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Note: This page contains sample records for the topic "radiation transfer models" 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
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1

A Rapid Radiative Transfer Model for Reflection of Solar Radiation  

Science Conference Proceedings (OSTI)

A rapid analytical radiative transfer model for reflection of solar radiation in plane-parallel atmospheres is developed based on the Sobolev approach and the delta function transformation technique. A distinct advantage of this model over ...

X. Xiang; E. A. Smith; C. G. Justus

1994-07-01T23:59:59.000Z

2

Development of a 3D atmospheric radiative transfer model  

Science Conference Proceedings (OSTI)

The 3D atmospheric radiative transfer model is established based on MODTRAN4. Moreover, the methods of calculating the ratio of atmospheric transmission, path radiation and single scattering solar radiation are presented. This 3D model is running by ... Keywords: MODTRAN4, atmospheric radiative transfer model, infrared radiation

Zhifeng Lu; Ge Li; Gang Guo; Kedi Huang

2008-05-01T23:59:59.000Z

3

Cross Validation of Satellite Radiation Transfer Models during...  

Open Energy Info (EERE)

Cross Validation of Satellite Radiation Transfer Models during SWERA Project in Brazil (Abstract):This work describes the cross validation between two different...

4

Improvements to the SHDOM Radiative Transfer Modeling Package  

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

to the SHDOM Radiative Transfer Modeling Package K. F. Evans University of Colorado Boulder, Colorado W. J. Wiscombe National Aeronautics and Space Administration...

5

Community Radiative Transfer Model for Stratospheric Sounding Unit  

Science Conference Proceedings (OSTI)

To better use the Stratospheric Sounding Unit (SSU) data for reanalysis and climate studies, issues associated with the fast radiative transfer (RT) model for SSU have recently been revisited and the results have been implemented into the ...

Yong Chen; Yong Han; Quanhua Liu; Paul Van Delst; Fuzhong Weng

2011-06-01T23:59:59.000Z

6

Cross Validation of Satellite Radiation Transfer Models during SWERA  

Open Energy Info (EERE)

Cross Validation of Satellite Radiation Transfer Models during SWERA Cross Validation of Satellite Radiation Transfer Models during SWERA Project in Brazil Dataset Summary Description (Abstract): This work describes the cross validation between two different core radiation transfer models that will be applied during the SWERA (Solar and Wind Energy Assessment): the BRAZIL-SR, and the SUNY-Albany. The model cross validation was performed by using two reference sites in Brazil: at Caicó (06°28'01"S - 037°05'05"W,175.8 m), and Florianópolis (27°34'18"S - 048°31'42"W, 10 m), Satellite data were collected by INPE-CPTEC for GOES-8, that also provides for its quality assessment, sectoring, storing and distribution to the participating teams. In this work we show the first results of this cross-validation along with some discussions on model deviations

7

3D Atmospheric Radiative Transfer for Cloud System-Resolving Models: Forward Modelling and Observations  

SciTech Connect

Utilization of cloud-resolving models and multi-dimensional radiative transfer models to investigate the importance of 3D radiation effects on the numerical simulation of cloud fields and their properties.

Howard Barker; Jason Cole

2012-05-17T23:59:59.000Z

8

CROSS VALIDATION OF SATELLITE RADIATION TRANSFER MODELS DURING SWERA PROJECT  

Open Energy Info (EERE)

ISES- 2003 ISES- 2003 CROSS VALIDATION OF SATELLITE RADIATION TRANSFER MODELS DURING SWERA PROJECT IN BRAZIL Enio B. Pereira, Fernando R. Martins 1 Brazilian Institute for Space Research - INPE, São José dos Campos, 12245-970, SP, Brazil Phone + 55 12 39456741, Fax + 55 12 39456810, enio@dge.inpe.br Samuel L. Abreu, Hans Georg Beyer, Sergio Colle, and Solar Energy Laboratory - LABSOLAR - Department of Mechanical Engineering, Federal University of Santa Catarina -UFSC, Florianopolis, 88040-900, (SC), Brazil, Richard Perez The University at Albany (SUNY), ASRC-CESTM, Albany, 12203 (NY), USA Abstract - This work describes the cross validation between two different core radiation transfer models that will be applied during the SWERA (Solar and Wind Energy Assessment): the BRAZIL-SR, and the

9

Advances in Radiative Transfer Modeling in Support of Satellite Data Assimilation  

Science Conference Proceedings (OSTI)

Development of fast and accurate radiative transfer models for clear atmospheric conditions has enabled direct assimilation of clear-sky radiances from satellites in numerical weather prediction models. In this article, fast radiative transfer ...

Fuzhong Weng

2007-11-01T23:59:59.000Z

10

Modeling radiative transfer in photobioreactors for algal growth  

Science Conference Proceedings (OSTI)

Simulations of radiative transfer within an air-lift photobioreactor (PBR) are demonstrated by coupling it to the fluid hydrodynamics and employing wavelength dependant properties for the participating media. The radiative properties of the algal media ... Keywords: CFD, Computer simulation, Photobioreactor, Radiation transfer

Zachary C. Wheaton; Gautham Krishnamoorthy

2012-09-01T23:59:59.000Z

11

Radiative Transfer Modeling of a Coniferous Canopy Characterized by Airborne Remote Sensing  

Science Conference Proceedings (OSTI)

Solar radiation beneath a forest canopy can have large spatial variations, but this is frequently neglected in radiative transfer models for large-scale applications. To explicitly model spatial variations in subcanopy radiation, maps of canopy ...

Richard Essery; Peter Bunting; Aled Rowlands; Nick Rutter; Janet Hardy; Rae Melloh; Tim Link; Danny Marks; John Pomeroy

2008-04-01T23:59:59.000Z

12

Surface Solar Radiation Flux and Cloud Radiative Forcing for the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP): A Satellite, Surface Observations, and Radiative Transfer Model Study  

Science Conference Proceedings (OSTI)

This study presents surface solar radiation flux and cloud radiative forcing results obtained by using a combination of satellite and surface observations interpreted by means of a simple plane-parallel radiative transfer model called 2001. This ...

Catherine Gautier; Martin Landsfeld

1997-05-01T23:59:59.000Z

13

A 3-D multiband closure for radiation and neutron transfer moment models  

Science Conference Proceedings (OSTI)

We derive a 3D multi-band moment model and its associated closure for radiation and neutron transfer. The new closure is analytical and nonlinear but very simple. Its derivation is based on the maximum entropy closure and assumes a Wien shape for the ... Keywords: Maximum entropy closure, Moment models, Multi-band models, Multi-bin models, Neutron transfer, ODF, Radiative transfer

J. -F. Ripoll; A. A. Wray

2008-02-01T23:59:59.000Z

14

The Successive-Order-of-Interaction Radiative Transfer Model. Part II: Model Performance and Applications  

Science Conference Proceedings (OSTI)

Radiative transfer models for scattering atmospheres that are accurate yet computationally efficient are required for many applications, such as data assimilation in numerical weather prediction. The successive-order-of-interaction (SOI) model is ...

Christopher W. ODell; Andrew K. Heidinger; Thomas Greenwald; Peter Bauer; Ralf Bennartz

2006-10-01T23:59:59.000Z

15

Interpretation of AIRS Data in Thin Cirrus Atmospheres Based on a Fast Radiative Transfer Model  

Science Conference Proceedings (OSTI)

A thin cirrus cloud thermal infrared radiative transfer model has been developed for application to cloudy satellite data assimilation. This radiation model was constructed by combining the Optical Path Transmittance (OPTRAN) model, developed for ...

Qing Yue; K. N. Liou; S. C. Ou; B. H. Kahn; P. Yang; G. G. Mace

2007-11-01T23:59:59.000Z

16

An Improved Microwave Radiative Transfer Model for Tropical Oceanic Precipitation  

Science Conference Proceedings (OSTI)

In preparation for the launch of TRMM, new algorithms must be created that take advantage of the combined data from radar and microwave radiometers that will be on board the satellite. A microwave radiative transfer algorithm with a one-...

Jeffrey R. Tesmer; Thomas T. Wilheit

1998-05-01T23:59:59.000Z

17

A 3-D Canopy Radiative Transfer Model for Global Climate Modeling: Description, Validation and Application  

Science Conference Proceedings (OSTI)

The process of solar radiative transfer at the land surface is important to energy, water and carbon balance, especially for vegetated areas. Currently the most commonly used two-stream model considers the Plant Functional Types (PFTs) within a ...

Hua Yuan; Robert E. Dickinson; Yongjiu Dai; Muhammad J. Shaikh; Liming Zhou; Wei Shangguan; Duoying Ji

18

Cloudy Sky RRTM Shortwave Radiative Transfer and Comparison to the Revised ECMWF Shortwave Model  

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

Cloudy Sky RRTM Shortwave Radiative Transfer and Cloudy Sky RRTM Shortwave Radiative Transfer and Comparison to the Revised ECMWF Shortwave Model M. J. Iacono, J. S. Delamere, E. J. Mlawer, and S. A. Clough Atmospheric and Environmental Research, Inc. Lexington, Massachusetts J.-J. Morcrette European Centre for Medium-Range Weather Forecasts Reading, United Kingdom Introduction An important step toward improving radiative transfer codes in general circulation models (GCMs) is their thorough evaluation by comparison to measurements directly, or to other data-validated radiation models. This work extends the clear-sky shortwave (SW) GCM evaluation presented by Iacono et al. (2001) to computations including clouds. The rapid radiative transfer model (RRTM) SW radiation model accurately reproduces clear-sky direct beam fluxes from the Line-By-Line Radiative Transfer

19

A Radiation Fog Model with a Detailed Treatment of the Interaction between Radiative Transfer and Fog Microphysics  

Science Conference Proceedings (OSTI)

A one-dimensional radiation fog model is presented which includes a detailed description of the interaction between atmospheric radiative transfer and the microphysical structure of the fog. Aerosol particles and activated cloud droplets are ...

A. Bott; U. Sievers; W. Zdunkowski

1990-09-01T23:59:59.000Z

20

Validation of the Poisson Stochastic Radiative Transfer Model Against Cloud Cascade Models  

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

Poisson Stochastic Radiative Transfer Poisson Stochastic Radiative Transfer Model Against Cloud Cascade Models T. B. Zhuravleva Institute of Atmospheric Optics Tomsk, Russia A. Marshak National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt, Maryland Background Starting from a very simple stochastic cloud model by Mullamaa et al. (1972), several different stochastic models have been developed to describe radiative transfer regime in single-layer broken clouds (Kargin 1984; Titov 1990; Malvagi and Pomraning 1992; Barker et al. 1992; Malvagi et al. 1993; Kargin and Prigarin 1994; Prigarin and Titov 1996; Marshak et al. 1998; Prigarin et al. 1998, 2001; Evans et al. 1999, 2001). Recently Kassianov (2003a) generalized the Titov's (1990) stochastic model

Note: This page contains sample records for the topic "radiation transfer models" 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

An Update on Radiative Transfer Model Development at Atmospheric and Environmental Research, Inc.  

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

Update on Radiative Transfer Model Development at Update on Radiative Transfer Model Development at Atmospheric and Environmental Research, Inc. J. S. Delamere, S. A. Clough, E. J. Mlawer, Sid-Ahmed Boukabara, K. Cady-Pereira, and M. Shepard Atmospheric and Environmental Research, Inc. Lexington, Maine Introduction Over the last decade, a suite of radiative transfer models has been developed at Atmospheric and Environmental Research, Inc. (AER) with support from the Atmospheric and Radiation Measurement (ARM) Program. These models span the full spectral regime from the microwave to the ultraviolet, and range from monochromatic to band calculations. Each model combines the latest spectroscopic advancements with radiative transfer algorithms to efficiently compute radiances, fluxes, and cooling

22

Assessing 1D Atmospheric Solar Radiative Transfer Models: Interpretation and Handling of Unresolved Clouds  

Science Conference Proceedings (OSTI)

The primary purpose of this study is to assess the performance of 1D solar radiative transfer codes that are used currently both for research and in weather and climate models. Emphasis is on interpretation and handling of unresolved clouds. ...

H. W. Barker; G. L. Stephens; P. T. Partain; J. W. Bergman; B. Bonnel; K. Campana; E. E. Clothiaux; S. Clough; S. Cusack; J. Delamere; J. Edwards; K. F. Evans; Y. Fouquart; S. Freidenreich; V. Galin; Y. Hou; S. Kato; J. Li; E. Mlawer; J.-J. Morcrette; W. O'Hirok; P. Risnen; V. Ramaswamy; B. Ritter; E. Rozanov; M. Schlesinger; K. Shibata; P. Sporyshev; Z. Sun; M. Wendisch; N. Wood; F. Yang

2003-08-01T23:59:59.000Z

23

Change in regime and transfer function models of global solar radiation in Kuwait  

Science Conference Proceedings (OSTI)

The development of the models for global solar radiation in Kuwait is based on removing the annual periodicity and seasonal variation. The first methodology used here is the change in regime technique that relies on dividing the observations into two ... Keywords: ARMA model, Harmonic analysis, Solar radiation, Transfer function

S. A. Al-Awadhi

2005-09-01T23:59:59.000Z

24

Original article: Comparison of numerical models in radiative heat transfer with application to circuit-breaker simulations  

Science Conference Proceedings (OSTI)

Two different modeling approaches for the numerical computation of the radiation energy exchange in the context of the simulation of high-voltage circuit breakers are investigated. These are the basic Radiative Transfer Equation method and the P1 model ... Keywords: CFD modeling, Circuit breakers, Finite volume discretization, P1 model, Radiative heat transfer

Matthieu Melot; Jean-Yves TrPanier; Ricardo Camarero; Eddy Petro

2012-08-01T23:59:59.000Z

25

Cross-Validation of SWERA's Core Radiative Transfer Models - Partial Report  

Open Energy Info (EERE)

Cross-Validation of SWERA's Core Radiative Transfer Models - Partial Report Cross-Validation of SWERA's Core Radiative Transfer Models - Partial Report Dataset Summary Description (Abstract): This partial report describes the results obtained by two of the core radiative transfer models adopted in the SWERA Project for global horizontal solar irradiation during the cross-validation step. They are BRASIL-SR and SUNY-ALBANY models (Martins, 2001; Stuhlmann et al. 1990; Perez et al., 2002). The results from other two other core models, NREL and DLR, are not yet available. The HELIOSAT was included as a reference model at this stage. The HELIOSAT model is widely employed for solar energy assessment in Europe and is well know by the solar energy community worldwide (Beyer et al., 1996; Cano et al., 1986). (Purpose): SWERA solar cross-validation study

26

A Three-Dimensional Radiative Transfer Model to Investigate the Solar Radiation within a Cloudy Atmosphere. Part I: Spatial Effects  

Science Conference Proceedings (OSTI)

A new Monte Carlobased three-dimensional (3D) radiative transfer model of high spectral and spatial resolution is presented. It is used to investigate the difference in broadband solar radiation absorption, top-of-the-atmosphere upwelling, and ...

William OHirok; Catherine Gautier

1998-06-01T23:59:59.000Z

27

A Three-Dimensional Radiative Transfer Model to Investigate the Solar Radiation within a Cloudy Atmosphere. Part II: Spectral Effects  

Science Conference Proceedings (OSTI)

In this second part of a two-part paper, the spectral response of the interaction between gases, cloud droplets, and solar radiation is investigated using a Monte Carlo-based three-dimensional (3D) radiative transfer model with a spectral ...

William OHirok; Catherine Gautier

1998-10-01T23:59:59.000Z

28

Physically Based Satellite Retrieval of Precipitation Using a 3D Passive Microwave Radiative Transfer Model  

Science Conference Proceedings (OSTI)

A precipitation retrieval algorithm based on the application of a 3D radiative transfer model to a hybrid physical-stochastic 3D cloud model is described. The cloud model uses a statistical rainfall clustering scheme to generate 3D cloud ...

J. L. Haferman; E. N. Anagnostou; D. Tsintikidis; W. F. Krajewski; T. F. Smith

1996-08-01T23:59:59.000Z

29

Intercomparison of Radiation Transfer Models Representing Direct Shortwave Forcing by Sulfate Aerosols  

E-Print Network (OSTI)

A study has been conducted, involving 15 models by 12 groups, to compare modeled forcing (change in shortwave radiation budget) due to sulfate aerosol for a wide range of values of particle radius, optical depth, surface albedo, and solar zenith angle (SZA). The models included high- and low-spectral resolution models, incorporating a variety of radiative transfer approximations, as well as a line-by-line model. The normalized forcings (forcing per sulfate column burden) obtained with the radiative transfer models were examined and the differences characterized. All models simulate forcings of comparable amplitude and exhibit a similar dependence on input parameters. As expected for a non-light-absorbing aerosol, forcings were negative (cooling influence), except at high surface albedo combined with low SZA. The relative standard deviation of the zenith-angle-average normalized broadband forcing for 15 models was 8% for particle radius near the maximum in magnitude of this forcing (ca....

Sulfate Aerosols; Stephen E Schwartz

1998-01-01T23:59:59.000Z

30

Development and Evaluation of RRTMG_SW, a Shortwave Radiative Transfer Model for GCM Applications  

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

Development and Evaluation of RRTMG_SW, Development and Evaluation of RRTMG_SW, a Shortwave Radiative Transfer Model for General Circulation Model Applications M. J. Iacono, J. S. Delamere, E. J. Mlawer, and S. A. Clough Atmospheric and Environmental Research, Inc. Lexington, Massachusetts J.-J. Morcrette European Center for Medium-Range Weather Forecasts Reading, United Kingdom Y.-T. Hou National Centers for Environmental Prediction Camp Springs, Maryland Introduction The k-distribution shortwave radiation model developed for the Atmospheric Radiation Measurement (ARM) Program, RRTM_SW_V2.4 (Clough et al. 2004), utilizes the discrete ordinates radiative transfer model, DISORT, for scattering calculations and 16 g-points in each of its 16 spectral bands. DISORT provides agreement with line-by-line flux calculations to within 1 Wm

31

paNTICA: A Fast 3D Radiative Transfer Scheme to Calculate Surface Solar Irradiance for NWP and LES Models  

Science Conference Proceedings (OSTI)

The resolution of numerical weather prediction models is constantly increasing, making it necessary to consider three-dimensional radiative transfer effects such as cloud shadows cast into neighboring grid cells and thus affecting radiative ...

Ulrike Wissmeier; Robert Buras; Bernhard Mayer

2013-08-01T23:59:59.000Z

32

A Computation of the Stratospheric Diabatic Circulation Using an Accurate Radiative Transfer Model  

Science Conference Proceedings (OSTI)

The global diabatic circulation is computed for the months of January, April, July and October over the altitude region 100 to 0.1 mb using an accurate troposphere-stratosphere radiative transfer model, SBUV and SME ozone data, and NMC ...

Joan E. Rosenfield; Mark R. Schoeberl; Marvin A. Geller

1987-03-01T23:59:59.000Z

33

Accounting for Unresolved Clouds in a 1D Infrared Radiative Transfer Model. Part I: Solution for Radiative Transfer, Including Cloud Scattering and Overlap  

Science Conference Proceedings (OSTI)

Various aspects of infrared radiative transfer through clouds are investigated. First, three solutions to the IR radiative transfer equation are presented and assessed, each corresponding to a different approximation for the Planck function. It ...

J. Li

2002-12-01T23:59:59.000Z

34

A Systematic Study of Longwave Radiative Heating and Cooling within Valleys and Basins Using a Three-Dimensional Radiative Transfer Model  

Science Conference Proceedings (OSTI)

The Monte Carlo code for the physically correct tracing of photons in cloudy atmospheres (MYSTIC) three-dimensional radiative transfer model was used in a parametric study to determine the strength of longwave radiative heating and cooling in ...

Sebastian W. Hoch; C. David Whiteman; Bernhard Mayer

2011-12-01T23:59:59.000Z

35

Global Calibration of the GEOS-5 L-Band Microwave Radiative Transfer Model over Nonfrozen Land Using SMOS Observations  

Science Conference Proceedings (OSTI)

A zero-order (tau-omega) microwave radiative transfer model (RTM) is coupled to the Goddard Earth Observing System, version 5 (GEOS-5) catchment land surface model in preparation for the future assimilation of global brightness temperatures (Tb) ...

Gabrille J. M. De Lannoy; Rolf H. Reichle; Valentijn R. N. Pauwels

2013-06-01T23:59:59.000Z

36

The Gastropod Fast Radiative Transfer Model for Advanced Infrared Sounders and Characterization of Its Errors for Radiance Assimilation  

Science Conference Proceedings (OSTI)

Principal aspects of the development of Gastropod, a fixed-pressure-grid fast radiative transfer model for the Atmospheric Infrared Sounder (AIRS), are described. Performance of the forward and gradient operators is characterized, and the impact ...

V. Sherlock; A. Collard; S. Hannon; R. Saunders

2003-12-01T23:59:59.000Z

37

Hyperspectral Aquatic Radiative Transfer Modeling Using a High-Performance Cluster Computing Based Approach  

SciTech Connect

For aquatic studies, radiative transfer (RT) modeling can be used to compute hyperspectral above-surface remote sensing reflectance that can be utilized for inverse model development. Inverse models can provide bathymetry and inherent- and bottom-optical property estimation. Because measured oceanic field/organic datasets are often spatio-temporally sparse, synthetic data generation is useful in yielding sufficiently large datasets for inversion model development; however, these forward-modeled data are computationally expensive and time-consuming to generate. This study establishes the magnitude of wall-clock-time savings achieved for performing large, aquatic RT batch-runs using parallel computing versus a sequential approach. Given 2,600 simulations and identical compute-node characteristics, sequential architecture required {approx}100 hours until termination, whereas a parallel approach required only {approx}2.5 hours (42 compute nodes) - a 40x speed-up. Tools developed for this parallel execution are discussed.

