OSTI]

Pool (SPP), Entergy (ENT), and Electric Reliability Council of Texas (ERCOT). Approximate locations of the spot markets are shown in Figure 2.1. Plots of the price series for each market are provided in Figure 2.2. One day lagged U.S. aggregate...

Park, Haesun

2005-11-01T23:59:59.000Z

168

Integrated thermal-microstructure model to predict the property gradients in resistance spot steel welds  

SciTech Connect (OSTI)

An integrated model approach was proposed for relating resistance welding parameters to weldment properties. An existing microstructure model was used to determine the microstructural and property gradients in resistance spot welds of plain carbon steel. The effect of these gradients on the weld integrity was evaluated with finite element analysis. Further modifications to this integrated thermal-microstructure model are discussed.

Babu, S.S.; Riemer, B.W.; Santella, M.L. [Oak Ridge National Lab., TN (United States); Feng, Z. [Edison Welding Inst., Columbus, OH (United States)

1998-11-01T23:59:59.000Z

169

Detection, tracking and analysis of turbulent spots and other coherent structures  

E-Print Network [OSTI]

transition. 1 Jacques Lewalle2 and David E. Ashpis3 Abstract Transition on turbine blades is an important of this preliminary study was to evaluate which spot properties can be quanti ed based on hot lm data, and which seem station, which provides smooth data to measure the phase relative to the rst stage blade passing

Lewalle, Jacques

170

Reduced form electricity spot price modeling with a view towards spike risk  

E-Print Network [OSTI]

Reduced form electricity spot price modeling with a view towards spike risk Prof. Dr. Meyer. Februar 2010, 16:15 Uhr Seminarraum, LudwigstraĂ?e 33 I The recent deregulation of electricity markets has led to the creation of energy exchanges, where the electricity is freely traded. We study the most

Gerkmann, Ralf

171

Futures pricing in electricity markets based on stable CARMA spot models  

E-Print Network [OSTI]

Futures pricing in electricity markets based on stable CARMA spot models Gernot M¨uller Vortrag im years, electricity markets throughout the world have undergone massive changes due to deregulations risk but also against price movements. Consequently, statistical modeling and estimation of electricity

Gerkmann, Ralf

172

DROPLET-BASED HOT SPOT COOLING USING TOPLESS DIGITAL MICROFLUIDICS ON A PRINTED CIRCUIT BOARD  

E-Print Network [OSTI]

DROPLET-BASED HOT SPOT COOLING USING TOPLESS DIGITAL MICROFLUIDICS ON A PRINTED CIRCUIT BOARD Phil demonstrated a cooling method on a "digital microfluidics" platform whereby discrete droplets are manipulated and the effective flow rate of the droplets. The results presented here suggest that digital microfluidics

Paris-Sud XI, Université de

173

Mapping the Energy Distribution of SERRS Hot Spots from Anti-Stokes to Stokes Intensity Ratios  

E-Print Network [OSTI]

Mapping the Energy Distribution of SERRS Hot Spots from Anti- Stokes to Stokes Intensity Ratios in the anti-Stokes to Stokes intensity ratios in single-molecule surface-enhanced resonance Raman scattering-enhanced Raman scattering. Moreover, a methodology to estimate the distribution of resonance energies

Brolo, Alexandre G.

174

21 Apr 2006 IPSN / SPOTS `06 Trio: Enabling Sustainable and Scalable  

E-Print Network [OSTI]

management. Use energy harvesting. Improve energy mgmt. Reduce power draw. #12;21 Apr 2006 IPSN / SPOTS `06 harvesting · Improve energy "transfer" ­ Lower operating voltage ­ Adapt load (e.g. MPP) · Decrease power ­ Increasing Lifetime through Solar Energy Solar Cell Short Circuit Current Richmond Field Station, August 24

California at Berkeley, University of

175

Resistance of Kentucky Bluegrass Cultivars to Necrotic Ring Spot by Tom Hsiang and Gary A Chastagner  

E-Print Network [OSTI]

Resistance of Kentucky Bluegrass Cultivars to Necrotic Ring Spot by Tom Hsiang and Gary, but is especially destructive on Kentucky bluegrass (Poa pratensis L.) (Smiley et al., 1992; Worf et al., 1986 stands of Kentucky bluegrass. Symptoms are small, pale, straw-coloured patches of turf a few cm

Hsiang, Tom

176

SciTech Connect: Fast Monte Carlo for radiation therapy: the...  

Office of Scientific and Technical Information (OSTI)

MEDICINE, BASIC STUDIES; RADIOTHERAPY; PLANNING; COMPUTER CALCULATIONS; RADIATION DOSE DISTRIBUTIONS; MONTE CARLO METHOD; THREE-DIMENSIONAL CALCULATIONS; COMPUTERIZED TOMOGRAPHY...

177

Hot-spot mix in ignition-scale implosions on the NIF  

SciTech Connect (OSTI)

Ignition of an inertial confinement fusion (ICF) target depends on the formation of a central hot spot with sufficient temperature and areal density. Radiative and conductive losses from the hot spot can be enhanced by hydrodynamic instabilities. The concentric spherical layers of current National Ignition Facility (NIF) ignition targets consist of a plastic ablator surrounding a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. The Rev. 5 ablator is doped with Ge to minimize preheat of the ablator closest to the DT ice caused by Au M-band emission from the hohlraum x-ray drive [D. S. Clark et al., Phys. Plasmas 17, 052703 (2010)]. Richtmyer-Meshkov and Rayleigh-Taylor hydrodynamic instabilities seeded by high-mode () ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase [B. A. Hammel et al., Phys. Plasmas 18, 056310 (2011)]. As the shell decelerates, it compresses the fuel vapor, forming a hot spot. K-shell line emission from the ionized Ge that has penetrated into the hot spot provides an experimental signature of hot-spot mix. The Ge emission from tritium-hydrogen-deuterium (THD) and deuterium-tritium (DT) cryogenic targets and gas-filled plastic-shell capsules, which replace the THD layer with a mass-equivalent CH layer, was examined. The inferred amount of hot-spot-mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code [J. J. MacFarlane et al., High Energy Density Phys. 3, 181 (2006)], is typically below the 75-ng allowance for hot-spot mix [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. Predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.

Regan, S. P.; Epstein, R.; McCrory, R. L.; Meyerhofer, D. D.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States); Hammel, B. A.; Suter, L. J.; Ralph, J.; Scott, H.; Barrios, M. A.; Bradley, D. K.; Callahan, D. A.; Cerjan, C.; Collins, G. W.; Dixit, S. N.; Doeppner, T.; Edwards, M. J.; Farley, D. R.; Glenn, S.; Glenzer, S. H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

2012-05-15T23:59:59.000Z

178

Role of hydrodynamic instability growth in hot-spot mass gain and fusion performance of inertial confinement fusion implosions  

SciTech Connect (OSTI)

In an inertial confinement fusion target, energy loss due to thermal conduction from the hot-spot will inevitably ablate fuel ice into the hot-spot, resulting in a more massive but cooler hot-spot, which negatively impacts fusion yield. Hydrodynamic mix due to Rayleigh-Taylor instability at the gas-ice interface can aggravate the problem via an increased gas-ice interfacial area across which energy transfer from the hot-spot and ice can be enhanced. Here, this mix-enhanced transport effect on hot-spot fusion-performance degradation is quantified using contrasting 1D and 2D hydrodynamic simulations, and its dependence on effective acceleration, Atwood number, and ablation speed is identified.

Srinivasan, Bhuvana, E-mail: srinbhu@vt.edu [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Aerospace and Ocean Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Tang, Xian-Zhu, E-mail: xtang@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2014-10-15T23:59:59.000Z

179

Experimental investigation of bright spots in broadband, gated x-ray images of ignition-scale implosions on the National Ignition Facility  

SciTech Connect (OSTI)

Bright spots in the hot spot intensity profile of gated x-ray images of ignition-scale implosions at the National Ignition Facility [G. H. Miller et al., Opt. Eng. 443, (2004)] are observed. X-ray images of cryogenically layered deuterium-tritium (DT) and tritium-hydrogen-deuterium (THD) ice capsules, and gas filled plastic shell capsules (Symcap) were recorded along the hohlraum symmetry axis. Heterogeneous mixing of ablator material and fuel into the hot spot (i.e., hot-spot mix) by hydrodynamic instabilities causes the bright spots. Hot-spot mix increases the radiative cooling of the hot spot. Fourier analysis of the x-ray images is used to quantify the evolution of bright spots in both x- and k-space. Bright spot images were azimuthally binned to characterize bright spot location relative to known isolated defects on the capsule surface. A strong correlation is observed between bright spot location and the fill tube for both Symcap and cryogenically layered DT and THD ice targets, indicating the fill tube is a significant seed for the ablation front instability causing hot-spot mix. The fill tube is the predominant seed for Symcaps, while other capsule non-uniformities are dominant seeds for the cryogenically layered DT and THD ice targets. A comparison of the bright spot power observed for Si- and Ge-doped ablator targets shows heterogeneous mix in Symcap targets is mostly material from the doped ablator layer.

Barrios, M. A.; Suter, L. J.; Glenn, S.; Benedetti, L. R.; Bradley, D. K.; Collins, G. W.; Hammel, B. A.; Izumi, N.; Ma, T.; Scott, H.; Smalyuk, V. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Regan, S. P.; Epstein, R. [Laboratory for Laser Energetics, University of Rochester 250 East River Road, Rochester, New York 14623-199 (United States)] [Laboratory for Laser Energetics, University of Rochester 250 East River Road, Rochester, New York 14623-199 (United States); Kyrala, G. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2013-07-15T23:59:59.000Z

180

Monte Carlo Methods for Uncertainty Quantification Mathematical Institute, University of Oxford  

E-Print Network [OSTI]

Lecture 1: Introduction and Monte Carlo basics some model applications random number generation Monte force being outside some specified range Note: if we turn this into a full finite element analysis on the boundary. Mike Giles (Oxford) Monte Carlo methods October 25, 2013 7 / 28 #12;Application 3 In modelling

Giles, Mike

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Finite element simulation of laser spot welding A. De, S. K. Maiti, C. A. Walsh and H. K. D. H. Bhadeshia  

E-Print Network [OSTI]

Finite element simulation of laser spot welding A. De, S. K. Maiti, C. A. Walsh and H. K. D. H laser spot welding, taking into account the temperature dependence of the physical properties and latent formation during laser spot welding, although the `double ellipsoidal' representation requires an a priori

Cambridge, University of

182

Operating conditions for the generation of stable anode spot plasma in front of a positively biased electrode  

SciTech Connect (OSTI)

Stability of an anode spot plasma, which is an additional high density plasma generated in front of a positively biased electrode immersed in ambient plasma, is a critical issue for its utilization to various types of ion sources. In this study, operating conditions for the generation of stable anode spot plasmas are experimentally investigated. Diagnostics of the bias current flowing into the positively biased electrode and the properties of ambient plasma reveal that unstable nature of the anode spot is deeply associated with the reduction of double layer potential between the anode spot plasma and the ambient plasma. It is found that stability of the anode spot plasma can be improved with increasing the ionization rate in ambient plasma so as to compensate the loss of electrons across the double layer or with enlarging the area of the biased electrode to prevent electron accumulation inside the anode spot. The results obtained from the present study give the guideline for operating conditions of anode spot plasmas as an ion source with high brightness.

Park, Yeong-Shin; Lee, Yuna; Dang, Jeong-Jeung [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of) [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2014-02-15T23:59:59.000Z

183

Beyond the Born-Oppenheimer approximation with quantum Monte Carlo  

E-Print Network [OSTI]

In this work we develop tools that enable the study of non-adiabatic effects with variational and diffusion Monte Carlo methods. We introduce a highly accurate wave function ansatz for electron-ion systems that can involve a combination of both fixed and quantum ions. We explicitly calculate the ground state energies of H$_{2}$, LiH, H$_{2}$O and FHF$^{-}$ using fixed-node quantum Monte Carlo with wave function nodes that explicitly depend on the ion positions. The obtained energies implicitly include the effects arising from quantum nuclei and electron-nucleus coupling. We compare our results to the best theoretical and experimental results available and find excellent agreement.

Tubman, Norm M; Hammes-Schiffer, Sharon; Ceperley, David M

2014-01-01T23:59:59.000Z

184

Fixed-Node Diffusion Monte Carlo of Lithium Systems  

E-Print Network [OSTI]

We study lithium systems over a range of number of atoms, e.g., atomic anion, dimer, metallic cluster, and body-centered cubic crystal by the diffusion Monte Carlo method. The calculations include both core and valence electrons in order to avoid any possible impact by pseudo potentials. The focus of the study is the fixed-node errors, and for that purpose we test several orbital sets in order to provide the most accurate nodal hyper surfaces. We compare our results to other high accuracy calculations wherever available and to experimental results so as to quantify the the fixed-node errors. The results for these Li systems show that fixed-node quantum Monte Carlo achieves remarkably high accuracy total energies and recovers 97-99 % of the correlation energy.

Rasch, Kevin

2015-01-01T23:59:59.000Z

185

Efficient, automated Monte Carlo methods for radiation transport  

SciTech Connect (OSTI)

Monte Carlo simulations provide an indispensible model for solving radiative transport problems, but their slow convergence inhibits their use as an everyday computational tool. In this paper, we present two new ideas for accelerating the convergence of Monte Carlo algorithms based upon an efficient algorithm that couples simulations of forward and adjoint transport equations. Forward random walks are first processed in stages, each using a fixed sample size, and information from stage k is used to alter the sampling and weighting procedure in stage k+1. This produces rapid geometric convergence and accounts for dramatic gains in the efficiency of the forward computation. In case still greater accuracy is required in the forward solution, information from an adjoint simulation can be added to extend the geometric learning of the forward solution. The resulting new approach should find widespread use when fast, accurate simulations of the transport equation are needed.

Kong Rong; Ambrose, Martin [Claremont Graduate University, 150 E. 10th Street, Claremont, CA 91711 (United States); Spanier, Jerome [Claremont Graduate University, 150 E. 10th Street, Claremont, CA 91711 (United States); Beckman Laser Institute and Medical Clinic, University of California, 1002 Health Science Road E., Irvine, CA 92612 (United States)], E-mail: jspanier@uci.edu

2008-11-20T23:59:59.000Z

186

The hybrid Monte Carlo Algorithm and the chiral transition  

SciTech Connect (OSTI)

In this talk the author describes tests of the Hybrid Monte Carlo Algorithm for QCD done in collaboration with Greg Kilcup and Stephen Sharpe. We find that the acceptance in the glubal Metropolis step for Staggered fermions can be tuned and kept large without having to make the step-size prohibitively small. We present results for the finite temperature transition on 4/sup 4/ and 4 x 6/sup 3/ lattices using this algorithm.

Gupta, R.

1987-01-01T23:59:59.000Z

187

Regional Monte Carlo solution of elliptic partial differential equations  

SciTech Connect (OSTI)

A continuous random walk procedure for solving some elliptic partial differential equations at a single point is generalized to estimate the solution everywhere. The Monte Carlo method described here is exact (except at the boundary) in the sense that the only error is the statistical sampling error that tends to zero as the sample size increases. A method to estimate the error introduced at the boundary is provided so that the boundary error can always be made less than the statistical error.

Booth, T.E.

1981-01-01T23:59:59.000Z

188

Monte Carlo approach to nuclei and nuclear matter  

SciTech Connect (OSTI)

We report on the most recent applications of the Auxiliary Field Diffusion Monte Carlo (AFDMC) method. The equation of state (EOS) for pure neutron matter in both normal and BCS phase and the superfluid gap in the low-density regime are computed, using a realistic Hamiltonian containing the Argonne AV8' plus Urbana IX three-nucleon interaction. Preliminary results for the EOS of isospin-asymmetric nuclear matter are also presented.

Fantoni, Stefano [S.I.S.S.A., International School of Advanced Studies, INFN, Sezione di Trieste and INFM, CNR-DEMOCRITOS National Supercomputing Center (Italy); Gandolfi, Stefano; Illarionov, Alexey Yu. [S.I.S.S.A., International School of Advanced Studies, INFN, Sezione di Trieste (Italy); Schmidt, Kevin E. [Department of Physics, Arizona State University (United States); Pederiva, Francesco [Dipartimento di Fisica, University of Trento (Italy); INFM, CNR-DEMOCRITOS National Supercomputing Center (Greece)

2008-10-13T23:59:59.000Z

189

Monte Carlo approach to nuclei and nuclear matter  

E-Print Network [OSTI]

We report on the most recent applications of the Auxiliary Field Diffusion Monte Carlo (AFDMC) method. The equation of state (EOS) for pure neutron matter in both normal and BCS phase and the superfluid gap in the low--density regime are computed, using a realistic Hamiltonian containing the Argonne AV8' plus Urbana IX three--nucleon interaction. Preliminary results for the EOS of isospin--asymmetric nuclear matter are also presented.

Stefano Fantoni; Stefano Gandolfi; Alexey Yu. Illarionov; Kevin E. Schmidt; Francesco Pederiva

2008-07-31T23:59:59.000Z

190

Quantum Monte Carlo Calculations of Symmetric Nuclear Matter  

SciTech Connect (OSTI)

We present an accurate numerical study of the equation of state of nuclear matter based on realistic nucleon-nucleon interactions by means of auxiliary field diffusion Monte Carlo (AFDMC) calculations. The AFDMC method samples the spin and isospin degrees of freedom allowing for quantum simulations of large nucleonic systems and represents an important step forward towards a quantitative understanding of problems in nuclear structure and astrophysics.

Gandolfi, Stefano [Dipartimento di Fisica and INFN, University of Trento, via Sommarive 14, I-38050 Povo, Trento (Italy); Pederiva, Francesco [Dipartimento di Fisica and INFN, University of Trento, via Sommarive 14, I-38050 Povo, Trento (Italy); CNR-DEMOCRITOS National Supercomputing Center, Trieste (Italy); Fantoni, Stefano [Scuola Internazionale Superiore di Studi Avanzati and INFN via Beirut 2/4, 34014 Trieste (Italy); CNR-DEMOCRITOS National Supercomputing Center, Trieste (Italy); Schmidt, Kevin E. [Department of Physics, Arizona State University, Tempe, Arizona (United States)

2007-03-09T23:59:59.000Z

191

Monte-Carlo Simulation for an Aerogel Cherenkov Counter  

E-Print Network [OSTI]

We have developed a Monte-Carlo simulation code for an aerogel \\v Cerenkov Counter which is operated under a strong magnetic field such as 1.5T. This code consists of two parts: photon transportation inside aerogel tiles, and one-dimensional amplification in a fine-mesh photomultiplier tube. It simulates the output photoelectron yields as accurately as 5% with only a single free parameter. This code is applied to simulations for a B-Factory particle-identification system.

Ryuji Suda et al

1997-07-31T23:59:59.000Z

192

MC++: Parallel, portable, Monte Carlo neutron transport in C++  

SciTech Connect (OSTI)

We have developed an implicit Monte Carlo neutron transport code in C++ using the Parallel Object-Oriented Methods and Applications (POOMA) class library. MC++ runs in parallel on and is portable to a wide variety of platforms, including MPPs, clustered SMPs, and individual workstations. It contains appropriate classes and abstractions for particle transport and parallelism. Current capabilities of MC++ are discussed, along with future plans and physics and performance results on many different platforms.

Lee, S.R.; Cummings, J.C. [Los Alamos National Lab., NM (United States); Nolen, S.D. [Texas A& M Univ., College Station, TX (United States). Dept. of Nuclear Engineering

1997-02-01T23:59:59.000Z

193

OBJECT KINETIC MONTE CARLO SIMULATIONS OF MICROSTRUCTURE EVOLUTION  

SciTech Connect (OSTI)

The objective is to report the development of the flexible object kinetic Monte Carlo (OKMC) simulation code KSOME (kinetic simulation of microstructure evolution) which can be used to simulate microstructure evolution of complex systems under irradiation. In this report we briefly describe the capabilities of KSOME and present preliminary results for short term annealing of single cascades in tungsten at various primary-knock-on atom (PKA) energies and temperatures.

Nandipati, Giridhar; Setyawan, Wahyu; Heinisch, Howard L.; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

2013-09-30T23:59:59.000Z

194

A Wigner Monte Carlo approach to density functional theory  

SciTech Connect (OSTI)

In order to simulate quantum N-body systems, stationary and time-dependent density functional theories rely on the capacity of calculating the single-electron wave-functions of a system from which one obtains the total electron density (Kohn–Sham systems). In this paper, we introduce the use of the Wigner Monte Carlo method in ab-initio calculations. This approach allows time-dependent simulations of chemical systems in the presence of reflective and absorbing boundary conditions. It also enables an intuitive comprehension of chemical systems in terms of the Wigner formalism based on the concept of phase-space. Finally, being based on a Monte Carlo method, it scales very well on parallel machines paving the way towards the time-dependent simulation of very complex molecules. A validation is performed by studying the electron distribution of three different systems, a Lithium atom, a Boron atom and a hydrogenic molecule. For the sake of simplicity, we start from initial conditions not too far from equilibrium and show that the systems reach a stationary regime, as expected (despite no restriction is imposed in the choice of the initial conditions). We also show a good agreement with the standard density functional theory for the hydrogenic molecule. These results demonstrate that the combination of the Wigner Monte Carlo method and Kohn–Sham systems provides a reliable computational tool which could, eventually, be applied to more sophisticated problems.

Sellier, J.M., E-mail: jeanmichel.sellier@gmail.com; Dimov, I.

2014-08-01T23:59:59.000Z

195

Projectile containing metastable intermolecular composites and spot fire method of use  

DOE Patents [OSTI]

A method for altering the course of a conflagration involving firing a projectile comprising a powder mixture of oxidant powder and nanosized reductant powder at velocity sufficient for a violent reaction between the oxidant powder and the nanosized reductant powder upon impact of the projectile, and causing impact of the projectile at a location chosen to draw a main fire to a spot fire at such location and thereby change the course of the conflagration, whereby the air near the chosen location is heated to a temperature sufficient to cause a spot fire at such location. The invention also includes a projectile useful for such method and said mixture preferably comprises a metastable intermolecular composite.

Asay, Blaine W.; Son, Steven F.; Sanders, V. Eric; Foley, Timothy; Novak, Alan M.; Busse, James R.

2012-07-31T23:59:59.000Z

196

Spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB  

DOE Patents [OSTI]

A simple, sensitive and specific spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB, is described. Upon the application of the composition of matter of the present invention to samples containing in excess of 0.1 mg of this explosive, a bright orange color results. Interfering species such as TNT and Tetryl can be removed by first treating the sample with a solvent which does not dissolve much of the TATB, but readily dissolves these explosives.

Harris, Betty W. (Los Alamos, NM)

1986-01-01T23:59:59.000Z

197

Spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB  

DOE Patents [OSTI]

A simple, sensitive and specific spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB, is described. Upon the application of the composition of matter of the subject invention to samples containing in excess of 0.1 mg of this explosive, a bright orange color results. Interfering species such as TNT and Tetryl can be removed by first treating the sample with a solvent which does not dissolve the TATB, but readily dissolves these interfering explosives.

Harris, B.W.

1984-11-29T23:59:59.000Z

198

Eutectic structures in friction spot welding joint of aluminum alloy to copper  

SciTech Connect (OSTI)

A dissimilar joint of AA5083 Al alloy and copper was produced by friction spot welding. The Al-MgCuAl{sub 2} eutectic in both coupled and divorced manners were found in the weld. At a relatively high temperature, mass transport of Cu due to plastic deformation, material flow, and atomic diffusion, combined with the alloy system of AA5083 are responsible for the ternary eutectic melting.

Shen, Junjun, E-mail: junjun.shen@hzg.de; Suhuddin, Uceu F. H.; Cardillo, Maria E. B.; Santos, Jorge F. dos [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Materials Mechanics, Solid-State Joining Processes, Max-Planck-Str. 1, 21502 Geesthacht (Germany)

2014-05-12T23:59:59.000Z

199

Characteristics of elliptical sources in BEAMnrc Monte Carlo system: Implementation and application  

SciTech Connect (OSTI)

Recently, several papers noticed that the electron focal spot of a linear accelerator (linac) could be elliptical which would cause dosimetric discrepancies between measurements and Monte Carlo simulations. To resolve the mismatch, two elliptical source models were developed in BEAMnrc code. The first was a parallel beam elliptical source with uniform distribution where the shape of the source was primarily considered. The other was a parallel beam elliptical source with Gaussian distribution whose source distribution follows the normal distribution. To validate the elliptical source models, uniform and Gaussian electron beams were impinged on a thin air target. Both models successfully reproduced the elliptical shapes and source distributions. Then, this study investigated the characteristics of the elliptical Gaussian source for a 6 MV photon beam in a Varian 21EX linac. The linac head model was implemented in the BEAMnrc/EGSnrc system and commissioned by comparing the lateral and depth dose profiles to the ion chamber measurements acquired from the annual quality assurance (QA). It was found that the circular Gaussian beam with 6 MeV/0.2 cm full width half maximum (FWHM) produces the best matches to the QA data. To explore the characteristics of the elliptical Gaussian source, this study employed an elliptical Gaussian electron source with 0.1 cm FWHM in the x axis and 0.2 cm FWHM in the y axis which was incident on the target of the linac head. Two circular Gaussian beams with 0.1 and 0.2 cm FWHM were employed to compare the differences between circular and elliptical sources. For all the sources, planar and energy fluences were acquired and analyzed. This study also compared the lateral and depth dose profiles in a water phantom by using a DOSXYZnrc user code. In results, a constricted shoulder effect was observed in both planar and energy fluence plots when the FWHM value was increased and the field size is larger than 30x30 cm{sup 2}. The same effect was also noticed in the lateral dose profiles, while the depth dose profile did not vary much.

Kim, Sangroh [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States)

2009-04-15T23:59:59.000Z

200

Friction Stir Spot Welding (FSSW) of Advanced High Strength Steel (AHSS)  

SciTech Connect (OSTI)

Friction stir spot welding (FSSW) is applied to join advanced high strength steels (AHSS): galvannealed dual phase 780 MPa steel (DP780GA), transformation induced plasticity 780 MPa steel (TRIP780), and hot-stamped boron steel (HSBS). A low-cost Si3N4 ceramic tool was developed and used for making welds in this study instead of polycrystalline cubic boron nitride (PCBN) material used in earlier studies. FSSW has the advantages of solid-state, low-temperature process, and the ability of joining dissimilar grade of steels and thicknesses. Two different tool shoulder geometries, concave with smooth surface and convex with spiral pattern, were used in the study. Welds were made by a 2-step displacement control process with weld time of 4, 6, and 10 seconds. Static tensile lap-shear strength achieved 16.4 kN for DP780GA-HSBS and 13.2kN for TRIP780-HSBS, above the spot weld strength requirements by AWS. Nugget pull-out was the failure mode of the joint. The joining mechanism was illustrated from the cross-section micrographs. Microhardness measurement showed hardening in the upper sheet steel (DP780GA or TRIP780) in the weld, but softening of HSBS in the heat-affect zone (HAZ). The study demonstrated the feasibility of making high-strength AHSS spot welds with low-cost tools.

Santella, M. L.; Hovanski, Yuri; Pan, Tsung-Yu

2012-04-16T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Blind Spots for neutralino Dark Matter in the MSSM with an intermediate m_A  

E-Print Network [OSTI]

We study the spin-independent neutralino Dark Matter scattering off heavy nuclei in the MSSM. We identify analytically the blind spots in direct detection for intermediate values of $m_A$. In the region where $\\mu$ and $M_{1,2}$ have opposite signs, there is not only a reduction of the lightest CP-even Higgs coupling to neutralinos, but also a destructive interference between the neutralino scattering through the exchange of the lightest CP-even Higgs and that through the exchange of the heaviest CP-even Higgs. At critical values of $m_A$, the tree-level contribution from the light Higgs exchange cancels the contribution from the heavy Higgs, so the scattering cross section vanishes. We denote these configurations as blind spots, since they provide a generalization of the ones previously discussed in the literature, which occur at very large values of $m_A$. We show that the generalized blind spots may occur in regions of parameter space that are consistent with the obtention of the proper neutralino relic density, and can be tested by non-standard Higgs boson searches and EWino searches at the LHC and future linear colliders.

Peisi Huang; Carlos E. M. Wagner

2014-07-01T23:59:59.000Z

202

A high resolution view of the jet termination shock in a hot spot of the nearby radio galaxy Pictor A: implications for X-ray models of radio galaxy hot spots  

E-Print Network [OSTI]

Images made with the VLBA have resolved the region in a nearby radio galaxy, Pictor A, where the relativistic jet that originates at the nucleus terminates in an interaction with the intergalactic medium, a so-called radio galaxy hot spot. This image provides the highest spatial resolution view of such an object to date (16 pc), more than three times better than previous VLBI observations of similar objects. The north-west Pictor A hot spot is resolved into a complex set of compact components, seen to coincide with the bright part of the hot spot imaged at arcsecond-scale resolution with the VLA. In addition to a comparison with VLA data, we compare our VLBA results with data from the HST and Chandra telescopes, as well as new Spitzer data. The presence of pc-scale components in the hot spot, identifying regions containing strong shocks in the fluid flow, leads us to explore the suggestion that they represent sites of synchrotron X-ray production, contributing to the integrated X-ray flux of the hot spot, along with X-rays from synchrotron self-Compton scattering. This scenario provides a natural explanation for the radio morphology of the hot spot and its integrated X-ray emission, leading to very different predictions for the higher energy X-ray spectrum compared to previous studies. From the sizes of the individual pc-scale components and their angular spread, we estimate that the jet width at the hot spot is in the range 70 - 700 pc, which is comparable to similar estimates in PKS 2153-69, 3C 205, and 4C 41.17. The lower limit in this range arises from the suggestion that the jet may dither in its direction as it passes through hot spot backflow material close to the jet termination point, creating a "dentist drill" effect on the inside of a cavity 700 pc in diameter.

S. J. Tingay; E. Lenc; G. Brunetti; M. Bondi

2008-10-02T23:59:59.000Z

203

Effect of Acidulated Phosphate Fluoride Gel on the Prevention of White Spot Lesions in Patients Undergoing Active Orthodontic Treatment  

E-Print Network [OSTI]

Introduction: The purpose of this study was to evaluate the effect of 1.23% acidulated phosphate fluoride (APF) gel on white spot lesion (WSL) formation utilizing a typical orthodontic treatment interval for the applications. Methods...

Hutto Fretty, Corneil Kimberly

2014-05-06T23:59:59.000Z

204

Managing Two-Spotted Spider Mites on Soybeans Ken Ostlie, Extension Entomologist, and Bruce Potter, IPM Specialist  

E-Print Network [OSTI]

Managing Two-Spotted Spider Mites on Soybeans Ken Ostlie, Extension Entomologist, and Bruce Potter? Spider mite populations are held in balance by natural enemies, weather and host quality. Drought

Minnesota, University of

205

Development of elastography as a non-invasive method for hard spots detection of packaged beef rations  

E-Print Network [OSTI]

generated under the selected conditions. The elastograms were segmented using an automatic thresholding algorithm and the results were used to analyze the detection of hard spots. The optimal conditions determined for elastography were an applied strain of 1...

Wang, Wei-wei

1998-01-01T23:59:59.000Z

206

Post-Harvest Control of Two-Spotted Spider Mites in Nikki Rothwell, District Fruit IPM Educator  

E-Print Network [OSTI]

with two distinct black spots; irregular dark splotches may appear after feeding. Male TSSM are more as both species can have greenish colored stages. TSSM infestations are often accompanied by silk webbing

207

Decision making in coastal fisheries conflict: the case of red drum and spotted seatrout legislation in Texas  

E-Print Network [OSTI]

Stricter Measures Called For The TPWD Increases Regulations on Red and Spotted Seatrout Illegal Netting 61 65 66 Drum TABLE OF CONTENTS (continued) IV CASE FINDINGS (continued) The Opposition Increases The Legislative Process Economic Impact... of the controversial House B i 1 1 1000 in the Texas Legislature. H B. 1000 was signed into law in May, 1981 and prohibits the possession or transportation for the purpose of sale red drum or spotted seatrout taken from waters under the jurisdiction of the state...

Christian, Richard Travis

1986-01-01T23:59:59.000Z

208

Properties of Reactive Oxygen Species by Quantum Monte Carlo  

E-Print Network [OSTI]

The electronic properties of the oxygen molecule, in its singlet and triplet states, and of many small oxygen-containing radicals and anions have important roles in different fields of Chemistry, Biology and Atmospheric Science. Nevertheless, the electronic structure of such species is a challenge for ab-initio computational approaches because of the difficulties to correctly describe the statical and dynamical correlation effects in presence of one or more unpaired electrons. Only the highest-level quantum chemical approaches can yield reliable characterizations of their molecular properties, such as binding energies, equilibrium structures, molecular vibrations, charge distribution and polarizabilities. In this work we use the variational Monte Carlo (VMC) and the lattice regularized Monte Carlo (LRDMC) methods to investigate the equilibrium geometries and molecular properties of oxygen and oxygen reactive species. Quantum Monte Carlo methods are used in combination with the Jastrow Antisymmetrized Geminal Power (JAGP) wave function ansatz, which has been recently shown to effectively describe the statical and dynamical correlation of different molecular systems. In particular we have studied the oxygen molecule, the superoxide anion, the nitric oxide radical and anion, the hydroxyl and hydroperoxyl radicals and their corresponding anions, and the hydrotrioxyl radical. Overall, the methodology was able to correctly describe the geometrical and electronic properties of these systems, through compact but fully-optimised basis sets and with a computational cost which scales as $N^3-N^4$, where $N$ is the number of electrons. This work is therefore opening the way to the accurate study of the energetics and of the reactivity of large and complex oxygen species by first principles.

Andrea Zen; Bernhardt L. Trout; Leonardo Guidoni

2014-03-11T23:59:59.000Z

209

Properties of reactive oxygen species by quantum Monte Carlo  

SciTech Connect (OSTI)

The electronic properties of the oxygen molecule, in its singlet and triplet states, and of many small oxygen-containing radicals and anions have important roles in different fields of chemistry, biology, and atmospheric science. Nevertheless, the electronic structure of such species is a challenge for ab initio computational approaches because of the difficulties to correctly describe the statical and dynamical correlation effects in presence of one or more unpaired electrons. Only the highest-level quantum chemical approaches can yield reliable characterizations of their molecular properties, such as binding energies, equilibrium structures, molecular vibrations, charge distribution, and polarizabilities. In this work we use the variational Monte Carlo (VMC) and the lattice regularized Monte Carlo (LRDMC) methods to investigate the equilibrium geometries and molecular properties of oxygen and oxygen reactive species. Quantum Monte Carlo methods are used in combination with the Jastrow Antisymmetrized Geminal Power (JAGP) wave function ansatz, which has been recently shown to effectively describe the statical and dynamical correlation of different molecular systems. In particular, we have studied the oxygen molecule, the superoxide anion, the nitric oxide radical and anion, the hydroxyl and hydroperoxyl radicals and their corresponding anions, and the hydrotrioxyl radical. Overall, the methodology was able to correctly describe the geometrical and electronic properties of these systems, through compact but fully-optimised basis sets and with a computational cost which scales as N{sup 3} ? N{sup 4}, where N is the number of electrons. This work is therefore opening the way to the accurate study of the energetics and of the reactivity of large and complex oxygen species by first principles.

Zen, Andrea [Dipartimento di Fisica, La Sapienza - Universitŕ di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Trout, Bernhardt L. [Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, Massachusetts 02139 (United States); Guidoni, Leonardo, E-mail: leonardo.guidoni@univaq.it [Dipartimento di Scienze Fisiche e Chimiche, Universitŕ degli studi de L'Aquila, Via Vetoio, 67100 Coppito, L'Aquila (Italy)

2014-07-07T23:59:59.000Z

210

Computational radiology and imaging with the MCNP Monte Carlo code  

SciTech Connect (OSTI)

MCNP, a 3D coupled neutron/photon/electron Monte Carlo radiation transport code, is currently used in medical applications such as cancer radiation treatment planning, interpretation of diagnostic radiation images, and treatment beam optimization. This paper will discuss MCNP`s current uses and capabilities, as well as envisioned improvements that would further enhance MCNP role in computational medicine. It will be demonstrated that the methodology exists to simulate medical images (e.g. SPECT). Techniques will be discussed that would enable the construction of 3D computational geometry models of individual patients for use in patient-specific studies that would improve the quality of care for patients.

Estes, G.P.; Taylor, W.M.

