Powered by Deep Web Technologies
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.


1

Natural Gas Futures Prices (NYMEX) - Energy Information Administration  

U.S. Energy Information Administration (EIA)

The natural gas liquids (NGL) composite price is derived from daily Bloomberg spot price data for natural gas liquids at Mont Belvieu, Texas, ...

2

Spotted Inflation  

E-Print Network (OSTI)

We describe new scenarios of generating curvature perturbations when inflaton (curvaton) has significant interactions. We consider a ``spot'', which arises from interactions associated with enhanced symmetric point (ESP) on the trajectory. Our first example uses the spot to induce a gap to the field equation. We observe that the gap in the field equation may cause generation of curvature perturbation if it appears not simultaneous in space. The mechanism is similar to the scenario of inhomogeneous phase transition. Then we observe that the spot interactions may initiate warm inflation in the cold Universe. Creation of cosmological perturbation is discussed in relation to the inflaton dynamics and the modulation associated with the spot interactions.

Tomohiro Matsuda

2010-08-01T23:59:59.000Z

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

Discriminative keyword spotting  

Science Conference Proceedings (OSTI)

This paper proposes a new approach for keyword spotting, which is based on large margin and kernel methods rather than on HMMs. Unlike previous approaches, the proposed method employs a discriminative learning procedure, in which the learning phase aims ... Keywords: Discriminative models, Keyword spotting, Large margin and kernel methods, Speech recognition, Spoken term detection, Support vector machines

Joseph Keshet; David Grangier; Samy Bengio

2009-04-01T23:59:59.000Z

5

White Spots in Superalloys  

Science Conference Proceedings (OSTI)

Also, a brief description of detection methods ... (EDS) Analysis of the Discrete White Spot in the Alloy ..... 400°C (750'99, Load Control, R Ratio = 0. 164 .... Electric. 7. Reported at May, 1992 White Spots Workshop by S. Besse of SNECMA. 8.

6

Spot Distillate & Crude Oil Prices  

U.S. Energy Information Administration (EIA)

Retail distillate prices follow the spot distillate markets, and crude oil prices have been the main driver behind distillate spot price increases until recently.

7

Resistance Spot Welding  

Science Conference Proceedings (OSTI)

...or more sheetmetal stampings that do not require gas-tight or liquid-tight joints can be more economically joined by high-speed RSW than by mechanical methods. Containers frequently are spot welded. The attachment of

8

Natural Gas Spot Prices:  

Gasoline and Diesel Fuel Update (EIA)

4 of 26 4 of 26 Notes: Spot wellhead prices last summer averaged well over $4.00 per thousand cubic feet during a normally low-price season. During the fall, these prices stayed above $5.00 per thousand cubic feet, more than double the year-ago average price. In January, the spot wellhead price averaged a record $8.98 per thousand cubic feet. Spot prices at the wellhead have never been this high for such a prolonged period. The chief reason for these sustained high gas prices was, and still is, uneasiness about the supply situation. Concern about the adequacy of winter supplies loomed throughout most of the summer and fall as storage levels remained significantly depressed. Last December, the most severe assumptions about low storage levels became real, when the spot price

9

Reactor hot spot analysis  

SciTech Connect

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

10

Wholesale/Spot Henry Hub Spot Price ........  

Gasoline and Diesel Fuel Update (EIA)

Wholesale/Spot Wholesale/Spot Henry Hub Spot Price ........ 2.52 2.35 2.97 3.50 3.59 4.13 3.66 3.83 3.92 3.67 3.92 4.08 2.83 3.81 3.90 Residential New England ...................... 13.08 14.05 16.86 13.62 13.05 13.88 17.27 14.17 14.04 15.15 18.40 15.22 13.73 13.84 14.91 Middle Atlantic .................... 11.34 13.46 16.92 11.76 10.98 13.32 17.88 13.58 12.80 14.60 18.94 14.39 12.20 12.56 13.95 E. N. Central ...................... 8.30 10.68 15.52 8.57 7.74 10.79 15.82 9.37 8.80 11.38 17.13 10.31 9.20 9.15 10.13 W. N. Central ..................... 8.45 11.99 16.39 9.08 8.10 10.47 17.24 9.38 8.79 11.27 17.99 10.23 9.60 9.35 10.11 S. Atlantic ........................... 12.37 17.68 22.08 12.24 11.10 15.05 22.27 13.49 12.56 18.03 24.66 14.95 13.71 13.12 14.77 E. S. Central ....................... 10.26 14.69 17.56 10.41 9.25 12.36 18.26 11.50

11

Small Spot, Brighter Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Small Spot, Brighter Beam Small Spot, Brighter Beam Small Spot, Brighter Beam Print Do you notice the brighter beam? During the most recent shutdown, all of the corrector magnets were replaced with sextupoles, reducing the horizontal emittance and increasing beam brightness. "This is part of ongoing improvement to keep the ALS on the cutting edge," says Alastair MacDowell, a beamline scientist on Beamline 12.2.2. The brightness has increased by a factor of about three in the storage ring. Beamlines on superbend or center-bend magnets will see the most noticeable increase in brightness, but the horizontal beam size and divergence have been substantially reduced at all beamlines. "We are starting to approach the resolution of many beamlines. Therefore, not every beamline will be able to resolve the full improvement," says Christoph Steier, project leader of the brightness upgrade. Though superbend and center-bend magnet source sizes are reduced by roughly a factor of three, "measured improvements so far range from a factor of 2-2.5," Steier says. He and MacDowell agree that the beamline optics are likely the limiting factor in resolving the full improvement at the beamlines.

12

Average Weekly Propane Spot Prices  

Gasoline and Diesel Fuel Update (EIA)

7 Notes: Propane spot prices at the major trading hubs remained relatively close through October 2000, but uncoupled in California as natural gas prices rose rapidly during...

13

Hydrogen Delivery Liquefaction & Compression  

E-Print Network (OSTI)

SEPARATION PLANTS NITROGEN OXYGEN INDUSTRIAL AREA GALVESTON BAY GULF OF MEXICO BAYTOWN MONT BELVIEU Refrigeration GN2 to N2 Liquefier To Feed H2 Flash Compressor H2 Recycle Compressor LN2 Add. To Storage/Fill #12

14

New construction era reflected in East Texas LPG pipeline  

SciTech Connect

Installation of 240 miles of 6, 10, and 12-in. LPG pipelines from Mont Belvieu to Tyler, Tex., has provided greater feedstock-supply flexibility to a petrochemical plant in Longview, Tex. The project, which took place over 18 months, included tie-ins with metering at four Mont Belvieu suppliers. The new 10 and 12-in. pipelines now transport propane while the new and existing parts of a 6-in. pipeline transport propylene.

Mittler, T.J. (Texas Eastman Co., Longview, TX (US))

1990-04-02T23:59:59.000Z

15

Population Monte Carlo algorithms  

E-Print Network (OSTI)

We give a cross-disciplinary survey on ``population'' Monte Carlo algorithms. In these algorithms, a set of ``walkers'' or ``particles'' is used as a representation of a high-dimensional vector. The computation is carried out by a random walk and split/deletion of these objects. The algorithms are developed in various fields in physics and statistical sciences and called by lots of different terms -- ``quantum Monte Carlo'', ``transfer-matrix Monte Carlo'', ``Monte Carlo filter (particle filter)'',``sequential Monte Carlo'' and ``PERM'' etc. Here we discuss them in a coherent framework. We also touch on related algorithms -- genetic algorithms and annealed importance sampling.

Yukito IBA

2000-08-16T23:59:59.000Z

16

ClearSpot Energy | Open Energy Information  

Open Energy Info (EERE)

Energy Jump to: navigation, search Name ClearSpot Energy Sector Solar Product US-based solar project developer for rooftop commercial installations. References ClearSpot...

17

Monte Carlo fundamentals  

SciTech Connect

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

18

How to spot a nuke  

NLE Websites -- All DOE Office Websites (Extended Search)

How to spot a nuke How to spot a nuke 1663 Los Alamos science and technology magazine Latest Issue:November 2013 All Issues » submit How to spot a nuke Neutrons set loose by a high-power laser can identify illicit nuclear materials inside closed containers. November 25, 2013 How to spot a nuke Could you identify dangerous nuclear materials inside this box if it weren't labeled? We can. Laser-driven blast of neutrons reveals concealed nuclear bomb materials Los Alamos scientists recently demonstrated a new laser-based technique for producing a burst of neutrons capable of revealing the presence of illicit nuclear materials, such as plutonium. "No one knew it could actually be done," said Andrea Favalli, one of the team leaders, "until we worked out the details, fabricated the parts, and performed the test." The

19

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

20

Average Weekly Propane Spot Prices  

Gasoline and Diesel Fuel Update (EIA)

19 Notes: Propane spot prices at the major trading hubs remained relatively close through the fall of 2000, even as they were pushed higher by rapidly rising natural gas prices....

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

Average Weekly Propane Spot Prices  

Gasoline and Diesel Fuel Update (EIA)

9 Notes: Propane spot prices at the major trading hubs remained relatively close through the fall of 2000, even as they were pushed higher by rapidly rising natural gas prices....

22

Quantum Monte Carlo for  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum Monte Carlo for the Electronic Structure of Atoms and Molecules Brian Austin Lester Group, U.C. Berkeley BES Requirements Workshop Rockville, MD February 9, 2010 Outline...

23

A procedure to determine the planar integral spot dose values of proton pencil beam spots  

Science Conference Proceedings (OSTI)

Purpose: Planar integral spot dose (PISD) of proton pencil beam spots (PPBSs) is a required input parameter for beam modeling in some treatment planning systems used in proton therapy clinics. The measurement of PISD by using commercially available large area ionization chambers, like the PTW Bragg peak chamber (BPC), can have large uncertainties due to the size limitation of these chambers. This paper reports the results of our study of a novel method to determine PISD values from the measured lateral dose profiles and peak dose of the PPBS. Methods: The PISDs of 72.5, 89.6, 146.9, 181.1, and 221.8 MeV energy PPBSs were determined by area integration of their planar dose distributions at different depths in water. The lateral relative dose profiles of the PPBSs at selected depths were measured by using small volume ion chambers and were investigated for their angular anisotropies using Kodak XV films. The peak spot dose along the beam's central axis (D{sub 0}) was determined by placing a small volume ion chamber at the center of a broad field created by the superposition of spots at different locations. This method allows eliminating positioning uncertainties and the detector size effect that could occur when measuring it in single PPBS. The PISD was then calculated by integrating the measured lateral relative dose profiles for two different upper limits of integration and then multiplying it with corresponding D{sub 0}. The first limit of integration was set to radius of the BPC, namely 4.08 cm, giving PISD{sub RBPC}. The second limit was set to a value of the radial distance where the profile dose falls below 0.1% of the peak giving the PISD{sub full}. The calculated values of PISD{sub RBPC} obtained from area integration method were compared with the BPC measured values. Long tail dose correction factors (LTDCFs) were determined from the ratio of PISD{sub full}/PISD{sub RBPC} at different depths for PPBSs of different energies. Results: The spot profiles were found to have angular anisotropy. This anisotropy in PPBS dose distribution could be accounted in a reasonable approximate manner by taking the average of PISD values obtained using the in-line and cross-line profiles. The PISD{sub RBPC} values fall within 3.5% of those measured by BPC. Due to inherent dosimetry challenges associated with PPBS dosimetry, which can lead to large experimental uncertainties, such an agreement is considered to be satisfactory for validation purposes. The PISD{sub full} values show differences ranging from 1 to 11% from BPC measured values, which are mainly due to the size limitation of the BPC to account for the dose in the long tail regions of the spots extending beyond its 4.08 cm radius. The dose in long tail regions occur both for high energy beams such as 221.8 MeV PPBS due to the contributions of nuclear interactions products in the medium, and for low energy PPBS because of their larger spot sizes. The calculated LTDCF values agree within 1% with those determined by the Monte Carlo (MC) simulations. Conclusions: The area integration method to compute the PISD from PPBS lateral dose profiles is found to be useful both to determine the correction factors for the values measured by the BPC and to validate the results from MC simulations.

Anand, Aman; Sahoo, Narayan; Zhu, X. Ronald; Sawakuchi, Gabriel O.; Poenisch, Falk; Amos, Richard A.; Ciangaru, George; Titt, Uwe; Suzuki, Kazumichi; Mohan, Radhe; Gillin, Michael T. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Box 1150, Houston, Texas 77030 (United States)

2012-02-15T23:59:59.000Z

24

Translation spotting for translation memories  

Science Conference Proceedings (OSTI)

The term translation spotting (TS) refers to the task of identifying the target-language (TL) words that correspond to a given set of source-language (SL) words in a pair of text segments known to be mutual translations. This article examines ...

Michel Simard

2003-05-01T23:59:59.000Z

25

MIKE TURNER ON SPOTTING YOUNG  

E-Print Network (OSTI)

BAE SYSTEMS MIKE TURNER ON SPOTTING YOUNG TALENT AND THE GROWTH OF HIS BUSINESS Success stories? Surely, it is about making lots of money, gaining power, status and prestige, and then using this wealth, the extinction of many animal and plant species, and global warming demonstrated that the raw materials

26

Natural Gas Spot Price Outlook  

Gasoline and Diesel Fuel Update (EIA)

7 of 17 7 of 17 Notes: Despite signs that domestic natural gas production has begun to turn around (the Texas Railroad Commission now reports year-to-date (through Sep.) gains in Texas gas production of 1.2 percent, compared to a 4.7-percent decline for the same months in 1999 versus 1998) the reality of the U.S. gas market is that supply responses have been too little, too late to prevent record-high spot prices and prospects for very high average prices this winter. We now expect to see peak monthly spot wellhead prices this winter of over $6.00 per thousand cubic feet (mcf) (December). Last month we maintained confidence that conditions would improve enough to keep the $5.10 per mcf recorded in October as the peak for this heating season. With partial data available, a monthly average value of about $5.60 per mcf looks likely for

27

HotSpot | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

HotSpot HotSpot HotSpot Current Central Registry Toolbox Version(s): 2.07.1 Code Owner: Department of Energy, Office of Emergency Operations and Lawrence Livermore National Laboratory (LLNL) Description: The HotSpot Health Physics Code is used for safety-analysis of DOE facilities handling nuclear material. Additionally, HotSpot provides emergency response personnel and emergency planners with a fast, field-portable set of software tools for evaluating incidents involving radioactive material. HotSpot provides a fast and usually conservative means for estimation of the radiation effects associated with atmospheric release of radioactive materials. The HotSpot atmospheric dispersion models are designed for near-surface releases, short-range (less than 10 km) dispersion, and short-term (less than 24 hours) release durations in

28

Monte Carlo Neutrino Oscillations  

E-Print Network (OSTI)

We demonstrate that the effects of matter upon neutrino propagation may be recast as the scattering of the initial neutrino wavefunction. Exchanging the differential, Schrodinger equation for an integral equation for the scattering matrix S permits a Monte Carlo method for the computation of S that removes many of the numerical difficulties associated with direct integration techniques.

James P. Kneller; Gail C. McLaughlin

2005-09-29T23:59:59.000Z

29

West Texas Intermediate Spot Average ............................  

U.S. Energy Information Administration (EIA) Indexed Site

Crude Oil (dollars per barrel) Crude Oil (dollars per barrel) West Texas Intermediate Spot Average ............................ 102.88 93.42 92.24 87.96 94.34 94.10 105.84 96.30 95.67 95.33 95.67 93.33 94.12 97.64 95.00 Brent Spot Average ........................................................... 118.49 108.42 109.61 110.09 112.49 102.58 110.27 108.29 106.33 105.00 103.00 102.00 111.65 108.41 104.08 Imported Average .............................................................. 108.14 101.18 97.18 97.64 98.71 97.39 103.07 100.03 99.64 99.33 99.69 97.35 101.09 99.85 99.04 Refiner Average Acquisition Cost ...................................... 107.61 101.44 97.38 97.27 101.14 99.45 105.24 100.44 100.15 99.82 100.18 97.83 100.83 101.61 99.50 Liquid Fuels (cents per gallon) Refiner Prices for Resale Gasoline .........................................................................

30

Detecting urbanization changes using SPOT5  

Science Conference Proceedings (OSTI)

An automatic system to estimate the urbanization changes on the Belgian territory, using SPOT5 images and the National Geographic Institute vectorial database is proposed. The images and the vectorial data are first co-registered. Then, the vectorial ... Keywords: Built-up area detection, Cartography, Change detection, SPOT5

V. Lacroix; M. Idrissa; A. Hincq; H. Bruynseels; O. Swartenbroekx

2006-03-01T23:59:59.000Z

31

Optimal Personal Comfort Management Using SPOT+  

Science Conference Proceedings (OSTI)

We present SPOT+, a system that allows office workers to optimally balance between heating energy consumption and personal thermal comfort. In prior work, we described SPOT: a smart personal thermal control system based on reactive control [8]. In contrast, ... Keywords: Energy management

Peter Xiang Gao, S. Keshav

2013-11-01T23:59:59.000Z

32

HotSpot Software Configuration Management Plan  

SciTech Connect

This Software Configuration Management Plan (SCMP) describes the software configuration management procedures used to ensure that the HotSpot dispersion model meets the requirements of its user base, which includes: (1) Users of the PC version of HotSpot for consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. This plan is intended to meet Critical Recommendations 1 and 3 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

Walker, H; Homann, S G

2009-03-12T23:59:59.000Z

33

Table Definitions, Sources, and Explanatory Notes  

Gasoline and Diesel Fuel Update (EIA)

Futures Prices Futures Prices Definitions Key Terms Definition Contract 1 A futures contract specifying the earliest delivery date. Natural gas contracts expire three business days prior to the first calendar day of the delivery month. Thus, the delivery month for Contract 1 is the calendar month following the trade date. Contract 2-4 Represent the successive delivery months following Contract 1. Futures Price The price quoted for delivering a specified quantity of a commodity at a specified time and place in the future. Natural Gas A gaseous mixture of hydrocarbon compounds, the primary one being methane. NGL Composite Price The natural gas liquids (NGL) composite price is derived from daily Bloomberg spot price data for natural gas liquids at Mont Belvieu, Texas, weighted by gas processing plant production volumes of each product as reported on Form EIA-816, "Monthly Natural Gas Liquids Report."

34

Average wholesale spot natural gas prices rose across the country ...  

U.S. Energy Information Administration (EIA)

Wholesale spot natural gas prices rose across the country in 2010. Average spot natural gas prices at the Henry Hub—a key benchmark location for pricing throughout ...

35

Building Energy Software Tools Directory: SPOT  

NLE Websites -- All DOE Office Websites (Extended Search)

SPOT SPOT SPOT screen image Quantifies existing or intended electric lighting performance, evaluate annual daylighting characteristics and help establish the optimal photosensor placement in a given space relative to annual performance and annual energy savings. The Sensor Placement and Optimization Tool, or SPOT, was developed with classroom daylighting in mind, but can be used for all types of spaces. Screen Shots Keywords daylighting, electric lighting, photosensor, energy savings Validation/Testing Various individuals have tested the software. Testing and validation continues. Documentation of the test and validation results are available on the web site. Expertise Required Energy engineering or lighting design background is helpful for analysis of results. A working familiarity with Excel may be helpful, but it is not

36

Spot Distillate & Crude Oil Prices  

Gasoline and Diesel Fuel Update (EIA)

5 5 Notes: Retail distillate prices follow the spot distillate markets, and crude oil prices have been the main driver behind distillate spot price increases until recently. Crude oil rose about 36 cents per gallon from its low point in mid February 1999 to the middle of January 2000. Over this same time period, New York Harbor spot heating oil had risen about 42 cents per gallon, reflecting both the crude price rise and a return to a more usual seasonal spread over the price of crude oil. The week ending January 21, heating oil spot prices in the Northeast spiked dramatically to record levels, closing on Friday at $1.26 per gallon -- up 50 cents from the prior week. Gulf Coast prices were not spiking, but were probably pulled slightly higher as the New York Harbor market began to

37

Retail Price Changes Lag Spot Prices  

Gasoline and Diesel Fuel Update (EIA)

1 1 Notes: While EIA cannot claim to explain all of the factors that drive retail gasoline prices, we have had a fair amount of success in exploring the relationship between wholesale and retail prices. In particular, we have looked closely at the "pass-through" of changes in spot prices to the retail market. This graph shows a weighted national average of spot prices for regular gasoline -both conventional and reformulated (shown in red), and EIA's weekly survey price for retail regular (again both conventional and reformulated). As you can see, spot prices tend to be more volatile (and would be even more so on a daily basis), while these changes are smoother by the time they reach the retail pump. Furthermore, by looking at the peaks, you can see the retail prices seem to lag the spot price changes

38

2013 ORNL Audio Spots | ornl.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

3 2013 ORNL Audio Spots 1-10 of 26 Results Prev 123 Next ORNL working to strengthen seals for nuclear containers OAK RIDGE, Tenn., Dec. 19, 2013 - The Department of Energy's Oak...

39

Natural Gas Spot Prices: - Energy Information Administration  

U.S. Energy Information Administration (EIA)

Spot wellhead prices last summer averaged well over $4.00 per thousand cubic feet during a normally low-price season. During the fall, these prices stayed above $5.00 ...

40

Measuring microfocus focal spots using digital radiography  

SciTech Connect

Measurement of microfocus spot size can be important for several reasons: (1) Quality assurance during manufacture of microfocus tubes; (2) Tracking performance and stability of microfocus tubes; (3) Determining magnification (especially important for digital radiography where the native spatial resolution of the digital system is not adequate for the application); (4) Knowledge of unsharpness from the focal spot alone. The European Standard EN 12543-5 is based on a simple geometrical method of calculating focal spot size from unsharpness of high magnification film radiographs. When determining microfocus focal spot dimensions using unsharpness measurements both signal-to-noise (SNR) and magnification can be important. There is a maximum accuracy that is a function of SNR and therefore an optimal magnification. Greater than optimal magnification can be used but it will not increase accuracy.

Fry, David A [Los Alamos National Laboratory

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

Chicago Gasoline - WTI Spot Spread - U.S. Energy Information ...  

U.S. Energy Information Administration (EIA)

Chicago Gasoline - WTI Spot Spread. Previous slide: Next slide: Back to first slide: View graphic version

42

Monte Carlo Methods and Partial Differential Equations ...  

Science Conference Proceedings (OSTI)

... Up, Monte Carlo Methods and Partial Differential Equations: Algorithms and Implications for High-Performance Computing. ...

2013-08-16T23:59:59.000Z

43

Strategic Spot Trading in Supply Chains  

Science Conference Proceedings (OSTI)

In a variety of industries ranging from agriculture to electronics and oil, procurement takes place through a combination of bilateral fixed-price contracts and open market trading among supply chain participants, which allows them to improve supply ... Keywords: demand and cost information, fixed-price contracts, procurement and supply chain, spot trading

Haim Mendelson; Tunay I. Tunca

2007-05-01T23:59:59.000Z

44

Measuring microfocal spots using digital radiography  

SciTech Connect

Measurement of microfocus spot size can be important for several reasons: (1) Quality assurance during manufacture of microfocus tubes; (2) Tracking performance and stability of microfocus tubes; (3) Determining magnification is especially important for digital radiography where the native spatial resolution of the digital system is not adequate for the application; and (4) Knowledge of unsharpness from the focal spot alone. The European Standard EN 12543-5 is based on a simple geometrical method of calculating focal spot size from unsharpness of high magnification film radiographs. The following equations are used for the focal spot size measurement: By similar triangles the following equations are presupposed: f/a = U/b and M = (a+b)/a. These equations can be combined to yield the well known expression: U = f(M - 1). Solving for f, f = U/(M-1). Therefore, the focal spot size, f, can be calculated by measuring the radiographic unsharpness and magnification of a known object. This is the basis for these tests. The European standard actually uses one-half of the unsharpness (which are then added together) from both sides of the object to avoid additional unsharpness contributions due to edge transmission unsharpness of the round test object (the outside of the object is measured). So the equation becomes f = (1/2 U{sub 1} + 1/2 U{sub 2})/(M-1). In practice 1/2 U is measured from the 50% to the 90% signal points on the transition profile from ''black'' to ''white,'' (positive image) or attenuated to unattenuated portion of the image. The 50% to 90% points are chosen as a best fit to an assumed Gaussian radiation distribution from the focal spot and to avoid edge transmission effects. 1/2 U{sub 1} + 1/2 U{sub 2} corresponds about to the full width at half height of a Gaussian focal spot. A highly absorbing material (Tungsten, Tungsten Alloy, or Platinum) is used for the object. Either wires or a sphere are used as the object to eliminate alignment issues. One possibility is to use the wires in the ASTM E2002 unsharpness gage and take two orthogonal images. The signal levels in the image need to be linear with radiation exposure and so may need conversion if a nonlinear detector is used to acquire the image.

Fry, David A [Los Alamos National Laboratory; Ewert, Uwe [BAM

2009-01-01T23:59:59.000Z

45

Training Program EHS ~ 244: Resistance Spot Welding Safety Training  

NLE Websites -- All DOE Office Websites (Extended Search)

4: Resistance Spot Welding Safety Training 4: Resistance Spot Welding Safety Training Course Syllabus Subject Category: Resistance Spot Welding Course Prerequisite: None Course Length: 25 minutes Medical Approval: No Delivery Mode: Web-Based Course Goal: Participants will be introduced to resistance spot welding processes, hazards, and safe work practices. Course Objectives: By the end of this course, you will be able to: * Identify resistance spot welding processes * Identify hazards, safe work practices, and personal protective equipment associated with resistance spot welding * Recognize the purpose of resistance spot welding schedules * Locate resistance spot welding schedule Subject Matter Expert: Joe Dionne x 7586 Training Compliance: 29 CFR 1910 Subparts O & Z, 29 CFR 1926 Subparts J & Z

46

Figure 86. Annual average Henry Hub spot natural gas prices ...  

U.S. Energy Information Administration (EIA)

Sheet3 Sheet2 Sheet1 Figure 86. Annual average Henry Hub spot natural gas prices, 1990-2040 (2011 dollars per million Btu) Henry Hub Spot Price 1990.00

47

Weekly Cushing, OK WTI Spot Price FOB (Dollars per Barrel)  

U.S. Energy Information Administration (EIA)

Weekly Cushing, OK WTI Spot Price FOB (Dollars per Barrel) Year-Month Week 1 Week 2 Week 3 Week 4 ... Spot Prices for Crude Oil and Petroleum Products ...

48

Spot natural gas prices at Marcellus trading point reflect ...  

U.S. Energy Information Administration (EIA)

... the spot price of natural gas at the TGP Zone 4 Marcellus trading point has fallen—at times considerably—below the spot price at Henry Hub in Louisiana, ...

49

Europe Brent Spot Price FOB (Dollars per Barrel)  

U.S. Energy Information Administration (EIA)

Europe Brent Spot Price FOB (Dollars per Barrel) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 Year-6 Year-7 ... Spot Prices for Crude Oil and Petroleum Products ...

50

Cushing, OK WTI Spot Price FOB (Dollars per Barrel)  

U.S. Energy Information Administration (EIA)

View History: Daily Weekly Monthly Annual : Download Data (XLS File) Cushing, OK ... Spot Prices for Crude Oil and Petroleum Products ...

51

The fractal nature of vacuum arc cathode spots  

E-Print Network (OSTI)

plasma-emitting) spot fragment will increase its area in time (~10-100 ns timescale) due to heat conduction,

Anders, Andre

2005-01-01T23:59:59.000Z

52

Europe Brent Spot Price FOB (Dollars per Barrel)  

U.S. Energy Information Administration (EIA)

View History: Daily Weekly Monthly Annual : Download Data (XLS File) Europe ... Spot Prices for Crude Oil and Petroleum Products ...

53

Spot Ventilation: Source Control to Improve Indoor Air Quality  

SciTech Connect

Fact sheet for homeowners and contractors on how to employ spot ventilation in the home for comfort and safety.

2002-12-01T23:59:59.000Z

54

Monte Carlo Methods in Chemistry  

Science Conference Proceedings (OSTI)

Monte Carlo methods fulfil an important dual role. At a specific level, they provide a general-purpose numerical approach to problems in a wide range of topics. Using such methods, we can explore the characteristics of specific systems without introducing ...

Jim Doll; David L. Freeman

1994-03-01T23:59:59.000Z

55

Lexicon-free handwritten word spotting using character HMMs  

Science Conference Proceedings (OSTI)

For retrieving keywords from scanned handwritten documents, we present a word spotting system that is based on character Hidden Markov Models. In an efficient lexicon-free approach, arbitrary keywords can be spotted without pre-segmenting text lines ... Keywords: Handwriting recognition, Hidden Markov Models, Keyword spotting

Andreas Fischer; Andreas Keller; Volkmar Frinken; Horst Bunke

2012-05-01T23:59:59.000Z

56

Automated Spot Weld Inspection using Infrared Thermography  

Science Conference Proceedings (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; Zhang, Wei [ORNL; Yu, Zhenzhen [ORNL; Feng, Zhili [ORNL

2012-01-01T23:59:59.000Z

57

Friction Stir Spot Welding of Advanced High Strength Steels  

Science Conference Proceedings (OSTI)

Friction stir spot welding techniques were developed to successfully join several advanced high strength steels. Two distinct tool materials were evaluated to determine the effect of tool materials on the process parameters and joint properties. Welds were characterized primarily via lap shear, microhardness, and optical microscopy. Friction stir spot welds were compared to the resistance spot welds in similar strength alloys by using the AWS standard for resistance spot welding high strength steels. As further comparison, a primitive cost comparison between the two joining processes was developed, which included an evaluation of the future cost prospects of friction stir spot welding in advanced high strength steels.

Hovanski, Yuri; Grant, Glenn J.; Santella, M. L.

2009-11-13T23:59:59.000Z

58

Phase-resolved spectroscopy of Geminga shows rotating hot spot(s)  

E-Print Network (OSTI)

Isolated neutron stars are seen in x-rays through their nonthermal and/or surface thermal emissions. XMM-Newton observations of the Geminga pulsar show a 43 electron volt spectrum from the whole neutron star surface, as well as a power-law component above 2 kiloelectron volts. In addition, we have detected a hot (170 electron volts) thermal emission from an 60-meter-radius spot on the pulsar s surface. Such a thermal emission, only visible at selected phase intervals, may be coming from polar hot spot(s), long thought to exist as a result of heating from magnetospheric accelerated particles. It may provide the missing link between the x-ray and gamma-ray emission of the pulsar.

P. A. Caraveo; A. De Luca; S. Mereghetti; A. Pellizzoni; G. F. Bignami

2004-07-19T23:59:59.000Z

59

Mont Vista Capital LLC | Open Energy Information  

Open Energy Info (EERE)

Vista Capital LLC Vista Capital LLC Jump to: navigation, search Name Mont Vista Capital LLC Place New York, New York Zip 10167 Sector Services Product Mont Vista Capital is a leading global provider of services to clients in the alternative energy industry. Mont Vista also seeks proprietary trading and growth equity opportunities in alternative energy markets which add value for our stakeholders. References Mont Vista Capital LLC[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Mont Vista Capital LLC is a company located in New York, New York . References ↑ "Mont Vista Capital LLC" Retrieved from "http://en.openei.org/w/index.php?title=Mont_Vista_Capital_LLC&oldid=348916"

60

Spot Distillate & Crude Oil Prices  

Gasoline and Diesel Fuel Update (EIA)

mid-January, 2000. WTI crude oil price rose about $17 per mid-January, 2000. WTI crude oil price rose about $17 per barrel or 40 cents per gallon from its low point in mid February 1999 to January 17, 2000. Over this same time period, New York Harbor spot heating oil had risen about 42 cents per gallon, reflecting both the crude price rise and the beginning of a return to a more usual seasonal spread over the price of crude oil. The week ending January 21, distillate spot prices in the Northeast spiked dramatically to record levels, closing on Friday at $1.26 per gallon -- up 50 cents from the prior week. Gulf Coast prices were not spiking, but were probably pulled higher as the New York Harbor market began to draw on product from other areas. They closed at 83 cents per gallon, an increase of 11 cents from the prior Friday. Crude oil had risen about 4 cents from

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

RAS Gene Hot-Spot Mutations in  

E-Print Network (OSTI)

Point mutations in the cellular homologues HRAS, KRAS2, and NRAS of the viral Harvey and Kirsten rat sarcoma virus oncogenes are commonly involved in the onset of malignancies in humans and other species such as dog, mouse, and rat. Most often, three particular hot-spot codons are affected, with one amino acid exchange being sufficient for the induction of tumor growth. While RAS genes have been shown to play an important role in canine tumors such as non-small lung cell carcinomas, data about RAS mutations in canine fibrosarcomas as well as KRAS2 mutations in canine melanomas is sparse. To increase the number of tumors examined, we recently screened 13 canine fibrosarcomas and 11 canine melanomas for point mutations, particularly within the mutational hot spots. The results were compared to the already existing data from other studies about these tumors in dogs. A family of genes often involved in human tumors are the well-characterized RAS genes, which comprise HRAS, KRAS2, and NRAS, coding for closely related, small, 189 amino acid, 21 kDa, membrane-bound, intracellular proteins. The human cellular HRAS and KRAS2 genes were identified to be homologues of the Harvey and Kirsten rat sarcoma

Canine Neoplasias; J. Bullerdiek

2005-01-01T23:59:59.000Z

62

Sensor Placement + Optimization Software (SPOT) | Open Energy Information  

Open Energy Info (EERE)

Sensor Placement + Optimization Software (SPOT) Sensor Placement + Optimization Software (SPOT) Jump to: navigation, search Tool Summary Name: SPOT Agency/Company /Organization: Architectural Energy Corporation Sector: Energy Focus Area: Buildings, Energy Efficiency Topics: Technology characterizations Resource Type: Software/modeling tools User Interface: Spreadsheet Website: www.archenergy.com/SPOT/ Cost: Free Language: English References: http://www.archenergy.com/SPOT/ SPOT(tm) is intended to assist a designer in quantifying the existing or intended electric lighting and annual daylighting characteristics of a given space and to help establish the optimal photosensor placement for the space relative to annual performance and annual energy savings. The software was developed with classroom daylighting in mind, but can be used

63

Average prices for spot sulfur dioxide emissions allowances at ...  

U.S. Energy Information Administration (EIA)

The weighted average spot price for sulfur dioxide (SO 2) emissions allowances awarded to winning bidders at Environmental Protection Agency's (EPA) annual auction on ...

64

Cushing, OK WTI Spot Price FOB (Dollars per Barrel)  

U.S. Energy Information Administration (EIA)

Release Date: 10/9/2013: Next Release Date: 10/17/2013: Referring Pages: Spot Prices for Crude Oil and Petroleum Products

65

Central Appalachian (CAPP) coal spot prices affect markets for ...  

U.S. Energy Information Administration (EIA)

Note: Bloomberg prices for the prompt month have been shifted forward by one month to show the spot versus delivered price for the same month.

66

Pipeline constraints raise average spot natural gas prices in the ...  

U.S. Energy Information Administration (EIA)

The chart shows that spot natural gas prices for Henry Hub, Chicago, ... and gas from Pennsylvania storage fields on to Atlantic coast markets. ...

67

Spot natural gas prices at Marcellus trading point reflect ...  

U.S. Energy Information Administration (EIA)

Daily natural gas spot prices between Tennessee Gas Pipeline ... Dry natural gas production in Pennsylvania, a key part of the Marcellus supply basin, ...

68

The development of a UK natural gas spot market  

SciTech Connect

The growth of a natural gas spot market in the United Kingdom (UK) is a radical innovation for the industry. Spot markets turned the oil industry inside out, and will do the same for gas. Such a development seemed all but impossible to gas industry experts three years ago. The role and likely form of a spot market are now at the center of current industry debate about the designing of a daily balancing regime to replace unitary management by British Gas. This paper examines parallels between the evolution of spot markets for oil in the 1980`s and the current UK gas industry. 12 refs., 1 fig.

Roeber, J. [Joe Roeber Associates, London (United Kingdom)

1996-12-01T23:59:59.000Z

69

Care for a Spot of (Green) Tea? New NIST Reference ...  

Science Conference Proceedings (OSTI)

Care for a Spot of (Green) Tea? ... Green tea has been long prized not only for its taste but also for purported health benefits and medicinal value. ...

2012-10-15T23:59:59.000Z

70

Cushing, OK WTI Spot Price FOB (Dollars per Barrel)  

U.S. Energy Information Administration (EIA)

View History: Daily Weekly Monthly Annual : Download Data (XLS File) Cushing, OK WTI Spot Price FOB (Dollars per Barrel) Week Of Mon Tue Wed Thu Fri ; 1985 ...

71

Europe Brent Spot Price FOB (Dollars per Barrel)  

U.S. Energy Information Administration (EIA)

View History: Daily Weekly Monthly Annual : Download Data (XLS File) Europe Brent Spot Price FOB (Dollars per Barrel) Week Of Mon Tue Wed Thu Fri ; 1987 ...

72

Los Alamos Lab: NSO: Hot Spot: Director's Papers, Reviews  

NLE Websites -- All DOE Office Websites (Extended Search)

National Security Office. The Hot Spot page lists recently published Director's papers, book reviews, etc. Director's Paper: Safeguards at 40, LANL Director Michael Anastasio (pdf)...

73

Forecasting Crude Oil Spot Price Using OECD Petroleum Inventory Levels  

U.S. Energy Information Administration (EIA)

Forecasting Crude Oil Spot Price Using OECD Petroleum Inventory Levels MICHAEL YE,? JOHN ZYREN,?? AND JOANNE SHORE?? Abstract This paper presents a short ...

74

Spot price for Central Appalachian coal up since early 2010 ...  

U.S. Energy Information Administration (EIA)

Average spot prices for Central Appalachian (CAPP) coal are up about 36% since January, 2010. Contributing factors include: global supply disruptions, slightly ...

75

Average Weekly Propane Spot Prices - Energy Information Administration  

U.S. Energy Information Administration (EIA)

Propane spot prices at the major trading hubs remained relatively close through the fall of 2000, even as they were pushed higher by rapidly rising natural gas prices.

76

Average Weekly Propane Spot Prices - Energy Information Administration  

U.S. Energy Information Administration (EIA)

Propane spot prices at the major trading hubs remained relatively close through October 2000, but uncoupled in California as natural gas prices rose rapidly during ...

77

The path forward: Monte Carlo Convergence discussion  

SciTech Connect

This is a summary of 'the path forward' discussion session of the NuInt09 workshop which focused on Monte Carlo event generators. The main questions raised as part of this discussion are: how to make Monte Carlo generators more reliable and how important it is to work on a universal Monte Carlo generator of events? In this contribution, several experts in the field summarize their views, as presented at the workshop.

Andreopoulos, Costas [Rutherford Appleton Laboratory, STFC Oxfordshire OX11 0QX (United Kingdom); Gallagher, Hugh [Tufts University, Medford, Massachusetts (United States); Hayato, Yoshinari [Kamioka Observatory, ICRR, University of Tokyo Higashi-Mozumi 456, Kamioka-cho, Hida-city Gifu 506-1205 (Japan); Sobczyk, Jan T. [Institute of Theoretical Physics, Wroclaw, University Poland (Poland); Walter, Chris [Department of Physics, Duke University, Durham, NC 27708 (United States); Zeller, Sam [Los Alamos National Laboratory, Los Alamos, NM (United States)

2009-11-25T23:59:59.000Z

78

Spotted Wing Drosophila Management in Maryland Small Fruit  

E-Print Network (OSTI)

Spotted Wing Drosophila Management in Maryland Small Fruit Gerald Brust IPM Vegetable Specialist Sept. 2011 Spotted wing drosophila (SWD), Drosophila suzukii, is an invasive, destructive pest due to human intervention. Identification SWD adults are small (2-3 mm) flies with red eyes and a pale

Mohaghegh, Shahab

79

Sourcing Flexibility, Spot Trading, and Procurement Contract Structure  

Science Conference Proceedings (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' products, and we jointly endogenize ... Keywords: contract pricing, procurement, supply chain management

Pamela Pen-Erh Pei; David Simchi-Levi; Tunay I. Tunca

2011-05-01T23:59:59.000Z

80

Idealized Hot Spot Experiments with a General Circulation Model  

Science Conference Proceedings (OSTI)

Idealized experiments are conducted using a GCM coupled to a 20-m slab ocean model to examine the short-term response to an initial localized positive equatorial SST anomaly, or “hot spot.” A hot spot is imposed upon an aquaplanet with globally ...