Fillippi, Anthony [Texas A& M University; Bhaduri, Budhendra L [ORNL; Naughton, III, Thomas J [ORNL; King, Amy L [ORNL; Scott, Stephen L [ORNL; Guneralp, Inci [Texas A& M University

2012-01-01T23:59:59.000Z

38

Hyperspectral Aquatic Radiative Transfer Modeling Using a High-Performance Cluster Computing-Based Approach  

SciTech Connect

Abstract For aquatic studies, radiative transfer (RT) modeling can be used to compute hyperspectral above-surface remote sensing reflectance that can be utilized for inverse model development. Inverse models can provide bathymetry and inherent-and bottom-optical property estimation. Because measured oceanic field/organic datasets are often spatio-temporally sparse, synthetic data generation is useful in yielding sufficiently large datasets for inversion model development; however, these forward-modeled data are computationally expensive and time-consuming to generate. This study establishes the magnitude of wall-clock-time savings achieved for performing large, aquatic RT batch-runs using parallel computing versus a sequential approach. Given 2,600 simulations and identical compute-node characteristics, sequential architecture required ~100 hours until termination, whereas a parallel approach required only ~2.5 hours (42 compute nodes) a 40x speed-up. Tools developed for this parallel execution are discussed.

Filippi, Anthony M [ORNL; Bhaduri, Budhendra L [ORNL; Naughton, III, Thomas J [ORNL; King, Amy L [ORNL; Scott, Stephen L [ORNL; Guneralp, Inci [Texas A& M University

2012-01-01T23:59:59.000Z

39

Computation of Domain-Averaged Irradiance with a Simple Two-Stream Radiative Transfer Model Including Vertical Cloud Property Correlations  

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

Computation of Domain-Averaged Irradiance Computation of Domain-Averaged Irradiance with a Simple Two-Stream Radiative Transfer Model Including Vertical Cloud Property Correlations S. Kato Center for Atmospheric Sciences Hampton University Hampton, Virginia Introduction Recent development of remote sensing instruments by Atmospheric Radiation Measurement (ARM?) Program provides information of spatial and temporal variability of cloud structures. However it is not clear what cloud properties are required to express complicated cloud fields in a realistic way and how to use them in a relatively simple one-dimensional (1D) radiative transfer model to compute the domain averaged irradiance. To address this issue, a simple shortwave radiative transfer model that can treat the vertical cloud optical property correlation is developed. The model is based on the gamma-weighted

40

Impact of Changes to the Radiation Transfer Parameterizations Plus Cloud Optical. Properties in the ECMWF Model  

Science Conference Proceedings (OSTI)

A new radiation package, shown to correct most of the systematic errors of the operational ECMWF radiation scheme, has been extensively tested in the ECMWF forecast model. Improvements in the clear-sky fluxes and radiative heating/cooling rate ...

Jean-Jacques Morcrette

1990-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Three-dimensional dust radiative-transfer models: The Pinwheel Nebula of WR104  

E-Print Network (OSTI)

We present radiative-transfer modelling of the dusty spiral Pinwheel Nebula observed around the Wolf-Rayet/OB-star binary WR104. The models are based on the three-dimensional radiative-transfer code TORUS, modified to include an adaptive mesh that allows us to adequately resolve both the inner spiral turns (sub-AU scales) and the outer regions of the nebula (distances of 10^4 AU from the central source). The spiral model provides a good fit to both the spectral energy distribution and Keck aperture masking interferometry, reproducing both the maximum entropy recovered images and the visibility curves. We deduce a dust creation rate of 8+-1 x 10^{-7} solar masses per year, corresponding to approximately 2% by mass of the carbon produced by the Wolf-Rayet star. Simultaneous modelling of the imaging and spectral data enables us to constrain both the opening-angle of the wind-wind collision interface and the dust grain size. We conclude that the dust grains in the inner part of the Pinwheel nebula are small (~100A), in agreement with theoretical predictions, although we cannot rule out the presence of larger grains (~1 micron) further from the central binary. The opening angle of the wind-wind collision interface appears to be about 40 degrees, in broad agreement with the wind parameters estimated for the central binary. We discuss the success and deficiencies of the model, and the likely benefits of applying similar techniques to the more the more complex nebulae observed around other WR/O star binaries.

Tim J Harries; John D Monnier; Neil H Symington; Ryuichi Kurosawa

2004-01-27T23:59:59.000Z

42

Thermal-radiation heat-transfer model for degraded cores. [PWR; BWR  

SciTech Connect

One consequence of the accident at the Three Mile Island Unit 2 (TMI-2) nuclear power plant is a realization by the nuclear power technical community that there is a need for calculational tools that can be used to analyze the TMI-2 accident and to investigate hypothetical situations involving degraded light-water reactor (LWR) cores. As a result, there are now several ongoing modeling and code development efforts in the United States among which is the development of the MIMAS (Multifield Integrated Meltdown Analysis System code) at the Los Alamos National Laboratory. This paper describes a thermal-radiation heat-transfer model for LWR degraded cores that has been developed for the MIMAS code.

Tomkins, J.L.

1983-01-01T23:59:59.000Z

43

3-D Radiative Transfer Modeling of Structured Winds in Massive Hot Stars with Wind3D  

E-Print Network (OSTI)

We develop 3-D models of the structured winds of massive hot stars with the Wind3D radiative transfer (RT) code. We investigate the physical properties of large-scale structures observed in the wind of the B-type supergiant HD 64760 with detailed line profile fits to Discrete Absorption Components (DACs) and rotational modulations observed with IUE in Si IV {\\lambda}1395. We develop parameterized input models Wind3D with large-scale equatorial wind density- and velocity-structures, or so-called `Co-rotating Interaction Regions' (CIRs) and `Rotational Modulation Regions' (RMRs). The parameterized models offer important advantages for high-performance RT calculations over ab-initio hydrodynamic input models. The acceleration of the input model calculations permits us to simulate and investigate a wide variety of physical conditions in the extended winds of massive hot stars. The new modeling method is very flexible for constraining the dynamic and geometric wind properties of RMRs in HD 64760. We compute that t...

Lobel, A; Blomme, R

2010-01-01T23:59:59.000Z

44

The Angular Distribution of UV-B Sky Radiance under Cloudy Conditions: A Comparison of Measurements and Radiative Transfer Calculations Using a Fractal Cloud Model  

Science Conference Proceedings (OSTI)

In recent years, global warming concerns have focused attention on cloud radiative forcing and its accurate encapsulation in radiative transfer measurement and modeling programs. At present, this process is constrained by the dynamic movement and ...

Christopher Kuchinke; Kurt Fienberg; Manuel Nunez

2004-05-01T23:59:59.000Z

45

A Discrete Ordinate, Multiple Scattering, Radiative Transfer Model of the Venus Atmosphere from 0.1 to 260 ?m  

Science Conference Proceedings (OSTI)

The authors describe a new radiative transfer model of the Venus atmosphere (RTM) that includes optical properties from nine gases and four cloud modes between 0.1 and 260 ?m. A multiple-stream discrete ordinate flux solver is used to calculate ...

Christopher Lee; Mark Ian Richardson

2011-06-01T23:59:59.000Z

46

Radiative Transfer to Space through a Precipitating Cloud at Multiple Microwave Frequencies. Part I: Model Description  

Science Conference Proceedings (OSTI)

In a two-part study we investigate the impact of time-dependent cloud microphysical structure on the transfer to space of passive microwave radiation at several frequencies across the EHF and lower SHF portions of the microwave spectrum in order ...

Alberto Mugnai; Eric A. Smith

1988-09-01T23:59:59.000Z

47

Stochastic Radiative Transfer in Partially Cloudy Atmosphere  

Science Conference Proceedings (OSTI)

A radiation treatment of the broken-cloud problem is presented, based upon various stochastic models of the equation of radiative transfer that consider the clouds and clear sky as a two-component mixture. These models, recently introduced in the ...

F. Malvagi; R. N. Byrne; G. C. Pomraning; R. C. J. Somerville

1993-07-01T23:59:59.000Z

48

Parameterization of Atmospheric Radiative Transfer. Part I: Validity of Simple Models  

Science Conference Proceedings (OSTI)

This paper outlines a radiation parameterization method for deriving broadband fluxes that is currently being implemented in a number of global and regional atmospheric models. The rationale for the use of the 2-stream method as a way of solving ...

Graeme L. Stephens; Philip M. Gabriel; Philip T. Partain

2001-11-01T23:59:59.000Z

49

Investigation of Thin Cirrus Cloud Optical and Microphysical Properties on the Basis of Satellite Observations and Fast Radiative Transfer Models  

E-Print Network (OSTI)

This dissertation focuses on the global investigation of optically thin cirrus cloud optical thickness (tau) and microphysical properties, such as, effective particle size (D_(eff)) and ice crystal habits (shapes), based on the global satellite observations and fast radiative transfer models (RTMs). In the first part, we develop two computationally efficient RTMs simulating satellite observations under cloudy-sky conditions in the visible/shortwave infrared (VIS/SWIR) and thermal inferred (IR) spectral regions, respectively. To mitigate the computational burden associated with absorption, thermal emission and multiple scattering, we generate pre-computed lookup tables (LUTs) using two rigorous models, i.e., the line-by-line radiative transfer model (LBLRTM) and the discrete ordinates radiative transfer model (DISORT). The second part introduces two methods (i.e., VIS/SWIR- and IR-based methods) to retrieve tau and D_(eff) from satellite observations in corresponding spectral regions of the two RTMs. We discuss the advantages and weakness of the two methods by estimating the impacts from different error sources on the retrievals through sensitivity studies. Finally, we develop a new method to infer the scattering phase functions of optically thin cirrus clouds in a water vapor absorption channel (1.38-m). We estimate the ice crystal habits and surface structures by comparing the inferred scattering phase functions and numerically simulated phase functions calculated using idealized habits.

Wang, Chenxi

2013-08-01T23:59:59.000Z

50

An Iterative Radiative Transfer Code For Ocean-Atmosphere Systems  

Science Conference Proceedings (OSTI)

We describe the details of an iterative radiative transfer code for computing the intensity and degree of polarization of diffuse radiation in models of the ocean-atmosphere system. The present code neglects the upwelling radiation from below the ...

Ziauddin Ahmad; Robert S. Fraser

1982-03-01T23:59:59.000Z

51

Using a Parameterization of a Radiative Transfer Model to Build High-Resolution Maps of Typical Clear-Sky UV Index in Catalonia, Spain  

Science Conference Proceedings (OSTI)

To perform a climatic analysis of the annual UV index (UVI) variations in Catalonia, Spain (northeast of the Iberian Peninsula), a new simple parameterization scheme is presented based on a multilayer radiative transfer model. The ...

Jordi Badosa; Josep-Abel Gonzlez; Josep Calb; Michiel van Weele; Richard L. McKenzie

2005-06-01T23:59:59.000Z

52

Modeling near-field radiative heat transfer from sharp objects using a general three-dimensional numerical scattering technique  

E-Print Network (OSTI)

We develop a general numerical method to calculate the nonequilibrium radiative heat transfer between a plate and compact objects of arbitrary shapes, making the first accurate theoretical predictions for the total heat ...

McCauley, Alexander Patrick

53

Retrieval of Sea Surface Temperature from Space, Based on Modeling of Infrared Radiative Transfer: Capabilities and Limitations  

Science Conference Proceedings (OSTI)

The retrieval (estimation) of sea surface temperatures (SSTs) from space-based infrared observations is increasingly performed using retrieval coefficients derived from radiative transfer simulations of top-of-atmosphere brightness temperatures (...

Christopher J. Merchant; Pierre Le Borgne

2004-11-01T23:59:59.000Z

54

N-Stream Approximations to Radiative Transfer  

Science Conference Proceedings (OSTI)

Schuster's two-stream approximation is first derived from Chandrasekhar's radiative transfer equation, and then generalized to an arbitrary number of streams. The resulting technique for solving the transfer equation that is similar to the ...

Charles Acquista; Frederick House; James Jafolla

1981-07-01T23:59:59.000Z

55

Retrieval of Ice Cloud Properties from AIRS and MODIS Observations Based on a Fast High-Spectral-Resolution Radiative Transfer Model  

Science Conference Proceedings (OSTI)

A computationally efficient high-spectral-resolution cloudy-sky radiative transfer model (HRTM) in the thermal infrared region (7001300 cm?1, 0.1 cm?1 spectral resolution) is advanced for simulating the upwelling radiance at the top of atmosphere ...

Chenxi Wang; Ping Yang; Steven Platnick; Andrew K. Heidinger; Bryan A. Baum; Thomas Greenwald; Zhibo Zhang; Robert E. Holz

2013-03-01T23:59:59.000Z

56

Using radiative transfer equation to model absorption by thin Cu(In,Ga)Se2  

E-Print Network (OSTI)

on Photovoltaic Energy Conversion, K. Kurokawa ed. (Arisumi, Osaka, Japan, 2003), pp. 344­347. 10. F. Leblanc, J European Photovoltaic Solar Energy Conference, James & James ed. (Alden, Glasgow, UK, 2000), pp. 522 thin film silicon solar cells: optical model," in 16th European Photovoltaic Solar Energy Conference

57

Two-Dimensional Radiative Transfer in Cloudy Atmospheres: The Spherical Harmonic Spatial Grid Method  

Science Conference Proceedings (OSTI)

A new two-dimensional monochromatic method that computes the transfer of solar or thermal radiation through atmospheres with arbitrary optical properties is described. The model discretizes the radiative transfer equation by expanding the angular ...

K. Franklin Evans

1993-09-01T23:59:59.000Z

58

Scalable photon monte carlo algorithms and software for the solution of radiative heat transfer problems  

Science Conference Proceedings (OSTI)

Radiative heat transfer plays a central role in many combustion and engineering applications. Because of its highly nonlinear and nonlocal nature, the computational cost can be extremely high to model radiative heat transfer effects accurately. In this ...

Ivana Veljkovic; Paul E. Plassmann

2005-09-01T23:59:59.000Z

59

Radiative heat transfer between dielectric bodies  

E-Print Network (OSTI)

The recent development of a scanning thermal microscope (SThM) has led to measurements of radiative heat transfer between a heated sensor and a cooled sample down to the nanometer range. This allows for comparision of the known theoretical description of radiative heat transfer, which is based on fluctuating electrodynamics, with experiment. The theory itself is a macroscopic theory, which can be expected to break down at distances much smaller than 10-8m. Against this background it seems to be reasonable to revisit the known macroscopic theory of fluctuating electrodynamics and of radiative heat transfer.

Svend-Age Biehs

2011-03-16T23:59:59.000Z

60

Radiative Heat Transfer between Neighboring Particles  

E-Print Network (OSTI)

The near-field interaction between two neighboring particles is known to produce enhanced radiative heat transfer. We advance in the understanding of this phenomenon by including the full electromagnetic particle response, heat exchange with the environment, and important radiative corrections both in the distance dependence of the fields and in the particle absorption coefficients. We find that crossed terms of electric and magnetic interactions dominate the transfer rate between gold and SiC particles, whereas radiative corrections reduce it by several orders of magnitude even at small separations. Radiation away from the dimer can be strongly suppressed or enhanced at low and high temperatures, respectively. These effects must be taken into account for an accurate description of radiative heat transfer in nanostructured environments.

Alejandro Manjavacas; F. Javier Garcia de Abajo

2012-01-26T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Development of a second-generation regional climate model (RegCM2). Part I: Boundary-layer and radiative transfer processes  

SciTech Connect

During the last few years the development of a second-generation regional climate modeling system (RegCM2) has been completed at the National Center for Atmospheric Research (NCAR). Based upon the National Center for Atmospheric Research-Pennsylvania State University Mesoscale Model (MM4), RegCM2 includes improved formulations of boundary layer, radiative transfer, surface physics, cumulus convection, and time integration technique, which make it more physically comprehensive and more computationally efficient than the previous regional climate model version. This paper discusses a number of month-long simulations over the European region that were conducted to test the new RegCM2 boundary-layer parameterization (the scheme developed by Holtsag et al.) and radiative transfer formulation [the package developed for the NCAR Community Climate Model 2 (CCM2)]. Both schemes significantly affect the model precipitation, temperature, moisture, and cloudiness climatology, leading to overall more realistic results, while they do not substantially modify the model performance in simulating the aggregated characteristics of synoptic patterns. Description of the convective processes and procedures of boundary condition assimilation included in RegCM2 is presented in companion paper by Giorgi et al. 26 refs., 11 figs., 10 tabs.

Giorgi, F.; Marinucci, M.R.; Bates, G.T. (National Center for Atmospheric Research, Boulder, CO (United States))

1993-10-01T23:59:59.000Z

62

Atmospheric Longwave Irradiance Uncertainty: Pyrgeometers Compared to an Absolute Sky-Scanning Radiometer, Atmospheric Emitted Radiance Interferometer, and Radiative Transfer Model Calculations  

SciTech Connect

Because atmospheric longwave radiation is one of the most fundamental elements of an expected climate change, there has been a strong interest in improving measurements and model calculations in recent years. Important questions are how reliable and consistent are atmospheric longwave radiation measurements and calculations and what are the uncertainties? The First International Pyrgeometer and Absolute Sky-scanning Radiometer Comparison, which was held at the Atmospheric Radiation Measurement program's Souther Great Plains site in Oklahoma, answers these questions at least for midlatitude summer conditions and reflects the state of the art for atmospheric longwave radiation measurements and calculations. The 15 participating pyrgeometers were all calibration-traced standard instruments chosen from a broad international community. Two new chopped pyrgeometers also took part in the comparison. And absolute sky-scanning radiometer (ASR), which includes a pyroelectric detector and a reference blackbody source, was used for the first time as a reference standard instrument to field calibrate pyrgeometers during clear-sky nighttime measurements. Owner-provided and uniformly determined blackbody calibration factors were compared. Remarkable improvements and higher pyrgeometer precision were achieved with field calibration factors. Results of nighttime and daytime pyrgeometer precision and absolute uncertainty are presented for eight consecutive days of measurements, during which period downward longwave irradiance varied between 260 and 420 W m-2. Comparisons between pyrgeometers and the absolute ASR, the atmospheric emitted radiance interferometer, and radiative transfer models LBLRTM and MODTRAN show a surprisingly good agreement of <2 W m-2 for nighttime atmospheric longwave irradiance measurements and calculations.

Philipona, J. R.; Dutton, Ellsworth G.; Stoffel, T.; Michalsky, Joseph J.; Reda, I.; Stifter, Armin; Wendling, Peter; Wood, Norm; Clough, Shepard A.; Mlawer, Eli J.; Anderson, Gail; Revercomb, Henry E.; Shippert, Timothy R.

2001-06-04T23:59:59.000Z

63

An Earth Outgoing Longwave Radiation Climate Model. Part II: Radiation with Clouds Included  

Science Conference Proceedings (OSTI)

An Earth outgoing longwave radiation (OLWR) climate model was constructed for radiation budget studies. The model consists of the upward radiative transfer parameterization of Thompson and Warren, the cloud cover model of Sherr et al., and a ...

Shi-Keng Yang; G. Louis Smith; Fred L. Bartman

1988-10-01T23:59:59.000Z

64

Radiative Heat Transfer Analysis within Three-Dimensional Clouds Subjected to Solar and Sky Irradiation  

Science Conference Proceedings (OSTI)

A three-dimensional radiative heat transfer analysis of an arbitrary-shaped modeled cloud subjected to solar and sky irradiation has been performed. The Radiation Element Method by Ray Emission Model (REM2) was used for numerical simulation. ...

Toru Nishikawa; Shigenao Maruyama; Seigo Sakai

2004-12-01T23:59:59.000Z

65

A Coupled AtmosphereOcean Radiative Transfer System Using the Analytic Four-Stream Approximation  

Science Conference Proceedings (OSTI)

A coupled atmosphereocean radiative transfer model based on the analytic four-stream approximation has been developed. It is shown that this radiation model is computationally efficient and at the same time can achieve acceptable accuracy for ...

Wei-Liang Lee; K. N. Liou

2007-10-01T23:59:59.000Z

66

A Two-Dimensional Radiation-Turbulence Climate Model. I: Sensitivity to Cirrus Radiative Properties  

Science Conference Proceedings (OSTI)

Based on the thermodynamic energy balance between radiation and vertical plus horizontal dynamic transports, a two-dimensional radiation-turbulence climate model is developed. This model consists of a broadband solar and IR radiation transfer ...

Szu-Cheng S. Ou; Kuo-Nan Liou

1984-08-01T23:59:59.000Z

67

A General Strategy for Physics-Based Model Validation Illustrated with Earthquake Phenomenology, Atmospheric Radiative Transfer, and Computational Fluid Dynamics  

E-Print Network (OSTI)

Validation is often defined as the process of determining the degree to which a model is an accurate representation of the real world from the perspective of its intended uses. Validation is crucial as industries and governments depend increasingly on predictions by computer models to justify their decisions. In this article, we survey the model validation literature and propose to formulate validation as an iterative construction process that mimics the process occurring implicitly in the minds of scientists. We thus offer a formal representation of the progressive build-up of trust in the model, and thereby replace incapacitating claims on the impossibility of validating a given model by an adaptive process of constructive approximation. This approach is better adapted to the fuzzy, coarse-grained nature of validation. Our procedure factors in the degree of redundancy versus novelty of the experiments used for validation as well as the degree to which the model predicts the observations. We illustrate the new methodology first with the maturation of Quantum Mechanics as the arguably best established physics theory and then with several concrete examples drawn from some of our primary scientific interests: a cellular automaton model for earthquakes, an anomalous diffusion model for solar radiation transport in the cloudy atmosphere, and a computational fluid dynamics code for the Richtmyer-Meshkov instability. This article is an augmented version of Sornette et al. [2007] that appeared in Proceedings of the National Academy of Sciences in 2007 (doi: 10.1073/pnas.0611677104), with an electronic supplement at URL http://www.pnas.org/cgi/content/full/0611677104/DC1. Sornette et al. [2007] is also available in preprint form at physics/0511219.

Didier Sornette; Anthony B. Davis; James R. Kamm; Kayo Ide

2007-10-01T23:59:59.000Z

68

Four-Stream Isosector Approximation for Solar Radiative Transfer  

Science Conference Proceedings (OSTI)

For radiative transfer in a thin atmosphere, an analytical four-stream isosector approximation for solar radiative transfer is presented. This approximation method is based on the assumption of four spherical sectors of isotropic intensities. ...

J. Li; J. S. Dobbie

1998-02-01T23:59:59.000Z

69

Multimode Radiative Transfer in Finite Optical Media. I: Fundamentals  

Science Conference Proceedings (OSTI)

In this paper we develop a new method for solving the transfer of radiation within a laterally finite optical medium. A new radiative transfer equation, based on a multimode approach, is developed which includes the explicit effects of the sides ...