1995-05-01T23:59:59.000Z

211

Monte Carlo Simulations of the two-dimensional dipolar fluid  

E-Print Network [OSTI]

We study a two-dimensional fluid of dipolar hard disks by Monte Carlo simulations in a square with periodic boundary conditions and on the surface of a sphere. The theory of the dielectric constant and the asymptotic behaviour of the equilibrium pair correlation function in the fluid phase is derived for both geometries. After having established the equivalence of the two methods we study the stability of the liquid phase in the canonical ensemble. We give evidence of a phase made of living polymers at low temperatures and provide a tentative phase diagram.

Caillol, Jean-Michel

2015-01-01T23:59:59.000Z

212

GPU accelerated Monte Carlo simulations of lattice spin models  

E-Print Network [OSTI]

We consider Monte Carlo simulations of classical spin models of statistical mechanics using the massively parallel architecture provided by graphics processing units (GPUs). We discuss simulations of models with discrete and continuous variables, and using an array of algorithms ranging from single-spin flip Metropolis updates over cluster algorithms to multicanonical and Wang-Landau techniques to judge the scope and limitations of GPU accelerated computation in this field. For most simulations discussed, we find significant speed-ups by two to three orders of magnitude as compared to single-threaded CPU implementations.

Martin Weigel; Taras Yavors'kii

2011-07-27T23:59:59.000Z

213

Temperature and density extrapolations in canonical ensemble Monte Carlo simulations  

E-Print Network [OSTI]

We show how to use the multiple histogram method to combine canonical ensemble Monte Carlo simulations made at different temperatures and densities. The method can be applied to study systems of particles with arbitrary interaction potential and to compute the thermodynamic properties over a range of temperatures and densities. The calculation of the Helmholtz free energy relative to some thermodynamic reference state enables us to study phase coexistence properties. We test the method on the Lennard-Jones fluids for which many results are available.

A. L. Ferreira; M. A. Barroso

1999-06-14T23:59:59.000Z

214

Monte Carlo Tools for charged Higgs boson production  

E-Print Network [OSTI]

In this short review we discuss two implementations of the charged Higgs boson production process in association with a top quark in Monte Carlo event generators at next-to-leading order in QCD. We introduce the MC@NLO and the POWHEG method of matching next-to-leading order matrix elements with parton showers and compare both methods analyzing the charged Higgs boson production process in association with a top quark. We shortly discuss the case of a light charged Higgs boson where the associated charged Higgs production interferes with the charged Higgs production via t tbar-production and subsequent decay of the top quark.

K. Kovarik

2014-12-18T23:59:59.000Z

215

Adaptively Learning an Importance Function Using Transport Constrained Monte Carlo  

SciTech Connect (OSTI)

It is well known that a Monte Carlo estimate can be obtained with zero-variance if an exact importance function for the estimate is known. There are many ways that one might iteratively seek to obtain an ever more exact importance function. This paper describes a method that has obtained ever more exact importance functions that empirically produce an error that is dropping exponentially with computer time. The method described herein constrains the importance function to satisfy the (adjoint) Boltzmann transport equation. This constraint is provided by using the known form of the solution, usually referred to as the Case eigenfunction solution.

Booth, T.E.

1998-06-22T23:59:59.000Z

216

Bounded limit for the Monte Carlo point-flux-estimator  

SciTech Connect (OSTI)

In a Monte Carlo random walk the kernel K(R,E) is used as an expected value estimator at every collision for the collided flux phi/sub c/ r vector,E) at the detector point. A limiting value for the kernel is derived from a diffusion approximation for the probability current at a radius R/sub 1/ from the detector point. The variance of the collided flux at the detector point is thus bounded using this asymptotic form for K(R,E). The bounded point flux estimator is derived. (WHK)

Grimesey, R.A.

1981-01-01T23:59:59.000Z

217

Burnup calculation methodology in the serpent 2 Monte Carlo code  

SciTech Connect (OSTI)

This paper presents two topics related to the burnup calculation capabilities in the Serpent 2 Monte Carlo code: advanced time-integration methods and improved memory management, accomplished by the use of different optimization modes. The development of the introduced methods is an important part of re-writing the Serpent source code, carried out for the purpose of extending the burnup calculation capabilities from 2D assembly-level calculations to large 3D reactor-scale problems. The progress is demonstrated by repeating a PWR test case, originally carried out in 2009 for the validation of the newly-implemented burnup calculation routines in Serpent 1. (authors)

Leppaenen, J. [VTT Technical Research Centre of Finland, P.O.Box 1000, FI-02044 VTT (Finland); Isotalo, A. [Aalto Univ., Dept. of Applied Physics, P.O.Box 14100, FI-00076 AALTO (Finland)

2012-07-01T23:59:59.000Z

218

Global neutrino parameter estimation using Markov Chain Monte Carlo  

E-Print Network [OSTI]

We present a Markov Chain Monte Carlo global analysis of neutrino parameters using both cosmological and experimental data. Results are presented for the combination of all presently available data from oscillation experiments, cosmology, and neutrinoless double beta decay. In addition we explicitly study the interplay between cosmological, tritium decay and neutrinoless double beta decay data in determining the neutrino mass parameters. We furthermore discuss how the inference of non-neutrino cosmological parameters can benefit from future neutrino mass experiments such as the KATRIN tritium decay experiment or neutrinoless double beta decay experiments.

Steen Hannestad

2007-10-10T23:59:59.000Z

219

Continuous-Estimator Representation for Monte Carlo Criticality Diagnostics  

SciTech Connect (OSTI)

An alternate means of computing diagnostics for Monte Carlo criticality calculations is proposed. Overlapping spherical regions or estimators are placed covering the fissile material with a minimum center-to-center separation of the 'fission distance', which is defined herein, and a radius that is some multiple thereof. Fission neutron production is recorded based upon a weighted average of proximities to centers for all the spherical estimators. These scores are used to compute the Shannon entropy, and shown to reproduce the value, to within an additive constant, determined from a well-placed mesh by a user. The spherical estimators are also used to assess statistical coverage.

Kiedrowski, Brian C. [Los Alamos National Laboratory; Brown, Forrest B. [Los Alamos National Laboratory

2012-06-18T23:59:59.000Z

220

Investigation of Protein Folding by Using Combined Method of Molecular Dynamics and Monte Carlo Simulations.  

E-Print Network [OSTI]

??We used the combination of molecular dynamics and Monte Carlo method to investigate protein folding problems. The environments of proteins are very big, and often… (more)

Liao, Jun-min

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Protein folding and phylogenetic tree reconstruction using stochastic approximation Monte Carlo.  

E-Print Network [OSTI]

??Recently, the stochastic approximation Monte Carlo algorithm has been proposed by Liang et al. (2005) as a general-purpose stochastic optimization and simulation algorithm. An annealing… (more)

Cheon, Sooyoung

2007-01-01T23:59:59.000Z

222

E-Print Network 3.0 - all-atom monte carlo Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Population Monte Carlo and adaptive sampling... schemes Outline 1 Crash ... Source: Robert, Christian P. - Centre De Recherche en Mathmatiques de la Dcision, Universit...

223

E-Print Network 3.0 - adjoint monte carlo Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and finite-difference solving algorithms and Monte Carlo ensemble generation... INVERSE PROBLEMS Waveform-based seismic adjoint tomography, validation of global and regional...

224

Monte Carlo source convergence and the Whitesides problem  

SciTech Connect (OSTI)

The issue of fission source convergence in Monte Carlo eigenvalue calculations is of interest because of the potential consequences of erroneous criticality safety calculations. In this work, the authors compare two different techniques to improve the source convergence behavior of standard Monte Carlo calculations applied to challenging source convergence problems. The first method, super-history powering, attempts to avoid discarding important fission sites between generations by delaying stochastic sampling of the fission site bank until after several generations of multiplication. The second method, stratified sampling of the fission site bank, explicitly keeps the important sites even if conventional sampling would have eliminated them. The test problems are variants of Whitesides' Criticality of the World problem in which the fission site phase space was intentionally undersampled in order to induce marginally intolerable variability in local fission site populations. Three variants of the problem were studied, each with a different degree of coupling between fissionable pieces. Both the superhistory powering method and the stratified sampling method were shown to improve convergence behavior, although stratified sampling is more robust for the extreme case of no coupling. Neither algorithm completely eliminates the loss of the most important fissionable piece, and if coupling is absent, the lost piece cannot be recovered unless its sites from earlier generations have been retained. Finally, criteria for measuring source convergence reliability are proposed and applied to the test problems.

Blomquist, R. N.

2000-02-25T23:59:59.000Z

225

Stratified source-sampling techniques for Monte Carlo eigenvalue analysis.  

SciTech Connect (OSTI)

In 1995, at a conference on criticality safety, a special session was devoted to the Monte Carlo ''Eigenvalue of the World'' problem. Argonne presented a paper, at that session, in which the anomalies originally observed in that problem were reproduced in a much simplified model-problem configuration, and removed by a version of stratified source-sampling. In this paper, stratified source-sampling techniques are generalized and applied to three different Eigenvalue of the World configurations which take into account real-world statistical noise sources not included in the model problem, but which differ in the amount of neutronic coupling among the constituents of each configuration. It is concluded that, in Monte Carlo eigenvalue analysis of loosely-coupled arrays, the use of stratified source-sampling reduces the probability of encountering an anomalous result over that if conventional source-sampling methods are used. However, this gain in reliability is substantially less than that observed in the model-problem results.

Mohamed, A.

1998-07-10T23:59:59.000Z

226

Improved criticality convergence via a modified Monte Carlo iteration method  

SciTech Connect (OSTI)

Nuclear criticality calculations with Monte Carlo codes are normally done using a power iteration method to obtain the dominant eigenfunction and eigenvalue. In the last few years it has been shown that the power iteration method can be modified to obtain the first two eigenfunctions. This modified power iteration method directly subtracts out the second eigenfunction and thus only powers out the third and higher eigenfunctions. The result is a convergence rate to the dominant eigenfunction being |k{sub 3}|/k{sub 1} instead of |k{sub 2}|/k{sub 1}. One difficulty is that the second eigenfunction contains particles of both positive and negative weights that must sum somehow to maintain the second eigenfunction. Summing negative and positive weights can be done using point detector mechanics, but this sometimes can be quite slow. We show that an approximate cancellation scheme is sufficient to accelerate the convergence to the dominant eigenfunction. A second difficulty is that for some problems the Monte Carlo implementation of the modified power method has some stability problems. We also show that a simple method deals with this in an effective, but ad hoc manner.

Booth, Thomas E [Los Alamos National Laboratory; Gubernatis, James E [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

227

Monte Carlo simulation of quantum Zeno effect in the brain  

E-Print Network [OSTI]

Environmental decoherence appears to be the biggest obstacle for successful construction of quantum mind theories. Nevertheless, the quantum physicist Henry Stapp promoted the view that the mind could utilize quantum Zeno effect to influence brain dynamics and that the efficacy of such mental efforts would not be undermined by environmental decoherence of the brain. To address the physical plausibility of Stapp's claim, we modeled the brain using quantum tunneling of an electron in a multiple-well structure such as the voltage sensor in neuronal ion channels and performed Monte Carlo simulations of quantum Zeno effect exerted by the mind upon the brain in the presence or absence of environmental decoherence. The simulations unambiguously showed that the quantum Zeno effect breaks down for timescales greater than the brain decoherence time. To generalize the Monte Carlo simulation results for any n-level quantum system, we further analyzed the change of brain entropy due to the mind probing actions and proved a theorem according to which local projections cannot decrease the von Neumann entropy of the unconditional brain density matrix. The latter theorem establishes that Stapp's model is physically implausible but leaves a door open for future development of quantum mind theories provided the brain has a decoherence-free subspace.

Danko Georgiev

2014-12-11T23:59:59.000Z

228

Resistance spot welding of ultra-fine grained steel sheets produced by constrained groove pressing: Optimization and characterization  

SciTech Connect (OSTI)

Constrained groove pressing as a severe plastic deformation method is utilized to produce ultra-fine grained low carbon steel sheets. The ultra-fine grained sheets are joined via resistance spot welding process and the characteristics of spot welds are investigated. Resistance spot welding process is optimized for welding of the sheets with different severe deformations and their results are compared with those of as-received samples. The effects of failure mode and expulsion on the performance of ultra-fine grained sheet spot welds have been investigated in the present paper and the welding current and time of resistance spot welding process according to these subjects are optimized. Failure mode and failure load obtained in tensile-shear test, microhardness, X-ray diffraction, transmission electron microscope and scanning electron microscope images have been used to describe the performance of spot welds. The region between interfacial to pullout mode transition and expulsion limit is defined as the optimum welding condition. The results show that optimum welding parameters (welding current and welding time) for ultra-fine grained sheets are shifted to lower values with respect to those for as-received specimens. In ultra-fine grained sheets, one new region is formed named recrystallized zone in addition to fusion zone, heat affected zone and base metal. It is shown that microstructures of different zones in ultra-fine grained sheets are finer than those of as-received sheets. - Highlights: Black-Right-Pointing-Pointer Resistance spot welding process is optimized for joining of UFG steel sheets. Black-Right-Pointing-Pointer Optimum welding current and time are decreased with increasing the CGP pass number. Black-Right-Pointing-Pointer Microhardness at BM, HAZ, FZ and recrystallized zone is enhanced due to CGP.

Khodabakhshi, F.; Kazeminezhad, M., E-mail: mkazemi@sharif.edu; Kokabi, A.H.

2012-07-15T23:59:59.000Z

229

Resistance Spot Welding of Aluminum Alloy to Steel with Transition Material - From Process to Performance  

SciTech Connect (OSTI)

This paper summarizes work to date on resistance spot welding (RSW) of aluminum alloy to mild steel from process development to performance evaluation. A cold-rolled strip material is introduced as a transition material to aid the resistance welding process. The optimal welding parameters and electrode selections were established using a combination of experimental and analytical approaches. The mechanical behaviors of welded samples was evaluated using static and dynamic strength tests and cyclic fatigue tests. A statistical analysis was also performed to analyze the effect of different failure modes on the sample's peak load and energy absorption.

Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.; Shao, H; Kimchi, Menachem; Menachem Kimchi and Wanda Newman

2004-05-11T23:59:59.000Z

230

Numerical studies of third-harmonic generation in laser filament in air perturbed by plasma spot  

SciTech Connect (OSTI)

Third-harmonic emission from laser filament intercepted by plasma spot is studied by numerical simulations. Significant enhancement of the third-harmonic generation is obtained due to the disturbance of the additional plasma. The contribution of the pure plasma effect and the possible plasma-enhanced third-order susceptibility on the third-harmonic generation enhancement are compared. It is shown that the plasma induced cancellation of destructive interference [Y. Liu et al., Opt. Commun. 284, 4706 (2011)] of two-colored filament is the dominant mechanism of the enhancement of third-harmonic generation.

Feng Liubin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Institute of Atomic and Molecular Physics and Department of Physics, Sichuan University, Chengdu 610065 (China); Lu Xin; Liu Xiaolong; Li Yutong; Chen Liming; Ma Jinglong; Dong Quanli; Wang Weimin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Xi Tingting [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Sheng Zhengming; Zhang Jie [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Key Laboratory for Laser Plasmas of the Ministry of Education of China and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); He Duanwei [Institute of Atomic and Molecular Physics and Department of Physics, Sichuan University, Chengdu 610065 (China)

2012-07-15T23:59:59.000Z

231

The Influence of spot size on the expansion dynamics of nanosecond-laser-produced copper plasmas in atmosphere  

SciTech Connect (OSTI)

Laser produced copper plasmas of different spot sizes in air were investigated using fast photography and optical emission spectroscopy (OES). The laser energy was 33 mJ. There were dramatic changes in the plasma plume expansion into the ambient air when spot sizes changed from {approx}0.1 mm to {approx}0.6 mm. A stream-like structure and a hemispherical structure were, respectively, observed. It appeared that the same spot size resulted in similar expansion dynamics no matter whether the target was located in the front of or behind the focal point, although laser-induced air breakdown sometimes occurred in the latter case. Plasma plume front positions agree well with the classic blast wave model for the large spot-size cases, while an unexpected stagnation of {approx}80 ns occurred after the laser pulse ends for the small spot size cases. This stagnation can be understood in terms of the evolution of enhanced plasma shielding effects near the plasma front. Axial distributions of plasma components by OES revealed a good confinement effect. Electron number densities were estimated and interpreted using the recorded Intensified Charge Coupled Device (ICCD) images.

Li, Xingwen; Wei, Wenfu; Wu, Jian; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 XianNing West Road, Xi'an, Shaanxi Province 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 XianNing West Road, Xi'an, Shaanxi Province 710049 (China)

2013-06-28T23:59:59.000Z

232

Wear testing of friction stir spot welding tools for joining of DP 980 Steel  

SciTech Connect (OSTI)

Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel (UHSS), both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Several tooling materials have been evaluated in prior studies, including silicon nitride and polycrystalline cubic boron nitride (PCBN). Recently a new tool alloy has been developed, where a blend of PCBN and tungsten rhenium (W-Re) was used in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W-Re (designated as Q60), and one with 70% PCBN and 30% W-Re (designated at Q70). The sheet material used for all wear testing was DP 980. Tool profiles were measured periodically during the testing process in order to show the progression of wear as a function of the number of spots produced. Lap shear testing was done each time a tool profile was taken in order to show the relationship between tool wear and joint strength. For the welding parameters chosen for this study the Q70 tool provided the best combination of wear resistance and joint strength.

Ridges, Chris; Miles, Michael; Hovanski, Yuri; Peterson, Jeremy; Steel, Russell

2011-06-06T23:59:59.000Z

233

Joint strength in high speed friction stir spot welded DP 980 steel  

SciTech Connect (OSTI)

High speed friction stir spot welding was applied to 1.2 mm thick DP 980 steel sheets under different welding conditions, using PCBN tools. The range of vertical feed rates used during welding was 2.5 mm – 102 mm per minute, while the range of spindle speeds was 2500 – 6000 rpm. Extended testing was carried out for five different sets of welding conditions, until tool failure. These welding conditions resulted in vertical welding loads of 3.6 – 8.2 kN and lap shear tension failure loads of 8.9 – 11.1 kN. PCBN tools were shown, in the best case, to provide lap shear tension fracture loads at or above 9 kN for 900 spot welds, after which tool failure caused a rapid drop in joint strength. Joint strength was shown to be strongly correlated to bond area, which was measured from weld cross sections. Failure modes of the tested joints were a function of bond area and softening that occurred in the heat-affected zone.

Saunders, Nathan; Miles, Michael; Hartman, Trent; Hovanski, Yuri; Hong, Sung Tae; Steel, Russell

2014-05-01T23:59:59.000Z

234

Monitoring seasonal and annual wetland changes in a freshwater marsh with SPOT HRV data  

SciTech Connect (OSTI)

Eleven dates of SPOT HRV data along with near-concurrent vertical aerial photographic and phenological data for 1987, 1988, and 1989 were evaluated to determine seasonal and annual changes in a 400-hectare, southeastern freshwater marsh. Early April through mid-May was the best time to discriminate among the cypress (Taxodium distichum)/water tupelo (Nyssa acquatica) swamp forest and the non-persistent (Ludwigia spp.) and persistent (Typha spp.) stands in this wetlands. Furthermore, a ten-fold decrease in flow rate from 11 cubic meters per sec (cms) in 1987 to one cms in 1988 was recorded in the marsh followed by a shift to drier wetland communities. The Savannah River Site (SRS), maintained by the US Department of Energy, is a 777 km{sup 2} area located in south central South Carolina. Five tributaries of the Savannah River run southwest through the SRS and into the floodplain swamp of the Savannah River. This paper describes the use of SPOT HRV data to monitor seasonal and annual trends in one of these swamp deltas, Pen Branch Delta, during a three-year period, 1987--1989.

Mackey, H.E. Jr.

1989-01-01T23:59:59.000Z

235

Monitoring seasonal and annual wetland changes in a freshwater marsh with SPOT HRV data  

SciTech Connect (OSTI)

Eleven dates of SPOT HRV data along with near-concurrent vertical aerial photographic and phenological data for 1987, 1988, and 1989 were evaluated to determine seasonal and annual changes in a 400-hectare, southeastern freshwater marsh. Early April through mid-May was the best time to discriminate among the cypress (Taxodium distichum)/water tupelo (Nyssa acquatica) swamp forest and the non-persistent (Ludwigia spp.) and persistent (Typha spp.) stands in this wetlands. Furthermore, a ten-fold decrease in flow rate from 11 cubic meters per sec (cms) in 1987 to one cms in 1988 was recorded in the marsh followed by a shift to drier wetland communities. The Savannah River Site (SRS), maintained by the US Department of Energy, is a 777 km{sup 2} area located in south central South Carolina. Five tributaries of the Savannah River run southwest through the SRS and into the floodplain swamp of the Savannah River. This paper describes the use of SPOT HRV data to monitor seasonal and annual trends in one of these swamp deltas, Pen Branch Delta, during a three-year period, 1987--1989.

Mackey, H.E. Jr.

1989-12-31T23:59:59.000Z

236

DEFINING THE 'BLIND SPOT' OF HINODE EIS AND XRT TEMPERATURE MEASUREMENTS  

SciTech Connect (OSTI)

Observing high-temperature, low emission measure plasma is key to unlocking the coronal heating problem. With current instrumentation, a combination of EUV spectral data from Hinode Extreme-ultraviolet Imaging Spectrometer (EIS; sensitive to temperatures up to 4 MK) and broadband filter data from Hinode X-ray Telescope (XRT; sensitive to higher temperatures) is typically used to diagnose the temperature structure of the observed plasma. In this Letter, we demonstrate that a 'blind spot' exists in temperature-emission measure space for combined Hinode EIS and XRT observations. For a typical active region core with significant emission at 3-4 MK, Hinode EIS and XRT are insensitive to plasma with temperatures greater than {approx}6 MK and emission measures less than {approx}10{sup 27} cm{sup -5}. We then demonstrate that the temperature and emission measure limits of this blind spot depend upon the temperature distribution of the plasma along the line of sight by considering a hypothetical emission measure distribution sharply peaked at 1 MK. For this emission measure distribution, we find that EIS and XRT are insensitive to plasma with emission measures less than {approx}10{sup 26} cm{sup -5}. We suggest that a spatially and spectrally resolved 6-24 Angstrom-Sign spectrum would improve the sensitivity to these high-temperature, low emission measure plasma.

Winebarger, Amy R.; Cirtain, Jonathan; Mulu-Moore, Fana [NASA Marshall Space Flight Center, VP 62, Huntsville, AL 35812 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Schmelz, Joan T. [Physics Department, University of Memphis, Memphis, TN 38152 (United States); Golub, Leon [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kobayashi, Ken, E-mail: amy.r.winebarger@nasa.gov [Center for Space Plasma and Aeronomic Research, 320 Sparkman Dr, Huntsville, AL 35805 (United States)

2012-02-20T23:59:59.000Z

237

Optimization of quantum Monte Carlo wave functions using analytical energy derivatives  

E-Print Network [OSTI]

Optimization of quantum Monte Carlo wave functions using analytical energy derivatives Xi Lin of the local energy, H^ / .5 If the wave function were the exact ground eigenstate, the local energy would November 1999 An algorithm is proposed to optimize quantum Monte Carlo QMC wave functions based on Newton

Lin, Xi

238

Status of the VIM Monte Carlo neutron/photon transport code.  

SciTech Connect (OSTI)

Recent work on the VIM Monte Carlo code has aimed at advanced data libraries, ease of use, availability to users outside of Argonne, and fission source convergence algorithms in eigenvalue calculations. VIM is one of three US Monte Carlo codes in the USDOE Nuclear Criticality Safety Program, and is available through RSICC and the NEA Data Bank.

Blomquist, R.N.

2002-01-22T23:59:59.000Z

239

Improved quantum Monte Carlo calculation of the ground-state energy of the hydrogen molecule  

E-Print Network [OSTI]

variational energies. The accuracy of the new Monte Carlo energy is approximately equal to that of recentImproved quantum Monte Carlo calculation of the ground-state energy of the hydrogen molecule Bin Carlo calculation of the nonrelativistic ground-state energy of the hydrogen molecule, without the use

Anderson, James B.

240

Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense Helium  

E-Print Network [OSTI]

Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense integral Monte Carlo (PIMC) and density func- tional molecular dynamics (DFT-MD), are applied to study hot excitation mecha- nisms that determine their behavior at high temperature. The helium atom has two ionization

Militzer, Burkhard

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Tuning Green's Function Monte Carlo for Mira Steven C. Pieper, Physics Division, Argonne National Laboratory  

E-Print Network [OSTI]

Tuning Green's Function Monte Carlo for Mira Steven C. Pieper, Physics Division, Argonne National Laboratory Partners in crime Ralph Butler (Middle Tennessee State) Joseph Carlson (Los Alamos) Stefano for comparisons of models to data · Quantum Monte Carlo has made much progress for A 12 · Nuclei go up to A=238

Kemner, Ken

242

A new quasi-Monte Carlo technique based on nonnegative least squares and  

E-Print Network [OSTI]

A new quasi-Monte Carlo technique based on nonnegative least squares and approximate Fekete points Claudia Bittantea , Stefano De Marchia, , Alvise Sommarivaa aUniversity of Padova, Department of the quasi-Monte Carlo method. The method, simple in its formulation, be- comes computationally inefficient

De Marchi, Stefano

243

Melting of Iron under Earth's Core Conditions from Diffusion Monte Carlo Free Energy Calculations  

E-Print Network [OSTI]

Melting of Iron under Earth's Core Conditions from Diffusion Monte Carlo Free Energy Calculations Ester Sola1 and Dario Alfe`1,2 1 Thomas Young Centre@UCL, and Department of Earth Sciences, UCL, Gower. Here we used quantum Monte Carlo techniques to compute the free energies of solid and liquid iron

Alfè, Dario

244

Density functional and Monte Carlo studies of sulfur. II. Equilibrium polymerization of the liquid phase  

E-Print Network [OSTI]

Density functional and Monte Carlo studies of sulfur. II. Equilibrium polymerization of the liquid 7 July 2003; accepted 28 July 2003 The equilibrium polymerization of sulfur is investigated by Monte), within which polymerization occurs readily, with entropy from the bond distribution overcompensating

245

On Filtering the Noise from the Random Parameters in Monte Carlo Rendering  

E-Print Network [OSTI]

On Filtering the Noise from the Random Parameters in Monte Carlo Rendering PRADEEP SEN and SOHEIL DARABI UNM Advanced Graphics Lab Monte Carlo (MC) rendering systems can produce spectacular images from a small number of input samples. To do this, we treat the rendering system as a black box

Sen, Pradeep

246

Monte Carlo simulations of free chains in end-linked polymer networks Nisha Gilra  

E-Print Network [OSTI]

be significantly altered.1­3 This occurs because the micro- scopic structure including network defectsMonte Carlo simulations of free chains in end-linked polymer networks Nisha Gilra School networks prepared in the presence of inert linear chain solvent were investigated with Monte Carlo

247

Self-assembly of surfactants in a supercritical solvent from lattice Monte Carlo simulations  

E-Print Network [OSTI]

Self-assembly of surfactants in a supercritical solvent from lattice Monte Carlo simulations Martin self-assembly of surfactants in a supercritical solvent by large-scale Monte Carlo simulations. CarbonCO2.3 Surfactant molecules used in scCO2 have two mutually incompatible components: a CO2-philic tail

Lisal, Martin

248

Effect of different genotypes of Phytophthora infestans (Mont. de Bary) and temperature on tuber disease development  

E-Print Network [OSTI]

Effect of different genotypes of Phytophthora infestans (Mont. de Bary) and temperature on tuber Lines (ABL) of potato with different genotypes of the potato late blight pathogen (Phytophthora Phytophthora infestans (Mont. de Bary) is the greatest threat to the potato crop, accounting for significant

Douches, David S.

249

Quantum Monte Carlo study of a disordered 2D Josephson junction array  

E-Print Network [OSTI]

Quantum Monte Carlo study of a disordered 2D Josephson junction array W.A. Al-Saidi *, D. Stroud reserved. PACS: 74.25.Dw; 05.30.Jp; 85.25.Cp Keywords: Josephson junctions; Quantum Monte Carlo; Disorder 1. Introduction A Josephson junction array (JJA) consists of a collection of superconducting islands connected

Stroud, David

250

Monte Carlo Methods for Uncertainty Quantification Mathematical Institute, University of Oxford  

E-Print Network [OSTI]

methods October 25, 2013 7 / 28 Application 3 In modelling groundwater flow in nuclear waste repositories: Introduction and Monte Carlo basics some model applications random number generation Monte Carlo estimation specified range Note: if we turn this into a full finite element analysis, then the computational cost

Giles, Mike

251

Hydrogen molecule ion: Path-integral Monte Carlo approach  

SciTech Connect (OSTI)

The path-integral Monte Carlo approach is used to study the coupled quantum dynamics of the electron and nuclei in hydrogen molecule ion. The coupling effects are demonstrated by comparing differences in adiabatic Born-Oppenheimer and nonadiabatic simulations, and inspecting projections of the full three-body dynamics onto the adiabatic Born-Oppenheimer approximation. Coupling of the electron and nuclear quantum dynamics is clearly seen. The nuclear pair correlation function is found to broaden by 0.040a{sub 0}, and the average bond length is larger by 0.056a{sub 0}. Also, a nonadiabatic correction to the binding energy is found. The electronic distribution is affected less than the nuclear one upon inclusion of nonadiabatic effects.

Kylaenpaeae, I.; Leino, M.; Rantala, T. T. [Institute of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland)

2007-11-15T23:59:59.000Z

252

Normality of Monte Carlo criticality eigenfunction decomposition coefficients  

SciTech Connect (OSTI)

A proof is presented, which shows that after a single Monte Carlo (MC) neutron transport power method iteration without normalization, the coefficients of an eigenfunction decomposition of the fission source density are normally distributed when using analog or implicit capture MC. Using a Pearson correlation coefficient test, the proof is corroborated by results from a uniform slab reactor problem, and those results also suggest that the coefficients are normally distributed with normalization. The proof and numerical test results support the application of earlier work on the convergence of eigenfunctions under stochastic operators. Knowledge of the Gaussian shape of decomposition coefficients allows researchers to determine an appropriate level of confidence in the distribution of fission sites taken from a MC simulation. This knowledge of the shape of the probability distributions of decomposition coefficients encourages the creation of new predictive convergence diagnostics. (authors)

Toth, B. E.; Martin, W. R. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Griesheimer, D. P. [Bechtel Bettis, Inc., P.O. Box 79, West Mifflin, PA 15122 (United States)

2013-07-01T23:59:59.000Z

253

Monte Carlo solution of a semi-discrete transport equation  

SciTech Connect (OSTI)

The authors present the S{sub {infinity}} method, a hybrid neutron transport method in which Monte Carlo particles traverse discrete space. The goal of any deterministic/stochastic hybrid method is to couple selected characters from each of the methods in hopes of producing a better method. The S{sub {infinity}} method has the features of the lumped, linear-discontinuous (LLD) spatial discretization, yet it has no ray-effects because of the continuous angular variable. They derive the S{sub {infinity}} method for the solid-state, mono-energetic transport equation in one-dimensional slab geometry with isotropic scattering and an isotropic internal source. They demonstrate the viability of the S{sub {infinity}} method by comparing their results favorably to analytic and deterministic results.

Urbatsch, T.J.; Morel, J.E.; Gulick, J.C.

1999-09-01T23:59:59.000Z

254

Velocity renormalization in graphene from lattice Monte Carlo  

E-Print Network [OSTI]

We compute the Fermi velocity of the Dirac quasiparticles in clean graphene at the charge neutrality point for strong Coulomb coupling alpha_g. We perform a Lattice Monte Carlo calculation within the low-energy Dirac theory, which includes an instantaneous, long-range Coulomb interaction. We find a renormalized Fermi velocity v_FR > v_F, where v_F = c/300. Our results are consistent with a momentum-independent v_FR which increases approximately linearly with alpha_g, although a logarithmic running with momentum cannot be excluded at present. At the predicted critical coupling alpha_gc for the semimetal-insulator transition due to excitonic pair formation, we find v_FR/v_F = 3.3, which we discuss in light of experimental findings for v_FR/v_F at the charge neutrality point in ultra-clean suspended graphene.

Joaquín E. Drut; Timo A. Lähde

2014-03-26T23:59:59.000Z

255

Quantum Monte Carlo study of inhomogeneous neutron matter  

E-Print Network [OSTI]

We present an ab-initio study of neutron drops. We use Quantum Monte Carlo techniques to calculate the energy up to 54 neutrons in different external potentials, and we compare the results with Skyrme forces. We also calculate the rms radii and radial densities, and we find that a re-adjustment of the gradient term in Skyrme is needed in order to reproduce the properties of these systems given by the ab-initio calculation. By using the ab-initio results for neutron drops for close- and open-shell configurations, we suggest how to improve Skyrme forces when dealing with systems with large isospin-asymmetries like neutron-rich nuclei.

Stefano Gandolfi

2012-08-31T23:59:59.000Z

256

The neutron instrument Monte Carlo library MCLIB: Recent developments  

SciTech Connect (OSTI)

A brief review is given of the developments since the ICANS-XIII meeting made in the neutron instrument design codes using the Monte Carlo library MCLIB. Much of the effort has been to assure that the library and the executing code MC{_}RUN connect efficiently with the World Wide Web application MC-WEB as part of the Los Alamos Neutron Instrument Simulation Package (NISP). Since one of the most important features of MCLIB is its open structure and capability to incorporate any possible neutron transport or scattering algorithm, this document describes the current procedure that would be used by an outside user to add a feature to MCLIB. Details of the calling sequence of the core subroutine OPERATE are discussed, and questions of style are considered and additional guidelines given. Suggestions for standardization are solicited, as well as code for new algorithms.

Seeger, P.A.; Daemen, L.L.; Hjelm, R.P. Jr.; Thelliez, T.G.

1998-12-31T23:59:59.000Z

257

Monte Carlo Simulation Tool Installation and Operation Guide  

SciTech Connect (OSTI)

This document provides information on software and procedures for Monte Carlo simulations based on the Geant4 toolkit, the ROOT data analysis software and the CRY cosmic ray library. These tools have been chosen for its application to shield design and activation studies as part of the simulation task for the Majorana Collaboration. This document includes instructions for installation, operation and modification of the simulation code in a high cyber-security computing environment, such as the Pacific Northwest National Laboratory network. It is intended as a living document, and will be periodically updated. It is a starting point for information collection by an experimenter, and is not the definitive source. Users should consult with one of the authors for guidance on how to find the most current information for their needs.

Aguayo Navarrete, Estanislao; Ankney, Austin S.; Berguson, Timothy J.; Kouzes, Richard T.; Orrell, John L.; Troy, Meredith D.; Wiseman, Clinton G.

2013-09-02T23:59:59.000Z

258

Synchronous parallel kinetic Monte Carlo Diffusion in Heterogeneous Systems  

SciTech Connect (OSTI)

A new hybrid Molecular Dynamics-kinetic Monte Carlo algorithm has been developed in order to study the basic mechanisms taking place in diffusion in concentrated alloys under the action of chemical and stress fields. Parallel implementation of the k-MC part based on a recently developed synchronous algorithm [1. Compo Phys. 227 (2008) 3804-3823] resorting on the introduction of a set of null events aiming at synchronizing the time for the different subdomains, added to the parallel efficiency of MD, provides the computer power required to evaluate jump rates 'on the flight', incorporating in this way the actual driving force emerging from chemical potential gradients, and the actual environment-dependent jump rates. The time gain has been analyzed and the parallel performance reported. The algorithm is tested on simple diffusion problems to verify its accuracy.

Martinez Saez, Enrique [Los Alamos National Laboratory; Hetherly, Jeffery [Los Alamos National Laboratory; Caro, Jose A [Los Alamos National Laboratory

2010-12-06T23:59:59.000Z

259

Atomistic Kinetic Monte Carlo Simulations of Polycrystalline Copper Electrodeposition  

E-Print Network [OSTI]

A high-fidelity kinetic Monte Carlo (KMC) simulation method (T. Treeratanaphitak, M. Pritzker, N. M. Abukhdeir, Electrochim. Acta 121 (2014) 407--414) using the semi-empirical multi-body embedded-atom method (EAM) potential has been extended to model polycrystalline metal electrodeposition. The presented KMC-EAM method enables true three-dimensional atomistic simulations of electrodeposition over experimentally relevant timescales. Simulations using KMC-EAM are performed over a range of overpotentials to predict the effect on deposit texture evolution. Results show strong agreement with past experimental results both with respect to deposition rates on various copper surfaces and roughness-time power law behaviour. It is found that roughness scales with time $\\propto t^\\beta$ where $\\beta=0.62 \\pm 0.12$, which is in good agreement with past experimental results. Furthermore, the simulations provide insights into sub-surface deposit morphologies which are not directly accessible from experimental measurements.