Eric D. Maloney; Adam H. Sobel

2007-03-01T23:59:59.000Z

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

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

82

Optimal generalized truncated sequential Monte Carlo test  

Science Conference Proceedings (OSTI)

When it is not possible to obtain the analytical null distribution of a test statistic U, Monte Carlo hypothesis tests can be used to perform the test. Monte Carlo tests are commonly used in a wide variety of applications, including spatial statistics, ... Keywords: 62L05, 62L15, 65C05, Execution time, Power loss, Resampling risk, p-value density

Ivair R. Silva, Renato M. Assunção

2013-10-01T23:59:59.000Z

83

Dark spot formation relative to ITO surface roughness for polyfluorene  

NLE Websites -- All DOE Office Websites (Extended Search)

Dark spot formation relative to ITO surface roughness for polyfluorene Dark spot formation relative to ITO surface roughness for polyfluorene devices Title Dark spot formation relative to ITO surface roughness for polyfluorene devices Publication Type Journal Article Year of Publication 2004 Authors Liu, Gao, John B. Kerr, and Stephen G. Johnson Journal Synthetic Metals Volume 144 Pagination 1-6 Keywords dark spot, failure mechanism, interface, ito surface, oled Abstract The failure behaviors of ITO/PEDOT;PSS/polyfluorene/Al devices are different depending on the surface roughness of the sputtered ITO anode film. The spikes on ITO surface are responsible for the initial local shorts of the device, which develop into dark spots very quickly. Indium adsorption is observed on the polymer and Al cathode interface. A chemical etching procedure is used to smoothen the ITO surface without changing the ITO thickness and the sheet resistance. Devices made out of smooth ITO show minimum changes at polymer-cathode interface during operation.

84

Friction Stir Spot Welding of DP780 Carbon Steel  

Science Conference Proceedings (OSTI)

Friction stir spot welds were made in uncoated and galvannneled 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 1-10 s. Increasing tool rotation speed from 800 to 1600 rpm increased strength values. The 2-segment welding procedures also produced higher strength joints. Average lap-shear strengths exceeding 10.3 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, M. L.; Hovanski, Yuri; Frederick, Alan; Grant, Glenn J.; Dahl, Michael E.

2009-09-15T23:59:59.000Z

85

The MC21 Monte Carlo Transport Code  

SciTech Connect

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

86

Data Decomposition of Monte Carlo Particle Transport Simulations...  

NLE Websites -- All DOE Office Websites (Extended Search)

Data Decomposition of Monte Carlo Particle Transport Simulations via Tally Servers Title Data Decomposition of Monte Carlo Particle Transport Simulations via Tally Servers...

87

Wall and laser spot motion in cylindrical hohlraums  

Science Conference Proceedings (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

88

This Week In Petroleum Summary Printer-Friendly Version  

Gasoline and Diesel Fuel Update (EIA)

- Summary Printer-Friendly Version - Summary Printer-Friendly Version Released: January 15, 2014 Next Release: January 23, 2014 Midwest propane markets tighten further on cold weather The Upper Midwest is facing a tight market for propane this winter, as evidenced by a 1.5-million-barrel inventory draw in the region for the week ending last Friday, January 10. At the beginning of November, the corn harvest in the Upper Midwest (Minnesota, Iowa, Wisconsin, Nebraska) pulled large quantities of propane from distribution terminals for corn drying. Between late-November and December, supply disruptions prevented these terminals from replenishing their supplies of propane. With the onset of severely cold weather this past week, propane supplies are extremely tight, forcing emergency measures to ensure supply and increasing the Midwest spot price of propane at Conway, Kansas compared with the spot price on the Gulf Coast at Mont Belvieu, Texas. Propane prices in the Midwest will likely need to rise to keep propane in the region rather than flowing south to the Gulf Coast.

89

Exponential convergence with adaptive Monte Carlo  

Science Conference Proceedings (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

90

Canudos/Belo Monte: imagens contando história.  

E-Print Network (OSTI)

??O presente exercício objetiva construir uma leitura da Guerra de Canudos/Belo Monte tendo como documentos centrais as fotos de Flávio de Barros. Justifica-se tal trabalho… (more)

Sérgio Armando Diniz Guerra

2005-01-01T23:59:59.000Z

91

Monte Carlo simulation in financial engineering  

Science Conference Proceedings (OSTI)

This paper reviews the use of Monte Carlo simulation in the field of financial engineering. It focuses on several interesting topics and introduces their recent development, including path generation, pricing American-style derivatives, evaluating Greeks ...

Nan Chen; L. Jeff Hong

2007-12-01T23:59:59.000Z

92

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

93

Spot Distillate & Crude Oil Prices - U.S. Energy Information ...  

U.S. Energy Information Administration (EIA)

WTI crude oil price rose about $17 per barrel or 40 cents per gallon from its low point in mid ... New York Harbor spot heating oil had risen about 42 cents ...

94

Figure 88. Annual average Henry Hub spot prices for natural ...  

U.S. Energy Information Administration (EIA)

Sheet3 Sheet2 Sheet1 Figure 88. Annual average Henry Hub spot prices for natural gas in five cases, 1990-2040 (2011 dollars per million Btu) Reference

95

Current Natural Gas Spot Prices:. Well Above the Recent Price ...  

U.S. Energy Information Administration (EIA)

The surge in spot prices at the Henry Hub since April has taken prices well above a typical range for 1998-1999 (in this context, defined as the average, +/- 2 ...

96

Natural Gas Spot Prices: Base Case and 95% Confidence Interval  

U.S. Energy Information Administration (EIA)

Spot prices at the Henry Hub traded at a midpoint of $6.91 per MMBtu on Wednesday. This is the first time the price has been below $7.00 since December 1, ...

97

Tight Product Balance Pushes Up Product Spread (Spot Product...  

Gasoline and Diesel Fuel Update (EIA)

1 Notes: To reinforce the impact that inventory levels (I.e., tight markets) have on price, note the variation in spot gasoline prices relative to crude oil prices, as shown by the...

98

page 7 : Turing's Spot-Generation System - CECM  

E-Print Network (OSTI)

System for generating spots proposed by Turing: $\\bigtriangleup a_{ij} = s(16 - a_ {ij} $\\bigtriangleup b_{ij} = s(a_{ij}b_{. where s is the source density constant.

99

Unsupervised spoken keyword spotting and learning of acoustically meaningful units  

E-Print Network (OSTI)

The problem of keyword spotting in audio data has been explored for many years. Typically researchers use supervised methods to train statistical models to detect keyword instances. However, such supervised methods require ...

Zhang, Yaodong, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

100

Spots, plages, and flares on lambda Andromedae and II Pegasi  

E-Print Network (OSTI)

We present the results of a contemporaneous photometric and spectroscopic monitoring of lambda And and II Peg aimed at investigating the behavior of surface inhomogeneities in the atmospheres of these active stars which have nearly the same temperature but different gravity. The light curves and the modulation of the surface temperature, as recovered from LDRs, are used to map the photospheric spots, while the H-alpha emission has been used as an indicator of chromospheric inhomogeneities. The spot temperatures and sizes were derived from a spot model applied to the contemporaneous light and temperature curves. We find larger and cooler spots on II Peg (T_sp ~ 3600 K) compared to lambda And (T_sp ~ 3900 K); this could be the result of both the different gravity and the higher activity level of the former. Moreover, we find a clear anti-correlation between the H-alpha emission and the photospheric diagnostics. We have also detected a modulation of the intensity of the HeI D_3 line with the star rotation. A rough reconstruction of the 3D structure of their atmospheres has been also performed by applying a spot/plage model to the light and temperature curves and to the H-alpha flux modulation. A close spatial association of photospheric and chromospheric active regions has been found in both stars. Larger and cooler spots have been found on II Peg, the system with the active component of higher gravity and higher activity level. The area ratio of plages to spots seems to decrease when the spots get bigger. Moreover, with the present and literature data, a correlation between the temperature difference Delta_T = T_ph - T_sp and the surface gravity has been also suggested. In addition, a strong flare affecting the H-alpha, the HeI D_3, and the cores of NaI D_1,2 lines has been observed on II Peg.

A. Frasca; K. Biazzo; G. Tas; S. Evren; A. C. Lanzafame

2007-11-21T23:59:59.000Z

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

A measurement concept for hot-spot BRDFs from space  

DOE Green Energy (OSTI)

Several concepts for canopy hot-spot measurements from space have been investigated. The most promising involves active illumination and bistatic detection that would allow hot-spot angular distribution (BRDF) measurements from space in a search-light mode. The concept includes a pointable illumination source, such as a laser operating at an atmospheric window wavelength, coupled with a number of high spatial-resolution detectors that are clustered around the illumination source in space, receiving photons nearly coaxial with the reto-reflection direction. Microwave control and command among the satellite cluster would allow orienting the direction of the laser beam as well as the focusing detectors simultaneously so that the coupled system can function like a search light with almost unlimited pointing capabilities. The concept is called the Hot-Spot Search-Light (HSSL) satellite. A nominal satellite altitude of 600 km will allow hot-spot BRDF measurements out to about 18 degrees phase angle. The distributed are taking radiometric measurements of the intensity wings of the hot-spot angular distribution without the need for complex imaging detectors. The system can be operated at night for increased signal-to-noise ratio. This way the hot-spot angular signatures can be quantified and parameterized in sufficient detail to extract the biophysical information content of plant architectures.

Gerstl, S.A.W.

1996-09-01T23:59:59.000Z

102

Friction Stir Spot Welding of DP780 Carbon Steel  

Science Conference Proceedings (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

103

Bright Green Spot: Fort Worth Library | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Bright Green Spot: Fort Worth Library 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 energy savings by cutting down consumption. Using an Energy Efficiency and Conservation Block Grant from the Recovery Act, the city was able to have the building retrofitted and install a building management system. The system allows library staff to control the indoor climate of the library from one location to reduce operating costs of the facility. Addthis Related Articles Captured data from the monitoring system at the public library shows that energy usage was highest at 10:30a.m., a time when a number of patrons in the library would be using computers and lighting. | Photo courtesy of Texas Institute for Sustainable Technology Research

104

The Rational Hybrid Monte Carlo Algorithm  

E-Print Network (OSTI)

The past few years have seen considerable progress in algorithmic development for the generation of gauge fields including the effects of dynamical fermions. The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is performed using a rational approximation in place the usual inverse quark matrix kernel is one of these developments. This algorithm has been found to be extremely beneficial in many areas of lattice QCD (chiral fermions, finite temperature, Wilson fermions etc.). We review the algorithm and some of these benefits, and we compare against other recent algorithm developements. We conclude with an update of the Berlin wall plot comparing costs of all popular fermion formulations.

M. A. Clark

2006-10-06T23:59:59.000Z

105

Methodology for Managing the Handling and Combustion of Spot Coal  

Science Conference Proceedings (OSTI)

Fuel purchases can constitute 80 percent of generation costs for a coal-fired power plant. Therefore, reducing fuel costs is often a key strategy for reducing generation costs. Power producers have found the spot coal market to be a viable option for filling the gaps in a plant's coal supply portfolio. On average, over the last 10 years, approximately 33 percent of the coal purchased was in the form of spot contracts. While lower quality, cheaper fuels reduce fuel costs; unit capacity, availability, and ...

2007-12-20T23:59:59.000Z

106

Monte Carlo Renormalization Group: a review  

Science Conference Proceedings (OSTI)

The logic and the methods of Monte Carlo Renormalization Group (MCRG) are reviewed. A status report of results for 4-dimensional lattice gauge theories derived using MCRG is presented. Existing methods for calculating the improved action are reviewed and evaluated. The Gupta-Cordery improved MCRG method is described and compared with the standard one. 71 refs., 8 figs.

Gupta, R.

1985-01-01T23:59:59.000Z

107

Relevance of accurate Monte Carlo modeling in nuclear medical imaging  

Science Conference Proceedings (OSTI)

Monte Carlo techniques have become popular in different areas of medical physics with advantage of powerful computing systems. In particular

Habib Zaidi

1999-01-01T23:59:59.000Z

108

Tenneco upgrades natural gasoline  

SciTech Connect

Tenneco Oil Co. recently completed a natural gasoline upgrading project at its LaPorte, Tex., facility. The project was started in October 1985. The purpose was to fractionate natural gasoline and isomerize the n-pentane component. Three factors made this a particularly attractive project for the LaPorte complex: 1. The phase down of lead in gasoline made further processing of natural gasoline desirable. 2. Idle equipment and trained personnel were available at the plant as a result of a switch of Tenneco's natural gas liquids (NGL) fractionation to its Mont Belvieu, Tex., facility. 3. The plant interconnects with Houston's local markets. It has pipelines to Mont Belvieu, Texas City, and plants along the Houston Ship Channel, as well as truck, tank car, and barge-loading facilities. Here are the details on the operation of the facilities, the changes which were required to enable the plant to operate successfully, and how this conversion was completed in a timely fashion.

O'Gorman, E.K.

1986-08-01T23:59:59.000Z

109

Jupiter's Great Red Spot as a Shallow Water System  

Science Conference Proceedings (OSTI)

Most current models of Jupiter's Great Red Spot (GRS) are cast in terms of a two-layer model, where a thin upper weather layer, which contains the vortex, overlies a much deeper layer, which is meant to represent the neutrally stratified deep ...

Timothy E. Dowling; Andrew P. Ingersoll

1989-11-01T23:59:59.000Z

110

Simulations of Electron Transport in Laser Hot Spots  

Science Conference Proceedings (OSTI)

Simulations of electron transport are carried out by solving the Fokker-Planck equation in the diffusive approximation. The system of a single laser hot spot, with open boundary conditions, is systematically studied by performing a scan over a wide range of the two relevant parameters: (1) Ratio of the stopping length over the width of the hot spot. (2) Relative importance of the heating through inverse Bremsstrahlung compared to the thermalization through self-collisions. As for uniform illumination [J.P. Matte et al., Plasma Phys. Controlled Fusion 30 (1988) 1665], the bulk of the velocity distribution functions (VDFs) present a super-Gaussian dependence. However, as a result of spatial transport, the tails are observed to be well represented by a Maxwellian. A similar dependence of the distributions is also found for multiple hot spot systems. For its relevance with respect to stimulated Raman scattering, the linear Landau damping of the electron plasma wave is estimated for such VD Fs. Finally, the nonlinear Fokker-Planck simulations of the single laser hot spot system are also compared to the results obtained with the linear non-local hydrodynamic approach [A.V. Brantov et al., Phys. Plasmas 5 (1998) 2742], thus providing a quantitative limit to the latter method: The hydrodynamic approach presents more than 10% inaccuracy in the presence of temperature variations of the order delta T/T greater than or equal to 1%, and similar levels of deformation of the Gaussian shape of the Maxwellian background.

S. Brunner; E. Valeo

2001-08-30T23:59:59.000Z

111

IC defect sensitivity for footprint-type spot defects  

Science Conference Proceedings (OSTI)

While it is important to exhaustively verify IC designs for their functional performance, it is equally important to verify their robustness against spot defects, that is, to foresee what will happen to the design when it is exposed to defect conditions ...

J. Pineda de Gyvez; C. Di

2006-11-01T23:59:59.000Z

112

Condensed history Monte Carlo methods for photon transport problems  

Science Conference Proceedings (OSTI)

We study methods for accelerating Monte Carlo simulations that retain most of the accuracy of conventional Monte Carlo algorithms. These methods - called Condensed History (CH) methods - have been very successfully used to model the transport of ionizing ... Keywords: Condensed history models, Monte Carlo methods, Radiative transport equation

Katherine Bhan; Jerome Spanier

2007-08-01T23:59:59.000Z

113

QWalk: A quantum Monte Carlo program for electronic structure  

Science Conference Proceedings (OSTI)

We describe QWalk, a new computational package capable of performing quantum Monte Carlo electronic structure calculations for molecules and solids with many electrons. We describe the structure of the program and its implementation of quantum Monte ... Keywords: Monte Carlo, Quantum mechanics, Stochastic methods

Lucas K. Wagner; Michal Bajdich; Lubos Mitas

2009-05-01T23:59:59.000Z

114

Solving Systems of Linear Equations with Relaxed Monte Carlo Method  

Science Conference Proceedings (OSTI)

The problem of solving systems of linear algebraic equations by parallel Monte Carlo numerical methods is considered. A parallel Monte Carlo method with relaxation is presented. This is a report of a research in progress, showing the effectiveness of ... Keywords: Monte Carlo method, linear solver, parallel algorithms, systems of linear algebraic equations

Chih Jeng Kenneth Tan

2002-05-01T23:59:59.000Z

115

Mont Alto Borough | Open Energy Information  

Open Energy Info (EERE)

Alto Borough Alto Borough Jump to: navigation, search Name Mont Alto Borough Place Pennsylvania Utility Id 12817 Utility Location Yes Ownership M NERC Location RFC NERC RFC Yes Activity Buying Transmission Yes Activity Distribution Yes References EIA Form EIA-861 Final Data File for 2010 - File1_a[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Utility Rate Schedules Grid-background.png Commercial Commercial Residential Residential Average Rates Residential: $0.1460/kWh Commercial: $0.0899/kWh Industrial: $0.1480/kWh References ↑ "EIA Form EIA-861 Final Data File for 2010 - File1_a" Retrieved from "http://en.openei.org/w/index.php?title=Mont_Alto_Borough&oldid=411118"

116

Monte Carlo Simulation for Particle Detectors  

E-Print Network (OSTI)

Monte Carlo simulation is an essential component of experimental particle physics in all the phases of its life-cycle: the investigation of the physics reach of detector concepts, the design of facilities and detectors, the development and optimization of data reconstruction software, the data analysis for the production of physics results. This note briefly outlines some research topics related to Monte Carlo simulation, that are relevant to future experimental perspectives in particle physics. The focus is on physics aspects: conceptual progress beyond current particle transport schemes, the incorporation of materials science knowledge relevant to novel detection technologies, functionality to model radiation damage, the capability for multi-scale simulation, quantitative validation and uncertainty quantification to determine the predictive power of simulation. The R&D on simulation for future detectors would profit from cooperation within various components of the particle physics community, and synerg...

Pia, Maria Grazia

2012-01-01T23:59:59.000Z

117

Status of Monte Carlo at Los Alamos  

SciTech Connect

At Los Alamos the early work of Fermi, von Neumann, and Ulam has been developed and supplemented by many followers, notably Cashwell and Everett, and the main product today is the continuous-energy, general-purpose, generalized-geometry, time-dependent, coupled neutron-photon transport code called MCNP. The Los Alamos Monte Carlo research and development effort is concentrated in Group X-6. MCNP treats an arbitrary three-dimensional configuration of arbitrary materials in geometric cells bounded by first- and second-degree surfaces and some fourth-degree surfaces (elliptical tori). Monte Carlo has evolved into perhaps the main method for radiation transport calculations at Los Alamos. MCNP is used in every technical division at the Laboratory by over 130 users about 600 times a month accounting for nearly 200 hours of CDC-7600 time.

Thompson, W.L.; Cashwell, E.D.

1980-01-01T23:59:59.000Z

118

Storm Spotting and Public Awareness since the First Tornado Forecasts of 1948  

Science Conference Proceedings (OSTI)

The history of storm spotting and public awareness of the tornado threat is reviewed. It is shown that a downward trend in fatalities apparently began after the famous “Tri-State” tornado of 1925. Storm spotting’s history begins in World War II ...

Charles A. Doswell III; Alan R. Moller; Harold E. Brooks

1999-08-01T23:59:59.000Z

119

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

120

Forecasting Crude Oil Spot Price Using OECD Petroleum Inventory  

Gasoline and Diesel Fuel Update (EIA)

Forecasting Forecasting Crude Oil Spot Price Using OECD Petroleum Inventory Levels MICHAEL YE, ∗ JOHN ZYREN, ∗∗ AND JOANNE SHORE ∗∗ Abstract This paper presents a short-term monthly forecasting model of West Texas Intermedi- ate crude oil spot price using OECD petroleum inventory levels. Theoretically, petroleum inventory levels are a measure of the balance, or imbalance, between petroleum production and demand, and thus provide a good market barometer of crude oil price change. Based on an understanding of petroleum market fundamentals and observed market behavior during the post-Gulf War period, the model was developed with the objectives of being both simple and practical, with required data readily available. As a result, the model is useful to industry and government decision-makers in forecasting price and investigat- ing the impacts of changes on price, should inventories,

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

Tight Product Balance Pushes Up Product Spread (Spot Product - Crude  

Gasoline and Diesel Fuel Update (EIA)

5 5 Notes: Gasoline inventories indicate how tight the gasoline product market is in any one region. When the gasoline market is tight, it affects the portion of gasoline price is the spread between spot product price and crude oil price. Note that in late 1998-and early 1999 spreads were very small when inventories were quite high. Contrast summers of 1998 or 1999 with summer 2000. Last summer's tight markets, resulting low stocks and transition to Phase 2 RFG added price pressure over and above the already high crude price pressure on gasoline -- particularly in the Midwest. As we ended last winter, gasoline inventories were low, and the spread between spot prices and crude oil were higher than typical as a result. Inventories stayed well below average and the spread during the

122

Joint Modelling of Gas and Electricity spot prices  

E-Print Network (OSTI)

The recent liberalization of the electricity and gas markets has resulted in the growth of energy exchanges and modelling problems. In this paper, we modelize jointly gas and electricity spot prices using a mean-reverting model which fits the correlations structures for the two commodities. The dynamics are based on Ornstein processes with parameterized diffusion coefficients. Moreover, using the empirical distributions of the spot prices, we derive a class of such parameterized diffusions which captures the most salient statistical properties: stationarity, spikes and heavy-tailed distributions. The associated calibration procedure is based on standard and efficient statistical tools. We calibrate the model on French for electricity and on UK market for gas, and then simulate some trajectories which reproduce well the observed prices behavior. Finally, we illustrate the importance of the correlation structure and of the presence of spikes by measuring the risk on a power plant portfolio.

Frikha, Noufel

2009-01-01T23:59:59.000Z

123

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

124

Fission Matrix Capability for MCNP Monte Carlo  

Science Conference Proceedings (OSTI)

In a Monte Carlo criticality calculation, before the tallying of quantities can begin, a converged fission source (the fundamental eigenvector of the fission kernel) is required. Tallies of interest may include powers, absorption rates, leakage rates, or the multiplication factor (the fundamental eigenvalue of the fission kernel, k{sub eff}). Just as in the power iteration method of linear algebra, if the dominance ratio (the ratio of the first and zeroth eigenvalues) is high, many iterations of neutron history simulations are required to isolate the fundamental mode of the problem. Optically large systems have large dominance ratios, and systems containing poor neutron communication between regions are also slow to converge. The fission matrix method, implemented into MCNP[1], addresses these problems. When Monte Carlo random walk from a source is executed, the fission kernel is stochastically applied to the source. Random numbers are used for: distances to collision, reaction types, scattering physics, fission reactions, etc. This method is used because the fission kernel is a complex, 7-dimensional operator that is not explicitly known. Deterministic methods use approximations/discretization in energy, space, and direction to the kernel. Consequently, they are faster. Monte Carlo directly simulates the physics, which necessitates the use of random sampling. Because of this statistical noise, common convergence acceleration methods used in deterministic methods do not work. In the fission matrix method, we are using the random walk information not only to build the next-iteration fission source, but also a spatially-averaged fission kernel. Just like in deterministic methods, this involves approximation and discretization. The approximation is the tallying of the spatially-discretized fission kernel with an incorrect fission source. We address this by making the spatial mesh fine enough that this error is negligible. As a consequence of discretization we get a spatially low-order kernel, the fundamental eigenvector of which should converge faster than that of continuous kernel. We can then redistribute the fission bank to match the fundamental fission matrix eigenvector, effectively eliminating all higher modes. For all computations here biasing is not used, with the intention of comparing the unaltered, conventional Monte Carlo process with the fission matrix results. The source convergence of standard Monte Carlo criticality calculations are, to some extent, always subject to the characteristics of the problem. This method seeks to partially eliminate this problem-dependence by directly calculating the spatial coupling. The primary cost of this, which has prevented widespread use since its inception [2,3,4], is the extra storage required. To account for the coupling of all N spatial regions to every other region requires storing N{sup 2} values. For realistic problems, where a fine resolution is required for the suppression of discretization error, the storage becomes inordinate. Two factors lead to a renewed interest here: the larger memory available on modern computers and the development of a better storage scheme based on physical intuition. When the distance between source and fission events is short compared with the size of the entire system, saving memory by accounting for only local coupling introduces little extra error. We can gain other information from directly tallying the fission kernel: higher eigenmodes and eigenvalues. Conventional Monte Carlo cannot calculate this data - here we have a way to get new information for multiplying systems. In Ref. [5], higher mode eigenfunctions are analyzed for a three-region 1-dimensional problem and 2-dimensional homogenous problem. We analyze higher modes for more realistic problems. There is also the question of practical use of this information; here we examine a way of using eigenmode information to address the negative confidence interval bias due to inter-cycle correlation. We apply this method mainly to four problems: 2D pressurized water reactor (PWR) [6],

Carney, Sean E. [Los Alamos National Laboratory; Brown, Forrest B. [Los Alamos National Laboratory; Kiedrowski, Brian C. [Los Alamos National Laboratory; Martin, William R. [Los Alamos National Laboratory

2012-09-05T23:59:59.000Z

125

Fission Matrix Capability for MCNP Monte Carlo  

SciTech Connect

In a Monte Carlo criticality calculation, before the tallying of quantities can begin, a converged fission source (the fundamental eigenvector of the fission kernel) is required. Tallies of interest may include powers, absorption rates, leakage rates, or the multiplication factor (the fundamental eigenvalue of the fission kernel, k{sub eff}). Just as in the power iteration method of linear algebra, if the dominance ratio (the ratio of the first and zeroth eigenvalues) is high, many iterations of neutron history simulations are required to isolate the fundamental mode of the problem. Optically large systems have large dominance ratios, and systems containing poor neutron communication between regions are also slow to converge. The fission matrix method, implemented into MCNP[1], addresses these problems. When Monte Carlo random walk from a source is executed, the fission kernel is stochastically applied to the source. Random numbers are used for: distances to collision, reaction types, scattering physics, fission reactions, etc. This method is used because the fission kernel is a complex, 7-dimensional operator that is not explicitly known. Deterministic methods use approximations/discretization in energy, space, and direction to the kernel. Consequently, they are faster. Monte Carlo directly simulates the physics, which necessitates the use of random sampling. Because of this statistical noise, common convergence acceleration methods used in deterministic methods do not work. In the fission matrix method, we are using the random walk information not only to build the next-iteration fission source, but also a spatially-averaged fission kernel. Just like in deterministic methods, this involves approximation and discretization. The approximation is the tallying of the spatially-discretized fission kernel with an incorrect fission source. We address this by making the spatial mesh fine enough that this error is negligible. As a consequence of discretization we get a spatially low-order kernel, the fundamental eigenvector of which should converge faster than that of continuous kernel. We can then redistribute the fission bank to match the fundamental fission matrix eigenvector, effectively eliminating all higher modes. For all computations here biasing is not used, with the intention of comparing the unaltered, conventional Monte Carlo process with the fission matrix results. The source convergence of standard Monte Carlo criticality calculations are, to some extent, always subject to the characteristics of the problem. This method seeks to partially eliminate this problem-dependence by directly calculating the spatial coupling. The primary cost of this, which has prevented widespread use since its inception [2,3,4], is the extra storage required. To account for the coupling of all N spatial regions to every other region requires storing N{sup 2} values. For realistic problems, where a fine resolution is required for the suppression of discretization error, the storage becomes inordinate. Two factors lead to a renewed interest here: the larger memory available on modern computers and the development of a better storage scheme based on physical intuition. When the distance between source and fission events is short compared with the size of the entire system, saving memory by accounting for only local coupling introduces little extra error. We can gain other information from directly tallying the fission kernel: higher eigenmodes and eigenvalues. Conventional Monte Carlo cannot calculate this data - here we have a way to get new information for multiplying systems. In Ref. [5], higher mode eigenfunctions are analyzed for a three-region 1-dimensional problem and 2-dimensional homogenous problem. We analyze higher modes for more realistic problems. There is also the question of practical use of this information; here we examine a way of using eigenmode information to address the negative confidence interval bias due to inter-cycle correlation. We apply this method mainly to four problems: 2D pressurized water reactor (PWR) [6],

Carney, Sean E. [Los Alamos National Laboratory; Brown, Forrest B. [Los Alamos National Laboratory; Kiedrowski, Brian C. [Los Alamos National Laboratory; Martin, William R. [Los Alamos National Laboratory

2012-09-05T23:59:59.000Z

126

Monte Carlo Particle Transport: Algorithm and Performance Overview  

National Nuclear Security Administration (NNSA)

Monte Carlo Particle Transport: Monte Carlo Particle Transport: Algorithm and Performance Overview N. A. Gentile, R. J. Procassini and H. A. Scott Lawrence Livermore National Laboratory, Livermore, California, 94551 Monte Carlo methods are frequently used for neutron and radiation trans- port. These methods have several advantages, such as relative ease of programming and dealing with complex meshes. Disadvantages include long run times and statistical noise. Monte Carlo photon transport calcu- lations also often suffer from inaccuracies in matter temperature due to the lack of implicitness. In this paper we discuss the Monte Carlo algo- rithm as it is applied to neutron and photon transport, detail the differ- ences between neutron and photon Monte Carlo, and give an overview of the ways the numerical method has been modified to deal with issues that

127

Quantum Monte Carlo for vibrating molecules  

SciTech Connect

Quantum Monte Carlo (QMC) has successfully computed the total electronic energies of atoms and molecules. The main goal of this work is to use correlation function quantum Monte Carlo (CFQMC) to compute the vibrational state energies of molecules given a potential energy surface (PES). In CFQMC, an ensemble of random walkers simulate the diffusion and branching processes of the imaginary-time time dependent Schroedinger equation in order to evaluate the matrix elements. The program QMCVIB was written to perform multi-state VMC and CFQMC calculations and employed for several calculations of the H{sub 2}O and C{sub 3} vibrational states, using 7 PES`s, 3 trial wavefunction forms, two methods of non-linear basis function parameter optimization, and on both serial and parallel computers. In order to construct accurate trial wavefunctions different wavefunctions forms were required for H{sub 2}O and C{sub 3}. In order to construct accurate trial wavefunctions for C{sub 3}, the non-linear parameters were optimized with respect to the sum of the energies of several low-lying vibrational states. In order to stabilize the statistical error estimates for C{sub 3} the Monte Carlo data was collected into blocks. Accurate vibrational state energies were computed using both serial and parallel QMCVIB programs. Comparison of vibrational state energies computed from the three C{sub 3} PES`s suggested that a non-linear equilibrium geometry PES is the most accurate and that discrete potential representations may be used to conveniently determine vibrational state energies.

Brown, W.R. [Univ. of California, Berkeley, CA (United States). Chemistry Dept.]|[Lawrence Berkeley National Lab., CA (United States). Chemical Sciences Div.

1996-08-01T23:59:59.000Z

128

Exascale Monte Carlo R&D  

Science Conference Proceedings (OSTI)

Overview of this presentation is (1) Exascale computing - different technologies, getting there; (2) high-performance proof-of-concept MCMini - features and results; and (3) OpenCL toolkit - Oatmeal (OpenCL Automatic Memory Allocation Library) - purpose and features. Despite driver issues, OpenCL seems like a good, hardware agnostic tool. MCMini demonstrates the possibility for GPGPU-based Monte Carlo methods - it shows great scaling for HPC application and algorithmic equivalence. Oatmeal provides a flexible framework to aid in the development of scientific OpenCL codes.

Marcus, Ryan C. [Los Alamos National Laboratory

2012-07-24T23:59:59.000Z

129

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

2009-03-17T23:59:59.000Z

130

Discrete diffusion Monte Carlo for frequency-dependent radiative transfer  

SciTech Connect

Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Implicit Monte Carlo radiative-transfer simulations. In this paper, we develop an extension of DDMC for frequency-dependent radiative transfer. We base our new DDMC method on a frequency-integrated diffusion equation for frequencies below a specified threshold. Above this threshold we employ standard Monte Carlo. With a frequency-dependent test problem, we confirm the increased efficiency of our new DDMC technique.

Densmore, Jeffrey D [Los Alamos National Laboratory; Kelly, Thompson G [Los Alamos National Laboratory; Urbatish, Todd J [Los Alamos National Laboratory

2010-11-17T23:59:59.000Z

131

Numerical study of error propagation in Monte Carlo depletion simulations.  

E-Print Network (OSTI)

??Improving computer technology and the desire to more accurately model the heterogeneity of the nuclear reactor environment have made the use of Monte Carlo depletion… (more)

Wyant, Timothy Joseph

2012-01-01T23:59:59.000Z

132

HILO: Quasi Diffusion Accelerated Monte Carlo on Hybrid Architectures  

NLE Websites -- All DOE Office Websites (Extended Search)

HILO: Quasi Diffusion Accelerated Monte Carlo on Hybrid Architectures The Boltzmann transport equation provides high fidelity simulation of a diverse range of kinetic systems....

133

A Kinetic Monte Carlo Model for Material Aging: Simulations of ...  

Science Conference Proceedings (OSTI)

In this paper, we develop a kinetic Monte Carlo framework aiming at ... A Controlled Stress Energy Minimization Method for Coarse-grained Atomistic Simulation.

134

Visualizing Quantum Monte Carlo Study of Photoprotection via...  

NLE Websites -- All DOE Office Websites (Extended Search)

Photoprotection via Carotenoids in Photosynthetic Centers Quantum Monte Carlo Study of Photoprotection via Carotenoids in Photosynthetic Centers photosynthesisimage30y2004.jpg The...

135

Quantum Monte Carlo for atoms and molecules  

DOE Green Energy (OSTI)

The diffusion quantum Monte Carlo with fixed nodes (QMC) approach has been employed in studying energy-eigenstates for 1--4 electron systems. Previous work employing the diffusion QMC technique yielded energies of high quality for H{sub 2}, LiH, Li{sub 2}, and H{sub 2}O. Here, the range of calculations with this new approach has been extended to include additional first-row atoms and molecules. In addition, improvements in the previously computed fixed-node energies of LiH, Li{sub 2}, and H{sub 2}O have been obtained using more accurate trial functions. All computations were performed within, but are not limited to, the Born-Oppenheimer approximation. In our computations, the effects of variation of Monte Carlo parameters on the QMC solution of the Schroedinger equation were studied extensively. These parameters include the time step, renormalization time and nodal structure. These studies have been very useful in determining which choices of such parameters will yield accurate QMC energies most efficiently. Generally, very accurate energies (90--100% of the correlation energy is obtained) have been computed with single-determinant trail functions multiplied by simple correlation functions. Improvements in accuracy should be readily obtained using more complex trial functions.

Barnett, R.N.

1989-11-01T23:59:59.000Z

136

THE MCNPX MONTE CARLO RADIATION TRANSPORT CODE  

SciTech Connect

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

137

Energy Monte Carlo (EMCEE) | Open Energy Information  

Open Energy Info (EERE)

Energy Monte Carlo (EMCEE) Energy Monte Carlo (EMCEE) Jump to: navigation, search Tool Summary LAUNCH TOOL Name: EMCEE and Emc2 Agency/Company /Organization: United States Geological Survey Sector: Energy Focus Area: Non-renewable Energy Topics: Resource assessment Resource Type: Software/modeling tools User Interface: Spreadsheet Website: pubs.usgs.gov/pp/pp1713/26/ Country: United States Cost: Free Northern America Coordinates: 37.09024°, -95.712891° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.09024,"lon":-95.712891,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

138

Quantum Monte Carlo Endstation for Petascale Computing  

SciTech Connect

NCSU research group has been focused on accomplising the key goals of this initiative: establishing new generation of quantum Monte Carlo (QMC) computational tools as a part of Endstation petaflop initiative for use at the DOE ORNL computational facilities and for use by computational electronic structure community at large; carrying out high accuracy quantum Monte Carlo demonstration projects in application of these tools to the forefront electronic structure problems in molecular and solid systems; expanding the impact of QMC methods and approaches; explaining and enhancing the impact of these advanced computational approaches. In particular, we have developed quantum Monte Carlo code (QWalk, www.qwalk.org) which was significantly expanded and optimized using funds from this support and at present became an actively used tool in the petascale regime by ORNL researchers and beyond. These developments have been built upon efforts undertaken by the PI's group and collaborators over the period of the last decade. The code was optimized and tested extensively on a number of parallel architectures including petaflop ORNL Jaguar machine. We have developed and redesigned a number of code modules such as evaluation of wave functions and orbitals, calculations of pfaffians and introduction of backflow coordinates together with overall organization of the code and random walker distribution over multicore architectures. We have addressed several bottlenecks such as load balancing and verified efficiency and accuracy of the calculations with the other groups of the Endstation team. The QWalk package contains about 50,000 lines of high quality object-oriented C++ and includes also interfaces to data files from other conventional electronic structure codes such as Gamess, Gaussian, Crystal and others. This grant supported PI for one month during summers, a full-time postdoc and partially three graduate students over the period of the grant duration, it has resulted in 13 published papers, 15 invited talks and lectures nationally and internationally. My former graduate student and postdoc Dr. Michal Bajdich, who was supported byt this grant, is currently a postdoc with ORNL in the group of Dr. F. Reboredo and Dr. P. Kent and is using the developed tools in a number of DOE projects. The QWalk package has become a truly important research tool used by the electronic structure community and has attracted several new developers in other research groups. Our tools use several types of correlated wavefunction approaches, variational, diffusion and reptation methods, large-scale optimization methods for wavefunctions and enables to calculate energy differences such as cohesion, electronic gaps, but also densities and other properties, using multiple runs one can obtain equations of state for given structures and beyond. Our codes use efficient numerical and Monte Carlo strategies (high accuracy numerical orbitals, multi-reference wave functions, highly accurate correlation factors, pairing orbitals, force biased and correlated sampling Monte Carlo), are robustly parallelized and enable to run on tens of thousands cores very efficiently. Our demonstration applications were focused on the challenging research problems in several fields of materials science such as transition metal solids. We note that our study of FeO solid was the first QMC calculation of transition metal oxides at high pressures.

Lubos Mitas

2011-01-26T23:59:59.000Z

139

Spot Prices for Crude Oil and Petroleum Products  

U.S. Energy Information Administration (EIA) Indexed Site

Spot Prices Spot Prices (Crude Oil in Dollars per Barrel, Products in Dollars per Gallon) Period: Daily Weekly Monthly Annual Download Series History Download Series History Definitions, Sources & Notes Definitions, Sources & Notes Product by Area 12/09/13 12/10/13 12/11/13 12/12/13 12/13/13 12/16/13 View History Crude Oil WTI - Cushing, Oklahoma 97.1 98.32 97.25 97.21 96.27 97.18 1986-2013 Brent - Europe 110.07 108.91 109.47 108.99 108.08 110.3 1987-2013 Conventional Gasoline New York Harbor, Regular 2.677 2.698 2.670 2.643 2.639 2.650 1986-2013 U.S. Gulf Coast, Regular 2.459 2.481 2.429 2.398 2.377 2.422 1986-2013 RBOB Regular Gasoline Los Angeles 2.639 2.661 2.569 2.543 2.514 2.527 2003-2013 No. 2 Heating Oil New York Harbor

140

Homing in on sweet spots in Cretaceous Austin chalk  

SciTech Connect

In discussing the nature and causes of fracturing in the Cretaceous Austin chalk of south central Texas, many geologists and operators involved in horizontal drilling of the chalk consider regional rock stress as the probable main cause of the fractures. If Austin chalk fractures are mainly the result of regional extensional stress without localizing factors, then fractured sweet spots are randomly distributed and successful exploration is more or less a matter of luck, usually dependent upon the coincidental placement of a seismic line. But if local, deep-seated structure or basement topography are the main causes of sweet spots, then a successful exploration method would be to first delineate the basement paleo structure or topography and secondly, place a seismic line to confirm the delineated features. Finding localities of maximum fracturing and production would than be based on scientific logic rather than luck. It is the purpose of this article to present the results of an examination of these alternative causes for the Austin chalk fracturing in the hope of determining the most cost effective exploration method for the fractured chalk reservoir.