Rudolph W. Preisendorfer; Graeme L. Stephens

1984-03-01T23:59:59.000Z

70

Solar radiation model validation  

Science Conference Proceedings (OSTI)

Several mathematical models have been developed within the past few years which estimate the solar radiation from other weather variables. Some of these models have been used to generate data bases which are extensively used in the design and analysis of solar system. Three of these solar radiation models have been used in developing the Augmented SOLMET Solar Data Tapes for the 26 SOLMET sites and the 222 ERSATZ Solar Data Tapes. One of the models, a theoretical one, predicts the solar noon radiation for clear sky conditions from the optical air mass, precipitable water vapor and turbidity variables. A second model, an empirical one, predicts the hourly total horizontal radiation from meteorological variables. And, a third model, also an empirical one, predicts the hourly direct normal radiation from the hourly total horizontal radiation. A study of the accuracy of these three solar radiation models is reported here. To assess the accuracy of these models, data were obtained from several US National Weather Service Stations and other sources, used the models to estimate the solar-radiation, and then compared the modeled radiation values with observed radiation values. The results of these comparisons and conclusions regarding the accuracy of the models are presented.

Hall, I.J.; Prairie, R.R.; Anderson, H.E.; Boes, E.C.

1980-10-01T23:59:59.000Z

71

Boundary conditions for NLTE polarized radiative transfer with incident radiation  

E-Print Network (OSTI)

Polarized NLTE radiative transfer in the presence of scattering in spectral lines and/or in continua may be cast in a so-called reduced form for six reduced components of the radiation field. In this formalism the six components of the reduced source function are angle-independent quantities. It thus reduces drastically the storage requirement of numerical codes. This approach encounters a fundamental problem when the medium is illuminated by a polarized incident radiation, because there is a priori no way of relating the known (and measurable) Stokes parameters of the incident radiation to boundary conditions for the reduced equations. The origin of this problem is that there is no unique way of deriving the radiation reduced components from its Stokes parameters (only the inverse operation is clearly defined). The method proposed here aims at enabling to work with arbitrary incident radiation field (polarized or unpolarized). In previous works an ad-hoc treatment of the boundary conditions, applying to case...

Faurobert, Marianne; Atanackovic, Olga

2013-01-01T23:59:59.000Z

72

Prospects for Money Transfer Models  

E-Print Network (OSTI)

Recently, in order to explore the mechanism behind wealth or income distribution, several models have been proposed by applying principles of statistical mechanics. These models share some characteristics, such as consisting of a group of individual agents, a pile of money and a specific trading rule. Whatever the trading rule is, the most noteworthy fact is that money is always transferred from one agent to another in the transferring process. So we call them money transfer models. Besides explaining income and wealth distributions, money transfer models can also be applied to other disciplines. In this paper we summarize these areas as statistical distribution, economic mobility, transfer rate and money creation. First, money distribution (or income distribution) can be exhibited by recording the money stock (flow). Second, the economic mobility can be shown by tracing the change in wealth or income over time for each agent. Third, the transfer rate of money and its determinants can be analyzed by tracing t...

Wang, Y; Xi, N; Wang, Yougui; Ding, Ning; Xi, Ning

2005-01-01T23:59:59.000Z

73

Modeling of Heat Transfer in Rooms in the Modelica Buildings Library  

E-Print Network (OSTI)

for convective and radiative heat transfer yielded a twofoldModeling of Heat Transfer in Rooms in the Modelica of California. MODELING OF HEAT TRANSFER IN ROOMS IN THE

Wetter, Michael

2013-01-01T23:59:59.000Z

74

Posters The Effects of Radiative Transfer  

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

Posters The Effects of Radiative Transfer on Low-Level Cyclogenesis M. J. Leach and S. Raman Department of Marine, Earth and Atmospheric Sciences North Carolina State University Raleigh, North Carolina Introduction Many investigators have documented the role that thermodynamic forcing due to radiative flux divergence plays in the enhancement or generation of circulation. Most of these studies involve large-scale systems (e.g., Slingo et al. 1988), small-scale systems such as thunderstorms (Chen and Cotton 1988), and squall lines (Chin, submitted). The generation of circulation on large scales results from the creation of divergence in the upper troposphere and the maintenance of low-level potentially unstable air, and the maintenance of baroclinicity throughout

75

Entrainment-Mixing and Radiative Transfer Simulation in Boundary Layer Clouds  

Science Conference Proceedings (OSTI)

In general circulation models, clouds are parameterized and radiative transfer calculations are performed using the plane-parallel approximation over the cloudy fraction of each model grid. The albedo bias resulting from the plane-parallel ...

Frdrick Chosson; Jean-Louis Brenguier; Lothar Schller

2007-07-01T23:59:59.000Z

76

Solar radiation modelling  

Science Conference Proceedings (OSTI)

The Sun is the main energy source of the life on the Earth. Thus, solar radiation energy data and models are important for many areas of research and applications. Many parameters influence the amount of solar energy at a particular standing point of ... Keywords: Digital elevation model, Energy of quasiglobal radiation, Meteorology, Shadows, Virtual Sun motion

Klemen Zakek; Toma Podobnikar; Kritof Otir

2005-03-01T23:59:59.000Z

77

Radiative Transfer Simulations Using Mesoscale Cloud Model Outputs: Comparisons with Passive Microwave and Infrared Satellite Observations for Midlatitudes  

Science Conference Proceedings (OSTI)

Real midlatitude meteorological cases are simulated over western Europe with the cloud mesoscale model Mso-NH, and the outputs are used to calculate brightness temperatures at microwave frequencies with the Atmospheric Transmission at Microwave (...

Ingo Meirold-Mautner; Catherine Prigent; Eric Defer; Juan R. Pardo; Jean-Pierre Chaboureau; Jean-Pierre Pinty; Mario Mech; Susanne Crewell

2007-05-01T23:59:59.000Z

78

Prospects for Money Transfer Models  

E-Print Network (OSTI)

Summary. Recently, in order to explore the mechanism behind wealth or income distribution, several models have been proposed by applying principles of statistical mechanics. These models share some characteristics, such as consisting of a group of individual agents, a pile of money and a specific trading rule. Whatever the trading rule is, the most noteworthy fact is that money is always transferred from one agent to another in the transferring process. So we call them money transfer models. Besides explaining income and wealth distributions, money transfer models can also be applied to other disciplines. In this paper we summarize these areas as statistical distribution, economic mobility, transfer rate and money creation. First, money distribution (or income distribution) can be exhibited by recording the money stock (flow). Second, the economic mobility can be shown by tracing the change in wealth or income over time for each agent. Third, the transfer rate of money and its determinants can be analyzed by tracing the transferring process of each one unit of money. Finally, money creation process can also be investigated by permitting agents go into debts. Some future extensions to these models are anticipated to be structural improvement and generalized mathematical analysis.

Yougui Wang; Ning Ding; Ning Xi

2005-01-01T23:59:59.000Z

79

Parameterization and Analysis of 3-D Solar Radiative Transfer in Clouds: Final Report  

Science Conference Proceedings (OSTI)

This document reports on the research that we have done over the course of our two-year project. The report also covers the research done on this project during a 1 year no-cost extension of the grant. Our work has had two main, inter-related thrusts: The first thrust was to characterize the response of stratocumulus cloud structure and dynamics to systematic changes in cloud infrared radiative cooling and solar heating using one-dimensional radiative transfer models. The second was to couple a three-dimensional (3-D) solar radiative transfer model to the Large Eddy Simulation (LES) model that we use to simulate stratocumulus. The purpose of the studies with 3-D radiative transfer was to examine the possible influences of 3-D photon transport on the structure, evolution, and radiative properties of stratocumulus. While 3-D radiative transport has been examined in static cloud environments, few studies have attempted to examine whether the 3-D nature of radiative absorption and emission influence the structure and evolution of stratocumulus. We undertook this dual approach because only a small number of LES simulations with the 3-D radiative transfer model are possible due to the high computational costs. Consequently, LES simulations with a 1-D radiative transfer solver were used in order to examine the portions of stratocumulus parameter space that may be most sensitive to perturbations in the radiative fields. The goal was then to explore these sensitive regions with LES using full 3-D radiative transfer. Our overall goal was to discover whether 3-D radiative processes alter cloud structure and evolution, and whether this may have any indirect implications for cloud radiative properties. In addition, we collaborated with Dr. Tamas Varni, providing model output fields for his attempt at parameterizing 3-D radiative effects for cloud models.

Jerry Y. Harrington

2012-09-21T23:59:59.000Z

80

Semi-implicit time integration for PN thermal radiative transfer  

Science Conference Proceedings (OSTI)

Implicit time integration involving the solution of large systems of equations is the current paradigm for time-dependent radiative transfer. In this paper we present a semi-implicit, linear discontinuous Galerkin method for the spherical harmonics (P"N) ... Keywords: Asymptotic diffusion limit, Discontinuous Galerkin, PN approximation, Thermal radiative transfer

Ryan G. McClarren; Thomas M. Evans; Robert B. Lowrie; Jeffery D. Densmore

2008-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Multiresolution Analysis of Radiative Transfer through Inhomogeneous Media. Part II: Validation and New Insights  

Science Conference Proceedings (OSTI)

The multiresolution radiative transfer equations of Part I of this paper are solved numerically for the case of inhomogeneous model clouds using Meyers basis functions. After analyzing the properties of Meyers connection coefficients and ...

Nicolas Ferlay; Harumi Isaka; Philip Gabriel; Albert Benassi

2006-04-01T23:59:59.000Z

82

Radiative Transfer on a Linear Lattice: Application to Anisotropic Ice Crystal Clouds  

Science Conference Proceedings (OSTI)

The problem of radiative transfer in a horizontally infinite cloud layer possessing anisotropy with respect to volume extinction and other single-scattering properties was solved using the method of discrete space theory. The model was applied to ...

Graeme L. Stephens

1980-09-01T23:59:59.000Z

83

The Spherical Harmonics Discrete Ordinate Method for Three-Dimensional Atmospheric Radiative Transfer  

Science Conference Proceedings (OSTI)

A new algorithm for modeling radiative transfer in inhomogeneous three-dimensional media is described. The spherical harmonics discrete ordinate method uses a spherical harmonic angular representation to reduce memory use and time computing the ...

K. Franklin Evans

1998-02-01T23:59:59.000Z

84

Aircraft Observations of the Vertical Structure of Stratiform Precipitation Relevant to Microwave Radiative Transfer  

Science Conference Proceedings (OSTI)

The retrieval of rainfall intensity over the oceans from passive microwave observations is based on a radiative transfer model. Direct rainfall observations of oceanic rainfall are virtually nonexistent making validation of the retrievals ...

A. T. C. Chang; A. Barnes; M. Glass; R. Kakar; T. T. Wilheit

1993-06-01T23:59:59.000Z

85

Present and Future Computing Requirements Radiative Transfer...  

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

radiative shock (e.g., ensman 1994) gas temperature radiation temperature Local Thermodynamic Equilibrium (LTE) non-equilibrium (NLTE) CaII microphysics 1GB atomic data...

86

Application of Improved Radiation Modeling to General Circulation Models  

SciTech Connect

This research has accomplished its primary objectives of developing accurate and efficient radiation codes, validating them with measurements and higher resolution models, and providing these advancements to the global modeling community to enhance the treatment of cloud and radiative processes in weather and climate prediction models. A critical component of this research has been the development of the longwave and shortwave broadband radiative transfer code for general circulation model (GCM) applications, RRTMG, which is based on the single-column reference code, RRTM, also developed at AER. RRTMG is a rigorously tested radiation model that retains a considerable level of accuracy relative to higher resolution models and measurements despite the performance enhancements that have made it possible to apply this radiation code successfully to global dynamical models. This model includes the radiative effects of all significant atmospheric gases, and it treats the absorption and scattering from liquid and ice clouds and aerosols. RRTMG also includes a statistical technique for representing small-scale cloud variability, such as cloud fraction and the vertical overlap of clouds, which has been shown to improve cloud radiative forcing in global models. This development approach has provided a direct link from observations to the enhanced radiative transfer provided by RRTMG for application to GCMs. Recent comparison of existing climate model radiation codes with high resolution models has documented the improved radiative forcing capability provided by RRTMG, especially at the surface, relative to other GCM radiation models. Due to its high accuracy, its connection to observations, and its computational efficiency, RRTMG has been implemented operationally in many national and international dynamical models to provide validated radiative transfer for improving weather forecasts and enhancing the prediction of global climate change.

Michael J Iacono

2011-04-07T23:59:59.000Z

87

Near-field radiative heat transfer for structured surfaces  

E-Print Network (OSTI)

We apply an analytical approach for determining the near-field radiative heat transfer between a metallic nanosphere and a planar semi-infinite medium with some given surface structure. This approach is based on a perturbative expansion, and evaluated to first order in the surface profile. With the help of numerical results obtained for some simple model geometries we discuss typical signatures that should be obtainable with a near-field scanning thermal microscope operated in either constant-height or constant-distance mode.

Svend-Age Biehs; Oliver Huth; Felix Rting

2011-03-15T23:59:59.000Z

88

Influence of Infrared Radiation on Attic Heat Transfer  

E-Print Network (OSTI)

An experimental study concerned with different modes of heal transfer in fibrous and cellulose insulating material is presented. A series of experiments were conducted using an attic simulator to determine the effects of ventilation on attic heat transfer, and the effect of infrared radiation on the thermal conductivity of the insulation system and on attic heat transfer. All the tests were performed at steady state conditions by controlling the roof deck temperature. Calculations are performed for insulation thicknesses between 1 inch (2.54cm) and 6.0 inches (15.24cm) and roof deck temperatures between 145F (62.78C) and 100F (36.78C). The temperature profiles within the insulation were measured by placing thermocouples at various levels within the insulation. The profiles for the cellulose insulation are linear. The profiles within the glass fiber insulation are non-linear due to the effect of infrared radiation. Also heat fluxes were measured through different insulation thicknesses and for different roof temperatures. It was found that a radiant barrier such as aluminum foil can reduce the heat flux significantly. Experimental results were compared to a Three-Region approximate solution developed at Oak Ridge National Laboratories (ORNL). The model was in good agreement with experimental results.

Katipamula, S.; Turner, W. D.; Murphy, W. E.; O'Neal, D. L.

1985-01-01T23:59:59.000Z

89

Solar Radiative Transfer for Wind-Sheared Cumulus Cloud Fields  

Science Conference Proceedings (OSTI)

The Monte Carlo method of photon transport was used to simulate solar radiative transfer for cumulus-like cloud forms (and cloud fields) possessing structural characteristics similar to those induced by wind shear. Using regular infinite arrays ...

Howard W. Barker

1994-05-01T23:59:59.000Z

90

Multiple Scattering Parameterization in Thermal Infrared Radiative Transfer  

Science Conference Proceedings (OSTI)

A systematic formulation of various radiative transfer parameterizations is presented, including the absorption approximation (AA), ?-two-stream approximation (D2S), ?-four-stream approximation (D4S), and ?-two- and four-stream combination ...

Qiang Fu; K. N. Liou; M. C. Cribb; T. P. Charlock; A. Grossman

1997-12-01T23:59:59.000Z

91

Radiative Transfer in Cloud Fields with Random Geometry  

Science Conference Proceedings (OSTI)

Numerical results are given to estimate the importance of effects associated with the stochastic geometry of cloud fields. These results show the important of treating radiative transfer in broken clouds as a statistical problem. In the case of ...

Vladimir E. Zuev; Georgii A. Titov

1995-01-01T23:59:59.000Z

92

The Scaling Group of the Radiative Transfer Equation  

Science Conference Proceedings (OSTI)

We show that the equation of radiative transfer is invariant under a group of simultaneous transformations of the scale (i.e., the optical thickness) and the phase function. In this way, we provide a unified explanation of various empirical ...

Bruce H. J. McKellar; Michael A. Box

1981-05-01T23:59:59.000Z

93

Effective Diameter in Radiation Transfer: General Definition, Applications, and Limitations  

Science Conference Proceedings (OSTI)

Although the use of an effective radius for radiation transfer calculations in water clouds has been common for many years, the export of this concept to ice clouds has been fraught with uncertainty, due to the nonspherical shapes of ice ...

David L. Mitchell

2002-08-01T23:59:59.000Z

94

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

95

COMPARING THE EFFECT OF RADIATIVE TRANSFER SCHEMES ON CONVECTION SIMULATIONS  

Science Conference Proceedings (OSTI)

We examine the effect of different radiative transfer schemes on the properties of three-dimensional (3D) simulations of near-surface stellar convection in the superadiabatic layer, where energy transport transitions from fully convective to fully radiative. We employ two radiative transfer schemes that fundamentally differ in the way they cover the 3D domain. The first solver approximates domain coverage with moments, while the second solver samples the 3D domain with ray integrations. By comparing simulations that differ only in their respective radiative transfer methods, we are able to isolate the effect that radiative efficiency has on the structure of the superadiabatic layer. We find the simulations to be in good general agreement, but they show distinct differences in the thermal structure in the superadiabatic layer and atmosphere.

Tanner, Joel D.; Basu, Sarbani; Demarque, Pierre [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

2012-11-10T23:59:59.000Z

96

Enhanced radiative heat transfer between nanostructured gold plates  

E-Print Network (OSTI)

We compute the radiative heat transfer between nanostructured gold plates in the framework of the scattering theory. We predict an enhancement of the heat transfer as we increase the depth of the corrugations while keeping the distance of closest approach fixed. We interpret this effect in terms of the evolution of plasmonic and guided modes as a function of the grating's geometry.

R. Gurout; J. Lussange; F. S. S. Rosa; J. -P. Hugonin; D. A. R. Dalvit; J. -J. Greffet; A. Lambrecht; S. Reynaud

2012-03-07T23:59:59.000Z

97

A Comprehensive Radiation Scheme for Numerical Weather Prediction Models with Potential Applications in Climate Simulations  

Science Conference Proceedings (OSTI)

A comprehensive scheme for the parameterization of radiative transfer in numerical weather Prediction (NWP) models has been developed. The scheme is based on the solution of the ?-two-stream version of the radiative transfer equation ...

Bodo Ritter; Jean-Francois Geleyn

1992-02-01T23:59:59.000Z

98

Measurements and model calculations of radiative fluxes for the...  

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

are compared with calculations made with a state-of-the art radiative transfer model (Modtran). The model is driven by measurements that give an as accurate as possible...

99

Spectrally Invariant Approximation within Atmospheric Radiative Transfer  

Science Conference Proceedings (OSTI)

Certain algebraic combinations of single scattering albedo and solar radiation reflected from, or transmitted through, vegetation canopies do not vary with wavelength. These spectrally invariant relationships are the consequence of wavelength ...

A. Marshak; Y. Knyazikhin; J. C. Chiu; W. J. Wiscombe

2011-12-01T23:59:59.000Z

100

Handbook of radiative heat transfer in high-temperature gases  

Science Conference Proceedings (OSTI)

This work offers both an original method for calculating optical properties of low-temperature plasma at elevated densities ... and an effective new means for calculating radiative heat transfer in hot gases and plasma with arbitrary temperature and pressure distributions. These methods allow for automatic accounting of all details of the plasma spectrum, including the line structure. This volume contains radiant transfer in problems of heat transfer; integration over frequency; methods of partial characteristics; method of effective populations; calculation of partial characteristics; appendix: tabular data.

Soloukhin, R.I.; Golovnev, I.F.; Zamurayev, V.P.; Katsnelson, S.S.; Kovalskaya, G.A.; Sevastyanenko, V.G.; Soloukhin, R.I.

1987-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Test plan for validation of the radiative transfer equation.  

SciTech Connect

As the capabilities of numerical simulations increase, decision makers are increasingly relying upon simulations rather than experiments to assess risks across a wide variety of accident scenarios including fires. There are still, however, many aspects of fires that are either not well understood or are difficult to treat from first principles due to the computational expense. For a simulation to be truly predictive and to provide decision makers with information which can be reliably used for risk assessment the remaining physical processes must be studied and suitable models developed for the effects of the physics. A set of experiments are outlined in this report which will provide soot volume fraction/temperature data and heat flux (intensity) data for the validation of models for the radiative transfer equation. In addition, a complete set of boundary condition measurements will be taken to allow full fire predictions for validation of the entire fire model. The experiments will be performed with a lightly-sooting liquid hydrocarbon fuel fire in the fully turbulent scale range (2 m diameter).

Ricks, Allen Joseph; Grasser, Thomas W.; Kearney, Sean Patrick; Jernigan, Dann A.; Blanchat, Thomas K.

2010-09-01T23:59:59.000Z

102

Satellite-based remote sensing of cirrus clouds: hyperspectral radiative transfer modeling, analysis of uncertainties in in-situ cloud extinction measurements and intercomparison of cirrus retrievals from a-train instruments  

E-Print Network (OSTI)

This dissertation consists of three parts, each devoted to a particular issue of significant importance for satellite-based remote sensing of cirrus clouds. In the first part, we develop and present a fast infrared radiative transfer model on the basis of the adding-doubling principle. The model aims to facilitate the radiative transfer computations involved in hyperspectral remote sensing applications. The model is applicable to a variety of cloud conditions, including vertically inhomogeneous or multilayered clouds. It is shown that for hyperspectral applications the model is two order-of-magnitude faster than the well-known discrete ordinate transfer (DISORT) model, while maintains a similar accuracy. The second part is devoted to the investigation of uncertainties in the FSSP (Forward Scattering Spectrometer Probe) measurement of cloud extinction by small ice particles. First, the single-scattering properties of small ice particles in cirrus clouds are derived and compared to those of equivalent spheres according to various definitions. It is found that, although small ice particles in cirrus clouds are often quasi-spherical, their scattering phase functions and asymmetry factors are significant different from those of ice spheres. Such differences may lead to substantial underestimation of cloud extinction in FSSP measurement, if small ice particles are assumed to be spheres. In the third part, we present a comparison of cirrus cloud optical thickness retrievals from two important instruments, MODIS (Moderate Resolution Imaging Spectrometer) and POLDER (Polarization and Directionality of Earths Reflection), on board NASAs A-train satellite constellation. The comparison reveals a large difference. Several possible reasons are discussed. It is found that much of the difference is attributable to the difference between the MODIS and POLDER retrieval algorithm in the assumption of cirrus cloud bulk scattering properties. Potential implications of the difference for climate studies are investigated. An important finding is that the use of an unrealistic cirrus bulk scattering model might introduce artificial seasonal variation of cirrus optical thickness and shortwave radiative forcing into the retrieval.