Treeratanaphitak, Tanyakarn; Abukhdeir, Nasser Mohieddin

2014-01-01T23:59:59.000Z

260

RMC - A Monte Carlo code for reactor physics analysis  

SciTech Connect (OSTI)

A new Monte Carlo neutron transport code RMC has been being developed by Department of Engineering Physics, Tsinghua University, Beijing as a tool for reactor physics analysis on high-performance computing platforms. To meet the requirements of reactor analysis, RMC now has such functions as criticality calculation, fixed-source calculation, burnup calculation and kinetics simulations. Some techniques for geometry treatment, new burnup algorithm, source convergence acceleration, massive tally and parallel calculation, and temperature dependent cross sections processing are researched and implemented in RMC to improve the efficiency. Validation results of criticality calculation, burnup calculation, source convergence acceleration, tallies performance and parallel performance shown in this paper prove the capabilities of RMC in dealing with reactor analysis problems with good performances. (authors)

Wang, K.; Li, Z.; She, D.; Liang, J.; Xu, Q.; Qiu, A.; Yu, J.; Sun, J.; Fan, X.; Yu, G. [Department of Engineering Physics, Tsinghua University, Liuqing Building, Beijing, 100084 (China)

2013-07-01T23:59:59.000Z

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261

Monte Carlo reactor calculation with substantially reduced number of cycles  

SciTech Connect (OSTI)

A new Monte Carlo (MC) eigenvalue calculation scheme that substantially reduces the number of cycles is introduced with the aid of coarse mesh finite difference (CMFD) formulation. First, it is confirmed in terms of pin power errors that using extremely many particles resulting in short active cycles is beneficial even in the conventional MC scheme although wasted operations in inactive cycles cannot be reduced with more particles. A CMFD-assisted MC scheme is introduced as an effort to reduce the number of inactive cycles and the fast convergence behavior and reduced inter-cycle effect of the CMFD assisted MC calculation is investigated in detail. As a practical means of providing a good initial fission source distribution, an assembly based few-group condensation and homogenization scheme is introduced and it is shown that efficient MC eigenvalue calculations with fewer than 20 total cycles (including inactive cycles) are possible for large power reactor problems. (authors)

Lee, M. J.; Joo, H. G. [Seoul National Univ., 599 Gwanak-ro, Gwanak-gu, Seoul, 151-744 (Korea, Republic of); Lee, D. [Ulsan National Inst. of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan, 689-798 (Korea, Republic of); Smith, K. [Massachusetts Inst. of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307 (United States)

2012-07-01T23:59:59.000Z

262

Monte Carlo modeling of spallation targets containing uranium and americium  

E-Print Network [OSTI]

Neutron production and transport in spallation targets made of uranium and americium are studied with a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems). A good agreement of MCADS results with experimental data on neutron- and proton-induced reactions on $^{241}$Am and $^{243}$Am nuclei allows to use this model for simulations with extended Am targets. Several geometry options and material compositions (U, U+Am, Am, Am$_2$O$_3$) are considered for spallation targets to be used in Accelerator Driven Systems. It was demonstrated that MCADS model can be reliably used for calculating critical masses of fissile materials. All considered options operate as deep subcritical targets having neutron multiplication factor of $k \\sim 0.5$. It is found that more than 4 kg of Am can be burned in one spallation target during the first year of operation.

Malyshkin, Yury; Mishustin, Igor; Greiner, Walter

2013-01-01T23:59:59.000Z

263

Monte Carlo modeling of spallation targets containing uranium and americium  

E-Print Network [OSTI]

Neutron production and transport in spallation targets made of uranium and americium are studied with a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems). A good agreement of MCADS results with experimental data on neutron- and proton-induced reactions on $^{241}$Am and $^{243}$Am nuclei allows to use this model for simulations with extended Am targets. It was demonstrated that MCADS model can be used for calculating the values of critical mass for $^{233,235}$U, $^{237}$Np, $^{239}$Pu and $^{241}$Am. Several geometry options and material compositions (U, U+Am, Am, Am$_2$O$_3$) are considered for spallation targets to be used in Accelerator Driven Systems. All considered options operate as deep subcritical targets having neutron multiplication factor of $k \\sim 0.5$. It is found that more than 4 kg of Am can be burned in one spallation target during the first year of operation.

Yury Malyshkin; Igor Pshenichnov; Igor Mishustin; Walter Greiner

2014-05-02T23:59:59.000Z

264

Lifting -- A Nonreversible Markov Chain Monte Carlo Algorithm  

E-Print Network [OSTI]

Markov Chain Monte Carlo algorithms are invaluable numerical tools for exploring stationary properties of physical systems -- in particular when direct sampling is not feasible. They are widely used in many areas of physics and other sciences. Most common implementations are done with reversible Markov chains -- Markov chains that obey detailed balance. Reversible Markov chains are sufficient in order for the physical system to relax to equilibrium, but it is not necessary. Here we review several works that use "lifted" or nonreversible Markov chains, which violate detailed balance, yet still converge to the correct stationary distribution (they obey the global balance condition). In certain cases, the acceleration is a square root improvement at most, to the conventional reversible Markov chains. We introduce the problem in a way that makes it accessible to non-specialists. We illustrate the method on several representative examples (sampling on a ring, sampling on a torus, an Ising model on a complete graph...

Vucelja, Marija

2015-01-01T23:59:59.000Z

265

Monte Carlo simulation study of scanning Auger electron images  

SciTech Connect (OSTI)

Simulation of contrast formation in Auger electron imaging of surfaces is helpful for analyzing scanning Auger microscopy/microanalysis (SAM) images. In this work, we have extended our previous Monte Carlo model and the simulation method for calculation of scanning electron microscopy (SEM) images to SAM images of complex structures. The essentials of the simulation method are as follows. (1) We use a constructive solid geometry modeling for a sample geometry, which is complex in elemental distribution, as well as in topographical configuration and a ray-tracing technique in the calculation procedure of electron flight steps that across the different element zones. The combination of the basic objects filled with elements, alloys, or compounds enables the simulation to a variety of sample geometries. (2) Sampled Auger signal electrons with a characteristic energy are generated in the simulation following an inner-shell ionization event, whose description is based on the Castani's inner-shell ionization cross section. This paper discusses in detail the features of simulated SAM images and of line scans for structured samples, i.e., the objects embedded in a matrix, under various experimental conditions (object size, location depth, beam energy, and the incident angle). Several effects are predicted and explained, such as the contrast reversion for nanoparticles in sizes of 10-60 nm, the contrast enhancement for particles made of different elements and wholly embedded in a matrix, and the artifact contrast due to nearby objects containing different elements. The simulated SAM images are also compared with the simulated SEM images of secondary electrons and of backscattered electrons. The results indicate that the Monte Carlo simulation can play an important role in quantitative SAM mapping.

Li, Y. G.; Ding, Z. J. [Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Z. M. [Department of Astronomy and Applied Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2009-07-15T23:59:59.000Z

266

MONTE-CARLO BURNUP CALCULATION UNCERTAINTY QUANTIFICATION AND PROPAGATION DETERMINATION  

SciTech Connect (OSTI)

MONTEBURNS is a Monte-Carlo depletion routine utilizing MCNP and ORIGEN 2.2. Uncertainties exist in the MCNP transport calculation, but this information is not passed to the depletion calculation in ORIGEN or saved. To quantify this transport uncertainty and determine how it propagates between burnup steps, a statistical analysis of a multiple repeated depletion runs is performed. The reactor model chosen is the Oak Ridge Research Reactor (ORR) in a single assembly, infinite lattice configuration. This model was burned for a 25.5 day cycle broken down into three steps. The output isotopics as well as effective multiplication factor (k-effective) were tabulated and histograms were created at each burnup step using the Scott Method to determine the bin width. It was expected that the gram quantities and k-effective histograms would produce normally distributed results since they were produced from a Monte-Carlo routine, but some of results do not. The standard deviation at each burnup step was consistent between fission product isotopes as expected, while the uranium isotopes created some unique results. The variation in the quantity of uranium was small enough that, from the reaction rate MCNP tally, round off error occurred producing a set of repeated results with slight variation. Statistical analyses were performed using the {chi}{sup 2} test against a normal distribution for several isotopes and the k-effective results. While the isotopes failed to reject the null hypothesis of being normally distributed, the {chi}{sup 2} statistic grew through the steps in the k-effective test. The null hypothesis was rejected in the later steps. These results suggest, for a high accuracy solution, MCNP cell material quantities less than 100 grams and greater kcode parameters are needed to minimize uncertainty propagation and minimize round off effects.

Nichols, T.; Sternat, M.; Charlton, W.

2011-05-08T23:59:59.000Z

267

Polarized light propagation in highly scattering turbid media with a distribution of the particle size: a Monte Carlo study  

E-Print Network [OSTI]

The light propagation in highly scattering turbid media composed of the particles with different size distribution is studied using a Monte Carlo simulation model implemented in Standard C. Monte Carlo method has been widely utilized to study...

Koh, Wonshill

2013-02-22T23:59:59.000Z

268

The evaluation of resistance of seedling alfalfa varieties and strains to the spotted alfalfa aphid, Therioaphis maculata (Buckton)  

E-Print Network [OSTI]

The Evaluation of Resistance oi Seedling Alfalfa Varieties and Strains to the Spotted Alfalfa Aphid, ~ggj, ~a~ Eggg~g (Buck- ton) EILFRED J. KLEi~KlT A Thesis Submitted to the Graduate School of the Agricultural aud Mechanical College of Texas... in partial 1'ulfillment of the requirements for the degree of MASTER UF SCIEECE January 1960 Major Subject: Entomology The Evaluation of Raeietance of SeecG. Lag Alfalfa Varietiee and ~trains to the Spotted Alfalfa Aphid& (3~ton) A Thesis By 4'iifred...

Klement, Wilfred John

1960-01-01T23:59:59.000Z

269

Impact of tool wear on joint strength in friction stir spot welding of DP 980 steel  

SciTech Connect (OSTI)

Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel (UHSS), both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Recently a new tool alloy has been developed, using a blend of PCBN and tungsten rhenium (W-Re) in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W-Re, and one with 70% PCBN and 30% W-Re. The sheet material used for all wear testing was 1.4 mm DP 980. Lap shear testing was used to show the relationship between tool wear and joint strength. The Q70 tool provided the best combination of wear resistance and joint strength.

Miles, Michael; Ridges, Chris; Hovanski, Yuri; Peterson, Jeremy; Santella, M. L.; Steel, Russel

2011-09-14T23:59:59.000Z

270

On the development of nugget growth model for resistance spot welding  

SciTech Connect (OSTI)

In this paper, we developed a general mathematical model to estimate the nugget growth process based on the heat energy delivered into the welds by the resistance spot welding. According to the principles of thermodynamics and heat transfer, and the effect of electrode force during the welding process, the shape of the nugget can be estimated. Then, a mathematical model between heat energy absorbed and nugget diameter can be obtained theoretically. It is shown in this paper that the nugget diameter can be precisely described by piecewise fractal polynomial functions. Experiments were conducted with different welding operation conditions, such as welding currents, workpiece thickness, and widths, to validate the model and the theoretical analysis. All the experiments confirmed that the proposed model can predict the nugget diameters with high accuracy based on the input heat energy to the welds.

Zhou, Kang, E-mail: zhoukang326@126.com, E-mail: melcai@ust.hk; Cai, Lilong, E-mail: zhoukang326@126.com, E-mail: melcai@ust.hk [Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2014-04-28T23:59:59.000Z

271

Empirical analysis of the spot market implications ofprice-elastic demand  

SciTech Connect (OSTI)

Regardless of the form of restructuring, deregulated electricity industries share one common feature: the absence of any significant, rapid demand-side response to the wholesale (or, spotmarket) price. For a variety of reasons, electricity industries continue to charge most consumers an average cost based on regulated retail tariff from the era of vertical integration, even as the retailers themselves are forced to purchase electricity at volatile wholesale prices set in open markets. This results in considerable price risk for retailers, who are sometimes forbidden by regulators from signing hedging contracts. More importantly, because end-users do not perceive real-time (or even hourly or daily) fluctuations in the wholesale price of electricity, they have no incentive to adjust their consumption in response to price signals. Consequently, demand for electricity is highly inelastic, and electricity generation resources can be stretched to the point where system stability is threatened. This, then, facilitates many other problems associated with electricity markets, such as market power and price volatility. Indeed, economic theory suggests that even modestly price-responsive demand can remove the stress on generation resources and decrease spot prices. To test this theory, we use actual generator bid data from the New York control area to construct supply stacks, and intersect them with demand curves of various slopes to approximate different levels of demand elasticity. We then estimate the potential impact of real-time pricing on the equilibrium spot price and quantity. These results indicate the immediate benefits that could be derived from a more price-elastic demand. Such analysis can provide policymakers with a measure of how effective price-elastic demand can potentially reduce prices and maintain consumption within the capability of generation resources.

Siddiqui, Afzal S.; Bartholomew, Emily S.; Marnay, Chris

2004-07-08T23:59:59.000Z

272

Empirical Analysis of the Spot Market Implications ofPrice-Responsive Demand  

SciTech Connect (OSTI)

Regardless of the form of restructuring, deregulatedelectricity industries share one common feature: the absence of anysignificant, rapid demand-side response to the wholesale (or, spotmarket) price. For a variety of reasons, most electricity consumers stillpay an average cost based regulated retail tariff held over from the eraof vertical integration, even as the retailers themselves are oftenforced to purchase electricity at volatile wholesale prices set in openmarkets. This results in considerable price risk for retailers, who aresometimes additionally forbidden by regulators from signing hedgingcontracts. More importantly, because end-users do not perceive real-time(or even hourly or daily) fluctuations in the wholesale price ofelectricity, they have no incentive to adjust their consumptionaccordingly. Consequently, demand for electricity is highly inelastic,which together with the non storability of electricity that requiresmarket clearing over very short time steps spawn many other problemsassociated with electricity markets, such as exercise of market power andprice volatility. Indeed, electricity generation resources can bestretched to the point where system adequacy is threatened. Economictheory suggests that even modest price responsiveness can relieve thestress on generation resources and decrease spot prices. To quantify thiseffect, actual generator bid data from the New York control area is usedto construct supply stacks and intersect them with demand curves ofvarious slopes to approximate the effect of different levels of demandresponse. The potential impact of real-time pricing (RTP) on theequilibrium spot price and quantity is then estimated. These resultsindicate the immediate benefits that could be derived from a moreprice-responsive demand providing policymakers with a measure of howprices can be potentially reduced and consumption maintained within thecapability of generation assets.

Siddiqui, Afzal S.; Bartholomew, Emily S.; Marnay, Chris

2005-08-01T23:59:59.000Z

273

Docket No. PA02-2-000 Price Manipulation in Western MarketsV-1 V. The Influence of Electricity Spot Prices on Electricity  

E-Print Network [OSTI]

of Electricity Spot Prices on Electricity Forward Prices Summary of Results The vital link between the spot price electric prices today and the forward price of electricity. Instead, forward prices should mostly reflect electricity in the West, forward gas prices should, in large part, explain forward electricity prices. Our

Laughlin, Robert B.

274

Quantum Monte Carlo Calculations Applied to Magnetic Molecules  

SciTech Connect (OSTI)

We have calculated the equilibrium thermodynamic properties of Heisenberg spin systems using a quantum Monte Carlo (QMC) method. We have used some of these systems as models to describe recently synthesized magnetic molecules, and-upon comparing the results of these calculations with experimental data-have obtained accurate estimates for the basic parameters of these models. We have also performed calculations for other systems that are of more general interest, being relevant both for existing experimental data and for future experiments. Utilizing the concept of importance sampling, these calculations can be carried out in an arbitrarily large quantum Hilbert space, while still avoiding any approximations that would introduce systematic errors. The only errors are statistical in nature, and as such, their magnitudes are accurately estimated during the course of a simulation. Frustrated spin systems present a major challenge to the QMC method, nevertheless, in many instances progress can be made. In this chapter, the field of magnetic molecules is introduced, paying particular attention to the characteristics that distinguish magnetic molecules from other systems that are studied in condensed matter physics. We briefly outline the typical path by which we learn about magnetic molecules, which requires a close relationship between experiments and theoretical calculations. The typical experiments are introduced here, while the theoretical methods are discussed in the next chapter. Each of these theoretical methods has a considerable limitation, also described in Chapter 2, which together serve to motivate the present work. As is shown throughout the later chapters, the present QMC method is often able to provide useful information where other methods fail. In Chapter 3, the use of Monte Carlo methods in statistical physics is reviewed, building up the fundamental ideas that are necessary in order to understand the method that has been used in this work. With these ideas in hand, we then provide a detailed explanation of the current QMC method in Chapter 4. The remainder of the thesis is devoted to presenting specific results: Chapters 5 and 6 contain articles in which this method has been used to answer general questions that are relevant to broad classes of systems. Then, in Chapter 7, we provide an analysis of four different species of magnetic molecules that have recently been synthesized and studied. In all cases, comparisons between QMC calculations and experimental data allow us to distinguish a viable microscopic model and make predictions for future experiments. In Chapter 8, the infamous ''negative sign problem'' is described in detail, and we clearly indicate the limitations on QMC that are imposed by this obstacle. Finally, Chapter 9 contains a summary of the present work and the expected directions for future research.

Larry Engelhardt

2006-08-09T23:59:59.000Z

275

Complete Monte Carlo Simulation of Neutron Scattering Experiments  

SciTech Connect (OSTI)

In the far past, it was not possible to accurately correct for the finite geometry and the finite sample size of a neutron scattering set-up. The limited calculation power of the ancient computers as well as the lack of powerful Monte Carlo codes and the limitation in the data base available then prevented a complete simulation of the actual experiment. Using e.g. the Monte Carlo neutron transport code MCNPX [1], neutron scattering experiments can be simulated almost completely with a high degree of precision using a modern PC, which has a computing power that is ten thousand times that of a super computer of the early 1970s. Thus, (better) corrections can also be obtained easily for previous published data provided that these experiments are sufficiently well documented. Better knowledge of reference data (e.g. atomic mass, relativistic correction, and monitor cross sections) further contributes to data improvement. Elastic neutron scattering experiments from liquid samples of the helium isotopes performed around 1970 at LANL happen to be very well documented. Considering that the cryogenic targets are expensive and complicated, it is certainly worthwhile to improve these data by correcting them using this comparatively straightforward method. As two thirds of all differential scattering cross section data of {sup 3}He(n,n){sup 3}He are connected to the LANL data, it became necessary to correct the dependent data measured in Karlsruhe, Germany, as well. A thorough simulation of both the LANL experiments and the Karlsruhe experiment is presented, starting from the neutron production, followed by the interaction in the air, the interaction with the cryostat structure, and finally the scattering medium itself. In addition, scattering from the hydrogen reference sample was simulated. For the LANL data, the multiple scattering corrections are smaller by a factor of five at least, making this work relevant. Even more important are the corrections to the Karlsruhe data due to the inclusion of the missing outgoing self-attenuation that amounts to up to 15%.

Drosg, M. [Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Wien (Austria)

2011-12-13T23:59:59.000Z

276

Strategic Behavior in Spot Markets for Electricity when Load is Stochastic Department of Agricultural, Resource, and Managerial Economics  

E-Print Network [OSTI]

Strategic Behavior in Spot Markets for Electricity when Load is Stochastic T.D. Mount Department of market power to raise prices above competitive levels in the UK market for electricity has been discussed in an electricity market. In spite of this abundant evidence, regulators in the USA have been relatively unconcerned

277

Assessing the Degree of Spot Market Integration For U.S. Natural Gas: Evidence from Daily Price Data  

E-Print Network [OSTI]

following the FERC's `open access' reforms of the late 1980s. Daily spot prices at 76 market locations from segmented from the more loosely integrated Western market. Thus, although the FERC reforms have contributed Commission (FERC) implemented a series of far-reaching regulatory reforms. These reforms were designed

278

P~!ETRIC STUDY OF HEAT FLOW DURING RESISTANCE SPOT WELDING Euiwhan Kim and Thomas W. Eagar  

E-Print Network [OSTI]

i ...) P~!ETRIC STUDY OF HEAT FLOW DURING RESISTANCE SPOT WELDING Euiwhan Kim and Thomas W. Eagar case of resistance welding to see the effects of each parameter on the lobe shape. The parameters include material proper- ties, geometry of electrodes and work piece, weld time and current

Eagar, Thomas W.

279

23. Gray{Scott equations Patterns are everywhere in nature. Examples include spots on butter ies, stripes on zebras, tri-  

E-Print Network [OSTI]

23. Gray{Scott equations Patterns are everywhere in nature. Examples include spots on butter ies variety. The Gray{Scott equations were formulated originally by Gray and Scott in 1983; we shall advantage of this principle. References P. Gray and S. K. Scott, papers in Chem. Eng. Sci. 38 (1983), 29

Trefethen, Nick

280

The sweet spot of forward osmosis: Treatment of produced water, drilling wastewater, and other complex and difficult liquid streams  

E-Print Network [OSTI]

, and especially oil and gas (O&G) exploration and production wastewaters. High salt concentrations, decentralized generated during exploration and production (E&P) (e.g., drilling muds, hydraulic fracturing flowback water processes, have identified its sweet spot: treatment and desalination of complex industrial streams

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Instabilities of a three-dimensional localized spot Marcin Leda, Vladimir K. Vanag, and Irving R. Epstein  

E-Print Network [OSTI]

-Zhabotinsky reaction in water-in-oil microemulsion. We find three types of instabili- ties: splitting of a single spot be classified as either supercritical or subcritical. In reaction-diffusion systems, supercritical instabilities of a ho- mogeneous steady state SS can give rise to small-amplitude patterns, while subcritical

Epstein, Irving R.

282

Monte Carlo simulations for generic granite repository studies  

SciTech Connect (OSTI)

In a collaborative study between Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) for the DOE-NE Office of Fuel Cycle Technologies Used Fuel Disposition (UFD) Campaign project, we have conducted preliminary system-level analyses to support the development of a long-term strategy for geologic disposal of high-level radioactive waste. A general modeling framework consisting of a near- and a far-field submodel for a granite GDSE was developed. A representative far-field transport model for a generic granite repository was merged with an integrated systems (GoldSim) near-field model. Integrated Monte Carlo model runs with the combined near- and farfield transport models were performed, and the parameter sensitivities were evaluated for the combined system. In addition, a sub-set of radionuclides that are potentially important to repository performance were identified and evaluated for a series of model runs. The analyses were conducted with different waste inventory scenarios. Analyses were also conducted for different repository radionuelide release scenarios. While the results to date are for a generic granite repository, the work establishes the method to be used in the future to provide guidance on the development of strategy for long-term disposal of high-level radioactive waste in a granite repository.

Chu, Shaoping [Los Alamos National Laboratory; Lee, Joon H [SNL; Wang, Yifeng [SNL

2010-12-08T23:59:59.000Z

283

An efficient approach to ab initio Monte Carlo simulation  

SciTech Connect (OSTI)

We present a Nested Markov chain Monte Carlo (NMC) scheme for building equilibrium averages based on accurate potentials such as density functional theory. Metropolis sampling of a reference system, defined by an inexpensive but approximate potential, was used to substantially decorrelate configurations at which the potential of interest was evaluated, thereby dramatically reducing the number needed to build ensemble averages at a given level of precision. The efficiency of this procedure was maximized on-the-fly through variation of the reference system thermodynamic state (characterized here by its inverse temperature ?{sup 0}), which was otherwise unconstrained. Local density approximation results are presented for shocked states of argon at pressures from 4 to 60 GPa, where—depending on the quality of the reference system potential—acceptance probabilities were enhanced by factors of 1.2–28 relative to unoptimized NMC. The optimization procedure compensated strongly for reference potential shortcomings, as evidenced by significantly higher speedups when using a reference potential of lower quality. The efficiency of optimized NMC is shown to be competitive with that of standard ab initio molecular dynamics in the canonical ensemble.

Leiding, Jeff; Coe, Joshua D., E-mail: jcoe@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2014-01-21T23:59:59.000Z

284

Hyperon Puzzle: Hints from Quantum Monte Carlo Calculations  

E-Print Network [OSTI]

The onset of hyperons in the core of neutron stars and the consequent softening of the equation of state have been questioned for a long time. Controversial theoretical predictions and recent astrophysical observations of neutron stars are the grounds for the so-called hyperon puzzle. We calculate the equation of state and the neutron star mass-radius relation of an infinite systems of neutrons and $\\Lambda$ particles by using the auxiliary field diffusion Monte Carlo algorithm. We find that the three-body hyperon-nucleon interaction plays a fundamental role in the softening of the equation of state and for the consequent reduction of the predicted maximum mass. We have considered two different models of three-body force that successfully describe the binding energy of medium mass hypernuclei. Our results indicate that they give dramatically different results on the maximum mass of neutron stars, not necessarily incompatible with the recent observation of very massive neutron stars. We conclude that stronger constraints on the hyperon-neutron force are necessary in order to properly assess the role of hyperons in neutron stars.

Diego Lonardoni; Alessandro Lovato; Stefano Gandolfi; Francesco Pederiva

2015-02-27T23:59:59.000Z

285

Global variance reduction for Monte Carlo reactor physics calculations  

SciTech Connect (OSTI)

Over the past few decades, hybrid Monte-Carlo-Deterministic (MC-DT) techniques have been mostly focusing on the development of techniques primarily with shielding applications in mind, i.e. problems featuring a limited number of responses. This paper focuses on the application of a new hybrid MC-DT technique: the SUBSPACE method, for reactor analysis calculation. The SUBSPACE method is designed to overcome the lack of efficiency that hampers the application of MC methods in routine analysis calculations on the assembly level where typically one needs to execute the flux solver in the order of 10{sup 3}-10{sup 5} times. It places high premium on attaining high computational efficiency for reactor analysis application by identifying and capitalizing on the existing correlations between responses of interest. This paper places particular emphasis on using the SUBSPACE method for preparing homogenized few-group cross section sets on the assembly level for subsequent use in full-core diffusion calculations. A BWR assembly model is employed to calculate homogenized few-group cross sections for different burn-up steps. It is found that using the SUBSPACE method significant speedup can be achieved over the state of the art FW-CADIS method. While the presented speed-up alone is not sufficient to render the MC method competitive with the DT method, we believe this work will become a major step on the way of leveraging the accuracy of MC calculations for assembly calculations. (authors)

Zhang, Q.; Abdel-Khalik, H. S. [Department of Nuclear Engineering, North Carolina State University, P.O. Box 7909, Raleigh, NC 27695-7909 (United States)

2013-07-01T23:59:59.000Z

286

Ensemble bayesian model averaging using markov chain Monte Carlo sampling  

SciTech Connect (OSTI)

Bayesian model averaging (BMA) has recently been proposed as a statistical method to calibrate forecast ensembles from numerical weather models. Successful implementation of BMA however, requires accurate estimates of the weights and variances of the individual competing models in the ensemble. In their seminal paper (Raftery etal. Mon Weather Rev 133: 1155-1174, 2(05)) has recommended the Expectation-Maximization (EM) algorithm for BMA model training, even though global convergence of this algorithm cannot be guaranteed. In this paper, we compare the performance of the EM algorithm and the recently developed Differential Evolution Adaptive Metropolis (DREAM) Markov Chain Monte Carlo (MCMC) algorithm for estimating the BMA weights and variances. Simulation experiments using 48-hour ensemble data of surface temperature and multi-model stream-flow forecasts show that both methods produce similar results, and that their performance is unaffected by the length of the training data set. However, MCMC simulation with DREAM is capable of efficiently handling a wide variety of BMA predictive distributions, and provides useful information about the uncertainty associated with the estimated BMA weights and variances.

Vrugt, Jasper A [Los Alamos National Laboratory; Diks, Cees G H [NON LANL; Clark, Martyn P [NON LANL

2008-01-01T23:59:59.000Z

287

Monte Carlo Simulations of Microchannel Plate Based, Fast-Gated X-Ray Imagers  

SciTech Connect (OSTI)

This is a chapter in a book titled Applications of Monte Carlo Method in Science and Engineering Edited by: Shaul Mordechai ISBN 978-953-307-691-1, Hard cover, 950 pages Publisher: InTech Publication date: February 2011

Wu., M., Kruschwitz, C.

2011-02-01T23:59:59.000Z

288

Fermion-dimer scattering using an impurity lattice Monte Carlo approach and the adiabatic projection method  

E-Print Network [OSTI]

We present lattice Monte Carlo calculations of fermion-dimer scattering in the limit of zero-range interactions using the adiabatic projection method. The adiabatic projection method uses a set of initial cluster states and Euclidean time projection to give a systematically improvable description of the low-lying scattering cluster states in a finite volume. We use L\\"uscher's finite-volume relations to determine the s-wave, p-wave, and d-wave phase shifts. For comparison, we also compute exact lattice results using Lanczos iteration and continuum results using the Skorniakov-Ter-Martirosian equation. For our Monte Carlo calculations we use a new lattice algorithm called impurity lattice Monte Carlo. This algorithm can be viewed as a hybrid technique which incorporates elements of both worldline and auxiliary-field Monte Carlo simulations.

Serdar Elhatisari; Dean Lee

2014-12-01T23:59:59.000Z

289

E-Print Network 3.0 - atlas monte carlo Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

carlo Search Powered by Explorit Topic List Advanced Search Sample search results for: atlas monte carlo Page: << < 1 2 3 4 5 > >> 1 NSF UChicago: Tier 2 and Tier 3 1 Tier 2 and...

290

Nuclear Structure and Reactions (Quantum Monte Carlo, Lanczos Methods, Density Functional Methods), June 6 10  

E-Print Network [OSTI]

Nuclear Structure and Reactions (Quantum Monte Carlo, Lanczos Methods, Density Functional Methods systems: nuclei and the unitary Fermi gas" Thursday, June 9 10:00 am Stefano Gandolfi "Ab

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

291

Particle-In-Cell/Monte Carlo Simulation of Ion Back Bombardment in Photoinjectors  

E-Print Network [OSTI]

on the photocathode in rf guns are order of magnitude lowerthan that in a dc gun. A higher rf frequency helpsof the cathode in rf guns. Keywords: particle-in-cell/Monte

Qiang, Ji

2009-01-01T23:59:59.000Z

292

Protein folding and phylogenetic tree reconstruction using stochastic approximation Monte Carlo  

E-Print Network [OSTI]

folding problems. The numerical results indicate that it outperforms simulated annealing and conventional Monte Carlo algorithms as a stochastic optimization algorithm. We also propose one method for the use of secondary structures in protein folding...

Cheon, Sooyoung

2007-09-17T23:59:59.000Z

293

ATLAS Monte Carlo production Run-1 experience and readiness for Run-2 challenges  

E-Print Network [OSTI]

In this presentation we will review the ATLAS Monte Carlo production setup including the different production steps involved in full and fast detector simulation. A report on the Monte Carlo production campaigns during Run-I, Long Shutdown 1 (LS1) and status of the production for Run-2 will be presented. The presentation will include the details on various performance aspects. Important improvements in the workflow and software will be highlighted. Besides standard Monte Carlo production for data analyses at 7 and 8 TeV, the production accommodates for various specialised activities. These range from extended Monte Carlo validation, Geant4 validation, pileup simulation using zero bias data and production for various upgrade studies. The challenges of these activities will be discussed.

Chapman, John Derek; The ATLAS collaboration; Garcia Navarro, Jose Enrique; Gwenlan, Claire; Mehlhase, Sascha; Tsulaia, Vakhtang; Vaniachine, Alexandre; Zhong, Jiahang; Pacheco Pages, Andres

2015-01-01T23:59:59.000Z

294

Efficient scene simulation for robust monte carlo localization using an RGB-D camera  

E-Print Network [OSTI]

This paper presents Kinect Monte Carlo Localization (KMCL), a new method for localization in three dimensional indoor environments using RGB-D cameras, such as the Microsoft Kinect. The approach makes use of a low fidelity ...

Fallon, Maurice Francis

2013-05-14T23:59:59.000Z

295

Annealing contour Monte Carlo algorithm for structure optimization in an off-lattice protein model  

E-Print Network [OSTI]

. For example, the HP model1 treats each amino acid as a point particle and restricts the model to fold of the energy landscape, so it is an excellent tool for Monte Carlo optimization. The ACMC algorithm is an accel

Liang, Faming

296

Monte Carlo simulation model for electromagnetic scattering from vegetation and inversion of vegetation parameters  

E-Print Network [OSTI]

In this thesis research, a coherent scattering model for microwave remote sensing of vegetation canopy is developed on the basis of Monte Carlo simulations. An accurate model of vegetation structure is essential for the ...

Wang, Li-Fang, Ph. D. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

297

Comparison of value-added models for school ranking and classification: a Monte Carlo study  

E-Print Network [OSTI]

COMPARISON OF VALUE-ADDED MODELS FOR SCHOOL RANKING AND CLASSIFICATION: A MONTE CARLO STUDY A Dissertation by ZHONGMIAO WANG Submitted to the Office of Graduate Studies of Texas A&M University... AND CLASSIFICATION: A MONTE CARLO STUDY A Dissertation by ZHONGMIAO WANG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Co...

Wang, Zhongmiao

2009-05-15T23:59:59.000Z

298

Novel Hybrid Monte Carlo/Deterministic Technique for Shutdown Dose Rate Analyses of Fusion Energy Systems  

SciTech Connect (OSTI)

The rigorous 2-step (R2S) method uses three-dimensional Monte Carlo transport simulations to calculate the shutdown dose rate (SDDR) in fusion reactors. Accurate full-scale R2S calculations are impractical in fusion reactors because they require calculating space- and energy-dependent neutron fluxes everywhere inside the reactor. The use of global Monte Carlo variance reduction techniques was suggested for accelerating the neutron transport calculation of the R2S method. The prohibitive computational costs of these approaches, which increase with the problem size and amount of shielding materials, inhibit their use in the accurate full-scale neutronics analyses of fusion reactors. This paper describes a novel hybrid Monte Carlo/deterministic technique that uses the Consistent Adjoint Driven Importance Sampling (CADIS) methodology but focuses on multi-step shielding calculations. The Multi-Step CADIS (MS-CADIS) method speeds up the Monte Carlo neutron calculation of the R2S method using an importance function that represents the importance of the neutrons to the final SDDR. Using a simplified example, preliminarily results showed that the use of MS-CADIS enhanced the efficiency of the neutron Monte Carlo simulation of an SDDR calculation by a factor of 550 compared to standard global variance reduction techniques, and that the increase over analog Monte Carlo is higher than 10,000.

Ibrahim, Ahmad M [ORNL] [ORNL; Peplow, Douglas E. [ORNL] [ORNL; Peterson, Joshua L [ORNL] [ORNL; Grove, Robert E [ORNL] [ORNL

2013-01-01T23:59:59.000Z

299

Aspects of the life history and population dynamics of the spot, Leiostomus xanthurus, in the Northwestern Gulf of Mexico  

E-Print Network [OSTI]

. Spot are distributed from &5 to 73 m but are most abundant at 5-9 m. Spot of one cohort recruit to the Gulf primarily in two periods, May- July (Spring), at 3-7 mo, and January-March (winter), at 13-18 mo of age. Recruitment occurs in waters &5-16 m.... Collection Observed Size Ran e 955 Confidence Limits about h N 99% Conf idence Limits of bs rvations Spring Recruitment Group 1 Oct 77 D 4 Rov 77 D 137-207 166, 1 148-201 173. 1 69 331. 2 9 373. 6 161. 7-170. 5 158. 2-188. 0 117. 7-214. 5...

Hata, David Noboru

1985-01-01T23:59:59.000Z

300

Analysis of testing the single-fluxon dynamics in a long Josephson junction by a dissipative spot  

SciTech Connect (OSTI)

A change of the [ital I]-[ital V] characteristics of a long Josephson junction, operating in the zero-field single-fluxon regime, under the action of a hot spot'' (e.g., created by a focused electron beam) is calculated analytically by means of the perturbation theory, and also investigated numerically. The change of the average voltage at a given value of the bias current is calculated as a function of the hot spot-position. The overlap Josephson junction geometry is considered in detail, while the inline one is briefly discussed. A good accord between analytical and numerical results is found. The results are relevant for the interpretation of the low-temperature scanning electron microscopy experiments on imaging the fluxon dynamic states in a long Josephson junction.