Thomas, G.E. (Thomas and Associates, Denver, CO (United States)); Sonnenberg, F.P.

1993-11-29T23:59:59.000Z

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

Diode magnetic-field influence on radiographic spot size  

Science Conference Proceedings (OSTI)

Flash radiography of hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories. The Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos was developed for flash radiography of large hydrodynamic experiments. Two linear induction accelerators (LIAs) produce the bremsstrahlung radiographic source spots for orthogonal views of each experiment ('hydrotest'). The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. For time resolution of the hydrotest dynamics, the 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by slicing them out of a longer pulse that has a 1.6-{micro}s flattop. Both axes now routinely produce radiographic source spot sizes having full-width at half-maximum (FWHM) less than 1 mm. To further improve on the radiographic resolution, one must consider the major factors influencing the spot size: (1) Beam convergence at the final focus; (2) Beam emittance; (3) Beam canonical angular momentum; (4) Beam-motion blur; and (5) Beam-target interactions. Beam emittance growth and motion in the accelerators have been addressed by careful tuning. Defocusing by beam-target interactions has been minimized through tuning of the final focus solenoid for optimum convergence and other means. Finally, the beam canonical angular momentum is minimized by using a 'shielded source' of electrons. An ideal shielded source creates the beam in a region where the axial magnetic field is zero, thus the canonical momentum zero, since the beam is born with no mechanical angular momentum. It then follows from Busch's conservation theorem that the canonical angular momentum is minimized at the target, at least in principal. In the DARHT accelerators, the axial magnetic field at the cathode is minmized by using a 'bucking coil' solenoid with reverse polarity to cancel out whatever solenoidal beam transport field exists there. This is imperfect in practice, because of radial variation of the total field across the cathode surface, solenoid misalignments, and long-term variability of solenoid fields for given currents. Therefore, it is useful to quantify the relative importance of canonical momentum in determining the focal spot, and to establish a systematic methodology for tuning the bucking coils for minimum spot size. That is the purpose of this article. Section II provides a theoretical foundation for understanding the relative importance of the canonical momentum. Section III describes the results of simulations used to quantify beam parameters, including the momentum, for each of the accelerators. Section IV compares the two accelerators, especially with respect to mis-tuned bucking coils. Finally, Section IV concludes with a methodology for optimizing the bucking coil settings.

Ekdahl, Carl A. Jr. [Los Alamos National Laboratory

2012-09-04T23:59:59.000Z

142

Efficient, automated Monte Carlo methods for radiation transport  

Science Conference Proceedings (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 ... Keywords: Computational efficiency, Geometrically convergent Monte Carlo algorithms, Transport equation

Rong Kong; Martin Ambrose; Jerome Spanier

2008-11-01T23:59:59.000Z

143

Adjoint electron-photon transport Monte Carlo calculations with ITS  

Science Conference Proceedings (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

144

Bold diagrammatic Monte Carlo for the resonant Fermi gas  

E-Print Network (OSTI)

We provide a comprehensive description of the Bold Diagrammatic Monte Carlo algorithm for the normal resonant Fermi gas that was briefly reported and used in [Nature Phys. 8, 366 (2012)] and [arXiv:1303.6245]. Details are given on all key aspects of the scheme: diagrammatic framework, Monte Carlo moves, ultraviolet asymptotics, and resummation techniques.

Van Houcke, K; Prokof'ev, N; Svistunov, B

2013-01-01T23:59:59.000Z

145

Quantum Monte Carlo simulations of solids W. M. C. Foulkes  

E-Print Network (OSTI)

Quantum Monte Carlo simulations of solids W. M. C. Foulkes CMTH Group, Department of Physics and fixed-node diffusion quantum Monte Carlo methods and how they may be used to calculate the properties of quantum many-body effects and serve as benchmarks against which other techniques may be compared

Wu, Zhigang

146

Monte Carlo calculations of channeling radiation  

Science Conference Proceedings (OSTI)

Results of classical Monte Carlo calculations are presented for the radiation produced by ultra-relativistic positrons incident in a direction parallel to the (110) plane of Si in the energy range 30 to 100 MeV. The results all show the characteristic CR(channeling radiation) peak in the energy range 20 keV to 100 keV. Plots of the centroid energies, widths, and total yields of the CR peaks as a function of energy show the power law dependences of ..gamma../sup 1/ /sup 5/, ..gamma../sup 1/ /sup 7/, and ..gamma../sup 2/ /sup 5/ respectively. Except for the centroid energies and power-law dependence is only approximate. Agreement with experimental data is good for the centroid energies and only rough for the widths. Adequate experimental data for verifying the yield dependence on ..gamma.. does not yet exist.

Bloom, S.D.; Berman, B.L.; Hamilton, D.C.; Alguard, M.J.; Barrett, J.H.; Datz, S.; Pantell, R.H.; Swent, R.H.

1981-01-01T23:59:59.000Z

147

Hybrid algorithms in quantum Monte Carlo  

SciTech Connect

With advances in algorithms and growing computing powers, quantum Monte Carlo (QMC) methods have become a leading contender for high accuracy calculations for the electronic structure of realistic systems. The performance gain on recent HPC systems is largely driven by increasing parallelism: the number of compute cores of a SMP and the number of SMPs have been going up, as the Top500 list attests. However, the available memory as well as the communication and memory bandwidth per element has not kept pace with the increasing parallelism. This severely limits the applicability of QMC and the problem size it can handle. OpenMP/MPI hybrid programming provides applications with simple but effective solutions to overcome efficiency and scalability bottlenecks on large-scale clusters based on multi/many-core SMPs. We discuss the design and implementation of hybrid methods in QMCPACK and analyze its performance on current HPC platforms characterized by various memory and communication hierarchies.

Esler, Kenneth P [ORNL; Mcminis, Jeremy [University of Illinois, Urbana-Champaign; Morales, Miguel A [Lawrence Livermore National Laboratory (LLNL); Clark, Bryan K. [Princeton University; Shulenburger, Luke [Sandia National Laboratory (SNL); Ceperley, David M [ORNL

2012-01-01T23:59:59.000Z

148

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

2011-05-20T23:59:59.000Z

149

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

2008-12-11T23:59:59.000Z

150

Refill Friction Stir Spot Welding of Aluminum Alloys for Aviation by ...  

Science Conference Proceedings (OSTI)

Refill FSSW process can supersede conventional rivet fastening and resistance spot welding techniques and contribute to weight reduction of structures as well.

151

Empirical Analysis of the Spot Market Implications of Price-Elastic...  

NLE Websites -- All DOE Office Websites (Extended Search)

absence of any significant, rapid demand-side response to the wholesale (or, spot market) price. For a variety of reasons, electricity industries continue to charge most consumers...

152

Empirical Analysis of the Spot Market Implications of Price-Responsive Demand  

E-Print Network (OSTI)

are exposed to real-time electricity prices, they can adjustCustomers Respond to Electricity Price Variability: A Studyhours lowers the electricity spot price and reduces needed

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

2008-01-01T23:59:59.000Z

153

2011 Brief: Henry Hub natural gas spot prices fell about 9% in ...  

U.S. Energy Information Administration (EIA)

Energy Information Administration ... Wholesale spot natural gas prices in most areas of the United States fell slightly in 2011 from the ... In other markets, ...

154

Dose Modeling and Statistical Assessment of Hot Spots for Decommissioning Applications.  

E-Print Network (OSTI)

??A primary goal of this research was to develop a technically defensible approach for modeling the receptor dose due to smaller "hot spots" of residual… (more)

Abelquist, Eric Warner

2008-01-01T23:59:59.000Z

155

Current Natural Gas Spot Prices: Well Above the Recent Price Range  

U.S. Energy Information Administration (EIA)

Current Natural Gas Spot Prices: Well Above the Recent Price Range. Previous slide: Next slide: Back to first slide: ... (generally borne out so far ...

156

U.K., U.S. spot natural gas prices diverging - Today in Energy - U ...  

U.S. Energy Information Administration (EIA)

Two important spot prices for natural gas are the Henry Hub in the United States and the ... a stronger price linkage in Europe between rising crude oil and ...

157

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

158

Monte Carlo Simulation of Joint Transport of Neutrons Monte Carlo Simulation of Joint Transport of Neutrons  

National Nuclear Security Administration (NNSA)

Monte Carlo Simulation of Joint Transport of Neutrons Monte Carlo Simulation of Joint Transport of Neutrons Monte Carlo Simulation of Joint Transport of Neutrons and Photons and Photons Zhitnik Zhitnik A A . . K K . . , , Artemeva Artemeva E.V., E.V., Bakanov Bakanov V.V., V.V., Donskoy Donskoy E.N., E.N., Zalyalov Zalyalov A.N., A.N., Ivanov Ivanov N.V., N.V., Ognev Ognev S.P., S.P., Ronzhin Ronzhin A.B., A.B., Roslov Roslov V.I., V.I., Semenova Semenova T.V. T.V. RFNC-VNIIEF, 607190, Sarov, RFNC-VNIIEF, 607190, Sarov, Nizhni Nizhni Novgorod region Novgorod region The approaches used at VNIIEF to simulate transport of neutrons and photons in standard (with The approaches used at VNIIEF to simulate transport of neutrons and photons in standard (with surface description of region interfaces) and grid geometries are considered in the paper.

159

Quantification of stochastic uncertainty propagation for Monte Carlo depletion methods in reactor analysis.  

E-Print Network (OSTI)

??The Monte Carlo method provides powerful geometric modeling capabilities for large problem domains in 3-D; therefore, the Monte Carlo method is becoming popular for 3-D… (more)

Newell, Quentin Thomas

2011-01-01T23:59:59.000Z

160

Iterative acceleration methods for Monte Carlo and deterministic criticality calculations  

Science Conference Proceedings (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

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

Robert Van Steenwyk Spotted Wing Drosophila (SWD) Recommendations for Sweet Cherry  

E-Print Network (OSTI)

Robert Van Steenwyk Spotted Wing Drosophila (SWD) Recommendations for Sweet of male and female SWD flies in each trap. Male SWD have spots on the tip of the wings and females have produced. The preferred ovipositional color was dark red for Bing fruit and red for Black Tartarian

Hammock, Bruce D.

162

CoCoSpot: Clustering and recognizing botnet command and control channels using traffic analysis  

Science Conference Proceedings (OSTI)

We present CoCoSpot, a novel approach to recognize botnet command and control channels solely based on traffic analysis features, namely carrier protocol distinction, message length sequences and encoding differences. Thus, CoCoSpot can deal with obfuscated ... Keywords: Botnet C&C, Botnet detection, Network security, Traffic analysis

Christian J. Dietrich; Christian Rossow; Norbert Pohlmann

2013-02-01T23:59:59.000Z

163

Model for Thermal Behavior of Shaded Photovoltaic Cells under Hot-Spot Condition  

Science Conference Proceedings (OSTI)

We address the problem of modeling the thermal behavior of photovoltaic (PV) cells that, due to their being exposed to shading, may experience a dramatic temperature increase (a phenomenon referred to as hot-spot) with consequent reduction of the provided ... Keywords: solar cell, hot-spot heating, energy efficiency, reliability

Daniele Giaffreda; Martin Omana; Daniele Rossi; Cecilia Metra

2011-10-01T23:59:59.000Z

164

Parametric and non-parametric approaches in evaluating martingale hypothesis of energy spot markets  

Science Conference Proceedings (OSTI)

This study examined the martingale hypothesis in the spot prices of the petroleum products markets. Under the parametric and non-parametric variance ratio tests, the independent and identically distributed increments and less restrictive martingale increments ... Keywords: Energy spot markets, Financial time series, Martingale process, Structural break, Variance ratio test

Chin Wen Cheong

2011-09-01T23:59:59.000Z

165

Integration of Contracted Renewable Energy and Spot Market Supply to Serve  

E-Print Network (OSTI)

Integration of Contracted Renewable Energy and Spot Market Supply to Serve Flexible Loads Anthony-mail: oren@ieor.berkeley.edu). Abstract: We present a contract for integrating renewable energy supply and electricity spot markets for serving deferrable electric loads in order to mitigate renewable energy

Oren, Shmuel S.

166

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

167

Evaluation of HotSpot, Lawerence Livermore National Laboratory - June 11,  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Evaluation of HotSpot, Lawerence Livermore National Laboratory - Evaluation of HotSpot, Lawerence Livermore National Laboratory - June 11, 2010 Evaluation of HotSpot, Lawerence Livermore National Laboratory - June 11, 2010 June 11, 2010 Letter from Andy Lawrence to John Nasstrom accepting the revised Hotspot In your letter dated April 16, 2010, you summarized the work done by the Lawerence Livermore National Laboratory (LLNL) to meet the Department of Energy's (DOE) recommendations from the 2007, Software Evaluation of HotSpot, and DOE, Safety Software Toolbox Recommendation, for inclusion of V2.07 in the DOE Safety Software Central Registry. Based on this work, you futher requested that HotSpot be included in the DOE Central Registry. Letter from Andy Lawrence to John Nasstrom accepting the revised Hotspot More Documents & Publications

168

Kinetic Monte Carlo simulations of nanocrystalline film deposition  

E-Print Network (OSTI)

A full diffusion kinetic Monte Carlo algorithm is used to model nanocrystalline film deposition, and study the mechanisms of grain nucleation and microstructure formation in such films. The major finding of this work is ...

Ruan, Shiyun

169

Independent Pixel and Monte Carlo Estimates of Stratocumulus Albedo  

Science Conference Proceedings (OSTI)

Monte Carlo radiative transfer methods are employed here to estimate the plane-parallel albedo bias for marine stratocumulus clouds. This is the bias in estimates of the mesoscale-average albedo, which arises from the assumption that cloud liquid ...

Robert F. Cahalan; William Ridgway; Warren J. Wiscombe; Steven Gollmer; Harshvardhan

1994-12-01T23:59:59.000Z

170

Parallel Fission Bank Algorithms in Monte Carlo Criticality Calculations  

E-Print Network (OSTI)

In this work we describe a new method for parallelizing the source iterations in a Monte Carlo criticality calculation. Instead of having one global fission bank that needs to be synchronized, as is traditionally done, our ...

Romano, Paul Kollath

171

Low Dose Radiation Research Program: Monte Carlo Track Structure...  

NLE Websites -- All DOE Office Websites (Extended Search)

Monte Carlo Track Structure Simulations for Low-LET Selected Cell Radiation Studies Walt Wilson Washington State University Tri-Cities Why This Project There are many types of...

172

Bayesian inverse problems with Monte Carlo forward models  

E-Print Network (OSTI)

The full application of Bayesian inference to inverse problems requires exploration of a posterior distribution that typically does not possess a standard form. In this context, Markov chain Monte Carlo (MCMC) methods are ...

Bal, Guillaume

173

Enhancements in Continuous-Energy Monte Carlo Capabilities in SCALE  

SciTech Connect

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

2013-01-01T23:59:59.000Z

174

Microsoft PowerPoint - 13-02 Monts.pptx  

NLE Websites -- All DOE Office Websites (Extended Search)

tankAt-tank Characterization for Closure of Hanford Tanks Ping-Rey Jang, Zhiling Long, O. Perry Norton, Walter P. Okhuysen, and David L. Monts Institute for Clean Energy...

175

Quiet direct simulation Monte-Carlo with random timesteps  

Science Conference Proceedings (OSTI)

Use of a high-order deterministic sampling technique in direct simulation Monte-Carlo (DSMC) simulations eliminates statistical noise and improves computational performance by orders of magnitude. In this paper it is also shown that if a random timestep ... Keywords: 02.50.Ey, 02.70.Tt, 47.11.+j, 52.65.-y, Direct simulation Monte-Carlo, Particle-in-cell methods, Stochastic processess

William Peter

2007-01-01T23:59:59.000Z

176

A hybrid transport-diffusion method for Monte Carlo radiative-transfer simulations  

Science Conference Proceedings (OSTI)

Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Monte Carlo particle-transport simulations in diffusive media. If standard Monte Carlo is used in such media, particle histories will consist of many small steps, resulting ... Keywords: Hybrid transport-diffusion, Monte Carlo, Radiative transfer

Jeffery D. Densmore; Todd J. Urbatsch; Thomas M. Evans; Michael W. Buksas

2007-03-01T23:59:59.000Z

177

High-Performance Quasi-Monte Carlo Financial Simulation: FPGA vs. GPP vs. GPU  

Science Conference Proceedings (OSTI)

Quasi-Monte Carlo simulation is a special Monte Carlo simulation method that uses quasi-random or low-discrepancy numbers as random sample sets. In many applications, this method has proved advantageous compared to the traditional Monte Carlo simulation ... Keywords: CPU, FPGA, GPU, Maxwell, Quasi-Monte Carlo simulations, option pricing

Xiang Tian; Khaled Benkrid

2010-11-01T23:59:59.000Z

178

Quantum Monte Carlo Endstation for Petascale Computing  

Science Conference Proceedings (OSTI)

The major achievements enabled by QMC Endstation grant include * Performance improvement on clusters of x86 multi-core systems, especially on Cray XT systems * New and improved methods for the wavefunction optimizations * New forms of trial wavefunctions * Implementation of the full application on NVIDIA GPUs using CUDA The scaling studies of QMCPACK on large-scale systems show excellent parallel efficiency up to 216K cores on Jaguarpf (Cray XT5). The GPU implementation shows speedups of 10-15x over the CPU implementation on older generation of x86. We have implemented hybrid OpenMP/MPI scheme in QMC to take advantage of multi-core shared memory processors of petascale systems. Our hybrid scheme has several advantages over the standard MPI-only scheme. * Memory optimized: large read-only data to store one-body orbitals and other shared properties to represent the trial wave function and many-body Hamiltonian can be shared among threads, which reduces the memory footprint of a large-scale problem. * Cache optimized: the data associated with an active Walker are in cache during the compute-intensive drift-diffusion process and the operations on an Walker are optimized for cache reuse. Thread-local objects are used to ensure the data affinity to a thread. * Load balanced: Walkers in an ensemble are evenly distributed among threads and MPI tasks. The two-level parallelism reduces the population imbalance among MPI tasks and reduces the number of point-to-point communications of large messages (serialized objects) for the Walker exchange. * Communication optimized: the communication overhead, especially for the collective operations necessary to determine ET and measure the properties of an ensemble, is significantly lowered by using less MPI tasks. The multiple forms of parallelism afforded by QMC algorithms make them ideal candidates for acceleration in the many-core paradigm. We presented the results of our effort to port the QMCPACK simulation code to the NVIDIA CUDA GPU platform. We restructured the CPU algorithms to express additional parallelism, minimize GPU-CPU communication, and efficiently utilize the GPU memory hierarchy. Using mixed precision on GT200 GPUs and MPI for intercommunication and load balancing, we observe typical full-application speedups of approximately 10x to 15x relative to quad-core Xeon CPUs alone, while reproducing the double-precision CPU results within statistical error. We developed an all-electron quantum Monte Carlo (QMC) method for solids that does not rely on pseudopotentials, and used it to construct a primary ultra-high-pressure calibration based on the equation of state of cubic boron nitride. We computed the static contribution to the free energy with the QMC method and obtained the phonon contribution from density functional theory, yielding a high-accuracy calibration up to 900 GPa usable directly in experiment. We computed the anharmonic Raman frequency shift with QMC simulations as a function of pressure and temperature, allowing optical pressure calibration. In contrast to present experimental approaches, small systematic errors in the theoretical EOS do not increase with pressure, and no extrapolation is needed. This all-electron method is applicable to first-row solids, providing a new reference for ab initio calculations of solids and benchmarks for pseudopotential accuracy. We compared experimental and theoretical results on the momentum distribution and the quasiparticle renormalization factor in sodium. From an x-ray Compton-profile measurement of the valence-electron momentum density, we derived its discontinuity at the Fermi wavevector finding an accurate measure of the renormalization factor that we compared with quantum-Monte-Carlo and G0W0 calculations performed both on crystalline sodium and on the homogeneous electron gas. Our calculated results are in good agreement with the experiment. We have been studying the heat of formation for various Kubas complexes of molecular hydrogen on Ti(1,2)ethylene-nH2 using Diffusion Monte Carlo. This work has been started and is o

David Ceperley

2011-03-02T23:59:59.000Z

179

Figure 41. U.S. Brent crude oil and Henry Hub natural gas spot ...  

U.S. Energy Information Administration (EIA)

Sheet3 Sheet2 Sheet1 Figure 41. U.S. Brent crude oil and Henry Hub natural gas spot market prices in three cases, 2005-2040 Natural Gas Crude Oil Reference

180

Spot natural gas prices dipped to two-year low in November ...  

U.S. Energy Information Administration (EIA)

Spot natural gas prices at the Henry Hub in Erath, Louisiana fell to $2.83 per million British thermal units for delivery on November 24, 2011, the lowest price since ...

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

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

E-Print Network (OSTI)

and calibrate our model to the NYMEX Light Sweet Crude Oil spot and futures data, allowing us to extract curves. Adding a perturbation on top of this first order model allows us to correct some

Jaimungal, Sebastian

182

U.S. natural gas spot prices increased during first-half 2013 ...  

U.S. Energy Information Administration (EIA)

Maps by energy source and topic, includes ... Press Releases ... Spot prices on the map reflect averages of daily prices from the first half of 2013, January 1 ...

183

Assessment of Prices of Natural Gas Futures Contracts As A Predictor of Realized Spot Prices, An  

Reports and Publications (EIA)

This article compares realized Henry Hub spot market prices for natural gas during the three most recent winters with futures prices as they evolve from April through the following February, when trading for the March contract ends.

Lejla Alic

2005-10-28T23:59:59.000Z

184

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

E-Print Network (OSTI)

and of the presence of spikes by measuring the risk on a power plant portfolio. Keywords: Electricity markets; spot Abstract The recent liberalization of the electricity and gas markets has resulted in the growth of energy

185

On a euro basis, Brent crude oil spot price surpasses prior ...  

U.S. Energy Information Administration (EIA)

On a euro basis, the spot price for Brent crude oil, a global benchmark, has surpassed its prior record high and set a new record high of 96.53 euros per barrel on ...

186

Figure 21. Annual average spot price for Brent crude oil in three ...  

U.S. Energy Information Administration (EIA)

Sheet3 Sheet2 Sheet1 Figure 21. Annual average spot price for Brent crude oil in three cases, 1990-2040 (2011 dollars per barrel) Reference Low Oil Price

187

Figure 87. Ratio of Brent crude oil price to Henry Hub spot ...  

U.S. Energy Information Administration (EIA)

Sheet3 Sheet2 Sheet1 Figure 87. Ratio of Brent crude oil price to Henry Hub spot natural gas price in energy-equivalent terms, 1990-2040 Ratio Released:April 15, 2013

188

Figure 49. Brent crude oil spot prices in three cases, 1990-2040 ...  

U.S. Energy Information Administration (EIA)

Sheet3 Sheet2 Sheet1 Figure 49. Brent crude oil spot prices in three cases, 1990-2040 (2011 dollars per barrel) Reference High Oil Price Low Oil Price

189

Empirical Analysis of the Spot Market Implications of Price-Responsive Demand  

E-Print Network (OSTI)

used to adjust the real-time price perceived by end-useare exposed to real-time electricity prices, they can adjustof real-time pricing (RTP) on the equilibrium spot price and

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

2008-01-01T23:59:59.000Z

190

Empirical analysis of the spot market implications of price-elastic demand  

E-Print Network (OSTI)

used to adjust the real-time price perceived by end-useare exposed to real-time electricity prices, then they canof real-time pricing on the equilibrium spot price and

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

2004-01-01T23:59:59.000Z

191

DOE Science Showcase - Monte Carlo Methods | OSTI, US Dept of Energy,  

Office of Scientific and Technical Information (OSTI)

Monte Carlo Methods Monte Carlo Methods Monte Carlo calculation methods are algorithms for solving various kinds of computational problems by using (pseudo)random numbers. Developed in the 1940s during the Manhattan Project, the Monte Carlo method signified a radical change in how scientists solved problems. Learn about the ways these methods are used in DOE's research endeavors today in "Monte Carlo Methods" by Dr. William Watson, Physicist, OSTI staff. Effects of static particle dispersions on grain growth are studied using SPPARKS simulations Image credit: Sandia National Laboratory Monte Carlo Results in DOE Databases Lab biophysicist invents improvement to Monte Carlo technique, LLNL News Monte Carlo Benchmark software, ESTSC Improved Monte Carlo Renormalization Group Method, DOE R&D

192

Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots  

DOE Patents (OSTI)

After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a DC power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. A high percentage extraction of proteins is achieved. The extracted proteins can be removed and subjected to partial digestion by trypsin or the like, followed by two-dimensional electrophoresis, resulting in a gel slab having a pattern of peptide gel spots which can be cored out and subjected to electrophoretic extraction to extract individual peptides.

Zhang, Jian-Shi (Shanghai, CN); Giometti, Carol S. (Glenview, IL); Tollaksen, Sandra L. (Montgomery, IL)

1989-01-01T23:59:59.000Z

193

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

Science Conference Proceedings (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

194

Brightness enhancement of plasma ion source by utilizing anode spot for nano applications  

Science Conference Proceedings (OSTI)

Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m{sup 2} SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Yoon-Jae [Samsung Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Park, Man-Jin [Research Institute of Nano Manufacturing System, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Moon, Dae Won [Nanobio Fusion Research Center, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

2012-02-15T23:59:59.000Z

195

USING STAR SPOTS TO MEASURE THE SPIN-ORBIT ALIGNMENT OF TRANSITING PLANETS  

SciTech Connect

Spectroscopic follow-up of dozens of transiting planets has revealed the degree of alignment between the equators of stars and the orbits of the planets they host. Here we determine a method, applicable to spotted stars, that can reveal the same information from the photometric discovery data, with no need for follow-up. A spot model fit to the global light curve, parameterized by the spin orientation of the star, predicts when the planet will transit the spots. Observing several spot crossings during different transits then leads to constraints on the spin-orbit alignment. In cases where stellar spots are small, the stellar inclination, i{sub s} , and hence the true alignment, rather than just the sky projection, can be obtained. This method has become possible with the advent of space telescopes such as CoRoT and Kepler, which photometrically monitor transiting planets over a nearly continuous, long time baseline. We apply our method to CoRoT-2 and find the projected spin-orbit alignment angle, {lambda} = 4.{sup 0}7 {+-} 12.{sup 0}3, in excellent agreement with a previous determination that employed the Rossiter-McLaughlin effect. The large spots of the parent star, CoRoT-2, limit our precision on i{sub s} : 84{sup 0} {+-} 36{sup 0}, where i{sub s} < 90{sup 0}(> 90{sup 0}) indicates that the rotation axis is tilted toward (away from) the line of sight.

Nutzman, Philip A.; Fabrycky, Daniel C.; Fortney, Jonathan J., E-mail: pnutzman@ucolick.org [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States)

2011-10-10T23:59:59.000Z

196

El Monte, California: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

Monte, California: Energy Resources Monte, California: Energy Resources (Redirected from El Monte, CA) Jump to: navigation, search Equivalent URI DBpedia Coordinates 34.0686206°, -118.0275667° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":34.0686206,"lon":-118.0275667,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

197

An Overview of Geometry Representation in Monte Carlo Codes  

National Nuclear Security Administration (NNSA)

Geometry Representation Geometry Representation in Monte Carlo Codes R.P. Kensek, * B.C. Franke, * T.W. Laub * , L.J. Lorence, * M. R. Martin, * S. Warren † * Sandia National Laboratories, P.O. Box 5800, MS 1179, Albuquerque, NM 87185 † Kansas State University, Manhattan, KS 66506 Geometry representations in production Monte Carlo radiation transport codes used for linear-transport simulations are traditionally limited to combinatorial geometry (CG) topologies. While CG representations of input geometries are efficient to query, they are difficult to construct. In the Integrated-TIGER-Series (ITS) Monte Carlo code suite, a new approach for radiation transport geometry engines has been implemented that allows for Computer Aided Design (CAD), facetted approximations, and other geometry types to simultaneously define an input geometry.

198

The Monte Carlo Independent Column Approximation Model Intercomparison  

NLE Websites -- All DOE Office Websites (Extended Search)

The Monte Carlo Independent Column Approximation Model Intercomparison The Monte Carlo Independent Column Approximation Model Intercomparison Project (McMIP) Barker, Howard Meteorological Service of Canada Cole, Jason Meteorological Service of Canada Raisanen, Petri Finnish Meteorological Institute Pincus, Robert NOAA-CIRES Climate Diagnostics Center Morcrette, Jean-Jacques European Centre for Medium-Range Weather Forecasts Li, Jiangnan Canadian Center for Climate Modelling Stephens, Graeme Colorado State University Vaillancourt, Paul Environment Canada Oreopoulos, Lazaros JCET/UMBC and NASA/GSFC Siebesma, Pier KNMI Los, Alexander KNMI Clothiaux, Eugene The Pennsylvania State University Randall, David Colorado State University Iacono, Michael Atmospheric & Environmental Research, Inc. Category: Radiation The Monte Carlo Independent Column Approximation (McICA) method for

199

Monte Carlo Simulations for Mine Detection  

DOE Green Energy (OSTI)

During January, 1998, collaboration between LLNL, UCI and Exdet, Ltd. arranged for the testing and evaluation of a Russian developed antitank mine detection system at the Buried Objects Detection Facility (BODF) located at the Nevada Test Site. BODF is a secured 30-acre facility with approximately 300 live antitank mines that were buried in 1993 and 1994. The burial depths range from a few cm to 15 cm and the various metal- and plastic-case antitank mines each contain 6-12 kg of high explosive. Contractors who have tested their mine detection equipment at BODF include: SAIC, SRI, ERIM, MIT/Lincoln Laboratory and Loral Defense Systems. In addition LLNL researchers have used BODF to test antitank mine detection systems based on: dual-band infrared imaging, hyper-spectral imaging, synthetic aperture impulse radar and micro-impulse radar. In a blind test the Russian operated system obtained the highest score of any technology tested to date at BODF. The system is based on combining information from two separate sensors; one to detect anomalous concentrations of hydrogen and the other to detect if such anomalies also have the correct nitrogen to carbon ratio for high explosives. The detection sensitivity is set by the geometry and type of neutron moderator and filters surrounding the neutron source and detectors. Detection of hydrogen anomalies is a rapid process based on neutron scattering. The handheld instrument on the end of a wand could scan a large area at a rate of 4-5 square meters per minute. Once the hydrogen anomalies were located a second sensor was used to measure the thermal neutron excited gamma-ray spectrum at each hydrogen anomaly to determine whether that location in addition contained high concentrations of nitrogen. The second process was slower, taking up to 5 minutes for each location. The information from both sensors were then examined by the operator and a declaration was made as to whether or not the anomaly was a buried antitank mine. Although the system worked extremely well on all classes of anti-tank mines, the Russian hardware components were inferior to those that are commercially available in the United States, i.e. the NaI(Tl) crystals had significantly higher background levels and poorer resolution than their U.S. counterparts, the electronics appeared to be decades old and the photomultiplier tubes were noisy and lacked gain stabilization circuitry. During the evaluation of this technology, the question that came to mind was: could state-of-the-art sensors and electronics and improved software algorithms lead to a neutron based system that could reliably detect much smaller buried mines; namely antipersonnel mines containing 30-40 grams of high explosive? Our goal in this study was to conduct Monte Carlo simulations to gain better understanding of both phases of the mine detection system and to develop an understanding for the system's overall capabilities and limitations. In addition, we examined possible extensions of this technology to see whether or not state-of-the-art improvements could lead to a reliable anti-personnel mine detection system.

Toor, A.; Marchetti, A.A.

2000-03-14T23:59:59.000Z

200

Weekly Petroleum Status Report  

U.S. Energy Information Administration (EIA) Indexed Site

5 5 Table 12. Spot Prices of Ultra-Low Sulfur Diesel Fuel, Kerosene-Type Jet Fuel, and Propane, 2012 to Present (Dollars per Gallon) Year / Product Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2012 No. 2 Distillate Ultra-Low Sulfur Diesel Fuel New York Harbor ................ 3.080 3.223 3.302 3.242 2.987 2.710 2.921 3.179 3.229 3.236 3.180 3.070 U.S. Gulf Coast ................... 3.034 3.178 3.270 3.217 2.947 2.667 2.879 3.143 3.186 3.157 2.997 2.960 Los Angeles ........................ 3.088 3.242 3.384 3.252 3.007 2.654 2.854 3.225 3.299 3.226 3.071 2.971 Kerosene-Type Jet Fuel U.S. Gulf Coast ..................... 3.087 3.207 3.256 3.226 2.974 2.678 2.892 3.156 3.191 3.111 2.960 2.940 Propane Mont Belvieu ......................... 1.294 1.220 1.261 1.196 0.954 0.788 0.874 0.901 0.910 0.962 0.890 0.797 2013 No. 2 Distillate

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

Nested rollout policy adaptation for Monte Carlo tree search  

Science Conference Proceedings (OSTI)

Monte Carlo tree search (MCTS) methods have had recent success in games, planning, and optimization. MCTS uses results from rollouts to guide search; a rollout is a path that descends the tree with a randomized decision at each ply until reaching a leaf. ...

Christopher D. Rosin

2011-07-01T23:59:59.000Z

202

User Manual - Crystal Ball Monte Carlo POD Simulator  

Science Conference Proceedings (OSTI)

This report provides a user manual for a Monte Carlo simulator using Crystal Ball a spreadsheet add-inthat can be used to predict a noise-dependent structural probability of detection (POD) for steam generator tube integrity assessments. The simulator uses plant noise as one of its inputs and provides a plant-specific POD for condition monitoring and operational assessment.

2006-09-18T23:59:59.000Z

203

Monte Carlo study of self-heating in nanoscale devices  

Science Conference Proceedings (OSTI)

Progress in device miniaturization combined with the increase in integrated circuit packing density, as described by Moore's law, have been accompanied by an exponential increase in on-chip heat generation. In this context, there is an increasing demand ... Keywords: Electron transport, Electrothermal modeling, Monte Carlo, Nanoscale semiconductor devices, Nanowire MISFETs, Self-heating, Si/III-V heterostructure FETs, Thermal transport

Toufik Sadi; Robert W. Kelsall; Neil J. Pilgrim; Jean-Luc Thobel; François Dessenne

2012-03-01T23:59:59.000Z

204

Monte Carlo algorithms for evaluating Sobol' sensitivity indices  

Science Conference Proceedings (OSTI)

Sensitivity analysis is a powerful technique used to determine robustness, reliability and efficiency of a model. The main problem in this procedure is the evaluating total sensitivity indices that measure a parameter's main effect and all the interactions ... Keywords: Adaptive Monte Carlo algorithm, Global sensitivity indices, Multidimensional numerical integration, Sensitivity analysis

I. Dimov; R. Georgieva

2010-11-01T23:59:59.000Z

205

Monte-carlo calculations for some problems of quantum mechanics  

Science Conference Proceedings (OSTI)

The Monte-Carlo technique for the calculations of functional integral in two one-dimensional quantum-mechanical problems had been applied. The energies of the bound states in some potential wells were obtained using this method. Also some peculiarities in the calculation of the kinetic energy in the ground state had been studied.

Novoselov, A. A., E-mail: novoselov@goa.bog.msu.ru; Pavlovsky, O. V.; Ulybyshev, M. V. [Moscow State University (Russian Federation)

2012-09-15T23:59:59.000Z

206

Monte Carlo Simulation of Solar Reflectances for Cloudy Atmospheres  

Science Conference Proceedings (OSTI)

Monte Carlo simulations of solar radiative transfer were performed for a well-resolved, large, three-dimensional (3D) domain of boundary layer cloud simulated by a cloud-resolving model. In order to represent 3D distributions of optical ...

H. W. Barker; R. K. Goldstein; D. E. Stevens

2003-08-01T23:59:59.000Z

207

Monte Carlo simulation of neutral beam injection into fusion reactors  

SciTech Connect

Motivations and techniques for the Monte Carlo computer simulation of energetic neutral beam injection for fusion reactors are described. The versatility of this approach allows a significantly more sophisticated treatment of charge transfer collision phenomena and consequent effects on engineering design than available from prior work. Exemplary results for a mirror Fusion Engineering Research Facility (FERF) are discussed. (auth)

Miller, R.L.

1975-09-15T23:59:59.000Z

208

Forecasting Hotel Arrivals and Occupancy Using Monte Carlo Simulation  

E-Print Network (OSTI)

Forecasting Hotel Arrivals and Occupancy Using Monte Carlo Simulation Athanasius Zakhary Faculty University, Giza, Egypt (n.elgayar@fci-cu.edu.eg) #12;Abstract Forecasting hotel arrivals and occupancy simulation approach for the arrivals and occupancy forecasting problem. In this approach we simulate

Atiya, Amir

209

Monte Carlo: in the beginning and some great expectations  

SciTech Connect

The central theme will be on the historical setting and origins of the Monte Carlo Method. The scene was post-war Los Alamos Scientific Laboratory. There was an inevitability about the Monte Carlo Event: the ENIAC had recently enjoyed its meteoric rise (on a classified Los Alamos problem); Stan Ulam had returned to Los Alamos; John von Neumann was a frequent visitor. Techniques, algorithms, and applications developed rapidly at Los Alamos. Soon, the fascination of the Method reached wider horizons. The first paper was submitted for publication in the spring of 1949. In the summer of 1949, the first open conference was held at the University of California at Los Angeles. Of some interst perhaps is an account of Fermi's earlier, independent application in neutron moderation studies while at the University of Rome. The quantum leap expected with the advent of massively parallel processors will provide stimuli for very ambitious applications of the Monte Carlo Method in disciplines ranging from field theories to cosmology, including more realistic models in the neurosciences. A structure of multi-instruction sets for parallel processing is ideally suited for the Monte Carlo approach. One may even hope for a modest hardening of the soft sciences.

Metropolis, N.

1985-01-01T23:59:59.000Z

210

A Monte Carlo electron transport code for the desktop computer  

Science Conference Proceedings (OSTI)

A Monte Carlo electron transport code for the desktop computer is applied to the problem of determining the radiation dose throughout an oblique?surface heterogeneous medium. Absorbed?dose distributions are obtained for 10 MeV electrons incident upon flat?surface and oblique?surface water phantoms

1992-01-01T23:59:59.000Z

211

Addendum to “Event-chain Monte Carlo algorithms for hard-sphere systems”  

E-Print Network (OSTI)

We extend the event-chain Monte Carlo algorithm from hard-sphere interactions to general potentials. This event-driven Monte Carlo algorithm is nonlocal and rejection free and allows for the breaking of detailed balance. ...

Bernard, Etienne

212

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

213

The continuous configurational Boltzmann biased direct Monte Carlo method for free energy properties of polymer chains  

Science Conference Proceedings (OSTI)

We develop here a highly efficient variant of the Monte Carlo method for direct evaluation of the partition function

Jiro Sadanobu; William A. Goddard III

1997-01-01T23:59:59.000Z

214

Characterization of plasma and laser conditions for single hot spot interaction experiments  

Science Conference Proceedings (OSTI)

The LANL TRIDENT laser system is being used for fundamental experiments which study the interaction of self-focusing, stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in a single (diffraction limited) laser hot spot in order to better understand the coupling between these plasma instabilities. The diffraction limited beam mimics a single hot spot found in speckle distributions that are typical of random or kinoform phase plate (RPP or KPP) smoothing. A long scale length, hot plasma ({approximately} 1 mm, {approximately} 0.5 keV) is created by a separate heater beam, and the single hot spot beam is used to drive parametric instabilities. The focal plane distribution and wavefront of the single hot spot beam are characterized, and the intensity of the single hot spot can be varied between 10{sup 14}--10{sup 16} W/cm{sup 2}. The plasma density, temperature, and flow profiles are measured using gated imaging spectroscopy of collective Thomson scattering. Results of the laser and plasma characterization, and initial results of backscattered SRS, SBS, and beam steering in a flowing plasma are presented.