Zhang, Zhibo

2008-08-01T23:59:59.000Z

103

Choosing an Approximation to the Equation of Radiative Transfer  

Science Conference Proceedings (OSTI)

We examine the accuracy of the PL, approximation to the equation of radiative transfer in the presence of scattering/absorbing clouds of various optical thicknesses. We find that very accurate net fluxes can be obtained with the P1, (two-stream) ...

James A. Fillmore; Alan H. Karp

1980-08-01T23:59:59.000Z

104

A mesoscopic description of radiative heat transfer at the nanoscale  

E-Print Network (OSTI)

We present a formulation of the nanoscale radiative heat transfer (RHT) using concepts of mesoscopic physics. We introduce the analog of the Sharvin conductance using the quantum of thermal conductance. The formalism provides a convenient framework to analyse the physics of RHT at the nanoscale. Finally, we propose a RHT experiment in the regime of quantized conductance.

Svend-Age Biehs; Emmanuel Rousseau; Jean-Jacques Greffet

2011-03-11T23:59:59.000Z

105

Statistical Description of Radiation Transfer in Clouds  

Science Conference Proceedings (OSTI)

The statistical characteristics of simulated cloud fields constructed based on Poisson point fluxes are studied. The input parameters of mathematical models of cloudiness include the cloud fraction and the mean horizontal size of clouds ...

Georgi A. Titov

1990-01-01T23:59:59.000Z

106

Application of the adjoint method in atmospheric radiative transfer calculations  

DOE Green Energy (OSTI)

The transfer of solar radiation through a standard mid-latitude summer atmosphere including different amounts of aerosols (from clear to hazy) has been computed. The discrete-ordinates (S/sub N/) method, which has been developed to a high degree of computational efficiency and accuracy primarily for nuclear radiation shielding applications, is employed in a forward as well as adjoint mode. In the adjoint mode the result of a transfer calculation is an importance function (adjoint intensity) which allows the calculation of transmitted fluxes, or other radiative responses, for any arbitrary source distribution. The theory of the adjoint method is outlined in detail and physical interpretations are developed for the adjoint intensity. If, for example, the downward directed solar flux at ground level, F/sub lambda/ (z = 0), is desired for N different solar zenith angles, a regular (forward) radiative transfer calculation must be repeated for each solar zenith angle. In contrast, only 1 adjoint transfer calculation gives F/sub lambda/ (z = 0) for all solar zenith angles in a hazy aerosol atmosphere, for 1 wavelength interval, in 2.3 seconds on a CDC-7600 computer. A total of 155 altitude zones were employed between 0 and 70 km, and the convergence criterion for the ratio of fluxes from successive iterations was set at 2 x 10/sup -3/. Our results demonstrate not only the applicability of the highly efficient modern S/sub N/ codes, but indicate also conceptual and computational advantages when the adjoint formulation of the radiative transfer equation is used.

Gerstl, S.A.W.

1979-01-01T23:59:59.000Z

107

Microweve Radiative Transfer through Clouds Composed of Realistically Shaped Ice Crystals. Part II. Remote Sensing of Ice Clouds  

Science Conference Proceedings (OSTI)

This paper presents the results of polarized microwave radiative transfer modeling of cirrus clouds containing five different particle shoes and 18 Gamma size distributions. Upwelling brightness temperatures for tropical and midlatitude winter ...

K. Franklin Evans; Graeme L. Stephens

1995-06-01T23:59:59.000Z

108

The Full-Spectrum Correlated-k Method for Longwave Atmospheric Radiative Transfer Using an Effective Planck Function  

Science Conference Proceedings (OSTI)

The correlated-k-distribution (CKD) method is widely used in the radiative transfer schemes of atmospheric models; it involves dividing the spectrum into a number of bands and then reordering the gaseous absorption coefficients within each one. ...

Robin J. Hogan

2010-06-01T23:59:59.000Z

109

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

110

Incorporating the Effects of 3D Radiative Transfer in the Presence of Clouds into Two-Stream Multilayer Radiation Schemes  

Science Conference Proceedings (OSTI)

This paper presents a new method for representing the important effects of horizontal radiation transport through cloud sides in two-stream radiation schemes. Ordinarily, the radiative transfer equations are discretized separately for the clear ...

Robin J. Hogan; Jonathan K. P. Shonk

2013-02-01T23:59:59.000Z

111

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

112

Application of Stochastic Radiative Transfer Theory to the ARM Cloud-Radiative Parameterization Problem  

Science Conference Proceedings (OSTI)

This project had two primary goals: (1) development of stochastic radiative transfer as a parameterization that could be employed in an AGCM environment, and (2) exploration of the stochastic approach as a means for representing shortwave radiative transfer through mixed-phase layer clouds. To achieve these goals, climatology of cloud properties was developed at the ARM CART sites, an analysis of the performance of the stochastic approach was performed, a simple stochastic cloud-radiation parameterization for an AGCM was developed and tested, a statistical description of Arctic mixed phase clouds was developed and the appropriateness of stochastic approach for representing radiative transfer through mixed-phase clouds was assessed. Significant progress has been made in all of these areas and is detailed in the final report.

Dana E. Veron

2012-04-09T23:59:59.000Z

113

The Radiative Transfer Of CH{sub 4}-N{sub 2} Plasma Arc  

Science Conference Proceedings (OSTI)

Any physical modelling of a circuit-breaker arc therefore requires an understanding of the radiated energy which is taken into account in the form of a net coefficient. The evaluation of the net emission coefficient is performed by the knowledge of the chemical plasma composition and the resolution of the radiative transfer equation. In this paper, the total radiation which escapes from a CH{sub 4}-N{sub 2} plasma is calculated in the temperature range between 5000 and 30000K on the assumption of a local thermodynamic equilibrium and we have studied the nitrogen effect in the hydrocarbon plasmas.

Benallal, R. [Theoretical physics Laboratory, Physics Department of University Aboubekr Belkaied Tlemcen 13000 (Algeria); Liani, B. [Science Faculty, Hassiba Benbouali University, Chlef 02000 (Algeria)

2008-09-23T23:59:59.000Z

114

Documentation for the intergalactic radiative transfer code IGMtransfer  

E-Print Network (OSTI)

This document describes the publically available numerical code "IGMtransfer", capable of performing intergalactic radiative transfer (RT) of light in the vicinity of the Lyman alpha (Lya) line. Calculating the RT in a (possibly adaptively refined) grid of cells resulting from a cosmological simulation, the code returns 1) a "transmission function", showing how the intergalactic medium (IGM) affects the Lya line at a given redshift, and 2) the "average transmission" of the IGM, making it useful for studying the results of reionization simulations.

Laursen, Peter

2010-01-01T23:59:59.000Z

115

MODELING HEAT TRANSFER IN SPENT FUEL TRANSFER CASK NEUTRON SHIELDS A CHALLENGING PROBLEM IN NATURAL CONVECTION  

SciTech Connect

In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 10-15 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper proposes that there may be reliable CFD approaches to the transfer cask problem, specifically coupled steady-state solvers or unsteady simulations; however, both of these solutions take significant computational effort. Segregated (uncoupled) steady state solvers that were tested did not accurately capture the flow field and heat transfer distribution in this application. Mesh resolution, turbulence modeling, and the tradeoff between steady state and transient solutions are addressed. Because of the critical nature of this application, the need for new experiments at representative scales is clearly demonstrated.

Fort, James A.; Cuta, Judith M.; Bajwa, C.; Baglietto, E.

2010-07-18T23:59:59.000Z

116

Numerical Modeling of Heat Pipe Radiator and Fin Size Optimization for Low and No Gravity Environments.  

E-Print Network (OSTI)

??A heat-pipe radiator element has been designed and modeled to study the efficiency of heat transfer for low and no gravity environments, like in lunar (more)

Bieger, Virginia Ruth

2013-01-01T23:59:59.000Z

117

Radiation Environment Assimilation Model (DREAM).  

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

DREAM tool increases space weather DREAM tool increases space weather predictions April 13, 2012 Predicting space weather improved by new DREAM modeling tool Earth's radiation belts can now be studied with a new modeling tool called Dynamic Radiation Environment Assimilation Model (DREAM). Researchers in LANL's Space Science and Applications (ISR-1) group are developing DREAM and described its current capabilities and applications in an article published in Space Weather, a journal of the American Geophysical Union. - 2 - Space environment and its hazards The space environment poses a number of radiation hazards to space systems and their occupants. Relativistic electrons, the dominant source of the radiation dose to spacecraft traveling in the outer radiation belts (3-7 Earth radii), have an electron flux

118

A model for laboratory tech transfer investment  

Science Conference Proceedings (OSTI)

A simple model has been developed to address a pragmatic question: What fraction of its research and development budget should a national laboratory devote to enhancing technology in the private sector? In dealing with lab-wide budgets in an aggregate sense, the model uses three parameters - fraction of lab R&D transferable to industry, transfer efficiency and payback to laboratory missions - to partition fixed R&D resources between technology transfer and core missions. It is a steady-state model in that the transfer process is assumed to work in equilibrium with technology generation. The results presented should be of use to those engaged in managing and overseeing federal laboratory technology transfer activities.

Otey, G.R.; Carson, C.C.; Bomber, T.M.; Rogers, J.D.

1994-06-01T23:59:59.000Z

119

Spectral Absorption of Solar Radiation in Cloudy Atmospheres: A 20 cm?1 Model  

Science Conference Proceedings (OSTI)

The spectral of solar radiation in typical water clouds is determined using a radiative transfer model based on LOWTRAN transmission functions at a 20 cm?1 resolution and Monte Carlo simulations of photon pathlength distributions. Relative ...

Roger Davies; William L. Ridgway; Kyung-Eak Kim

1984-07-01T23:59:59.000Z

120

The Effect of Tropospheric Aerosols on the Earth's Radiation Budget: A Parameterization for Climate Models  

Science Conference Proceedings (OSTI)

Guided by the results of doubling-adding solutions to the equation of radiative transfer, we develop a simple technique for incorporating in climate models the effect of the background tropospheric aerosol on solar radiation. Because the ...

James A. Coakley Jr.; Robert D. Cess; Franz B. Yurevich

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Modeling radiation characteristics of semitransparent media containing bubbles or particles.  

E-Print Network (OSTI)

and heat, mass, and radiation transfer, Journal of Non-Sacadura, J. F. , Thermal radiation properties of dispersedG. , and Viskanta, R. , Radiation characteristics of glass

Randrianalisoa, Jaona; Baillis, Dominique; Pilon, Laurent

2006-01-01T23:59:59.000Z

122

A Model for Particle Microphysics, Turbulent Mixing, and Radiative Transfer in the Stratocumulus-Topped Marine Boundary Layer and Comparisons with Measurements  

Science Conference Proceedings (OSTI)

A detailed 1D model of the stratocumulus-topped marine boundary layer is described. The model has three coupled components: a microphysics module that resolves the size distributions of aerosols and cloud droplets, a turbulence module that treats ...

Andrew S. Ackerman; Peter V. Hobbs; Owen B. Toon

1995-04-01T23:59:59.000Z

123

An Estimation of the Bulk Transfer Coefficients for a Bare Soil Surface Using a Linear Model  

Science Conference Proceedings (OSTI)

A linear heat budget model is developed to estimate the daytime means of the bulk transfer coefficients for heat and evaporation efficiency using the daily variation of observational data. The daily variation of shortwave radiation, ground-level ...

Dai Matsushima; Junsei Kondo

1995-04-01T23:59:59.000Z

124

CHAPARRAL: A library for solving large enclosure radiation heat transfer problems  

SciTech Connect

Large, three-dimensional enclosure radiation beat transfer problems place a heavy demand on computing resources such as computational cycles, memory requirements, disk I/O, and disk space usage. This is primarily due to the computational and memory requirements associated with the view factor calculation and subsequent access of the view factor matrix during solution of the radiosity matrix equation. This is a fundamental problem that constrains Sandia`s current modeling capabilities. Reducing the computational and memory requirements for calculating and manipulating view factors would enable an analyst to increase the level of detail at which a body could be modeled and would have a major impact on many programs at Sandia such as weapon and transportation safety programs, component survivability programs, energy programs, and material processing programs. CHAPARRAL is a library package written to address these problems and is specifically tailored towards the efficient solution of extremely large three-dimensional enclosure radiation heat transfer problems.

Glass, M.W.

1995-08-01T23:59:59.000Z

125

Thermal correction to the Casimir force, radiative heat transfer, and an experiment  

E-Print Network (OSTI)

The low-temperature asymptotic expressions for the Casimir interaction between two real metals described by Leontovich surface impedance are obtained in the framework of thermal quantum field theory. It is shown that the Casimir entropy computed using the impedance of infrared optics vanishes in the limit of zero temperature. By contrast, the Casimir entropy computed using the impedance of the Drude model attains at zero temperature a positive value which depends on the parameters of a system, i.e., the Nernst heat theorem is violated. Thus, the impedance of infrared optics withstands the thermodynamic test, whereas the impedance of the Drude model does not. We also perform a phenomenological analysis of the thermal Casimir force and of the radiative heat transfer through a vacuum gap between real metal plates. The characterization of a metal by means of the Leontovich impedance of the Drude model is shown to be inconsistent with experiment at separations of a few hundred nanometers. A modification of the impedance of infrared optics is suggested taking into account relaxation processes. The power of radiative heat transfer predicted from this impedance is several times less than previous predictions due to different contributions from the transverse electric evanescent waves. The physical meaning of low frequencies in the Lifshitz formula is discussed. It is concluded that new measurements of radiative heat transfer are required to find out the adequate description of a metal in the theory of electromagnetic fluctuations.

V. B. Bezerra; G. Bimonte; G. L. Klimchitskaya; V. M. Mostepanenko; C. Romero

2007-08-18T23:59:59.000Z

126

The Economic Mobility in Money Transfer Models  

E-Print Network (OSTI)

In this paper, we investigate the economic mobility in some money transfer models which have been applied into the research on monetary distribution. We demonstrate the mobility by recording the agents' ranks time series and observing the volatility. We also compare the mobility quantitatively by employing an index, "the per capita aggregate change in log-income", raised by economists. Like the shape of distribution, the character of mobility is also decided by the trading rule in these transfer models. It is worth noting that even though different models have the same type of distribution, their mobility characters may be quite different.

Ding, N; Wang, Y; Ding, Ning; Xi, Ning; Wang, Yougui

2005-01-01T23:59:59.000Z

127

Development of a Second-Generation Regional Climate Model (RegCM2). Part I: Boundary-Layer and Radiative Transfer Processes  

Science Conference Proceedings (OSTI)

During the last few years the development of a second-generation regional climate modeling system (RegCM2) has been completed at the National Center for Atmospheric Research (NCAR). Based upon the National Center for Atmospheric Research-...

Filippo Giorgi; Maria Rosaria Marinucci; Gary T. Bates

1993-10-01T23:59:59.000Z

128

COLLAPSE OF MOLECULAR CLOUD CORES WITH RADIATION TRANSFER: FORMATION OF MASSIVE STARS BY ACCRETION  

Science Conference Proceedings (OSTI)

Most early radiative transfer calculations of protostellar collapse have suggested an upper limit of approx40 M{sub sun} for the final stellar mass before radiation pressure can exceed the star's gravitational pull and halt the accretion. Here we perform further collapse calculations, using frequency-dependent radiation transfer coupled to a frequency-dependent dust model that includes amorphous carbon particles, silicates, and ice-coated silicates. The models start from pressure-bounded, logatropic spheres of mass between 5 M{sub sun} and 150 M{sub sun} with an initial nonsingular density profile. We find that in a logatrope the infall is never reversed by the radiative forces on the dust and that stars with masses approx>100 M{sub sun} may form by continued accretion. Compared to previous models that start the collapse with a rho propor to r{sup -2} density configuration, our calculations result in higher accretion times and lower average accretion rates with peak values of approx5.8 x 10{sup -5} M{sub sun} yr{sup -1}. The radii and bolometric luminosities of the produced massive stars (approx>90 M{sub sun}) are in good agreement with the figures reported for detected stars with initial masses in excess of 100 M{sub sun}. The spectral energy distribution from the stellar photosphere reproduces the observed fluxes for hot molecular cores with peaks of emission from mid- to near-infrared.

Sigalotti, Leonardo Di G.; Daza-Montero, Judith [Centro de Fisica, Instituto Venezolano de Investigaciones CientIficas, IVIC, Apartado 21827, Caracas 1020A (Venezuela, Bolivarian Republic of); De Felice, Fernando [Dipartimento di Fisica 'G. Galilei', Universita di Padova, Via Marzolo 8 35131 Padova (Italy)

2009-12-20T23:59:59.000Z

129

Computational study of atmospheric transfer radiation on an equatorial tropical desert (La Tatacoa, Colombia)  

E-Print Network (OSTI)

Radiative transfer models explain and predict interaction between solar radiation and the different elements present in the atmosphere, which are responsible for energy attenuation. In Colombia there have been neither measurements nor studies of atmospheric components such as gases and aerosols that can cause turbidity and pollution. Therefore satellite images cannot be corrected radiometrically in a proper way. When a suitable atmospheric correction is carried out, loss of information is avoided, which may be useful for discriminating image land cover. In this work a computational model was used to find radiative atmospheric attenuation (300 1000nm wavelength region) on an equatorial tropical desert (La Tatacoa, Colombia) in order to conduct an adequate atmospheric correction.

Delgado-Correal, Camilo; Castao, Gabriel

2012-01-01T23:59:59.000Z

130

Implied Dynamic Feedback of 3D IR Radiative Transfer on Simulated...  

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

of 3D IR Radiative Transfer on Simulated Cloud Fields D. B. Mechem and Y. L. Kogan Cooperative Institute for Mesoscale Meteorological Studies University of Oklahoma Norman,...

131

Radiative Transfer in Cirrus Clouds. Part IV: On Cloud Geometry, Inhomogeneity, and Absorption  

Science Conference Proceedings (OSTI)

The effects of cloud geometry and inhomogeneity on the radiative properties of cirrus clouds are investigated by using the successive orders of scattering (SOS) approach for radiative transfer. This approach is an integral solution method that em ...

K. N. Liou; N. Rao

1996-11-01T23:59:59.000Z

132

Radiative Transfer through Arbitrarily Shaped Optical Media. Part I: A General Method of Solution  

Science Conference Proceedings (OSTI)

A general transform method is presented for studying problems of radiative transfer through absorbing, emitting and anisotropically scattering media exposed to arbitrary radiation conditions on its boundaries. The method permits quite arbitrary ...

Graeme L. Stephens

1988-06-01T23:59:59.000Z

133

Finite-volume model for chemical vapor infiltration incorporating radiant heat transfer. Interim report  

SciTech Connect

Most finite-volume thermal models account for the diffusion and convection of heat and may include volume heating. However, for certain simulation geometries, a large percentage of heat flux is due to thermal radiation. In this paper a finite-volume computational procedure for the simulation of heat transfer by conduction, convection and radiation in three dimensional complex enclosures is developed. The radiant heat transfer is included as a source term in each volume element which is derived by Monte Carlo ray tracing from all possible radiating and absorbing faces. The importance of radiative heat transfer is illustrated in the modeling of chemical vapor infiltration (CVI) of tubes. The temperature profile through the tube preform matches experimental measurements only when radiation is included. An alternative, empirical approach using an {open_quotes}effective{close_quotes} thermal conductivity for the gas space can match the initial temperature profile but does not match temperature changes that occur during preform densification.

Smith, A.W.; Starr, T.L. [Georgia Institute of Technology, Atlanta, GA (United States). School of Materials Science and Engineering

1995-05-01T23:59:59.000Z

134

TAU: A 1D radiative transfer code for transmission spectroscopy of extrasolar planet atmospheres  

E-Print Network (OSTI)

The TAU code is a 1D line-by-line radiative transfer code, which is generally applicable for modelling transmission spectra of close-in extrasolar planets. The inputs are the assumed pressure-temperature profile of the planetary atmosphere, the continuum absorption coefficients and the absorption cross-sections for the trace molecular absorbers present in the model, as well as the fundamental system parameters taken from the published literature. The program then calculates the optical path through the planetary atmosphere of the radiation from the host star, and quantifies the absorption due to the modelled composition in a transmission spectrum of transit depth as a function of wavelength. The code is written in C++, parallelised using OpenMP, and is available for public download and use from http://www.ucl.ac.uk/exoplanets/.

Hollis, M D J; Tinetti, G

2013-01-01T23:59:59.000Z

135

Dynamic Process of Money Transfer Models  

E-Print Network (OSTI)

We have studied numerically the statistical mechanics of the dynamic phenomena, including money circulation and economic mobility, in some transfer models. The models on which our investigations were performed are the basic model proposed by A. Dragulescu and V. Yakovenko [1], the model with uniform saving rate developed by A. Chakraborti and B.K. Chakrabarti [2], and its extended model with diverse saving rate [3]. The velocity of circulation is found to be inversely related with the average holding time of money. In order to check the nature of money transferring process in these models, we demonstrated the probability distributions of holding time. In the model with uniform saving rate, the distribution obeys exponential law, which indicates money transfer here is a kind of Poisson process. But when the saving rate is set diversely, the holding time distribution follows a power law. The velocity can also be deduced from a typical individual's optimal choice. In this way, an approach for building the micro-...

Wang, Y; Wang, Yougui; Ding, Ning

2005-01-01T23:59:59.000Z

136

Modelling of Radiative Transfer in Light Sources  

E-Print Network (OSTI)

Institute of Applied Physics, RAS, 46 Ulyanov Street, Nizhny Novgorod 603950, Russia I. Y. Dodin and N. J particles could not travel faster than light. Hence, the final energy is estimated from Eq. 52 as a -1 Research through Grant No. 08-02-01209-a and the NNSA under the SSAA Program through DOE Research un- der

Eindhoven, Technische Universiteit

137

Analytical Delta-Four-Stream DoublingAdding Method for Radiative Transfer Parameterizations  

Science Conference Proceedings (OSTI)

Although single-layer solutions have been obtained for the ?-four-stream discrete ordinates method (DOM) in radiative transfer, a four-stream doublingadding method (4DA) is lacking, which enables us to calculate the radiative transfer through a ...