Malomed, B.A. (Dipartimento di Fisica, Universita di Salerno, I-84801 Baronissi (Saudi Arabia) (Italy)); Ustinov, A.V. (Institute for Thin Films and Ion Technology, Research Centre (KFA), D-52425 Juelich (Germany))

1994-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Monte Carlo Simulations of the Corrosion of Aluminoborosilicate Glasses  

SciTech Connect (OSTI)

Aluminum is one of the most common components included in nuclear waste glasses. Therefore, Monte Carlo (MC) simulations were carried out to investigate the influence of aluminum on the rate and mechanism of dissolution of sodium borosilicate glasses in static conditions. The glasses studied were in the compositional range (70-2x)% SiO2 x% Al2O3 15% B2O3 (15+x)% Na2O, where 0 ? x ? 15%. The simulation results show that increasing amounts of aluminum in the pristine glasses slow down the initial rate of dissolution as determined from the rate of boron release. However, the extent of corrosion - as measured by the total amount of boron release - initially increases with addition of Al2O3, up to 5 Al2O3 mol%, but subsequently decreases with further Al2O3 addition. The MC simulations reveal that this behavior is due to the interplay between two opposing mechanisms: (1) aluminum slows down the kinetics of hydrolysis/condensation reactions that drive the reorganization of the glass surface and eventual formation of a blocking layer; and (2) aluminum strengthens the glass thereby increasing the lifetime of the upper part of its surface and allowing for more rapid formation of a blocking layer. Additional MC simulations were performed whereby a process representing the formation of a secondary aluminosilicate phase was included. Secondary phase formation draws dissolved glass components out of the aqueous solution, thereby diminishing the rate of condensation and delaying the formation of a blocking layer. As a result, the extent of corrosion is found to increase continuously with increasing Al2O3 content, as observed experimentally. For Al2O3 < 10 mol%, the MC simulations also indicate that, because the secondary phase solubility eventually controls the aluminum content in the part of the altered layer in contact with the bulk aqueous solution, the dissolved aluminum and silicon concentrations at steady state are not dependent on the Al2O3 content of the pristine aluminoborosilicate glass.

Kerisit, Sebastien N.; Ryan, Joseph V.; Pierce, Eric M.

2013-10-15T23:59:59.000Z

302

Monte Carlo Simulations of the Corrosion of Aluminoborosilicate Glasses  

SciTech Connect (OSTI)

Aluminum is one of the most common components included in nuclear waste glasses. Therefore, Monte Carlo (MC) simulations were carried out to investigate the influence of aluminum on the rate and mechanism of dissolution of sodium borosilicate glasses in static conditions. The glasses studied were in the compositional range (70 2x)% SiO2x% Al2O3 15% B2O3 (15 + x)% Na2O, where 0 x 15%. The simulation results show that increasing amounts of aluminum in the pristine glasses slow down the initial rate of dissolution as determined from the rate of boron release. However, the extent of corrosion as measured by the total amount of boron release initially increases with addition of Al2O3, up to 5 mol% Al2O3, but subsequently decreases with further Al2O3 addition. The MC simulations reveal that this behavior is due to the interplay between two opposing mechanisms: (1) aluminum slows down the kinetics of hydrolysis/condensation reactions that drive the reorganization of the glass surface and eventual formation of a blocking layer; and (2) aluminum strengthens the glass thereby increasing the lifetime of the upper part of its surface and allowing for more rapid formation of a blocking layer. Additional MC simulations were performed whereby a process representing the formation of a secondary aluminosilicate phase was included. Secondary phase formation draws dissolved glass components out of the aqueous solution, thereby diminishing the rate of condensation and delaying the formation of a blocking layer. As a result, the extent of corrosion is found to increase continuously with increasing Al2O3 content, as observed experimentally. For Al2O3 < 10 mol%, the MC simulations also indicate that, because the secondary phase solubility eventually controls the aluminum content in the part of the altered layer in contact with the bulk aqueous solution, the dissolved aluminum and silicon concentrations at steady state are not dependent on the Al2O3 content of the pristine aluminoborosilicate glass.

Kerisit, Sebastien [Pacific Northwest National Laboratory (PNNL); Ryan, Joseph V [Pacific Northwest National Laboratory (PNNL); Pierce, Eric M [ORNL

2013-01-01T23:59:59.000Z

303

Detection of surface carbon and hydrocarbons in hot spot regions of niobium superconducting rf cavities by Raman spectroscopy  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

Raman microscopy/spectroscopy measurements are presented on high purity niobium (Nb) samples, including pieces from hot spot regions of a tested superconducting rf cavity that exhibit a high density of etch pits. Measured spectra are compared with density functional theory calculations of Raman-active, vibrational modes of possible surface Nb-O and Nb-H complexes. The Raman spectra inside particularly rough pits in all Nb samples show clear differences from surrounding areas, exhibiting enhanced intensity and sharp peaks. While some of the sharp peaks are consistent with calculated NbH and NbH2 modes, there is better overall agreement with C-H modes in chain-type hydrocarbons. Other spectra reveal two broader peaks attributed to amorphous carbon. Niobium foils annealed to >2000°C in high vacuum develop identical Raman peaks when subjected to cold working. Regions with enhanced C and O have also been found by SEM/EDX spectroscopy in the hot spot samples and cold-worked foils, corroborating the Raman results. Such regions with high concentrations of impurities are expected to suppress the local superconductivity and this may explain the correlation between hot spots in superconducting rf (SRF) cavities and the observation of a high density of surface pits. The origin of localized high carbon and hydrocarbon regions is unclear at present but it is suggested that particular processing steps in SRF cavity fabrication may be responsible.

Cao, C.; Ford, D.; Bishnoi, S.; Proslier, T.; Albee, B.; Hommerding, E.; Korczakowski, A.; Cooley, L.; Ciovati, G.; Zasadzinski, J. F.

2013-06-01T23:59:59.000Z

304

Mthodes de Monte Carlo et processus stochastiques Pierre Del Moral -Stefano De Marco -Massimiliano Gubinelli -Benjamin Jourdain  

E-Print Network [OSTI]

Méthodes de Monte Carlo et processus stochastiques Pierre Del Moral - Stefano De Marco Monte Carlo et processus stochastiques: du linéaire au non linéaire (E. Gobet). On considère un système Méthodes de Monte Carlo et processus stochastiques: du linéaire au non linéaire (E. Gobet). On considère

Del Moral , Pierre

305

Mthodes de Monte Carlo et processus stochastiques Pierre Del Moral -Stefano De Marco -Massimiliano Gubinelli -Benjamin Jourdain  

E-Print Network [OSTI]

Méthodes de Monte Carlo et processus stochastiques Pierre Del Moral - Stefano De Marco de refaire l'une des expériences de simulation de Monte Carlo les plus anciennes, proposée en 1733 aiguille touche le bord d'une latte. 1. Méthode de Monte Carlo : Vérifier numériquement que la probabilité

Del Moral , Pierre

306

Fission matrix-based Monte Carlo criticality analysis of fuel storage pools  

SciTech Connect (OSTI)

Standard Monte Carlo transport procedures experience difficulties in solving criticality problems in fuel storage pools. Because of the strong neutron absorption between fuel assemblies, source convergence can be very slow, leading to incorrect estimates of the eigenvalue and the eigenfunction. This study examines an alternative fission matrix-based Monte Carlo transport method that takes advantage of the geometry of a storage pool to overcome this difficulty. The method uses Monte Carlo transport to build (essentially) a fission matrix, which is then used to calculate the criticality and the critical flux. This method was tested using a test code on a simple problem containing 8 assemblies in a square pool. The standard Monte Carlo method gave the expected eigenfunction in 5 cases out of 10, while the fission matrix method gave the expected eigenfunction in all 10 cases. In addition, the fission matrix method provides an estimate of the error in the eigenvalue and the eigenfunction, and it allows the user to control this error by running an adequate number of cycles. Because of these advantages, the fission matrix method yields a higher confidence in the results than standard Monte Carlo. We also discuss potential improvements of the method, including the potential for variance reduction techniques. (authors)

Farlotti, M. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Ecole Polytechnique, Palaiseau, F 91128 (France); Larsen, E. W. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States)

2013-07-01T23:59:59.000Z

307

Calculation of radiation therapy dose using all particle Monte Carlo transport  

DOE Patents [OSTI]

The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media.

Chandler, William P. (Tracy, CA); Hartmann-Siantar, Christine L. (San Ramon, CA); Rathkopf, James A. (Livermore, CA)

1999-01-01T23:59:59.000Z

308

Calculation of radiation therapy dose using all particle Monte Carlo transport  

DOE Patents [OSTI]

The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media. 57 figs.

Chandler, W.P.; Hartmann-Siantar, C.L.; Rathkopf, J.A.

1999-02-09T23:59:59.000Z

309

Crossing the mesoscale no-mans land via parallel kinetic Monte Carlo.  

SciTech Connect (OSTI)

The kinetic Monte Carlo method and its variants are powerful tools for modeling materials at the mesoscale, meaning at length and time scales in between the atomic and continuum. We have completed a 3 year LDRD project with the goal of developing a parallel kinetic Monte Carlo capability and applying it to materials modeling problems of interest to Sandia. In this report we give an overview of the methods and algorithms developed, and describe our new open-source code called SPPARKS, for Stochastic Parallel PARticle Kinetic Simulator. We also highlight the development of several Monte Carlo models in SPPARKS for specific materials modeling applications, including grain growth, bubble formation, diffusion in nanoporous materials, defect formation in erbium hydrides, and surface growth and evolution.

Garcia Cardona, Cristina (San Diego State University); Webb, Edmund Blackburn, III; Wagner, Gregory John; Tikare, Veena; Holm, Elizabeth Ann; Plimpton, Steven James; Thompson, Aidan Patrick; Slepoy, Alexander (U. S. Department of Energy, NNSA); Zhou, Xiao Wang; Battaile, Corbett Chandler; Chandross, Michael Evan

2009-10-01T23:59:59.000Z

310

General purpose dynamic Monte Carlo with continuous energy for transient analysis  

SciTech Connect (OSTI)

For safety assessments transient analysis is an important tool. It can predict maximum temperatures during regular reactor operation or during an accident scenario. Despite the fact that this kind of analysis is very important, the state of the art still uses rather crude methods, like diffusion theory and point-kinetics. For reference calculations it is preferable to use the Monte Carlo method. In this paper the dynamic Monte Carlo method is implemented in the general purpose Monte Carlo code Tripoli4. Also, the method is extended for use with continuous energy. The first results of Dynamic Tripoli demonstrate that this kind of calculation is indeed accurate and the results are achieved in a reasonable amount of time. With the method implemented in Tripoli it is now possible to do an exact transient calculation in arbitrary geometry. (authors)

Sjenitzer, B. L.; Hoogenboom, J. E. [Delft Univ. of Technology, Dept. of Radiation, Radionuclide and Reactors, Mekelweg 15, 2629JB Delft (Netherlands)

2012-07-01T23:59:59.000Z

311

Revised methods for few-group cross sections generation in the Serpent Monte Carlo code  

SciTech Connect (OSTI)

This paper presents new calculation methods, recently implemented in the Serpent Monte Carlo code, and related to the production of homogenized few-group constants for deterministic 3D core analysis. The new methods fall under three topics: 1) Improved treatment of neutron-multiplying scattering reactions, 2) Group constant generation in reflectors and other non-fissile regions and 3) Homogenization in leakage-corrected criticality spectrum. The methodology is demonstrated by a numerical example, comparing a deterministic nodal diffusion calculation using Serpent-generated cross sections to a reference full-core Monte Carlo simulation. It is concluded that the new methodology improves the results of the deterministic calculation, and paves the way for Monte Carlo based group constant generation. (authors)

Fridman, E. [Reactor Safety Div., Helmholz-Zentrum Dresden-Rossendorf, POB 51 01 19, Dresden, 01314 (Germany); Leppaenen, J. [VTT Technical Research Centre of Finland, POB 1000, FI-02044 VTT (Finland)

2012-07-01T23:59:59.000Z

312

Full 3D visualization tool-kit for Monte Carlo and deterministic transport codes  

SciTech Connect (OSTI)

We propose a package of tools capable of translating the geometric inputs and outputs of many Monte Carlo and deterministic radiation transport codes into open source file formats. These tools are aimed at bridging the gap between trusted, widely-used radiation analysis codes and very powerful, more recent and commonly used visualization software, thus supporting the design process and helping with shielding optimization. Three main lines of development were followed: mesh-based analysis of Monte Carlo codes, mesh-based analysis of deterministic codes and Monte Carlo surface meshing. The developed kit is considered a powerful and cost-effective tool in the computer-aided design for radiation transport code users of the nuclear world, and in particular in the fields of core design and radiation analysis. (authors)

Frambati, S.; Frignani, M. [Ansaldo Nucleare S.p.A., Corso F.M. Perrone 25, 1616 Genova (Italy)

2012-07-01T23:59:59.000Z

313

A Proposal for a Standard Interface Between Monte Carlo Tools And One-Loop Programs  

SciTech Connect (OSTI)

Many highly developed Monte Carlo tools for the evaluation of cross sections based on tree matrix elements exist and are used by experimental collaborations in high energy physics. As the evaluation of one-loop matrix elements has recently been undergoing enormous progress, the combination of one-loop matrix elements with existing Monte Carlo tools is on the horizon. This would lead to phenomenological predictions at the next-to-leading order level. This note summarises the discussion of the next-to-leading order multi-leg (NLM) working group on this issue which has been taking place during the workshop on Physics at TeV Colliders at Les Houches, France, in June 2009. The result is a proposal for a standard interface between Monte Carlo tools and one-loop matrix element programs.

Binoth, T.; /Edinburgh U.; Boudjema, F.; /Annecy, LAPP; Dissertori, G.; Lazopoulos, A.; /Zurich, ETH; Denner, A.; /PSI, Villigen; Dittmaier, S.; /Freiburg U.; Frederix, R.; Greiner, N.; Hoeche, Stefan; /Zurich U.; Giele, W.; Skands, P.; Winter, J.; /Fermilab; Gleisberg, T.; /SLAC; Archibald, J.; Heinrich, G.; Krauss, F.; Maitre, D.; /Durham U., IPPP; Huber, M.; /Munich, Max Planck Inst.; Huston, J.; /Michigan State U.; Kauer, N.; /Royal Holloway, U. of London; Maltoni, F.; /Louvain U., CP3 /Milan Bicocca U. /INFN, Turin /Turin U. /Granada U., Theor. Phys. Astrophys. /CERN /NIKHEF, Amsterdam /Heidelberg U. /Oxford U., Theor. Phys.

2011-11-11T23:59:59.000Z

314

A proposal for a standard interface between Monte Carlo tools and one-loop programs  

SciTech Connect (OSTI)

Many highly developed Monte Carlo tools for the evaluation of cross sections based on tree matrix elements exist and are used by experimental collaborations in high energy physics. As the evaluation of one-loop matrix elements has recently been undergoing enormous progress, the combination of one-loop matrix elements with existing Monte Carlo tools is on the horizon. This would lead to phenomenological predictions at the next-to-leading order level. This note summarizes the discussion of the next-to-leading order multi-leg (NLM) working group on this issue which has been taking place during the workshop on Physics at TeV colliders at Les Houches, France, in June 2009. The result is a proposal for a standard interface between Monte Carlo tools and one-loop matrix element programs.

Binoth, T.; Boudjema, F.; Dissertori, G.; Lazopoulos, A.; Denner, A.; Dittmaier, S.; Frederix, R.; Greiner, N.; Hoche, S.; Giele, W.; Skands, P.

2010-01-01T23:59:59.000Z

315

Monte Carlo calculation of helical tomotherapy dose delivery  

SciTech Connect (OSTI)

Helical tomotherapy delivers intensity modulated radiation therapy using a binary multileaf collimator (MLC) to modulate a fan beam of radiation. This delivery occurs while the linac gantry and treatment couch are both in constant motion, so the beam describes, from a patient/phantom perspective, a spiral or helix of dose. The planning system models this continuous delivery as a large number (51) of discrete gantry positions per rotation, and given the small jaw/fan width setting typically used (1 or 2.5 cm) and the number of overlapping rotations used to cover the target (pitch often <0.5), the treatment planning system (TPS) potentially employs a very large number of static beam directions and leaf opening configurations to model the modulated fields. All dose calculations performed by the system employ a convolution/superposition model. In this work the authors perform a full Monte Carlo (MC) dose calculation of tomotherapy deliveries to phantom computed tomography (CT) data sets to verify the TPS calculations. All MC calculations are performed with the EGSnrc-based MC simulation codes, BEAMnrc and DOSXYZnrc. Simulations are performed by taking the sinogram (leaf opening versus time) of the treatment plan and decomposing it into 51 different projections per rotation, as does the TPS, each of which is segmented further into multiple MLC opening configurations, each with different weights that correspond to leaf opening times. Then the projection is simulated by the summing of all of the opening configurations, and the overall rotational treatment is simulated by the summing of all of the projection simulations. Commissioning of the source model was verified by comparing measured and simulated values for the percent depth dose and beam profiles shapes for various jaw settings. The accuracy of the MLC leaf width and tongue and groove spacing were verified by comparing measured and simulated values for the MLC leakage and a picket fence pattern. The validated source and MLC configuration were then used to simulate a complex modulated delivery from fixed gantry angle. Further, a preliminary rotational treatment plan to a delivery quality assurance phantom (the 'cheese' phantom) CT data set was simulated. Simulations were compared with measured results taken with an A1SL ionization chamber or EDR2 film measurements in a water tank or in a solid water phantom, respectively. The source and MLC MC simulations agree with the film measurements, with an acceptable number of pixels passing the 2%/1 mm gamma criterion. 99.8% of voxels of the MC calculation in the planning target volume (PTV) of the preliminary plan passed the 2%/2 mm gamma value test. 87.0% and 66.2% of the voxels in two organs at risk (OARs) passed the 2%/2 mm tests. For a 3%/3 mm criterion, the PTV and OARs show 100%, 93.2%, and 86.6% agreement, respectively. All voxels passed the gamma value test with a criterion of 5%/3 mm. The TomoTherapy TPS showed comparable results.

Zhao Yingli; Mackenzie, M.; Kirkby, C.; Fallone, B. G. [Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada and Department of Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

2008-08-15T23:59:59.000Z

316

Advanced Mesh-Enabled Monte carlo capability for Multi-Physics Reactor Analysis  

SciTech Connect (OSTI)

This project will accumulate high-precision fluxes throughout reactor geometry on a non- orthogonal grid of cells to support multi-physics coupling, in order to more accurately calculate parameters such as reactivity coefficients and to generate multi-group cross sections. This work will be based upon recent developments to incorporate advanced geometry and mesh capability in a modular Monte Carlo toolkit with computational science technology that is in use in related reactor simulation software development. Coupling this capability with production-scale Monte Carlo radiation transport codes can provide advanced and extensible test-beds for these developments. Continuous energy Monte Carlo methods are generally considered to be the most accurate computational tool for simulating radiation transport in complex geometries, particularly neutron transport in reactors. Nevertheless, there are several limitations for their use in reactor analysis. Most significantly, there is a trade-off between the fidelity of results in phase space, statistical accuracy, and the amount of computer time required for simulation. Consequently, to achieve an acceptable level of statistical convergence in high-fidelity results required for modern coupled multi-physics analysis, the required computer time makes Monte Carlo methods prohibitive for design iterations and detailed whole-core analysis. More subtly, the statistical uncertainty is typically not uniform throughout the domain, and the simulation quality is limited by the regions with the largest statistical uncertainty. In addition, the formulation of neutron scattering laws in continuous energy Monte Carlo methods makes it difficult to calculate adjoint neutron fluxes required to properly determine important reactivity parameters. Finally, most Monte Carlo codes available for reactor analysis have relied on orthogonal hexahedral grids for tallies that do not conform to the geometric boundaries and are thus generally not well-suited to coupling with the unstructured meshes that are used in other physics simulations.

Wilson, Paul; Evans, Thomas; Tautges, Tim

2012-12-24T23:59:59.000Z

317

A Monte Carlo synthetic-acceleration method for solving the thermal radiation diffusion equation  

SciTech Connect (OSTI)

We present a novel synthetic-acceleration-based Monte Carlo method for solving the equilibrium thermal radiation diffusion equation in three spatial dimensions. The algorithm performance is compared against traditional solution techniques using a Marshak benchmark problem and a more complex multiple material problem. Our results show that our Monte Carlo method is an effective solver for sparse matrix systems. For solutions converged to the same tolerance, it performs competitively with deterministic methods including preconditioned conjugate gradient and GMRES. We also discuss various aspects of preconditioning the method and its general applicability to broader classes of problems.

Evans, Thomas M., E-mail: evanstm@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37831 (United States); Mosher, Scott W., E-mail: moshersw@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37831 (United States); Slattery, Stuart R., E-mail: sslattery@wisc.edu [University of Wisconsin–Madison, 1500 Engineering Dr., Madison, WI 53716 (United States); Hamilton, Steven P., E-mail: hamiltonsp@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37831 (United States)

2014-02-01T23:59:59.000Z

318

A Monte Carlo Synthetic-Acceleration Method for Solving the Thermal Radiation Diffusion Equation  

SciTech Connect (OSTI)

We present a novel synthetic-acceleration based Monte Carlo method for solving the equilibrium thermal radiation diusion equation in three dimensions. The algorithm performance is compared against traditional solution techniques using a Marshak benchmark problem and a more complex multiple material problem. Our results show that not only can our Monte Carlo method be an eective solver for sparse matrix systems, but also that it performs competitively with deterministic methods including preconditioned Conjugate Gradient while producing numerically identical results. We also discuss various aspects of preconditioning the method and its general applicability to broader classes of problems.

Evans, Thomas M [ORNL] [ORNL; Mosher, Scott W [ORNL] [ORNL; Slattery, Stuart [University of Wisconsin, Madison] [University of Wisconsin, Madison

2014-01-01T23:59:59.000Z

319

Pseudo-random number generators for Monte Carlo simulations on Graphics Processing Units  

E-Print Network [OSTI]

Basic uniform pseudo-random number generators are implemented on ATI Graphics Processing Units (GPU). The performance results of the realized generators (multiplicative linear congruential (GGL), XOR-shift (XOR128), RANECU, RANMAR, RANLUX and Mersenne Twister (MT19937)) on CPU and GPU are discussed. The obtained speed-up factor is hundreds of times in comparison with CPU. RANLUX generator is found to be the most appropriate for using on GPU in Monte Carlo simulations. The brief review of the pseudo-random number generators used in modern software packages for Monte Carlo simulations in high-energy physics is present.

Demchik, Vadim

2010-01-01T23:59:59.000Z

320

Pseudo-random number generators for Monte Carlo simulations on Graphics Processing Units  

E-Print Network [OSTI]

Basic uniform pseudo-random number generators are implemented on ATI Graphics Processing Units (GPU). The performance results of the realized generators (multiplicative linear congruential (GGL), XOR-shift (XOR128), RANECU, RANMAR, RANLUX and Mersenne Twister (MT19937)) on CPU and GPU are discussed. The obtained speed-up factor is hundreds of times in comparison with CPU. RANLUX generator is found to be the most appropriate for using on GPU in Monte Carlo simulations. The brief review of the pseudo-random number generators used in modern software packages for Monte Carlo simulations in high-energy physics is present.

Vadim Demchik

2010-03-09T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Milagro Version 2 An Implicit Monte Carlo Code for Thermal Radiative Transfer: Capabilities, Development, and Usage  

SciTech Connect (OSTI)

We have released Version 2 of Milagro, an object-oriented, C++ code that performs radiative transfer using Fleck and Cummings' Implicit Monte Carlo method. Milagro, a part of the Jayenne program, is a stand-alone driver code used as a methods research vehicle and to verify its underlying classes. These underlying classes are used to construct Implicit Monte Carlo packages for external customers. Milagro-2 represents a design overhaul that allows better parallelism and extensibility. New features in Milagro-2 include verified momentum deposition, restart capability, graphics capability, exact energy conservation, and improved load balancing and parallel efficiency. A users' guide also describes how to configure, make, and run Milagro2.

T.J. Urbatsch; T.M. Evans

2006-02-15T23:59:59.000Z

322

Calculating kinetics parameters and reactivity changes with continuous-energy Monte Carlo  

SciTech Connect (OSTI)

The iterated fission probability interpretation of the adjoint flux forms the basis for a method to perform adjoint weighting of tally scores in continuous-energy Monte Carlo k-eigenvalue calculations. Applying this approach, adjoint-weighted tallies are developed for two applications: calculating point reactor kinetics parameters and estimating changes in reactivity from perturbations. Calculations are performed in the widely-used production code, MCNP, and the results of both applications are compared with discrete ordinates calculations, experimental measurements, and other Monte Carlo calculations.

Kiedrowski, Brian C [Los Alamos National Laboratory; Brown, Forrest B [Los Alamos National Laboratory; Wilson, Paul [UNIV. WISCONSIN

2009-01-01T23:59:59.000Z

323

An Advanced Neutronic Analysis Toolkit with Inline Monte Carlo capability for BHTR Analysis  

SciTech Connect (OSTI)

Monte Carlo capability has been combined with a production LWR lattice physics code to allow analysis of high temperature gas reactor configurations, accounting for the double heterogeneity due to the TRISO fuel. The Monte Carlo code MCNP5 has been used in conjunction with CPM3, which was the testbench lattice physics code for this project. MCNP5 is used to perform two calculations for the geometry of interest, one with homogenized fuel compacts and the other with heterogeneous fuel compacts, where the TRISO fuel kernels are resolved by MCNP5.

William R. Martin; John C. Lee

2009-12-30T23:59:59.000Z

324

Monte Carlo simulations of the HP model (the "Ising model" of protein folding)  

E-Print Network [OSTI]

Using Wang-Landau sampling with suitable Monte Carlo trial moves (pull moves and bond-rebridging moves combined) we have determined the density of states and thermodynamic properties for a short sequence of the HP protein model. For free chains these proteins are known to first undergo a collapse "transition" to a globule state followed by a second "transition" into a native state. When placed in the proximity of an attractive surface, there is a competition between surface adsorption and folding that leads to an intriguing sequence of "transitions". These transitions depend upon the relative interaction strengths and are largely inaccessible to "standard" Monte Carlo methods.

Li, Ying Wai; Landau, David P; 10.1016/j.cpc.2010.12.049

2011-01-01T23:59:59.000Z

325

A study of the contrast of a submerged disc using Monte Carlo techniques  

E-Print Network [OSTI]

A STUDY OF THE CONTRAST OF A SUBMERGED DISC USING MONTE CARLO TECHNIQUES A Thesis by DONALD FRANK HAGAN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... December 1980 Major Subject: Physics A STUDY OF THE CONTRAST OF A SUBMERGED DISC USING MONTE CARLO TECHNIQUES A Thesis by DONALD FRANK HAGAN Approved as to sty1e and content by: (Chairman of Committee) (Head of Department) (Member) (Member...

Hagan, Donald Frank

2012-06-07T23:59:59.000Z

326

Inverted List Kinetic Monte Carlo with Rejection ap-plied to Directed Self-Assembly of Epitaxial Growth  

E-Print Network [OSTI]

Inverted List Kinetic Monte Carlo with Rejection ap- plied to Directed Self-Assembly of Epitaxial of subsequently deposited material using a kinetic Monte Carlo algorithm that combines the use of inverted lists finding is that the relative performance of the inverted list algorithm improves with increasing system

Schulze, Tim

327

Quasi-Monte Carlo simulation of the light environment of plants Mikolaj CieslakA,E,F  

E-Print Network [OSTI]

Quasi-Monte Carlo simulation of the light environment of plants Mikolaj CieslakA,E,F , Christiane-based CARIBU software (Chelle et al. 2004),and we showthat thesetwo programs produceconsistent results. Wealso assessed theperformance oftheRQMCpath tracing algorithm by comparing it with Monte Carlo path tracing

Prusinkiewicz, Przemyslaw

328

Application of collision-based two dimensional Monte Carlo method in a simulated microscale ground water model  

E-Print Network [OSTI]

While the use of Monte Carlo method has been prevalent in nuclear engineering, it has yet to fully blossom in the study of solute transport in porous media. By using an etched-glass micromodel, an attempt is made to apply Monte Carlo method...

Chung, Kiwhan

1996-01-01T23:59:59.000Z

329

Emplacement in an extensional setting of the Mont LozreBorne granitic complex (SE France) inferred from  

E-Print Network [OSTI]

Emplacement in an extensional setting of the Mont Lozère­Borne granitic complex (SE France of the Late Hercynian Mont Lozère­Borne granitic complex (French Massif Central), which consists of several carried out to characterize the internal fabrics of the granitic plutons. Throughout the Pont

Paris-Sud XI, Université de

330

Methodes de Monte Carlo et processus stochastiques. Pierre Del Moral Stefano De Marco Massimiliano Gubinelli Benjamin Jourdain  

E-Print Network [OSTI]

M´ethodes de Monte Carlo et processus stochastiques. Pierre Del Moral ­ Stefano De Marco la m´ethode de Monte Carlo multi-niveaux. L'´equation diff´erentielle stochastique de Black-Scholes d

Del Moral , Pierre

331

Feeding Ecology of 0-Group Sea Bass, Dicentrarchus labrax, in Salt Marshes of Mont Saint Michel Bay (France)  

E-Print Network [OSTI]

bass Dicentrarchus labrax is among the most abundant and exploited fish species of Eu- ropean coastsFeeding Ecology of 0-Group Sea Bass, Dicentrarchus labrax, in Salt Marshes of Mont Saint Michel Bay, France ABSTRACT: 0-group sea bass, Dicentrarchus labrax, colonize intertidal marsh creeks of Mont Saint

Paris-Sud XI, Université de

332

Monte Carlo Posterior Integration in GARCH Peter M uller and Andy Pole  

E-Print Network [OSTI]

Monte Carlo Posterior Integration in GARCH Models Peter M¨ uller and Andy Pole Peter M along both lines to apply to the analysis of GARCH (generalized autoregressive conditional­ tion to GARCH models in Bollerslev (1986). There are now over 300 papers in the mainstream statistics

West, Mike

333

Supertrack Monte Carlo variance reduction experience for non-Boltzmann tallies  

SciTech Connect (OSTI)

This paper applies a recently developed variance reduction technique to the first principles calculations of photon detector responses. This technique makes possible the direct comparison of pulse height calculations with measurements without the need for unfolding techniques. Comparisons are made between several experiments and the calculations to demonstrate the utility of the supertrack Monte Carlo technique for reproducing and interpreting experimental count rate spectra.

Estes, G.P.; Booth, T.E.

1995-02-01T23:59:59.000Z

334

Elsevier Science 1 Use of the GATE Monte Carlo package for dosimetry  

E-Print Network [OSTI]

Elsevier Science 1 Use of the GATE Monte Carlo package for dosimetry applications D. Visvikis, a* M Angeles, USA Abstract One of the roles for MC simulation studies is in the area of dosimetry. A number of different codes dedicated to dosimetry applications are available and widely used today, such as MCNP

Paris-Sud XI, Université de

335

Monte Carlo simulation methodology of the ghost interface theory for the planar surface tension  

E-Print Network [OSTI]

Monte Carlo simulation methodology of the ghost interface theory for the planar surface tension October 2003 A novel ``ghost interface'' expression for the surface tension of a planar liquid coexisting phases. Results generated from the ghost interface theory for the surface tension are presented

Attard, Phil

336

Monte Carlo Simulation of Radiation in Gases with a NarrowBand Model  

E-Print Network [OSTI]

, France (\\Phi) now at the Institute of Energy and Power Plant Technology, TH Darmstadt, 64287 DarmstadtMonte Carlo Simulation of Radiation in Gases with a Narrow­Band Model and a Net is used for simulation of radiative heat transfers in non­gray gases. The proposed procedure is based

Dufresne, Jean-Louis

337

Green's function Monte Carlo calculation for the ground state of helium trimers  

SciTech Connect (OSTI)

The ground state energy of weakly bound boson trimers interacting via Lennard-Jones (12,6) pair potentials is calculated using a Monte Carlo Green's Function Method. Threshold coupling constants for self binding are obtained by extrapolation to zero binding.

Cabral, F.; Kalos, M.H.

1981-02-01T23:59:59.000Z

338

Quasi-Monte Carlo Simulation of the Light Environment of Plants Mikolaj Cieslak1,5  

E-Print Network [OSTI]

Quasi-Monte Carlo Simulation of the Light Environment of Plants Mikolaj Cieslak1,5 , Christiane and Food Research Institute of New Zealand Limited Running Title: QMC Simulation of the Light Environment. In this paper, we will outline the RQMC path tracing algorithm that we use in our light environment program

Lemieux, Christiane

339

Reliability estimation by advanced Monte Carlo E. Zio and N. Pedroni  

E-Print Network [OSTI]

Chapter 1 Reliability estimation by advanced Monte Carlo simulation E. Zio and N. Pedroni Energy for evaluating the reliability of a system, due to the modeling flexibility that it offers indiffer- ently, which points towards the failure domain of interest; the high-dimensional reliability problem

Paris-Sud XI, Université de

340

Combining Monte Carlo Simulations and Options to Manage the Risk of Real  

E-Print Network [OSTI]

of real estate portfolio valuations can be improved through the simultaneous use of Monte Carlo simulations and options theory. Our method considers the options embedded in Continental European lease are more reliable that those usually computed by the traditional method of discounted cash flow. Moreover

Boyer, Edmond

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Optical Monte Carlo modeling of a true port wine stain anatomy  

E-Print Network [OSTI]

of accommodating an arbitrarily complex geometry was used to determine the energy deposition in a true port wineOptical Monte Carlo modeling of a true port wine stain anatomy Jennifer Kehlet Barton, T. Joshua nm. At both wavelengths, the greatest energy deposition occurred in the superficial blood vessels

Barton, Jennifer K.

342

VIM Monte Carlo versus CASMO comparisons for BWR advanced fuel designs  

SciTech Connect (OSTI)

Eigenvalues and two-dimensional fission rate distributions computed with the CASMO-3G lattice physics code and the VIM Monte Carlo Code are compared. The cases assessed are two advanced commercial BWR pin bundle designs. Generally, the two codes show good agreement in K{sub inf}, fission rate distributions, and control rod worths.

Pallotta, A.S. [Commonwealth Edison Co., Chicago, IL (United States); Blomquist, R.N. [Argonne National Lab., IL (United States)

1994-03-01T23:59:59.000Z

343

Quantum Monte Carlo calculations of electronic excitation energies: the case of the singlet n  

E-Print Network [OSTI]

) transition in acrolein Julien Toulouse1 , Michel Caffarel2 , Peter Reinhardt1 , Philip E. Hoggan3 , and C. J-of-the-art quantum Monte Carlo calculations of the singlet n (CO) vertical excitation energy in the acrolein in the acrolein molecule without reoptimization of the determinantal part of the wave function. The acrolein

Paris-Sud XI, Université de

344

Comparison of the Monte Carlo adjoint-weighted and differential operator perturbation methods  

SciTech Connect (OSTI)

Two perturbation theory methodologies are implemented for k-eigenvalue calculations in the continuous-energy Monte Carlo code, MCNP6. A comparison of the accuracy of these techniques, the differential operator and adjoint-weighted methods, is performed numerically and analytically. Typically, the adjoint-weighted method shows better performance over a larger range; however, there are exceptions.

Kiedrowski, Brian C [Los Alamos National Laboratory; Brown, Forrest B [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

345

Simulations of polycrystalline CVD diamond film growth using a simplified Monte Carlo model  

E-Print Network [OSTI]

Simulations of polycrystalline CVD diamond film growth using a simplified Monte Carlo model P online 6 November 2009 Keywords: CVD diamond growth Modelling Nucleation Nanodiamond A simple 1) of a diamond (100) surface. The model considers adsorption, etching/desorption, lattice incorporation

Bristol, University of

346

Sources of Traffic Demand Variability and Use of Monte Carlo for Network Capacity Planning  

E-Print Network [OSTI]

to deal with rightfully angry business and finance teams: physical resources start depreciating the moment the sources of traffic demand variability and dive into Monte-Carlo methodology as an efficient way; throughput; traffic; concurrency; availability; node-and-link model; fast-time simulation; agent

Cortes, Corinna

347

Performance Characteristics of Cathode Materials for Lithium-Ion Batteries: A Monte Carlo Strategy  

E-Print Network [OSTI]

Performance Characteristics of Cathode Materials for Lithium-Ion Batteries: A Monte Carlo Strategy to study the performance of cathode materials in lithium-ion batteries. The methodology takes into account. Published September 26, 2008. Lithium-ion batteries are state-of-the-art power sources1 for por- table

Subramanian, Venkat

348

Monte Carlo calculations of pair production in high-intensity laser-plasma interactions  

E-Print Network [OSTI]

Gamma-ray and electron-positron pair production will figure prominently in laser-plasma experiments with next generation lasers. Using a Monte Carlo approach we show that straggling effects arising from the finite recoil an electron experiences when it emits a high energy photon, increase the number of pairs produced on further interaction with the laser fields.