Montgomery, D.S.; Johnson, R.P.; Cobble, J.A.; Fernandez, J.C.; Lindman, E.L.; Rose, H.A. [Los Alamos National Lab., NM (United States); Estabrook, K.G. [Lawrence Livermore National Lab., CA (United States)

1998-11-01T23:59:59.000Z

215

Analysis of communication costs for domain decomposed Monte Carlo methods in nuclear reactor analysis  

Science Conference Proceedings (OSTI)

A domain decomposed Monte Carlo communication kernel is used to carry out performance tests to establish the feasibility of using Monte Carlo techniques for practical Light Water Reactor (LWR) core analyses. The results of the prototype code are interpreted ... Keywords: Monte Carlo, Neutron transport, Performance modeling, Reactor analysis

A. Siegel; K. Smith; P. Fischer; V. Mahadevan

2012-04-01T23:59:59.000Z

216

Data decomposition of Monte Carlo particle transport simulations via tally servers  

Science Conference Proceedings (OSTI)

An algorithm for decomposing large tally data in Monte Carlo particle transport simulations is developed, analyzed, and implemented in a continuous-energy Monte Carlo code, OpenMC. The algorithm is based on a non-overlapping decomposition of compute ... Keywords: Data decomposition, Exascale, Monte Carlo, Neutron transport, Tally server

Paul K. Romano, Andrew R. Siegel, Benoit Forget, Kord Smith

2013-11-01T23:59:59.000Z

217

Shadow hybrid Monte Carlo: an efficient propagator in phase space of macromolecules  

Science Conference Proceedings (OSTI)

Shadow hybrid Monte Carlo (SHMC) is a new method for sampling the phase space of large molecules, particularly biological molecules. It improves sampling of hybrid Monte Carlo (HMC) by allowing larger time steps and system sizes in the molecular dynamics ... Keywords: conformational sampling, hybrid Monte Carlo, modified Hamiltonian, sampling methods, symplectic integrator

Jesús A. Izaguirre; Scott S. Hampton

2004-11-01T23:59:59.000Z

218

A sequential Monte Carlo/Quantum Mechanics study of the dipole polarizability of liquid benzene  

Science Conference Proceedings (OSTI)

Metropolis Monte Carlo classical simulation and quantum mechanical calculations are performed to obtain the dipole polarizability of liquid benzene. Super-molecular configurations are sampled from NVT Monte Carlo simulation of liquid benzene at room ... Keywords: Monte Carlo simulation, density-functional theory, intermediate-neglect of differential overlap (INDO), liquid benzene, polarizability

Eudes E. Fileti; Sylvio Canuto

2004-12-01T23:59:59.000Z

219

New EM Technology: Spray Lights up Contamination Hot Spots | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

New EM Technology: Spray Lights up Contamination Hot Spots New EM Technology: Spray Lights up Contamination Hot Spots New EM Technology: Spray Lights up Contamination Hot Spots July 24, 2013 - 12:00pm Addthis The ORNL researchers conducted a test in which they sprayed the scintillating phosphor on simulated debris material marked with technetium-99. The ORNL researchers conducted a test in which they sprayed the scintillating phosphor on simulated debris material marked with technetium-99. An image intensified camera system captured an image of the simulated debris material in dark conditions. An image intensified camera system captured an image of the simulated debris material in dark conditions. The ORNL researchers conducted a test in which they sprayed the scintillating phosphor on simulated debris material marked with technetium-99.

220

Roosting Spot for These Nocturnal Mammals is Just Batty | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Roosting Spot for These Nocturnal Mammals is Just Batty Roosting Spot for These Nocturnal Mammals is Just Batty Roosting Spot for These Nocturnal Mammals is Just Batty November 7, 2012 - 3:05pm Addthis A Yuma bat flying inside the clearwell at 100-F Area. | Photo courtesy of the Office of Environmental Management. A Yuma bat flying inside the clearwell at 100-F Area. | Photo courtesy of the Office of Environmental Management. David Sheeley Editor/Writer for Environmental Management's Office of External Affairs What are the key facts? Yuma bats reside in a clearwell, a concrete structure formerly used to filter water from the Columbia River for cooling a reactor. Yuma bats have buff-colored bodies that are about 1.5 to 2 inches long with a wingspan of up to 9 inches. Think about the places where bats roost, and abandoned cab-ins, attics,

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

Uniform irradiation of adjustable target spots in high-power laser driver  

Science Conference Proceedings (OSTI)

For smoothing and shaping the on-target laser patterns flexibly in high-power laser drivers, a scheme has been developed that includes a zoom lens array and two-dimensional smoothing by spectral dispersion (SSD). The size of the target pattern can be controlled handily by adjusting the focal length of the zoom lens array, while the profile of the pattern can be shaped by fine tuning the distance between the target and the focal plane of the principal focusing lens. High-frequency stripes inside the pattern caused by beamlet interference are wiped off by spectral dispersion. Detailed simulations indicate that SSD works somewhat differently for spots of different sizes. For small spots, SSD mainly smooths the intensity modulation of low-to-middle spatial frequency, while for large spots, SSD sweeps the fine speckle structure to reduce nonuniformity of middle-to-high frequency. Spatial spectra of the target patterns are given and their uniformity is evaluated.

Jiang Xiujuan; Li Jinghui; Li Huagang; Li Yang; Lin Zunqi

2011-09-20T23:59:59.000Z

222

New EM Technology: Spray Lights up Contamination Hot Spots | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

EM Technology: Spray Lights up Contamination Hot Spots EM Technology: Spray Lights up Contamination Hot Spots New EM Technology: Spray Lights up Contamination Hot Spots July 24, 2013 - 12:00pm Addthis The ORNL researchers conducted a test in which they sprayed the scintillating phosphor on simulated debris material marked with technetium-99. The ORNL researchers conducted a test in which they sprayed the scintillating phosphor on simulated debris material marked with technetium-99. An image intensified camera system captured an image of the simulated debris material in dark conditions. An image intensified camera system captured an image of the simulated debris material in dark conditions. The ORNL researchers conducted a test in which they sprayed the scintillating phosphor on simulated debris material marked with technetium-99.

223

,"Weekly Henry Hub Natural Gas Spot Price (Dollars per Million Btu)"  

U.S. Energy Information Administration (EIA) Indexed Site

Henry Hub Natural Gas Spot Price (Dollars per Million Btu)" Henry Hub Natural Gas Spot Price (Dollars per Million Btu)" ,"Click worksheet name or tab at bottom for data" ,"Worksheet Name","Description","# Of Series","Frequency","Latest Data for" ,"Data 1","Weekly Henry Hub Natural Gas Spot Price (Dollars per Million Btu)",1,"Weekly","12/13/2013" ,"Release Date:","12/18/2013" ,"Next Release Date:","12/27/2013" ,"Excel File Name:","rngwhhdw.xls" ,"Available from Web Page:","http://tonto.eia.gov/dnav/ng/hist/rngwhhdw.htm" ,"Source:" ,"For Help, Contact:","infoctr@eia.doe.gov" ,,"(202) 586-8800",,,"12/18/2013 12:22:22 PM"

224

Development of the Dried Spot Sample Preparation Methodology and Applications to XRMF Analysis  

Science Conference Proceedings (OSTI)

The dried spot method has significant potential for trace elemental analysis using x-ray fluorescence. Small sample size coupled with spatially resolved excitation offers increased sensitivity for aqueous solutions. The primary limitation in applying this method to routine analyses is that much of the method development and fundamental aspects have not been investigated. We have studied the effects of a number of parameters on the quantitative capabilities of the dried spot method. These include thin-film substrates, drying methods, and solution composition. The small sample size offers opportunities for the analysis of a wide array of sample types including highly radioactive specimens.

Colletti, Lisa P.; Havrilla, George J.

1997-12-31T23:59:59.000Z

225

Load Balancing Of Parallel Monte Carlo Transport Calculations  

National Nuclear Security Administration (NNSA)

Load Balancing Of Parallel Load Balancing Of Parallel Monte Carlo Transport Calculations R.J. Procassini, M. J. O'Brien and J.M. Taylor Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94551 The performance of parallel Monte Carlo transport calculations which use both spatial and particle parallelism is increased by dynamically assigning processors to the most worked domains. Since the particle work load varies over the course of the simulation, each cycle this algorithm determines if dynamic load balancing would speed up the calculation. If load balancing is required, a small number of particle communications are initiated in order to achieve load balance. This method has decreased the parallel run time by more than a factor of three for certain criticality

226

Ab initio Monte Carlo investigation of small lithium clusters.  

Science Conference Proceedings (OSTI)

Structural and thermal properties of small lithium clusters are studied using ab initio-based Monte Carlo simulations. The ab initio scheme uses a Hartree-Fock/density functional treatment of the electronic structure combined with a jump-walking Monte Carlo sampling of nuclear configurations. Structural forms of Li{sub 8} and Li{sub 9}{sup +} clusters are obtained and their thermal properties analyzed in terms of probability distributions of the cluster potential energy, average potential energy and configurational heat capacity all considered as a function of the cluster temperature. Details of the gradual evolution with temperature of the structural forms sampled are examined. Temperatures characterizing the onset of structural changes and isomer coexistence are identified for both clusters.

Srinivas, S.

1999-06-16T23:59:59.000Z

227

Quantum Monte Carlo with Coupled-Cluster wave functions  

E-Print Network (OSTI)

We introduce a novel many body method which combines two powerful many body techniques, viz., quantum Monte Carlo and coupled cluster theory. Coupled cluster wave functions are introduced as importance functions in a Monte Carlo method designed for the configuration interaction framework to provide rigorous upper bounds to the ground state energy. We benchmark our method on the homogeneous electron gas in momentum space. The importance function used is the coupled cluster doubles wave function. We show that the computational resources required in our method scale polynomially with system size. Our energy upper bounds are in very good agreement with previous calculations of similar accuracy, and they can be systematically improved by including higher order excitations in the coupled cluster wave function.

Roggero, Alessandro; Pederiva, Francesco

2013-01-01T23:59:59.000Z

228

The dynamics of quantum criticality: Quantum Monte Carlo and holography  

E-Print Network (OSTI)

Understanding the real time dynamics of systems near quantum critical points at non-zero temperatures constitutes an important yet challenging problem, especially in two spatial dimensions where interactions are strong. We present detailed quantum Monte Carlo results for two separate realizations of the superfluid-insulator transition of bosons on a lattice: their low-frequency conductivities are found to have the same universal dependence on imaginary frequency and temperature. We then use the structure of the real time dynamics of conformal field theories described by the holographic gauge/gravity duality to make progress on the difficult problem of analytically continuing the Monte Carlo data to real time. Our method yields quantitative and experimentally testable results on the frequency-dependent conductivity at the quantum critical point, and on the spectrum of quasinormal modes in the vicinity of the superfluid-insulator quantum phase transition. Extensions to other observables and universality classes are discussed.

William Witczak-Krempa; Erik Sorensen; Subir Sachdev

2013-09-11T23:59:59.000Z

229

Quantum Monte Carlo with Coupled-Cluster wave functions  

E-Print Network (OSTI)

We introduce a novel many body method which combines two powerful many body techniques, viz., quantum Monte Carlo and coupled cluster theory. Coupled cluster wave functions are introduced as importance functions in a Monte Carlo method designed for the configuration interaction framework to provide rigorous upper bounds to the ground state energy. We benchmark our method on the homogeneous electron gas in momentum space. The importance function used is the coupled cluster doubles wave function. We show that the computational resources required in our method scale polynomially with system size. Our energy upper bounds are in very good agreement with previous calculations of similar accuracy, and they can be systematically improved by including higher order excitations in the coupled cluster wave function.

Alessandro Roggero; Abhishek Mukherjee; Francesco Pederiva

2013-04-04T23:59:59.000Z

230

Monte Carlo Simulations of Neutron Oil well Logging Tools  

E-Print Network (OSTI)

Monte Carlo simulations of simple neutron oil well logging tools into typical geological formations are presented.The simulated tools consist of both 14 MeV pulsed and continuous Am-Be neutron sources with time gated and continuous gamma ray detectors respectively.The geological formation consists of pure limestone with 15% absolute porosity in a wide range of oil saturation.The particle transport was performed with the Monte Carlo N-Particle Transport Code System, MCNP-4B.Several gamma ray spectra were obtained at the detector position that allow to perform composition analysis of the formation.In particular, the ratio C/O was analyzed as an indicator of oil saturation.Further calculations are proposed to simulate actual detector responses in order to contribute to understand the relation between the detector response with the formation composition

Azcurra, M

2002-01-01T23:59:59.000Z

231

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

Science Conference Proceedings (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

232

Towards a Revised Monte Carlo Neutral Particle Surface Interaction Model  

DOE Green Energy (OSTI)

The components of the neutral- and plasma-surface interaction model used in the Monte Carlo neutral transport code DEGAS 2 are reviewed. The idealized surfaces and processes handled by that model are inadequate for accurately simulating neutral transport behavior in present day and future fusion devices. We identify some of the physical processes missing from the model, such as mixed materials and implanted hydrogen, and make some suggestions for improving the model.

D.P. Stotler

2005-06-09T23:59:59.000Z

233

Multi-Determinant Wave-functions in Quantum Monte Carlo  

Science Conference Proceedings (OSTI)

Quantum Monte Carlo methods have received considerable attention over the last decades due to the great promise they have for the direct solution to the many-body Schrodinger equation for electronic systems. Thanks to a low scaling with number of particles, they present one of the best alternatives in the accurate study of large systems and solid state calculations. In spite of such promise, the method has not become popular in the quantum chemistry community, mainly due to the lack of control over the fixed-node error which can be large in many cases. In this article we present the application of large multi-determinant expansions in quantum Monte Carlo, studying its performance with first row dimers and the 55 molecules of the G1 test set. We demonstrate the potential of the wave-function to systematically reduce the fixed-node error in the calculations, achieving chemical accuracy in almost all cases studied. When compared to traditional methods in quantum chemistry, the results show a marked improvement over most methods including MP2, CCSD(T) and DFT with various functionals; in fact the only method able to produce better results is the explicitly-correlated CCSD(T) method with a large basis set. With recent developments in trial wave functions and algorithmic improvements in Quantum Monte Carlo, we are quickly approaching a time where the method can become the standard in the study of large molecular systems and solids.

Morales, Miguel A [Lawrence Livermore National Laboratory (LLNL); Mcminis, Jeremy [University of Illinois, Urbana-Champaign; Clark, Bryan K. [Princeton University; Kim, Jeongnim [ORNL; Scuseria, Gustavo E [Rice University

2012-01-01T23:59:59.000Z

234

Coupled MHD-Monte Carlo transport model for dense plasmas  

SciTech Connect

A two-dimensional, two fluid model of the MHD equations has been coupled to a Monte Carlo transport model of high energy, non-Maxwellian ions. The MHD part of the model assumes complete ionization and includes a perfect gas law for a scalar pressure, a tensor artificial viscosity, electron and ion thermal conduction, electron-ion coupling, and a radiation loss term. A simple Ohm's Law is used with a B/sub theta/ magnetic field. The MHD equations were solved in Lagrangian coordinates. The conservation equations were differenced explicitly and the diffusion-type equations implicitly using the splitting technique. The Monte Carlo model solves the equation of motion for high energy ions, moving through and suffering small and large angle collisions with the fluid Maxwellian plasma. The source of high energy ions is the thermonuclear reactions of the hydrogen isotopes, or it may be an externally injected beam of neutralized ions. In addition to using the usual Maxwell averaged thermonuclear cross sections for calculating the number of reactions taking place within the Maxwellian plasma, the high energy ions may suffer collisions resulting in a reaction. In the Monte Carlo model all neutrons are assumed to escape, and all energetic ions of Z less than or equal to 2 are followed. (auth)

Chandler, W.P.

1975-06-01T23:59:59.000Z

235

Resistance spot welding of Ti-6A1-4V alloy  

SciTech Connect

The effects of weld power, electrode force, electrode tip radius, and elapsed time between cleaning and welding on resistance spot welds in Ti-6Al-4V alloy were evaluated. The alloy is weldable by this technique, and a wide latitude can be taken in processing variables.

Jarboe, D.M.

1980-06-01T23:59:59.000Z

236

On the Complexity of Market Power Assessment in the Electricity Spot Markets  

E-Print Network (OSTI)

On the Complexity of Market Power Assessment in the Electricity Spot Markets Poonsaeng Visudhiphan David Bertagnoli of the New England ISO for the informative discussion and insights. This work was supported in part by the members of the Massachusetts Institute of Technology Energy Laboratory's Consortium

Ilic, Marija D.

237

Implementing automatic spot addressing and contour based segmentation in microarray image analysis  

Science Conference Proceedings (OSTI)

DNA microarrays have become a widely used technique by geneticists to diagnose or treat diseases through gene expression. The process of analysis gene expression with DNA microarrays is based on the hybridization of a tissue's DNA sequence into a substrate ... Keywords: DNA microarrays, contour segmentation, edge detection, image processing, segmentation, spot addressing

Alexandra Oliveros; Miguel Sotaquirá

2008-08-01T23:59:59.000Z

238

Microscopic Analysis of Agriculture Products, 4th EditionChapter 9 Microchemical Spot Tests  

Science Conference Proceedings (OSTI)

Microscopic Analysis of Agriculture Products, 4th Edition Chapter 9 Microchemical Spot Tests Methods and Analyses eChapters Methods - Analyses Books AOCS 6C2FB81BF33EA47CEF1B98AD0BE2A9CB Press Downloadable pdf...

239

Hard prey, soft jaws and the ontogeny of feeding mechanics in the spotted ratfish  

E-Print Network (OSTI)

Hard prey, soft jaws and the ontogeny of feeding mechanics in the spotted ratfish Hydrolagus colliei is a holocephalan fish that consumes hard prey (durophagy) but lacks many morphological characters (Chondrichthyes: Holocephali) have branded them as hard prey specialists (Didier 1995; Grogan & Lund 2004

Summers, Adam P.

240

ESTIA: A Real-Time Consumer Control Scheme for Space Conditioning Usage under Spot Electricity Pricing  

E-Print Network (OSTI)

rendering price forecasting practically unnecessary and reducing the data and computing requirements Pricing P. Constantopoulos University of Crete and Research Centre of Crete Heraklion, Crete, Greece F are now relatively inexpensive, so that hourly (or more frequent) "spot prices" of electri- city could

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

ESTIA: A RealTime Consumer Control Scheme for Space Conditioning Usage under Spot Electricity Pricing  

E-Print Network (OSTI)

, thereby rendering price forecasting practically unnecessary and reducing the data and computing Pricing P. Constantopoulos University of Crete and Research Centre of Crete Heraklion, Crete, Greece F are now relatively inexpensive, so that hourly (or more frequent) "spot prices" of electri­ city could

242

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

Science Conference Proceedings (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

243

Kinetic Lattice Monte Carlo Simulation ofKinetic Lattice Monte Carlo Simulation of Polycrystalline Thin film growthPolycrystalline Thin film growth  

E-Print Network (OSTI)

grain orientations s The first application of this code is to the growth of Mo tips, including chemicalKinetic Lattice Monte Carlo Simulation ofKinetic Lattice Monte Carlo Simulation of Polycrystalline Applications Motorola National Science Foundation National Center for Supercomputer Applications Motorola #12

Adams, James B

244

Continuous-Estimator Representation for Monte Carlo Criticality Diagnostics  

Science Conference Proceedings (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

245

Bounded limit for the Monte Carlo point-flux-estimator  

Science Conference Proceedings (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

246

Process Characterisation with Monte-Carlo Wave-Functions  

E-Print Network (OSTI)

We present a numerically efficient method for the characterisation of a quantum process subject to dissipation and noise. The master equation evolution of a maximally entangled state of the quantum system and a non-evolving ancilla system is simulated by Monte-Carlo wave-functions. We show how each stochastic state vectors provides quantities that are readily combined into an average process \\chi-matrix. Our method significantly reduces the computational complexity in comparison with standard characterisation methods. It also readily provides an upper bound on the trace distance between the ideal and simulated process based on the evolution of only a single wave function of the entangled system.

Jake Gulliksen; D. D. Bhaktavatsala Rao; Klaus Mølmer

2013-09-19T23:59:59.000Z

247

Adaptively Learning an Importance Function Using Transport Constrained Monte Carlo  

Science Conference Proceedings (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

248

Validation of Phonon Physics in the CDMS Detector Monte Carlo  

SciTech Connect

The SuperCDMS collaboration is a dark matter search effort aimed at detecting the scattering of WIMP dark matter from nuclei in cryogenic germanium targets. The CDMS Detector Monte Carlo (CDMS-DMC) is a simulation tool aimed at achieving a deeper understanding of the performance of the SuperCDMS detectors and aiding the dark matter search analysis. We present results from validation of the phonon physics described in the CDMS-DMC and outline work towards utilizing it in future WIMP search analyses.

McCarthy, K.A.; Leman, S.W.; Anderson, A.J.; /MIT; Brandt, D.; /SLAC; Brink, P.L.; Cabrera, B.; Cherry, M.; /Stanford U.; Do Couto E Silva, E.; /SLAC; Cushman, P.; /Minnesota U.; Doughty, T.; /UC, Berkeley; Figueroa-Feliciano, E.; /MIT; Kim, P.; /SLAC; Mirabolfathi, N.; /UC, Berkeley; Novak, L.; /Stanford U.; Partridge, R.; /SLAC; Pyle, M.; /Stanford U.; Reisetter, A.; /Minnesota U. /St. Olaf Coll.; Resch, R.; /SLAC; Sadoulet, B.; Serfass, B.; Sundqvist, K.M.; /UC, Berkeley /Stanford U.

2012-06-06T23:59:59.000Z

249

An alternative Monte Carlo approach to the thermal radiative transfer problem  

SciTech Connect

The usual Monte Carlo approach to the thermal radiative transfer problem is to view Monte Carlo as a solution technique for the nonlinear thermal radiative transfer equations. The equations contain time derivatives which are approximated by introducing small time steps. An alternative approach avoids time steps by using Monte Carlo to directly sample the time at which the next event occurs. That is, the time is advanced on a natural event-by-event basis rather than by introducing an artificial time step.

Booth, Thomas E., E-mail: teb@lanl.go [Mail Stop A143, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2011-02-20T23:59:59.000Z

250

Avaliação sócio-econômica e ambiental do complexo hidrelétrico de Belo Monte.  

E-Print Network (OSTI)

??O presente trabalho tem como objetivo tratar da construção do Complexo Hidrelétrico de Belo Monte, trazendo informações sobre aspectos econômicos, de produção e consumo energético.… (more)

Neidja Cristine Silvestre Leitão

2005-01-01T23:59:59.000Z

251

MINT: a Computer Program for Adaptive Monte Carlo Integration and Generation of Unweighted Distributions  

E-Print Network (OSTI)

In this note I illustrate the program MINT, a FORTRAN program for Monte Carlo adaptive integration and generation of unweighted distributions.

Nason, P

2007-01-01T23:59:59.000Z

252

MINT: a Computer Program for Adaptive Monte Carlo Integration and Generation of Unweighted Distributions  

E-Print Network (OSTI)

In this note I illustrate the program MINT, a FORTRAN program for Monte Carlo adaptive integration and generation of unweighted distributions.

P. Nason

2007-09-13T23:59:59.000Z

253

Observations of the formation and maintenance of beach cusps on Del Monte Beach in Monterey, California .  

E-Print Network (OSTI)

??During the period of 5 April 2001 - 16 May 2001, topographic surveys of Del Monte beach in Monterey, California, were performed on a regular… (more)

Miller, Gregory Chad.

2001-01-01T23:59:59.000Z

254

,"Henry Hub Natural Gas Spot Price (Dollars per Million Btu)"  

U.S. Energy Information Administration (EIA) Indexed Site

Annual",2012 Annual",2012 ,"Release Date:","12/18/2013" ,"Next Release Date:","12/27/2013" ,"Excel File Name:","rngwhhda.xls" ,"Available from Web Page:","http://tonto.eia.gov/dnav/ng/hist/rngwhhda.htm" ,"Source:" ,"For Help, Contact:","infoctr@eia.doe.gov" ,,"(202) 586-8800",,,"12/18/2013 12:22:19 PM" "Back to Contents","Data 1: Henry Hub Natural Gas Spot Price (Dollars per Million Btu)" "Sourcekey","RNGWHHD" "Date","Henry Hub Natural Gas Spot Price (Dollars per Million Btu)" 35611,2.49 35976,2.09 36341,2.27 36707,4.31 37072,3.96 37437,3.38 37802,5.47 38168,5.89 38533,8.69 38898,6.73

255

Magnetism, chemical spots, and stratification in the HgMn star phi Phoenicis  

E-Print Network (OSTI)

Mercury-manganese (HgMn) stars have been considered as non-magnetic and non-variable chemically peculiar (CP) stars for a long time. However, recent discoveries of the variability in spectral line profiles suggested an inhomogeneous surface distribution of chemical elements in some HgMn stars. From the studies of other CP stars it is known that magnetic field plays a key role in the formation of surface spots. All attempts to find magnetic fields in HgMn stars yielded negative results. In this study, we investigate a possible presence of the magnetic field in phi Phe (HD 11753) and reconstruct surface distribution of chemical elements that show variability in spectral lines. We also test a hypothesis that magnetic field is concentrated in chemical spots and look into the possibility that some chemical elements are stratified with depth in the stellar atmosphere.

Makaganiuk, V; Piskunov, N; Jeffers, S V; Johns-Krull, C M; Keller, C U; Rodenhuis, M; Snik, F; Stempels, H C; Valenti, J A

2011-01-01T23:59:59.000Z

256

CoolSpots: Reducing the Power Consumption of Wireless Mobile Devices with Multiple Radio Interfaces  

E-Print Network (OSTI)

CoolSpots enable a wireless mobile device to automatically switch between multiple radio interfaces, such as WiFi and Bluetooth, in order to increase battery lifetime. The main contribution of this work is an exploration of the policies that enable a system to switch among these interfaces, each with diverse radio characteristics and different ranges, in order to save power – supported by detailed quantitative measurements. The system and policies do not require any changes to the mobile applications themselves, and changes required to existing infrastructure are minimal. Results are reported for a suite of commonly used applications, such as file transfer, web browsing, and streaming media, across a range of operating conditions. Experimental validation of the CoolSpot system on a mobile research platform shows substantial energy savings: more than a 50 % reduction in energy consumption of the wireless subsystem is possible, with an associated increase in the effective battery lifetime.

Trevor Pering; Yuvraj Agarwal; Rajesh Gupta; Comm Power

2006-01-01T23:59:59.000Z

257

Spot pricing of electricity and ancillary services in a competitive California market  

Science Conference Proceedings (OSTI)

Typically, in competitive electricity markets, the vertically integrated utilities that were responsible for ensuring system reliability in their own service territories, or groups of territories, cease to exist. The burden falls to an independent system operator (ISO) to ensure that enough ancillary services (AS) are available for safe, stable, and reliable operation of the grid, typically defined, in part, as compliance with officially approved engineering specifications for minimum levels of AS. In order to characterize the behavior of market participants (generators, retailers, and an ISO) in a competitive electricity market with reliability requirements, spot markets for both electricity and AS are modeled. By assuming that each participant seeks to maximize its wealth and that all markets clear, we solve for the optimal quantities of electricity and AS traded in the spot market by all participants, as well as the market clearing prices for each.

Siddiqui, A.S.; Marnay, C.; Khavkin, M.

2000-11-01T23:59:59.000Z

258

Point and Interval Forecasting of Spot Electricity Prices: Linear vs. Non-Linear Time Series Models  

E-Print Network (OSTI)

In this paper we assess the short-term forecasting power of different time series models in the electricity spot market. In particular we calibrate AR/ARX (”X” stands for exogenous/fundamental variable — system load in our study), AR/ARX-GARCH, TAR/TARX and Markov regime-switching models to California Power Exchange (CalPX) system spot prices. We then use them for out-ofsample point and interval forecasting in normal and extremely volatile periods preceding the market crash in winter 2000/2001. We find evidence that (i) non-linear, threshold regime-switching (TAR/TARX) models outperform their linear counterparts, both in point and interval forecasting, and that (ii) an additional GARCH component generally decreases point forecasting efficiency. Interestingly, the former result challenges a number of previously published studies on the failure of non-linear regime-switching models in forecasting.

Adam Misiorek; Stefan Trueck; Rafal Weron

2006-01-01T23:59:59.000Z

259

,"Henry Hub Natural Gas Spot Price (Dollars per Million Btu)"  

U.S. Energy Information Administration (EIA) Indexed Site

Daily","12/16/2013" Daily","12/16/2013" ,"Release Date:","12/18/2013" ,"Next Release Date:","12/27/2013" ,"Excel File Name:","rngwhhdd.xls" ,"Available from Web Page:","http://tonto.eia.gov/dnav/ng/hist/rngwhhdd.htm" ,"Source:" ,"For Help, Contact:","infoctr@eia.doe.gov" ,,"(202) 586-8800",,,"12/18/2013 12:22:24 PM" "Back to Contents","Data 1: Henry Hub Natural Gas Spot Price (Dollars per Million Btu)" "Sourcekey","RNGWHHD" "Date","Henry Hub Natural Gas Spot Price (Dollars per Million Btu)" 35437,3.82 35438,3.8 35439,3.61 35440,3.92 35443,4 35444,4.01 35445,4.34 35446,4.71 35447,3.91

260

Two self-referencing methods for the measurement of beam spot position  

Science Conference Proceedings (OSTI)

Purpose: Two quantitative methods of measuring electron beam spot position with respect to the collimator axis of rotation (CAOR) are described. Methods: Method 1 uses a cylindrical ion chamber (IC) mounted on a jig corotational with the collimator making the relationship among the chamber, jaws, and CAOR fixed and independent of collimator angle. A jaw parallel to the IC axis is set to zero and the IC position adjusted so that the IC signal is approximately 50% of the open field value, providing a large dose gradient in the region of the IC. The cGy/MU value is measured as a function of collimator rotation, e.g., every 30 Degree-Sign . If the beam spot does not lie on the CAOR, the signal from the ion chamber will vary with collimator rotation. Based on a measured spatial sensitivity, the distance of the beam spot from the CAOR can be calculated from the IC signal variation with rotation. The 2nd method is image based. Two stainless steel rods, 3 mm in diameter, are mounted to a jig attached to the Linac collimator. The rods, offset from the CAOR, lay in different planes normal to the CAOR, one at 158 cm SSD and the other at 70 cm SSD. As the collimator rotates the rods move tangent along an envelope circle, the centers of which are on the CAOR in their respective planes. Three images, each at a different collimator rotation, containing the shadows of both rods, are acquired on the Linac EPID. At each angle the shadow of the rods on the EPID defines lines tangent to the projection of the envelope circles. From these the authors determine the projected centers of the two circles at different heights. From the distance of these two points using the two heights and the source to EPID distance, the authors calculate the distance of the beam spot from the CAOR. Measurements with all two techniques were performed on an Elekta Linac. Measurements were performed with the beam spot in nominal clinical position and in a deliberately offset position. Measurements were also performed using the Flexmap image registration/ball-bearing test. Results: Within their uncertainties, both methods report the same beam spot displacement. In clinical use, a total of 203 monthly beam spot measurements on 14 different beams showed an average displacement of 0.11 mm ({sigma}= 0.07 mm) in-plane and 0.10 mm ({sigma}= 0.07 mm) cross-plane with maximum displacement of 0.37 mm in-plane and 0.34 mm cross-plane. Conclusions: The methods described provide a quantitative measure of beam spot position, are easy to use, and provide another tool for Linac setup and quality assurance. Fundamental to the techniques is that they are self-referencing-i.e., they do not require the user to independently define the CAOR.

Nyiri, Balazs J.; Smale, Jason R.; Gerig, Lee H. [Ottawa Hospital Cancer Centre, Ottawa K1H 8L6 (Canada) and Faculty of Medicine, University of Ottawa, Ottawa K1H 8M5 (Canada); Elekta Canada, Ottawa, Ontario K1Y 1Z3 (Canada); Ottawa Hospital Cancer Centre, Ottawa K1H 8L6 (Canada); Department of Physics, Carleton University, Ottawa K1S 5B6 (Canada) and Faculty of Medicine, University of Ottawa, Ottawa K1H 8M5 (Canada)

2012-12-15T23:59:59.000Z

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.


261

Inference of the optimal pretarget electron beam parameters in a Monte Carlo virtual linac model through simulated annealing  

Science Conference Proceedings (OSTI)

The purpose of this study was to develop an efficient method to determine the optimal intensity distribution of the pretarget electron beam in a Monte Carlo (MC) accelerator model able to most accurately reproduce a set of measured photon field profiles for a given accelerator geometry and nominal photon beam energy. The method has the ability to reduce the number of simulations required to commission a MC accelerator model and has achieved better agreement with measurement than other methods described in literature. The method begins from a cylindrically symmetric pretarget electron beam (radius of 0.5 cm) of uniform intensity. This beam is subdivided into annular regions of fluence for which each region is individually transported through the accelerator head and into a water phantom. A simulated annealing search is then performed to determine the optimal combination of weights of the annular fluences that provide a best match between the measured dose distributions and the weighted sum of annular dose distributions for particular pretarget electron energy. When restricted to Gaussian intensity distributions, the optimization determined an optimal FWHM=1.34 mm for 18.0 MeV electrons, with a RMSE=0.49% on 40x40 cm{sup 2} lateral profiles. When allowed to deviate from Gaussian intensities a further reduction in RMSE was achieved. For our Clinac 21 EX accelerator MC model (based on the 1996 Varian Oncology Systems, Monte Carlo Project package), the optimal unrestricted intensity distribution was found to be a Gaussian-like solution (18.0 MeV, FWHM=1.10 mm, 40x40 cm{sup 2} profile, and RMSE=0.15%) with the presence of an extra focal halo contribution on the order of 10% of the maximum Gaussian intensity. Using the optimally derived intensity, 10x10 and 4x4 cm{sup 2} profiles were found to be in agreement with measurement with a maximum RMSE=0.49%. The optimized Gaussian and unrestricted values of the electron beam FWHM were both within the range of those inferred by focal spot image measurements performed by Jaffray et al.[''X-ray sources of medical linear accelerators: Focal and extra-focal radiation,'' Med. Phys. 20, 1417-1427 (1993)]. The inference of an extra focal pretarget electron component may be an indicator of a deficiency in the MC model and needs further investigation.

Bush, Karl; Zavgorodni, Sergei; Beckham, Wayne [Department of Physics and Astronomy, University of Victoria, P. O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6 (Canada); Department of Medical Physics, British Columbia Cancer Agency-Vancouver Island Center, Victoria, British Columbia V8R 6V5 (Canada) and Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8R 6V5 (Canada)

2009-06-15T23:59:59.000Z

262

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

263

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

SciTech Connect

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

264

Modelling and evaluation of the 3G mobile networks with hot-spot WLANs  

Science Conference Proceedings (OSTI)

An analytical modelling and evaluation approach is developed for the integrated 3G/WLAN networks. The cell residence times of different types of users are modelled as a general distribution to adapt various mobility environments. The explicit expressions ... Keywords: 3G cellular networks, CAC, call admission control, channel occupancy time, horizontal handoff, hot spot WLANs, integration, local area networks, mobile networks, modelling, performance evaluation, traffic analysis, vertical handoff, wireless LANs, wireless networks

Shensheng Tang; Wei Li

2007-01-01T23:59:59.000Z

265

Monte Carlo parameter studies and uncertainty analyses with MCNP5  

SciTech Connect

A software tool called mcnp-pstudy has been developed to automate the setup, execution, and collection of results from a series of MCNPS Monte Carlo calculations. This tool provides a convenient means of performing parameter studies, total uncertainty analyses, parallel job execution on clusters, stochastic geometry modeling, and other types of calculations where a series of MCNPS jobs must be performed with varying problem input specifications. Monte Carlo codes are being used for a wide variety of applications today due to their accurate physical modeling and the speed of today's computers. In most applications for design work, experiment analysis, and benchmark calculations, it is common to run many calculations, not just one, to examine the effects of design tolerances, experimental uncertainties, or variations in modeling features. We have developed a software tool for use with MCNP5 to automate this process. The tool, mcnp-pstudy, is used to automate the operations of preparing a series of MCNP5 input files, running the calculations, and collecting the results. Using this tool, parameter studies, total uncertainty analyses, or repeated (possibly parallel) calculations with MCNP5 can be performed easily. Essentially no extra user setup time is required beyond that of preparing a single MCNP5 input file.

Brown, F. B. (Forrest B.); Sweezy, J. E. (Jeremy E.); Hayes, R. B. (Robert B.)

2004-01-01T23:59:59.000Z

266

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

Science Conference Proceedings (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

267

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

268

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

E-Print Network (OSTI)

Given the role electricity and natural gas sectors play in the North American economy, an understanding of how markets for these commodities interact is important. This dissertation independently characterizes the price dynamics of major electricity and natural gas spot markets in North America by combining directed acyclic graphs with time series analyses. Furthermore, the dissertation explores a generalization of price difference bands associated with the law of one price. Interdependencies among 11 major electricity spot markets are examined in Chapter II using a vector autoregression model. Results suggest that the relationships between the markets vary by time. Western markets are separated from the eastern markets and the Electricity Reliability Council of Texas. At longer time horizons these separations disappear. Palo Verde is the important spot market in the west for price discovery. Southwest Power Pool is the dominant market in Eastern Interconnected System for price discovery. Interdependencies among eight major natural gas spot markets are investigated using a vector error correction model and the Greedy Equivalence Search Algorithm in Chapter III. Findings suggest that the eight price series are tied together through sixlong-run cointegration relationships, supporting the argument that the natural gas market has developed into a single integrated market in North America since deregulation. Results indicate that price discovery tends to occur in the excess consuming regions and move to the excess producing regions. Across North America, the U.S. Midwest region, represented by the Chicago spot market, is the most important for price discovery. The Ellisburg-Leidy Hub in Pennsylvania and Malin Hub in Oregon are important for eastern and western markets. In Chapter IV, a threshold vector error correction model is applied to the natural gas markets to examine nonlinearities in adjustments to the law of one price. Results show that there are nonlinear adjustments to the law of one price in seven pair-wise markets. Four alternative cases for the law of one price are presented as a theoretical background. A methodology is developed for finding a threshold cointegration model that accounts for seasonality in the threshold levels. Results indicate that dynamic threshold effects vary depending on geographical location and whether the markets are excess producing or excess consuming markets.

Park, Haesun

2005-08-01T23:59:59.000Z

269

Potential Vorticity and Layer Thickness Variations in the Flow around Jupiter's Great Red Spot and White Oval BC  

Science Conference Proceedings (OSTI)

Layer thickness variations in Jupiter's atmosphere are investigated by treating potential vorticity as a conserved tracer. Starting with the horizontal velocity field measured from Voyager images, fluid trajectories around the Great Red Spot (GRS)...