Feng Zhang; Zhongping Shen; Jiangnan Li; Xiuji Zhou; Leiming Ma

2013-03-01T23:59:59.000Z

138

Surface Albedo Estimates from Nimbus-7 ERB Data and a Two-Stream Approximation of the Radiative Transfer Equation  

Science Conference Proceedings (OSTI)

Solar zenith angle-dependent surface albedo is determined by equating top of the atmosphere (TOA) albedo evaluated from Nimbus-7 data with TOA albedo predicted by a two-layer, two-stream radiative transfer model of the atmosphere. Results are ...

Howard W. Barker; John A. Davies

1989-05-01T23:59:59.000Z

139

Radiative Heat Transfer in Enhanced Hydrogen Outgassing of Glass  

E-Print Network (OSTI)

W/m 2 .m) f (?T ) Blackbody radiation function I ? SpectralW/m 2 .sr.m) I b,? Blackbody radiation intensity (W/m 2 .can be treated as blackbody radiation at temperature T sur .

Kitamura, Rei; Pilon, Laurent

2009-01-01T23:59:59.000Z

140

NISTIR 6299 A Heat Transfer Model for Fire Fighter's ...  

Science Conference Proceedings (OSTI)

Page 1. NISTIR 6299 A Heat Transfer Model for Fire Fighter's Protective Clothing William E. Mell J. Randall Lawson United ...

1999-05-06T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Implementation of a simplified approach to radiative transfer in general relativity  

E-Print Network (OSTI)

We describe in detail the implementation of a simplified approach to radiative transfer in general relativity by means of the well-known neutrino leakage scheme (NLS). In particular, we carry out an extensive investigation of the properties and limitations of the NLS for isolated relativistic stars to a level of detail that has not been discussed before in a general-relativistic context. Although the numerous tests considered here are rather idealized, they provide a well-controlled environment in which to understand the relationship between the matter dynamics and the neutrino emission, which is important in order to model the neutrino signals from more complicated scenarios, such as binary neutron-star mergers. When considering nonrotating hot neutron stars we confirm earlier results of one-dimensional simulations, but also present novel results about the equilibrium properties and on how the cooling affects the stability of these configurations. In our idealized but controlled setup, we can then show that deviations from the thermal and weak-interaction equilibrium affect the stability of these models to radial perturbations, leading models that are stable in the absence of radiative losses, to a gravitational collapse to a black hole when neutrinos are instead radiated.

Filippo Galeazzi; Wolfgang Kastaun; Luciano Rezzolla; Jos A. Font

2013-06-20T23:59:59.000Z

142

Microwave radiative transfer in the mixed-phase regions of tropical rainfall  

E-Print Network (OSTI)

Current physically-based Radiative Transfer Model (RTM) algorithms for estimating oceanic rain use a very simplified hydrometeor profile that ignores the mixed-phase regions (Wilheit et al., 1977). However, to estimate hydrometeor profiles more reasonably in the tropical precipitation regions, understanding of the brightness temperature (Tb) variations in the mixed-phase regions is essential. Further, establishing physical assumptions for microwave radiative transfer in the mixed-phase regions is necessary for quantifying and minimizing the uncertainties in the rainfall retrieval. Consequently, the objective of this study was to quantify uncertainties and to achieve a solid basis for improvement of the current rainfall retrieval, which is based on an RTM. To accomplish this, we examined data taken by the Convair-580 aircraft during the KWAJEX (Kwajalein Experiment). In order to calculate radiative transfer, the AMMR (Airborne Multi-channel Microwave Radiometer) data were combined with radiosonde data and aircraft microphysics data. Analyses were performed for the stratiform and convective rainfall regions respectively. In stratiform precipitation with a bright band, the main concern was to examine the needed physical assumptions for describing the abrupt change of Tb just below the freezing level. In the case of convective precipitation, the focus was to investigate the effective additional rain layer thickness corresponding to the super-cooled water layer above the freezing level. From the results, it was required to assume the bright-band (around 1/2 km below the FL) as having 2 times the absorption as the rain below to explain the Tb variation due to the phase change of hydrometeors. On the other hand, in the case of convective rainfall, it was suggested that approximately from 1/4km to 3km of super-cooled layer thickness should be considered to describe the additional hydrometeor layer due to the strong updrafts in the convective regions.

Jin, Kyoung-Wook

2001-01-01T23:59:59.000Z

143

Micrometeorological Modeling of Radiative and Convective Effects with a Building-Resolving Code  

Science Conference Proceedings (OSTI)

In many micrometeorological studies with computational fluid dynamics, building-resolving models usually assume a neutral atmosphere. Nevertheless, urban radiative transfers play an important role because of their influence on the energy budget. ...

Yongfeng Qu; Maya Milliez; Luc Musson-Genon; Bertrand Carissimo

2011-08-01T23:59:59.000Z

144

Full-Spectrum Correlated-k Distribution for Shortwave Atmospheric Radiative Transfer  

Science Conference Proceedings (OSTI)

The full-spectrum correlated k-distribution (FSCK) method, originally developed for applications in combustion systems, is adapted for use in shortwave atmospheric radiative transfer. By weighting k distributions by the solar source function, the ...

Daniel T. Pawlak; Eugene E. Clothiaux; Michael F. Modest; Jason N. S. Cole

2004-11-01T23:59:59.000Z

145

A Revised Cloud Overlap Scheme for Fast Microwave Radiative Transfer in Rain and Cloud  

Science Conference Proceedings (OSTI)

The assimilation of cloud- and precipitation-affected observations into weather forecasting systems requires very fast calculations of radiative transfer in the presence of multiple scattering. At the European Centre for Medium-Range Weather ...

Alan J. Geer; Peter Bauer; Christopher W. ODell

2009-11-01T23:59:59.000Z

146

Estimating Three-Dimensional Cloudy Radiative Transfer Effects from Time-Height Cross Sections  

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

Estimating Three-Dimensional Cloudy Radiative Transfer Estimating Three-Dimensional Cloudy Radiative Transfer Effects from Time-Height Cross Sections C. Hannay and R. Pincus National Oceanic and Atmospheric Administration Climate Diagnostics Center Boulder, Colorado K. F. Evans Program in Atmospheric and Oceanic Sciences University of Colorado Boulder, Colorado Introduction Clouds in the atmosphere are finite in extent and variable in every direction and in time. Long data sets from ground-based profilers, such as lidars or cloud radars, could provide a very valuable set of observations to characterize this variability. We may ask how well such profiling instruments can represent the cloud structure as measured by the magnitude of the three-dimensional (3D) radiative transfer effect. The 3D radiative transfer effect is the difference between the domain average broadband solar surface

147

On the Correlated k-Distribution Method for Radiative Transfer in Nonhomogeneous Atmospheres  

Science Conference Proceedings (OSTI)

The correlated k-distribution method for radiative transfer in nonhomogeneous atmospheres is discussed in terms of the physical and mathematical conditions under which this method is valid. Two correlated conditions are necessary and sufficient ...

Qiang Fu; K. N. Liou

1992-11-01T23:59:59.000Z

148

Near-field thermal radiation transfer controlled by plasmons in graphene  

E-Print Network (OSTI)

It is shown that thermally excited plasmon-polariton modes can strongly mediate, enhance, and tune the near-field radiation transfer between two closely separated graphene sheets. The dependence of near-field heat exchange ...

Ilic, Ognjen

149

Fluctuating-surface-current formulation of radiative heat transfer for arbitrary geometries  

E-Print Network (OSTI)

We describe a fluctuating-surface-current formulation of radiative heat transfer, applicable to arbitrary geometries in both the near and far field, that directly exploits efficient and sophisticated techniques from the ...

Rodriguez, Alejandro W.

150

Trace formulas for nonequilibrium Casimir interactions, heat radiation, and heat transfer for arbitrary objects  

E-Print Network (OSTI)

We present a detailed derivation of heat radiation, heat transfer, and (Casimir) interactions for N arbitrary objects in the framework of fluctuational electrodynamics in thermal nonequilibrium. The results can be expressed ...

Bimonte, Giuseppe

151

Simple Radiative Transfer Methods for Calculating Domain-Averaged Solar Fluxes in Inhomogeneous Clouds  

Science Conference Proceedings (OSTI)

The use of cloud fraction as a means of incorporating horizontal cloud inhomogeneity in radiative transfer calculations is widespread in the atmospheric science community. This study addresses some issues pertaining to the use of cloud fraction ...

P. M. Gabriel; K. F. Evans

1996-03-01T23:59:59.000Z

152

A FourierRiccati Approach to Radiative Transfer. Part I: Foundations  

Science Conference Proceedings (OSTI)

The three-dimensional equation of radiative transfer is formally solved using a Fourier-Riccati approach while calculations are performed on cloudy media embedded in a two-dimensional space. An extension to Stephens work, this study addresses ...

P. M. Gabriel; S-C. Tsay; G. L. Stephens

1993-09-01T23:59:59.000Z

153

Improved Radiative Transfer Calculations from Information Provided by Bulk Microphysical Schemes  

Science Conference Proceedings (OSTI)

Bulk microphysical schemes are providing increasingly detailed information of hydrometeor profiles both within and below clouds. This information can be used to improve radiative transfer calculations with little increase in computation time. In ...

J. C. Petch

1998-05-01T23:59:59.000Z

154

Radiative Transfer through Arbitrarily Shaped Optical Media. Part II. Group Theory and Simple Closures  

Science Conference Proceedings (OSTI)

This paper presents a formulation of the radiative transfer equation which allows for the distinction between various groups of spatial scales of variation that comprise the radiance field. Such a formulation provides a convenient means for ...

Graeme L. Stephens

1988-06-01T23:59:59.000Z

155

A New Look at the Discrete Ordinate Method for Radiative Transfer Calculations in Anisotropically Scattering Atmospheres  

Science Conference Proceedings (OSTI)

The difficulties inherent in the conventional numerical implementation of the discrete ordinate method (following Chandrasekhar's prescription) for solving the radiative transfer equation are discussed. A matrix formulation is developed to ...

Knut Stamnes; Roy A. Swanson

1981-02-01T23:59:59.000Z

156

O Star X-ray Line Profiles Explained by Radiation Transfer in Inhomogeneous Stellar Wind  

E-Print Network (OSTI)

It is commonly adopted that X-rays from O stars are produced deep inside the stellar wind, and transported outwards through the bulk of the expanding matter which attenuates the radiation and affects the shape of emission line profiles. The ability of Chandra and XMM-Newton to resolve these lines spectroscopically provided a stringent test for the theory of X-ray production. It turned out that none of the existing models was able to reproduce the observations consistently. The major caveat of these models was the underlying assumption of a smooth stellar wind. Motivated by the various observational evidence that the stellar winds are in fact structured, we present a 2-D model of a stochastic, inhomogeneous wind. The X-ray radiative transfer is derived for such media. It is shown that profiles from a clumped wind differ drastically from those predicted by conventional homogeneous models. We review the up-to-date observations of X-ray line profiles from stellar winds and present line fits obtained from the inhomogeneous wind model. The necessity to account for inhomogeneities in calculating the X-ray transport in massive star winds, including for HMXB is highlighted.

L. M. Oskinova; A. Feldmeier; W. -R. Hamann

2005-11-01T23:59:59.000Z

157

Fast 2D non-LTE radiative modelling of prominences I. Numerical methods and benchmark results  

E-Print Network (OSTI)

New high-resolution spectropolarimetric observations of solar prominences require improved radiative modelling capabilities in order to take into account both multi-dimensional - at least 2D - geometry and complex atomic models. This makes necessary the use of very fast numerical schemes for the resolution of 2D non-LTE radiative transfer problems considering freestanding and illuminated slabs. The implementation of Gauss-Seidel and successive over-relaxation iterative schemes in 2D, together with a multi-grid algorithm, is thoroughly described in the frame of the short characteristics method for the computation of the formal solution of the radiative transfer equation in cartesian geometry. We propose a new test for multidimensional radiative transfer codes and we also provide original benchmark results for simple 2D multilevel atom cases which should be helpful for the further development of such radiative transfer codes, in general.

L. Leger; L. Chevallier; F. Paletou

2007-03-27T23:59:59.000Z

158

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

159

Engineering Model of Liquid Storage Utility Tank for Heat Transfer Analysis  

SciTech Connect

The utility or chemical storage tank requires special engineering attention and heat transfer analysis because the tank content is very sensitive to temperature and surrounding environment such as atmospheric or outside air, humidity, and solar radiation heat. A simplified heat transfer model was developed to calculate the liquid content temperature of utility storage tank. The content of the utility storage tanks can be water or any other chemical liquid. An engineering model of liquid storage tank for heat transfer analysis and temperature calculations are presented and discussed in the examples of Tanks No. 1 containing oxalic acid and No. 2 containing sodium tetraphenylborate solution.

Kwon, K.C.

1995-09-27T23:59:59.000Z

160

A 2-D Test Problem for CFD Modeling Heat Transfer in Spent Fuel Transfer Cask Neutron Shields  

SciTech Connect

In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 5-10 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper presents results for a simple 2-D problem that is an effective numerical analog for the neutron shield application. Because it is 2-D, solutions can be obtained relatively quickly allowing a comparison and assessment of sensitivity to model parameter changes. Turbulence models are considered as well as the tradeoff between steady state and transient solutions. Solutions are compared for two commercial CFD codes, FLUENT and STAR-CCM+. The results can be used to provide input to the CFD Best Practices for this application. Following study results for the 2-D test problem, a comparison of simulation results is provided for a high Rayleigh number experiment with large annular gap. Because the geometry of this validation is significantly different from the neutron shield, and due to the critical nature of this application, the argument is made for new experiments at representative scales

Zigh, Ghani; Solis, Jorge; Fort, James A.

2011-01-14T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

The multiple absorption coefficient zonal method (MACZM), an efficient computational approach for the analysis of radiative heat transfer in multidimensional inhomogeneous nongray media  

E-Print Network (OSTI)

of Radiative Heat Transfer, the P-3 Approximation, AIAAMedia, Journal of Heat Transfer, Vol. 109, No. 3 (1987),Media, Numerical Heat Transfer, Part B, Fundamentals, Vol.

Yuen, W W

2006-01-01T23:59:59.000Z

162

AN ANALYTIC RADIATIVE-CONVECTIVE MODEL FOR PLANETARY ATMOSPHERES  

Science Conference Proceedings (OSTI)

We present an analytic one-dimensional radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power-law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric-pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries; (2) worlds with some attenuation of sunlight throughout the atmosphere, which we show can produce either shallow or deep radiative-convective boundaries, depending on the strength of sunlight attenuation; and (3) strongly irradiated giant planets (including hot Jupiters), where we explore the conditions under which these worlds acquire detached convective regions in their mid-tropospheres. Finally, we validate our model and demonstrate its utility through comparisons to the average observed thermal structure of Venus, Jupiter, and Titan, and by comparing computed flux profiles to more complex models.

Robinson, Tyler D. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Catling, David C., E-mail: robinson@astro.washington.edu [Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 (United States)

2012-09-20T23:59:59.000Z

163

Modelling Carbon with Transferable Empirical Potentials  

Science Conference Proceedings (OSTI)

Complexities associated with hybridization and anisotropy meant that transferable potentials for carbon were slow to emerge, lagging decades behind similar...

164

Trace formulae for non-equilibrium Casimir interactions, heat radiation and heat transfer for arbitrary objects  

E-Print Network (OSTI)

We present a detailed derivation of heat radiation, heat transfer and (Casimir) interactions for N arbitrary objects in the framework of fluctuational electrodynamics in thermal non-equilibrium. The results can be expressed as basis-independent trace formulae in terms of the scattering operators of the individual objects. We prove that heat radiation of a single object is positive, and that heat transfer (for two arbitrary passive objects) is from the hotter to a colder body. The heat transferred is also symmetric, exactly reversed if the two temperatures are exchanged. Introducing partial wave-expansions, we transform the results for radiation, transfer and forces into traces of matrices that can be evaluated in any basis, analogous to the equilibrium Casimir force. The method is illustrated by (re)deriving the heat radiation of a plate, a sphere and a cylinder. We analyze the radiation of a sphere for different materials, emphasizing that a simplification often employed for metallic nano-spheres is typically invalid. We derive asymptotic formulae for heat transfer and non-equilibrium interactions for the cases of a sphere in front a plate and for two spheres, extending previous results. As an example, we show that a hot nano-sphere can levitate above a plate with the repulsive non-equilibrium force overcoming gravity -- an effect that is not due to radiation pressure.

Matthias Krger; Giuseppe Bimonte; Thorsten Emig; Mehran Kardar

2012-07-02T23:59:59.000Z

165

Numerical heat transfer attic model using a radiant barrier system  

Science Conference Proceedings (OSTI)

A two-dimensional, steady-state finite-element model was developed to simulate the thermal effects of the application of an attic radiant barrier system (ARBS) inside a ventilated residential attic. The attic is ventilated using the exhaust air from an evaporative cooler. The study uses a {kappa}-{epsilon} turbulent model to describe the velocity and temperature distributions in the attic. The ambient temperature and solar isolation densities on the outside inclined attic surfaces are used as driving functions for the model. The model also included the appropriate heat exchange modes of convection and radiation on these outside surfaces. Several recirculation zones were visually observed in the attic flow pattern. Also, the use of the ARBS seems to lower the heat transfer through the ceiling by 25--30%, but this effect decreases significantly as the outside ventilation rates are increased through the attic space. The 2D model revealed some interesting temperature distributions along the attic surfaces that could not have been predicted by the one-dimensional models. The lower emissivity ARBS seems to raise the temperature of the inclined attic surfaces as well as the temperature of the exhausted ventilation air.

Moujaes, S.F.; Alsaiegh, N.T.

2000-04-01T23:59:59.000Z

166

Multimode Radiative Transfer in Finite Optical Media. II: Solutions  

Science Conference Proceedings (OSTI)

This paper extends the theoretical developments of Part I to illustrate the power of the method in solving multiple scattering problems with sources that result from i) the single scatter of a collimated beam of solar radiation that is directly ...

Graeme L. Stephens; Rudolph W. Preisendorfer

1984-03-01T23:59:59.000Z

167

CFD Modelling of Heat Transfer in Supersonic Nozzles for ... - TMS  

Science Conference Proceedings (OSTI)

May 1, 2007 ... CFD Modelling of Heat Transfer in Supersonic Nozzles for Magnesium Production by Peter Witt, M.N.H. Khan, and Geoffrey Brooks...

168

Radiative component and combined heat transfer in the thermal calculation of finned tube banks  

Science Conference Proceedings (OSTI)

For more exact calculation of combined heat transfer in the case of finned tube banks (e.g., in the convective section of a furnace), the radiative heat transfer cannot be neglected. A new method for relatively simple calculation of total heat flux (convection + radiation + conduction in fins) is fully compatible with that for bare tube banks/bundles developed earlier. It is based on the method of radiative coefficients. However, the resulting value of heat flux must be corrected due to fin thickness and especially due to the fin radiative influence. For this purpose the so-called multiplicator of heat flux was introduced. The applicability of this methods has been demonstrated on a tubular fired heater convective section. A developed computer program based on the method has also been used for an analysis of the influence of selected parameters to show the share of radiation on the total heat flux.

Stehlik, P. [Technical Univ. of Brno (Czech Republic). Dept. of Process Engineering] [Technical Univ. of Brno (Czech Republic). Dept. of Process Engineering

1999-01-01T23:59:59.000Z

169

Modeling Ultraviolet Radiation at the Earth's Surface. Part I: The Sensitivity of Ultraviolet Irradiances to Atmospheric Changes  

Science Conference Proceedings (OSTI)

A discrete-ordinate radiative transfer model is employed for the prediction of surface UV irradiances. A wide-ranging sensitivity study is undertaken to show how changes to the model input parameters aged UV irradiances at the surface. The ...

Piers M. De F. Forster

1995-11-01T23:59:59.000Z

170

Improved Simulation of Clear-Sky Shortwave Radiative Transfer in the CCC-GCM  

Science Conference Proceedings (OSTI)

The disposition of mean July clear-sky solar radiation in the Canadian Climate Centre second-generation general circulation model (CCC-GCMII) was analyzed by comparing top of the atmosphere (TOA) net fluxes with earth radiation budget experiment (...

Howard W. Barker; Zhanqing Li

1995-09-01T23:59:59.000Z

171

Modeling early galaxies using radiation hydrodynamics  

Science Conference Proceedings (OSTI)

This simulation uses a flux-limited diffusion solver to explore the radiation hydrodynamics of early galaxies, in particular, the ionizing radiation created by Population III stars. At the time of this rendering, the simulation has evolved to a redshift ... Keywords: astrophysics, modeling, visualization

Joseph A. Insley; Rick Wagner; Robert Harkness; Daniel R. Reynolds; Michael L. Norman; Mark Hereld; Eric C. Olson; Michael E. Papka; Venkatram Vishwanath

2011-11-01T23:59:59.000Z

172

DoublingAdding Method for Delta-Four-Stream Spherical Harmonic Expansion Approximation in Radiative Transfer Parameterization  

Science Conference Proceedings (OSTI)

Though the single-layer solutions have been found for the ?-four-stream spherical harmonic expansion method (SHM) in radiative transfer, there is lack of a corresponding doublingadding method (4SDA), which enables the calculation of radiative ...

Feng Zhang; Jiangnan Li

2013-10-01T23:59:59.000Z

173

Decomposition of radiational effects of model feedbacks  

SciTech Connect

Three separate doubled CO/sub 2/ experiments with the statistical dynamic model are used to illustrate efforts to study the climate dynamics, feedbacks, and interrelationships of meteorological parameters by decomposing and isolating their individual effects on radiation transport.

Ellsaesser, H.W.; MacCracken, M.C.; Potter, G.L.; Mitchell, C.S.