Roland Duclous; John Kirk; Anthony Bell

2010-10-21T23:59:59.000Z

349

Monte Carlo Characterization of a Pulsed Laser-Wakefield Driven Monochromatic  

E-Print Network [OSTI]

Monte Carlo Characterization of a Pulsed Laser-Wakefield Driven Monochromatic X-Ray Source S. D determination of the incident X-ray energy by using unfolding techniques. I. INTRODUCTION HE Diocles laser light from the same laser system, producing monochromatic X-rays with energy and spectral width

Umstadter, Donald

350

A Positive-Weight Next-to-Leading-Order Monte Carlo for Heavy Flavour Hadroproduction  

E-Print Network [OSTI]

We present a next-to-leading order calculation of heavy flavour production in hadronic collisions that can be interfaced to shower Monte Carlo programs. The calculation is performed in the context of the POWHEG method. It is suitable for the computation of charm, bottom and top hadroproduction. In the case of top production, spin correlations in the decay products are taken into account.

Stefano Frixione; Paolo Nason; Giovanni Ridolfi

2007-09-22T23:59:59.000Z

351

Direct Simulation Monte Carlo of Inductively Coupled Plasma and Comparison with Experiments  

E-Print Network [OSTI]

Direct Simulation Monte Carlo of Inductively Coupled Plasma and Comparison with Experiments Justine of Chemical Engineering, University of Houston, Houston, Texas 77204-4 792, USA ABSTRACT Direct simulation-density inductively coupled reactor with chlorine (electronegative) chemistry. Electron density and temperature were

Economou, Demetre J.

352

Optimisation of masked ion irradiation damage profiles in YBCO thin films by Monte Carlo simulation  

E-Print Network [OSTI]

Optimisation of masked ion irradiation damage profiles in YBCO thin films by Monte Carlo simulation production with a given mask structure. The results suggest that minimum ion scattering broadening tails with beam energy up to a few hundred keV, though the throughput is intrinsically low [1]. A combination

Webb, Roger P.

353

Use of single scatter electron monte carlo transport for medical radiation sciences  

DOE Patents [OSTI]

The single scatter Monte Carlo code CREEP models precise microscopic interactions of electrons with matter to enhance physical understanding of radiation sciences. It is designed to simulate electrons in any medium, including materials important for biological studies. It simulates each interaction individually by sampling from a library which contains accurate information over a broad range of energies.

Svatos, Michelle M. (Oakland, CA)

2001-01-01T23:59:59.000Z

354

Tir--part Les espaces boiss du flanc nord-ouest du mont Royal  

E-Print Network [OSTI]

milieu de la plaine du Saint-Laurent et d'une ville fortement urbanisée, le mont Royal constitue un'arrondissement historique et naturel. Par cette double désignation, il reconnaît que les qualités natu- relles et

355

Equilibrium polymerization in sulphur: Monte Carlo simulations with a density functional based force field  

E-Print Network [OSTI]

Equilibrium polymerization in sulphur: Monte Carlo simulations with a density functional based Messina, I-98166 Messina, Italy The equilibrium polymerization of sulphur is investigated by a combination leading to polymerization, and the results for the cohesive energy, structural and vibrational properties

356

Monte Carlo Calculations of the Intrinsic Detector Backgrounds for the Karlsruhe Tritium Neutrino Experiment  

E-Print Network [OSTI]

Monte Carlo Calculations of the Intrinsic Detector Backgrounds for the Karlsruhe Tritium Neutrino of the Intrinsic Detector Backgrounds for the Karlsruhe Tritium Neutrino Experiment Michelle L. Leber Chair of the Supervisory Committee: Professor John F. Wilkerson Physics The Karlsruhe Tritium Neutrino Experiment (KATRIN

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

357

Collective enhancement of nuclear state densities by the shell model Monte Carlo approach  

E-Print Network [OSTI]

The shell model Monte Carlo (SMMC) approach allows for the microscopic calculation of statistical and collective properties of heavy nuclei using the framework of the configuration-interaction shell model in very large model spaces. We present recent applications of the SMMC method to the calculation of state densities and their collective enhancement factors in rare-earth nuclei.

Özen, C; Nakada, H

2015-01-01T23:59:59.000Z

358

Comparison of Monte-Carlo and Einstein methods in the light-gas interactions  

E-Print Network [OSTI]

To study the propagation of light in nebulae, many astrophysicists use a Monte-Carlo computation which does not take interferences into account. Replacing the wrong method by Einstein coefficients theory gives, on an example, a theoretical spectrum much closer to the observed one.

Jacques Moret-Bailly

2010-01-18T23:59:59.000Z

359

SCALE Continuous-Energy Monte Carlo Depletion with Parallel KENO in TRITON  

SciTech Connect (OSTI)

The TRITON sequence of the SCALE code system is a powerful and robust tool for performing multigroup (MG) reactor physics analysis using either the 2-D deterministic solver NEWT or the 3-D Monte Carlo transport code KENO. However, as with all MG codes, the accuracy of the results depends on the accuracy of the MG cross sections that are generated and/or used. While SCALE resonance self-shielding modules provide rigorous resonance self-shielding, they are based on 1-D models and therefore 2-D or 3-D effects such as heterogeneity of the lattice structures may render final MG cross sections inaccurate. Another potential drawback to MG Monte Carlo depletion is the need to perform resonance self-shielding calculations at each depletion step for each fuel segment that is being depleted. The CPU time and memory required for self-shielding calculations can often eclipse the resources needed for the Monte Carlo transport. This summary presents the results of the new continuous-energy (CE) calculation mode in TRITON. With the new capability, accurate reactor physics analyses can be performed for all types of systems using the SCALE Monte Carlo code KENO as the CE transport solver. In addition, transport calculations can be performed in parallel mode on multiple processors.

Goluoglu, Sedat [ORNL] [ORNL; Bekar, Kursat B [ORNL] [ORNL; Wiarda, Dorothea [ORNL] [ORNL

2012-01-01T23:59:59.000Z

360

Composition of Fish Communities in a European Macrotidal Salt Marsh (the Mont Saint-Michel Bay,  

E-Print Network [OSTI]

Composition of Fish Communities in a European Macrotidal Salt Marsh (the Mont Saint-Michel Bay At least 100 fish species are known to be present in the intertidal areas (estuaries, mudflats and salt, such as estuaries and lagoons, play a nursery role for many fish species. However, in Europe little attention has

Boyer, Edmond

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Path-Integral Monte Carlo And The Squeezed Trapped Bose-Einstein Gas  

E-Print Network [OSTI]

Path-Integral Monte Carlo And The Squeezed Trapped Bose-Einstein Gas Juan Pablo Fernández1 the gas becomes effectively two-dimensional (2D). We confirm the plausibility of this result by performing different estimates for the condensate fraction. For the ideal gas, we find that the PIMC column density

Mullin, William J.

362

The S/sub N//Monte Carlo response matrix hybrid method  

SciTech Connect (OSTI)

A hybrid method has been developed to iteratively couple S/sub N/ and Monte Carlo regions of the same problem. This technique avoids many of the restrictions and limitations of previous attempts to do the coupling and results in a general and relatively efficient method. We demonstrate the method with some simple examples.

Filippone, W.L.; Alcouffe, R.E.

1987-01-01T23:59:59.000Z

363

Path Integral Monte Carlo Simulation of the Low-Density Hydrogen Plasma B. Militzer y  

E-Print Network [OSTI]

Path Integral Monte Carlo Simulation of the Low-Density Hydrogen Plasma B. Militzer y Lawrence to calculate the equilibrium properties of hydrogen in the density and temperature range of 9:83 #2; 10 4 #20 surface. We calculate the equation of state and compare with other models for hydrogen valid

Militzer, Burkhard

364

New variational Monte Carlo method with an energy variance extrapolation for large-scale shell-model calculations  

E-Print Network [OSTI]

We propose a new variational Monte Carlo (VMC) method with an energy variance extrapolation for large-scale shell-model calculations. This variational Monte Carlo is a stochastic optimization method with a projected correlated condensed pair state as a trial wave function, and is formulated with the M-scheme representation of projection operators, the Pfaffian and the Markov-chain Monte Carlo (MCMC). Using this method, we can stochastically calculate approximated yrast energies and electro-magnetic transition strengths. Furthermore, by combining this VMC method with energy variance extrapolation, we can estimate exact shell-model energies.

Takahiro Mizusaki; Noritaka Shimizu

2012-01-27T23:59:59.000Z

365

A comparison of maximum likelihood and other estimators of eigenvalues from several correlated Monte Carlo samples  

SciTech Connect (OSTI)

The maximum likelihood method for the multivariate normal distribution is applied to the case of several individual eigenvalues. Correlated Monte Carlo estimates of the eigenvalue are assumed to follow this prescription and aspects of the assumption are examined. Monte Carlo cell calculations using the SAM-CE and VIM codes for the TRX-1 and TRX-2 benchmark reactors, and SAM-CE full core results are analyzed with this method. Variance reductions of a few percent to a factor of 2 are obtained from maximum likelihood estimation as compared with the simple average and the minimum variance individual eigenvalue. The numerical results verify that the use of sample variances and correlation coefficients in place of the corresponding population statistics still leads to nearly minimum variance estimation for a sufficient number of histories and aggregates.

Beer, M.

1980-12-01T23:59:59.000Z

366

Monte-Carlo Simulations for the optimisation of a TOF-MIEZE Instrument  

E-Print Network [OSTI]

The MIEZE (Modulation of Intensity with Zero Effort) technique is a variant of neutron resonance spin echo (NRSE), which has proven to be a unique neutron scattering technique for measuring with high energy resolution in magnetic fields. Its limitations in terms of flight path differences have already been investigated analytically for neutron beams with vanishing divergence. In the present work Monte-Carlo simulations for quasi-elastic MIEZE experiments taking into account beam divergence as well as the sample dimensions are presented. One application of the MIEZE technique could be a dedicated NRSE-MIEZE instrument at the European Spallation Source (ESS) in Sweden. The optimisation of a particular design based on Montel mirror optics with the help of Monte Carlo simulations will be discussed here in detail.

Weber, T; Georgii, R; Häußler, W; Weichselbaumer, S; Böni, P; 10.1016/j.nima.2013.03.010

2013-01-01T23:59:59.000Z

367

A user-friendly, graphical interface for the Monte Carlo neutron optics code MCLIB  

SciTech Connect (OSTI)

The authors describe a prototype of a new user interface for the Monte Carlo neutron optics simulation program MCLIB. At this point in its development the interface allows the user to define an instrument as a set of predefined instrument elements. The user can specify the intrinsic parameters of each element, its position and orientation. The interface then writes output to the MCLIB package and starts the simulation. The present prototype is an early development stage of a comprehensive Monte Carlo simulations package that will serve as a tool for the design, optimization and assessment of performance of new neutron scattering instruments. It will be an important tool for understanding the efficacy of new source designs in meeting the needs of these instruments.

Thelliez, T.; Daemen, L.; Hjelm, R.P. [Los Alamos National Lab., NM (United States); Seeger, P.A. [Seeger (Phil A.), Los Alamos, NM (United States)

1995-12-01T23:59:59.000Z

368

Monte Carlo study of the performance of a time-of-flight multichopper spectrometer  

SciTech Connect (OSTI)

The Monte Carlo method is a powerful technique for neutron transport studies. While it has been applied for many years to the study of nuclear systems, there are few codes available for neutron transport in the optical regime. The recent surge of interest in so-called next generation spallation neutron sources and the desire to design new and optimized instruments for these facilities has led us to develop a Monte Carlo code geared toward the simulation of neutron scattering instruments. The time-of-flight multichopper spectrometer, of which IN5 at the ILL is the prototypical example, is the first spectrometer studied with the code. Some of the results of a comparison between the IN5 performance at a reactor and at a Long Pulse Spallation Source (LPSS) are summarized here.

Daemen, L.L.; Eckert, J.; Pynn, R. [and others

1995-12-01T23:59:59.000Z

369

A Monte Carlo simulation for kinetic chemotaxis models: an application to the traveling population wave  

E-Print Network [OSTI]

A Monte Carlo simulation for the chemotactic bacteria is developed on the basis of the kinetic modeling, i.e., the Boltzmann transport equation, and applied to the one-dimensional traveling population wave in a micro channel.In this method, the Monte Carlo method, which calculates the run-and-tumble motions of bacteria, is coupled with a finite volume method to solve the macroscopic transport of the chemical cues in the field. The simulation method can successfully reproduce the traveling population wave of bacteria which was observed experimentally. The microscopic dynamics of bacteria, e.g., the velocity autocorrelation function and velocity distribution function of bacteria, are also investigated. It is found that the bacteria which form the traveling population wave create quasi-periodic motions as well as a migratory movement along with the traveling population wave. Simulations are also performed with changing the sensitivity and modulation parameters in the response function of bacteria. It is found th...

Yasuda, Shugo

2015-01-01T23:59:59.000Z

370

Monte Carol-Based Dosimetry of Beta-Emitters for Intravascular Brachytherapy  

SciTech Connect (OSTI)

Monte Carlo simulations for radiation dosimetry and the experimental verifications of the simulations have been developed for the treatment geometry of intravascular brachytherapy, a form of radionuclide therapy for occluded coronary disease (restenosis). Monte Carlo code, MCNP4C, has been used to calculate the radiation dose from the encapsulated array of B-emitting seeds (Sr/Y-source train). Solid water phantoms have been fabricated to measure the dose on the radiochromic films that were exposed to the beta source train for both linear and curved coronary vessel geometries. While the dose difference for the 5-degree curved vessel at the prescription point of f+2.0 mm is within the 10% guideline set by the AAPM, however, the difference increased dramatically to 16.85% for the 10-degree case which requires additional adjustment for the acceptable dosimetry planning. The experimental dose measurements agree well with the simulation results

Choi, C.K.

2002-06-25T23:59:59.000Z

371

Calculating alpha Eigenvalues in a Continuous-Energy Infinite Medium with Monte Carlo  

SciTech Connect (OSTI)

The {alpha} eigenvalue has implications for time-dependent problems where the system is sub- or supercritical. We present methods and results from calculating the {alpha}-eigenvalue spectrum for a continuous-energy infinite medium with a simplified Monte Carlo transport code. We formulate the {alpha}-eigenvalue problem, detail the Monte Carlo code physics, and provide verification and results. We have a method for calculating the {alpha}-eigenvalue spectrum in a continuous-energy infinite-medium. The continuous-time Markov process described by the transition rate matrix provides a way of obtaining the {alpha}-eigenvalue spectrum and kinetic modes. These are useful for the approximation of the time dependence of the system.

Betzler, Benjamin R. [Los Alamos National Laboratory; Kiedrowski, Brian C. [Los Alamos National Laboratory; Brown, Forrest B. [Los Alamos National Laboratory; Martin, William R. [Los Alamos National Laboratory

2012-09-04T23:59:59.000Z

372

Study of nuclear pairing with Configuration-Space Monte-Carlo approach  

E-Print Network [OSTI]

Pairing correlations in nuclei play a decisive role in determining nuclear drip-lines, binding energies, and many collective properties. In this work a new Configuration-Space Monte-Carlo (CSMC) method for treating nuclear pairing correlations is developed, implemented, and demonstrated. In CSMC the Hamiltonian matrix is stochastically generated in Krylov subspace, resulting in the Monte-Carlo version of Lanczos-like diagonalization. The advantages of this approach over other techniques are discussed; the absence of the fermionic sign problem, probabilistic interpretation of quantum-mechanical amplitudes, and ability to handle truly large-scale problems with defined precision and error control, are noteworthy merits of CSMC. The features of our CSMC approach are shown using models and realistic examples. Special attention is given to difficult limits: situations with non-constant pairing strengths, cases with nearly degenerate excited states, limits when pairing correlations in finite systems are weak, and pr...

Lingle, Mark

2015-01-01T23:59:59.000Z

373

Rao-Blackwellised Interacting Markov Chain Monte Carlo for Electromagnetic Scattering Inversion  

E-Print Network [OSTI]

The following electromagnetism (EM) inverse problem is addressed. It consists in estimating local radioelectric properties of materials recovering an object from the global EM scattering measurement, at various incidences and wave frequencies. This large scale ill-posed inverse problem is explored by an intensive exploitation of an efficient 2D Maxwell solver, distributed on High Performance Computing (HPC) machines. Applied to a large training data set, a statistical analysis reduces the problem to a simpler probabilistic metamodel, on which Bayesian inference can be performed. Considering the radioelectric properties as a dynamic stochastic process, evolving in function of the frequency, it is shown how advanced Markov Chain Monte Carlo methods, called Sequential Monte Carlo (SMC) or interacting particles, can provide estimations of the EM properties of each material, and their associated uncertainties.

Giraud, François

2012-01-01T23:59:59.000Z

374

MCAMC: An Advanced Algorithm for Kinetic Monte Carlo Simulations: from Magnetization Switching to Protein Folding  

E-Print Network [OSTI]

We present the Monte Carlo with Absorbing Markov Chains (MCAMC) method for extremely long kinetic Monte Carlo simulations. The MCAMC algorithm does not modify the system dynamics. It is extremely useful for models with discrete state spaces when low-temperature simulations are desired. To illustrate the strengths and limitations of this algorithm we introduce a simple model involving random walkers on an energy landscape. This simple model has some of the characteristics of protein folding and could also be experimentally realizable in domain motion in nanoscale magnets. We find that even the simplest MCAMC algorithm can speed up calculations by many orders of magnitude. More complicated MCAMC simulations can gain further increases in speed by orders of magnitude.

M. A. Novotny; Shannon M. Wheeler

2002-11-02T23:59:59.000Z

375

Using high performance computing and Monte Carlo simulation for pricing american options  

E-Print Network [OSTI]

High performance computing (HPC) is a very attractive and relatively new area of research, which gives promising results in many applications. In this paper HPC is used for pricing of American options. Although the American options are very significant in computational finance; their valuation is very challenging, especially when the Monte Carlo simulation techniques are used. For getting the most accurate price for these types of options we use Quasi Monte Carlo simulation, which gives the best convergence. Furthermore, this algorithm is implemented on both GPU and CPU. Additionally, the CUDA architecture is used for harnessing the power and the capability of the GPU for executing the algorithm in parallel which is later compared with the serial implementation on the CPU. In conclusion this paper gives the reasons and the advantages of applying HPC in computational finance.

Cvetanoska, Verche

2012-01-01T23:59:59.000Z

376

Monte Carlo validation experiments for the gas Cherenkov detectors at the National Ignition Facility and Omega  

SciTech Connect (OSTI)

The gas Cherenkov detectors at NIF and Omega measure several ICF burn characteristics by detecting multi-MeV nuclear ? emissions from the implosion. Of primary interest are ? bang-time (GBT) and burn width defined as the time between initial laser-plasma interaction and peak in the fusion reaction history and the FWHM of the reaction history respectively. To accurately calculate such parameters the collaboration relies on Monte Carlo codes, such as GEANT4 and ACCEPT, for diagnostic properties that cannot be measured directly. This paper describes a series of experiments performed at the High Intensity ? Source (HI?S) facility at Duke University to validate the geometries and material data used in the Monte Carlo simulations. Results published here show that model-driven parameters such as intensity and temporal response can be used with less than 50% uncertainty for all diagnostics and facilities.

Rubery, M. S.; Horsfield, C. J. [Plasma Physics Department, AWE plc, Reading RG7 4PR (United Kingdom)] [Plasma Physics Department, AWE plc, Reading RG7 4PR (United Kingdom); Herrmann, H.; Kim, Y.; Mack, J. M.; Young, C.; Evans, S.; Sedillo, T.; McEvoy, A.; Caldwell, S. E. [Plasma Physics Department, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Plasma Physics Department, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Grafil, E.; Stoeffl, W. [Physics, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Physics, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Milnes, J. S. [Photek Limited UK, 26 Castleham Road, St. Leonards-on-sea TN38 9NS (United Kingdom)] [Photek Limited UK, 26 Castleham Road, St. Leonards-on-sea TN38 9NS (United Kingdom)

2013-07-15T23:59:59.000Z

377

The Metropolis Monte Carlo method with CUDA enabled Graphic Processing Units  

SciTech Connect (OSTI)

We present a CPU–GPU system for runtime acceleration of large molecular simulations using GPU computation and memory swaps. The memory architecture of the GPU can be used both as container for simulation data stored on the graphics card and as floating-point code target, providing an effective means for the manipulation of atomistic or molecular data on the GPU. To fully take advantage of this mechanism, efficient GPU realizations of algorithms used to perform atomistic and molecular simulations are essential. Our system implements a versatile molecular engine, including inter-molecule interactions and orientational variables for performing the Metropolis Monte Carlo (MMC) algorithm, which is one type of Markov chain Monte Carlo. By combining memory objects with floating-point code fragments we have implemented an MMC parallel engine that entirely avoids the communication time of molecular data at runtime. Our runtime acceleration system is a forerunner of a new class of CPU–GPU algorithms exploiting memory concepts combined with threading for avoiding bus bandwidth and communication. The testbed molecular system used here is a condensed phase system of oligopyrrole chains. A benchmark shows a size scaling speedup of 60 for systems with 210,000 pyrrole monomers. Our implementation can easily be combined with MPI to connect in parallel several CPU–GPU duets. -- Highlights: •We parallelize the Metropolis Monte Carlo (MMC) algorithm on one CPU—GPU duet. •The Adaptive Tempering Monte Carlo employs MMC and profits from this CPU—GPU implementation. •Our benchmark shows a size scaling-up speedup of 62 for systems with 225,000 particles. •The testbed involves a polymeric system of oligopyrroles in the condensed phase. •The CPU—GPU parallelization includes dipole—dipole and Mie—Jones classic potentials.

Hall, Clifford [Computational Materials Science Center, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States) [Computational Materials Science Center, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States); School of Physics, Astronomy, and Computational Sciences, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States); Ji, Weixiao [Computational Materials Science Center, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States)] [Computational Materials Science Center, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States); Blaisten-Barojas, Estela, E-mail: blaisten@gmu.edu [Computational Materials Science Center, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States) [Computational Materials Science Center, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States); School of Physics, Astronomy, and Computational Sciences, George Mason University, 4400 University Dr., Fairfax, VA 22030 (United States)

2014-02-01T23:59:59.000Z

378

Radiative transfer in the earth's atmosphere-ocean system using Monte Carlo techniques  

E-Print Network [OSTI]

are described in the next chapter. The books by Morgan and Hammersley and Handscomb describe the theory and some methods of variance reduction for general applications. One item that is required of any Monte Carlo simulation is a supply of randoni numbers... be checked through modification of the model since the same sequeiice of random numbers may be generated repeatedly. Discussions on the properties ot' random nuinbers and their generation may be found in the books by Morgan' and Hammersley and Handscomb...

Bradley, Paul Andrew

2012-06-07T23:59:59.000Z

379

Using Markov chain Monte Carlo methods for estimating parameters with gravitational radiation data  

E-Print Network [OSTI]

We present a Bayesian approach to the problem of determining parameters for coalescing binary systems observed with laser interferometric detectors. By applying a Markov Chain Monte Carlo (MCMC) algorithm, specifically the Gibbs sampler, we demonstrate the potential that MCMC techniques may hold for the computation of posterior distributions of parameters of the binary system that created the gravity radiation signal. We describe the use of the Gibbs sampler method, and present examples whereby signals are detected and analyzed from within noisy data.

Nelson Christensen; Renate Meyer

2001-02-05T23:59:59.000Z

380

Monte Carlo Solutions for Selected Problems in Gamma-Ray Spectrometry and Nuclear Activation Analysis  

SciTech Connect (OSTI)

A comprehensive calibration of gamma-ray spectrometers cannot be obtained purely on experimental basis. Problems like self-attenuation effects, coincidence-summing effects and non-uniform source distribution (resulting e.g. from neutron self-shielding in NAA) can be efficiently solved by Monte Carlo simulation. The application of the GESPECOR code to these problems is presented and the associated uncertainty is discussed.

Sima, Octavian [Physics Department, University of Bucharest, Bucharest-Magurele, POBoxMG-11 RO-077125 (Romania)

2008-08-14T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

The role of diagonalization within a diagonalization/Monte Carlo scheme  

E-Print Network [OSTI]

We discuss a method called quasi-sparse eigenvector diagonalization which finds the most important basis vectors of the low energy eigenstates of a quantum Hamiltonian. It can operate using any basis, either orthogonal or non-orthogonal, and any sparse Hamiltonian, either Hermitian, non-Hermitian, finite-dimensional, or infinite-dimensional. The method is part of a new computational approach which combines both diagonalization and Monte Carlo techniques.

Dean Lee

2000-10-31T23:59:59.000Z

382

Calculation of shielding door thicknesses for radiation therapy facilities using the ITS Monte Carlo program  

SciTech Connect (OSTI)

Shielding calculations for door thicknesses for megavoltage radiotherapy facilities with mazes are generally straightforward. To simplify the calculations, the standard formalism adopts several approximations relating to the average beam path, scattering coefficients, and the mean energy of the spectrum of scattered radiation. To test the accuracy of these calculations, the Monte Carlo program, ITS, was applied to this problem by determining the dose and energy spectrum of the radiation at the door for 4- and 10-MV bremsstrahlung beams incident on a phantom at isocenter. This was performed for mazes, one termed 'standard' and the other a shorter maze where the primary beam is incident on the wall adjacent to the door. The peak of the photon-energy spectrum at the door was found to be the same for both types of maze, independent of primary beam energy, and also, in the case of the conventional maze, of the primary beam orientation. The spectrum was harder for the short maze and for 10 MV vs. 4 MV. The thickness of the lead door for a short maze configuration was 1.5 cm for 10 MV and 1.2 cm for 4 MV vs. approximately less than 1 mm for a conventional maze. For the conventional maze, the Monte Carlo calculation predicts the dose at the door to be lower than given by NCRP 49 and NCRP 51 by about a factor of 2 at 4 MV but to be the same at 10 MV. For the short maze, the Monte Carlo predicts the dose to be a factor of 3 lower for 4 MV and about a factor of 1.5 lower for 10 MV. Experimental results support the Monte Carlo findings for the short maze.

Biggs, P.J. (Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston (United States))

1991-10-01T23:59:59.000Z

383

Using exploratory data analysis modified Box Plots to enhance Monte Carlo simulated Range Estimating Decision Technology  

E-Print Network [OSTI]

of the thesis is written with the intent of reviewing some of the significant pieces of literature relating to Monte Carlo simulated REDT and exploratory data analysis Box Plots. In 1964 David Hertz published an article in the Harvard Business Review... entitled, "Risk Analysis in Capital Investment" (Hertz 1964). While this article does not directly discuss range estimating, it is the foundation for the current REDT theory. In his atticle, Hertz discussed the problems associated with estimating...

Clutter, David John

1992-01-01T23:59:59.000Z

384

Hybrid Monte Carlo with Wilson Dirac operator on the Fermi GPU  

E-Print Network [OSTI]

In this article we present our implementation of a Hybrid Monte Carlo algorithm for Lattice Gauge Theory using two degenerate flavours of Wilson-Dirac fermions on a Fermi GPU. We find that using registers instead of global memory speeds up the code by almost an order of magnitude. To map the array variables to scalars, so that the compiler puts them in the registers, we use code generators. Our final program is more than 10 times faster than a generic single CPU.

Abhijit Chakrabarty; Pushan Majumdar

2012-07-10T23:59:59.000Z

385

A unified Monte Carlo approach to fast neutron cross section data evaluation.  

SciTech Connect (OSTI)

A unified Monte Carlo (UMC) approach to fast neutron cross section data evaluation that incorporates both model-calculated and experimental information is described. The method is based on applications of Bayes Theorem and the Principle of Maximum Entropy as well as on fundamental definitions from probability theory. This report describes the formalism, discusses various practical considerations, and examines a few numerical examples in some detail.

Smith, D.; Nuclear Engineering Division

2008-03-03T23:59:59.000Z

386

Hybrid Monte Carlo with Wilson Dirac operator on the Fermi GPU  

E-Print Network [OSTI]

In this article we present our implementation of a Hybrid Monte Carlo algorithm for Lattice Gauge Theory using two degenerate flavours of Wilson-Dirac fermions on a Fermi GPU. We find that using registers instead of global memory speeds up the code by almost an order of magnitude. To map the array variables to scalars, so that the compiler puts them in the registers, we use code generators. Our final program is more than 10 times faster than a generic single CPU.

Chakrabarty, Abhijit

2012-01-01T23:59:59.000Z

387

Monte Carlo radiative transfer simulation for the near-ocean-surface high-resolution downwelling irradiance statistics  

E-Print Network [OSTI]

We present a numerical study of the near-surface underwater solar light statistics using the state-of-the-art Monte Carlo radiative transfer (RT) simulations in the coupled atmosphere-ocean system. Advanced variance-reduction ...

Xu, Zao

388

Spatial homogenization of thermal feedback regions in Monte Carlo reactor calculations  

SciTech Connect (OSTI)

An integrated thermal-hydraulic feedback module has previously been developed for the Monte Carlo transport solver, MC21. The module incorporates a flexible input format that allows the user to describe heat transfer and coolant flow paths within the geometric model at any level of spatial detail desired. The effect that the varying levels of spatial homogenization of thermal regions has on the accuracy of the Monte Carlo simulations is examined in this study. Six thermal feedback mappings are constructed from the same geometric model of the Calvert Cliffs core. The spatial homogenization of the thermal regions is varied, giving each scheme a different level of detail, and the adequacy of the spatial homogenization is determined based on the eigenvalue produced by each Monte Carlo calculation. The purpose of these numerical experiments is to determine the level of detail necessarily to accurately capture the thermal feedback effect on reactivity. Several different core models are considered: axial-flow only, axial and lateral flow, asymmetry due to control rod insertion, and fuel heating (temperature -dependent cross sections). The thermal results generated by the MC21 thermal feedback module are consistent with expectations. Based upon the numerical experiments conducted it is concluded that the amount of spatial detail necessary to accurately capture the feedback effect on reactivity is relatively small. Homogenization at the assembly level for the Calvert Cliffs PWR model results in a similar power defect to that calculated with individual pin-cells modeled as explicit thermal regions. (authors)

Hanna, B. R.; Gill, D. F.; Griesheimer, D. P. [Bertis Atomic Power Laboratory, Bechtel Marine Propulsion Corporation, P.O. Box 79, West Mifflin, PA 15122 (United States)

2012-07-01T23:59:59.000Z

389

Magnetic stratigraphy and biostratigraphy of the Piacenzian (Upper Pliocene) at Monte San Nicola (Sicily)  

SciTech Connect (OSTI)

During the Neogene, the Mediterranean was a rather unique biogeographic province. For this reason, first and last occurrences of Neogene species recorded in the Mediterranean region may not be synchronous with those recorded in the open oceans. This has important implications as most of the Neogene stage boundaries are defined on the basis of Mediterranean type sections. The most direct way to determine the relative timing of Mediterranean and open ocean datums is through correlation with the polarity time scale. Such correlations are not available for the Mediterranean Pliocene. The Trubi pelagic limestones and Monte narbone marls which characterize the SicilianPliocene are not ideal for magnetic stratigraphy due to weak remnant intensities and an ubiquitous normal polarity overprint. However, at Monte San Nicola, a magnetic stratigraphy has been resolved by stepwise demagnetization in small temperature increments. The upper and lower bounds of the Gauss Epoch, and the Mammoth and Kaena polarity events can be correlated to well defined planktonic foraminiferal and calcareous nannofossil datums. Hence the synchronism of these datums between the Mediterranean and the open ocean can be tested. The most notable discrepancy is in the last occurrence of G. margaritae which occurs at the base of the Gauss in most open marine sections, but is found at the top of the Gilbert at Monte San Nicola.

Channell, J.E.T.; Sprovieri, R.; Di Stefano, E.

1985-01-01T23:59:59.000Z

390

Nonequilibrium candidate Monte Carlo: A new tool for efficient equilibrium simulation  

SciTech Connect (OSTI)

Metropolis Monte Carlo simulation is a powerful tool for studying the equilibrium properties of matter. In complex condensed-phase systems, however, it is difficult to design Monte Carlo moves with high acceptance probabilities that also rapidly sample uncorrelated configurations. Here, we introduce a new class of moves based on nonequilibrium dynamics: candidate configurations are generated through a finite-time process in which a system is actively driven out of equilibrium, and accepted with criteria that preserve the equilibrium distribution. The acceptance rule is similar to the Metropolis acceptance probability, but related to the nonequilibrium work rather than the instantaneous energy difference. Our method is applicable to sampling from both a single thermodynamic state or a mixture of thermodynamic states, and allows both coordinates and thermodynamic parameters to be driven in nonequilibrium proposals. While generating finite-time switching trajectories incurs an additional cost, driving some degrees of freedom while allowing others to evolve naturally can lead to large enhancements in acceptance probabilities, greatly reducing structural correlation times. Using nonequilibrium driven processes vastly expands the repertoire of useful Monte Carlo proposals in simulations of dense solvated systems.

Nilmeier, Jerome P.; Crooks, Gavin E.; Minh, David D. L.; Chodera, John D.

2011-11-08T23:59:59.000Z

391

MCNPX Monte Carlo burnup simulations of the isotope correlation experiments in the NPP obrigheim.  

SciTech Connect (OSTI)

This paper describes the simulation work of the Isotope Correlation Experiment (ICE) using the MCNPX Monte Carlo computer code package. The Monte Carlo simulation results are compared with the ICE-Experimental measurements for burnup up to 30 GWD/t. The comparison shows the good capabilities of the MCNPX computer code package for predicting the depletion of the uranium fuel and the buildup of the plutonium isotopes in a PWR thermal reactor. The Monte Carlo simulation results show also good agreements with the experimental data for calculating several long-lived and stable fission products. However, for the americium and curium actinides, it is difficult to judge the predication capabilities for these actinides due to the large uncertainties in the ICE-Experimental data. In the MCNPX numerical simulations, a pin cell model is utilized to simulate the fuel lattice of the nuclear power reactor. Temperature dependent libraries based on JEFF3.1 nuclear data files are utilized for the calculations. In addition, temperature dependent libraries based ENDF/B-VII nuclear data files are utilized and the obtained results are very close to the JEFF3.1 results, except for {approx}10% differences in the prediction of the minor actinide isotopes buildup.

Cao, Y.; Gohar, Y.; Broeders, C. (Nuclear Engineering Division); (Inst. for Neutron Physics and Reactor Technology)

2010-10-01T23:59:59.000Z

392

Monte Carlo depletion calculations using VESTA 2.1 new features and perspectives  

SciTech Connect (OSTI)

VESTA is a Monte Carlo depletion interface code that is currently under development at IRSN. With VESTA, the emphasis lies on both accuracy and performance, so that the code will be capable of providing accurate and complete answers in an acceptable amount of time compared to other Monte Carlo depletion codes. From its inception, VESTA is intended to be a generic interface code so that it will ultimately be capable of using any Monte-Carlo code or depletion module and that can be tailored to the users needs. A new version of the code (version 2.1.x) will be released in 2012. The most important additions to the code are a burn up dependent isomeric branching ratio treatment to improve the prediction of metastable nuclides such as {sup 242m}Am and the integration of the PHOENIX point depletion module (also developed at IRSN) to overcome some of the limitations of the ORIGEN 2.2 module. The task of extracting and visualising the basic results and also the calculation of physical quantities or other data that can be derived from the basic output provided by VESTA will be the task of the AURORA depletion analysis tool which will be released at the same time as VESTA 2.1.x. The experimental validation database was also extended for this new version and it now contains a total of 35 samples with chemical assay data and 34 assembly decay heat measurements. (authors)

Haeck, W.; Cochet, B.; Aguiar, L. [Institut de Radioprotection et de Surete Nucleaire IRSN, BP 17, 92262 Fontenay-aux-Roses Cedex (France)

2012-07-01T23:59:59.000Z

393

Monte Carlo Study of Patchy Nanostructures Self-Assembled from a Single Multiblock Chain  

E-Print Network [OSTI]

We present a lattice Monte Carlo simulation for a multiblock copolymer chain of length N=240 and microarchitecture $(10-10)_{12}$.The simulation was performed using the Monte Carlo method with the Metropolis algorithm. We measured average energy, heat capacity, the mean squared radius of gyration, and the histogram of cluster count distribution. Those quantities were investigated as a function of temperature and incompatibility between segments, quantified by parameter {\\omega}. We determined the temperature of the coil-globule transition and constructed the phase diagram exhibiting a variety of patchy nanostructures. The presented results yield a qualitative agreement with those of the off-lattice Monte Carlo method reported earlier, with a significant exception for small incompatibilities,{\\omega}, and low temperatures, where 3-cluster patchy nanostructures are observed in contrast to the 2-cluster structures observed for the off-lattice $(10-10)_{12}$ chain. We attribute this difference to a considerable stiffness of lattice chains in comparison to that of the off-lattice chains.