Timothy E. Dowling; Andrew P. Ingersoll

1988-04-01T23:59:59.000Z

270

Measurement of focal spot size with slit camera using computed radiography and flat-panel based digital detectors  

Science Conference Proceedings (OSTI)

The purpose of this study was to evaluate the use of digital x-ray imagingdetectors for the measurement of diagnostic x-ray tube focal spot size using a slit camera. Slit cameraimages of two focal spots for a radiographicx-ray tube were acquired with direct-exposure film (DF) (as specified by the National Electrical Manufacturers Association [NEMA] Standards Publication No. XR 5

Xiujiang J. Rong; Kerry T. Krugh; S. Jeff Shepard; William R. Geiser

2003-01-01T23:59:59.000Z

271

A First-Passage Kinetic Monte Carlo algorithm for complex diffusion-reaction systems  

Science Conference Proceedings (OSTI)

We develop an asynchronous event-driven First-Passage Kinetic Monte Carlo (FPKMC) algorithm for continuous time and space systems involving multiple diffusing and reacting species of spherical particles in two and three dimensions. The FPKMC algorithm ... Keywords: Asynchronous algorithms, Diffusion-reaction, First-passage, Kinetic Monte Carlo

Aleksandar Donev; Vasily V. Bulatov; Tomas Oppelstrup; George H. Gilmer; Babak Sadigh; Malvin H. Kalos

2010-05-01T23:59:59.000Z

272

Sequential Monte Carlo for Bayesian sequentially designed experiments for discrete data  

Science Conference Proceedings (OSTI)

In this paper we present a sequential Monte Carlo algorithm for Bayesian sequential experimental design applied to generalised non-linear models for discrete data. The approach is computationally convenient in that the information of newly observed data ... Keywords: Clinical trials, Generalised linear model, Generalised non-linear model, Sequential Monte Carlo, Sequential design, Target stimulus

Christopher C. Drovandi; James M. Mcgree; Anthony N. Pettitt

2013-01-01T23:59:59.000Z

273

Monte Carlo modeling of spin FETs controlled by spin-orbit interaction  

Science Conference Proceedings (OSTI)

A method for Monte Carlo simulation of 2D spin-polarized electron transport in III-V semiconductor heterojunction (FETs) is presented. In the simulation, the dynamics of the electrons in coordinate and momentum space is treated semiclassically. The density ... Keywords: FET, Monte Carlo, spin orbit, spintronics

Min Shen; Semion Saikin; Ming-C. Cheng; Vladimir Privman

2004-05-01T23:59:59.000Z

274

Asymptotic diffusion limit of the symbolic Monte-Carlo method for the transport equation  

Science Conference Proceedings (OSTI)

We use asymptotic analysis to study the diffusion limit of the Symbolic Implicit Monte-Carlo (SIMC) method for the transport equation. For standard SIMC with piecewise constant basis functions, we demonstrate mathematically that the solution converges ... Keywords: Monte-Carlo method, radiative transfer

J.-F. Clouët; G. Samba

2004-03-01T23:59:59.000Z

275

Using Monte-Carlo simulation for risk assessment: application to occupational exposure during remediation works  

Science Conference Proceedings (OSTI)

The aim of this study was to apply the Monte-Carlo techniques to develop a probabilistic risk assessment. The risk resulting from the occupational exposure during the remediation activities of a uranium tailings disposal, in an abandoned uranium mining ... Keywords: Monte Carlo simulation, occupational exposure, risk and dose assessment, uranium tailings disposal

M. L. Dinis; A. Fiúza

2010-08-01T23:59:59.000Z

276

Methods for coupling radiation, ion, and electron energies in grey Implicit Monte Carlo  

Science Conference Proceedings (OSTI)

We present three methods for extending the Implicit Monte Carlo (IMC) method to treat the time-evolution of coupled radiation, electron, and ion energies. The first method splits the ion and electron coupling and conduction from the standard IMC radiation-transport ... Keywords: Implicit Monte Carlo, Thermal radiation transport, Three-temperature model

T. M. Evans; J. D. Densmore

2007-08-01T23:59:59.000Z

277

A comparison of generalized hybrid Monte Carlo methods with and without momentum flip  

Science Conference Proceedings (OSTI)

The generalized hybrid Monte Carlo (GHMC) method combines Metropolis corrected constant energy simulations with a partial random refreshment step in the particle momenta. The standard detailed balance condition requires that momenta are negated upon ... Keywords: Langevin dynamics, Molecular dynamics, Monte Carlo methods, Sampling

Elena Akhmatskaya; Nawaf Bou-Rabee; Sebastian Reich

2009-04-01T23:59:59.000Z

278

An efficient, robust, domain-decomposition algorithm for particle Monte Carlo  

Science Conference Proceedings (OSTI)

A previously described algorithm [T.A. Brunner, T.J. Urbatsch, T.M. Evans, N.A. Gentile, Comparison of four parallel algorithms for domain decomposed implicit Monte Carlo, Journal of Computational Physics 212 (2) (2006) 527-539] for doing domain decomposed ... Keywords: Monte Carlo methods, Neutron transport, Parallel computation, Radiative transfer

Thomas A. Brunner; Patrick S. Brantley

2009-06-01T23:59:59.000Z

279

Multi-Determinant Wave-functions in Quantum Monte Carlo  

E-Print Network (OSTI)

Quantum Monte Carlo (QMC) methods have received considerable attention over the last decades due to their great promise for providing a direct solution to the many-body Schrodinger equation in electronic systems. Thanks to their low scaling with number of particles, QMC methods present a compelling competitive alternative for the accurate study of large molecular systems and solid state calculations. In spite of such promise, the method has not permeated the quantum chemistry community broadly, mainly because of the fixed-node error, which can be large and whose control is difficult. In this Perspective, we present a systematic application of large scale multi-determinant expansions in QMC, and report on its impressive performance with first row dimers and the 55 molecules of the G1 test set. We demonstrate the potential of this strategy for systematically reducing the fixed-node error in the wave function and for achieving chemical accuracy in energy predictions. When compared to traditional quantum chemistr...

Morales, M A; Clark, B K; Kim, J; Scuseria, G; 10.1021/ct3003404

2013-01-01T23:59:59.000Z

280

Optimization of Monte Carlo transport simulations in stochastic media  

Science Conference Proceedings (OSTI)

This paper presents an accurate and efficient approach to optimize radiation transport simulations in a stochastic medium of high heterogeneity, like the Very High Temperature Gas-cooled Reactor (VHTR) configurations packed with TRISO fuel particles. Based on a fast nearest neighbor search algorithm, a modified fast Random Sequential Addition (RSA) method is first developed to speed up the generation of the stochastic media systems packed with both mono-sized and poly-sized spheres. A fast neutron tracking method is then developed to optimize the next sphere boundary search in the radiation transport procedure. In order to investigate their accuracy and efficiency, the developed sphere packing and neutron tracking methods are implemented into an in-house continuous energy Monte Carlo code to solve an eigenvalue problem in VHTR unit cells. Comparison with the MCNP benchmark calculations for the same problem indicates that the new methods show considerably higher computational efficiency. (authors)

Liang, C.; Ji, W. [Dept. of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Inst., 110 8th street, Troy, NY (United States)

2012-07-01T23:59:59.000Z

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.


281

Monte Carlo Simulation Tool Installation and Operation Guide  

Science Conference Proceedings (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

282

Correlated wavefunction quantum Monte Carlo approach to solids  

DOE Green Energy (OSTI)

A method for calculating the electronic and structural properties of solids using correlated wavefunctions together with quantum Monte Carlo techniques is described. The approach retains the exact Coulomb interaction between the electrons and employs a many-electron wavefunction of the Jastrow-Slater form. Several examples are given to illustrate the utility of the method. Topics discussed include the cohesive properties of bulk semiconductors, the magnetic-field- induced Wigner crystal in two dimensions, and the magnetic structure of bcc hydrogen. Landau level mixing is shown to be important in determining the transition between the fractional quantum Hall liquid and the Wigner crystal. Information on electron correlations such as the pair correlation functions which are not accessible to one- electron theories is also obtained. 24 refs, 5 figs, 1 tab.

Louie, S.G.

1992-10-01T23:59:59.000Z

283

The Quantum Energy Density: Improved Efficiency for Quantum Monte Carlo  

E-Print Network (OSTI)

We establish a physically meaningful representation of a quantum energy density for use in Quantum Monte Carlo calculations. The energy density operator, defined in terms of Hamiltonian components and density operators, returns the correct Hamiltonian when integrated over a volume containing a cluster of particles. This property is demonstrated for a helium-neon "gas," showing that atomic energies obtained from the energy density correspond to eigenvalues of isolated systems. The formation energies of defects or interfaces are typically calculated as total energy differences. Using a model of delta-doped silicon (where dopant atoms form a thin plane) we show how interfacial energies can be calculated more efficiently with the energy density, since the region of interest is small. We also demonstrate how the energy density correctly transitions to the bulk limit away from the interface where the correct energy is obtainable from a separate total energy calculation.

Krogel, Jaron T; Kim, Jeongnim; Ceperley, David M

2013-01-01T23:59:59.000Z

284

Bayesian Inference in Monte-Carlo Tree Search  

E-Print Network (OSTI)

Monte-Carlo Tree Search (MCTS) methods are drawing great interest after yielding breakthrough results in computer Go. This paper proposes a Bayesian approach to MCTS that is inspired by distributionfree approaches such as UCT [13], yet significantly differs in important respects. The Bayesian framework allows potentially much more accurate (Bayes-optimal) estimation of node values and node uncertainties from a limited number of simulation trials. We further propose propagating inference in the tree via fast analytic Gaussian approximation methods: this can make the overhead of Bayesian inference manageable in domains such as Go, while preserving high accuracy of expected-value estimates. We find substantial empirical outperformance of UCT in an idealized bandit-tree test environment, where we can obtain valuable insights by comparing with known ground truth. Additionally we rigorously prove on-policy and off-policy convergence of the proposed methods.

Tesauro, Gerald; Segal, Richard

2012-01-01T23:59:59.000Z

285

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

Science Conference Proceedings (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

286

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

Science Conference Proceedings (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

287

Soci t d exploitation du parc olien de Mont d H z cques SARL | Open Energy  

Open Energy Info (EERE)

Soci t d exploitation du parc olien de Mont d H z cques SARL Soci t d exploitation du parc olien de Mont d H z cques SARL Jump to: navigation, search Name Société d'exploitation du parc éolien de Mont d'Hézècques SARL Place Madrid, Spain Sector Wind energy Product Special purpose vehicle for French wind farm project development. References Société d'exploitation du parc éolien de Mont d'Hézècques SARL[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Société d'exploitation du parc éolien de Mont d'Hézècques SARL is a company located in Madrid, Spain . References ↑ "[ Société d'exploitation du parc éolien de Mont d'Hézècques SARL]" Retrieved from "http://en.openei.org/w/index.php?title=Soci_t_d_exploitation_du_parc_olien_de_Mont_d_H_z_cques_SARL&oldid=351211

288

Quantum Monte Carlo for electronic structure: Recent developments and applications  

DOE Green Energy (OSTI)

Quantum Monte Carlo (QMC) methods have been found to give excellent results when applied to chemical systems. The main goal of the present work is to use QMC to perform electronic structure calculations. In QMC, a Monte Carlo simulation is used to solve the Schroedinger equation, taking advantage of its analogy to a classical diffusion process with branching. In the present work the author focuses on how to extend the usefulness of QMC to more meaningful molecular systems. This study is aimed at questions concerning polyatomic and large atomic number systems. The accuracy of the solution obtained is determined by the accuracy of the trial wave function`s nodal structure. Efforts in the group have given great emphasis to finding optimized wave functions for the QMC calculations. Little work had been done by systematically looking at a family of systems to see how the best wave functions evolve with system size. In this work the author presents a study of trial wave functions for C, CH, C{sub 2}H and C{sub 2}H{sub 2}. The goal is to study how to build wave functions for larger systems by accumulating knowledge from the wave functions of its fragments as well as gaining some knowledge on the usefulness of multi-reference wave functions. In a MC calculation of a heavy atom, for reasonable time steps most moves for core electrons are rejected. For this reason true equilibration is rarely achieved. A method proposed by Batrouni and Reynolds modifies the way the simulation is performed without altering the final steady-state solution. It introduces an acceleration matrix chosen so that all coordinates (i.e., of core and valence electrons) propagate at comparable speeds. A study of the results obtained using their proposed matrix suggests that it may not be the optimum choice. In this work the author has found that the desired mixing of coordinates between core and valence electrons is not achieved when using this matrix. A bibliography of 175 references is included.

Rodriguez, M.M.S. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States). Chemical Sciences Div.

1995-04-01T23:59:59.000Z

289

Grain-Scale Simulations of Hot-Spot Initiation for Shocked TATB  

DOE Green Energy (OSTI)

High-explosive (HE) material consists of large-sized grains with micron-sized embedded impurities and pores. Under various mechanical/thermal insults, these pores collapse generating high-temperature regions leading to ignition. A computational study has been performed to investigate the mechanisms of pore collapse and hot spot initiation in TATB crystals, employing the thermohydrodynamics arbitrary-Lagrange-Eulerian code ALE3D. This initial study includes non-reactive dynamics to isolate the thermal and hydrodynamical effects. Two-dimensional high-resolution large-scale meso-scale simulations have been undertaken. We study an axisymmetric configuration for pore radii ranging from 0.5 to 2{micro}m, with initial shock pressures in the range from 3 to 11 GPa. A Mie-Gruneisen Equation of State (EOS) model is used for TATB, and includes a constant yield strength and shear modulus; while the air in the pore invokes a Livermore Equation of State (LEOS) model. The parameter space is systematically studied by considering various shock strengths, pore diameters and material properties. We find that thermal diffusion from the collapsed pores has an important effect in generating high-temperature hot spots in the TATB.

Najjar, F; Howard, W; Fried, L

2009-07-31T23:59:59.000Z

290

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

Science Conference Proceedings (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

291

Monte Carlo simulations for generic granite repository studies  

SciTech Connect

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

292

Non-analog Monte Carlo estimators for radiation momentum deposition  

SciTech Connect

The standard method for calculating radiation momentum deposition in Monte Carlo simulations is the analog estimator, which tallies the change in a particle's momentum at each interaction with the matter. Unfortunately, the analog estimator can suffer from large amounts of statistical error. In this paper, we present three new non-analog techniques for estimating momentum deposition. Specifically, we use absorption, collision, and track-length estimators to evaluate a simple integral expression for momentum deposition that does not contain terms that can cause large amounts of statistical error in the analog scheme. We compare our new non-analog estimators to the analog estimator with a set of test problems that encompass a wide range of material properties and both isotropic and anisotropic scattering. In nearly all cases, the new non-analog estimators outperform the analog estimator. The track-length estimator consistently yields the highest performance gains, improving upon the analog-estimator figure of merit by factors of up to two orders of magnitude.

Densmore, Jeffery D [Los Alamos National Laboratory; Hykes, Joshua M [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

293

Reduced Variance for Material Sources in Implicit Monte Carlo  

SciTech Connect

Implicit Monte Carlo (IMC), a time-implicit method due to Fleck and Cummings, is used for simulating supernovae and inertial confinement fusion (ICF) systems where x-rays tightly and nonlinearly interact with hot material. The IMC algorithm represents absorption and emission within a timestep as an effective scatter. Similarly, the IMC time-implicitness splits off a portion of a material source directly into the radiation field. We have found that some of our variance reduction and particle management schemes will allow large variances in the presence of small, but important, material sources, as in the case of ICF hot electron preheat sources. We propose a modification of our implementation of the IMC method in the Jayenne IMC Project. Instead of battling the sampling issues associated with a small source, we bypass the IMC implicitness altogether and simply deterministically update the material state with the material source if the temperature of the spatial cell is below a user-specified cutoff. We describe the modified method and present results on a test problem that show the elimination of variance for small sources.

Urbatsch, Todd J. [Los Alamos National Laboratory

2012-06-25T23:59:59.000Z

294

Monte Carlo Simulations of Cosmic Rays Hadronic Interactions  

Science Conference Proceedings (OSTI)

This document describes the construction and results of the MaCoR software tool, developed to model the hadronic interactions of cosmic rays with different geometries of materials. The ubiquity of cosmic radiation in the environment results in the activation of stable isotopes, referred to as cosmogenic activities. The objective is to use this application in conjunction with a model of the MAJORANA DEMONSTRATOR components, from extraction to deployment, to evaluate cosmogenic activation of such components before and after deployment. The cosmic ray showers include several types of particles with a wide range of energy (MeV to GeV). It is infeasible to compute an exact result with a deterministic algorithm for this problem; Monte Carlo simulations are a more suitable approach to model cosmic ray hadronic interactions. In order to validate the results generated by the application, a test comparing experimental muon flux measurements and those predicted by the application is presented. The experimental and simulated results have a deviation of 3%.

Aguayo Navarrete, Estanislao; Orrell, John L.; Kouzes, Richard T.

2011-04-01T23:59:59.000Z

295

Numerical study of error propagation in Monte Carlo depletion simulations  

Science Conference Proceedings (OSTI)

Improving computer technology and the desire to more accurately model the heterogeneity of the nuclear reactor environment have made the use of Monte Carlo depletion codes more attractive in recent years, and feasible (if not practical) even for 3-D depletion simulation. However, in this case statistical uncertainty is combined with error propagating through the calculation from previous steps. In an effort to understand this error propagation, a numerical study was undertaken to model and track individual fuel pins in four 17 x 17 PWR fuel assemblies. By changing the code's initial random number seed, the data produced by a series of 19 replica runs was used to investigate the true and apparent variance in k{sub eff}, pin powers, and number densities of several isotopes. While this study does not intend to develop a predictive model for error propagation, it is hoped that its results can help to identify some common regularities in the behavior of uncertainty in several key parameters. (authors)

Wyant, T.; Petrovic, B. [Nuclear and Radiological Engineering, Georgia Inst. of Technology, 770 State Street, Atlanta, GA 30332-0745 (United States)

2012-07-01T23:59:59.000Z

296

Gas reservoir sweet spot detection and delineation in Rocky Mountain laramide basins. Topical report, May 1993-March 1996  

SciTech Connect

The determination of the position and configuration of the pressure boundary between normal and anomalously pressured regimes, and the detection and delineation of porosity/permeability `sweet spots` below this boundary are the two most important elements in exploring for basin-center or deep-basin gas in Rocky Mountain Laramide Basins. These two exploration elements from the basis for a new exploration paradigm. To utilize this new paradigm, the following tasks need to be included in the exploration strategy: (1) determine the position of the pressure boundary; (2) evaluate the three-dimensional aspects of the pressure boundary surface; (3) determine which depositional facies has the greatest potential for enhances storage capacity and deliverability below the pressure boundary; (4) document the determinative factors that control sweet spot development in the targeted lithofacies; and (5) detect and delineate sweet spots using 2-D and 3-D models of eletric log responses and seismic data.

Surdam, R.C.; Iverson, W.O.; Yin, P.

1995-10-01T23:59:59.000Z

297

Mountain Waves over Mont Blanc: Influence of a Stagnant Boundary Layer  

Science Conference Proceedings (OSTI)

A stationary mountain wave, embedded in southwesterly flow over Mont Blanc in the Alps, was observed simultaneously by three research aircraft and three types of remote sensing: GPS dropsondes, airborne light detecting and ranging (lidar), and ...

Ronald B. Smith; Steven Skubis; James D. Doyle; Adrian S. Broad; Christoph Kiemle; Hans Volkert

2002-07-01T23:59:59.000Z

298

MERADGEN: Monte Carlo generator for the simulation of radiative events in polarized Moller scattering  

SciTech Connect

The Monte Carlo generator MERADGEN for the simulation of QED radiative events in polarized Moller scattering has been developed. Analytical integration wherever it is possible provides rather fast generation. Some numerical tests and histograms are presented.

Andrei Afanasev; Eugene Chudakov; Alexander Ilyichev; Vladimir Zykunov

2006-04-04T23:59:59.000Z

299

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

300

Remote Sounding of High Clouds. III: Monte Carlo Calculations of Multiple-Scattered Lidar Returns  

Science Conference Proceedings (OSTI)

Monte Carlo calculations of multiple-scattered contributions to the total energy received in a lidar beam have been made for a representative cirrus ice-cloud scattering phase function. The phase function is varied arbitrarily near the back ...

C. M. R. Platt

1981-01-01T23:59:59.000Z

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.


301

Nonlinear Parameter Estimation: Comparison of an Ensemble Kalman Smoother with a Markov Chain Monte Carlo Algorithm  

Science Conference Proceedings (OSTI)

This paper explores the temporal evolution of cloud microphysical parameter uncertainty using an idealized 1D model of deep convection. Model parameter uncertainty is quantified using a Markov chain Monte Carlo (MCMC) algorithm. A new form of the ...

Derek J. Posselt; Craig H. Bishop

2012-06-01T23:59:59.000Z

302

Time-domain non-Monte Carlo noise simulation for nonlinear dynamic circuits with arbitrary excitations  

Science Conference Proceedings (OSTI)

A new, time-domain, non-Monte Carlo method for computer simulation of electrical noise in nonlinear dynamic circuits with arbitrary excitations is presented. This time-domain noise simulation ...

Alper Demir; Edward W. Y. Liu; Alberto L. Sangiovanni-Vincentelli

1994-11-01T23:59:59.000Z

303

Clustering and Short-Range Orer in Fe-Cr Alloys: A Monte Carlo Study  

Science Conference Proceedings (OSTI)

May 1, 2007 ... Clustering and Short-Range Orer in Fe-Cr Alloys: A Monte Carlo Study by Mikhail Lavrentiev, Duc Nguyen-Manh, Sergei Dudarev, Ralf Drautz, ...

304

Estimation of Wind Speed Distribution Using Markov Chain Monte Carlo Techniques  

Science Conference Proceedings (OSTI)

The Weibull distribution is the most commonly used statistical distribution for describing wind speed data. Maximum likelihood has traditionally been the main method of estimation for Weibull parameters. In this paper, Markov chain Monte Carlo ...

Wan-Kai Pang; Jonathan J. Forster; Marvin D. Troutt

2001-08-01T23:59:59.000Z

305

A Monte Carlo Approach To Generator Portfolio Planning And Carbon Emissions  

Open Energy Info (EERE)

Monte Carlo Approach To Generator Portfolio Planning And Carbon Emissions Monte Carlo Approach To Generator Portfolio Planning And Carbon Emissions Assessments Of Systems With Large Penetrations Of Variable Renewables Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Monte Carlo Approach To Generator Portfolio Planning And Carbon Emissions Assessments Of Systems With Large Penetrations Of Variable Renewables Details Activities (0) Areas (0) Regions (0) Abstract: A new generator portfolio planning model is described that is capable of quantifying the carbon emissions associated with systems that include very high penetrations of variable renewables. The model combines a deterministic renewable portfolio planning module with a Monte Carlo simulation of system operation that determines the expected least-cost

306

PyMercury: Interactive Python for the Mercury Monte Carlo Particle Transport Code  

SciTech Connect

Monte Carlo particle transport applications are often written in low-level languages (C/C++) for optimal performance on clusters and supercomputers. However, this development approach often sacrifices straightforward usability and testing in the interest of fast application performance. To improve usability, some high-performance computing applications employ mixed-language programming with high-level and low-level languages. In this study, we consider the benefits of incorporating an interactive Python interface into a Monte Carlo application. With PyMercury, a new Python extension to the Mercury general-purpose Monte Carlo particle transport code, we improve application usability without diminishing performance. In two case studies, we illustrate how PyMercury improves usability and simplifies testing and validation in a Monte Carlo application. In short, PyMercury demonstrates the value of interactive Python for Monte Carlo particle transport applications. In the future, we expect interactive Python to play an increasingly significant role in Monte Carlo usage and testing.

Iandola, F N; O'Brien, M J; Procassini, R J

2010-11-29T23:59:59.000Z

307

A NEW MONTE CARLO METHOD FOR TIME-DEPENDENT NEUTRINO RADIATION TRANSPORT  

Science Conference Proceedings (OSTI)

Monte Carlo approaches to radiation transport have several attractive properties such as simplicity of implementation, high accuracy, and good parallel scaling. Moreover, Monte Carlo methods can handle complicated geometries and are relatively easy to extend to multiple spatial dimensions, which makes them potentially interesting in modeling complex multi-dimensional astrophysical phenomena such as core-collapse supernovae. The aim of this paper is to explore Monte Carlo methods for modeling neutrino transport in core-collapse supernovae. We generalize the Implicit Monte Carlo photon transport scheme of Fleck and Cummings and gray discrete-diffusion scheme of Densmore et al. to energy-, time-, and velocity-dependent neutrino transport. Using our 1D spherically-symmetric implementation, we show that, similar to the photon transport case, the implicit scheme enables significantly larger timesteps compared with explicit time discretization, without sacrificing accuracy, while the discrete-diffusion method leads to significant speed-ups at high optical depth. Our results suggest that a combination of spectral, velocity-dependent, Implicit Monte Carlo and discrete-diffusion Monte Carlo methods represents a robust approach for use in neutrino transport calculations in core-collapse supernovae. Our velocity-dependent scheme can easily be adapted to photon transport.

Abdikamalov, Ernazar; Ott, Christian D.; O'Connor, Evan [TAPIR, California Institute of Technology, MC 350-17, 1200 E California Blvd., Pasadena, CA 91125 (United States); Burrows, Adam; Dolence, Joshua C. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Loeffler, Frank; Schnetter, Erik, E-mail: abdik@tapir.caltech.edu [Center for Computation and Technology, Louisiana State University, 216 Johnston Hall, Baton Rouge, LA 70803 (United States)

2012-08-20T23:59:59.000Z

308

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

SciTech Connect

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; Peplow, Douglas E. [ORNL; Peterson, Joshua L [ORNL; Grove, Robert E [ORNL

2013-01-01T23:59:59.000Z

309

A new class of accelerated kinetic Monte Carlo algorithms  

Science Conference Proceedings (OSTI)

Kinetic (aka dynamic) Monte Carlo (KMC) is a powerful method for numerical simulations of time dependent evolution applied in a wide range of contexts including biology, chemistry, physics, nuclear sciences, financial engineering, etc. Generally, in a KMC the time evolution takes place one event at a time, where the sequence of events and the time intervals between them are selected (or sampled) using random numbers. While details of the method implementation vary depending on the model and context, there exist certain common issues that limit KMC applicability in almost all applications. Among such is the notorious 'flicker problem' where the same states of the systems are repeatedly visited but otherwise no essential evolution is observed. In its simplest form the flicker problem arises when two states are connected to each other by transitions whose rates far exceed the rates of all other transitions out of the same two states. In such cases, the model will endlessly hop between the two states otherwise producing no meaningful evolution. In most situation of practical interest, the trapping cluster includes more than two states making the flicker somewhat more difficult to detect and to deal with. Several methods have been proposed to overcome or mitigate the flicker problem, exactly [1-3] or approximately [4,5]. Of the exact methods, the one proposed by Novotny [1] is perhaps most relevant to our research. Novotny formulates the problem of escaping from a trapping cluster as a Markov system with absorbing states. Given an initial state inside the cluster, it is in principle possible to solve the Master Equation for the time dependent probabilities to find the walker in a given state (transient or absorbing) of the cluster at any time in the future. Novotny then proceeds to demonstrate implementation of his general method to trapping clusters containing the initial state plus one or two transient states and all of their absorbing states. Similar methods have been subsequently proposed in [refs] but applied in a different context. The most serious deficiency of the earlier methods is that size of the trapping cluster size is fixed and often too small to bring substantial simulation speedup. Furthermore, the overhead associated with solving for the probability distribution on the trapping cluster sometimes makes such simulations less efficient than the standard KMC. Here we report on a general and exact accelerated kinetic Monte Carlo algorithm generally applicable to arbitrary Markov models1. Two different implementations are attempted both based on incremental expansion of trapping sub-set of Markov states: (1) numerical solution of the Master Equation with absorbing states and (2) incremental graph reduction followed by randomization. Of the two implementations, the 2nd one performs better allowing, for the first time, to overcome trapping basins spanning several million Markov states. The new method is used for simulations of anomalous diffusion on a 2D substrate and of the kinetics of diffusive 1st order phase transformations in binary alloys. Depending on temperature and (alloy) super-saturation conditions, speedups of 3 to 7 orders of magnitude are demonstrated, with no compromise of simulation accuracy.

Bulatov, V V; Oppelstrup, T; Athenes, M

2011-11-30T23:59:59.000Z

310

In R&D, Super X-rays Mark Many Spots  

NLE Websites -- All DOE Office Websites (Extended Search)

A New Gas Loading System for Diamond Anvil Cells at GSECARS A New Gas Loading System for Diamond Anvil Cells at GSECARS Sidorowicz Named "Supervisor of the Year" SESS 2007: The School for Environmental Sciences with Synchrotrons Art and Science A Breakthrough in Interface Science APS News Archives: 2012 | 2011 | 2010 | 2009 2008 | 2007 | 2006 | 2005 2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed In R&D, Super X-rays Mark Many Spots MARCH 11, 2008 Bookmark and Share Research and Design Magazine "The Advanced Photon Source (APS) at the U.S. Dept. of Energy's Argonne National Laboratory has been kept busy of late." That's the first sentence of R&D Magazine's recent overview of research results from the APS. The article highlights "a new ultrafast synchrotron x-ray full-field phase contrast imaging technique and used it to reveal

311

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

Science Conference Proceedings (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

312

Reciprocal space mapping by spot profile analyzing low energy electron diffraction  

SciTech Connect

We present an experimental approach for the recording of two-dimensional reciprocal space maps using spot profile analyzing low energy electron diffraction (SPA-LEED). A specialized alignment procedure eliminates the shifting of LEED patterns on the screen which is commonly observed upon variation of the electron energy. After the alignment, a set of one-dimensional sections through the diffraction pattern is recorded at different energies. A freely available software tool is used to assemble the sections into a reciprocal space map. The necessary modifications of the Burr-Brown computer interface of the two Leybold and Omicron type SPA-LEED instruments are discussed and step-by-step instructions are given to adapt the SPA 4.1d software to the changed hardware. Au induced faceting of 4 deg. vicinal Si(001) is used as an example to demonstrate the technique.

Meyer zu Heringdorf, Frank-J.; Horn-von Hoegen, Michael [Institut fuer Experimentelle Physik, Universitaet Duisburg-Essen, 45117 Essen (Germany)

2005-08-15T23:59:59.000Z

313

Analytic criteria for shock ignition of fusion reactions in a central hot spot  

Science Conference Proceedings (OSTI)

Shock ignition is an inertial confinement fusion scheme where the ignition conditions are achieved in two steps. First, the DT shell is compressed at a low implosion velocity creating a central core at a low temperature and a high density. Then, a strong spherical converging shock is launched before the fuel stagnation time. It increases the central pressure and ignites the core. It is shown in this paper that this latter phase can be described analytically by using a self-similar solution to the equations of ideal hydrodynamics. A high and uniformly distributed pressure in the hot spot can be created thus providing favorable conditions for ignition. Analytic ignition criteria are obtained that relate the areal density of the compressed core with the shock velocity. The conclusions of the analytical model are confirmed in full hydrodynamic simulations.

Ribeyre, X.; Tikhonchuk, V. T.; Breil, J.; Lafon, M.; Le Bel, E. [Centre Lasers Intenses et Applications, Universite Bordeaux 1-CEA-CNRS, Talence 33405 (France)

2011-10-15T23:59:59.000Z

314

Empirical analysis of the spot market implications ofprice-elastic demand  

SciTech Connect

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

315

Empirical Analysis of the Spot Market Implications ofPrice-Responsive Demand  

SciTech Connect

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

316

The Eastern red-spotted newt Notophthalmus viridescens uses the geomagnetic field for two forms of spatial orientation: (1)  

E-Print Network (OSTI)

The Eastern red-spotted newt Notophthalmus viridescens uses the geomagnetic field for two forms also use the geomagnetic field to derive map information (Fischer et al., 2001; Phillips et al., 2002 from the geomagnetic field (Phillips and Borland, 1994). Under long- wavelength light, therefore

Phillips, John B.

317

Beam power and angle adaptation in multibeam 2.5 Gbit/s spot diffusing mobile optical wireless system  

Science Conference Proceedings (OSTI)

Mobility can induce significant signal-to-noise ratio (SNR) performance degradation in optical wireless (OW) systems based on diffuse as well as spot-diffusing configurations. Two methods (beam angle and beam power adaptation) are introduced to the design ... Keywords: beam angle adaptation, diversity receiver, optical wireless communication, transmit power adaptation

Fuad E. Alsaadi; Jaafar M. H. Elmirghani

2010-08-01T23:59:59.000Z

318

OPTIMIZATION OF THE HYSPEC DESIGN USING MONTE CARLO SIMULATIONS.  

DOE Green Energy (OSTI)

HYSPEC is a direct geometry spectrometer to be installed at the SNS [1] on beamline 14B where it will view a cryogenic coupled hydrogen moderator, The ''hybrid'' design combines time-of-flight spectroscopy with focusing Bragg optics to provide a high monochromatic flux on small single crystal samples, with a very low background at an extended detector bank. The instrument is optimized for an incident energy range of 3-90meV. It will have a medium energy resolution (2-10%) and will provide a flux on sample of the order of 10{sup 6}-10{sup 7} neutrons/s-cm{sup 2}. The spectrometer will be located in a satellite building outside the SNS experimental hall at the end of a 35m curved supermirror guide. A straight-slotted Fermi chopper will be used to monochromate the neutron beam and to determine the burst width. The 15cm high, 4cm wide beam will be focused onto a 2cm by 2cm area at the sample position using Bragg reflection from one of two crystal arrays. For unpolarized neutron studies these will be Highly Oriented Pyrolitic graphite crystals while for polarized neutron studies these will be replaced with Heusler alloy crystals. These focusing crystal arrays will be placed in a drum shield similar to those used for triple axis spectrometers. Hyspec will have a movable detector bank housing 160 position sensitive detectors. This detector bank will pivot about the sample axis. It will have a radius of 4.5m, a horizontal range of 60{sup o}, and a vertical range of {+-} 7.5{sup o}. In order to reduce background at the detector bank both a curved guide and a T0 chopper will be used. A bank of 20 supermirror bender polarization analyzers [2] will be used to spatially separate the polarized neutrons in the scattered beam so that both scattered neutron spin states can be measured simultaneously. The results of Monte Carlo simulations performed to optimize the instrument design will be discussed.

GHOSH, V.J.; HAGEN, M.E.; LEONHARDT, W.J.; ZALIZNYAK, I.; SHAPIRO, S.M.; PASSELL, L.

2005-04-25T23:59:59.000Z

319

LA COLONISATION DE L'AMAZONIE FACE AU DEVELOPPEMENT DURABLE : L'EXEMPLE DU BARRAGE DE BELO MONTE  

E-Print Network (OSTI)

LA COLONISATION DE L'AMAZONIE FACE AU DEVELOPPEMENT DURABLE : L'EXEMPLE DU BARRAGE DE BELO MONTE projets phare du programme Avança Brasil, le barrage de Belo Monte, barrage que nous replaçons dans l on the detailed study of one of the most important projcet of the Avança Brazil Program, the Belo Monte dam, we

Paris-Sud XI, Université de

320

Monte Carlo simulation of radiation heat transfer in arrays of fixed discrete surfaces using cell-to-cell photon transport  

DOE Green Energy (OSTI)

Radiation heat transfer in an array of fixed discrete surfaces is an important problem that is particularly difficult to analyze because of the nonhomogeneous and anisotropic optical properties involved. This article presents an efficient Monte Carlo method for evaluating radiation heat transfer in arrays of fixed discrete surfaces. This Monte Carlo model has been optimized to take advantage of the regular arrangement of surfaces often encountered in these arrays. Monte Carlo model predictions have been compared with analytical and experimental results.

Drost, M.K. (Pacific Northwest Lab., Richland, WA (United States)); Welty, J.R. (Oregon State Univ., Corvallis, OR (United States))

1992-08-01T23:59:59.000Z

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.


321

Use of the linear variate method of Monte Carlo for estimating uncertainty in thermal-hydraulic codes  

SciTech Connect

Thermal-hydraulic computer codes represent non-linear functions that may contain discontinuities. Monte Carlo methods are an effective means of accurately evaluating the effect of uncertainty on a nonlinear function with discontinuities, but the computational requirements of standard Monte Carlo methods may be prohibitive. The linear variate Monte Carlo method is a means of reducing the computational requirements. The linear variate method combines the linear response surface method with Monte Carlo analysis to obtain an efficient and accurate method of nonlinear uncertainty analysis. The method is applied to the power limit analysis for the Savannah River Site reactors. 7 refs., 2 figs., 3 tabs.

Kubic, W.L. Jr.; White, A.M. (Los Alamos National Lab., NM (USA); Westinghouse Savannah River Co., Aiken, SC (USA))

1989-01-01T23:59:59.000Z

322

Tests of Monte Carlo Independent Column Approximation With a Mixed-Layer Ocean Model  

NLE Websites -- All DOE Office Websites (Extended Search)

Tests of Monte Carlo Independent Column Tests of Monte Carlo Independent Column Approximation With a Mixed-Layer Ocean Model Petri Simo Järvenoja Heikki Järvinen Räisänen Finnish Meteorological Institute Figure 1. Root-mean-square sampling errors in local instant- aneous total (LW+SW) net flux at the surface and total radiative heating rate for the 1COL, CLDS, and REF approaches. Global rms values are given at the upper right hand corner of the plots. 1. Introduction The Monte Carlo Independent Column Approximation (McICA) separates the description of unresolved cloud structure from the radiative transfer solver very flexible ! unbiased with respect to ICA ! However, the radiative fluxes and heating rates contain conditional random errors ("McICA noise"). ? The topic of this poster: All previous tests of McICA

323

Tests of Monte Carlo Independent Column Approximation in the ECHAM5  

NLE Websites -- All DOE Office Websites (Extended Search)

Tests of Monte Carlo Independent Column Approximation in the ECHAM5 Tests of Monte Carlo Independent Column Approximation in the ECHAM5 Atmospheric GCM Raisanen, Petri Finnish Meteoroligical Institute Jarvenoja, Simo Finnish Meteorological Institute Jarvinen, Heikki Finnish Meteorological Institute Category: Modeling The Monte Carlo Independent Column Approximation (McICA) was recently introduced as a new approach for parametrizing broadband radiative fluxes in global climate models (GCMs). The McICA allows a flexible description of unresolved cloud structure, and it is unbiased with respect to the full ICA, but its results contain conditional random errors (i.e., noise). In this work, McICA and a stochastic cloud generator have been implemented to the Max Planck Institute for Meteorology's ECHAM5 atmospheric GCM. The

324

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

325

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

Science Conference Proceedings (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

326

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

Science Conference Proceedings (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

327

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

SciTech Connect

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

328

General purpose dynamic Monte Carlo with continuous energy for transient analysis  

SciTech Connect

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

329

HOT AND COLD SPOT COUNTS AS PROBES OF NON-GAUSSIANITY IN THE COSMIC MICROWAVE BACKGROUND  

SciTech Connect

We introduce the numbers of hot and cold spots, n{sub h} and n{sub c} , of excursion sets of the cosmic microwave background (CMB) temperature anisotropy maps as statistical observables that can discriminate different non-Gaussian models. We numerically compute them from simulations of non-Gaussian CMB temperature fluctuation maps. The first kind of non-Gaussian model we study is the local type primordial non-Gaussianity. The second kind of model has some specific form of the probability distribution function from which the temperature fluctuation value at each pixel is drawn, obtained using HEALPIX. We find the characteristic non-Gaussian deviation shapes of n{sub h} and n{sub c} , which is distinct for each of the models under consideration. We further demonstrate that n{sub h} and n{sub c} carry additional information compared to the genus, which is just their linear combination, making them valuable additions to the Minkowski Functionals in constraining non-Gaussianity.

Chingangbam, Pravabati [Indian Institute of Astrophysics, Koramangala II Block, Bangalore 560034 (India); Park, Changbom [Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 130-722 (Korea, Republic of); Yogendran, K. P. [Indian Institute for Science Education and Research, Mohali (India); Van de Weygaert, Rien, E-mail: prava@iiap.res.in, E-mail: cbp@kias.re.kr, E-mail: pattag@gmail.com, E-mail: weygaert@astro.rug.nl [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9747 AV Groningen (Netherlands)

2012-08-20T23:59:59.000Z

330

FREYA-a new Monte Carlo code for improved modeling of fission chains  

Science Conference Proceedings (OSTI)

A new simulation capability for modeling of individual fission events and chains and the transport of fission products in materials is presented. FREYA ( Fission Yield Event Yield Algorithm ) is a Monte Carlo code for generating fission events providing correlated kinematic information for prompt neutrons, gammas, and fragments. As a standalone code, FREYA calculates quantities such as multiplicity-energy, angular, and gamma-neutron energy sharing correlations. To study materials with multiplication, shielding effects, and detectors, we have integrated FREYA into the general purpose Monte Carlo code MCNP. This new tool will allow more accurate modeling of detector responses including correlations and the development of SNM detectors with increased sensitivity.