1981-08-01T23:59:59.000Z

174

Parallel Jacobian-free Newton Krylov solution of the discrete ordinates method with flux limiters for 3D radiative transfer  

Science Conference Proceedings (OSTI)

The present study introduces a parallel Jacobian-free Newton Krylov (JFNK) general minimal residual (GMRES) solution for the discretized radiative transfer equation (RTE) in 3D, absorbing, emitting and scattering media. For the angular and spatial discretization ... Keywords: Collimated radiation, Discrete ordinates method (DOM) SN, Electromagnetic radiation, Flux limiters, General Minimal Residual (GMRES), Gram-Schmidt, Householder, Jacobian free Newton-Krylov (JFNK), Parallel MPI, Radiative transfer equation (RTE), TVD, Threads

William F. Godoy; Xu Liu

2012-06-01T23:59:59.000Z

175

Simulating 3-D Radiative Transfer Effects over the Sierra Nevada Mountains using WRF  

Science Conference Proceedings (OSTI)

A surface solar radiation parameterization based on deviations between 3-D and conventional plane-parallel radiative transfer models has been incorporated into the Weather Research and Forecasting (WRF) model to understand the solar insolation over mountain/snow areas and to investigate the impact of the spatial and temporal distribution and variation of surface solar fluxes on land-surface processes. Using the Sierra-Nevada in the western United States as a testbed, we show that mountain effect could produce up to ?50 to + 50Wm?2 deviations in the surface solar fluxes over the mountain areas, resulting in a temperature increase of up to 1 C on the sunny side. Upward surface sensible and latent heat fluxes are modulated accordingly to compensate for the change in surface solar fluxes. Snow water equivalent and surface albedo both show decreases on the sunny side of the mountains, indicating more snowmelt and hence reduced snow albedo associated with more solar insolation due to mountain effect. Soil moisture increases on the sunny side of the mountains due to enhanced snowmelt, while decreases on the shaded side. Substantial differences are found in the morning hours from 8-10 a.m. and in the afternoon around 3-5 p.m., while differences around noon and in the early morning and late afternoon are comparatively smaller. Variation in the surface energy balance can also affect atmospheric processes, such as cloud fields, through the modulation of vertical thermal structure. Negative changes of up to ?40 gm?2 are found in the cloud water path, associated with reductions in the surface insolation over the cloud region. The day-averaged deviations in the surface solar flux are positive over the mountain areas and negative in the valleys, with a range between ?12~12Wm?2. Changes in sensible and latent heat fluxes and surface skin temperature follow the solar insolation pattern. Differences in the domain-averaged diurnal variation over the Sierras show that the mountain area receives more solar insolation during early morning and late afternoon, resulting in enhanced upward sensible heat and latent heat fluxes from the surface and a corresponding increase in surface skin temperature. During the middle of the day, however, the surface insolation and heat fluxes show negative changes, indicating a cooling effect. Hence overall, the diurnal variations of surface temperature and surface fluxes in the Sierra-Nevada are reduced through the interactions of radiative transfer and mountains. The hourly differences of the surface solar insolation in higher elevated regions, however, show smaller magnitude in negative changes during the middle of the day and possibly more solar fluxes received during the whole day.

Gu, Yu; Liou, K. N.; Lee, W- L.; Leung, Lai-Yung R.

2012-10-30T23:59:59.000Z

176

Radiative effects of a CO/sub 2/ increase: results of a model comparison  

SciTech Connect

A comparison of infrared radiative transfer models is announced. The initial phase is underway, with other phases scheduled through 1984. The results of the ir model comparison will be included in the state-of-the-art report on climate modeling. Although the time scale for completion of the comparison is a few years, significant preliminary results have already been obtained. (PSB)

Luther, F.M.

1982-10-07T23:59:59.000Z

177

Modeling Surface Solar Radiation: Model Formulation and Validation  

Science Conference Proceedings (OSTI)

A model for computing global solar radiation at the surface was formulated for use with satellite observations. A compromise in the approach was necessary, whereby the model accuracy and the inherent limitations of satellite observations were ...

R. T. Pinker; J. A. Ewing

1985-05-01T23:59:59.000Z

178

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

179

Net Exchange Reformulation of Radiative Transfer in the CO2 15-?m Band on Mars  

Science Conference Proceedings (OSTI)

The net exchange formulation (NEF) is an alternative to the usual radiative transfer formulation. It was proposed by two authors in 1967, but until now, this formulation has been used only in a very few cases for atmospheric studies. The aim of ...

Jean-Louis Dufresne; Richard Fournier; Christophe Hourdin; Frdric Hourdin

2005-09-01T23:59:59.000Z

180

Analytic Greens Function for Radiative Transfer in Plane-Parallel Atmospheres  

Science Conference Proceedings (OSTI)

Greens function is a widely used approach for boundary value problems. In problems related to radiative transfer, Greens function has been found to be useful in land, ocean, and atmosphere remote sensing. It is also a key element in higher ...

Yi Qin; Michael A. Box

2005-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

MEAM with Charge Transfer for TM Oxide Modeling  

Science Conference Proceedings (OSTI)

Abstract Scope, Transition metal (TM) oxides are important material with diverse applications including ... Density functional theory (DFT) modeling studies have provided useful bulk ... Atomistic Modeling of Radiation Damage in bcc Uranium.

182

Solar Radiative Transfer in Clouds with Vertical Internal Inhomogeneity  

Science Conference Proceedings (OSTI)

To investigate the photon transport in inhomogeneous clouds, a Monte Carlo cloud model with internal variation of optical properties is developed. The data for cloud vertical internal inhomogeneity are chosen from published observations. ...

J. Li; D. J. W. Geldart; Petr Chlek

1994-09-01T23:59:59.000Z

183

Radiative transfer and thermal performance levels in foam insulation boardstocks  

E-Print Network (OSTI)

The validity of predictive models for the thermal conductivity of foam insulation is established based on the fundamental geometry of the closed-cell foam. The extinction coefficient is experimentally and theoretically ...

Moreno, John David

1991-01-01T23:59:59.000Z

184

Explicit-implicit difference scheme for the joint solution of the radiative transfer and energy equations by the splitting method  

Science Conference Proceedings (OSTI)

High-order accurate explicit and implicit conservative predictor-corrector schemes are presented for the radiative transfer and energy equations in the multigroup kinetic approximation solved together by applying the splitting method with respect to ... Keywords: difference splitting schemes, radiative transfer equations

N. Ya. Moiseev

2013-03-01T23:59:59.000Z

185

Advanced Model and Methodology Development [Heat Transfer and Fluid  

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

Advanced Model and Advanced Model and Methodology Development Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Advanced Model and Methodology Development Electrorefiner Model for Treatment of Spent Nuclear Fuel Electrorefiner Model for Treatment of Spent Nuclear Fuel. Click on image to

186

MODELING OF HEAT TRANSFER IN ROOMS IN THE MODELICA  

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

MODELING MODELING OF HEAT TRANSFER IN ROOMS IN THE MODELICA "BUILDINGS" LIBRARY Michael Wetter, Wangda Zuo, Thierry Stephane Nouidui Simulation Research Group, Building Technologies Department Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720, USA ABSTRACT This paper describes the implementation of the room heat transfer model in the free open-source Modelica "Buildings" library. The model can be used as a single room or to compose a multizone building model. We discuss how the model is de- composed into submodels for the individual heat transfer phenomena. We also discuss the main physical assumptions. The room model can be parameterized to use di↵erent modeling assump- tions, leading to linear or non-linear di↵erential algebraic systems of equations. We present nu- merical experiments that show

187

Implementing the Delta-Four-Stream Approximation for Solar Radiation Computations in an Atmosphere General Circulation Model  

Science Conference Proceedings (OSTI)

Proper quantification of the solar radiation budget and its transfer within the atmosphere is of utmost importance in climate modeling. The delta-four-stream (DFS) approximation has been demonstrated to offer a more accurate computational method ...

Tarek Ayash; Sunling Gong; Charles Q. Jia

2008-07-01T23:59:59.000Z

188

Estimation and Model Validation of Surface Solar Radiation and Cloud Radiative Forcing Using TOGA COARE Measurements  

Science Conference Proceedings (OSTI)

The Tropical Ocean and Global Atmosphere Coupled OceanAtmosphere Response Experiment (TOGA COARE) radiation measurements in the western Pacific warm pool are used to estimate surface solar radiation budgets and to validate radiation model ...

Ming-Dah Chou; Wenzhong Zhao

1997-04-01T23:59:59.000Z

189

Measure of Diffusion Model Error for Thermal Radiation Transport  

E-Print Network (OSTI)

The diffusion approximation to the equation of transfer (Boltzmann transport equation) is usually applied to media where scattering dominates the interactions. Diffusion approximation helps in significant savings in terms of code complexity and computational time. However, this approximation often has significant error. Error due to the inherent nature of a physics model is called model error. Information about the model error associated with the diffusion approximation is clearly desirable. An indirect measure of model error is a quantity that is related in some way to the error but not equal to the error. In general, indirect measures of error are expected to be less costly than direct measures. Perhaps the most well-known indirect measure of the diffusion model error is the variable-Eddington tensor. This tensor provides a great deal of information about the angular dependence of the angular intensity solution, but it is not always simple to interpret. We define a new indirect measure of the diffusion model error called the diffusion model error source (DME source). When this DME source is added to the diffusion equation, the transport solution for the angular-integrated intensity is obtained. In contrast to the variable-Eddington tensor, our DME source is a scalar that is conceptually easy to interpret. In addition to defining the DME source analytically, we show how to generate this source numerically relative to the Sn radiative transfer equations with linear-discontinuous spatial discretization. This numerical source is computationally tested and shown to reproduce the Sn solution for a number of problems. Our radiative transfer model solves a coupled, time dependent, multi-frequency, 1-D slab equation and material heat transfer equation. We then use diffusion approximation to solve the same problem. The difference due to this approximation can be modelled by a diffusion source. The diffusion source is defined as an amount of inhomogeneous source that, when added to a diffusion calculation, gives a solution for the angle-integrated intensity that is equal to the transport solution.

Kumar, Akansha

2013-05-01T23:59:59.000Z

190

Incorporating Radiation Effects into Edge Plasma Transport Models with Extended Atomic Data Tables  

DOE Green Energy (OSTI)

Plasmas at the tokamak edge can be very optically thick to hydrogen resonance lines. The resulting strong line radiation can significantly affect the ionization and energy balance in these plasmas. One method of account for effects is to self-consistently couple a partially ionized plasma transport model with a nonlocal thermodynamic equilibrium (NLTE) model incorporating line radiation transfer. This approach has been implemented in one dimension, but would be computationally challenging and expensive to implement in multiple dimensions. Approximate treatments of radiation transfer can decrease the computational time, but would still require coupling to a multidimensional plasma transport model to address realistic geometries, e.g. the tokamak divertor. Here, we consider the development of atomic hydrogen data tables that include radiation interactions and can be easily applied to multidimensional geometries.

Scott, H A; Adams, M L

2004-06-14T23:59:59.000Z

191

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

resolved Radiative Transfer Model: MODTRAN.131 APMEXModerate Imaging Spectroradiometer MODTRAN MODerate spectralprovide by MODTRAN133 Table 4.2

Zhu, Aihua

2010-01-01T23:59:59.000Z

192

A New Narrowband Radiation Model for Water Vapor Absorption  

Science Conference Proceedings (OSTI)

The accuracy of radiation models is a critical issue in climate studies. However, calculations from different radiation models used in climate calculations disagree with one another, and with more detailed models, at levels significant to many ...

Juying X. Warner; Robert G. Ellingson

2000-05-01T23:59:59.000Z

193

Some analytical models of radiating collapsing spheres  

Science Conference Proceedings (OSTI)

We present some analytical solutions to the Einstein equations, describing radiating collapsing spheres in the diffusion approximation. Solutions allow for modeling physical reasonable situations. The temperature is calculated for each solution, using a hyperbolic transport equation, which permits to exhibit the influence of relaxational effects on the dynamics of the system.

Herrera, L.; Di Prisco, A [Escuela de Fisica, Facultad de Ciencias, Universidad Central de Venezuela, Caracas (Venezuela); Ospino, J. [Area de Fisica Teorica. Facultad de Ciencias, Universidad de Salamanca Salamanca (Spain)

2006-08-15T23:59:59.000Z

194

Thermal heat radiation, near-field energy density and near-field radiative heat transfer of coated materials  

E-Print Network (OSTI)

We investigate the thermal radiation and thermal near-field energy density of a metal-coated semi-infinite body for different substrates. We show that the surface polariton coupling within the metal coating leads to an enhancement of the TM-mode part of the thermal near-field energy density when a polar substrate is used. In this case the result obtained for a free standing metal film is retrieved. In contrast, in the case of a metal substrate there is no enhancement in the TM-mode part, as can also be explained within the framework of surface plasmon coupling within the coating. Finally, we discuss the influence of the enhanced thermal energy density on the near-field radiative heat transfer between a simple semi-infinite and a coated semi-infinite body for different material combinations.

Biehs, Svend-Age

2011-01-01T23:59:59.000Z

195

Thermal heat radiation, near-field energy density and near-field radiative heat transfer of coated materials  

E-Print Network (OSTI)

We investigate the thermal radiation and thermal near-field energy density of a metal-coated semi-infinite body for different substrates. We show that the surface polariton coupling within the metal coating leads to an enhancement of the TM-mode part of the thermal near-field energy density when a polar substrate is used. In this case the result obtained for a free standing metal film is retrieved. In contrast, in the case of a metal substrate there is no enhancement in the TM-mode part, as can also be explained within the framework of surface plasmon coupling within the coating. Finally, we discuss the influence of the enhanced thermal energy density on the near-field radiative heat transfer between a simple semi-infinite and a coated semi-infinite body for different material combinations.

Svend-Age Biehs

2011-03-15T23:59:59.000Z

196

Non-contact pumping of light emitters via non-radiative energy transfer  

DOE Patents (OSTI)

A light emitting device is disclosed including a primary light source having a defined emission photon energy output, and, a light emitting material situated near to said primary light source, said light emitting material having an absorption onset equal to or less in photon energy than the emission photon energy output of the primary light source whereby non-radiative energy transfer from said primary light source to said light emitting material can occur yielding light emission from said light emitting material.

Klimov, Victor I. (Los Alamos, NM); Achermann, Marc (Los Alamos, NM)

2010-01-05T23:59:59.000Z

197

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

198

Heat transfer performance of an external receiver pipe under unilateral concentrated solar radiation  

Science Conference Proceedings (OSTI)

The heat transfer and absorption characteristics of an external receiver pipe under unilateral concentrated solar radiation are theoretically investigated. Since the heat loss ratio of the infrared radiation has maximum at moderate energy flux, the heat absorption efficiency will first increase and then decrease with the incident energy flux. The local absorption efficiency will increase with the flow velocity, while the wall temperature drops quickly. Because of the unilateral concentrated solar radiation and different incident angle, the heat transfer is uneven along the circumference. Near the perpendicularly incident region, the wall temperature and absorption efficiency slowly approaches to the maximum, while the absorption efficiency sharply drops near the parallelly incident region. The calculation results show that the heat transfer parameters calculated from the average incident energy flux have a good agreement with the average values of the circumference under different boundary conditions. For the whole pipe with coating of Pyromark, the absorption efficiency of the main region is above 85%, and only the absorption efficiency near the parallelly incident region is below 80%. In general, the absorption efficiency of the whole pipe increases with flow velocity rising and pipe length decreasing, and it approaches to the maximum at optimal concentrated solar flux. (author)

Jianfeng, Lu; Jing, Ding [School of Engineering, Sun Yat-Sen University, Guangzhou 510006 (China); Jianping, Yang [Key Laboratory of Enhanced Heat Transfer and Energy Conservation of the Ministry of Education, South China University of Technology, Guangzhou 510640 (China)

2010-11-15T23:59:59.000Z

199

Development of a Heat Transfer Model for the Integrated Facade Heating  

E-Print Network (OSTI)

Faade heating is a special application of radiant heating and cooling technology and is used to enhance the indoor comfort level of offices, hotels and museums. Mullion radiators are typically used to implement faade heating. This paper analyzes the heat transfer process of facade heating (mullion radiators) in a pilot research project in Pittsburgh, PA. The heat transfer model for facade heating is developed and verified by measured data. The comparison shows that the heat transfer model predicts the measured temperatures with a root mean squared error (RMSE) of the hot water return temperature, the mullion surface temperature, and the window surface temperature of 0.90F, 0.98F and 1.15F, respectively. The factors which affect the heating capacity of mullion radiators have been analyzed. The analysis shows that the supply water temperature is the primary factor which affects the heating or cooing capacity of window mullions and the mullion surface temperature. Return water temperature and mullion surface temperature are quasi-linear functions often water supply temperature. Mullion surface temperature, indoor air temperature gradient on the glazing surface within one foot from mullions is much higher than in the central part of the window. The temperatures in the central 2 feet of a 4-foot window show almost no influence by the mullion surface temperature. Also, the conductive thermal resistance of the mullion double tubes with fillings between two tubes plays a decisive role in controlling the mullion and window frame temperatures.

Gong, X.; Archer, D. H.; Claridge, D. E.

2007-01-01T23:59:59.000Z

200

Two-Stream Approximations to Radiative Transfer in Planetary Atmospheres: A Unified Description of Existing Methods and a New Improvement  

Science Conference Proceedings (OSTI)

Existing two-stream approximations to radiative transfer theory for particulate media are shown to be represented by identical forms of coupled differential equations if the intensity is replaced by integrals of the intensity over hemispheres. ...

W. E. Meador; W. R. Weaver

1980-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

An Assessment of the Parameterization of Subgrid-Scale Cloud Effects on Radiative Transfer. Part II: Horizontal Inhomogeneity  

Science Conference Proceedings (OSTI)

The role of horizontal inhomogeneity in radiative transfer through cloud fields is investigated within the context of the two-stream approximation. Spatial correlations between cloud optical properties and the radiance field are introduced in the ...

Norman B. Wood; Philip M. Gabriel; Graeme L. Stephens

2005-08-01T23:59:59.000Z

202

THERM: Two-Dimensional Building Heat-Transfer Modeling  

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

5 5 THERM: Two-Dimensional Building Heat-Transfer Modeling For more information and to download THERM, please visit our website: http://windows.lbl.gov/software/therm The Windows and Daylighting Group's two-year-old computer program THERM 1.0 is a state-of-the-art tool for modeling two-dimensional heat-transfer effects in building components. The thermal property information THERM provides is important for the design and application of building components such as windows, walls, foundations, roofs and doors. This Microsoft Windows-based program has great potential to users such as building component manufacturers, educators, students, architects, engineers and others who are interested in assessing the heat-transfer properties of single products, product interactions, or integrated systems. THERM

203

Radiation field modeling and optimization of a compact and modular  

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

Radiation field modeling and optimization of a compact and modular Radiation field modeling and optimization of a compact and modular multi-plate photocatalytic reactor (MPPR) for air/water purification by Monte Carlo method Title Radiation field modeling and optimization of a compact and modular multi-plate photocatalytic reactor (MPPR) for air/water purification by Monte Carlo method Publication Type Journal Article Year of Publication 2013 Authors Zazueta, Ana Luisa Loo, Hugo Destaillats, and Gianluca Li Puma Journal Chemical Engineering Journal Volume 217 Pagination 475-485 Date Published 02/01/2013 Abstract The radiation field in a multi-plate photocatalytic reactor (MPPR) for air or water purification was modeled and optimized using a Monte Carlo stochastic method. The MPPR consists of parallel photocatalytic plates irradiated by cylindrical UV lamps orthogonal to the plates. The photocatalyst titanium dioxide (TiO2) is supported on the plates as a thin film. The photoreactor design is compact and offers a large irradiated photocatalytic surface area, a high degree of photon utilization, low pressure drop and a modular design which can facilitate scale-up. These features are desirable for the decontamination of indoor air in ventilation ducts or for water detoxification. The Monte Carlo method was applied to determine three dimensionless reactor performance parameters: the photon absorption efficiency (Φ), the uniformity of the distribution of the dimensionless radiation intensity (η) and the overall photonic efficiency (Φ). The emission of photons from the light sources was simulated by the extensive source with superficial emission (ESSE) model. Simulations were performed by varying the catalyst reflectivity albedo, the number and the diameter of lamps, and the dimensions and spacing of the photocatalytic plates. Optimal design for a basic reactor module with one lamp was accomplished for lamp-diameter-to-plate-height ratio (β) of 0.7, while the plate-spacing-to-plate-height ratio (α) was correlated by [αoptimum = 0.191 β2 - 0.5597 β + 0.3854]. A multilamp arrangement leads to a feasible increase in the size and number of the plates and the irradiated photocatalytic surface area. The optimum design was validated by measuring the apparent quantum yield of the oxidation of toluene (7 ppmv) in a humidified air stream using immobilized TiO2 (Degussa P25). Experiments performed varying the geometrical parameter α correlated well with the model calculations, with maximum apparent quantum yield for α = 0.137. The results are directly transferable to the treatment of water by photocatalysis.

204

Posters Radiation Impacts on Global Climate Models F. Baer, N. Arsky, and K. Rocque  

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

5 5 Posters Radiation Impacts on Global Climate Models F. Baer, N. Arsky, and K. Rocque University of Maryland College Park, Maryland Climate Prediction and Radiative Heating Climate models are driven by forcing, and these forces are seen primarily by the thermal field in general circulation models (GCMs). The major forces that affect the thermal field are longwave radiative (LWR) heating, shortwave radiative (SWR) heating, and convection (cumulus, etc.). These forcing effects are cycled through the thermal field to the motion field by nonlinear transfer. The dependent variables-in particular, temperature (T), moisture (Q) and especially clouds-evolve in time in a model and determine the subsequent forcing. If the dependent variables are not accurately calculated in space and time, the forcing

205

Radiative heat transfer between two dielectric nanogratings in the scattering approach  

E-Print Network (OSTI)

We present a theoretical study of radiative heat transfer between dielectric nanogratings in the scattering approach. As a comparision with these exact results, we also evaluate the domain of validity of Derjaguin's Proximity Approximation (PA). We consider a system of two corrugated silica plates with various grating geometries, separation distances, and lateral displacement of the plates with respect to one another. Numerical computations show that while the PA is a good approximation for aligned gratings, it cannot be used when the gratings are laterally displaced. We illustrate this by a thermal modulator device for nanosystems based on such a displacement.