Jakub Krajniak; Michal Banaszak

2014-10-15T23:59:59.000Z

394

Operational Experiences Tuning the ATF2 Final Focus Optics Towards Obtaining a 37nm Electron Beam IP Spot Size  

SciTech Connect (OSTI)

The primary aim of the ATF2 research accelerator is to test a scaled version of the final focus optics planned for use in next-generation linear lepton colliders. ATF2 consists of a 1.3 GeV linac, damping ring providing low-emittance electron beams (< 12pm in the vertical plane), extraction line and final focus optics. The design details of the final focus optics and implementation at ATF2 are presented elsewhere. The ATF2 accelerator is currently being commissioned, with a staged approach to achieving the design IP spot size. It is expected that as we implement more demanding optics and reduce the vertical beta function at the IP, the tuning becomes more difficult and takes longer. We present here a description of the implementation of the tuning procedures and describe operational experiences and performances.

White, Glen; /SLAC; Seryi, Andrei; /SLAC; Woodley, Mark; /SLAC; Bai, Sha; /Beijing, Inst. High Energy Phys.; Bambade, Philip; /Orsay, LAL; Renier, Yves; /Orsay, LAL; Bolzon, Benoit; /Annecy, LAPP; Kamiya, Yoshio; /Tokyo U., ICEPP; Komamiya, Sachio; /Tokyo U.; Oroku, Masahiro; /Tokyo U.; Yamaguchi, Yohei; /Tokyo U.; Yamanaka, Takashi; /Tokyo U.; Kubo, Kiyoshi; /KEK, Tsukuba; Kuroda, Shigeru; /KEK, Tsukuba; Okugi, Toshiyuki; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Marin, Eduardo; /CERN

2012-07-06T23:59:59.000Z

395

Localization of VP28 on the baculovirus envelope and its immunogenicity against white spot syndrome virus in Penaeus monodon  

SciTech Connect (OSTI)

White spot syndrome virus (WSSV) is a large dsDNA virus responsible for white spot disease in shrimp and other crustaceans. VP28 is one of the major envelope proteins of WSSV and plays a crucial role in viral infection. In an effort to develop a vaccine against WSSV, we have constructed a recombinant baculovirus with an immediate early promoter 1 which expresses VP28 at an early stage of infection in insect cells. Baculovirus expressed rVP28 was able to maintain its structural and antigenic conformity as indicated by immunofluorescence assay and western blot analysis. Interestingly, our results with confocal microscopy revealed that rVP28 was able to localize on the plasma membrane of insect cells infected with recombinant baculovirus. In addition, we demonstrated with transmission electron microscopy that baculovirus successfully acquired rVP28 from the insect cell membrane via the budding process. Using this baculovirus displaying VP28 as a vaccine against WSSV, we observed a significantly higher survival rate of 86.3% and 73.5% of WSSV-infected shrimp at 3 and 15 days post vaccination respectively. Quantitative real-time PCR also indicated that the WSSV viral load in vaccinated shrimp was significantly reduced at 7 days post challenge. Furthermore, our RT-PCR and immunohistochemistry results demonstrated that the recombinant baculovirus was able to express VP28 in vivo in shrimp tissues. This study will be of considerable significance in elucidating the morphogenesis of WSSV and will pave the way for new generation vaccines against WSSV.

Syed Musthaq, S.; Madhan, Selvaraj [Animal Health Biotechnology, Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, 117604 (Singapore); Sahul Hameed, A.S. [OIE Expert, OIE Reference Laboratory for WTD, C. Abdul Hakeem College, Melvisharam 632 509 (India); Kwang, Jimmy, E-mail: kwang@tll.org.s [Animal Health Biotechnology, Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, 117604 (Singapore); Department of Microbiology, Faculty of Medicine, National University of Singapore (Singapore)

2009-09-01T23:59:59.000Z

396

A dose point kernel database using GATE Monte Carlo simulation toolkit for nuclear medicine applications: Comparison with other Monte Carlo codes  

SciTech Connect (OSTI)

Purpose: GATE is a Monte Carlo simulation toolkit based on the Geant4 package, widely used for many medical physics applications, including SPECT and PET image simulation and more recently CT image simulation and patient dosimetry. The purpose of the current study was to calculate dose point kernels (DPKs) using GATE, compare them against reference data, and finally produce a complete dataset of the total DPKs for the most commonly used radionuclides in nuclear medicine. Methods: Patient-specific absorbed dose calculations can be carried out using Monte Carlo simulations. The latest version of GATE extends its applications to Radiotherapy and Dosimetry. Comparison of the proposed method for the generation of DPKs was performed for (a) monoenergetic electron sources, with energies ranging from 10 keV to 10 MeV, (b) beta emitting isotopes, e.g., {sup 177}Lu, {sup 90}Y, and {sup 32}P, and (c) gamma emitting isotopes, e.g., {sup 111}In, {sup 131}I, {sup 125}I, and {sup 99m}Tc. Point isotropic sources were simulated at the center of a sphere phantom, and the absorbed dose was stored in concentric spherical shells around the source. Evaluation was performed with already published studies for different Monte Carlo codes namely MCNP, EGS, FLUKA, ETRAN, GEPTS, and PENELOPE. A complete dataset of total DPKs was generated for water (equivalent to soft tissue), bone, and lung. This dataset takes into account all the major components of radiation interactions for the selected isotopes, including the absorbed dose from emitted electrons, photons, and all secondary particles generated from the electromagnetic interactions. Results: GATE comparison provided reliable results in all cases (monoenergetic electrons, beta emitting isotopes, and photon emitting isotopes). The observed differences between GATE and other codes are less than 10% and comparable to the discrepancies observed among other packages. The produced DPKs are in very good agreement with the already published data, which allowed us to produce a unique DPKs dataset using GATE. The dataset contains the total DPKs for {sup 67}Ga, {sup 68}Ga, {sup 90}Y, {sup 99m}Tc, {sup 111}In, {sup 123}I, {sup 124}I, {sup 125}I, {sup 131}I, {sup 153}Sm, {sup 177}Lu {sup 186}Re, and {sup 188}Re generated in water, bone, and lung. Conclusions: In this study, the authors have checked GATE's reliability for absorbed dose calculation when transporting different kind of particles, which indicates its robustness for dosimetry applications. A novel dataset of DPKs is provided, which can be applied in patient-specific dosimetry using analytical point kernel convolution algorithms.

Papadimitroulas, Panagiotis; Loudos, George; Nikiforidis, George C.; Kagadis, George C. [Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 265 04 (Greece) and Department of Medical Instruments Technology, Technological Educational institute of Athens, Ag. Spyridonos Street, Egaleo GR 122 10, Athens (Greece); Department of Medical Instruments Technology, Technological Educational institute of Athens, Ag. Spyridonos Street, Egaleo GR 122 10, Athens (Greece); Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 265 04 (Greece)

2012-08-15T23:59:59.000Z

397

Experimental Component Characterization, Monte-Carlo-Based Image Generation and Source Reconstruction for the Neutron Imaging System of the National Ignition Facility  

SciTech Connect (OSTI)

The Neutron Imaging System (NIS) is one of seven ignition target diagnostics under development for the National Ignition Facility. The NIS is required to record hot-spot (13-15 MeV) and downscattered (6-10 MeV) images with a resolution of 10 microns and a signal-to-noise ratio (SNR) of 10 at the 20% contour. The NIS is a valuable diagnostic since the downscattered neutrons reveal the spatial distribution of the cold fuel during an ignition attempt, providing important information in the case of a failed implosion. The present study explores the parameter space of several line-of-sight (LOS) configurations that could serve as the basis for the final design. Six commercially available organic scintillators were experimentally characterized for their light emission decay profile and neutron sensitivity. The samples showed a long lived decay component that makes direct recording of a downscattered image impossible. The two best candidates for the NIS detector material are: EJ232 (BC422) plastic fibers or capillaries filled with EJ399B. A Monte Carlo-based end-to-end model of the NIS was developed to study the imaging capabilities of several LOS configurations and verify that the recovered sources meet the design requirements. The model includes accurate neutron source distributions, aperture geometries (square pinhole, triangular wedge, mini-penumbral, annular and penumbral), their point spread functions, and a pixelated scintillator detector. The modeling results show that a useful downscattered image can be obtained by recording the primary peak and the downscattered images, and then subtracting a decayed version of the former from the latter. The difference images need to be deconvolved in order to obtain accurate source distributions. The images are processed using a frequency-space modified-regularization algorithm and low-pass filtering. The resolution and SNR of these sources are quantified by using two surrogate sources. The simulations show that all LOS configurations have a resolution of 7 microns or better. The 28 m LOS with a 7 x 7 array of 100-micron mini-penumbral apertures or 50-micron square pinholes meets the design requirements and is a very good design alternative.

Barrera, C A; Moran, M J

2007-08-21T23:59:59.000Z

398

Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds  

SciTech Connect (OSTI)

This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS). DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. The critical fusion zone sizes to ensure nugget pull-out failure mode are developed for both DP800 and TRIP800 using limit load based analytical model and micro-hardness measurements of the weld cross sections. Static weld strength tests using cross tension samples were performed on the joint populations with controlled fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied for all the weld populations using statistical data analysis tools. The results in this study show that AHSS spot welds with fusion zone size of can not produce nugget pullout mode for both the DP800 and TRIP800 materials examined. The critical fusion zone size for nugget pullout shall be derived for individual materials based on different base metal properties as well as different heat affected zone (HAZ) and weld properties resulted from different welding parameters.

Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2007-01-01T23:59:59.000Z

399

have spotted. Drug addiction can be treated and abstinence achieved, and with a programmatic approach to maintaining abstinence, the illness is ar-  

E-Print Network [OSTI]

have spotted. Drug addiction can be treated and abstinence achieved, and with a programmatic to treat a specific problem. This knowledge can assist the employee in making an informed choice from a list of ap- proved providers. If a managed care referral is made to a therapist to treat a problem

Kim, Duck O.

400

PLUS: FAT, BUT NOT SICK HOW TO SPOT QUACKERY GREEN BUSINESS MAGA ZINE OF THE GER ALD J. AND DOROTHY R.  

E-Print Network [OSTI]

PLUS: FAT, BUT NOT SICK HOW TO SPOT QUACKERY GREEN BUSINESS NUTRITION MAGA ZINE OF THE GER ALD J N G . G R O W T H . G R AT I T U D E . 32 ALUMNI NEWS S TAY I N G C O N N E C T E D 36 LAST BITE WA

Dennett, Daniel

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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401

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 38, NO. 6, JUNE 2002 665 Facet Reflectivity of a Spot-Size-Converter Integrated  

E-Print Network [OSTI]

of 7 dBm are observed at the fabricated SOA, which consists of a window length of 20 m, facet angle reflectivity, semiconductor op- tical amplifier, spot-size-converter, window. I. INTRODUCTION SEMICONDUCTOR) coating requires a quarter-wave film with a refractive index equal to the square root of the refractive

402

A comparison of automated land cover/use classification methods for a Texas bottomland hardwood system using lidar, spot-5, and ancillary data  

E-Print Network [OSTI]

decisions affecting these disappearing systems. SPOT-5 imagery from 2005 was combined with Light Detection and Ranging (LiDAR) data from 2006 and several ancillary datasets to map a portion of the bottomland hardwood system found in the Sulphur River Basin...

Vernon, Zachary Isaac

2009-05-15T23:59:59.000Z

403

Measured and Monte Carlo calculated k{sub Q} factors: Accuracy and comparison  

SciTech Connect (OSTI)

Purpose: The journal Medical Physics recently published two papers that determine beam quality conversion factors, k{sub Q}, for large sets of ion chambers. In the first paper [McEwen Med. Phys. 37, 2179-2193 (2010)], k{sub Q} was determined experimentally, while the second paper [Muir and Rogers Med. Phys. 37, 5939-5950 (2010)] provides k{sub Q} factors calculated using Monte Carlo simulations. This work investigates a variety of additional consistency checks to verify the accuracy of the k{sub Q} factors determined in each publication and a comparison of the two data sets. Uncertainty introduced in calculated k{sub Q} factors by possible variation of W/e with beam energy is investigated further. Methods: The validity of the experimental set of k{sub Q} factors relies on the accuracy of the NE2571 reference chamber measurements to which k{sub Q} factors for all other ion chambers are correlated. The stability of NE2571 absorbed dose to water calibration coefficients is determined and comparison to other experimental k{sub Q} factors is analyzed. Reliability of Monte Carlo calculated k{sub Q} factors is assessed through comparison to other publications that provide Monte Carlo calculations of k{sub Q} as well as an analysis of the sleeve effect, the effect of cavity length and self-consistencies between graphite-walled Farmer-chambers. Comparison between the two data sets is given in terms of the percent difference between the k{sub Q} factors presented in both publications. Results: Monitoring of the absorbed dose calibration coefficients for the NE2571 chambers over a period of more than 15 yrs exhibit consistency at a level better than 0.1%. Agreement of the NE2571 k{sub Q} factors with a quadratic fit to all other experimental data from standards labs for the same chamber is observed within 0.3%. Monte Carlo calculated k{sub Q} factors are in good agreement with most other Monte Carlo calculated k{sub Q} factors. Expected results are observed for the sleeve effect and the effect of cavity length on k{sub Q}. The mean percent differences between experimental and Monte Carlo calculated k{sub Q} factors are -0.08, -0.07, and -0.23% for the Elekta 6, 10, and 25 MV nominal beam energies, respectively. An upper limit on the variation of W/e in photon beams from cobalt-60 to 25 MV is determined as 0.4% with 95% confidence. The combined uncertainty on Monte Carlo calculated k{sub Q} factors is reassessed and amounts to between 0.40 and 0.49% depending on the wall material of the chamber. Conclusions: Excellent agreement (mean percent difference of only 0.13% for the entire data set) between experimental and calculated k{sub Q} factors is observed. For some chambers, k{sub Q} is measured for only one chamber of each type--the level of agreement observed in this study would suggest that for those chambers the measured k{sub Q} values are generally representative of the chamber type.

Muir, B. R.; McEwen, M. R.; Rogers, D. W. O. [Ottawa Medical Physics Institute (OMPI), Ottawa Carleton Institute for Physics, Carleton University Campus, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada); Institute for National Measurement Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada); Ottawa Medical Physics Institute (OMPI), Ottawa Carleton Institute for Physics, Carleton University Campus, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada)

2011-08-15T23:59:59.000Z

404

Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds under Lap Shear Loading Conditions  

SciTech Connect (OSTI)

This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS) under lap shear loading condition. DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. Static weld strength tests using lap shear samples were performed on the joint populations with various fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied for all the weld populations using statistical data analysis tools. The results in this study show that AHSS spot welds with conventionally required fusion zone size of can not produce nugget pullout mode for both the DP800 and TRIP800 welds under lap shear loading. Moreover, failure mode has strong influence on weld peak load and energy absorption for all the DP800 welds and the TRIP800 small welds: welds failed in pullout mode have statistically higher strength and energy absorption than those failed in interfacial fracture mode. For TRIP800 welds above the critical fusion zone level, the influence of weld failure modes on peak load and energy absorption diminishes. Scatter plots of peak load and energy absorption versus weld fusion zone size were then constructed, and the results indicate that fusion zone size is the most critical factor in weld quality in terms of peak load and energy absorption for both DP800 and TRIP800 spot welds.

Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2008-06-01T23:59:59.000Z

405

Charged-Particle Thermonuclear Reaction Rates: I. Monte Carlo Method and Statistical Distributions  

E-Print Network [OSTI]

A method based on Monte Carlo techniques is presented for evaluating thermonuclear reaction rates. We begin by reviewing commonly applied procedures and point out that reaction rates that have been reported up to now in the literature have no rigorous statistical meaning. Subsequently, we associate each nuclear physics quantity entering in the calculation of reaction rates with a specific probability density function, including Gaussian, lognormal and chi-squared distributions. Based on these probability density functions the total reaction rate is randomly sampled many times until the required statistical precision is achieved. This procedure results in a median (Monte Carlo) rate which agrees under certain conditions with the commonly reported recommended "classical" rate. In addition, we present at each temperature a low rate and a high rate, corresponding to the 0.16 and 0.84 quantiles of the cumulative reaction rate distribution. These quantities are in general different from the statistically meaningless "minimum" (or "lower limit") and "maximum" (or "upper limit") reaction rates which are commonly reported. Furthermore, we approximate the output reaction rate probability density function by a lognormal distribution and present, at each temperature, the lognormal parameters miu and sigma. The values of these quantities will be crucial for future Monte Carlo nucleosynthesis studies. Our new reaction rates, appropriate for bare nuclei in the laboratory, are tabulated in the second paper of this series (Paper II). The nuclear physics input used to derive our reaction rates is presented in the third paper of this series (Paper III). In the fourth paper of this series (Paper IV) we compare our new reaction rates to previous results.

Richard Longland; Christian Iliadis; Art Champagne; Joe Newton; Claudio Ugalde; Alain Coc; Ryan Fitzgerald

2010-04-23T23:59:59.000Z

406

A VAX version of the coupled Monte Carlo transport codes HETC and MORSE-CGA  

SciTech Connect (OSTI)

The three-dimensional Monte Carlo transport codes, HETC and MORSE-CGA, are distributed by the Radiation Shielding Information Center at Oak Ridge National Laboratory. These codes, written for IBM-3033 computers, have been installed on the Environmental Measurements Laboratory's VAX/11-750 computer for operation in a coupled mode to study the transport of neutrons over the energy range from thermal to several GeV. This report is a guide to their use on the VAX/11-750 computer. 26 refs., 6 figs., 14 tabs.

Sanna, R.S.

1990-12-01T23:59:59.000Z

407

Probability of initiation and extinction in the Mercury Monte Carlo code  

SciTech Connect (OSTI)

A Monte Carlo method for computing the probability of initiation has previously been implemented in Mercury. Recently, a new method based on the probability of extinction has been implemented as well. The methods have similarities from counting progeny to cycling in time, but they also have differences such as population control and statistical uncertainty reporting. The two methods agree very well for several test problems. Since each method has advantages and disadvantages, we currently recommend that both methods are used to compute the probability of criticality. (authors)

McKinley, M. S.; Brantley, P. S. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94551 (United States)

2013-07-01T23:59:59.000Z

408

Estimation of 6 groups of effective delayed neutron fraction based on continuous energy Monte Carlo method  

SciTech Connect (OSTI)

New method is proposed to estimate effective fraction of delayed neutrons radiated from precursors categorized into 6 groups of decay constant. Instead of adjoint flux {Phi}*, an expected number of fission neutrons in next generations, M, is applied as a weight function [1]. Introduction of M enables us to calculate the fraction based on continuous energy Monte Carlo method. For the calculation of the fraction, an algorithm is established and implemented into the MCNP-5 code. The method is verified using reactor period data obtained in reactivity measurements. (authors)

Nauchi, Y.; Kameyama, T. [Central Research Inst., Electric Power Industry, 2-11-1 Iwado-Kita, Komae-shi, Tokyo 201-8511 (Japan)

2006-07-01T23:59:59.000Z

409

Monte Carlo Generators for Studies of the 3D Structure of the Nucleon  

SciTech Connect (OSTI)

Extraction of transverse momentum and space distributions of partons from measurements of spin and azimuthal asymmetries requires development of a self consistent analysis framework, accounting for evolution effects, and allowing control of systematic uncertainties due to variations of input parameters and models. Development of realistic Monte-Carlo generators, accounting for TMD evolution effects, spin-orbit and quark-gluon correlations will be crucial for future studies of quark-gluon dynamics in general and 3D structure of the nucleon in particular.

Avagyan, Harut A. [JLAB

2015-01-01T23:59:59.000Z

410

Finite-temperature quantum Monte Carlo study of the one-dimensional polarized Fermi gas  

SciTech Connect (OSTI)

Quantum Monte Carlo (QMC) techniques are used to provide an approximation-free investigation of the phases of the one-dimensional attractive Hubbard Hamiltonian in the presence of population imbalance. The temperature at which the ''Fulde-Ferrell-Larkin-Ovchinnikov'' (FFLO) phase is destroyed by thermal fluctuations is determined as a function of the polarization. It is shown that the presence of a confining potential does not dramatically alter the FFLO regime and that recent experiments on trapped atomic gases likely lie just within the stable temperature range.

Wolak, M. J. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Rousseau, V. G. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Miniatura, C. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, F-06560 Valbonne (France); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Gremaud, B. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Scalettar, R. T. [Physics Department, University of California, Davis, California 95616 (United States); Batrouni, G. G. [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, F-06560 Valbonne (France)

2010-07-15T23:59:59.000Z

411

Tomographic image of prompt gamma ray from boron neutron capture therapy: A Monte Carlo simulation study  

SciTech Connect (OSTI)

Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography image from boron neutron capture therapy using Monte Carlo simulation. Prompt gamma ray (478?keV) was used to reconstruct image with ordered subsets expectation maximization method. From analysis of receiver operating characteristic curve, area under curve values of three boron regions were 0.738, 0.623, and 0.817. The differences between length of centers of two boron regions and distance of maximum count points were 0.3?cm, 1.6?cm, and 1.4?cm.

Yoon, Do-Kun; Jung, Joo-Young; Suk Suh, Tae, E-mail: suhsanta@catholic.ac.kr [Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 505 (Korea, Republic of); Jo Hong, Key [Molecular Imaging Program at Stanford (MIPS), Department of Radiology, Stanford University, 300 Pasteur Drive, Stanford, California 94305 (United States)

2014-02-24T23:59:59.000Z

412

Thermonuclear reaction rate of $^{18}$Ne($?$,$p$)$^{21}$Na from Monte-Carlo calculations  

E-Print Network [OSTI]

The $^{18}$Ne($\\alpha$,$p$)$^{21}$Na reaction impacts the break-out from the hot CNO-cycles to the $rp$-process in type I X-ray bursts. We present a revised thermonuclear reaction rate, which is based on the latest experimental data. The new rate is derived from Monte-Carlo calculations, taking into account the uncertainties of all nuclear physics input quantities. In addition, we present the reaction rate uncertainty and probability density versus temperature. Our results are also consistent with estimates obtained using different indirect approaches.

P. Mohr; R. Longland; C. Iliadis

2014-12-14T23:59:59.000Z

413

Thermonuclear reaction rate of $^{18}$Ne($\\alpha$,$p$)$^{21}$Na from Monte-Carlo calculations  

E-Print Network [OSTI]

The $^{18}$Ne($\\alpha$,$p$)$^{21}$Na reaction impacts the break-out from the hot CNO-cycles to the $rp$-process in type I X-ray bursts. We present a revised thermonuclear reaction rate, which is based on the latest experimental data. The new rate is derived from Monte-Carlo calculations, taking into account the uncertainties of all nuclear physics input quantities. In addition, we present the reaction rate uncertainty and probability density versus temperature. Our results are also consistent with estimates obtained using different indirect approaches.

Mohr, P; Iliadis, C

2014-01-01T23:59:59.000Z

414

Monte-Carlo study of the phase transition in the AA-stacked bilayer graphene  

E-Print Network [OSTI]

Tight-binding model of the AA-stacked bilayer graphene with screened electron-electron interactions has been studied using the Hybrid Monte Carlo simulations on the original double-layer hexagonal lattice. Instantaneous screened Coulomb potential is taken into account using Hubbard-Stratonovich transformation. G-type antiferromagnetic ordering has been studied and the phase transition with spontaneous generation of the mass gap has been observed. Dependence of the antiferromagnetic condensate on the on-site electron-electron interaction is examined.

Nikolaev, A A

2014-01-01T23:59:59.000Z

415

SIM-RIBRAS: A Monte-Carlo simulation package for RIBRAS system  

SciTech Connect (OSTI)

SIM-RIBRAS is a Root-based Monte-Carlo simulation tool designed to help RIBRAS users on experience planning and experimental setup enhancing and caracterization. It is divided into two main programs: CineRIBRAS, aiming beam kinematics, and SolFocus, aiming beam optics. SIM-RIBRAS replaces other methods and programs used in the past, providing more complete and accurate results and requiring much less manual labour. Moreover, the user can easily make modifications in the codes, adequating it for specific requirements of an experiment.

Leistenschneider, E.; Lepine-Szily, A.; Lichtenthaeler, R. [Departamento de Fisica Nuclear, Instituto de Fisica, Universidade de Sao Paulo (Brazil)

2013-05-06T23:59:59.000Z

416

Monte-Carlo study of the phase transition in the AA-stacked bilayer graphene  

E-Print Network [OSTI]

Tight-binding model of the AA-stacked bilayer graphene with screened electron-electron interactions has been studied using the Hybrid Monte Carlo simulations on the original double-layer hexagonal lattice. Instantaneous screened Coulomb potential is taken into account using Hubbard-Stratonovich transformation. G-type antiferromagnetic ordering has been studied and the phase transition with spontaneous generation of the mass gap has been observed. Dependence of the antiferromagnetic condensate on the on-site electron-electron interaction is examined.

A. A. Nikolaev; M. V. Ulybyshev

2014-12-04T23:59:59.000Z

417

Monte Carlo Fundamentals E B. BROWN and T M. S N  

Office of Scientific and Technical Information (OSTI)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartmentNationalRestart ofMeasuringInformation 9StructureContactWindFINALi MineSeisMonte

418

Improving the hot-spot pressure and demonstrating ignition hydrodynamic equivalence in cryogenic deuterium–tritium implosions on OMEGA  

SciTech Connect (OSTI)

Reaching ignition in direct-drive (DD) inertial confinement fusion implosions requires achieving central pressures in excess of 100 Gbar. The OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] is used to study the physics of implosions that are hydrodynamically equivalent to the ignition designs on the National Ignition Facility (NIF) [J. A. Paisner et al., Laser Focus World 30, 75 (1994)]. It is shown that the highest hot-spot pressures (up to 40 Gbar) are achieved in target designs with a fuel adiabat of ? ? 4, an implosion velocity of 3.8?×?10{sup 7}?cm/s, and a laser intensity of ?10{sup 15}?W/cm{sup 2}. These moderate-adiabat implosions are well understood using two-dimensional hydrocode simulations. The performance of lower-adiabat implosions is significantly degraded relative to code predictions, a common feature between DD implosions on OMEGA and indirect-drive cryogenic implosions on the NIF. Simplified theoretical models are developed to gain physical understanding of the implosion dynamics that dictate the target performance. These models indicate that degradations in the shell density and integrity (caused by hydrodynamic instabilities during the target acceleration) coupled with hydrodynamics at stagnation are the main failure mechanisms in low-adiabat designs. To demonstrate ignition hydrodynamic equivalence in cryogenic implosions on OMEGA, the target-design robustness to hydrodynamic instability growth must be improved by reducing laser-coupling losses caused by cross beam energy transfer.

Goncharov, V. N.; Sangster, T. C.; Betti, R.; Boehly, T. R.; Bonino, M. J.; Collins, T. J. B.; Craxton, R. S.; Delettrez, J. A.; Edgell, D. H.; Epstein, R.; Follett, R. K.; Forrest, C. J.; Froula, D. H.; Glebov, V. Yu.; Harding, D. R.; Henchen, R. J.; Hu, S. X.; Igumenshchev, I. V.; Janezic, R.; Kelly, J. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); and others

2014-05-15T23:59:59.000Z

419

Uranium Bioreduction Rates across Scales: Biogeochemical Hot Moments and Hot Spots during a Biostimulation Experiment at Rifle, Colorado  

SciTech Connect (OSTI)

We aim to understand the scale-dependent evolution of uranium bioreduction during a field experiment at a former uranium mill site near Rifle, Colorado. Acetate was injected to stimulate Fe-reducing bacteria (FeRB) and to immobilize aqueous U(VI) to insoluble U(IV). Bicarbonate was coinjected in half of the domain to mobilize sorbed U(VI). We used reactive transport modeling to integrate hydraulic and geochemical data and to quantify rates at the grid block (0.25 m) and experimental field scale (tens of meters). Although local rates varied by orders of magnitude in conjunction with biostimulation fronts propagating downstream, field-scale rates were dominated by those orders of magnitude higher rates at a few selected hot spots where Fe(III), U(VI), and FeRB were at their maxima in the vicinity of the injection wells. At particular locations, the hot moments with maximum rates negatively corresponded to their distance from the injection wells. Although bicarbonate injection enhanced local rates near the injection wells by a maximum of 39.4%, its effect at the field scale was limited to a maximum of 10.0%. We propose a rate-versus-measurement-length relationship (log R' = -0.63

Bao, Chen; Wu, Hongfei; Li, Li; Newcomer, Darrell R.; Long, Philip E.; Williams, Kenneth H.

2014-09-02T23:59:59.000Z

420

Monte Carlo wave packet approach to dissociative multiple ionization in diatomic molecules  

SciTech Connect (OSTI)

A detailed description of the Monte Carlo wave packet technique applied to dissociative multiple ionization of diatomic molecules in short intense laser pulses is presented. The Monte Carlo wave packet technique relies on the Born-Oppenheimer separation of electronic and nuclear dynamics and provides a consistent theoretical framework for treating simultaneously both ionization and dissociation. By simulating the detection of continuum electrons and collapsing the system onto either the neutral, singly ionized or doubly ionized states in every time step the nuclear dynamics can be solved separately for each molecular charge state. Our model circumvents the solution of a multiparticle Schroedinger equation and makes it possible to extract the kinetic energy release spectrum via the Coulomb explosion channel as well as the physical origin of the different structures in the spectrum. The computational effort is restricted and the model is applicable to any molecular system where electronic Born-Oppenheimer curves, dipole moment functions, and ionization rates as a function of nuclear coordinates can be determined.

Leth, Henriette Astrup; Madsen, Lars Bojer; Moelmer, Klaus [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2010-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
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421

Monte Carlo approach for hadron azimuthal correlations in high energy proton and nuclear collisions  

E-Print Network [OSTI]

We use a Monte Carlo approach to study hadron azimuthal angular correlations in high energy proton-proton and central nucleus-nucleus collisions at the BNL Relativistic Heavy Ion Collider (RHIC) energies at mid-rapidity. We build a hadron event generator that incorporates the production of $2\\to 2$ and $2\\to 3$ parton processes and their evolution into hadron states. For nucleus-nucleus collisions we include the effect of parton energy loss in the Quark-Gluon Plasma using a modified fragmentation function approach. In the presence of the medium, for the case when three partons are produced in the hard scattering, we analyze the Monte Carlo sample in parton and hadron momentum bins to reconstruct the angular correlations. We characterize this sample by the number of partons that are able to hadronize by fragmentation within the selected bins. In the nuclear environment the model allows hadronization by fragmentation only for partons with momentum above a threshold $p_T^{{\\tiny{thresh}}}=2.4$ GeV. We argue that...

Ayala, Alejandro; Jalilian-Marian, Jamal; Magnin, J; Tejeda-Yeomans, Maria Elena

2012-01-01T23:59:59.000Z

422

Monte Carlo approach for hadron azimuthal correlations in high energy proton and nuclear collisions  

E-Print Network [OSTI]

We use a Monte Carlo approach to study hadron azimuthal angular correlations in high energy proton-proton and central nucleus-nucleus collisions at the BNL Relativistic Heavy Ion Collider (RHIC) energies at mid-rapidity. We build a hadron event generator that incorporates the production of $2\\to 2$ and $2\\to 3$ parton processes and their evolution into hadron states. For nucleus-nucleus collisions we include the effect of parton energy loss in the Quark-Gluon Plasma using a modified fragmentation function approach. In the presence of the medium, for the case when three partons are produced in the hard scattering, we analyze the Monte Carlo sample in parton and hadron momentum bins to reconstruct the angular correlations. We characterize this sample by the number of partons that are able to hadronize by fragmentation within the selected bins. In the nuclear environment the model allows hadronization by fragmentation only for partons with momentum above a threshold $p_T^{{\\tiny{thresh}}}=2.4$ GeV. We argue that one should treat properly the effect of those partons with momentum below the threshold, since their interaction with the medium may lead to showers of low momentum hadrons along the direction of motion of the original partons as the medium becomes diluted.

Alejandro Ayala; Isabel Dominguez; Jamal Jalilian-Marian; J. Magnin; Maria Elena Tejeda-Yeomans

2012-07-31T23:59:59.000Z

423

Energy density matrix formalism for interacting quantum systems: a quantum Monte Carlo study  

SciTech Connect (OSTI)

We develop an energy density matrix that parallels the one-body reduced density matrix (1RDM) for many-body quantum systems. Just as the density matrix gives access to the number density and occupation numbers, the energy density matrix yields the energy density and orbital occupation energies. The eigenvectors of the matrix provide a natural orbital partitioning of the energy density while the eigenvalues comprise a single particle energy spectrum obeying a total energy sum rule. For mean-field systems the energy density matrix recovers the exact spectrum. When correlation becomes important, the occupation energies resemble quasiparticle energies in some respects. We explore the occupation energy spectrum for the finite 3D homogeneous electron gas in the metallic regime and an isolated oxygen atom with ground state quantum Monte Carlo techniques imple- mented in the QMCPACK simulation code. The occupation energy spectrum for the homogeneous electron gas can be described by an effective mass below the Fermi level. Above the Fermi level evanescent behavior in the occupation energies is observed in similar fashion to the occupation numbers of the 1RDM. A direct comparison with total energy differences demonstrates a quantita- tive connection between the occupation energies and electron addition and removal energies for the electron gas. For the oxygen atom, the association between the ground state occupation energies and particle addition and removal energies becomes only qualitative. The energy density matrix provides a new avenue for describing energetics with quantum Monte Carlo methods which have traditionally been limited to total energies.

Krogel, Jaron T [ORNL] [ORNL; Kim, Jeongnim [ORNL] [ORNL; Reboredo, Fernando A [ORNL] [ORNL

2014-01-01T23:59:59.000Z

424

Massively parallel Monte Carlo for many-particle simulations on GPUs  

SciTech Connect (OSTI)

Current trends in parallel processors call for the design of efficient massively parallel algorithms for scientific computing. Parallel algorithms for Monte Carlo simulations of thermodynamic ensembles of particles have received little attention because of the inherent serial nature of the statistical sampling. In this paper, we present a massively parallel method that obeys detailed balance and implement it for a system of hard disks on the GPU. We reproduce results of serial high-precision Monte Carlo runs to verify the method. This is a good test case because the hard disk equation of state over the range where the liquid transforms into the solid is particularly sensitive to small deviations away from the balance conditions. On a Tesla K20, our GPU implementation executes over one billion trial moves per second, which is 148 times faster than on a single Intel Xeon E5540 CPU core, enables 27 times better performance per dollar, and cuts energy usage by a factor of 13. With this improved performance we are able to calculate the equation of state for systems of up to one million hard disks. These large system sizes are required in order to probe the nature of the melting transition, which has been debated for the last forty years. In this paper we present the details of our computational method, and discuss the thermodynamics of hard disks separately in a companion paper.

Anderson, Joshua A.; Jankowski, Eric [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Grubb, Thomas L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Engel, Michael [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Glotzer, Sharon C., E-mail: sglotzer@umich.edu [Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

2013-12-01T23:59:59.000Z

425

Physics and Algorithm Enhancements for a Validated MCNP/X Monte Carlo Simulation Tool, Phase VII  

SciTech Connect (OSTI)

Currently the US lacks an end-to-end (i.e., source-to-detector) radiation transport simulation code with predictive capability for the broad range of DHS nuclear material detection applications. For example, gaps in the physics, along with inadequate analysis algorithms, make it difficult for Monte Carlo simulations to provide a comprehensive evaluation, design, and optimization of proposed interrogation systems. With the development and implementation of several key physics and algorithm enhancements, along with needed improvements in evaluated data and benchmark measurements, the MCNP/X Monte Carlo codes will provide designers, operators, and systems analysts with a validated tool for developing state-of-the-art active and passive detection systems. This project is currently in its seventh year (Phase VII). This presentation will review thirty enhancements that have been implemented in MCNPX over the last 3 years and were included in the 2011 release of version 2.7.0. These improvements include 12 physics enhancements, 4 source enhancements, 8 tally enhancements, and 6 other enhancements. Examples and results will be provided for each of these features. The presentation will also discuss the eight enhancements that will be migrated into MCNP6 over the upcoming year.