Hagmann, C A; Randrup, J; Vogt, R L

2012-06-12T23:59:59.000Z

331

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

SciTech Connect

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

332

Monte Carlo simulation of the Massachusetts Institute of Technology Research Reactor  

SciTech Connect

The three-dimensional continuous-energy MCNP Monte Carlo code is used to develop a versatile and accurate reactor physics model of the Massachusetts Institute of Technology Research Reactor 2 (MITR-2). The validation of the model against existing experimental data is presented. Core multiplication factors as well as fast neutron in-core flux measurements were used in the validation process. The agreement between the MCNP predictions and the experimentally determined values is very good, which indicates that the Monte Carlo model is correctly simulating the MITR-2.

Redmond, E.L. II; Yanch, J.C.; Harling, O.K. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Nuclear Engineering Dept.)

1994-04-01T23:59:59.000Z

333

Penalized Splines for Smooth Representation of High-dimensional Monte Carlo Datasets  

E-Print Network (OSTI)

Detector response to a high-energy physics process is often estimated by Monte Carlo simulation. For purposes of data analysis, the results of this simulation are typically stored in large multi-dimensional histograms, which can quickly become both too large to easily store and manipulate and numerically problematic due to unfilled bins or interpolation artifacts. We describe here an application of the penalized spline technique to efficiently compute B-spline representations of such tables and discuss aspects of the resulting B-spline fits that simplify many common tasks in handling tabulated Monte Carlo data in high-energy physics analysis, in particular their use in maximum-likelihood fitting.

Whitehorn, Nathan; Lafebre, Sven

2013-01-01T23:59:59.000Z

334

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

335

The IkBa/NF-kB complex has two hot spots, one at either end of the interface  

E-Print Network (OSTI)

The IkBa/NF-kB complex has two hot spots, one at either end of the interface SIMON BERGQVIST,1 of NF-kB family members via its ankyrin repeat (AR) domain. The binding affinity of IkBa with NF-kB(p50/p65) heterodimers and NF-kB(p65/65) homodimers is in the picomolar range, and in the cell

Komives, Elizabeth A.

336

Modeling of Asymmetry between Gasoline and Crude Oil Prices: A Monte Carlo Comparison  

Science Conference Proceedings (OSTI)

An Engle---Granger two-step procedure is commonly used to estimate cointegrating vectors and consequently asymmetric error-correction models. This study uses Monte Carlo methods and demonstrates that the Engle---Granger two-step method leads to biased ... Keywords: Asymmetry, Gasoline, Modeling, Oil prices

Afshin Honarvar

2010-10-01T23:59:59.000Z

337

Benchmark calculation of no-core Monte Carlo shell model in light nuclei  

E-Print Network (OSTI)

The Monte Carlo shell model is firstly applied to the calculation of the no-core shell model in light nuclei. The results are compared with those of the full configuration interaction. The agreements between them are within a few % at most.

T. Abe; P. Maris; T. Otsuka; N. Shimizu; Y. Utsuno; J. P. Vary

2011-07-09T23:59:59.000Z

338

GPU-Based Monte-Carlo Volume Raycasting Christof Rezk Salama  

E-Print Network (OSTI)

- ducing convincing images, yet flexible enough for digital productions in practice. 1 Introduction Volume can be found in the book by Engel et al. [1]. The first solely GPU-based implementations of volumeGPU-Based Monte-Carlo Volume Raycasting Christof Rezk Salama Computer Graphics Group, University

Blanz, Volker

339

State space exploration using feedback constraint generation and Monte-Carlo sampling  

Science Conference Proceedings (OSTI)

The systematic exploration of the space of all the behaviours of a software system forms the basis of numerous approaches to verification. However, existing approaches face many challenges with scalability and precision. We propose a framework for validating ... Keywords: model-checking, monte-carlo, statistical sampling, verification

Sriram Sankaranarayanan; Richard M. Chang; Guofei Jiang; Franjo Ivan?i?

2007-09-01T23:59:59.000Z

340

A Monte Carlo model for seeded atomic flows in the transition regime  

Science Conference Proceedings (OSTI)

A simple model for the numerical determination of separation effects in seeded atomic gas flows is presented. The model is based on the known possibility to provide a statistically convergent estimate of the exact solution for a linear transport equation ... Keywords: Compressible flows, Monte Carlo simulation, Multi-component flows, Numerical methods, Rarefied flows

S. Longo; P. Diomede

2009-06-01T23:59:59.000Z

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.


341

Benchmark calculation of no-core Monte Carlo shell model in light nuclei  

E-Print Network (OSTI)

The Monte Carlo shell model is firstly applied to the calculation of the no-core shell model in light nuclei. The results are compared with those of the full configuration interaction. The agreements between them are within a few % at most.

Abe, T; Otsuka, T; Shimizu, N; Utsuno, Y; Vary, J P; 10.1063/1.3584062

2011-01-01T23:59:59.000Z

342

Benchmark calculation of no-core Monte Carlo shell model in light nuclei  

SciTech Connect

The Monte Carlo shell model is firstly applied to the calculation of the no-core shell model in light nuclei. The results are compared with those of the full configuration interaction. The agreements between them are within a few % at most.

Abe, T.; Shimizu, N. [Department of Physics, the University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Maris, P.; Vary, J. P. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Otsuka, T. [Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); CNS, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); Utsuno, Y. [ASRC, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

2011-05-06T23:59:59.000Z

343

Dose verification with Monte Carlo technique for prostate brachytherapy implants with {sup 125}I sources  

SciTech Connect

The Monte Carlo technique has been implemented to generate the dose distributions in a model prostate patient, implanted with iodine-125 ({sup 125}I) brachytherapy sources. The results of these calculations are also compared with the dose distributions calculated by a commercially available treatment planning system. The comparison shows that with the source strength suggested by the Monte Carlo technique, the current clinical planning system is found to provide 100% coverage of the prostate with the prescription dose for the same implant pattern. However, the dose-volume histogram of this investigation shows that the VariSeedTM treatment planning system has a 29% and 136% larger dose coverage for the 150% and 200% isodose lines, respectively, than the Monte Carlo simulation. These differences are attributed to the oversimplification of the current planning system using the point source approximation, and also to the interseed effects from multisources that are neglected in the conventional planning systems. The results of this study provide evidence that supports the use of the Monte Carlo technique in treatment planning systems to provide accurate dose calculations in brachytherapy implants.

Zhang Hualin [Department of Radiation Medicine, University of Kentucky Medical Center, Lexington, KY (United States)]. E-mail: hualinzhang@yahoo.com; Baker, Curtis [Department of Radiation Medicine, University of Kentucky Medical Center, Lexington, KY (United States); McKinsey, Rachel [Department of Radiation Medicine, University of Kentucky Medical Center, Lexington, KY (United States); Meigooni, Ali [Department of Radiation Medicine, University of Kentucky Medical Center, Lexington, KY (United States)

2005-06-30T23:59:59.000Z

344

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

345

Evaluating Simulation Heuristics in Monte?Carlo Tree Search and its Application to a Production Scheduling  

Science Conference Proceedings (OSTI)

This paper reports simulation heuristics of Monte?Carlo Tree Search (MCTS) and shows an application example. MCTS introduced by Coulom is a best?first search where pseudorandom simulations guide the solution of problem. Recent improvements on MCTS have produced strong computer Go program

Shimpei Matsumoto; Kosuke Kato; Noriaki Hirosue; Hiroaki Ishii

2010-01-01T23:59:59.000Z

346

Monte Carlo simulation of solar radiation in maize canopies and its visualization  

Science Conference Proceedings (OSTI)

The spatial distribution of solar radiation casts important influences on eco-physiological functions of plant canopies. A simulation model of the three-dimensional of direct and indirect solar radiation in real maize canopies is developed from measured ... Keywords: Monte Carlo algorithm, plant canopy, radiosity, ray tracing, three-dimensional distribution

Zhang Yuan; Lao Cai-lian; Lee Bao-Guo; Chen Yan; Guo Yan; Wang Xi-ping; Ma Yun-tao; Zhao Ming

2007-04-01T23:59:59.000Z

347

Generation reliability assessment in power markets using Monte Carlo simulation and soft computing  

Science Conference Proceedings (OSTI)

Deregulation policy has caused some changes in the concepts of power systems reliability assessment and enhancement. In the present research, generation reliability is considered, and a method for its assessment is proposed using intelligent systems. ... Keywords: Generation reliability, Intelligent systems, Monte Carlo simulation, Power pool market

H. Haroonabadi; M. -R. Haghifam

2011-12-01T23:59:59.000Z

348

Is the Standard Monte Carlo Power Iteration Approach the Wrong Approach? Part 2  

Science Conference Proceedings (OSTI)

The recent work 'Is the Standard Monte Carlo Power Iteration Approach the Wrong Approach?' speculated that the second eigenfunction could be built using essentially the same 'building brick' approach that obtained the first eigenfunction in LA-UR-12-21928. This note shows that the speculation was at least partially correct, but not complete.

Booth, Thomas E. [Los Alamos National Laboratory

2012-07-11T23:59:59.000Z

349

A Monte Carlo Assessment of Uncertainties in Heavy Precipitation Frequency Variations  

Science Conference Proceedings (OSTI)

A Monte Carlo analysis was used to assess the effects of missing data and limited station density on the uncertainties in the temporal variations of U.S. heavy precipitation event frequencies observed for 1895–2004 using data from the U.S. ...

Kenneth E. Kunkel; Thomas R. Karl; David R. Easterling

2007-10-01T23:59:59.000Z

350

Monte Carlo simulation-based algorithms for estimating the reliability of mobile agent-based systems  

Science Conference Proceedings (OSTI)

In this paper, we propose two algorithms for estimating the task route reliability of mobile agent-based systems (MABS), which are based on the conditions of the underlying computer network. In addition, we propose a third algorithm for generating a ... Keywords: Algorithms, Mobile agents, Monte Carlo simulation, Random walk, Reliability

Mosaab Daoud; Qusay H. Mahmoud

2008-01-01T23:59:59.000Z

351

Monte Carlo Study of the Scattering Error of a Quartz Reflective Absorption Tube  

Science Conference Proceedings (OSTI)

A Monte Carlo model was used to study the scattering error of an absorption meter with a divergent light beam and a limited acceptance angle of the receiver. Reflections at both ends of the tube were taken into account. Calculations of the effect ...

Jacek Piskozub; Piotr J. Flatau; J. V. Ronald Zaneveld

2001-03-01T23:59:59.000Z

352

Monte Carlo Estimation of Time Mismatch Effect in an OFDM EER Architecture  

E-Print Network (OSTI)

Monte Carlo Estimation of Time Mismatch Effect in an OFDM EER Architecture J-F.Bercher, A.Diet, C technique due to non-linearities of the power amplification operation. EER architecture can be used to solve-linearities in the radio- frequency transmitter. Linearization methods are necessary. EER (Envelope Elimination

Baudoin, Geneviève

353

A Mersenne Twister Hardware Implementation for the Monte Carlo Localization Algorithm  

Science Conference Proceedings (OSTI)

Mobile robot localization is the problem of estimating a robot position based on sensor data and a map of the environment. One of the most used methods to address this problem is based on the Monte Carlo Localization (MCL) algorithm, which is a sample ... Keywords: Embedded mobile robotics, FPGA, Mersenne twister, Particle filter

Vanderlei Bonato; Bruno F. Mazzotti; Marcio Merino Fernandes; Eduardo Marques

2013-01-01T23:59:59.000Z

354

Acceleration of Monte Carlo Criticality Calculations Using Deterministic-Based Starting Sources  

SciTech Connect

A new automatic approach that uses approximate deterministic solutions for providing the starting fission source for Monte Carlo eigenvalue calculations was evaluated in this analysis. By accelerating the Monte Carlo source convergence and decreasing the number of cycles that has to be skipped before the tallies estimation, this approach was found to increase the efficiency of the overall simulation, even with the inclusion of the extra computational time required by the deterministic calculation. This approach was also found to increase the reliability of the Monte Carlo criticality calculations of loosely coupled systems because the use of the better starting source reduces the likelihood of producing an undersampled k{sub eff} due to the inadequate source convergence. The efficiency improvement was demonstrated using two of the standard test problems devised by the OECD/NEA Expert Group on Source Convergence in Criticality-Safety Analysis to measure the source convergence in Monte Carlo criticality calculations. For a fixed uncertainty objective, this approach increased the efficiency of the overall simulation by factors between 1.2 and 3 depending on the difficulty of the source convergence in these problems. The reliability improvement was demonstrated in a modified version of the 'k{sub eff} of the world' problem that was specifically designed to demonstrate the limitations of the current Monte Carlo power iteration techniques. For this problem, the probability of obtaining a clearly undersampled k{sub eff} decreased from 5% with a uniform starting source to zero with a deterministic starting source when batch sizes with more than 15,000 neutron/cycle were used.

Ibrahim, A. [University of Wisconsin; Peplow, Douglas E. [ORNL; Wagner, John C [ORNL; Mosher, Scott W [ORNL; Evans, Thomas M [ORNL

2012-01-01T23:59:59.000Z

355

Probing the 3.6 Micron CIRB with Spitzer in 3 DIRBE Dark Spots  

E-Print Network (OSTI)

We observed three regions of the sky with Spitzer in which the Cosmic InfraRed Background (CIRB) has been determined at 3.5 microns using the method of subtracting 2MASS stellar fluxes from zodiacal light subtracted DIRBE maps. For each of these regions we have obtained 270 seconds of integration time per pixel with IRAC on Spitzer over the central square degree. We present galaxy counts in each of these approximately 1 square degree IRAC surveys. Along with deep galaxy counts in the Extended Groth Strip and GOODS North, we are able to compare the galactic contribution to the CIRB with the "DIRBE minus 2MASS'' determined L-band CIRB. Using the profile-fit photometry package GIM2D, we find a substantially larger flux contribution to the CIRB than that determined using aperture photometry. We have also made the first rigorous analysis of the uncertainties in determining the CIRB via galaxy counts in Spitzer images using a Monte Carlo Markov Chain simulation of our data analysis. Using a simple broken power law model for galaxy counts as a function of magnitude we find a most probable contribution to the CIRB from galaxies at 3.6 microns of 10.8^{+2.1}_{-1.1} kJy/sr. Even with this restricted model, however, we find that galaxy counting does not strongly constrain the CIRB from above. We are able to find solutions in which the CIRB runs away to large intensities without the need for an additional diffuse source.

L. R. Levenson; E. L. Wright

2008-02-11T23:59:59.000Z

356

Magnetostatic focal spot correction for x-ray tubes operating in strong magnetic fields using iterative optimization  

Science Conference Proceedings (OSTI)

Purpose: Combining x-ray fluoroscopy and MR imaging systems for guidance of interventional procedures has become more commonplace. By designing an x-ray tube that is immune to the magnetic fields outside of the MR bore, the two systems can be placed in close proximity to each other. A major obstacle to robust x-ray tube design is correcting for the effects of the magnetic fields on the x-ray tube focal spot. A potential solution is to design active shielding that locally cancels the magnetic fields near the focal spot. Methods: An iterative optimization algorithm is implemented to design resistive active shielding coils that will be placed outside the x-ray tube insert. The optimization procedure attempts to minimize the power consumption of the shielding coils while satisfying magnetic field homogeneity constraints. The algorithm is composed of a linear programming step and a nonlinear programming step that are interleaved with each other. The coil results are verified using a finite element space charge simulation of the electron beam inside the x-ray tube. To alleviate heating concerns an optimized coil solution is derived that includes a neodymium permanent magnet. Any demagnetization of the permanent magnet is calculated prior to solving for the optimized coils. The temperature dynamics of the coil solutions are calculated using a lumped parameter model, which is used to estimate operation times of the coils before temperature failure. Results: For a magnetic field strength of 88 mT, the algorithm solves for coils that consume 588 A/cm{sup 2}. This specific coil geometry can operate for 15 min continuously before reaching temperature failure. By including a neodymium magnet in the design the current density drops to 337 A/cm{sup 2}, which increases the operation time to 59 min. Space charge simulations verify that the coil designs are effective, but for oblique x-ray tube geometries there is still distortion of the focal spot shape along with deflections of approximately 3 mm in the radial and circumferential directions on the anode. Conclusions: Active shielding is an attractive solution for correcting the effects of magnetic fields on the x-ray focal spot. If extremely long fluoroscopic exposure times are required, longer operation times can be achieved by including a permanent magnet with the active shielding design.

Lillaney, Prasheel; Shin, Mihye; Conolly, Steven M.; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Bioengineering, University of California Berkeley, Berkeley, California 94720 (United States) and Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California 94720 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States)

2012-09-15T23:59:59.000Z

357

Oxygen chemisorption on Cu(19 19 1) studied by spot profile analysis low-energy electron diffraction  

SciTech Connect

Cu(110) and the vicinal Cu(19 19 1) surfaces were characterized by recording maps of the reciprocal space by means of spot profile analysis low-energy electron diffraction (SPA-LEED). For both surfaces, kinematic simulations were performed to get insight into the main features of the experimental data. Furthermore, it is shown that chemisorption of oxygen and subsequent annealing lead to the formation of a Cu-CuO stripe phase and induce faceting of the Cu(19 19 1) surface. The evolution from the clean Cu(19 19 1) surface to the coexistence of the (110) and (111) facets with increasing oxygen exposure was characterized by SPA-LEED.

Brandstetter, T.; Draxler, M.; Hohage, M.; Zeppenfeld, P. [Institut fuer Experimentalphysik, Johannes Kepler Universitaet Linz, A-4040 Linz (Austria)

2007-12-15T23:59:59.000Z

358

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

SciTech Connect

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

359

In the OSTI Collections: Monte Carlo Methods | OSTI, US Dept of Energy,  

Office of Scientific and Technical Information (OSTI)

Monte Carlo Methods Monte Carlo Methods "The first thoughts and attempts I made ... were suggested by a question which occurred to me in 1946 as I was convalescing from an illness and playing solitaires. The question was what are the chances that a Canfield solitaire laid out with 52 cards will come out successfully? After spending a lot of time trying to estimate them by pure combinatorial calculations, I wondered whether a more practical method than 'abstract thinking' might not be to lay it out say one hundred times and simply observe and count the number of successful plays. This was already possible to envisage with the beginning of the new era of fast computers, and I immediately thought of problems of neutron diffusion and other questions of mathematical physics,

360

The energy injection and losses in the Monte Carlo simulations of a diffusive shock  

E-Print Network (OSTI)

Although diffusive shock acceleration (DSA) could be simulated by some well-established models, the assumption of the injection rate from the thermal particles to the superthermal population is still a contentious problem. But in the self-consistent Monte Carlo simulations, because of the prescribed scattering law instead of the assumption of the injected function, hence particle injection rate is intrinsically defined by the prescribed scattering law. We expect to examine the correlation of the energy injection with the prescribed multiple scattering angular distributions. According to the Rankine-Hugoniot conditions, the energy injection and the losses in the simulation system can directly decide the shock energy spectrum slope. By the simulations performed with multiple scattering law in the dynamical Monte Carlo model, the energy injection and energy loss functions are obtained. As results, the case applying anisotropic scattering law produce a small energy injection and large energy losses leading to a s...

Wang, Xin

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.


361

Adaptive kinetic Monte Carlo simulation of methanol decomposition on Cu(100)  

DOE Green Energy (OSTI)

The adaptive kinetic Monte Carlo method was used to calculate the dynamics of methanol decomposition on Cu(100) at room temperature over a time scale of minutes. Mechanisms of reaction were found using min-mode following saddle point searches based upon forces and energies from density functional theory. Rates of reaction were calculated with harmonic transition state theory. The dynamics followed a pathway from CH3-OH, CH3-O, CH2-O, CH-O and finally C-O. Our calculations confirm that methanol decomposition starts with breaking the O-H bond followed by breaking C-H bonds in the dehydrogenated intermediates until CO is produced. The bridge site on the Cu(100) surface is the active site for scissoring chemical bonds. Reaction intermediates are mobile on the surface which allows them to find this active reaction site. This study illustrates how the adaptive kinetic Monte Carlo method can model the dynamics of surface chemistry from first principles.

Xu, Lijun; Mei, Donghai; Henkelman, Graeme A.

2009-12-31T23:59:59.000Z

362

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

363

Under-Prediction of Localized Tally Uncertainties in Monte Carlo Eigenvalue Calculations  

SciTech Connect

Modeling and simulation using Monte Carlo methods is widely used in nuclear reactor criticality benchmarking applications. However, obtaining good statistics not only takes a large amount of computational time, but it has been shown that localized tally uncertainties may be under-predicted by a factor of five or more in select cases. The primary components of this under-prediction include poor sampling due to improper source convergence and cycle-to-cycle correlations in the fission source. Additional components relate to the flux shape and the size of the tally cells. These issues must be understood and dealt with in order to support the practical use of modern Monte Carlo software packages.

Mervin, Mervin Brenden [University of Tennessee, Knoxville (UTK); Mosher, Scott W [ORNL; Wagner, John C [ORNL; Maldonado, G. Ivan [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

364

Empirical Analysis of Stochastic Volatility Model by Hybrid Monte Carlo Algorithm  

E-Print Network (OSTI)

The stochastic volatility model is one of volatility models which infer latent volatility of asset returns. The Bayesian inference of the stochastic volatility (SV) model is performed by the hybrid Monte Carlo (HMC) algorithm which is superior to other Markov Chain Monte Carlo methods in sampling volatility variables. We perform the HMC simulations of the SV model for two liquid stock returns traded on the Tokyo Stock Exchange and measure the volatilities of those stock returns. Then we calculate the accuracy of the volatility measurement using the realized volatility as a proxy of the true volatility and compare the SV model with the GARCH model which is one of other volatility models. Using the accuracy calculated with the realized volatility we find that empirically the SV model performs better than the GARCH model.

Takaishi, Tetsuya

2013-01-01T23:59:59.000Z

365

Barges haul LP-gas on inland waterways and the deep-blue sea  

SciTech Connect

Warren Petroleum Co. (Tulsa) owns 23 LP-gas barges and leases another eight to 10, depending on need, for transporting product from Mont Belvieu to terminals on the inland waterways and east to Florida and down into the Caribbean. One of these barges is the Sioux, recently completed by Fredeman Shipyard, located at Carlyss, La. Upon delivery to the owner, M and W Barge Co. of Belle Chasse, La., the barge went on charter to Warren Petroleum. Built under the supervision of project manager Terry T. Frickey, the barge took nine months to complete and provided 20 new jobs at the shipyard. The company is currently negotiating for a similar barge-construction contract.

Not Available

1988-03-01T23:59:59.000Z

366

Comments on the use of the Monte Carlo method for criticality calculations  

SciTech Connect

As evidenced by recent papers given at Nuclear Criticality Safety Division meetings, the use of the Monte Carlo method has become a very popular computational tool. The ease of use has undoubtably been a primary reason for this popularity. This ease of use, however, may lead to a false sense of security when using the method. Guidance on the effective use of the method and some suggestions on how to avoid some of the pitfalls that can occur are presented. (TFD)

Whitesides, G.E.

1975-01-01T23:59:59.000Z

367

Radiative equilibrium in Monte Carlo radiative transfer using frequency distribution adjustment  

E-Print Network (OSTI)

The Monte Carlo method is a powerful tool for performing radiative equilibrium calculations, even in complex geometries. The main drawback of the standard Monte Carlo radiative equilibrium methods is that they require iteration, which makes them numerically very demanding. Bjorkman & Wood recently proposed a frequency distribution adjustment scheme, which allows radiative equilibrium Monte Carlo calculations to be performed without iteration, by choosing the frequency of each re-emitted photon such that it corrects for the incorrect spectrum of the previously re-emitted photons. Although the method appears to yield correct results, we argue that its theoretical basis is not completely transparent, and that it is not completely clear whether this technique is an exact rigorous method, or whether it is just a good and convenient approximation. We critically study the general problem of how an already sampled distribution can be adjusted to a new distribution by adding data points sampled from an adjustment distribution. We show that this adjustment is not always possible, and that it depends on the shape of the original and desired distributions, as well as on the relative number of data points that can be added. Applying this theorem to radiative equilibrium Monte Carlo calculations, we provide a firm theoretical basis for the frequency distribution adjustment method of Bjorkman & Wood, and we demonstrate that this method provides the correct frequency distribution through the additional requirement of radiative equilibrium. We discuss the advantages and limitations of this approach, and show that it can easily be combined with the presence of additional heating sources and the concept of photon weighting. However, the method may fail if small dust grains are included... (abridged)

Maarten Baes; Dimitris Stamatellos; Jonathan I. Davies; Anthony P. Whitworth; Sabina Sabatini; Sarah Roberts; Suzanne M. Linder; Rhodri Evans

2005-04-01T23:59:59.000Z

368

Validation of a Monte Carlo Based Depletion Methodology Using HFIR Post-Irradiation Measurements  

Science Conference Proceedings (OSTI)

Post-irradiation uranium isotopic atomic densities within the core of the High Flux Isotope Reactor (HFIR) were calculated and compared to uranium mass spectrographic data measured in the late 1960s and early 70s [1]. This study was performed in order to validate a Monte Carlo based depletion methodology for calculating the burn-up dependent nuclide inventory, specifically the post-irradiation uranium

Chandler, David [ORNL; Maldonado, G Ivan [ORNL; Primm, Trent [ORNL

2009-11-01T23:59:59.000Z

369

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

SciTech Connect

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

370

A comparison of the Monte Carlo and the flux gradient method for atmospheric diffusion  

DOE Green Energy (OSTI)

In order to model the dispersal of atmospheric pollutants in the planetary boundary layer, various methods of parameterizing turbulent diffusion have been employed. The purpose of this paper is to use a three-dimensional particle-in-cell transport and diffusion model to compare the Markov chain (Monte Carlo) method of statistical particle diffusion with the deterministic flux gradient (K-theory) method. The two methods are heavily used in the study of atmospheric diffusion under complex conditions, with the Monte Carlo method gaining in popularity partly because of its more direct application of turbulence parameters. The basis of comparison is a data set from night-time drainage flow tracer experiments performed by the US Department of Energy Atmospheric Studies in Complex Terrain (ASCOT) program at the Geysers geothermal region in northern California. The Atmospheric Diffusion Particle-In-Cell (ADPIC) model used is the main model in the Lawrence Livermore National Laboratory emergency response program: Atmospheric Release Advisory Capability (ARAC). As a particle model, it can simulate diffusion in both the flux gradient and Monte Carlo modes. 9 refs., 6 figs.

Lange, R.

1990-05-01T23:59:59.000Z

371

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

SciTech Connect

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

372

A comparison of generalized hybrid Monte Carlo methods with and without momentum flip  

Science Conference Proceedings (OSTI)

The generalized hybrid Monte Carlo (GHMC) method combines Metropolis corrected constant energy simulations with a partial random refreshment step in the particle momenta. The standard detailed balance condition requires that momenta are negated upon rejection of a molecular dynamics proposal step. The implication is a trajectory reversal upon rejection, which is undesirable when interpreting GHMC as thermostated molecular dynamics. We show that a modified detailed balance condition can be used to implement GHMC without momentum flips. The same modification can be applied to the generalized shadow hybrid Monte Carlo (GSHMC) method. Numerical results indicate that GHMC/GSHMC implementations with momentum flip display a favorable behavior in terms of sampling efficiency, i.e., the traditional GHMC/GSHMC implementations with momentum flip got the advantage of a higher acceptance rate and faster decorrelation of Monte Carlo samples. The difference is more pronounced for GHMC. We also numerically investigate the behavior of the GHMC method as a Langevin-type thermostat. We find that the GHMC method without momentum flip interferes less with the underlying stochastic molecular dynamics in terms of autocorrelation functions and it to be preferred over the GHMC method with momentum flip. The same finding applies to GSHMC.

Akhmatskaya, Elena [Fujitsu Laboratories of Europe Ltd (FLE), Hayes Park Central, Hayes End Road, Hayes UB4 8FE (United Kingdom); Bou-Rabee, Nawaf [Department of Mathematics, Freie Universitaet Berlin, Arnimallee 2-6, 14195 Berlin (Germany); Reich, Sebastian [Universitaet Potsdam, Institut fuer Mathematik, Am Neuen Palais 10, D-14469 Potsdam (Germany)], E-mail: s.reich@ic.ac.uk

2009-04-01T23:59:59.000Z

373

Spatial homogenization of thermal feedback regions in Monte Carlo reactor calculations  

SciTech Connect

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

374

Combining Total Monte Carlo and Benchmarks for nuclear data uncertainty propagation on an LFRs safety parameters  

E-Print Network (OSTI)

Analyses are carried out to assess the impact of nuclear data uncertainties on keff for the European Lead Cooled Training Reactor (ELECTRA) using the Total Monte Carlo method. A large number of Pu-239 random ENDF-formated libraries generated using the TALYS based system were processed into ACE format with NJOY99.336 code and used as input into the Serpent Monte Carlo neutron transport code to obtain distribution in keff. The keff distribution obtained was compared with the latest major nuclear data libraries - JEFF-3.1.2, ENDF/B-VII.1 and JENDL-4.0. A method is proposed for the selection of benchmarks for specific applications using the Total Monte Carlo approach. Finally, an accept/reject criterion was investigated based on chi square values obtained using the Pu-239 Jezebel criticality benchmark. It was observed that nuclear data uncertainties in keff were reduced considerably from 748 to 443 pcm by applying a more rigid acceptance criteria for accepting random files.

Alhassan, Erwin; Duan, Junfeng; Gustavsson, Cecilia; Koning, Arjan; Pomp, Stephan; Rochman, Dimitri; Österlund, Michael

2013-01-01T23:59:59.000Z

375

A second-quantized red herring in full configuration-interaction Monte Carlo  

E-Print Network (OSTI)

Full configuration-interaction quantum Monte Carlo (FCI-QMC) is a Monte Carlo method that allows for exact solution of the ground state of fermionic Hamiltonians (albeit at exponential cost). FCI-QMC involves stochastic projection to the ground state, working in a basis of second- quantized determinants. While a Fermi sign problem still exists within FCI-QMC, it has been suggested that even without annihilation the sign problem is fundamentally distinct from that of more standard techniques such as diffusion Monte Carlo, as a result of working in determinant space. Furthermore, it is widely believed that this distinction is at least partially responsible for the success of FCI-QMC in mitigating the sign problem. In this paper, we show that second quantization is a red herring; the sign problem of FCI-QMC comes from the conventional instability to a bosonic ground state, and in fact FCI-QMC without annihilation can be equated step-by-step to a first-quantized algorithm where anti-symmetry comes only from initi...

Kolodrubetz, Michael

2012-01-01T23:59:59.000Z

376

Quantum Monte-Carlo method applied to Non-Markovian barrier transmission  

E-Print Network (OSTI)

In nuclear fusion and fission, fluctuation and dissipation arise due to the coupling of collective degrees of freedom with internal excitations. Close to the barrier, both quantum, statistical and non-Markovian effects are expected to be important. In this work, a new approach based on quantum Monte-Carlo addressing this problem is presented. The exact dynamics of a system coupled to an environment is replaced by a set of stochastic evolutions of the system density. The quantum Monte-Carlo method is applied to systems with quadratic potentials. In all range of temperature and coupling, the stochastic method matches the exact evolution showing that non-Markovian effects can be simulated accurately. A comparison with other theories like Nakajima-Zwanzig or Time-ConvolutionLess ones shows that only the latter can be competitive if the expansion in terms of coupling constant is made at least to fourth order. A systematic study of the inverted parabola case is made at different temperatures and coupling constants. The asymptotic passing probability is estimated in different approaches including the Markovian limit. Large differences with the exact result are seen in the latter case or when only second order in the coupling strength is considered as it is generally assumed in nuclear transport models. On opposite, if fourth order in the coupling or quantum Monte-Carlo method is used, a perfect agreement is obtained.

G. Hupin; D. Lacroix

2010-01-05T23:59:59.000Z

377

MC21 analysis of the nuclear energy agency Monte Carlo performance benchmark problem  

SciTech Connect

Due to the steadily decreasing cost and wider availability of large scale computing platforms, there is growing interest in the prospects for the use of Monte Carlo for reactor design calculations that are currently performed using few-group diffusion theory or other low-order methods. To facilitate the monitoring of the progress being made toward the goal of practical full-core reactor design calculations using Monte Carlo, a performance benchmark has been developed and made available through the Nuclear Energy Agency. A first analysis of this benchmark using the MC21 Monte Carlo code was reported on in 2010, and several practical difficulties were highlighted. In this paper, a newer version of MC21 that addresses some of these difficulties has been applied to the benchmark. In particular, the confidence-interval-determination method has been improved to eliminate source correlation bias, and a fission-source-weighting method has been implemented to provide a more uniform distribution of statistical uncertainties. In addition, the Forward-Weighted, Consistent-Adjoint-Driven Importance Sampling methodology has been applied to the benchmark problem. Results of several analyses using these methods are presented, as well as results from a very large calculation with statistical uncertainties that approach what is needed for design applications. (authors)

Kelly, D. J.; Sutton, T. M. [Knolls Atomic Power Laboratory, Bechtel Marine Propulsion Corporation, P. O. Box 1072, Schenectady, NY 12301-1072 (United States); Wilson, S. C. [Bertis Atomic Power Laboratory, Bechtel Marine Propulsion Corporation, P. O. Box 79, West Mifflin, PA 15122-0079 (United States)

2012-07-01T23:59:59.000Z

378

Combining Total Monte Carlo and Benchmarks for nuclear data uncertainty propagation on an LFRs safety parameters  

E-Print Network (OSTI)

Analyses are carried out to assess the impact of nuclear data uncertainties on keff for the European Lead Cooled Training Reactor (ELECTRA) using the Total Monte Carlo method. A large number of Pu-239 random ENDF-formated libraries generated using the TALYS based system were processed into ACE format with NJOY99.336 code and used as input into the Serpent Monte Carlo neutron transport code to obtain distribution in keff. The keff distribution obtained was compared with the latest major nuclear data libraries - JEFF-3.1.2, ENDF/B-VII.1 and JENDL-4.0. A method is proposed for the selection of benchmarks for specific applications using the Total Monte Carlo approach. Finally, an accept/reject criterion was investigated based on chi square values obtained using the Pu-239 Jezebel criticality benchmark. It was observed that nuclear data uncertainties in keff were reduced considerably from 748 to 443 pcm by applying a more rigid acceptance criteria for accepting random files.

Erwin Alhassan; Henrik Sjöstrand; Junfeng Duan; Cecilia Gustavsson; Arjan Koning; Stephan Pomp; Dimitri Rochman; Michael Österlund

2013-03-26T23:59:59.000Z

379

Monte Carlo Simulation of Daily Regional Sulfur Distribution: Comparison with SURE Sulfate Data and Visual Range Observations during August 1977  

Science Conference Proceedings (OSTI)

The daily distribution of sulfate concentration over the eastern United States during August 1977 is simulated by a Monte Carlo model using quantized emissions, positioned in accordance with the 1973 EPA SO2 emission inventory. Horizontal ...

D. E. Patterson; R. B. Husar; W. E. Wilson; L. F. Smith

1981-04-01T23:59:59.000Z

380

Bayesian Inference and Markov Chain Monte Carlo Sampling to Reconstruct a Contaminant Source on a Continental Scale  

Science Conference Proceedings (OSTI)

A methodology combining Bayesian inference with Markov chain Monte Carlo (MCMC) sampling is applied to a real accidental radioactive release that occurred on a continental scale at the end of May 1998 near Algeciras, Spain. The source parameters (...

Luca Delle Monache; Julie K. Lundquist; Branko Kosovi?; Gardar Johannesson; Kathleen M. Dyer; Roger D. Aines; Fotini K. Chow; Rich D. Belles; William G. Hanley; Shawn C. Larsen; Gwen A. Loosmore; John J. Nitao; Gayle A. Sugiyama; Philip J. Vogt

2008-10-01T23:59:59.000Z

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.


381

Dispersion of Particles Released into a Neutral Planetary Boundary Layer Using a Markov Chain–Monte Carlo Model  

Science Conference Proceedings (OSTI)

The dispersion and concentration of particles (fluid elements) that are continuously released into a neutral planetary boundary layer is presented. The velocity fluctuations of the particles are generated using a Markov chain–Monte Carlo (MCMC) ...

R. Avila; S. S. Raza

2005-07-01T23:59:59.000Z

382

Computational Cost and Accuracy in Calculating Three-Dimensional Radiative Transfer: Results for New Implementations of Monte Carlo and SHDOM  

Science Conference Proceedings (OSTI)

This paper examines the tradeoffs between computational cost and accuracy for two new state-of-the-art codes for computing three-dimensional radiative transfer: a community Monte Carlo model and a parallel implementation of the Spherical ...

Robert Pincus; K. Franklin Evans

2009-10-01T23:59:59.000Z

383

TOPAS: An innovative proton Monte Carlo platform for research and clinical applications  

Science Conference Proceedings (OSTI)

Purpose: While Monte Carlo particle transport has proven useful in many areas (treatment head design, dose calculation, shielding design, and imaging studies) and has been particularly important for proton therapy (due to the conformal dose distributions and a finite beam range in the patient), the available general purpose Monte Carlo codes in proton therapy have been overly complex for most clinical medical physicists. The learning process has large costs not only in time but also in reliability. To address this issue, we developed an innovative proton Monte Carlo platform and tested the tool in a variety of proton therapy applications. Methods: Our approach was to take one of the already-established general purpose Monte Carlo codes and wrap and extend it to create a specialized user-friendly tool for proton therapy. The resulting tool, TOol for PArticle Simulation (TOPAS), should make Monte Carlo simulation more readily available for research and clinical physicists. TOPAS can model a passive scattering or scanning beam treatment head, model a patient geometry based on computed tomography (CT) images, score dose, fluence, etc., save and restart a phase space, provides advanced graphics, and is fully four-dimensional (4D) to handle variations in beam delivery and patient geometry during treatment. A custom-designed TOPAS parameter control system was placed at the heart of the code to meet requirements for ease of use, reliability, and repeatability without sacrificing flexibility. Results: We built and tested the TOPAS code. We have shown that the TOPAS parameter system provides easy yet flexible control over all key simulation areas such as geometry setup, particle source setup, scoring setup, etc. Through design consistency, we have insured that user experience gained in configuring one component, scorer or filter applies equally well to configuring any other component, scorer or filter. We have incorporated key lessons from safety management, proactively removing possible sources of user error such as line-ordering mistakes. We have modeled proton therapy treatment examples including the UCSF eye treatment head, the MGH stereotactic alignment in radiosurgery treatment head and the MGH gantry treatment heads in passive scattering and scanning modes, and we have demonstrated dose calculation based on patient-specific CT data. Initial validation results show agreement with measured data and demonstrate the capabilities of TOPAS in simulating beam delivery in 3D and 4D. Conclusions: We have demonstrated TOPAS accuracy and usability in a variety of proton therapy setups. As we are preparing to make this tool freely available for researchers in medical physics, we anticipate widespread use of this tool in the growing proton therapy community.