J. Lussange; R. Gurout; F. S. S. Rosa; J. -J. Greffet; A. Lambrecht; S. Reynaud

2012-06-01T23:59:59.000Z

206

Unified Model for the Heat Transfer Processes that Occur During  

E-Print Network (OSTI)

A unified general model for the heat transfer processes that occur within a food product subjected to canning or aseptic thermal treatment, is presented. Two principles are extensively used in the model building process: system segregation and energy balancing. The model is summarized in an algorithm, whose specification is showed for different combinations of processing system type (PST) and product formulation (PF) with a single particle type. A discussion on the practical relevance of proper product identification in the case of aseptic processing, is included. Finally, an illustration is given on the results that can be obtained from the model algorithm application, in a comparative study of different PST-PF combinations.

Jose F. Pastrana; Harvey J. Gold; Kenneth R. Swanzel; Pastrana Gold; Jose F. Pastrana; Harvey J. Gold; Kenneth R. Swartzel

1992-01-01T23:59:59.000Z

207

Modeling of Heat Transfer in Rooms in the Modelica Buildings Library  

E-Print Network (OSTI)

infrared radia- tion and solar radiation. Figure 1 shows theIn the window model, a solar radiation balance is solved forexterior shade. The model solar radiation balance implements

Wetter, Michael

2013-01-01T23:59:59.000Z

208

RADIATION HEAT TRANSFER ENVIRONMENT IN FIRE AND FURNACE TESTS OF RADIOACTIVE MATERIALS PAKCAGES  

SciTech Connect

The Hypothetical Accident Conditions (HAC) sequential test of radioactive materials packages includes a thermal test to confirm the ability of the package to withstand a transportation fire event. The test specified by the regulations (10 CFR 71) consists of a 30 minute, all engulfing, hydrocarbon fuel fire, with an average flame temperature of at least 800 C. The requirements specify an average emissivity for the fire of at least 0.9, which implies an essentially black radiation environment. Alternate test which provide equivalent total heat input at the 800 C time averaged environmental temperature may also be employed. When alternate tests methods are employed, such as furnace or gaseous fuel fires, the equivalence of the radiation environment may require justification. The effects of furnace and open confinement fire environments are compared with the regulatory fire environment, including the effects of gases resulting from decomposition of package overpack materials. The results indicate that furnace tests can produce the required radiation heat transfer environment, i.e., equivalent to the postulated pool fire. An open enclosure, with transparent (low emissivity) fire does not produce an equivalent radiation environment.

Smith, A

2008-12-31T23:59:59.000Z

209

A Multilayer Upper-Boundary Condition for Longwave Radiative Flux to Correct Temperature Biases in a Mesoscale Model  

Science Conference Proceedings (OSTI)

An upper-level cold bias in potential temperature tendencies of 10 K day?1, strongest at the top of the model, is observed in Weather Research and Forecasting (WRF) model forecasts. The bias originates from the Rapid Radiative Transfer Model ...

Steven M. Cavallo; Jimy Dudhia; Chris Snyder

2011-06-01T23:59:59.000Z

210

Heat Transfer Modeling of Dry Spent Nuclear Fuel Storage Facilities  

Science Conference Proceedings (OSTI)

The present work was undertaken to provide heat transfer model that accurately predicts the thermal performance of dry spent nuclear fuel storage facilities. One of the storage configurations being considered for DOE Aluminum-clad Spent Nuclear Fuel (Al-SNF), such as the Material and Testing Reactor (MTR) fuel, is in a dry storage facility. To support design studies of storage options a computational and experimental program has been conducted at the Savannah River Site (SRS). The main objective is to develop heat transfer models including natural convection effects internal to an interim dry storage canister and to geological codisposal Waste Package (WP). Calculated temperatures will be used to demonstrate engineering viability of a dry storage option in enclosed interim storage and geological repository WP and to assess the chemical and physical behaviors of the Al-SNF in the dry storage facilities. The current paper describes the modeling approaches and presents the computational results along with the experimental data.

Lee, S.Y.

1999-01-13T23:59:59.000Z

211

Spatial and Temporal Transferability of a Distributed Energy-Balance Glacier Melt Model  

Science Conference Proceedings (OSTI)

Modeling melt from glaciers is crucial to assessing regional hydrology and eustatic sea level rise. The transferability of such models in space and time has been widely assumed but rarely tested. To investigate melt model transferability, a ...

Andrew H. MacDougall; Gwenn E. Flowers

2011-03-01T23:59:59.000Z

212

LABORATORY MODELLING OF THE EARTH RADIATION BELT  

E-Print Network (OSTI)

Method of the laboratory modelling of the Earth radiation belt is presented. Method can be used for the estimation of consequences of global energetic and communication projects realizations. The radiation belt of the Earth is the inner part of the magnetosphere, in which the geomagnetic field hold charged particles with kinetic energy from 10 KeV to 100 MeV. This belt play the essential role for the sun radiation regime for the Earth and for the electromagnetic waves propagation. As it is well known, even small alteration of solar activity influent essential upon the biological and ecological balance at the Earth for all levels- from viruses and micro-organisms to biological societies and ecological systems at all. The most bright indicator of the solar activity alteration are changes of the pathogenic organisms activity as a result of a displacement of biological equilibrium. But the other phenomena, which are not connected with pathogenic biological objects are very important for thelife on the Earth and ecological balance too, although they can not be so obviously observed.

Dr. Alexander Luchinskiy A; Prof Dr; Yakov S. Shifrin

2001-01-01T23:59:59.000Z

213

RELAP5 MODEL OF THE DIVERTOR PRIMARY HEAT TRANSFER SYSTEM  

SciTech Connect

This report describes the RELAP5 model that has been developed for the divertor primary heat transfer system (PHTS). The model is intended to be used to examine the transient performance of the divertor PHTS and evaluate control schemes necessary to maintain parameters within acceptable limits during transients. Some preliminary results are presented to show the maturity of the model and examine general divertor PHTS transient behavior. The model can be used as a starting point for developing transient modeling capability, including control system modeling, safety evaluations, etc., and is not intended to represent the final divertor PHTS design. Preliminary calculations using the models indicate that during normal pulsed operation, present pressurizer controls may not be sufficient to keep system pressures within their desired range. Additional divertor PHTS and control system design efforts may be required to ensure system pressure fluctuation during normal operation remains within specified limits.

Popov, Emilian L [ORNL; Yoder Jr, Graydon L [ORNL; Kim, Seokho H [ORNL

2010-08-01T23:59:59.000Z

214

A Beta Regression Model for Improved Solar Radiation Predictions  

Science Conference Proceedings (OSTI)

Predicting global solar radiation is an integral part of much environmental modeling. There are several approaches for predicting global solar radiation at a site where no instrumentation exists. One popular approach uses the difference between ...

Randall Mullen; Lucy Marshall; Brian McGlynn

2013-08-01T23:59:59.000Z

215

A beta regression model for improved solar radiation predictions  

Science Conference Proceedings (OSTI)

Predicting global solar radiation is an integral part of much environmental modeling. There are several approaches for predicting global solar radiation at a site where no instrumentation exists. One popular approach uses the difference between ...

Randall Mullen; Lucy Marshall; Brian McGlynn

216

An Accurate and Efficient Radiation Algorithm for Middle Atmosphere Models  

Science Conference Proceedings (OSTI)

An accurate, efficient, and user-friendly radiation algorithm is developed for calculating net radiative heating rate in middle atmosphere models. The Curtis matrix interpolation scheme originally developed by Zhu is adopted with explicit ...

Xun Zhu

1994-12-01T23:59:59.000Z

217

Measurement and Modeling Implications of Transfer and Transformation  

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

Measurement and Modeling Implications of Transfer and Transformation Measurement and Modeling Implications of Transfer and Transformation Processes at the Plant/Air Interface Speaker(s): Randy Maddalena Date: October 13, 1998 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Richard Sextro To understand the chemodynamic role of vegetation in a multimedia system, the rate and extent of chemical partitioning from adjacent environmental media and the rate of chemical transformation associated with vegetation need to be determined. An exposure system was used to isolate and expose above ground vegetation to semi-volatile air contaminants. Measurements of phenanthrene, anthracene, fluoranthene and pyrene in the chamber air and the plant tissue were collected during both the uptake and clearance phase of exposure events. The measurements were fitted to the mass balance of the

218

Thermodynamics of enhanced heat transfer: a model study  

E-Print Network (OSTI)

Situations where a spontaneous process of energy or matter transfer is enhanced by an external device are widespread in nature (human sweating system, enzyme catalysis, facilitated diffusion across bio-membranes, industrial heat exchangers). The thermodynamics of such processes remains however open. Here we study enhanced heat transfer by a model junction immersed between two thermal baths at different temperatures $T_h$ and $T_c$ ($T_h>T_c$). The transferred heat power is enhanced via controlling the junction by means of external time-dependent fields. Provided that the spontaneous heat flow process is optimized over the junction Hamiltonian, any enhancement of this spontaneous process does demand consumption and subsequent dissipation of work. The efficiency of enhancement is defined via the increment in the heat power divided over the amount of consumed work. We show that this efficiency is bounded from above by $T_c/(T_h-T_c)$. Formally this is identical to the Carnot bound for the efficiency of ordinary refrigerators which transfer heat from cold to hot. It also shares some (but not all) physical features of the Carnot bound.

Karen Hovhannisyan; Armen E. Allahverdyan

2010-07-20T23:59:59.000Z

219

Modelling charge transfer reactions with the frozen density embedding formalism  

SciTech Connect

The frozen density embedding (FDE) subsystem formulation of density-functional theory is a useful tool for studying charge transfer reactions. In this work charge-localized, diabatic states are generated directly with FDE and used to calculate electronic couplings of hole transfer reactions in two {pi}-stacked nucleobase dimers of B-DNA: 5{sup '}-GG-3{sup '} and 5{sup '}-GT-3{sup '}. The calculations rely on two assumptions: the two-state model, and a small differential overlap between donor and acceptor subsystem densities. The resulting electronic couplings agree well with benchmark values for those exchange-correlation functionals that contain a high percentage of exact exchange. Instead, when semilocal GGA functionals are used the electronic couplings are grossly overestimated.

Pavanello, Michele [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Neugebauer, Johannes [Institute for Physical and Theoretical Chemistry, Technische Universitaet Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig (Germany)

2011-12-21T23:59:59.000Z

220

Radiative transfer in plane-parallel media and Cauchy integral equations III. The finite case  

E-Print Network (OSTI)

We come back to the Cauchy integral equations occurring in radiative transfer problems posed in finite, plane-parallel media with light scattering taken as monochromatic and isotropic. Their solution is calculated following the classical scheme where a Cauchy integral equation is reduced to a couple of Fredholm integral equations. It is expressed in terms of two auxiliary functions $\\zeta_+$ and $\\zeta_-$ we introduce in this paper. These functions show remarkable analytical properties in the complex plane. They satisfy a simple algebraic relation which generalizes the factorization relation of semi-infinite media. They are regular in the domain of the Fredholm integral equations they satisfy, and thus can be computed accurately. As an illustration, the X- and Y-functions are calculated in the whole complex plane, together with the extension in this plane of the so-called Sobouti's functions.

B. Rutily; L. Chevallier; J. Bergeat

2006-01-16T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Polarized radiance fields under a dynamic ocean surface: a three-dimensional radiative transfer solution  

Science Conference Proceedings (OSTI)

The hybrid matrix operator, Monte Carlo (HMOMC) method previously reported [Appl. Opt.47, 1063-1071 (2008)APOPAI0003-693510.1364/AO.47.001063] is improved by neglecting higher-order terms in the coupling of the matrix operators and by introducing a dual grid scheme. The computational efficiency for solving the vector radiative transfer equation in a full 3D coupled atmosphere-surface-ocean system is substantially improved, and, thus, large-scale simulations of the radiance distribution become feasible. The improved method is applied to the computation of the polarized radiance field under realistic surface waves simulated by the power spectral density method. To the authors' best knowledge, this is the first time that the polarized radiance field under a dynamic ocean surface and the underwater image of an object above such an ocean surface have been reported.

You Yu; Zhai Pengwang; Kattawar, George W.; Yang Ping

2009-06-01T23:59:59.000Z

222

A study of longwave radiation codes for climate studies: Validation with ARM observations and tests in general circulation models. Final report, September 15, 1990--October 31, 1994  

SciTech Connect

DOE has launched a major initiative -- the Atmospheric Radiation Measurements (ARM) Program -- directed at improving the parameterization of the physics governing cloud and radiative processes in general circulation models (GCMs). One specific goal of ARM is to improve the treatment of radiative transfer in GCMs under clear-sky, general overcast and broken cloud conditions. In 1990, the authors proposed to contribute to this goal by attacking major problems connected with one of the dominant radiation components of the problem -- longwave radiation. In particular, their long-term research goals are to: develop an optimum longwave radiation model for use in GCMs that has been calibrated with state-of-the-art observations, assess the impact of the longwave radiative forcing in a GCM, determine the sensitivity of a GCM to the radiative model used in it, and determine how the longwave radiative forcing contributes relatively when compared to shortwave radiative forcing, sensible heating, thermal advection and expansion.

Ellingson, R.G.; Baer, F.

1998-09-01T23:59:59.000Z

223

Crude Oil Price Forecasting: A Transfer Learning Based Analog Complexing Model  

Science Conference Proceedings (OSTI)

Most of the existing models for oil price forecasting only use the data in the forecasted time series itself. This study proposes a transfer learning based analog complexing model (TLAC). It first transfers some related time series in source domain to ... Keywords: transfer learning method, analog complexing model, genetic algorithm, crude oil price forecasting

Jin Xiao; Changzheng He; Shouyang Wang

2012-08-01T23:59:59.000Z

224

Development of Aerosol Models for Radiative Flux Calculations at ARM Sites: Utility of Trajectory Clustering for Characterizing Aerosol Climatology  

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

Development of Aerosol Models for Radiative Flux Development of Aerosol Models for Radiative Flux Calculations at ARM Sites: Utility of Trajectory Clustering for Characterizing Aerosol Climatology E. Andrews Cooperative Institute for Research in the Environment University of Colorado Boulder, Colorado E. Andrews, J. A. Ogren, P. J. Sheridan, and J. M. Harris Climate Monitoring and Diagnostics Laboratory National Oceanic and Atmospheric Administration Boulder, Colorado P. K. Quinn Pacific Marine Environmental Laboratory National Oceanic and Atmospheric Administration Seattle, Washington Abstract The uncertainties associated with assumptions of generic aerosol properties in radiative transfer codes are unknown, which means that these uncertainties are frequently invoked when models and

225

Modeling Ultraviolet Radiation at the Earth's Surface. Part II: Model and Instrument Comparison  

Science Conference Proceedings (OSTI)

High-resolution measurements in the spectral region of 280?400 nm using a double monochromator are compared with detailed radiative transfer calculations at Reading, United Kingdom (52N, 0), for clear and totally overcast days, using aerosol ...

Piers M. De F. Forster; Keith P. Shine; Ann R. Webb

1995-11-01T23:59:59.000Z

226

Modeling of Heat Transfer in Geothermal Heat Exchangers  

E-Print Network (OSTI)

Ground-coupled heat pump (GCHP) systems have been gaining increasing popularity for space conditioning in residential and commercial buildings. The geothermal heat exchanger (GHE) is devised for extraction or injection of thermal energy from/into the ground. This paper summarizes the authors' studies on heat transfer in ground-coupled heat pump systems. Taking the fluid axial convective heat transfer and thermal short-circuiting among U-tube legs into account, a quasi-3-D model has been solved for heat transfer inside boreholes. The transient 2-D temperature response in a semi-infinite medium with a line-source of finite length has also been derived for heat conduction outside boreholes. In order to investigate the impact of groundwater advection on the performance of ground heat exchangers, an analytical solution is obtained for a line heat source in an infinite porous medium with groundwater advection. These explicit expressions have more solid theoretical basis, and can be easily incorporated into computer programs for thermal analysis and engineering design of ground heat exchangers.

Cui, P.; Man, Y.; Fang, Z.

2006-01-01T23:59:59.000Z

227

Thermodynamics of enhanced heat transfer: a model study  

E-Print Network (OSTI)

Situations where a spontaneous process of energy or matter transfer is enhanced by an external device are widespread in nature (human sweating system, enzyme catalysis, facilitated diffusion across bio-membranes, industrial heat exchangers). The thermodynamics of such processes remains however open. Here we study enhanced heat transfer by a model junction immersed between two thermal baths at different temperatures $T_h$ and $T_c$ ($T_h>T_c$). The transferred heat power is enhanced via controlling the junction by means of external time-dependent fields. Provided that the spontaneous heat flow process is optimized over the junction Hamiltonian, any enhancement of this spontaneous process does demand consumption and subsequent dissipation of work. The efficiency of enhancement is defined via the increment in the heat power divided over the amount of consumed work. We show that this efficiency is bounded from above by $T_c/(T_h-T_c)$. Formally this is identical to the Carnot bound for the efficiency of ordinary ...

Hovhannisyan, Karen; 10.1088/1742-5468/2010/06/P06010

2010-01-01T23:59:59.000Z

228

Simulation of Static Flying Attitudes with Different Heat Transfer Models for a Flying-Height Control Slider with Thermal Protrusion  

E-Print Network (OSTI)

Zhang, S. , Bogy, D.B. : A heat transfer model for thermal ?A phenomenological heat transfer model for the molecular gasWong, C.H. : A generalized heat transfer model for thin ?lm

Chen, Du; Bogy, David B.

2010-01-01T23:59:59.000Z

229

Pioneering remote sensing in the USSR. 1. Radiation transfer in the optical wavelength region of the electromagnetic spectrum  

Science Conference Proceedings (OSTI)

In this paper a review is presented of the pioneering space research carried out under the leadership of Professor K. Ya. Kondratyev and with his direct participation. Some of his work concerned with radiation transfer in the atmosphere and with remote ...

T. A. Sushkevich

2008-05-01T23:59:59.000Z

230

A Reduced Radiation Grid for the ECMWF Integrated Forecasting System  

Science Conference Proceedings (OSTI)

A specific interface between the radiation transfer calculations and the rest of the ECMWF model was introduced in 2003, potentially providing substantial economy in computer time by reducing the spatial resolution at which radiation transfer is ...

Jean-Jacques Morcrette; George Mozdzynski; Martin Leutbecher

2008-12-01T23:59:59.000Z

231

Electromagnetic field radiation model for lightning strokes to tall structures  

SciTech Connect

This paper describes observation and analysis of electromagnetic field radiation from lightning strokes to tall structures. Electromagnetic field waveforms and current waveforms of lightning strokes to the CN Tower have been simultaneously measured since 1991. A new calculation model of electromagnetic field radiation is proposed. The proposed model consists of the lightning current propagation and distribution model and the electromagnetic field radiation model. Electromagnetic fields calculated by the proposed model, based on the observed lightning current at the CN Tower, agree well with the observed fields at 2km north of the tower.

Motoyama, H. [CRIEPI, Tokyo (Japan); Janischewskyj, W.; Hussein, A.M. [Univ. of Toronto, Ontario (Canada); Chisholm, W.A. [Ontario Hydro Technologies, Toronto, Ontario (Canada); Chang, J.S. [McMaster Univ., Hamilton, Ontario (Canada); Rusan, R.

1996-07-01T23:59:59.000Z

232

Antarctic Clouds and Radiation within the NCAR Climate Models  

Science Conference Proceedings (OSTI)

To evaluate and improve the treatment of clouds and radiation by the climate models of the National Center for Atmospheric Research (NCAR), simulations by the NCAR Community Climate Model version 3 (CCM3), as well as the recently released ...

Keith M. Hines; David H. Bromwich; Philip J. Rasch; Michael J. Iacono

2004-03-01T23:59:59.000Z

233

A Parametric Radiative Forcing Model for Contrail Cirrus  

Science Conference Proceedings (OSTI)

A new parameterized analytical model is presented to compute the instantaneous radiative forcing (RF) at the top of the atmosphere (TOA) produced by an additional thin contrail cirrus layer (called contrail below). The model calculates the RF ...

U. Schumann; B. Mayer; K. Graf; H. Mannstein

2012-07-01T23:59:59.000Z

234

A transfer model using a typed feature structure rewriting system with inheritance  

Science Conference Proceedings (OSTI)

We propose a model for transfer in machine translation which uses a rewriting system for typed feature structures. The grammar definitions describe transfer relations which are applied on the input structure (a typed feature structure) by the ...

Rmi Zajac

1989-06-01T23:59:59.000Z

235

Modeling Topographic Solar Radiation Using GOES Data  

Science Conference Proceedings (OSTI)

In this paper the authors present an algorithm that combines solar radiation fields derived from Geostationary Operational Environmental Satellite (GOES) observations with digital elevation data to produce topographically varying insolation ...

R. Dubayah; S. Loechel

1997-02-01T23:59:59.000Z

236

A study of longwave radiation codes for climate studies: Validation with ARM observations and tests in general circulation models  

SciTech Connect

Research by the US Department of Energy (DOE) has shown that cloud radiative feedback is the single most important effect determining the magnitude of possible climatic responses to human activity. However, these effects are still not known at the levels needed for climate prediction. Consequently, DOE has launched a major initiative-- the Atmospheric Radiation Measurements (ARM) Program -- directed at improving the parameterization of the physics governing cloud and radiative processes in general circulation models (GCM's). One specific goal of ARM is to improve the treatment of radiative transfer in GCM's under clear-sky, general overcast and broken cloud conditions. Our approach to developing the radiation model will be to test existing models in an iterative, predictive fashion. We will supply the Clouds and Radiative Testbed (CART) with a set of models to be compared with operationally observed data. The differences we find will lead to the development of new models to be tested with new data. Similarly, our GCM studies will use existing GCM's to study the radiation sensitivity problem. We anticipate that the outcome of this approach will provide both a better longwave radiative forcing algorithm and a better understanding of how longwave radiative forcing influences the equilibrium climate of the atmosphere.

Ellingson, R.G.; Baer, F.