McKinney, Gregg W [Los Alamos National Laboratory

2012-07-17T23:59:59.000Z

426

Monte Carlo methods and their analysis for Coulomb collisions in multicomponent plasmas  

SciTech Connect (OSTI)

Highlights: •A general approach to Monte Carlo methods for multicomponent plasmas is proposed. •We show numerical tests for the two-component (electrons and ions) case. •An optimal choice of parameters for speeding up the computations is discussed. •A rigorous estimate of the error of approximation is proved. -- Abstract: A general approach to Monte Carlo methods for Coulomb collisions is proposed. Its key idea is an approximation of Landau–Fokker–Planck equations by Boltzmann equations of quasi-Maxwellian kind. It means that the total collision frequency for the corresponding Boltzmann equation does not depend on the velocities. This allows to make the simulation process very simple since the collision pairs can be chosen arbitrarily, without restriction. It is shown that this approach includes the well-known methods of Takizuka and Abe (1977) [12] and Nanbu (1997) as particular cases, and generalizes the approach of Bobylev and Nanbu (2000). The numerical scheme of this paper is simpler than the schemes by Takizuka and Abe [12] and by Nanbu. We derive it for the general case of multicomponent plasmas and show some numerical tests for the two-component (electrons and ions) case. An optimal choice of parameters for speeding up the computations is also discussed. It is also proved that the order of approximation is not worse than O(?(?)), where ? is a parameter of approximation being equivalent to the time step ?t in earlier methods. A similar estimate is obtained for the methods of Takizuka and Abe and Nanbu.

Bobylev, A.V., E-mail: alexander.bobylev@kau.se [Department of Mathematics, Karlstad University, SE-65188 Karlstad (Sweden); Potapenko, I.F., E-mail: firena@yandex.ru [Keldysh Institute for Applied Mathematics, RAS, 125047 Moscow (Russian Federation)

2013-08-01T23:59:59.000Z

427

An Evaluation of Monte Carlo Simulations of Neutron Multiplicity Measurements of Plutonium Metal  

SciTech Connect (OSTI)

In January 2009, Sandia National Laboratories conducted neutron multiplicity measurements of a polyethylene-reflected plutonium metal sphere. Over the past 3 years, those experiments have been collaboratively analyzed using Monte Carlo simulations conducted by University of Michigan (UM), Los Alamos National Laboratory (LANL), Sandia National Laboratories (SNL), and North Carolina State University (NCSU). Monte Carlo simulations of the experiments consistently overpredict the mean and variance of the measured neutron multiplicity distribution. This paper presents a sensitivity study conducted to evaluate the potential sources of the observed errors. MCNPX-PoliMi simulations of plutonium neutron multiplicity measurements exhibited systematic over-prediction of the neutron multiplicity distribution. The over-prediction tended to increase with increasing multiplication. MCNPX-PoliMi had previously been validated against only very low multiplication benchmarks. We conducted sensitivity studies to try to identify the cause(s) of the simulation errors; we eliminated the potential causes we identified, except for Pu-239 {bar {nu}}. A very small change (-1.1%) in the Pu-239 {bar {nu}} dramatically improved the accuracy of the MCNPX-PoliMi simulation for all 6 measurements. This observation is consistent with the trend observed in the bias exhibited by the MCNPX-PoliMi simulations: a very small error in {bar {nu}} is 'magnified' by increasing multiplication. We applied a scalar adjustment to Pu-239 {bar {nu}} (independent of neutron energy); an adjustment that depends on energy is probably more appropriate.

Mattingly, John [North Carolina State University; Miller, Eric [University of Michigan; Solomon, Clell J. Jr. [Los Alamos National Laboratory; Dennis, Ben [University of Michigan; Meldrum, Amy [University of Michigan; Clarke, Shaun [University of Michigan; Pozzi, Sara [University of Michigan

2012-06-21T23:59:59.000Z

428

MONTE CARLO SIMULATION MODEL OF ENERGETIC PROTON TRANSPORT THROUGH SELF-GENERATED ALFVEN WAVES  

SciTech Connect (OSTI)

A new Monte Carlo simulation model for the transport of energetic protons through self-generated Alfven waves is presented. The key point of the model is that, unlike the previous ones, it employs the full form (i.e., includes the dependence on the pitch-angle cosine) of the resonance condition governing the scattering of particles off Alfven waves-the process that approximates the wave-particle interactions in the framework of quasilinear theory. This allows us to model the wave-particle interactions in weak turbulence more adequately, in particular, to implement anisotropic particle scattering instead of isotropic scattering, which the previous Monte Carlo models were based on. The developed model is applied to study the transport of flare-accelerated protons in an open magnetic flux tube. Simulation results for the transport of monoenergetic protons through the spectrum of Alfven waves reveal that the anisotropic scattering leads to spatially more distributed wave growth than isotropic scattering. This result can have important implications for diffusive shock acceleration, e.g., affect the scattering mean free path of the accelerated particles in and the size of the foreshock region.

Afanasiev, A.; Vainio, R., E-mail: alexandr.afanasiev@helsinki.fi [Department of Physics, University of Helsinki (Finland)

2013-08-15T23:59:59.000Z

429

A Deterministic-Monte Carlo Hybrid Method for Time-Dependent Neutron Transport Problems  

SciTech Connect (OSTI)

A new deterministic-Monte Carlo hybrid solution technique is derived for the time-dependent transport equation. This new approach is based on dividing the time domain into a number of coarse intervals and expanding the transport solution in a series of polynomials within each interval. The solutions within each interval can be represented in terms of arbitrary source terms by using precomputed response functions. In the current work, the time-dependent response function computations are performed using the Monte Carlo method, while the global time-step march is performed deterministically. This work extends previous work by coupling the time-dependent expansions to space- and angle-dependent expansions to fully characterize the 1D transport response/solution. More generally, this approach represents and incremental extension of the steady-state coarse-mesh transport method that is based on global-local decompositions of large neutron transport problems. An example of a homogeneous slab is discussed as an example of the new developments.

Justin Pounders; Farzad Rahnema

2001-10-01T23:59:59.000Z

430

GUINEVERE experiment: Kinetic analysis of some reactivity measurement methods by deterministic and Monte Carlo codes  

SciTech Connect (OSTI)

The GUINEVERE experiment (Generation of Uninterrupted Intense Neutrons at the lead Venus Reactor) is an experimental program in support of the ADS technology presently carried out at SCK-CEN in Mol (Belgium). In the experiment a modified lay-out of the original thermal VENUS critical facility is coupled to an accelerator, built by the French body CNRS in Grenoble, working in both continuous and pulsed mode and delivering 14 MeV neutrons by bombardment of deuterons on a tritium-target. The modified lay-out of the facility consists of a fast subcritical core made of 30% U-235 enriched metallic Uranium in a lead matrix. Several off-line and on-line reactivity measurement techniques will be investigated during the experimental campaign. This report is focused on the simulation by deterministic (ERANOS French code) and Monte Carlo (MCNPX US code) calculations of three reactivity measurement techniques, Slope ({alpha}-fitting), Area-ratio and Source-jerk, applied to a GUINEVERE subcritical configuration (namely SC1). The inferred reactivity, in dollar units, by the Area-ratio method shows an overall agreement between the two deterministic and Monte Carlo computational approaches, whereas the MCNPX Source-jerk results are affected by large uncertainties and allow only partial conclusions about the comparison. Finally, no particular spatial dependence of the results is observed in the case of the GUINEVERE SC1 subcritical configuration. (authors)

Bianchini, G.; Burgio, N.; Carta, M. [ENEA C.R. CASACCIA, via Anguillarese, 301, 00123 S. Maria di Galeria Roma (Italy); Peluso, V. [ENEA C.R. BOLOGNA, Via Martiri di Monte Sole, 4, 40129 Bologna (Italy); Fabrizio, V.; Ricci, L. [Univ. of Rome La Sapienza, C/o ENEA C.R. CASACCIA, via Anguillarese, 301, 00123 S. Maria di Galeria Roma (Italy)

2012-07-01T23:59:59.000Z

431

A Monte Carlo Study of Multiplicity Fluctuations in Pb-Pb Collisions at LHC Energies  

E-Print Network [OSTI]

With large volumes of data available from LHC, it has become possible to study the multiplicity distributions for the various possible behaviours of the multiparticle production in collisions of relativistic heavy ion collisions, where a system of dense and hot partons has been created. In this context it is important and interesting as well to check how well the Monte Carlo generators can describe the properties or the behaviour of multiparticle production processes. One such possible behaviour is the self-similarity in the particle production, which can be studied with the intermittency studies and further with chaoticity/erraticity, in the heavy ion collisions. We analyse the behaviour of erraticity index in central Pb-Pb collisions at centre of mass energy of 2.76 TeV per nucleon using the AMPT monte carlo event generator, following the recent proposal by R.C. Hwa and C.B. Yang, concerning the local multiplicity fluctuation study as a signature of critical hadronization in heavy-ion collisions. We report ...

Gupta, Ramni

2015-01-01T23:59:59.000Z

432

CoRoT's view on variable B8/9 stars: spots versus pulsations: Evidence for differential rotation in HD 174648  

E-Print Network [OSTI]

Context. There exist few variability studies of stars in the region in the Hertzsprung-Russell diagram between the A and B-star pulsational instability strips. With the aid of the high precision continuous measurements of the CoRoT space satellite, low amplitudes are more easily detected, making a study of this neglected region worthwhile. Aims. We collected a small sample of B stars observed by CoRoT to determine the origin of the different types of variability observed. Methods. We combine literature photometry and spectroscopy to measure the fundamental parameters of the stars in the sample, and compare asteroseismic modelling of the light curves with (differentially rotating) spotted star models. Results. We found strong evidence for the existence of spots and differential rotation in HD 174648, and formulated hypotheses for their origin. We show that the distinction between pulsations and rotational modulation is difficult to make solely based on the light curve, especially in slowly rotating stars.

Degroote, P; Samadi, R; Aerts, C; Kurtz, D W; Noels, A; Miglio, A; Montalban, J; Bloemen, S; Baglin, A; Baudin, F; Catala, C; Michel, E; Auvergne, M

2011-01-01T23:59:59.000Z

433

Plasmon Mapping in Metallic Nanostructures and its Application to Single Molecule Surface Enhanced Raman Scattering: Imaging Electromagnetic Hot-Spots and Analyte Location  

SciTech Connect (OSTI)

A major component of this proposal is to elucidate the connection between optical and electron excitation of plasmon modes in metallic nanostructures. These accomplishments are reported: developed a routine protocol for obtaining spatially resolved, low energy EELS spectra, and resonance Rayleigh scattering spectra from the same nanostructures.; correlated optical scattering spectra and plasmon maps obtained using STEM/EELS.; and imaged electromagnetic hot spots responsible for single-molecule surface-enhanced Raman scattering (SMSERS).

Camden, Jon P

2013-07-16T23:59:59.000Z

434

Using standard calibrated geometries to characterize a coaxial high purity germanium gamma detector for Monte Carlo simulations  

SciTech Connect (OSTI)

A detector model optimization procedure based on matching Monte Carlo simulations with measurements for two experimentally calibrated sample geometries which are frequently used in radioactivity measurement laboratories results in relative agreement within 5% between simulated and measured efficiencies for a high purity germanium detector. The optimization procedure indicated that the increase in dead layer thickness is largely responsible for a detector efficiency decrease in time. The optimized detector model allows Monte Carlo efficiency calibration for all other samples of which the geometry and bulk composition is known. The presented method is a competitive and economic alternative to more elaborate detector scanning methods and results in a comparable accuracy.

Graaf, E. R. van der, E-mail: vandergraaf@kvi.nl; Dendooven, P.; Brandenburg, S. [KVI-Center for Advanced Radiation Technology (KVI-CART), University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands)

2014-06-15T23:59:59.000Z

435

The topological susceptibility from grand canonical simulations in the interacting instanton liquid model: strongly associating fluids and biased Monte Carlo  

E-Print Network [OSTI]

This is the second in a series of papers that investigates the topological susceptibility in the interacting instanton liquid model (IILM) at finite temperature, and deals with the technical issues relating to the Monte Carlo simulations. The IILM reduces field theory to a molecular dynamics description, and for `physical' quark masses the system behaves like a strongly associating fluid. We will argue that this is a generic feature for very light Dirac quark in a non-trivial background, described in the semi-classical approach. To get rid of unnecessary complications, we will present the ideas of biased Monte Carlo, and implement the transition probabilities, for a toy model.

Olivier Wantz

2010-01-14T23:59:59.000Z

436

Study on in situ calibration for neutron flux monitor in the Large Helical Device based on Monte Carlo calculations  

SciTech Connect (OSTI)

Neutron monitoring is important to manage safety of fusion experiment facilities because neutrons are generated in fusion reactions. Monte Carlo simulations play an important role in evaluating the influence of neutron scattering from various structures and correcting differences between deuterium plasma experiments and in situ calibration experiments. We evaluated these influences based on differences between the both experiments at Large Helical Device using Monte Carlo simulation code MCNP5. A difference between the both experiments in absolute detection efficiency of the fission chamber between O-ports is estimated to be the biggest of all monitors. We additionally evaluated correction coefficients for some neutron monitors.

Nakano, Y., E-mail: nakano.yuuji@c.mbox.nagoya-u.ac.jp; Yamazaki, A.; Watanabe, K.; Uritani, A. [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Ogawa, K.; Isobe, M. [National Institute for Fusion Science, Toki-city, GIFU 509-5292 (Japan)

2014-11-15T23:59:59.000Z

437

Quality of Life and Toxicity From Passively Scattered and Spot-Scanning Proton Beam Therapy for Localized Prostate Cancer  

SciTech Connect (OSTI)

Purpose: To report quality of life (QOL)/toxicity in men treated with proton beam therapy for localized prostate cancer and to compare outcomes between passively scattered proton therapy (PSPT) and spot-scanning proton therapy (SSPT). Methods and Materials: Men with localized prostate cancer enrolled on a prospective QOL protocol with a minimum of 2 years' follow-up were reviewed. Comparative groups were defined by technique (PSPT vs SSPT). Patients completed Expanded Prostate Cancer Index Composite questionnaires at baseline and every 3-6 months after proton beam therapy. Clinically meaningful differences in QOL were defined as ?0.5 × baseline standard deviation. The cumulative incidence of modified Radiation Therapy Oncology Group grade ?2 gastrointestinal (GI) or genitourinary (GU) toxicity and argon plasma coagulation were determined by the Kaplan-Meier method. Results: A total of 226 men received PSPT, and 65 received SSPT. Both PSPT and SSPT resulted in statistically significant changes in sexual, urinary, and bowel Expanded Prostate Cancer Index Composite summary scores. Only bowel summary, function, and bother resulted in clinically meaningful decrements beyond treatment completion. The decrement in bowel QOL persisted through 24-month follow-up. Cumulative grade ?2 GU and GI toxicity at 24 months were 13.4% and 9.6%, respectively. There was 1 grade 3 GI toxicity (PSPT group) and no other grade ?3 GI or GU toxicity. Argon plasma coagulation application was infrequent (PSPT 4.4% vs SSPT 1.5%; P=.21). No statistically significant differences were appreciated between PSPT and SSPT regarding toxicity or QOL. Conclusion: Both PSPT and SSPT confer low rates of grade ?2 GI or GU toxicity, with preservation of meaningful sexual and urinary QOL at 24 months. A modest, yet clinically meaningful, decrement in bowel QOL was seen throughout follow-up. No toxicity or QOL differences between PSPT and SSPT were identified. Long-term comparative results in a larger patient cohort are warranted.

Pugh, Thomas J. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Munsell, Mark F. [Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Choi, Seungtaek; Nguyen, Quyhn Nhu; Mathai, Benson [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhu, X. Ron; Sahoo, Narayan; Gillin, Michael; Johnson, Jennifer L.; Amos, Richard A. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dong, Lei [Scripps Proton Therapy Center, San Diego, California (United States); Mahmood, Usama; Kuban, Deborah A.; Frank, Steven J.; Hoffman, Karen E.; McGuire, Sean E. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lee, Andrew K., E-mail: aklee@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

2013-12-01T23:59:59.000Z

438

Multi-Scale Multi-physics Methods Development for the Calculation of Hot-Spots in the NGNP  

SciTech Connect (OSTI)

Radioactive gaseous fission products are released out of the fuel element at a significantly higher rate when the fuel temperature exceeds 1600°C in high-temperature gas-cooled reactors (HTGRs). Therefore, it is of paramount importance to accurately predict the peak fuel temperature during all operational and design-basis accident conditions. The current methods used to predict the peak fuel temperature in HTGRs, such as the Next-Generation Nuclear Plant (NGNP), estimate the average fuel temperature in a computational mesh modeling hundreds of fuel pebbles or a fuel assembly in a pebble-bed reactor (PBR) or prismatic block type reactor (PMR), respectively. Experiments conducted in operating HTGRs indicate considerable uncertainty in the current methods and correlations used to predict actual temperatures. The objective of this project is to improve the accuracy in the prediction of local "hot" spots by developing multi-scale, multi- physics methods and implementing them within the framework of established codes used for NGNP analysis. The multi-scale approach which this project will implement begins with defining suitable scales for a physical and mathematical model and then deriving and applying the appropriate boundary conditions between scales. The macro scale is the greatest length that describes the entire reactor, whereas the meso scale models only a fuel block in a prismatic reactor and ten to hundreds of pebbles in a pebble bed reactor. The smallest scale is the micro scale--the level of a fuel kernel of the pebble in a PBR and fuel compact in a PMR--which needs to be resolved in order to calculate the peak temperature in a fuel kernel.

Downar, Thomas; Seker, Volkan

2013-04-30T23:59:59.000Z

439

The giant star of the symbiotic system YY Her: Rotation, Tidal wave, Solar-type cycle and Spots  

E-Print Network [OSTI]

We analyze the historical light curve of the symbiotic star YY Her, from 1890 up to December 2005. A secular declining trend is detected, at a rate of ~.01 magn in 1000 d, suggesting that the system could belong to the sub-class of symbiotic novae. Several outburst events are superposed on this slow decline. Three independent periodicities are identified in the light curve. A quasi-periodicity of 4650.7 d is detected for the outburst occurrence. We suggest that it is a signature of a solar-type magnetic dynamo cycle in the giant component. A period of 593.2 d modulates the quiescent light curve and it is identified as the binary period of the system. During outburst events the system shows a stable periodic oscillation of 551.4 d. We suggest that it is the rotation period of the giant.The secondary minima detected at some epochs of quiescence are probably due to dark spots on the surface of the rotating giant. The difference between the frequencies of these two last periods is the frequency of a tidal wave in the outer layers of the giant. A period which is a beat between the magnetic cycle and the tidal wave period is also apparent in the light curve. YY Her is a third symbiotic system exhibiting these cycles in their light curve, suggesting that a magnetic dynamo process is prevalent in the giant components of symbiotic stars, playing an important role in the outburst mechanism of some of these systems.

Liliana Formiggini; Elia M. Leibowitz

2006-09-17T23:59:59.000Z

440

Surface tension of an electrolyteair interface: a Monte Carlo study This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-Print Network [OSTI]

Surface tension of an electrolyte­air interface: a Monte Carlo study This article has been 24 (2012) 284115 (5pp) doi:10.1088/0953-8984/24/28/284115 Surface tension of an electrolyte for calculating the surface tension of an electrolyte­air interface using Monte Carlo (MC) simulations

Levin, Yan

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Directions for in-gel tryptic digestions of coomassie-stained 1D Bands and 2D Spots. NOTE: Although nearly any SDS-PAGE system can be utilized upstream of an LC-MS analysis, the DPCF  

E-Print Network [OSTI]

Directions for in-gel tryptic digestions of coomassie-stained 1D Bands and 2D Spots. NOTE: Although digestion should be done in a BSC or laminar flow hood. 2. Wear nitrile (not latex) gloves. 3. Wear a lab (for a single 2D gel spot, use 25-30 µL of 10 ng/µL trypsin). 9. Digest overnight for 16-18 hours at 37

Richardson, David

442

Directions for in-gel tryptic digestions of coomassie-stained 1D Bands and 2D Spots. NOTE: Although nearly any SDS-PAGE system can be utilized upstream of an LC-MS analysis, the DPCF  

E-Print Network [OSTI]

Directions for in-gel tryptic digestions of coomassie-stained 1D Bands and 2D Spots. NOTE: Although digestion should be done in a BSC or laminar flow hood. 2. Wear nitrile (not latex) gloves. 3. Wear a lab gel spot, use 25-30 µL of 10 ng/µL trypsin). 5. Digest overnight for 16-18 hours at 37°C. 6. Following

Richardson, David

443

Converting Boundary Representation Solid Models to Half-Space Representation Models for Monte Carlo Analysis  

SciTech Connect (OSTI)

Solid modeling computer software systems provide for the design of three-dimensional solid models used in the design and analysis of physical components. The current state-of-the-art in solid modeling representation uses a boundary representation format in which geometry and topology are used to form three-dimensional boundaries of the solid. The geometry representation used in these systems is cubic B-spline curves and surfaces--a network of cubic B-spline functions in three-dimensional Cartesian coordinate space. Many Monte Carlo codes, however, use a geometry representation in which geometry units are specified by intersections and unions of half-spaces. This paper describes an algorithm for converting from a boundary representation to a half-space representation.

Davis JE, Eddy MJ, Sutton TM, Altomari TJ

2007-03-01T23:59:59.000Z

444

Resonating Valence Bond Quantum Monte Carlo: Application to the ozone molecule  

E-Print Network [OSTI]

We study the potential energy surface of the ozone molecule by means of Quantum Monte Carlo simulations based on the resonating valence bond concept. The trial wave function consists of an antisymmetrized geminal power arranged in a single-determinant that is multiplied by a Jastrow correlation factor. Whereas the determinantal part incorporates static correlation effects, the augmented real-space correlation factor accounts for the dynamics electron correlation. The accuracy of this approach is demonstrated by computing the potential energy surface for the ozone molecule in three vibrational states: symmetric, asymmetric and scissoring. We find that the employed wave function provides a detailed description of rather strongly-correlated multi-reference systems, which is in quantitative agreement with experiment.

Azadi, Sam; Kühne, Thomas D

2015-01-01T23:59:59.000Z

445

MaGe - a Geant4-based Monte Carlo framework for low-background experiments  

E-Print Network [OSTI]

A Monte Carlo framework, MaGe, has been developed based on the Geant4 simulation toolkit. Its purpose is to simulate physics processes in low-energy and low-background radiation detectors, specifically for the Majorana and Gerda $^{76}$Ge neutrinoless double-beta decay experiments. This jointly-developed tool is also used to verify the simulation of physics processes relevant to other low-background experiments in Geant4. The MaGe framework contains simulations of prototype experiments and test stands, and is easily extended to incorporate new geometries and configurations while still using the same verified physics processes, tunings, and code framework. This reduces duplication of efforts and improves the robustness of and confidence in the simulation output.

Yuen-Dat Chan; Jason A. Detwiler; Reyco Henning; Victor M. Gehman; Rob A. Johnson; David V. Jordan; Kareem Kazkaz; Markus Knapp; Kevin Kroninger; Daniel Lenz; Jing Liu; Xiang Liu; Michael G. Marino; Akbar Mokhtarani; Luciano Pandola; Alexis G. Schubert; Claudia Tomei

2008-02-06T23:59:59.000Z

446

Validation of GEANT4 Monte Carlo Models with a Highly Granular Scintillator-Steel Hadron Calorimeter  

E-Print Network [OSTI]

Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8GeV to 100GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated.

C. Adloff; J. Blaha; J. -J. Blaising; C. Drancourt; A. Espargiličre; R. Gaglione; N. Geffroy; Y. Karyotakis; J. Prast; G. Vouters; K. Francis; J. Repond; J. Schlereth; J. Smith; L. Xia; E. Baldolemar; J. Li; S. T. Park; M. Sosebee; A. P. White; J. Yu; T. Buanes; G. Eigen; Y. Mikami; N. K. Watson; G. Mavromanolakis; M. A. Thomson; D. R. Ward; W. Yan; D. Benchekroun; A. Hoummada; Y. Khoulaki; J. Apostolakis; A. Dotti; G. Folger; V. Ivantchenko; V. Uzhinskiy; M. Benyamna; C. Cârloganu; F. Fehr; P. Gay; S. Manen; L. Royer; G. C. Blazey; A. Dyshkant; J. G. R. Lima; V. Zutshi; J. -Y. Hostachy; L. Morin; U. Cornett; D. David; G. Falley; K. Gadow; P. Göttlicher; C. Günter; B. Hermberg; S. Karstensen; F. Krivan; A. -I. Lucaci-Timoce; S. Lu; B. Lutz; S. Morozov; V. Morgunov; M. Reinecke; F. Sefkow; P. Smirnov; M. Terwort; A. Vargas-Trevino; N. Feege; E. Garutti; I. Marchesinik; M. Ramilli; P. Eckert; T. Harion; A. Kaplan; H. -Ch. Schultz-Coulon; W. Shen; R. Stamen; B. Bilki; E. Norbeck; Y. Onel; G. W. Wilson; K. Kawagoe; P. D. Dauncey; A. -M. Magnan; V. Bartsch; M. Wing; F. Salvatore; E. Calvo Alamillo; M. -C. Fouz; J. Puerta-Pelayo; B. Bobchenko; M. Chadeeva; M. Danilov; A. Epifantsev; O. Markin; R. Mizuk; E. Novikov; V. Popov; V. Rusinov; E. Tarkovsky; N. Kirikova; V. Kozlov; P. Smirnov; Y. Soloviev; P. Buzhan; A. Ilyin; V. Kantserov; V. Kaplin; A. Karakash; E. Popova; V. Tikhomirov; C. Kiesling; K. Seidel; F. Simon; C. Soldner; M. Szalay; M. Tesar; L. Weuste; M. S. Amjad; J. Bonis; S. Callier; S. Conforti di Lorenzo; P. Cornebise; Ph. Doublet; F. Dulucq; J. Fleury; T. Frisson; N. van der Kolk; H. Li; G. Martin-Chassard; F. Richard; Ch. de la Taille; R. Pöschl; L. Raux; J. Rouëné; N. Seguin-Moreau; M. Anduze; V. Boudry; J-C. Brient; D. Jeans; P. Mora de Freitas; G. Musat; M. Reinhard; M. Ruan; H. Videau; B. Bulanek; J. Zacek; J. Cvach; P. Gallus; M. Havranek; M. Janata; J. Kvasnicka; D. Lednicky; M. Marcisovsky; I. Polak; J. Popule; L. Tomasek; M. Tomasek; P. Ruzicka; P. Sicho; J. Smolik; V. Vrba; J. Zalesak; B. Belhorma; H. Ghazlane; T. Takeshita; S. Uozumi; M. Götze; O. Hartbrich; J. Sauer; S. Weber; C. Zeitnitz

2014-06-15T23:59:59.000Z

447

Uncertainties associated with the use of the KENO Monte Carlo criticality codes  

SciTech Connect (OSTI)

The KENO multi-group Monte Carlo criticality codes have earned the reputation of being efficient, user friendly tools especially suited for the analysis of situations commonly encountered in the storage and transportation of fissile materials. Throughout their twenty years of service, a continuing effort has been made to maintain and improve these codes to meet the needs of the nuclear criticality safety community. Foremost among these needs is the knowledge of how to utilize the results safely and effectively. Therefore it is important that code users be aware of uncertainties that may affect their results. These uncertainties originate from approximations in the problem data, methods used to process cross sections, and assumptions, limitations and approximations within the criticality computer code itself. 6 refs., 8 figs., 1 tab.

Landers, N.F.; Petrie, L.M. (Oak Ridge National Lab., TN (USA))

1989-01-01T23:59:59.000Z

448

Monte-Carlo study of quasiparticle dispersion relation in monolayer graphene  

E-Print Network [OSTI]

The density of electronic one-particle states in monolayer graphene is studied by performing the Hybrid Monte-Carlo simulations of the tight-binding model for electrons on the pi orbitals of carbon atoms which make up the graphene lattice. Density of states is approximated as a derivative of the number of particles over the chemical potential at sufficiently small temperature. Simulations are performed in the partially quenched approximation, in which virtual particles and holes have zero chemical potential. It is found that the Van Hove singularity becomes much sharper than in the free tight-binding model. Simulation results also suggest that the Fermi velocity increases with interaction strength up to the transition to the phase with spontaneously broken chiral symmetry.

P. V. Buividovich

2013-01-07T23:59:59.000Z

449

From hypernuclei to the Inner Core of Neutron Stars: A Quantum Monte Carlo Study  

E-Print Network [OSTI]

Auxiliary Field Diffusion Monte Carlo (AFDMC) calculations have been employed to revise the interaction between $\\Lambda$-hyperons and nucleons in hypernuclei. The scheme used to describe the interaction, inspired by the phenomenological Argonne-Urbana forces, is the $\\Lambda N+\\Lambda NN$ potential firstly introduced by Bodmer, Usmani et al.. Within this framework, we performed calculations on light and medium mass hypernuclei in order to assess the extent of the repulsive contribution of the three-body part. By tuning this contribution in order to reproduce the $\\Lambda$ separation energy in $^5_\\Lambda$He and $^{17}_{~\\Lambda}$O, experimental findings are reproduced over a wide range of masses. Calculations have then been extended to $\\Lambda$-neutron matter in order to derive an analogous of the symmetry energy to be used in determining the equation of state of matter in the typical conditions found in the inner core of neutron stars.

Diego Lonardoni; Francesco Pederiva; Stefano Gandolfi

2014-08-19T23:59:59.000Z

450

The Auxiliary Field Diffusion Monte Carlo Method for Nuclear Physics and Nuclear Astrophysics  

E-Print Network [OSTI]

In this thesis, I discuss the use of the Auxiliary Field Diffusion Monte Carlo method to compute the ground state of nuclear Hamiltonians, and I show several applications to interesting problems both in nuclear physics and in nuclear astrophysics. In particular, the AFDMC algorithm is applied to the study of several nuclear systems, finite, and infinite matter. Results about the ground state of nuclei ($^4$He, $^8$He, $^{16}$O and $^{40}$Ca), neutron drops (with 8 and 20 neutrons) and neutron rich-nuclei (isotopes of oxygen and calcium) are discussed, and the equation of state of nuclear and neutron matter are calculated and compared with other many-body calculations. The $^1S_0$ superfluid phase of neutron matter in the low-density regime was also studied.

Stefano Gandolfi

2007-12-09T23:59:59.000Z

451

Auxiliary-field quantum Monte Carlo method for strongly paired fermions  

SciTech Connect (OSTI)

We solve the zero-temperature unitary Fermi gas problem by incorporating a BCS importance function into the auxiliary-field quantum Monte Carlo method. We demonstrate that this method does not suffer from a sign problem and that it increases the efficiency of standard techniques by many orders of magnitude for strongly paired fermions. We calculate the ground-state energies exactly for unpolarized systems with up to 66 particles on lattices of up to 27{sup 3} sites, obtaining an accurate result for the universal parameter {xi}. We also obtain results for interactions with different effective ranges and find that the energy is consistent with a universal linear dependence on the product of the Fermi momentum and the effective range. This method will have many applications in superfluid cold atom systems and in both electronic and nuclear structures where pairing is important.

Carlson, J.; Gandolfi, Stefano [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Schmidt, Kevin E. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Zhang, Shiwei [Department of Physics, College of William and Mary, Williamsburg, Virginia 23187 (United States)

2011-12-15T23:59:59.000Z

452

Ab-initio molecular dynamics simulation of liquid water by Quantum Monte Carlo  

E-Print Network [OSTI]

Despite liquid water is ubiquitous in chemical reactions at roots of life and climate on earth, the prediction of its properties by high-level ab initio molecular dynamics simulations still represents a formidable task for quantum chemistry. In this article we present a room temperature simulation of liquid water based on the potential energy surface obtained by a many-body wave function through quantum Monte Carlo (QMC) methods. The simulated properties are in excellent agreement with recent neutron scattering and X-ray experiments, particularly concerning the position of the oxygen-oxygen peak in the radial distribution function, at variance of previous Density Functional Theory attempts. Given the excellent performances of QMC on large scale supercomputers, this work opens new perspectives for predictive and reliable ab-initio simulations of complex chemical systems.

Andrea Zen; Ye Luo; Guglielmo Mazzola; Leonardo Guidoni; Sandro Sorella

2014-12-09T23:59:59.000Z

453

Report on International Collaboration Involving the FE Heater and HG-A Tests at Mont Terri  

SciTech Connect (OSTI)

Nuclear waste programs outside of the US have focused on different host rock types for geological disposal of high-level radioactive waste. Several countries, including France, Switzerland, Belgium, and Japan are exploring the possibility of waste disposal in shale and other clay-rich rock that fall within the general classification of argillaceous rock. This rock type is also of interest for the US program because the US has extensive sedimentary basins containing large deposits of argillaceous rock. LBNL, as part of the DOE-NE Used Fuel Disposition Campaign, is collaborating on some of the underground research laboratory (URL) activities at the Mont Terri URL near Saint-Ursanne, Switzerland. The Mont Terri project, which began in 1995, has developed a URL at a depth of about 300 m in a stiff clay formation called the Opalinus Clay. Our current collaboration efforts include two test modeling activities for the FE heater test and the HG-A leak-off test. This report documents results concerning our current modeling of these field tests. The overall objectives of these activities include an improved understanding of and advanced relevant modeling capabilities for EDZ evolution in clay repositories and the associated coupled processes, and to develop a technical basis for the maximum allowable temperature for a clay repository. The R&D activities documented in this report are part of the work package of natural system evaluation and tool development that directly supports the following Used Fuel Disposition Campaign (UFDC) objectives: ? Develop a fundamental understanding of disposal-system performance in a range of environments for potential wastes that could arise from future nuclear-fuel-cycle alternatives through theory, simulation, testing, and experimentation. ? Develop a computational modeling capability for the performance of storage and disposal options for a range of fuel-cycle alternatives, evolving from generic models to more robust models of performance assessment. For the purpose of validating modeling capabilities for thermal-hydro-mechanical (THM) processes, we developed a suite of simulation models for the planned full-scale FE Experiment to be conducted in the Mont Terri URL, including a full three-dimensional model that will be used for direct comparison to experimental data once available. We performed for the first time a THM analysis involving the Barcelona Basic Model (BBM) in a full three-dimensional field setting for modeling the geomechanical behavior of the buffer material and its interaction with the argillaceous host rock. We have simulated a well defined benchmark that will be used for codeto- code verification against modeling results from other international modeling teams. The analysis highlights the complex coupled geomechanical behavior in the buffer and its interaction with the surrounding rock and the importance of a well characterized buffer material in terms of THM properties. A new geomechanical fracture-damage model, TOUGH-RBSN, was applied to investigate damage behavior in the ongoing HG-A test at Mont Terri URL. Two model modifications have been implemented so that the Rigid-Body-Spring-Network (RBSN) model can be used for analysis of fracturing around the HG-A microtunnel. These modifications are (1) a methodology to compute fracture generation under compressive stress conditions and (2) a method to represent anisotropic elastic and strength properties. The method for computing fracture generation under compressive load produces results that roughly follow trends expected for homogeneous and layered systems. Anisotropic properties for the bulk rock were represented in the RBSN model using layered heterogeneity and gave bulk material responses in line with expectations. These model improvements were implemented for an initial model of fracture damage at the HG-A test. While the HG-A test model results show some similarities with the test observations, differences between the model results and observations remain.