Perl, J.; Shin, J.; Schuemann, J.; Faddegon, B.; Paganetti, H. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); University of California San Francisco Comprehensive Cancer Center, 1600 Divisadero Street, San Francisco, California 94143-1708 (United States); Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); University of California San Francisco Comprehensive Cancer Center, 1600 Divisadero Street, San Francisco, California 94143-1708 (United States); Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)

2012-11-15T23:59:59.000Z

384

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

Science Conference Proceedings (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

385

RBU: A COMBINED MONTE CARLO REACTOR-BURNUP PROGRAM FOR THE IBM 709  

SciTech Connect

RBU is a digital computer program for the detailed calculation of the neutron, reactivity, and isotopic history of a reactor in which relatively exact models of the geometry and physical processes are included to permit reliable pre dictions of fuel costs and reactor performance. The program uses the Monte Carlo method to obtain the fine structure of the neutron flux in three space dimensions and energy. Using this fine structure, cross sections are averaged over space and energy to obtain the neutronic properties for equivalent homogeneous one- dimensional regions of space and ranges of energy. These are used in diffusion calculations to obtain the macroscopic flux distribution throughout the reactor. The consumption and production of isotopes is computed for a time step by the solution of sets of partial differential equations involving both the macroscopic and microscopic fluxes. With the new concentrations, diffusion calculations are performed again to obtain macroscopic fluxes for the next time step. At variable intervals, Monte Carlo calculations are again performed to determine the changes in microscopic flux distributions. The cycle is repeated until conditions on the reactivity or other properties dictate the end of the calculation. Programmed control rod manipulation may be included in the calculation. The Monte Carlo, diffusion, or burnup portions of the program may be used separately. The unresolved resonance range is treated by random selection of resonance parameters from appropriate distributions using the Doppler broadened single level Breit- Wigner formula. Resolved resonances are treated similarly with the exception that specific values of the resonance parameters are used. The effects of molecular binding and thermal motion of the nuclei on near-thermal scattering are treated by a simple model capable of incorporating the pertinent physical theory and data. (auth)

Leshan, E.J.; Burr, J.R.; Temme, M.; Thompson, G.T.; Triplett, J.R.

1959-09-30T23:59:59.000Z

386

A User's Manual for MASH V1.5 - A Monte Carlo Adjoint Shielding Code System  

Science Conference Proceedings (OSTI)

The Monte Carlo ~djoint ~ielding Code System, MASH, calculates neutron and gamma- ray environments and radiation protection factors for armored military vehicles, structures, trenches, and other shielding configurations by coupling a forward discrete ordinates air- over-ground transport calculation with an adjoint Monte Carlo treatment of the shielding geometry. Efficiency and optimum use of computer time are emphasized. The code system includes the GRTUNCL and DORT codes for air-over-ground transport calculations, the MORSE code with the GIFT5 combinatorial geometry package for adjoint shielding calculations, and several peripheral codes that perform the required data preparations, transformations, and coupling functions. The current version, MASH v 1.5, is the successor to the original MASH v 1.0 code system initially developed at Oak Ridge National Laboratory (ORNL). The discrete ordinates calculation determines the fluence on a coupling surface surrounding the shielding geometry due to an external neutron/gamma-ray source. The Monte Carlo calculation determines the effectiveness of the fluence at that surface in causing a response in a detector within the shielding geometry, i.e., the "dose importance" of the coupling surface fluence. A coupling code folds the fluence together with the dose importance, giving the desired dose response. The coupling code can determine the dose response as a function of the shielding geometry orientation relative to the source, distance from the source, and energy response of the detector. This user's manual includes a short description of each code, the input required to execute the code along with some helpful input data notes, and a representative sample problem.

C. O. Slater; J. M. Barnes; J. O. Johnson; J.D. Drischler

1998-10-01T23:59:59.000Z

387

Using a Reduced Spot Size for Intensity-Modulated Proton Therapy Potentially Improves Salivary Gland-Sparing in Oropharyngeal Cancer  

Science Conference Proceedings (OSTI)

Purpose: To investigate whether intensity-modulated proton therapy with a reduced spot size (rsIMPT) could further reduce the parotid and submandibular gland dose compared with previously calculated IMPT plans with a larger spot size. In addition, it was investigated whether the obtained dose reductions would theoretically translate into a reduction of normal tissue complication probabilities (NTCPs). Methods: Ten patients with N0 oropharyngeal cancer were included in a comparative treatment planning study. Both IMPT plans delivered simultaneously 70 Gy to the boost planning target volume (PTV) and 54 Gy to the elective nodal PTV. IMPT and rsIMPT used identical three-field beam arrangements. In the IMPT plans, the parotid and submandibular salivary glands were spared as much as possible. rsIMPT plans used identical dose-volume objectives for the parotid glands as those used by the IMPT plans, whereas the objectives for the submandibular glands were tightened further. NTCPs were calculated for salivary dysfunction and xerostomia. Results: Target coverage was similar for both IMPT techniques, whereas rsIMPT clearly improved target conformity. The mean doses in the parotid glands and submandibular glands were significantly lower for three-field rsIMPT (14.7 Gy and 46.9 Gy, respectively) than for three-field IMPT (16.8 Gy and 54.6 Gy, respectively). Hence, rsIMPT significantly reduced the NTCP of patient-rated xerostomia and parotid and contralateral submandibular salivary flow dysfunction (27%, 17%, and 43% respectively) compared with IMPT (39%, 20%, and 79%, respectively). In addition, mean dose values in the sublingual glands, the soft palate and oral cavity were also decreased. Obtained dose and NTCP reductions varied per patient. Conclusions: rsIMPT improved sparing of the salivary glands and reduced NTCP for xerostomia and parotid and submandibular salivary dysfunction, while maintaining similar target coverage results. It is expected that rsIMPT improves quality of life during and after radiotherapy treatment.

Water, Tara A. van de, E-mail: t.a.van.de.water@rt.umcg.nl [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Lomax, Antony J. [Centre for Proton Therapy, Paul Scherrer Institute, Villigen-PSI (Switzerland); Bijl, Hendrik P.; Schilstra, Cornelis [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Hug, Eugen B. [Centre for Proton Therapy, Paul Scherrer Institute, Villigen-PSI (Switzerland); Langendijk, Johannes A. [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)

2012-02-01T23:59:59.000Z

388

A simulation study to verify Stone's simultaneous water and gas injection performance in a 5-spot pattern  

E-Print Network (OSTI)

Water alternating gas (WAG) injection is a proven technique to enhance oil recovery. It has been successfully implemented in the field since 1957 with recovery increase in the range of 5-10% of oil-initially-in-place (OIIP). In 2004, Herbert L. Stone presented a simultaneous water and gas injection technique. Gas is injected near the bottom of the reservoir and water is injected directly on top at high rates to prevent upward channeling of the gas. Stone's mathematical model indicated the new technique can increase vertical sweep efficiency by 3-4 folds over WAG. In this study, a commercial reservoir simulator was used to predict the performance of Stone's technique and compare it to WAG and other EOR injection strategies. Two sets of relative permeability data were considered. Multiple combinations of total injection rates (water plus gas) and water/gas ratios as well as injection schedules were investigated to find the optimum design parameters for an 80 acre 5-spot pattern unit. Results show that injecting water above gas may result in better oil recovery than WAG injection though not as indicated by Stone. Increase in oil recovery with SSWAG injection is a function of the gas critical saturation. The more gas is trapped in the formation, the higher oil recovery is obtained. This is probably due to the fact that areal sweep efficiency is a more dominant factor in a 5-spot pattern. Periodic shut-off of the water injector has little effect on oil recovery. Water/gas injection ratio optimization may result in a slight increase in oil recovery. SSWAG injection results in a steady injection pressure and less fluctuation in gas production rate compared to WAG injection.

Barnawi, Mazen Taher

2008-05-01T23:59:59.000Z

389

Sequential Monte Carlo simulation for composite power system reliability analysis with time varying loads  

SciTech Connect

The paper illustrates the development and utilization of an annual chronological load curve for each load bus in a composite generation and transmission system and a sequential Monte Carlo simulation approach for composite system reliability assessment. Antithetic variates as a variance reduction technique has been applied to the simulation model to increase the efficiency of the simulation. An approximate method using a load duration curve of the system load and an enumeration process have been applied to the developed load model and the results are compared in this paper.

Sankarakrishnan, A.; Billinton, R. [Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada). Power Systems Research Group

1995-08-01T23:59:59.000Z

390

Quest for precision in hadronic cross sections at low energy: Monte Carlo tools vs. experimental data  

E-Print Network (OSTI)

We present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low energy e+e- colliders in Beijing, Frascati, Ithaca, Novosibirsk, Stanford and Tsukuba and on tau decays. We sketch the prospects in these fields for the years to come. We emphasise the status and the precision of the Monte Carlo generators used to analyse the hadronic cross section measurements obtained as well with energy scans as with radiative return, to determine luminosities and tau decays. The radiative corrections fully or approximately implemented in the various codes and the contribution of the vacuum polarisation are discussed.

Actis, S; Arbuzov, A; Balossini, G; Beltrame, P; Bignamini, C; Bonciani, R; Carloni Calame, C M; Cherepanov, V; Czakon, M; Czyz, H; Denig, A; Eidelman, S; Fedotovich, G V; Ferroglia, A; Gluza, J; Grzeli nska, A; Gunia, M; Hafner, A; Ignatov, F; Jadach, S; Jegerlehner, F; Kalinowski, A; Kluge, W; Korchin, A; Kuhn, J H; Kuraev, E A; Lukin, P; Mastrolia, P; Montagna, G; Muller, S E; Nguyen, F; Nicrosini, O; Nomura, D; Pakhlova, G; Pancheri, G; Passera, M; Penin, A; Piccinini, F; Placzek, W; Przedzinski, T; Remiddi, E; Riemann, T; Rodrigo, G; Roig, P; Shekhovtsova, O; Shen, C P; Sibidanov, A L; Teubner, T; Trentadue, L; Venanzoni, G; van der Bij, J J; Wang, P; Ward, B F L; Was, Z; Worek, M; Yuan, C Z

2010-01-01T23:59:59.000Z

391

First Results From GLAST-LAT Integrated Towers Cosmic Ray Data Taking And Monte Carlo Comparison  

SciTech Connect

GLAST Large Area Telescope (LAT) is a gamma ray telescope instrumented with silicon-strip detector planes and sheets of converter, followed by a calorimeter (CAL) and surrounded by an anticoincidence system (ACD). This instrument is sensitive to gamma rays in the energy range between 20 MeV and 300 GeV. At present, the first towers have been integrated and pre-launch data taking with cosmic ray muons is being performed. The results from the data analysis carried out during LAT integration will be discussed and a comparison with the predictions from the Monte Carlo simulation will be shown.

Brigida, M.; Caliandro, A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giordano, F.; Giglietto, N.; Loparco, F.; Marangelli, B.; Mazziotta, M.N.; Mirizzi, N.; Raino, S.; Spinelli, P.; /Bari U. /INFN, Bari

2007-02-15T23:59:59.000Z

392

A Hybrid (Monte-Carlo/Deterministic) Approach for Multi-Dimensional Radiation Transport  

E-Print Network (OSTI)

A novel hybrid Monte Carlo transport scheme is demonstrated in a scene with solar illumination, scattering and absorbing 2D atmosphere, a textured reflecting mountain, and a small detector located in the sky (mounted on a satellite or a airplane). It uses a deterministic approximation of an adjoint transport solution to reduce variance, computed quickly by ignoring atmospheric interactions. This allows significant variance and computational cost reductions when the atmospheric scattering and absorption coefficient are small. When combined with an atmospheric photon-redirection scheme, significant variance reduction (equivalently acceleration) is achieved in the presence of atmospheric interactions.

Guillaume Bal; Anthony Davis; Ian Langmore

2011-05-07T23:59:59.000Z

393

Extrapolation method in the Monte Carlo Shell Model and its applications  

SciTech Connect

We demonstrate how the energy-variance extrapolation method works using the sequence of the approximated wave functions obtained by the Monte Carlo Shell Model (MCSM), taking {sup 56}Ni with pf-shell as an example. The extrapolation method is shown to work well even in the case that the MCSM shows slow convergence, such as {sup 72}Ge with f5pg9-shell. The structure of {sup 72}Se is also studied including the discussion of the shape-coexistence phenomenon.

Shimizu, Noritaka; Abe, Takashi [Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Utsuno, Yutaka [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Mizusaki, Takahiro [Institute of Natural Sciences, Senshu University, Tokyo, 101-8425 (Japan); Otsuka, Takaharu [Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Center for Nuclear Study, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan (United States); Honma, Michio [Center for Mathematical Sciences, Aizu University, Aizu-Wakamatsu, Fukushima 965-8580 (Japan)

2011-05-06T23:59:59.000Z

394

Characterisation of radiation damage in silicon photomultipliers with a Monte Carlo model  

E-Print Network (OSTI)

Measured response functions and low photon yield spectra of silicon photomultipliers (SiPM) were compared to multi-photoelectron pulse-height distributions generated by a Monte Carlo model. Characteristic parameters for SiPM were derived. The devices were irradiated with 14 MeV electrons at the Mainz microtron MAMI. It is shown that the first noticeable damage consists of an increase in the rate of dark pulses and the loss of uniformity in the pixel gains. Higher radiation doses reduced also the photon detection efficiency. The results are especially relevant for applications of SiPM in fibre detectors at high luminosity experiments.

S. Sanchez Majos; P. Achenbach; J. Pochodzalla

2008-05-27T23:59:59.000Z

395

ETRANMS: a one-dimensional Monte Carlo electron/photon transport code for multimaterial targets  

SciTech Connect

ETRANMS is an LLL-modified version of the one-dimensional electron/ photon transport code ETRAN 15 developed at the National bureau of Standards. The major modifications include the use of LLL photon cross sections and the application to multislab, multimaterial targets. The code uses Monte Carlo sampling techniques to calculate electron and photon transport and energy and charge deposition within target material subjected to electron or photon radiation. It has been programmed to be a very rapid running, user-oriented code for use on LLL's CDC 7600 computers. (auth)

Kovar, F.R.

1973-11-30T23:59:59.000Z

396

A 3D Monte Carlo Photoionization Code for Modeling Diffuse Ionized Gas  

E-Print Network (OSTI)

We have developed a three dimensional Monte Carlo photoionization code tailored for the study of Galactic H II regions and the percolation of ionizing photons in diffuse ionized gas. We describe the code, our calculation of photoionization, heating & cooling, and the approximations we have employed for the low density H II regions we wish to study. Our code gives results in agreement with the Lexington H II region benchmarks. We show an example of a 2D shadowed region and point out the very significant effect that diffuse radiation produced by recombinations of helium has on the temperature within the shadow.

Wood, K; Ercolano, B

2004-01-01T23:59:59.000Z

397

Monte Carlo simulation of ferroelectric domain structure: Electrostatic and elastic strain energy contributions  

DOE Green Energy (OSTI)

A lattice-Monte Carlo approach was developed to simulate ferroelectric domain behavior. The model utilizes a Hamiltonian for the total energy that includes electrostatic terms (involving dipole-dipole interactions, local polarization gradients, and applied electric field), and elastic strain energy. The contributions of these energy components to the domain structure and to the overall applied field response of the system were examined. In general, the model exhibited domain structure characteristics consistent with those observed in a tetragonally distorted ferroelectric. Good qualitative agreement between the appearance of simulated electrical hysteresis loops and those characteristic of real ferroelectric materials was found.

POTTER JR.,BARRETT G.; TUTTLE,BRUCE A.; TIKARE,VEENA

2000-04-04T23:59:59.000Z

398

SIM-RIBRAS: A Monte-Carlo simulation package for RIBRAS system  

Science Conference Proceedings (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

399

Use of SCALE Continuous-Energy Monte Carlo Tools for Eigenvalue Sensitivity Coefficient Calculations  

Science Conference Proceedings (OSTI)

The TSUNAMI code within the SCALE code system makes use of eigenvalue sensitivity coefficients for an extensive number of criticality safety applications, such as quantifying the data-induced uncertainty in the eigenvalue of critical systems, assessing the neutronic similarity between different critical systems, and guiding nuclear data adjustment studies. The need to model geometrically complex systems with improved fidelity and the desire to extend TSUNAMI analysis to advanced applications has motivated the development of a methodology for calculating sensitivity coefficients in continuous-energy (CE) Monte Carlo applications. The CLUTCH and Iterated Fission Probability (IFP) eigenvalue sensitivity methods were recently implemented in the CE KENO framework to generate the capability for TSUNAMI-3D to perform eigenvalue sensitivity calculations in continuous-energy applications. This work explores the improvements in accuracy that can be gained in eigenvalue and eigenvalue sensitivity calculations through the use of the SCALE CE KENO and CE TSUNAMI continuous-energy Monte Carlo tools as compared to multigroup tools. The CE KENO and CE TSUNAMI tools were used to analyze two difficult models of critical benchmarks, and produced eigenvalue and eigenvalue sensitivity coefficient results that showed a marked improvement in accuracy. The CLUTCH sensitivity method in particular excelled in terms of efficiency and computational memory requirements.

Perfetti, Christopher M [ORNL; Rearden, Bradley T [ORNL

2013-01-01T23:59:59.000Z

400

Quantum Monte Carlo algorithms for electronic structure at the petascale; the endstation project.  

SciTech Connect

Over the past two decades, continuum quantum Monte Carlo (QMC) has proved to be an invaluable tool for predicting of the properties of matter from fundamental principles. By solving the Schrodinger equation through a stochastic projection, it achieves the greatest accuracy and reliability of methods available for physical systems containing more than a few quantum particles. QMC enjoys scaling favorable to quantum chemical methods, with a computational effort which grows with the second or third power of system size. This accuracy and scalability has enabled scientific discovery across a broad spectrum of disciplines. The current methods perform very efficiently at the terascale. The quantum Monte Carlo Endstation project is a collaborative effort among researchers in the field to develop a new generation of algorithms, and their efficient implementations, which will take advantage of the upcoming petaflop architectures. Some aspects of these developments are discussed here. These tools will expand the accuracy, efficiency and range of QMC applicability and enable us to tackle challenges which are currently out of reach. The methods will be applied to several important problems including electronic and structural properties of water, transition metal oxides, nanosystems and ultracold atoms.

Kim, J; Ceperley, D M; Purwanto, W; Walter, E J; Krakauer, H; Zhang, S W; Kent, P.R. C; Hennig, R G; Umrigar, C; Bajdich, M; Kolorenc, J; Mitas, L

2008-10-01T23:59:59.000Z

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.


401

Massively parallel Monte Carlo for many-particle simulations on GPUs  

E-Print Network (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.

Joshua A. Anderson; Eric Jankowski; Thomas L. Grubb; Michael Engel; Sharon C. Glotzer

2012-11-07T23:59:59.000Z

402

Exploiting symmetries for exponential error reduction in path integral Monte Carlo  

E-Print Network (OSTI)

The path integral of a quantum system with an exact symmetry can be written as a sum of functional integrals each giving the contribution from quantum states with definite symmetry properties. We propose a strategy to compute each of them, normalized to the one with vacuum quantum numbers, by a Monte Carlo procedure whose cost increases power-like with the time extent of the lattice. This is achieved thanks to a multi-level integration scheme, inspired by the transfer matrix formalism, which exploits the symmetry and the locality in time of the underlying statistical system. As a result the cost of computing the lowest energy level in a given channel, its multiplicity and its matrix elements is exponentially reduced with respect to the standard path-integral Monte Carlo. We test the strategy with a one-dimensional harmonic oscillator, by computing the ratio of the parity odd over the parity even functional integrals and the two-point correlation function. The cost of the simulations scales as expected. In par...

Della Morte, Michele

2009-01-01T23:59:59.000Z

403

Electron energy losses near pulsar polar caps: a Monte Carlo approach  

E-Print Network (OSTI)

We use Monte Carlo approach to study the energetics of electrons accelerated in a pulsar polar gap. As energy-loss mechanisms we consider magnetic Compton scattering of thermal X-ray photons and curvature radiation. The results are compared with previous calculations which assumed that changes of electron energy occurred smoothly according to approximations for the average energy loss rate due to the Compton scattering. We confirm a general dependence of efficiency of electron energy losses due to inverse Compton mechanism on the temperature and size of a thermal polar cap and on the pulsar magnetic field. However, we show that trajectories of electrons in energy-altitude space as calculated in the smooth way do not always coincide with averaged Monte Carlo behaviour. In particular, for pulsars with high magnetic field strength ($B_{pc} > 3\\times 10^{12}$ G) and low thermal polar cap temperatures ($T < 5\\times 10^6$ K) final electron Lorentz factors computed with the two methods may differ by a few orders of magnitude. We discuss consequences for particular objects with identified thermal X-ray spectral components like Geminga, Vela, and PSR B1055-52.

J. Dyks; B. Rudak

2000-03-07T23:59:59.000Z

404

Basic physical and chemical information needed for development of Monte Carlo codes  

SciTech Connect

It is important to view track structure analysis as an application of a branch of theoretical physics (i.e., statistical physics and physical kinetics in the language of the Landau school). Monte Carlo methods and transport equation methods represent two major approaches. In either approach, it is of paramount importance to use as input the cross section data that best represent the elementary microscopic processes. Transport analysis based on unrealistic input data must be viewed with caution, because results can be misleading. Work toward establishing the cross section data, which demands a wide scope of knowledge and expertise, is being carried out through extensive international collaborations. In track structure analysis for radiation biology, the need for cross sections for the interactions of electrons with DNA and neighboring protein molecules seems to be especially urgent. Finally, it is important to interpret results of Monte Carlo calculations fully and adequately. To this end, workers should document input data as thoroughly as possible and report their results in detail in many ways. Workers in analytic transport theory are then likely to contribute to the interpretation of the results.

Inokuti, M.

1993-08-01T23:59:59.000Z

405

Physics and Algorithm Enhancements for a Validated MCNP/X Monte Carlo Simulation Tool, Phase VII  

SciTech Connect

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

406

Surface Structures of Cubo-octahedral Pt-Mo Catalyst Nanoparticles from Monte Carlo Simulations  

DOE Green Energy (OSTI)

The surface structures of cubo-octahedral Pt-Mo nanoparticles have been investigated using the Monte Carlo method and modified embedded atom method potentials that we developed for Pt-Mo alloys. The cubo-octahedral Pt-Mo nanoparticles are constructed with disordered fcc configurations, with sizes from 2.5 to 5.0 nm, and with Pt concentrations from 60 to 90 at. percent. The equilibrium Pt-Mo nanoparticle configurations were generated through Monte Carlo simulations allowing both atomic displacements and element exchanges at 600 K. We predict that the Pt atoms weakly segregate to the surfaces of such nanoparticles. The Pt concentrations in the surface are calculated to be 5 to 14 at. percent higher than the Pt concentrations of the nanoparticles. Moreover, the Pt atoms preferentially segregate to the facet sites of the surface, while the Pt and Mo atoms tend to alternate along the edges and vertices of these nanoparticles. We found that decreasing the size or increasing the Pt concentration leads to higher Pt concentrations but fewer Pt-Mo pairs in the Pt-Mo nanoparticle surfaces.

Wang, Guofeng; Van Hove, M.A.; Ross, P.N.; Baskes, M.I.

2005-03-31T23:59:59.000Z

407

An Evaluation of Monte Carlo Simulations of Neutron Multiplicity Measurements of Plutonium Metal  

Science Conference Proceedings (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

408

Speciation model selection by Monte Carlo analysis of optical absorption spectra: Plutonium(IV) nitrate complexes  

Science Conference Proceedings (OSTI)

Standard modeling approaches can produce the most likely values of the formation constants of metal-ligand complexes if a particular set of species containing the metal ion is known or assumed to exist in solution equilibrium with complexing ligands. Identifying the most likely set of species when more than one set is plausible is a more difficult problem to address quantitatively. A Monte Carlo method of data analysis is described that measures the relative abilities of different speciation models to fit optical spectra of open-shell actinide ions. The best model(s) can be identified from among a larger group of models initially judged to be plausible. The method is demonstrated by analyzing the absorption spectra of aqueous Pu(IV) titrated with nitrate ion at constant 2 molal ionic strength in aqueous perchloric acid. The best speciation model supported by the data is shown to include three Pu(IV) species with nitrate coordination numbers 0, 1, and 2. Formation constants are {beta}{sub 1}=3.2{+-}0.5 and {beta}{sub 2}=11.2{+-}1.2, where the uncertainties are 95% confidence limits estimated by propagating raw data uncertainties using Monte Carlo methods. Principal component analysis independently indicates three Pu(IV) complexes in equilibrium. (c) 2000 Society for Applied Spectroscopy.

Berg, John M. [Nuclear Materials Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Veirs, D. Kirk [Nuclear Materials Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Vaughn, Randolph B. [Nuclear Materials Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Cisneros, Michael R. [Nuclear Materials Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Smith, Coleman A. [Nuclear Materials Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2000-06-01T23:59:59.000Z

409

Configuration-interaction Monte Carlo method and its application to the trapped unitary Fermi gas  

E-Print Network (OSTI)

We develop a quantum Monte Carlo method to estimate the ground-state energy of a fermionic many-particle system in the configuration-interaction shell model approach. The fermionic sign problem is circumvented by using a guiding wave function in Fock space. The method provides an upper bound on the ground-state energy whose tightness depends on the choice of the guiding wave function. We argue that the antisymmetric geminal product class of wave functions is a good choice for guiding wave functions. We demonstrate our method for the trapped two-species fermionic cold atom system in the unitary regime of infinite scattering length using the particle-number projected Hartree-Fock-Bogoliubov wave function as the guiding wave function. We estimate the ground-state energy and energy-staggering pairing gap as a function of the number of particles. Our results compare favorably with exact numerical diagonalization results and with previous coordinate-space Monte Carlo calculations.

Mukherjee, Abhishek

2013-01-01T23:59:59.000Z

410

Configuration-interaction Monte Carlo method and its application to the trapped unitary Fermi gas  

E-Print Network (OSTI)

We develop a quantum Monte Carlo method to estimate the ground-state energy of a fermionic many-particle system in the configuration-interaction shell model approach. The fermionic sign problem is circumvented by using a guiding wave function in Fock space. The method provides an upper bound on the ground-state energy whose tightness depends on the choice of the guiding wave function. We argue that the antisymmetric geminal product class of wave functions is a good choice for guiding wave functions. We demonstrate our method for the trapped two-species fermionic cold atom system in the unitary regime of infinite scattering length using the particle-number projected Hartree-Fock-Bogoliubov wave function as the guiding wave function. We estimate the ground-state energy and energy-staggering pairing gap as a function of the number of particles. Our results compare favorably with exact numerical diagonalization results and with previous coordinate-space Monte Carlo calculations.

Abhishek Mukherjee; Y. Alhassid

2013-04-05T23:59:59.000Z

411

Automatic Mesh Adaptivity for Hybrid Monte Carlo/Deterministic Neutronics Modeling of Fusion Energy Systems  

SciTech Connect

Three mesh adaptivity algorithms were developed to facilitate and expedite the use of the CADIS and FW-CADIS hybrid Monte Carlo/deterministic techniques in accurate full-scale neutronics simulations of fusion energy systems with immense sizes and complicated geometries. First, a macromaterial approach enhances the fidelity of the deterministic models without changing the mesh. Second, a deterministic mesh refinement algorithm generates meshes that capture as much geometric detail as possible without exceeding a specified maximum number of mesh elements. Finally, a weight window coarsening algorithm decouples the weight window mesh and energy bins from the mesh and energy group structure of the deterministic calculations in order to remove the memory constraint of the weight window map from the deterministic mesh resolution. The three algorithms were used to enhance an FW-CADIS calculation of the prompt dose rate throughout the ITER experimental facility and resulted in a 23.3% increase in the number of mesh tally elements in which the dose rates were calculated in a 10-day Monte Carlo calculation. Additionally, because of the significant increase in the efficiency of FW-CADIS simulations, the three algorithms enabled this difficult calculation to be accurately solved on a regular computer cluster, eliminating the need for a world-class super computer.

Ibrahim, Ahmad M [ORNL; Wilson, P. [University of Wisconsin; Sawan, M. [University of Wisconsin; Mosher, Scott W [ORNL; Peplow, Douglas E. [ORNL; Grove, Robert E [ORNL

2013-01-01T23:59:59.000Z

412

A Deterministic-Monte Carlo Hybrid Method for Time-Dependent Neutron Transport Problems  

Science Conference Proceedings (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

413

GUINEVERE experiment: Kinetic analysis of some reactivity measurement methods by deterministic and Monte Carlo codes  

Science Conference Proceedings (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

414

RunMC - an object-oriented analysis framework for Monte Carlo simulation of high-energy particle collisions  

E-Print Network (OSTI)

RunMC is an object-oriented framework aimed to generate and to analyse high-energy collisions of elementary particles using Monte Carlo simulations. This package, being based on C++ adopted by CERN as the main programming language for the LHC experiments, provides a common interface to different Monte Carlo models using modern physics libraries. Physics calculations (projects) can easily be loaded and saved as external modules. This simplifies the development of complicated calculations for high energy physics in large collaborations.This desktop program is open-source licensed and is available on the LINUX and Windows/Cygwin platforms.

S. Chekanov

2004-11-05T23:59:59.000Z

415

Overview of Geometry Representation in Monte Carlo Codes Ronald P. Kensek  

National Nuclear Security Administration (NNSA)

Overview of Geometry Representation Overview of Geometry Representation in Monte Carlo Codes Ronald P. Kensek Brian C. Franke Thomas W. Laub Leonard J. Lorence Matthew R. Martin Sandia National Laboratories Steve Warren Kansas State University Joint Russian-American Five-Laboratory Conference on Computational Mathematics / Physics Vienna, Austria June 19-23, 2005 Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States National Nuclear Security Administration and the Department of Energy under contract DE-AC04-94AL85000. 2 Problem Setup: Engineering designs CG vs. CAD Combinatorial Geometry (CG) * Engineering designs are not typically created in this format * No general automatic translation from CAD to CG yet exists * Problem setup is difficult: Creation

416

State and parameter estimation using Monte Carlo evaluation of path integrals  

E-Print Network (OSTI)

Transferring information from observations of a dynamical system to estimate the fixed parameters and unobserved states of a system model can be formulated as the evaluation of a discrete time path integral in model state space. The observations serve as a guiding potential working with the dynamical rules of the model to direct system orbits in state space. The path integral representation permits direct numerical evaluation of the conditional mean path through the state space as well as conditional moments about this mean. Using a Monte Carlo method for selecting paths through state space we show how these moments can be evaluated and demonstrate in an interesting model system the explicit influence of the role of transfer of information from the observations. We address the question of how many observations are required to estimate the unobserved state variables, and we examine the assumptions of Gaussianity of the underlying conditional probability.

John C. Quinn; Henry D. I. Abarbanel

2009-12-08T23:59:59.000Z

417

Validation of the Monte Carlo Criticality Program KENO V. a for highly-enriched uranium systems  

SciTech Connect

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

418

Suppressing nonphysical overheating with a modified implicit Monte Carlo method for time-dependent radiative transfer  

SciTech Connect

In this note we develop a robust implicit Monte Carlo (IMC) algorithm based on more accurately updating the linearized equilibrium radiation energy density. The method does not introduce oscillations in the solution and has the same limit as {Delta}t{yields}{infinity} as the standard Fleck and Cummings IMC method. Moreover, the approach we introduce can be trivially added to current implementations of IMC by changing the definition of the Fleck factor. Using this new method we develop an adaptive scheme that uses either standard IMC or the modified method basing the adaptation on a zero-dimensional problem solved in each cell. Numerical results demonstrate that the new method alleviates both the nonphysical overheating that occurs in standard IMC when the time step is large and significantly diminishes the statistical noise in the solution.

Mcclarren, Ryan G [Los Alamos National Laboratory; Urbatsch, Todd J [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

419

Cation dopant distributions in nanostructures of transition-metal doped ZnO:Monte Carlo simulations  

SciTech Connect

The path from trace doping to solid solution formation involves an intermediate regime in which the doping level is a few to several atomic percent. In this regime, dopant-dopant interactions, which are driven by the spatial arrangement of dopants, are critical factors in determining the resulting properties. Conventional wisdom counts on simple probabilistic methods for predicting dopant distributions. Here, we use Monte Carlo simulations to show that widely used, straightforward statistical models, such as that of Behringer1, are accurate only in the limit of infinitesimally small surface–to-volume ratio. For epitaxial films and nanoparticles, where much of the current interest resides, dopant distributions depend strongly on the surface-to-volume ratio. We present empirical expressions that accurately predict dopant bonding configurations as a function of film or particle size, shape and dopant concentration for doped ZnO, a material of particular interest in semiconductor spintronics.

Droubay, Timothy; Kaspar, Tiffany C.; Kaspar, Bryce P.; Chambers, Scott A.

2009-02-01T23:59:59.000Z

420

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

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.


421

MC++: A parallel, portable, Monte Carlo neutron transport code in C++  

SciTech Connect

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

422

A Monte-Carlo method for ex-core neutron response  

SciTech Connect

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

423

Frozen-orbital and downfolding calculations with auxiliary-field quantum Monte Carlo  

E-Print Network (OSTI)

We describe the implementation of the frozen-orbital and downfolding approximations in the auxiliary-field quantum Monte Carlo (AFQMC) method. These approaches can provide significant computational savings compared to fully correlating all the electrons. While the many-body wave function is never explicit in AFQMC, its random walkers are Slater determinants, whose orbitals may be expressed in terms of any one-particle orbital basis. It is therefore straightforward to partition the full N-particle Hilbert space into active and inactive parts to implement the frozen-orbital method. In the frozen-core approximation, for example, the core electrons can be eliminated in the correlated part of the calculations, greatly increasing the computational efficiency, especially for heavy atoms. Scalar relativistic effects are easily included using the Douglas-Kroll-Hess theory. Using this method, we obtain a way to effectively eliminate the error due to single-projector, norm-conserving pseudopotentials in AFQMC. We also i...

Purwanto, Wirawan; Krakauer, Henry

2013-01-01T23:59:59.000Z

424

Monte Carlo calculation of the transition temperature of the anisotropic three-dimensional {ital XY} model  

SciTech Connect

The transition temperature of the spatially anisotropic three-dimensional classical {ital XY} model is calculated by means of Monte Carlo (MC) simulations. In the {ital XY} model the spins are not restricted to the {ital XY} plane, as in the plane rotator model. The results are compared with a self-consistent harmonic approximation calculation (SCHA). In two dimensions the inclusion of effect of vortices pushes down the transition temperature from {ital T}{sub KT}/{ital J}=1.08, given by the standard SCHA to {ital T}{sub KT}/{ital J}=0.70, in good agreement with the MC estimate {ital T}{sub KT}/{ital J}=0.725. {copyright} {ital 1996 The American Physical Society.}

Costa, B.V.; Pereira, A.R.; Pires, A.S. [Departamento de Fisica, Universidade Federal de Minas Gerais, CP 702, Belo Horizonte, 30161970 Minas Gerais (Brazil)] [Departamento de Fisica, Universidade Federal de Minas Gerais, CP 702, Belo Horizonte, 30161970 Minas Gerais (Brazil)

1996-08-01T23:59:59.000Z

425

Local Monte Carlo Implementation of the Non-Abelian Landau-Pomeranchuk-Migdal Effect  

SciTech Connect

The non-Abelian Landau-Pomeranschuk-Migdal (LPM) effect arises from the quantum interference between spatially separated, inelastic radiation processes in matter. A consistent probabilistic implementation of this LPM effect is a prerequisite for extending the use of Monte Carlo (MC) event generators to the simulation of jetlike multiparticle final states in nuclear collisions. Here, we propose a local MC algorithm, which is based solely on relating the LPM effect to the probabilistic concept of formation time for virtual quanta. This accounts probabilistically for the characteristic L{sup 2} dependence of average parton energy loss and the characteristic 1/sq root(omega) modification of the non-Abelian LPM effect. Additional kinematic constraints are found to modify these L{sup 2} and omega dependencies characteristically in accordance with analytical estimates.

Zapp, Korinna [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); EMMI, GSI Helmholtz-Institut fuer Ionenforschung, Planckstrasse 1, D-64291 Darmstadt (Germany); Stachel, Johanna [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Wiedemann, Urs Achim [Physics Department, Theory Unit, CERN, CH-1211 Geneve 23 (Switzerland)

2009-10-09T23:59:59.000Z

426

Improving computational efficiency of Monte-Carlo simulations with variance reduction  

E-Print Network (OSTI)

CCFE perform Monte-Carlo transport simulations on large and complex tokamak models such as ITER. Such simulations are challenging since streaming and deep penetration effects are equally important. In order to make such simulations tractable, both variance reduction (VR) techniques and parallel computing are used. It has been found that the application of VR techniques in such models significantly reduces the efficiency of parallel computation due to 'long histories'. VR in MCNP can be accomplished using energy-dependent weight windows. The weight window represents an 'average behaviour' of particles, and large deviations in the arriving weight of a particle give rise to extreme amounts of splitting being performed and a long history. When running on parallel clusters, a long history can have a detrimental effect on the parallel efficiency - if one process is computing the long history, the other CPUs complete their batch of histories and wait idle. Furthermore some long histories have been found to be effect...

Turner, A

2013-01-01T23:59:59.000Z

427

Dynamic Monte Carlo simulation of coupled transport through a narrow multiply-occupied pore  

E-Print Network (OSTI)

Dynamic Monte Carlo simulations are used to study coupled transport (co-transport) through sub-nanometer-diameter pores. In this classic Hodgkin-Keynes mechanism, an ion species uses the large flux of an abundant ion species to move against its concentration gradient. The efficiency of co-transport is examined for various pore parameters so that synthetic nanopores can be engineered to maximize this effect. In general, the pore must be narrow enough that ions cannot pass each other and the charge of the pore large enough to attract many ions so that they exchange momentum. Co-transport efficiency increases as pore length increases, but even very short pores exhibit co-transport, in contradiction to the usual perception that long pores are necessary. The parameter ranges where co-transport occurs is consistent with current and near-future synthetic nanopore geometry parameters, suggesting that co-transport of ions may be a new application of nanopores.

Dezs? Boda; Éva Csányi; Dirk Gillespie; Tamás Kristóf

2013-10-08T23:59:59.000Z

428

Coupled coarse graining and Markov Chain Monte Carlo for lattice systems  

E-Print Network (OSTI)

We propose an efficient Markov Chain Monte Carlo method for sampling equilibrium distributions for stochastic lattice models, capable of handling correctly long and short-range particle interactions. The proposed method is a Metropolis-type algorithm with the proposal probability transition matrix based on the coarse-grained approximating measures introduced in a series of works of M. Katsoulakis, A. Majda, D. Vlachos and P. Plechac, L. Rey-Bellet and D.Tsagkarogiannis,. We prove that the proposed algorithm reduces the computational cost due to energy differences and has comparable mixing properties with the classical microscopic Metropolis algorithm, controlled by the level of coarsening and reconstruction procedure. The properties and effectiveness of the algorithm are demonstrated with an exactly solvable example of a one dimensional Ising-type model, comparing efficiency of the single spin-flip Metropolis dynamics and the proposed coupled Metropolis algorithm.

Kalligiannaki, Evangelia; Plechac, Petr

2010-01-01T23:59:59.000Z

429

Study of CANDU thorium-based fuel cycles by deterministic and Monte Carlo methods  

Science Conference Proceedings (OSTI)

In the framework of the Generation IV forum, there is a renewal of interest in self-sustainable thorium fuel cycles applied to various concepts such as Molten Salt Reactors [1, 2] or High Temperature Reactors [3, 4]. Precise evaluations of the U-233 production potential relying on existing reactors such as PWRs [5] or CANDUs [6] are hence necessary. As a consequence of its design (online refueling and D{sub 2}O moderator in a thermal spectrum), the CANDU reactor has moreover an excellent neutron economy and consequently a high fissile conversion ratio [7]. For these reasons, we try here, with a shorter term view, to re-evaluate the economic competitiveness of once-through thorium-based fuel cycles in CANDU [8]. Two simulation tools are used: the deterministic Canadian cell code DRAGON [9] and MURE [10], a C++ tool for reactor evolution calculations based on the Monte Carlo code MCNP [11]. (authors)

Nuttin, A.; Guillemin, P. [LPSC Grenoble ENSPG (France); Courau, T. [EDF R and D Clamart (France); Marleau, G. [Ecole Polytechnique de Montreal (Canada); Meplan, O. [LPSC Grenoble UJF (France); David, S.; Michel-Sendis, F.; Wilson, J. N. [IPN Orsay CNRS (France)

2006-07-01T23:59:59.000Z

430

Converting Boundary Representation Solid Models to Half-Space Representation Models for Monte Carlo Analysis  

SciTech Connect

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

431

Monte Carlo simulation of ion trajectories in the modified PDX thermal charge exchange analyzer  

DOE Green Energy (OSTI)

An improved design for the present PDX thermal charge exchange analyzer (MACE) has been proposed by one of the authors, in which the five cylindrical electrostatic plates for mass separation are replaced by a single flat, electrostatic deflection plate. An existihg Monte Carlo code that simulated the passage of ions through the MACE analyzer was modified to examine the feasibility of this change. The resulting calculations were used to optimize detector positions and collimation requirements. The first analyzer to be placed on PDX will be of the old design, similar to the present PLT analyzer. However, if the design reported here is successful on the test stand, the future PDX analyzers will all be of the new, single electrostatic plate variety. A further advantage will be the ability to install as many as ten detectors instead of the current five, thus providing twice as many energy channels for each shot. Also, both mass species (H, D) can be measured concurrently, if desired.

Kaita, R.; Davis, S.L.; Medley, S.S.

1978-12-01T23:59:59.000Z

432

Investigation of a V{sub 15} magnetic molecular nanocluster by the Monte Carlo method  

SciTech Connect

Exchange interactions in a V{sub 15} magnetic molecular nanocluster are considered, and the process of magnetization reversal for various values of the set of exchange constants is analyzed by the Monte Carlo method. It is shown that the best agreement between the field dependence of susceptibility and experimental results is observed for the following set of exchange interaction constants in a V{sub 15} magnetic molecular nanocluster: J = 500 K, J Prime = 150 K, J Double-Prime = 225 K, J{sub 1} = 50 K, and J{sub 2} = 50 K. It is observed for the first time that, in a strong magnetic field, for each of the three transitions from low-spin to high-spin states, the heat capacity exhibits two closely spaced maxima.

Khizriev, K. Sh., E-mail: kamal71@mail.ru [Russian Academy of Sciences, Kh.I. Amirkhanov Institute of Physics, Dagestan Scientific Center (Russian Federation); Dzhamalutdinova, I. S.; Taaev, T. A. [Dagestan State University (Russian Federation)

2013-06-15T23:59:59.000Z

433

Bayesian Inference for LISA Pathfinder using Markov Chain Monte Carlo Methods  

E-Print Network (OSTI)

We present a parameter estimation procedure based on a Bayesian framework by applying a Markov Chain Monte Carlo algorithm to the calibration of the dynamical parameters of a space based gravitational wave detector. The method is based on the Metropolis-Hastings algorithm and a two-stage annealing treatment in order to ensure an effective exploration of the parameter space at the beginning of the chain. We compare two versions of the algorithm with an application to a LISA Pathfinder data analysis problem. The two algorithms share the same heating strategy but with one moving in coordinate directions using proposals from a multivariate Gaussian distribution, while the other uses the natural logarithm of some parameters and proposes jumps in the eigen-space of the Fisher Information matrix. The algorithm proposing jumps in the eigen-space of the Fisher Information matrix demonstrates a higher acceptance rate and a slightly better convergence towards the equilibrium parameter distributions in the application to...

Ferraioli, Luigi; Plagnol, Eric

2012-01-01T23:59:59.000Z

434

A Markov-Chain Monte-Carlo Based Method for Flaw Detection in Beams  

SciTech Connect

A Bayesian inference methodology using a Markov Chain Monte Carlo (MCMC) sampling procedure is presented for estimating the parameters of computational structural models. This methodology combines prior information, measured data, and forward models to produce a posterior distribution for the system parameters of structural models that is most consistent with all available data. The MCMC procedure is based upon a Metropolis-Hastings algorithm that is shown to function effectively with noisy data, incomplete data sets, and mismatched computational nodes/measurement points. A series of numerical test cases based upon a cantilever beam is presented. The results demonstrate that the algorithm is able to estimate model parameters utilizing experimental data for the nodal displacements resulting from specified forces.

Glaser, R E; Lee, C L; Nitao, J J; Hickling, T L; Hanley, W G

2006-09-28T23:59:59.000Z

435

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

436

Hybrid Monte-Carlo simulation of interacting tight-binding model of graphene  

E-Print Network (OSTI)

In this work, results are presented of Hybrid-Monte-Carlo simulations of the tight-binding Hamiltonian of graphene, coupled to an instantaneous long-range two-body potential which is modeled by a Hubbard-Stratonovich auxiliary field. We present an investigation of the spontaneous breaking of the sublattice symmetry, which corresponds to a phase transition from a conducting to an insulating phase and which occurs when the effective fine-structure constant $\\alpha$ of the system crosses above a certain threshold $\\alpha_C$. Qualitative comparisons to earlier works on the subject (which used larger system sizes and higher statistics) are made and it is established that $\\alpha_C$ is of a plausible magnitude in our simulations. Also, we discuss differences between simulations using compact and non-compact variants of the Hubbard field and present a quantitative comparison of distinct discretization schemes of the Euclidean time-like dimension in the Fermion operator.

Dominik Smith; Lorenz von Smekal

2013-11-05T23:59:59.000Z

437

Monte Carlo based dosimetry and treatment planning for neutron capture therapy of brain tumors  

Science Conference Proceedings (OSTI)

Monte Carlo based dosimetry and computer-aided treatment planning for neutron capture therapy have been developed to provide the necessary link between physical dosimetric measurements performed on the MITR-II epithermal-neutron beams and the need of the radiation oncologist to synthesize large amounts of dosimetric data into a clinically meaningful treatment plan for each individual patient. Monte Carlo simulation has been employed to characterize the spatial dose distributions within a skull/brain model irradiated by an epithermal-neutron beam designed for neutron capture therapy applications. The geometry and elemental composition employed for the mathematical skull/brain model and the neutron and photon fluence-to-dose conversion formalism are presented. A treatment planning program, NCTPLAN, developed specifically for neutron capture therapy, is described. Examples are presented illustrating both one and two-dimensional dose distributions obtainable within the brain with an experimental epithermal-neutron beam, together with beam quality and treatment plan efficacy criteria which have been formulated for neutron capture therapy. The incorporation of three-dimensional computed tomographic image data into the treatment planning procedure is illustrated. The experimental epithermal-neutron beam has a maximum usable circular diameter of 20 cm, and with 30 ppm of B-10 in tumor and 3 ppm of B-10 in blood, it produces a beam-axis advantage depth of 7.4 cm, a beam-axis advantage ratio of 1.83, a global advantage ratio of 1.70, and an advantage depth RBE-dose rate to tumor of 20.6 RBE-cGy/min (cJ/kg-min). These characteristics make this beam well suited for clinical applications, enabling an RBE-dose of 2,000 RBE-cGy/min (cJ/kg-min) to be delivered to tumor at brain midline in six fractions with a treatment time of approximately 16 minutes per fraction.

Zamenhof, R.G.; Clement, S.D.; Harling, O.K.; Brenner, J.F.; Wazer, D.E.; Madoc-Jones, H.; Yanch, J.C. (Tufts-New England Medical Center, Boston, MA (USA))

1990-01-01T23:59:59.000Z

438

Monte Carlo Electromagnetic Cross Section Production Method for Low Energy Charged Particle Transport Through Single Molecules  

E-Print Network (OSTI)

The present state of modeling radio-induced effects at the cellular level neglects to account for the microscopic inhomogeneity of the nucleus from the non-aqueous contents by approximating the entire cellular nucleus as a homogenous medium of water. Charged particle track-structure calculations utilizing this principle of superposition are thereby neglecting to account for approximately 30% of the molecular variation within the nucleus. To truly understand what happens when biological matter is irradiated, charged particle track-structure calculations need detailed knowledge of the secondary electron cascade, resulting from interactions with not only the primary biological component – water – but also the non-aqueous contents, down to very low energies. This paper presents developments for a novel approach, which to our knowledge has never been done before, to reducing the homogenous water approximation. The purpose of our work is to develop of a completely self-consistent computational method for predicting molecule-specific ionization, excitation, and scattering cross sections in the very low energy regime that can be applied in a condensed history Monte Carlo track-structure code. The present methodology begins with the calculation of a solution to the many-body Schrödinger equation and proceeds to use Monte Carlo methods to calculate the perturbations in the internal electron field to determine the aforementioned processes. Results are computed for molecular water in the form of linear energy loss, secondary electron energies, and ionization-to-excitation ratios and compared against the low energy predictions of the GEANT4-DNA physics package of the Geant4 simulation toolkit.

Madsen, Jonathan R

2013-08-01T23:59:59.000Z

439

Using Markov Chain Monte Carlo to quantify parameter uncertainty and its effect on predictions of a groundwater flow model  

Science Conference Proceedings (OSTI)

A statistical Bayesian framework is used to solve the inverse problem and develop the posterior distributions of parameters for a density-driven groundwater flow model. This Bayesian approach is implemented using a Markov Chain Monte Carlo (MCMC) sampling ... Keywords: Conditioning, Groundwater model calibration, Inverse problems, MCMC, Numerical modelling

Ahmed E. Hassan; Hesham M. Bekhit; Jenny B. Chapman

2009-06-01T23:59:59.000Z

440

Abstract--The paper focuses on reliability assessment of power systems with wind power generation. A Monte Carlo based  

E-Print Network (OSTI)

. A Monte Carlo based production cost simulation model is introduced in the paper. The model closely for wind power can be established. Over the years, analytical methods [2]-[4] had been extensively utilized based production cost simulation model had been investigated and developed. The model simulates

McCalley, James D.

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

Graphs of the cross sections in the recommended Monte Carlo cross-section library at the Los Alamos Scientific Laboratory  

Science Conference Proceedings (OSTI)

Graphs of all neutron cross sections and photon production cross sections on the Recommended Monte Carlo Cross Section (RMCCS) library have been plotted along with local neutron heating numbers. Values for anti ..nu.., the average number of neutrons per fission, are also given.

Soran, P.D.; Seamon, R.E.

1980-05-01T23:59:59.000Z

442

The sizes and powers of some stochastic dominance tests: A Monte Carlo study for correlated and heteroskedastic distributions  

Science Conference Proceedings (OSTI)

Testing for stochastic dominance among distributions is an important issue in the study of asset management, income inequality, and market efficiency. This paper conducts Monte Carlo simulations to examine the sizes and powers of several commonly used ... Keywords: C12, Correlated distributions, D31, G11, Grid points, Heteroskedasticity, Stochastic dominance

Hooi-Hooi Lean; Wing-Keung Wong; Xibin Zhang

2008-10-01T23:59:59.000Z

443

Study of Horizontally Oriented Ice Crystals with CALIPSO Observations and Comparison with Monte Carlo Radiative Transfer Simulations  

E-Print Network (OSTI)

Study of Horizontally Oriented Ice Crystals with CALIPSO Observations and Comparison with Monte oriented ice crystals (HOIC) occur frequently in both ice and mixed-phase clouds. When compared with the case for clouds consisting of randomly oriented ice crystals (ROIC), lidar measurements from clouds

Baum, Bryan A.

444

The estimation techniques of the time series correlations in nuclear reactor calculations by the Monte Carlo method using multiprocessor computers  

Science Conference Proceedings (OSTI)

The algorithms of estimation of the time series correlation functions in nuclear reactor calculations using the Monte Carlo method are described. Correlation functions are used for the estimation of biases, for calculations of variance taking into account the correlations between neutron generations, and for choosing skipped generations.

Kalugin, M. A.; Oleynik, D. S.; Sukhino-Khomenko, E. A., E-mail: sukhino-khomenko@adis.vver.kiae.ru [National Research Centre Kurchatov Institute (Russian Federation)

2012-12-15T23:59:59.000Z

445

Analytical Solution of a Simplified Transport Problem with Continuous Energy for Testing Monte Carlo Procedures,” this conference  

E-Print Network (OSTI)

A simplified transport problem is presented with continuous energy and neutrons moving only into the +X and –X direction. An exact analytical solution is given with a 1/E energy dependence of the space, direction and energy dependent neutron flux. The source function, which also behaves basically as 1/E has to be modified for a certain energy range if a maximum energy is introduced in the problem. At the cost of more complicated mathematics the total and scattering cross sections and the anisotropy of scattering may very with energy. This model can be implemented in a general purpose Monte Carlo code like MCNP5 without modification, but needs a specially prepared cross section library file. The model can be applied to test Monte Carlo procedures, like the generation of multi-group cross section and scattering matrices which can be calculated analytically from the continuous-energy cross section data. From the adjoint equation the optimum importance function can be derived, which can be used to devise a continuous-energy zero-variance Monte Carlo scheme. Key Words: transport problem, analytical solution, continuous energy, Monte Carlo 1.

J. Eduard Hoogenboom

2007-01-01T23:59:59.000Z

446

Research article: Monte Carlo-based rigid body modelling of large protein complexes against small angle scattering data  

Science Conference Proceedings (OSTI)

We present a modular, collaborative, open-source architecture for rigid body modelling based upon small angle scattering data, named sas_rigid. It is designed to provide a fast and extensible scripting interface using the easy-to-learn Python programming ... Keywords: Hemocyanin, Monte Carlo with simulated annealing, Rigid body modelling, Small angle scattering (SAS)

Christian Meesters; Bruno Pairet; Anja Rabenhorst; Heinz Decker; Elmar Jaenicke

2010-06-01T23:59:59.000Z

447

Senior Design Project Topics 2011 Project Title: Monte Carlo Simulations Using a Benchmark Full-Core Pressured Water  

E-Print Network (OSTI)

of approaches in parallel high performance computing that can potentially address the need to accelerate Monte level of 2.57 petaFLOPS by harvesting the power of 14,336 CPUs and 7,168 GPUs. The high performance computing industry is moving toward a hybrid computer model, where GPUs and CPUs work together to perform

Danon, Yaron

448

Expansion of the cathode spot and generation of shock waves in the plasma of a volume discharge in atmospheric-pressure helium  

SciTech Connect

The expansion of the cathode spot and the generation of shock waves during the formation and development of a pulsed volume discharge in atmospheric-pressure helium were studied by analyzing the emission spectra of the cathode plasma and the spatiotemporal behavior of the plasma glow. The transition of a diffuse volume discharge in a centimeter-long gap into a high-current diffuse mode when the gas pressure increased from 1 to 5 atm and the applied voltage rose from the statistical breakdown voltage to a 100% overvoltage was investigated. Analytical expressions for the radius of the cathode spot and its expansion velocity obtained in the framework of a spherically symmetric model agree satisfactorily with the experimental data.

Omarov, O. A.; Kurbanismailov, V. S.; Arslanbekov, M. A.; Gadzhiev, M. Kh.; Ragimkhanov, G. B.; Al-Shatravi, Ali J. G. [Dagestan State University (Russian Federation)

2012-01-15T23:59:59.000Z

449

Building A Simulation Model For The Prediction Of Temperature Distribution In Pulsed Laser Spot Welding Of Dissimilar Low Carbon Steel 1020 To Aluminum Alloy 6061  

Science Conference Proceedings (OSTI)

This paper describes the development of a computer model used to analyze the heat flow during pulsed Nd: YAG laser spot welding of dissimilar metal; low carbon steel (1020) to aluminum alloy (6061). The model is built using ANSYS FLUENT 3.6 software where almost all the environments simulated to be similar to the experimental environments. A simulation analysis was implemented based on conduction heat transfer out of the key hole where no melting occurs. The effect of laser power and pulse duration was studied.Three peak powers 1, 1.66 and 2.5 kW were varied during pulsed laser spot welding (keeping the energy constant), also the effect of two pulse durations 4 and 8 ms (with constant peak power), on the transient temperature distribution and weld pool dimension were predicated using the present simulation. It was found that the present simulation model can give an indication for choosing the suitable laser parameters (i.e. pulse durations, peak power and interaction time required) during pulsed laser spot welding of dissimilar metals.

Yousef, Adel K. M. [Faculty of Engineering , University of Diyala, Diyala-Baqouba (Iraq); Taha, Ziad A.; Shehab, Abeer A. [Institute of laser for postgraduate studies, Baghdad University, Baghdad (Iraq)

2011-01-17T23:59:59.000Z

450

Spot Scanning-Based Proton Therapy for Intracranial Meningioma: Long-Term Results From the Paul Scherrer Institute  

SciTech Connect

Background: To assess the long-term clinical results of spot scanning proton therapy (PT) in the treatment of intracranial meningiomas. Patients and Methods: Thirty-nine patients with meningioma (histologically proven 34/39) were treated with PT between July 1997 and January 2010. Thirty-two (82.1%) patients were treated as primary treatment (exclusive PT, n = 8; postoperative PT, n = 24). Mean age was 48.3 {+-} 17.9 years and 32 (82.1%) patients had skull base lesions. For patients undergoing surgery, 24 patients had a diagnosis of World Health Organization (WHO) Grade I and 10 of a WHO Grade II/III meningioma, respectively. The female-to-male ratio was 3.3. The median administered dose was 56.0 Gy (relative biologic effectiveness [RBE]) (range, 52.2-66.6) at 1.8-2.0 Gy (RBE) per fraction. Gross tumor volume (GTV) ranged from 0.76 to 546.5 cm{sup 3} (median, 21.5). Late toxicity was assessed according to Common Terminology Criteria for Adverse Events version 3.0. Mean follow-up time was 62.0 months and all patients were followed for >6 months. Results: Six patients presented with tumor recurrence and 6 patients died during follow-up, of which 4 of tumor progression. Five-year actuarial local control and overall survival rates were 84.8% and 81.8%, respectively, for the entire cohort and 100% for benign histology. Cumulative 5-year Grade {>=}3 late toxicity-free survival was 84.5%. On univariate analysis, LC was negatively influenced by WHO grade (p = 0.001), GTV (p = 0.013), and male gender (p = 0.058). Conclusions: PT is a safe and effective treatment for patients with untreated, recurrent, or incompletely resected intracranial meningiomas. WHO grade and tumor volume was an adverse prognostic factor for local control.

Weber, Damien C., E-mail: damien.weber@unige.ch [Radiation Oncology, Geneva University Hospital, Geneva (Switzerland); Schneider, Ralf; Goitein, Gudrun; Koch, Tamara; Ares, Carmen; Geismar, Jan H.; Schertler, Andreas; Bolsi, Alessandra; Hug, Eugen B. [Center for Proton Therapy, Paul Scherrer Institute, Viligen (Switzerland)

2012-07-01T23:59:59.000Z

451

Multi-Scale Multi-physics Methods Development for the Calculation of Hot-Spots in the NGNP  

Science Conference Proceedings (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

452

Audio Spots | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

U.S. Rep. Chuck Fleischmann, R-Tenn., discussed the recent formation of the House Science and National Laboratories Caucus. ORNL wins six R&D 100s ORNL wins six R&D 100s...

453

Friction Stir Spot Welding  

Science Conference Proceedings (OSTI)

Mar 3, 2011 ... Room: 5B Location: San Diego Conv. Ctr Session Chair: Anthony Reynolds, University of South Carolina; Michael West, South Dakota School ...

454

Is there a single spot size and grid for intensity modulated proton therapy? Simulation of head and neck, prostate and mesothelioma cases  

Science Conference Proceedings (OSTI)

Purpose: To assess the quality of dose distributions in real clinical cases for different dimensions of scanned proton pencil beams. The distance between spots (i.e., the grid of delivery) is optimized for each dimension of the pencil beam. Methods: The authors vary the {sigma} of the initial Gaussian size of the spot, from {sigma}{sub x} = {sigma}{sub y} = 3 mm to {sigma}{sub x} = {sigma}{sub y} = 8 mm, to evaluate the impact of the proton beam size on the quality of intensity modulated proton therapy (IMPT) plans. The distance between spots, {Delta}x and {Delta}y, is optimized on the spot plane, ranging from 4 to 12 mm (i.e., each spot size is coupled with the best spot grid resolution). In our Hyperion treatment planning system (TPS), constrained optimization is applied with respect to the organs at risk (OARs), i.e., the optimization tries to satisfy the dose objectives in the planning target volume (PTV) as long as all planning objectives for the OARs are met. Three-field plans for a nasopharynx case, two-field plans for a prostate case, and two-field plans for a malignant pleural mesothelioma case are considered in our analysis. Results: For the head and neck tumor, the best grids (i.e., distance between spots) are 5, 4, 6, 6, and 8 mm for {sigma} = 3, 4, 5, 6, and 8 mm, respectively. {sigma} {low dose and {sigma}{dose. For the prostate patient, the best grid is 4, 4, 5, 5, and 5 mm for {sigma} = 3, 4, 5, 6, and 8 mm, respectively. Beams with {sigma} > 3 mm did not satisfy our first clinical requirement that 95% of the prescribed dose is delivered to more than 95% of prostate and proximal seminal vesicles PTV. Our second clinical requirement, to cover the distal seminal vesicles PTV, is satisfied for beams as wide as {sigma} = 6 mm. For the mesothelioma case, the low dose PTV prescription is well respected for all values of {sigma}, while there is loss of high dose PTV coverage for {sigma} > 5 mm. The best grids have a spacing of 6, 7, 8, 9, and 12 mm for {sigma} = 3, 4, 5, 6, and 8 mm, respectively. Conclusions: The maximum acceptable proton pencil beam {sigma} depends on the volume treated, the protocol of delivery, and optimization of the plan. For the clinical cases, protocol and optimization used in this analysis, acceptable {sigma}s are {<=} 4 mm for the head and neck tumor, {<=} 3 mm for the prostate tumor and {<=} 6 mm for the malignant pleural mesothelioma. One can apply the same procedure used in this analysis when given a ''class'' of patients, a {sigma} and a clinical protocol to determine the optimal grid spacing.

Widesott, Lamberto; Lomax, Antony J.; Schwarz, Marco [AtreP, Agenzia Provinciale per la Protonterapia, 38122 Trento (Italy); Paul Scherrer Institute, 5232 Villigen (Switzerland); AtreP, Agenzia Provinciale per la Protonterapia, 38122 Trento (Italy)

2012-03-15T23:59:59.000Z

455

Lattice Monte Carlo calculations for unitary fermions in a harmonic trap  

Science Conference Proceedings (OSTI)

We present a lattice Monte Carlo approach developed for studying large numbers of strongly interacting nonrelativistic fermions and apply it to a dilute gas of unitary fermions confined to a harmonic trap. In place of importance sampling, our approach makes use of high statistics, an improved action, and recently proposed statistical techniques. We show how improvement of the lattice action can remove discretization and finite volume errors systematically. For N=3 unitary fermions in a box, our errors in the energy scale as the inverse lattice volume, and we reproduce a previous high-precision benchmark calculation to within our 0.3% uncertainty; as additional benchmarks we reproduce precision calculations of N=3,...,6 unitary fermions in a harmonic trap to within our {approx}1% uncertainty. We then use this action to determine the ground-state energies of up to 70 unpolarized fermions trapped in a harmonic potential on a lattice as large as 64{sup 3}x72. In contrast to variational calculations, we find evidence for persistent deviations from the thermodynamic limit for the range of N considered.

Endres, Michael G.; Kaplan, David B.; Lee, Jong-Wan; Nicholson, Amy N. [Physics Department, Columbia University, New York, New York 10027 (United States); Theoretical Research Division, RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1550 (United States)

2011-10-15T23:59:59.000Z

456

An Event-Driven Hybrid Molecular Dynamics and Direct Simulation Monte Carlo Algorithm  

Science Conference Proceedings (OSTI)

A novel algorithm is developed for the simulation of polymer chains suspended in a solvent. The polymers are represented as chains of hard spheres tethered by square wells and interact with the solvent particles with hard core potentials. The algorithm uses event-driven molecular dynamics (MD) for the simulation of the polymer chain and the interactions between the chain beads and the surrounding solvent particles. The interactions between the solvent particles themselves are not treated deterministically as in event-driven algorithms, rather, the momentum and energy exchange in the solvent is determined stochastically using the Direct Simulation Monte Carlo (DSMC) method. The coupling between the solvent and the solute is consistently represented at the particle level, however, unlike full MD simulations of both the solvent and the solute, the spatial structure of the solvent is ignored. The algorithm is described in detail and applied to the study of the dynamics of a polymer chain tethered to a hard wall subjected to uniform shear. The algorithm closely reproduces full MD simulations with two orders of magnitude greater efficiency. Results do not confirm the existence of periodic (cycling) motion of the polymer chain.

Donev, A; Garcia, A L; Alder, B J

2007-07-30T23:59:59.000Z

457

A First-Passage Kinetic Monte Carlo algorithm for complex diffusion-reaction systems  

Science Conference Proceedings (OSTI)

We develop an asynchronous event-driven First-Passage Kinetic Monte Carlo (FPKMC) algorithm for continuous time and space systems involving multiple diffusing and reacting species of spherical particles in two and three dimensions. The FPKMC algorithm presented here is based on the method introduced in Oppelstrup et al. and is implemented in a robust and flexible framework. Unlike standard KMC algorithms such as the n-fold algorithm, FPKMC is most efficient at low densities where it replaces the many small hops needed for reactants to find each other with large first-passage hops sampled from exact time-dependent Green's functions, without sacrificing accuracy. We describe in detail the key components of the algorithm, including the event-loop and the sampling of first-passage probability distributions, and demonstrate the accuracy of the new method. We apply the FPKMC algorithm to the challenging problem of simulation of long-term irradiation of metals, relevant to the performance and aging of nuclear materials in current and future nuclear power plants. The problem of radiation damage spans many decades of time-scales, from picosecond spikes caused by primary cascades, to years of slow damage annealing and microstructure evolution. Our implementation of the FPKMC algorithm has been able to simulate the irradiation of a metal sample for durations that are orders of magnitude longer than any previous simulations using the standard Object KMC or more recent asynchronous algorithms.

Donev, Aleksandar [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)], E-mail: aleks.donev@gmail.com; Bulatov, Vasily V. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Oppelstrup, Tomas [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Royal Institute of Technology (KTH), Stockholm S-10044 (Sweden); Gilmer, George H.; Sadigh, Babak; Kalos, Malvin H. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)

2010-05-01T23:59:59.000Z

458

Monte Carlo next-event point flux estimation for RCP01  

SciTech Connect

Two next event point estimators have been developed and programmed into the RCP01 Monte Carlo program for solving neutron transport problems in three-dimensional geometry with detailed energy description. These estimators use a simplified but accurate flux-at-a-point tallying technique. Anisotropic scattering in the lab system at the collision site is accounted for by determining the exit energy that corresponds to the angle between the location of the collision and the point detector. Elastic, inelastic, and thermal kernel scattering events are included in this formulation. An averaging technique is used in both estimators to eliminate the well-known problem of infinite variance due to collisions close to the point detector. In a novel approach to improve the estimator`s efficiency, a Russian roulette scheme based on anticipated flux fall off is employed where averaging is not appropriate. A second estimator successfully uses a simple rejection technique in conjunction with detailed tracking where averaging isn`t needed. Test results show good agreement with known numeric solutions. Efficiencies are examined as a function of input parameter selection and problem difficulty.

Martz, R.L.; Gast, R.C.; Tyburski, L.J.

1991-12-31T23:59:59.000Z

459

Monte Carlo Simulation of the Conversion X-Rays from the Electron Beam of PFMA-3  

SciTech Connect

PFMA-3, a dense Plasma Focus device, is being optimized as an X-ray generator. X-rays are obtained from the conversion of the electron beam emitted in the backward direction and driven to impinge on a 50 {mu}m brass foil. Monte Carlo simulations of the X-ray emission have been conducted with MCNPX. The electron spectrum had been determined experimentally and is used in the present work as input to the simulations. Dose to the brass foil has been determined both from simulations and from measurements with a thermographic camera, and the two results are found in excellent agreement, thus validating further the electron spectrum assumed as well as the simulation set-up. X-ray emission has been predicted both from bremsstrahlung and from characteristic lines. The spectrum has been found to be comprised of two components of which the one at higher energy, 30 divide 70 keV, is most useful for IORT applications. The results are necessary to estimate penetration in and dose to Standard Human Tissue.

Ceccolini, E.; Mostacci, D.; Sumini, M. [Montecuccolino Nuclear Engineering Laboratory, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); Rocchi, F. [Montecuccolino Nuclear Engineering Laboratory, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); UTFISSM-PRONOC, ENEA, via Martiri di Monte Sole 4, I-40129 Bologna (Italy); Tartari, A. [Department of Physics, University of Ferrara, Via Saragat 1, I-44122 Ferrara (Italy)

2011-12-13T23:59:59.000Z

460

A Monte Carlo Analysis of Gas Centrifuge Enrichment Plant Process Load Cell Data  

Science Conference Proceedings (OSTI)

As uranium enrichment plants increase in number, capacity, and types of separative technology deployed (e.g., gas centrifuge, laser, etc.), more automated safeguards measures are needed to enable the IAEA to maintain safeguards effectiveness in a fiscally constrained environment. Monitoring load cell data can significantly increase the IAEA s ability to efficiently achieve the fundamental safeguards objective of confirming operations as declared (i.e., no undeclared activities), but care must be taken to fully protect the operator s proprietary and classified information related to operations. Staff at ORNL, LANL, JRC/ISPRA, and University of Glasgow are investigating monitoring the process load cells at feed and withdrawal (F/W) stations to improve international safeguards at enrichment plants. A key question that must be resolved is what is the necessary frequency of recording data from the process F/W stations? Several studies have analyzed data collected at a fixed frequency. This paper contributes to load cell process monitoring research by presenting an analysis of Monte Carlo simulations to determine the expected errors caused by low frequency sampling and its impact on material balance calculations.

Garner, James R [ORNL; Whitaker, J Michael [ORNL

2013-01-01T23:59:59.000Z

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.


461

A Monte Carlo method of evaluating heterogeneous effects in plate-fueled reactors  

SciTech Connect

Few-group nuclear cross sections for small plate-fueled, light and heavy water test reactors are frequently generated with unit cell models that contain a homogeneous mixture of fuel, cladding, and water. The heterogeneous unit cells do not need to be represented explicitly for neutronics calculations when the plate and coolant channel thicknesses are small compared with the mean-free-path of neutrons. However, neutron and photon heating calculations were performed with heterogeneous fuel models to predict accurately the heat deposited in the fuel meat, cladding, and coolant. Heat deposited in the coolant channels and outside the fuel elements does not have a direct impact on the peak fuel meat temperature but must be included in the total coolant system heat balance. The results of a heterogeneous Monte Carlo calculation that estimates the heat loads in different fuel regions are presented and the fact that similar homogeneous fuel models can be used for many calculations. The calculations presented here were performed on models of the Advanced Neutron Source (ANS) and the Massachusetts Institute of Technology Reactor 2 (MITR-2). The ANS is a small, 362-MW (fission), plate-fueled, heavy water reactor designed to produce an intense steady-state source of neutrons.

Thayer, R.C.; Redmond, E.L. II; Ryskamp, J.M. (Idaho National Engineering Lab., Idaho Falls (United States))

1991-01-01T23:59:59.000Z

462

Monte Carlo simulation of photon buildup factors for shielding materials in diagnostic x-ray facilities  

SciTech Connect

Purpose: A simulation of buildup factors for ordinary concrete, steel, lead, plate glass, lead glass, and gypsum wallboard in broad beam geometry for photons energies from 10 keV to 150 keV at 5 keV intervals is presented. Methods: Monte Carlo N-particle radiation transport computer code has been used to determine the buildup factors for the studied shielding materials. Results: An example concretizing the use of the obtained buildup factors data in computing the broad beam transmission for tube potentials at 70, 100, 120, and 140 kVp is given. The half value layer, the tenth value layer, and the equilibrium tenth value layer are calculated from the broad beam transmission for these tube potentials. Conclusions: The obtained values compared with those calculated from the published data show the ability of these data to predict shielding transmission curves. Therefore, the buildup factors data can be combined with primary, scatter, and leakage x-ray spectra to provide a computationally based solution to broad beam transmission for barriers in shielding x-ray facilities.

Kharrati, Hedi; Agrebi, Amel; Karoui, Mohamed Karim [Ecole Superieure des Sciences et Techniques de la Sante de Monastir, Avenue Avicenne, 5000 Monastir (Tunisia); Faculte des Sciences de Monastir, 5000 Monastir (Tunisia)

2012-10-15T23:59:59.000Z

463

Composition PDF/photon Monte Carlo modeling of moderately sooting turbulent jet flames  

SciTech Connect

A comprehensive model for luminous turbulent flames is presented. The model features detailed chemistry, radiation and soot models and state-of-the-art closures for turbulence-chemistry interactions and turbulence-radiation interactions. A transported probability density function (PDF) method is used to capture the effects of turbulent fluctuations in composition and temperature. The PDF method is extended to include soot formation. Spectral gas and soot radiation is modeled using a (particle-based) photon Monte Carlo method coupled with the PDF method, thereby capturing both emission and absorption turbulence-radiation interactions. An important element of this work is that the gas-phase chemistry and soot models that have been thoroughly validated across a wide range of laminar flames are used in turbulent flame simulations without modification. Six turbulent jet flames are simulated with Reynolds numbers varying from 6700 to 15,000, two fuel types (pure ethylene, 90% methane-10% ethylene blend) and different oxygen concentrations in the oxidizer stream (from 21% O{sub 2} to 55% O{sub 2}). All simulations are carried out with a single set of physical and numerical parameters (model constants). Uniformly good agreement between measured and computed mean temperatures, mean soot volume fractions and (where available) radiative fluxes is found across all flames. This demonstrates that with the combination of a systematic approach and state-of-the-art physical models and numerical algorithms, it is possible to simulate a broad range of luminous turbulent flames with a single model. (author)

Mehta, R.S.; Haworth, D.C.; Modest, M.F. [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

2010-05-15T23:59:59.000Z

464

Statistical Properties of Nuclei by the Shell Model Monte Carlo Method  

E-Print Network (OSTI)

We use quantum Monte Carlo methods in the framework of the interacting nuclear shell model to calculate the statistical properties of nuclei at finite temperature and/or excitation energies. With this approach we can carry out realistic calculations in much larger configuration spaces than are possible by conventional methods. A major application of the methods has been the microscopic calculation of nuclear partition functions and level densities, taking into account both correlations and shell effects. Our results for nuclei in the mass region A ~ 50 - 70 are in remarkably good agreement with experimental level densities without any adjustable parameters and are an improvement over empirical formulas. We have recently extended the shell model theory of level statistics to higher temperatures, including continuum effects. We have also constructed simple statistical models to explain the dependence of the microscopically calculated level densities on good quantum numbers such as parity. Thermal signatures of pairing correlations are identified through odd-even effects in the heat capacity.

Y. Alhassid

2006-04-26T23:59:59.000Z

465

Self-Evolving Atomistic Kinetic Monte Carlo (SEAKMC): Fundamentals and Applications  

Science Conference Proceedings (OSTI)

The fundamentals of the framework and the details of each component of the self-evolving atomistic kinetic Monte Carlo (SEAKMC) are presented. The strength of this new technique is the ability to simulate dynamic processes with atomistic fidelity that is comparable to molecular dynamics (MD) but on a much longer time scale. The observation that the dimer method preferentially finds the saddle point (SP) with the lowest energy is investigated and found to be true only for defects with high symmetry. In order to estimate the fidelity of dynamics and accuracy of the simulation time, a general criterion is proposed and applied to two representative problems. Applications of SEAKMC for investigating the diffusion of interstitials and vacancies in bcc iron are presented and compared directly with MD simulations, demonstrating that SEAKMC provides results that formerly could be obtained only through MD. The correlation factor for interstitial diffusion in the dumbbell configuration, which is extremely difficult to obtain using MD, is predicted using SEAKMC. The limitations of SEAKMC are also discussed. The paper presents a comprehensive picture of the SEAKMC method in both its unique predictive capabilities and technically important details.

Xu, Haixuan [ORNL; Osetskiy, Yury N [ORNL; Stoller, Roger E [ORNL

2012-01-01T23:59:59.000Z

466

A high-fidelity Monte Carlo evaluation of CANDU-6 safety parameters  

Science Conference Proceedings (OSTI)

Important safety parameters such as the fuel temperature coefficient (FTC) and the power coefficient of reactivity (PCR) of the CANDU-6 (CANada Deuterium Uranium) reactor have been evaluated by using a modified MCNPX code. For accurate analysis of the parameters, the DBRC (Doppler Broadening Rejection Correction) scheme was implemented in MCNPX in order to account for the thermal motion of the heavy uranium nucleus in the neutron-U scattering reactions. In this work, a standard fuel lattice has been modeled and the fuel is depleted by using the MCNPX and the FTC value is evaluated for several burnup points including the mid-burnup representing a near-equilibrium core. The Doppler effect has been evaluated by using several cross section libraries such as ENDF/B-VI, ENDF/B-VII, JEFF, JENDLE. The PCR value is also evaluated at mid-burnup conditions to characterize safety features of equilibrium CANDU-6 reactor. To improve the reliability of the Monte Carlo calculations, huge number of neutron histories are considered in this work and the standard deviation of the k-inf values is only 0.5{approx}1 pcm. It has been found that the FTC is significantly enhanced by accounting for the Doppler broadening of scattering resonance and the PCR are clearly improved. (authors)

Kim, Y.; Hartanto, D. [Korea Advanced Inst. of Science and Technology KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

2012-07-01T23:59:59.000Z

467

MONTE CARLO SIMULATIONS OF THE PHOTOSPHERIC EMISSION IN GAMMA-RAY BURSTS  

Science Conference Proceedings (OSTI)

We studied the decoupling of photons from ultra-relativistic spherically symmetric outflows expanding with constant velocity by means of Monte Carlo simulations. For outflows with finite widths we confirm the existence of two regimes: photon-thick and photon-thin, introduced recently by Ruffini et al. (RSV). The probability density function of the last scattering of photons is shown to be very different in these two cases. We also obtained spectra as well as light curves. In the photon-thick case, the time-integrated spectrum is much broader than the Planck function and its shape is well described by the fuzzy photosphere approximation introduced by RSV. In the photon-thin case, we confirm the crucial role of photon diffusion, hence the probability density of decoupling has a maximum near the diffusion radius well below the photosphere. The time-integrated spectrum of the photon-thin case has a Band shape that is produced when the outflow is optically thick and its peak is formed at the diffusion radius.

Begue, D.; Siutsou, I. A.; Vereshchagin, G. V. [University of Roma ''Sapienza'', I-00185, p.le A. Moro 5, Rome (Italy)

2013-04-20T23:59:59.000Z

468

Monte Carlo analysis of a monolithic interconnected module with a back surface reflector  

DOE Green Energy (OSTI)

Recently, the photon Monte Carlo code, RACER-X, was modified to include wave-length dependent absorption coefficients and indices of refraction. This work was done in an effort to increase the code`s capabilities to be more applicable to a wider range of problems. These new features make RACER-X useful for analyzing devices like monolithic interconnected modules (MIMs) which have etched surface features and incorporates a back surface reflector (BSR) for spectral control. A series of calculations were performed on various MIM structures to determine the impact that surface features and component reflectivities have on spectral utilization. The traditional concern of cavity photonics is replaced with intra-cell photonics in the MIM design. Like the cavity photonic problems previously discussed, small changes in optical properties and/or geometry can lead to large changes in spectral utilization. The calculations show that seemingly innocuous surface features (e.g., trenches and grid lines) can significantly reduce the spectral utilization due to the non-normal incident photon flux. Photons that enter the device through a trench edge are refracted onto a trajectory where they will not escape. This leads to a reduction in the number of reflected below bandgap photons that return to the radiator and reduce the spectral utilization. In addition, trenches expose a lateral conduction layer in this particular series of calculations which increase the absorption of above bandgap photons in inactive material.

Ballinger, C.T.; Charache, G.W. [Lockheed Martin Corp., Schenectady, NY (United States); Murray, C.S. [Bettis Atomic Power Lab., West Mifflin, PA (United States)

1998-10-01T23:59:59.000Z