Houseworth, Jim; Rutqvist, Jonny; Asahina, Daisuke; Chen, Fei; Vilarrasa, Victor; Liu, Hui-Hai; Birkholzer, Jens

2013-11-06T23:59:59.000Z

454

A portable, parallel, object-oriented Monte Carlo neutron transport code in C++  

SciTech Connect (OSTI)

We have developed a multi-group Monte Carlo neutron transport code using C++ and the Parallel Object-Oriented Methods and Applications (POOMA) class library. This transport code, called MC++, currently computes k and {alpha}-eigenvalues and is portable to and runs parallel on a wide variety of platforms, including MPPs, clustered SMPs, and individual workstations. It contains appropriate classes and abstractions for particle transport and, through the use of POOMA, for portable parallelism. Current capabilities of MC++ are discussed, along with physics and performance results on a variety of hardware, including all Accelerated Strategic Computing Initiative (ASCI) hardware. Current parallel performance indicates the ability to compute {alpha}-eigenvalues in seconds to minutes rather than hours to days. Future plans and the implementation of a general transport physics framework are also discussed.

Lee, S.R.; Cummings, J.C. [Los Alamos National Lab., NM (United States); Nolen, S.D. [Texas A and M Univ., College Station, TX (United States)]|[Los Alamos National Lab., NM (United States)

1997-05-01T23:59:59.000Z

455

A Monte-Carlo method for ex-core neutron response  

SciTech Connect (OSTI)

A Monte Carlo neutron transport kernel capability primarily for ex-core neutron response is described. The capability consists of the generation of a set of response kernels, which represent the neutron transport from the core to a specific ex-core volume. This is accomplished by tagging individual neutron histories from their initial source sites and tracking them throughout the problem geometry, tallying those that interact in the geometric regions of interest. These transport kernels can subsequently be combined with any number of core power distributions to determine detector response for a variety of reactor Thus, the transport kernels are analogous to an integrated adjoint response. Examples of pressure vessel response and ex-core neutron detector response are provided to illustrate the method.

Gamino, R.G.; Ward, J.T.; Hughes, J.C. [Lockheed Martin Corp., Schenectady, NY (United States)

1997-10-01T23:59:59.000Z

456

MC++: A parallel, portable, Monte Carlo neutron transport code in C++  

SciTech Connect (OSTI)

MC++ is an implicit multi-group Monte Carlo neutron transport code written in C++ and based on the Parallel Object-Oriented Methods and Applications (POOMA) class library. MC++ runs in parallel on and is portable to a wide variety of platforms, including MPPs, SMPs, and clusters of UNIX workstations. MC++ is being developed to provide transport capabilities to the Accelerated Strategic Computing Initiative (ASCI). It is also intended to form the basis of the first transport physics framework (TPF), which is a C++ class library containing appropriate abstractions, objects, and methods for the particle transport problem. The transport problem is briefly described, as well as the current status and algorithms in MC++ for solving the transport equation. The alpha version of the POOMA class library is also discussed, along with the implementation of the transport solution algorithms using POOMA. Finally, a simple test problem is defined and performance and physics results from this problem are discussed on a variety of platforms.

Lee, S.R.; Cummings, J.C. [Los Alamos National Lab., NM (United States); Nolen, S.D. [Texas A & M Univ., College Station, TX (United States)

1997-03-01T23:59:59.000Z

457

Kinetic Monte Carlo Simulation of Electrodeposition using the Embedded-Atom Method  

E-Print Network [OSTI]

A kinetic Monte Carlo (KMC) method is presented to simulate the electrodeposition of a metal on a single crystal surface of the same metal under galvanostatic conditions. This method utilizes the multi-body embedded-atom method (EAM) potential to characterize the interactions of metal atoms and adatoms. The KMC method accounts for deposition and surface diffusion processes including hopping, atom exchange and step-edge atom exchange. Steady-state deposition configurations obtained using the KMC method are validated by comparison with the structures obtained through the use of molecular dynamics (MD) simulations to relax KMC constraints. The results of this work support the use of the proposed KMC method to simulate electrodeposition processes at length (microns) and time (seconds) scales that are not feasible using other methods.

Treeratanaphitak, Tanyakarn; Abukhdeir, Nasser Mohieddin

2013-01-01T23:59:59.000Z

458

Ferroelectric domain formation in discotic liquid crystals : Monte Carlo study on the influence of boundary conditions  

E-Print Network [OSTI]

The realization of a spontaneous macroscopic ferroelectric order in fluids of anisotropic mesogens is a topic of both fundamental and technological interest. Recently, we demonstrated that a system of dipolar achiral disklike ellipsoids can exhibit long-searched ferroelectric liquid crystalline phases of dipolar origin. In the present work, extensive off-lattice Monte Carlo simulations are used to investigate the phase behavior of the system under the influences of the electrostatic boundary conditions that restrict any global polarization. We find that the system develops strongly ferroelectric slablike domains periodically arranged in an antiferroelectric fashion. Exploring the phase behavior at different dipole strengths, we find existence of the ferroelectric nematic and ferroelectric columnar order inside the domains. For higher dipole strengths, a biaxial phase is also obtained with a similar periodic array of ferroelectric slabs of antiparallel polarizations. We have studied the depolarizing effects by...

Bose, Tushar Kanti

2015-01-01T23:59:59.000Z

459

Monte Carlo procedure for protein folding in lattice model. Conformational rigidity  

E-Print Network [OSTI]

A rigourous Monte Carlo method for protein folding simulation on lattice model is introduced. We show that a parameter which can be seen as the rigidity of the conformations has to be introduced in order to satisfy the detailed balance condition. Its properties are discussed and its role during the folding process is elucidated. This method is applied on small chains on two-dimensional lattice. A Bortz-Kalos-Lebowitz type algorithm which allows to study the kinetic of the chains at very low temperature is implemented in the presented method. We show that the coefficients of the Arrhenius law are in good agreement with the value of the main potential barrier of the system.

Olivier Collet

1999-07-19T23:59:59.000Z

460

Validation of the Monte Carlo Criticality Program KENO V. a for highly-enriched uranium systems  

SciTech Connect (OSTI)

A series of calculations based on critical experiments have been performed using the KENO V.a Monte Carlo Criticality Program for the purpose of validating KENO V.a for use in evaluating Y-12 Plant criticality problems. The experiments were reflected and unreflected systems of single units and arrays containing highly enriched uranium metal or uranium compounds. Various geometrical shapes were used in the experiments. The SCALE control module CSAS25 with the 27-group ENDF/B-4 cross-section library was used to perform the calculations. Some of the experiments were also calculated using the 16-group Hansen-Roach Library. Results are presented in a series of tables and discussed. Results show that the criteria established for the safe application of the KENO IV program may also be used for KENO V.a results.

Knight, J.R.

1984-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "mont belvieu spot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Reversible jump Markov chain Monte Carlo computation and Bayesian model determination  

E-Print Network [OSTI]

Markov chain Monte Carlo methods for Bayesian computation have until recently been restricted to problems where the joint distribution of all variables has a density with respect to some xed standard underlying measure. They have therefore not been available for application to Bayesian model determination, where the dimensionality of the parameter vector is typically not xed. This article proposes a new framework for the construction of reversible Markov chain samplers that jump between parameter subspaces of di ering dimensionality, which is exible and entirely constructive. It should therefore have wide applicability in model determination problems. The methodology is illustrated with applications to multiple change-point analysis in one and two dimensions, and toaBayesian comparison of binomial experiments.

Peter J. Green

1995-01-01T23:59:59.000Z

462

Finite-Temperature Pairing Gap of a Unitary Fermi Gas by Quantum Monte Carlo Calculations  

SciTech Connect (OSTI)

We calculate the one-body temperature Green's (Matsubara) function of the unitary Fermi gas via quantum Monte Carlo, and extract the spectral weight function A(p,omega) using the methods of maximum entropy and singular value decomposition. From A(p,omega) we determine the quasiparticle spectrum, which can be accurately parametrized by three functions of temperature: an effective mass m*, a mean-field potential U, and a gap DELTA. Below the critical temperature T{sub c}=0.15epsilon{sub F} the results for m*, U, and DELTA can be accurately reproduced using an independent quasiparticle model. We find evidence of a pseudogap in the fermionic excitation spectrum for temperatures up to T*{approx_equal}0.20{epsilon}{sub F}>T{sub c}.

Magierski, Piotr; Wlazlowski, Gabriel [Faculty of Physics, Warsaw University of Technology, ulica Koszykowa 75, 00-662 Warsaw (Poland); Bulgac, Aurel; Drut, Joaquin E. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States)

2009-11-20T23:59:59.000Z

463

Quantum Monte Carlo study of dilute neutron matter at finite temperatures  

SciTech Connect (OSTI)

We report results of fully nonperturbative, path integral Monte Carlo calculations for dilute neutron matter. The neutron-neutron interaction in the s channel is parameterized by the scattering length and the effective range. We calculate the energy and the chemical potential as a function of temperature at density {rho}=0.003 fm{sup -3}. The critical temperature T{sub c} for the superfluid-normal phase transition is estimated from the finite size scaling of the condensate fraction. At low temperatures we extract the spectral weight function A(p,{omega}) from the imaginary time propagator using the methods of maximum entropy and singular value decomposition. We determine the quasiparticle spectrum, which can be accurately parameterized by three parameters: an effective mass m{sup *}, a mean-field potential U, and a gap {Delta}. Large values of {Delta}/T{sub c} indicate that the system is not a BCS-type superfluid at low temperatures.

Wlazlowski, Gabriel; Magierski, Piotr [Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, PL-00-662 Warsaw (Poland)

2011-01-15T23:59:59.000Z

464

Goal-oriented sensitivity analysis for lattice kinetic Monte Carlo simulations  

SciTech Connect (OSTI)

In this paper we propose a new class of coupling methods for the sensitivity analysis of high dimensional stochastic systems and in particular for lattice Kinetic Monte Carlo (KMC). Sensitivity analysis for stochastic systems is typically based on approximating continuous derivatives with respect to model parameters by the mean value of samples from a finite difference scheme. Instead of using independent samples the proposed algorithm reduces the variance of the estimator by developing a strongly correlated-“coupled”- stochastic process for both the perturbed and unperturbed stochastic processes, defined in a common state space. The novelty of our construction is that the new coupled process depends on the targeted observables, e.g., coverage, Hamiltonian, spatial correlations, surface roughness, etc., hence we refer to the proposed method as goal-oriented sensitivity analysis. In particular, the rates of the coupled Continuous Time Markov Chain are obtained as solutions to a goal-oriented optimization problem, depending on the observable of interest, by considering the minimization functional of the corresponding variance. We show that this functional can be used as a diagnostic tool for the design and evaluation of different classes of couplings. Furthermore, the resulting KMC sensitivity algorithm has an easy implementation that is based on the Bortz–Kalos–Lebowitz algorithm's philosophy, where events are divided in classes depending on level sets of the observable of interest. Finally, we demonstrate in several examples including adsorption, desorption, and diffusion Kinetic Monte Carlo that for the same confidence interval and observable, the proposed goal-oriented algorithm can be two orders of magnitude faster than existing coupling algorithms for spatial KMC such as the Common Random Number approach. We also provide a complete implementation of the proposed sensitivity analysis algorithms, including various spatial KMC examples, in a supplementary MATLAB source code.

Arampatzis, Georgios, E-mail: garab@math.uoc.gr [Department of Applied Mathematics, University of Crete (Greece) [Department of Applied Mathematics, University of Crete (Greece); Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Katsoulakis, Markos A., E-mail: markos@math.umass.edu [Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

2014-03-28T23:59:59.000Z

465

Development of a randomized 3D cell model for Monte Carlo microdosimetry simulations  

SciTech Connect (OSTI)

Purpose: The objective of the current work was to develop an algorithm for growing a macroscopic tumor volume from individual randomized quasi-realistic cells. The major physical and chemical components of the cell need to be modeled. It is intended to import the tumor volume into GEANT4 (and potentially other Monte Carlo packages) to simulate ionization events within the cell regions. Methods: A MATLAB Copyright-Sign code was developed to produce a tumor coordinate system consisting of individual ellipsoidal cells randomized in their spatial coordinates, sizes, and rotations. An eigenvalue method using a mathematical equation to represent individual cells was used to detect overlapping cells. GEANT4 code was then developed to import the coordinate system into GEANT4 and populate it with individual cells of varying sizes and composed of the membrane, cytoplasm, reticulum, nucleus, and nucleolus. Each region is composed of chemically realistic materials. Results: The in-house developed MATLAB Copyright-Sign code was able to grow semi-realistic cell distributions ({approx}2 Multiplication-Sign 10{sup 8} cells in 1 cm{sup 3}) in under 36 h. The cell distribution can be used in any number of Monte Carlo particle tracking toolkits including GEANT4, which has been demonstrated in this work. Conclusions: Using the cell distribution and GEANT4, the authors were able to simulate ionization events in the individual cell components resulting from 80 keV gamma radiation (the code is applicable to other particles and a wide range of energies). This virtual microdosimetry tool will allow for a more complete picture of cell damage to be developed.

Douglass, Michael; Bezak, Eva; Penfold, Scott [School of Chemistry and Physics, University of Adelaide, North Terrace, Adelaide 5005, South Australia (Australia) and Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide 5000, South Australia (Australia)

2012-06-15T23:59:59.000Z

466

Implementation of the probability table method in a continuous-energy Monte Carlo code system  

SciTech Connect (OSTI)

RACER is a particle-transport Monte Carlo code that utilizes a continuous-energy treatment for neutrons and neutron cross section data. Until recently, neutron cross sections in the unresolved resonance range (URR) have been treated in RACER using smooth, dilute-average representations. This paper describes how RACER has been modified to use probability tables to treat cross sections in the URR, and the computer codes that have been developed to compute the tables from the unresolved resonance parameters contained in ENDF/B data files. A companion paper presents results of Monte Carlo calculations that demonstrate the effect of the use of probability tables versus the use of dilute-average cross sections for the URR. The next section provides a brief review of the probability table method as implemented in the RACER system. The production of the probability tables for use by RACER takes place in two steps. The first step is the generation of probability tables from the nuclear parameters contained in the ENDF/B data files. This step, and the code written to perform it, are described in Section 3. The tables produced are at energy points determined by the ENDF/B parameters and/or accuracy considerations. The tables actually used in the RACER calculations are obtained in the second step from those produced in the first. These tables are generated at energy points specific to the RACER calculation. Section 4 describes this step and the code written to implement it, as well as modifications made to RACER to enable it to use the tables. Finally, some results and conclusions are presented in Section 5.

Sutton, T.M.; Brown, F.B. [Lockheed Martin Corp., Schenectady, NY (United States)

1998-10-01T23:59:59.000Z

467

Quantitative study of fluctuation effects by fast lattice Monte Carlo simulations: Compression of grafted homopolymers  

SciTech Connect (OSTI)

Using fast lattice Monte Carlo (FLMC) simulations [Q. Wang, Soft Matter 5, 4564 (2009)] and the corresponding lattice self-consistent field (LSCF) calculations, we studied a model system of grafted homopolymers, in both the brush and mushroom regimes, in an explicit solvent compressed by an impenetrable surface. Direct comparisons between FLMC and LSCF results, both of which are based on the same Hamiltonian (thus without any parameter-fitting between them), unambiguously and quantitatively reveal the fluctuations/correlations neglected by the latter. We studied both the structure (including the canonical-ensemble averages of the height and the mean-square end-to-end distances of grafted polymers) and thermodynamics (including the ensemble-averaged reduced energy density and the related internal energy per chain, the differences in the Helmholtz free energy and entropy per chain from the uncompressed state, and the pressure due to compression) of the system. In particular, we generalized the method for calculating pressure in lattice Monte Carlo simulations proposed by Dickman [J. Chem. Phys. 87, 2246 (1987)], and combined it with the Wang-Landau–Optimized Ensemble sampling [S. Trebst, D. A. Huse, and M. Troyer, Phys. Rev. E 70, 046701 (2004)] to efficiently and accurately calculate the free energy difference and the pressure due to compression. While we mainly examined the effects of the degree of compression, the distance between the nearest-neighbor grafting points, the reduced number of chains grafted at each grafting point, and the system fluctuations/correlations in an athermal solvent, the ?-solvent is also considered in some cases.

Zhang, Pengfei; Wang, Qiang, E-mail: q.wang@colostate.edu [Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, Colorado 80523-1370 (United States)] [Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, Colorado 80523-1370 (United States)

2014-01-28T23:59:59.000Z

468

Monte Carlo Simulations of the Dissolution of Borosilicate Glasses in Near-Equilibrium Conditions  

SciTech Connect (OSTI)

Monte Carlo simulations were performed to investigate the mechanisms of glass dissolution as equilibrium conditions are approached in both static and flow-through conditions. The glasses studied are borosilicate glasses in the compositional range (80 x)% SiO2 (10 + x / 2)% B2O3 (10 + x / 2)% Na2O, where 5 < x < 30%. In static conditions, dissolution/condensation reactions lead to the formation, for all compositions studied, of a blocking layer composed of polymerized Si sites with principally 4 connections to nearest Si sites. This layer forms atop the altered glass layer and shows similar composition and density for all glass compositions considered. In flow-through conditions, three main dissolution regimes are observed: at high flow rates, the dissolving glass exhibits a thin alteration layer and congruent dissolution; at low flow rates, a blocking layer is formed as in static conditions but the simulations show that water can occasionally break through the blocking layer causing the corrosion process to resume; and, at intermediate flow rates, the glasses dissolve incongruently with an increasingly deepening altered layer. The simulation results suggest that, in geological disposal environments, small perturbations or slow flows could be enough to prevent the formation of a permanent blocking layer. Finally, a comparison between predictions of the linear rate law and the Monte Carlo simulation results indicates that, in flow-through conditions, the linear rate law is applicable at high flow rates and deviations from the linear rate law occur under low flow rates (e.g., at near-saturated conditions with respect to amorphous silica). This effect is associated with the complex dynamics of Si dissolution/condensation processes at the glass water interface.

Kerisit, Sebastien [Pacific Northwest National Laboratory (PNNL); Pierce, Eric M [ORNL

2012-01-01T23:59:59.000Z

469

On-the-fly generation of differential resonance scattering probability distribution functions for Monte Carlo codes  

SciTech Connect (OSTI)

Current Monte Carlo codes use one of three models to model neutron scattering in the epithermal energy range: (1) the asymptotic scattering model, (2) the free gas scattering model, or (3) the S({alpha},{beta}) model, depending on the neutron energy and the specific Monte Carlo code. The free gas scattering model assumes the scattering cross section is constant over the neutron energy range, which is usually a good approximation for light nuclei, but not for heavy nuclei where the scattering cross section may have several resonances in the epithermal region. Several researchers in the field have shown that using the free gas scattering model in the vicinity of the resonances in the lower epithermal range can under-predict resonance absorption due to the up-scattering phenomenon. Existing methods all involve performing the collision analysis in the center-of-mass frame, followed by a conversion back to the laboratory frame. In this paper, we will present a new sampling methodology that (1) accounts for the energy-dependent scattering cross sections in the collision analysis and (2) acts in the laboratory frame, avoiding the conversion to the center-of-mass frame. The energy dependence of the scattering cross section was modeled with even-ordered polynomials to approximate the scattering cross section in Blackshaw's equations for the moments of the differential scattering PDFs. These moments were used to sample the outgoing neutron speed and angle in the laboratory frame on-the-fly during the random walk of the neutron. Results for criticality studies on fuel pin and fuel assembly calculations using these methods showed very close comparison to results using the reference Doppler-broadened rejection correction (DBRC) scheme. (authors)

Sunny, E. E.; Martin, W. R. [University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor MI 48109 (United States)

2013-07-01T23:59:59.000Z

470

Audio Spots | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone byDearTechnical Information AtomsAu10-: isomerism

471

Calculation of Nonlinear Thermoelectric Coefficients of InAs1xSbx Using Monte Carlo Method  

E-Print Network [OSTI]

and increase the cooling power density when a lightly doped thermoelectric material is under a large electrical with local nonequi- librium charge distribution. InAs1Ă?xSbx is a favorable thermoelectric materialCalculation of Nonlinear Thermoelectric Coefficients of InAs1Ă?xSbx Using Monte Carlo Method RAMIN

472

The influence of fluid flow through granitic crust: a thermo-tectonic study in and on Mont Blanc  

E-Print Network [OSTI]

The influence of fluid flow through granitic crust: a thermo-tectonic study in and on Mont Blanc Tim Dempster, Cristina Persano and Zoe Shipton *Tim.Dempster@ges.gla.ac.uk Granitic and gneissose within a evolving mountain zone, the metasomatic influence of fluids in granite gneiss and the resulting

Glasgow, University of

473

Monte Carlo Simulation-based Sensitivity Analysis of the Model of a Thermal-Hydraulic Passive System  

E-Print Network [OSTI]

1 Monte Carlo Simulation-based Sensitivity Analysis of the Model of a Thermal-Hydraulic Passive, and for this reason are expected to improve the safety of nuclear power plants. However, uncertainties are present Engineering and System Safety 107 (2012) 90-106" DOI : 10.1016/j.ress.2011.08.006 #12;2 power plants because

Paris-Sud XI, Université de

474

Nitrate dynamics in the soil and unconfined aquifer in arid groundwater coupled ecosystems of the Monte desert, Argentina  

E-Print Network [OSTI]

of the Monte desert, Argentina J. N. Aranibar,1,2 P. E. Villagra,1,3 M. L. Gomez,1 E. Jobbágy,4 M. Quiroga,1 R desert, Argentina, J. Geophys. Res., 116, G04015, doi:10.1029/2010JG001618. 1. Introduction [2] Drylands desert, Argentina, shallow groundwater is exploited by deep rooted trees, increasing primary productivity

Nacional de San Luis, Universidad

475

September 1, 2001 / Vol. 26, No. 17 / OPTICS LETTERS 1335 Perturbation Monte Carlo methods to solve inverse photon  

E-Print Network [OSTI]

September 1, 2001 / Vol. 26, No. 17 / OPTICS LETTERS 1335 Perturbation Monte Carlo methods to solve with respect to perturbations in background tissue optical properties. We then feed this derivative information to a nonlinear optimization algorithm to determine the optical properties of the tissue heterogeneity under

Boas, David

476

ATLAS-Experiment Abbildung 48: Monte-Carlo-Simulation eines tt-Ereignisses in einem Layout fur den Inne-  

E-Print Network [OSTI]

ATLAS-Experiment Abbildung 48: Monte-Carlo-Simulation eines t¯t-Ereignisses in einem Layout f¨ur den Inne- ren Detektor des ATLAS-Experiments mit vier Lagen von Silizium-Pixeldetektoren und f¨unf Lagen von Silizium-Streifendetektoren. 82 #12;ATLAS-Experiment ATLAS-Experiment Gruppenleiter: M

477

Inclusions fluides et isotopes du soufre du gisement CuAu de Valea Morii (monts Apuseni, Roumanie) : un  

E-Print Network [OSTI]

ore deposit (Apuseni mountains, Romania): telescoping between porphyry and low-sulfidation epithermal Morii Cu­Au ore deposit (Apuseni mountains, Romania) is characterised by a spatial association; Romania; epithermal; porphyry copper; deposit; fluids; telescoping Mots-clé: monts Apuseni; Roumanie

Boyer, Edmond

478

TXSAMC (transport cross sections from applied Monte Carlo): a new tool for generating shielded multigroup cross sections  

E-Print Network [OSTI]

links three external codes together to create these libraries. The code creates an MCNP (Monte Carlo N-Particle) model of the reactor and calculates the zoneaveraged scalar flux in various tally regions and a core-averaged scalar flux tallied by energy...

Hiatt, Matthew Torgerson

2009-06-02T23:59:59.000Z

479

PHYSICAL REVIEW B 83, 245414 (2011) Monte Carlo study of the honeycomb structure of anthraquinone molecules on Cu(111)  

E-Print Network [OSTI]

PHYSICAL REVIEW B 83, 245414 (2011) Monte Carlo study of the honeycomb structure of anthraquinone model, we demonstrate a mechanism for the spontaneous formation of honeycomb structure of anthraquinone­13 Pawin et al.14 observed the spontaneous formation of honeycomb structures of anthraquinone (AQ

Einstein, Theodore L.

480

Monte Carlo Simulations of Small Sulfuric Acid-Water Clusters S. M. Kathmann,* and B. N. Hale,*  

E-Print Network [OSTI]

-to-liquid nucleation1-5 to acid rain formation6-8 and ozone depletion mechanisms.9-11 Doyle's early work2 predictedMonte Carlo Simulations of Small Sulfuric Acid-Water Clusters S. M. Kathmann,* and B. N. Hale§,* En Form: August 7, 2001 Effective atom-atom potentials are developed for binary sulfuric acid

Hale, Barbara N.

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481

Quantum Monte Carlo Study of the Optical and Diffusive Properties of theVacancy Defect in Diamond  

E-Print Network [OSTI]

associated with radiation damage. It is also very interesting scientifically, with a wide variety of physicalQuantum Monte Carlo Study of the Optical and Diffusive Properties of theVacancy Defect in Diamond]. The best-known optical transition, GR1 at 1.673 eV [5], long associated with the neutral vacancy, cannot

Kent, Paul

482

Development of a device for the measurement of biological tissue optical properties using the single Monte Carlo method  

E-Print Network [OSTI]

A honeycomb probe was designed to measure the optical properties of biological tissues using single Monte Carlo method. The ongoing project is intended to be a multi-wavelength, real time, and in-vivo technique to detect breast cancer. Preliminary...

Bendele, Travis Henry

2013-02-22T23:59:59.000Z

483

An inheritance and cytological study of angular leaf spot resistance in the F? generation of a gossypium three-species hybrid  

E-Print Network [OSTI]

dissemination of angular leaf spot. However, Rolf (1935) and Tennyson (1936) believe the seed to be the primary source of infection. Tennyson found that under favorable conditions the seedling infection resulting from internal contamination may reach 20... percent or more. Rolf (1930-32) observed that most of the infection is found on the outer seed coat with only three percent of the infection within the seed. Rogers (19U3) and Ray (19U7) report that seed treatment is benefi? cial for controlling...

Bradford, Willis Warren

2013-10-04T23:59:59.000Z

484

A Monte Carlo procedure for the construction of complementary cumulative distribution functions for comparison with the EPA release limits for radioactive waste disposal  

SciTech Connect (OSTI)

A Monte Carlo procedure for the construction of complementary cumulative distribution functions (CCDFs) for comparison with the US Environmental Protection Agency (EPA) release limits for radioactive waste disposal (40 CFR 191, Subpart B) is described and illustrated with results from a recent performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP). The Monte Carlo procedure produces CCDF estimates similar to those obtained with stratified sampling in several recent PAs for the WIPP. The advantages of the Monte Carlo procedure over stratified sampling include increased resolution in the calculation of probabilities for complex scenarios involving drilling intrusions and better use of the necessarily limited number of mechanistic calculations that underlie CCDF construction.

Helton, J.C.; Shiver, A.W.

1994-10-01T23:59:59.000Z

485

Lipid droplets fusion in adipocyte differentiated 3T3-L1 cells: A Monte Carlo simulation  

SciTech Connect (OSTI)

Several human worldwide diseases like obesity, type 2 diabetes, hepatic steatosis, atherosclerosis and other metabolic pathologies are related to the excessive accumulation of lipids in cells. Lipids accumulate in spherical cellular inclusions called lipid droplets (LDs) whose sizes range from fraction to one hundred of micrometers in adipocytes. It has been suggested that LDs can grow in size due to a fusion process by which a larger LD is obtained with spherical shape and volume equal to the sum of the progenitors’ ones. In this study, the size distribution of two populations of LDs was analyzed in immature and mature (5-days differentiated) 3T3-L1 adipocytes (first and second populations, respectively) after Oil Red O staining. A Monte Carlo simulation of interaction between LDs has been developed in order to quantify the size distribution and the number of fusion events needed to obtain the distribution of the second population size starting from the first one. Four models are presented here based on different kinds of interaction: a surface weighted interaction (R2 Model), a volume weighted interaction (R3 Model), a random interaction (Random model) and an interaction related to the place where the LDs are born (Nearest Model). The last two models mimic quite well the behavior found in the experimental data. This work represents a first step in developing numerical simulations of the LDs growth process. Due to the complex phenomena involving LDs (absorption, growth through additional neutral lipid deposition in existing droplets, de novo formation and catabolism) the study focuses on the fusion process. The results suggest that, to obtain the observed size distribution, a number of fusion events comparable with the number of LDs themselves is needed. Moreover the MC approach results a powerful tool for investigating the LDs growth process. Highlights: • We evaluated the role of the fusion process in the synthesis of the lipid droplets. • We compared the size distribution of the lipid droplets in immature and mature cells. • We used the Monte Carlo simulation approach, simulating 10 thousand of fusion events. • Four different interaction models between the lipid droplets were tested. • The best model which mimics the experimental measures was selected.

Boschi, Federico, E-mail: federico.boschi@univr.it [Department of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, 37134 Verona (Italy); Department of Computer Science, University of Verona, Strada Le Grazie 15, 37134 Verona (Italy); Rizzatti, Vanni; Zamboni, Mauro [Department of Medicine, Geriatric Section, University of Verona, Piazzale Stefani 1, 37126 Verona (Italy); Sbarbati, Andrea [Department of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, 37134 Verona (Italy)

2014-02-15T23:59:59.000Z

486

Monte Carlo and Analytical Calculation of Lateral Deflection of Proton Beams in Homogeneous Targets  

SciTech Connect (OSTI)

Proton radiation therapy is a precise form of radiation therapy, but the avoidance of damage to critical normal tissues and the prevention of geographical tumor misses require accurate knowledge of the dose delivered to the patient and the verification of his position demand a precise imaging technique. In proton therapy facilities, the X-ray Computed Tomography (xCT) is the preferred technique for the planning treatment of patients. This situation has been changing nowadays with the development of proton accelerators for health care and the increase in the number of treated patients. In fact, protons could be more efficient than xCT for this task. One essential difficulty in pCT image reconstruction systems came from the scattering of the protons inside the target due to the numerous small-angle deflections by nuclear Coulomb fields. The purpose of this study is the comparison of an analytical formulation for the determination of beam lateral deflection, based on Moliere's theory and Rutherford scattering with Monte Carlo calculations by SRIM 2008 and MCNPX codes.

Pazianotto, Mauricio T.; Inocente, Guilherme F.; Silva, Danilo Anacleto A. d; Hormaza, Joel M. [Departamento de Fisica e Biofisica-Instituto de Biociencias, Universidade Estadual Paulista 'Julio de Mesquita Filho'-Botucatu-SP, Brasil and Distrito de Rubiao Junior s/no 18608-000 Botucatu, SP (Brazil)

2010-05-21T23:59:59.000Z

487

Simulation of Watts Bar Unit 1 Initial Startup Tests with Continuous Energy Monte Carlo Methods  

SciTech Connect (OSTI)

The Consortium for Advanced Simulation of Light Water Reactors* is developing a collection of methods and software products known as VERA, the Virtual Environment for Reactor Applications. One component of the testing and validation plan for VERA is comparison of neutronics results to a set of continuous energy Monte Carlo solutions for a range of pressurized water reactor geometries using the SCALE component KENO-VI developed by Oak Ridge National Laboratory. Recent improvements in data, methods, and parallelism have enabled KENO, previously utilized predominately as a criticality safety code, to demonstrate excellent capability and performance for reactor physics applications. The highly detailed and rigorous KENO solutions provide a reliable nu-meric reference for VERAneutronics and also demonstrate the most accurate predictions achievable by modeling and simulations tools for comparison to operating plant data. This paper demonstrates the performance of KENO-VI for the Watts Bar Unit 1 Cycle 1 zero power physics tests, including reactor criticality, control rod worths, and isothermal temperature coefficients.

Godfrey, Andrew T [ORNL; Gehin, Jess C [ORNL; Bekar, Kursat B [ORNL; Celik, Cihangir [ORNL

2014-01-01T23:59:59.000Z

488

Thermodynamics and quark susceptibilities: a Monte-Carlo approach to the PNJL model  

E-Print Network [OSTI]

The Monte-Carlo method is applied to the Polyakov-loop extended Nambu--Jona-Lasinio (PNJL) model. This leads beyond the saddle-point approximation in a mean-field calculation and introduces fluctuations around the mean fields. We study the impact of fluctuations on the thermodynamics of the model, both in the case of pure gauge theory and including two quark flavors. In the two-flavor case, we calculate the second-order Taylor expansion coefficients of the thermodynamic grand canonical partition function with respect to the quark chemical potential and present a comparison with extrapolations from lattice QCD. We show that the introduction of fluctuations produces only small changes in the behavior of the order parameters for chiral symmetry restoration and the deconfinement transition. On the other hand, we find that fluctuations are necessary in order to reproduce lattice data for the flavor non-diagonal quark susceptibilities. Of particular importance are pion fields, the contribution of which is strictly zero in the saddle point approximation.

M. Cristoforetti; T. Hell; B. Klein; W. Weise

2010-02-11T23:59:59.000Z

489

Feasibility Study of Neutron Dose for Real Time Image Guided Proton Therapy: A Monte Carlo Study  

E-Print Network [OSTI]

Two full rotating gantry with different nozzles (Multipurpose nozzle with MLC, Scanning Dedicated nozzle) with conventional cyclotron system is installed and under commissioning for various proton treatment options at Samsung Medical Center in Korea. The purpose of this study is to investigate neutron dose equivalent per therapeutic dose, H/D, to x-ray imaging equipment under various treatment conditions with monte carlo simulation. At first, we investigated H/D with the various modifications of the beam line devices (Scattering, Scanning, Multi-leaf collimator, Aperture, Compensator) at isocenter, 20, 40, 60 cm distance from isocenter and compared with other research groups. Next, we investigated the neutron dose at x-ray equipments used for real time imaging with various treatment conditions. Our investigation showed the 0.07 ~ 0.19 mSv/Gy at x-ray imaging equipments according to various treatment options and intestingly 50% neutron dose reduction effect of flat panel detector was observed due to multi- lea...

Kim, Jin Sung; Kim, Daehyun; Shin, EunHyuk; Chung, Kwangzoo; Cho, Sungkoo; Ahn, Sung Hwan; Ju, Sanggyu; Chung, Yoonsun; Jung, Sang Hoon; Han, Youngyih

2015-01-01T23:59:59.000Z

490

RESPONSE FUNCTION OF THE BGO AND NAI(T1) DETECTORS USING MONTE CARLO SIMULATIONS.  

SciTech Connect (OSTI)

The high efficiency of the BGO detectors makes them very attractive candidates to replace NaI(T1) detectors, which are widely used in studies of body composition. In this work, the response functions of the BGO and NaI(T1) detectors were determined at 0.662,4.4, and 10.0 MeV using three different Monte Carlo codes: EGS4, MCNP, and PHOTON. These codes differ in their input files and transport calculations, and were used to verify the internal consistency of the setup and of the input data. The energy range of 0.662 to 10 MeV was chosen to cover energies of interest in body composition-studies. The superior efficiency of the BGO-detectors has to be weighed-against their inferior resolution, and their higher price than that of the NaI detectors. Because the price of the BGO detectors strongly depends on the size of the crystal, its optimization is an important component in the design of the entire system.

Orion, I.; Wielopolski, L.

2001-01-31T23:59:59.000Z

491

Full-dispersion Monte Carlo simulation of phonon transport in micron-sized graphene nanoribbons  

SciTech Connect (OSTI)

We simulate phonon transport in suspended graphene nanoribbons (GNRs) with real-space edges and experimentally relevant widths and lengths (from submicron to hundreds of microns). The full-dispersion phonon Monte Carlo simulation technique, which we describe in detail, involves a stochastic solution to the phonon Boltzmann transport equation with the relevant scattering mechanisms (edge, three-phonon, isotope, and grain boundary scattering) while accounting for the dispersion of all three acoustic phonon branches, calculated from the fourth-nearest-neighbor dynamical matrix. We accurately reproduce the results of several experimental measurements on pure and isotopically modified samples [S. Chen et al., ACS Nano 5, 321 (2011);S. Chen et al., Nature Mater. 11, 203 (2012); X. Xu et al., Nat. Commun. 5, 3689 (2014)]. We capture the ballistic-to-diffusive crossover in wide GNRs: room-temperature thermal conductivity increases with increasing length up to roughly 100??m, where it saturates at a value of 5800?W/m K. This finding indicates that most experiments are carried out in the quasiballistic rather than the diffusive regime, and we calculate the diffusive upper-limit thermal conductivities up to 600?K. Furthermore, we demonstrate that calculations with isotropic dispersions overestimate the GNR thermal conductivity. Zigzag GNRs have higher thermal conductivity than same-size armchair GNRs, in agreement with atomistic calculations.

Mei, S., E-mail: smei4@wisc.edu; Knezevic, I., E-mail: knezevic@engr.wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Maurer, L. N. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Aksamija, Z. [Department of Electrical and Computer Engineering, University of Massachusetts-Amherst, Amherst, Massachusetts 01003 (United States)