1992-01-01T23:59:59.000Z

237

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

or chemical species in a multiphase porous medium system canand radiation in a multiphase, multicomponent, porous mediummultiphase flow, multicomponent transport, and heat transfer in porous

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

238

Modelling magnetically dominated and radiatively cooling jets  

E-Print Network (OSTI)

Using 3D-MHD Eulerian-grid numerical simulations, we study the formation and evolution of rising magnetic towers propagating into an ambient medium. The towers are generated from a localized injection of pure magnetic energy. No rotation is imposed on the plasma. We compare the evolution of a radiatively cooling tower with an adiabatic one, and find that both bend due to pinch instabilities. Collimation is stronger in the radiative cooling case; the adiabatic tower tends to expand radially. Structural similarities are found between these towers and the millimeter scale magnetic towers produced in laboratory experiments.

Huarte-Espinosa, Martin; Blackman, Eric

2010-01-01T23:59:59.000Z

239

A Surface Solar Radiation Model for Cloudy Atmospheres  

Science Conference Proceedings (OSTI)

A numerical solar radiation model based on standard meteorological data was revised for clouds using data from the GARP Atlantic Tropical Experiment (GATE). Climatic-mean transmittance functions were revised for low and convective clouds ...

Marshall A. Atwater; John T. Ball

1981-04-01T23:59:59.000Z

240

[Treatment of cloud radiative effects in general circulation models  

SciTech Connect

This is a renewal proposal for an on-going project of the Department of Energy (DOE)/Atmospheric Radiation Measurement (ARM) Program. The objective of the ARM Program is to improve the treatment of radiation-cloud in GCMs so that reliable predictions of the timing and magnitude of greenhouse gas-induced global warming and regional responses can be made. The ARM Program supports two research areas: (I) The modeling and analysis of data related to the parameterization of clouds and radiation in general circulation models (GCMs); and (II) the development of advanced instrumentation for both mapping the three-dimensional structure of the atmosphere and high accuracy/precision radiometric observations. The present project conducts research in area (I) and focuses on GCM treatment of cloud life cycle, optical properties, and vertical overlapping. The project has two tasks: (1) Development and Refinement of GCM Radiation-Cloud Treatment Using ARM Data; and (2) Validation of GCM Radiation-Cloud Treatment.

Wang, W.C.

1993-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Heat transfer through porous multiphase systems measurement, modelling and applications in printing of coated papers.  

E-Print Network (OSTI)

??This work examines the thermal transfer through porous media by means of measurement of the effective thermal conductivity and modelling of the structural parameters. While (more)

Gerstner, Philip

2010-01-01T23:59:59.000Z

242

Modelling of mass transfer during wood fermentation processes to produce bioalcohol.  

E-Print Network (OSTI)

??The aim of this work is to model the bioethanol production by wood degradation, and to check if there is mass transfer limitations in the (more)

Spalluto, Giorgio

2011-01-01T23:59:59.000Z

243

Application Of A Spherical-Radial Heat Transfer Model To Calculate...  

Open Energy Info (EERE)

Application Of A Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal...

244

Modeling of Heat Transfer during Cooling of a Hot Steel Plate  

Science Conference Proceedings (OSTI)

Thus, it is crucial to develop accurate heat transfer models in order to predict the temperature history during cooling of steel plates. The present study describes a ...

245

Modelling Heat Transfer in Nanofluids Based on Coupled MD ...  

Science Conference Proceedings (OSTI)

Simulations have shown that the additional heat transfer caused by the collision of the nanoparticles with the heat source contributes significantly to the...

246

Solar radiation data modeling with a novel surface fitting approach  

E-Print Network (OSTI)

Abstract. In this work one year hourly solar radiation data are analyzed and modeled. Using a 2-D surface fitting approach, a novel model is developed for the general behavior of the solar radiation. The mathematical formulation of the 2-D surface model is obtained. The accuracy of the analytical surface model is tested and compared with another surface model obtained from a feed-forward Neural Network(NN). Analytical surface model and NN surface model are compared in the sense of Root Mean Square Error (RMSE). It is obtained that the NN surface model gives more accurate results with smaller RMSE results. However, unlike the specifity of the NN surface model, the analytical surface model provides an intuitive and more generalized form that can be suitable for several other locations on earth. 1

F. Onur Hocaoglu; mer Nezih Gerek; Mehmet Kurban

2007-01-01T23:59:59.000Z

247

Vertical Profiles of Aerosol and Radiation and the Influence of a Temperature Inversion: Measurements and Radiative Transfer Calculations  

Science Conference Proceedings (OSTI)

The results of an airborne experiment performed near Mnchengladbach (Germany) in November 1993 are reported. Besides meteorological data, vertical profiles of aerosol properties (number concentration, size distribution) and radiation (...

M. Wendisch; S. Mertes; A. Ruggaber; T. Nakajima

1996-10-01T23:59:59.000Z

248

Radiation transport phenomena and modeling - part A: Codes  

Science Conference Proceedings (OSTI)

The need to understand how particle radiation (high-energy photons and electrons) from a variety of sources affects materials and electronics has motivated the development of sophisticated computer codes that describe how radiation with energies from 1.0 keV to 100.0 GeV propagates through matter. Predicting radiation transport is the necessary first step in predicting radiation effects. The radiation transport codes that are described here are general-purpose codes capable of analyzing a variety of radiation environments including those produced by nuclear weapons (x-rays, gamma rays, and neutrons), by sources in space (electrons and ions) and by accelerators (x-rays, gamma rays, and electrons). Applications of these codes include the study of radiation effects on electronics, nuclear medicine (imaging and cancer treatment), and industrial processes (food disinfestation, waste sterilization, manufacturing.) The primary focus will be on coupled electron-photon transport codes, with some brief discussion of proton transport. These codes model a radiation cascade in which electrons produce photons and vice versa. This coupling between particles of different types is important for radiation effects. For instance, in an x-ray environment, electrons are produced that drive the response in electronics. In an electron environment, dose due to bremsstrahlung photons can be significant once the source electrons have been stopped.

Lorence, L.J.

1997-06-01T23:59:59.000Z

249

Heat Transfer Analysis and Modeling of a Parabolic Trough Solar Receiver Implemented in Engineering Equation Solver  

DOE Green Energy (OSTI)

This report describes the development, validation, and use of a heat transfer model implemented in Engineering Equation Solver. The model determines the performance of a parabolic trough solar collector's linear receiver, also called a heat collector element. All heat transfer and thermodynamic equations, optical properties, and parameters used in the model are discussed. The modeling assumptions and limitations are also discussed, along with recommendations for model improvement.

Forristall, R.

2003-10-01T23:59:59.000Z

250

Center for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat Transfer and Fluid3D Model of Heat Transfer and Fluid  

E-Print Network (OSTI)

Center for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat Transfer and Fluid WindowModeling a 3D Window Future WorkFuture Work #12;Center for Energy Efficiency and Renewable Energy

Massachusetts at Amherst, University of

251

Hawking radiation via Landauer transport model  

E-Print Network (OSTI)

Recently, Nation et al confirmed that fluxes of Hawking radiation energy and entropy from a black hole can be regarded as a one-dimensional (1D) Landauer transport process. Their work can be extended to background spacetimes with gauge potential. The result shows that the energy flux, which is indicated to be equal to the energy-momentum tensor flux, contains not only the contribution of thermal flux but also that of particle flux. We find that the charge can also be regarded as transporting via a 1D quantum channel and the charge flux is equal to the gauge flux.

Xiao-Xiong Zeng; Wen-Biao Liu

2011-06-03T23:59:59.000Z

252

Hierarchical fusion of expert opinions in the Transferable Belief Model, application to climate sensitivity  

Science Conference Proceedings (OSTI)

This paper examines the fusion of conflicting and not independent expert opinion in the Transferable Belief Model. A hierarchical fusion procedure based on the partition of experts into schools of thought is introduced, justified by the sociology of ... Keywords: Climate sensitivity, Expert aggregation, Information fusion, Transferable Belief Model

Minh Ha-Duong

2008-11-01T23:59:59.000Z

253

Effects of Radiation on Adaptive Immunity: Contact Hypersensitivity Model  

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

Radiation on Adaptive Immunity: Contact Hypersensitivity Model Radiation on Adaptive Immunity: Contact Hypersensitivity Model Gregory Nelson Loma Linda University Abstract It has long been appreciated that cells of the immune system are radiosensitive and use apoptosis as the primary mechanism of cell death following injury. The hypervariability of the immunoglobulin superfamily of genes expressed in lymphoid cells also led to the appreciation of the nonhomologous end joining mechanism of DNA repair. Clinically, whole body irradiation is used in treatment of some lymphomas and as an immunosuppressive agent for bone marrow transplants. Inflammation at sites of radiotherapy is a common side effect. Many studies with radiation have addressed the changes in cell populations following radiation exposure and have shown a reproducible pattern of relative sensitivities amongst

254

Numerical study on transient heat transfer under soil with plastic mulch in agriculture applications using a nonlinear finite element model  

E-Print Network (OSTI)

In this paper is developed a simple mathematical model of transient heat transfer under soil with plastic mulch in order to determine with numerical studies the influence of different plastic mulches on the soil temperature and the evolutions of temperatures at different depths with time. The governing differential equations are solved by a Galerkin Finite Element Model, taking into account the nonlinearities due to radiative heat exchange between the soil surface, the plastic mulch and the atmosphere. The model was validated experimentally giving good approximation of the model to the measured data. Simulations were run with the validated model in order to determine the optimal combination of mulch optical properties to maximize the soil temperature with a Taguchi's analysis, proving that the material most used nowadays in Colombia is not the optimal and giving quantitative results of the properties the optimal mulch must possess.

De Castro, Carlos Armando

2011-01-01T23:59:59.000Z

255

Radiation Fog: A Comparison of Model Simulation with Detailed Observations  

Science Conference Proceedings (OSTI)

A one-dimensional model designed to study the formation, growth, and dissipation of radiation fog is described. The model is compared with detailed observations made at the 200-m tower at Cabauw in the Netherlands. This study we use observations ...

Peter G. Duynkerke

1991-02-01T23:59:59.000Z

256

Advantages of a Topographically Controlled Runoff Simulation in a SoilVegetationAtmosphere Transfer Model  

Science Conference Proceedings (OSTI)

Two methods to incorporate subgrid variability in soil moisture and runoff production into soilvegetationatmosphere transfer (SVAT) models are compared: 1) the variable infiltration capacity model approach (VIC), and 2) a modified TOPMODEL ...

Kirsten Warrach; Marc Stieglitz; Heinz-Theo Mengelkamp; Ehrhard Raschke

2002-04-01T23:59:59.000Z

257

Radiative Effects of Cloud-Type Variations  

Science Conference Proceedings (OSTI)

Radiative flux changes induced by the occurrence of different cloud types are investigated using International Satellite Cloud Climatology Project cloud data and a refined radiative transfer model from National Aeronautics and Space ...

Ting Chen; William B. Rossow; Yuanchong Zhang

2000-01-01T23:59:59.000Z

258

Parameterization of Outgoing Infrared Radiation Derived from Detailed Radiative Calculations  

Science Conference Proceedings (OSTI)

State-of-the-art radiative transfer models can calculate outgoing infrared (IR) irradiance at the top of the atmosphere (F) to an accuracy suitable for climate modeling given the proper atmospheric profiles of temperature and absorbing gases and ...

Starley L. Thompson; Stephen G. Warren

1982-12-01T23:59:59.000Z

259

Brazil Global Horizontal Solar Radiation Model (40km) from INPE | OpenEI  

Open Energy Info (EERE)

40km) from INPE 40km) from INPE Dataset Summary Description (Abstract): Global horizontal solar radiation in kWh/m2/day for 1 year organized into cells with 40km x 40km (Purpose): To provide a set of consistent, reliable, verifiable, and accessible global data sets for international and in-country investors and other stakeholders (Supplemental Information): The BRASIL-SR model and the SPRING software (both developed by INPE - National Institute for Space Research) were used to produce the dataset and SHAPE files. The assessment of reliability levels of the BRASIL-SR model were performed through the evaluation of the deviations shown by the estimated values for solar radiation flux vis-à-vis the values measured at the surface (ground truth). This evaluation was done in two phases. The first phase consisted in an inter-comparison between the core radiation transfer models adopted by the SWERA Project to map the solar energy in the various countries participating in the project. The HELIOSAT model took art in this phase like benchmark due to its employment to map solar energy resources in countries from European Union. In the second phase, the solar flux estimates provided by the BRASIL-SR model were compared with measured values acquired at several solarimetric stations spread along the Brazilian territory.

260

Brazil PAR Solar Radiation Model (40km) from INPE and LABSOLAR | OpenEI  

Open Energy Info (EERE)

40km) from INPE and LABSOLAR 40km) from INPE and LABSOLAR Dataset Summary Description (Abstract): Photosynthetically active radiation in kWh/m2/day for 1 year organized into cells with 40km x 40km (Purpose): The BRASIL-SR model and the SPRING software (both developed by INPE - National Institute for Space Research) were used to produce the dataset and SHAPE files (Supplemental Information): The assessment of reliability levels of the BRASIL-SR model were performed through the evaluation of the deviations shown by the estimated values for solar radiation flux vis-à-vis the values measured at the surface (ground truth). This evaluation was done in two phases. The first phase consisted in an inter-comparison between the core radiation transfer models adopted by the SWERA Project to map the solar energy in the various countries participating in the project. The HELIOSAT model took part in this phase like benchmark due to its employment to map solar energy resources in countries from European Union. In the second phase, the solar flux estimates provided by the BRASIL-SR model were compared with measured values acquired at several solarimetric stations spread along the Brazilian territory

Note: This page contains sample records for the topic "radiation transfer models" 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

Brazil Direct Normal Solar Radiation Model (40km) from INPE and LABSOLAR |  

Open Energy Info (EERE)

40km) from INPE and LABSOLAR 40km) from INPE and LABSOLAR Dataset Summary Description (Abstract): Normal direct solar radiation in kWh/m2/day for 1 year organized into cells with 40km x 40km (Purpose): To provide a set of consistent, reliable, verifiable, and accessible global data sets for international and in-country investors and other stakeholders (Supplemental Information): The BRASIL-SR model and the SPRING software (both developed by INPE - National Institute for Space Research) were used to produce the dataset and SHAPE files. The assessment of reliability levels of the BRASIL-SR model were performed through the evaluation of the deviations shown by the estimated values for solar radiation flux vis-à-vis the values measured at the surface (ground truth). This evaluation was done in two phases. The first phase consisted in an inter-comparison between the core radiation transfer models adopted by the SWERA Project to map the solar energy in the various countries participating in the project. The HELIOSAT model took part in this phase like benchmark due to its employment to map solar energy resources in countries from European Union. In the second phase, the solar flux estimates provided by the BRASIL-SR model were compared with measured values acquired at several solarimetric stations spread along the Brazilian territory.

262

Brazil Direct Normal Solar Radiation Model (10km) from INPE and LABSOLAR |  

Open Energy Info (EERE)

10km) from INPE and LABSOLAR 10km) from INPE and LABSOLAR Dataset Summary Description (Abstract): Normal direct solar radiation in kWh/m2/day for 1 year organized into cells with 10km x 10km (Purpose): The BRASIL-SR model and the SPRING software (both developed by INPE - National Institute for Space Research) were used to produce the dataset and SHAPE files (Supplemental Information): The assessment of reliability levels of the BRASIL-SR model were performed through the evaluation of the deviations shown by the estimated values for solar radiation flux vis-à-vis the values measured at the surface (ground truth). This evaluation was done in two phases. The first phase consisted in an inter-comparison between the core radiation transfer models adopted by the SWERA Project to map the solar energy in the various countries participating in the project. The HELIOSAT model took part in this phase like benchmark due to its employment to map solar energy resources in countries from European Union. In the second phase, the solar flux estimates provided by the BRASIL-SR model were compared with measured values acquired at several solarimetric stations spread along the Brazilian territory

263

Brazil Global Horizontal Solar Radiation Model (10km) from INPE | OpenEI  

Open Energy Info (EERE)

10km) from INPE 10km) from INPE Dataset Summary Description (Abstract): Global horizontal solar radiation in kWh/m2/day for 1 year organized into cells with 10km x 10km (Purpose): The BRASIL-SR model and the SPRING software (both developed by INPE - National Institute for Space Research) were used to produce the dataset and SHAPE files (Supplemental Information): The assessment of reliability levels of the BRASIL-SR model were performed through the evaluation of the deviations shown by the estimated values for solar radiation flux vis-à-vis the values measured at the surface (ground truth). This evaluation was done in two phases. The first phase consisted in an inter-comparison between the core radiation transfer models adopted by the SWERA Project to map the solar energy in the various countries participating in the project. The HELIOSAT model took part in this phase like benchmark due to its employment to map solar energy resources in countries from European Union. In the second phase, the solar flux estimates provided by the BRASIL-SR model were compared with measured values acquired at several solarimetric stations spread along the Brazilian territory

264

Brazil PAR Solar Radiation Model (10km) from INPE and LABSOLAR | OpenEI  

Open Energy Info (EERE)

10km) from INPE and LABSOLAR 10km) from INPE and LABSOLAR Dataset Summary Description (Abstract): Photosynthetically active radiation in kWh/m2/day for 1 year organized into cells with 10km x 10km (Purpose): The BRASIL-SR model and the SPRING software (both developed by INPE -National Institute for Space Research) were used to produce the dataset and SHAPE files (Supplemental Information): The assessment of reliability levels of the BRASIL-SR model were performed through the evaluation of the deviations shown by the estimated values for solar radiation flux vis-à-vis the values measured at the surface (ground truth). This evaluation was done in two phases. The first phase consisted in an inter-comparison between the core radiation transfer models adopted by the SWERA Project to map the solar energy in the various countries participating in the project. The HELIOSAT model took part in this phase like benchmark due to its employment to map solar energy resources in countries from European Union. In the second phase, the solar flux estimates provided by the BRASIL-SR model were compared with measured values acquired at several solarimetric stations spread along the Brazilian territory

265

Brazil Latitude Tilted Solar Radiation Model (10km) from INPE and LABSOLAR  

Open Energy Info (EERE)

10km) from INPE and LABSOLAR 10km) from INPE and LABSOLAR Dataset Summary Description (Abstract): Latitude tilted solar radiation in kWh/m2/day for 1 year organized into cells with 10km x 10km (Purpose): The BRASIL-SR model and the SPRING software (both developed by INPE -National Institute for Space Research) were used to produce the dataset and SHAPE files (Supplemental Information): The assessment of reliability levels of the BRASIL-SR model were performed through the evaluation of the deviations shown by the estimated values for solar radiation flux vis-à-vis the values measured at the surface (ground truth). This evaluation was done in two phases. The first phase consisted in an inter-comparison between the core radiation transfer models adopted by the SWERA Project to map the solar energy in the various countries participating in the project. The HELIOSAT model took part in this phase like benchmark due to its employment to map solar energy resources incountries from European Union. In the second phase, the solar flux estimates providedby the BRASIL-SR model were compared with measured values acquired at several solarimetric stations spread along the Brazilian territory

266

A Computational Model of Cellular Response to Modulated Radiation Fields  

Science Conference Proceedings (OSTI)

Purpose: To develop a model to describe the response of cell populations to spatially modulated radiation exposures of relevance to advanced radiotherapies. Materials and Methods: A Monte Carlo model of cellular radiation response was developed. This model incorporated damage from both direct radiation and intercellular communication including bystander signaling. The predictions of this model were compared to previously measured survival curves for a normal human fibroblast line (AGO1522) and prostate tumor cells (DU145) exposed to spatially modulated fields. Results: The model was found to be able to accurately reproduce cell survival both in populations which were directly exposed to radiation and those which were outside the primary treatment field. The model predicts that the bystander effect makes a significant contribution to cell killing even in uniformly irradiated cells. The bystander effect contribution varies strongly with dose, falling from a high of 80% at low doses to 25% and 50% at 4 Gy for AGO1522 and DU145 cells, respectively. This was verified using the inducible nitric oxide synthase inhibitor aminoguanidine to inhibit the bystander effect in cells exposed to different doses, which showed significantly larger reductions in cell killing at lower doses. Conclusions: The model presented in this work accurately reproduces cell survival following modulated radiation exposures, both in and out of the primary treatment field, by incorporating a bystander component. In addition, the model suggests that the bystander effect is responsible for a significant portion of cell killing in uniformly irradiated cells, 50% and 70% at doses of 2 Gy in AGO1522 and DU145 cells, respectively. This description is a significant departure from accepted radiobiological models and may have a significant impact on optimization of treatment planning approaches if proven to be applicable in vivo.

McMahon, Stephen J., E-mail: stephen.mcmahon@qub.ac.uk [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); Butterworth, Karl T. [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom)] [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); McGarry, Conor K. [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom) [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Northern Ireland (United Kingdom); Trainor, Colman [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom)] [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); O'Sullivan, Joe M. [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom) [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); Clinical Oncology, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Belfast, Northern Ireland (United Kingdom); Hounsell, Alan R. [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom) [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Northern Ireland (United Kingdom); Prise, Kevin M. [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom)] [Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom)

2012-09-01T23:59:59.000Z

267

Radiation Boundary Conditions in Numerical Modeling  

Science Conference Proceedings (OSTI)

A two-dimensional anelastic model is used to study the propagation of errors arising from the use of open lateral boundaries. Reference experiments were performed using very large horizontal domains. Other experiments were carried out in smaller ...

Mark Hedley; M. K. Yau

1988-09-01T23:59:59.000Z

268

Modeling of data center airflow and heat transfer: State of the art and future trends  

Science Conference Proceedings (OSTI)

An assessment of the current thermal modeling methodologies for data centers is presented, with focus on the use of computational fluid dynamics and heat transfer as analysis tools, and model validation. Future trends in reduced or compact modeling of ... Keywords: Data center, Reduced order models, Thermal modeling

Jeffrey Rambo; Yogendra Joshi

2007-06-01T23:59:59.000Z

269

Two-fluid matter-quintessence FLRW models: energy transfer and the equation of state of the universe  

E-Print Network (OSTI)

Recent observations support the view that the universe is described by a FLRW model with $\\Omega_m^0 \\approx 0.3$, $\\Omega_{\\Lambda}^0 \\approx 0.7$, and $w \\leq -1/3$ at the present epoch. There are several theoretical suggestions for the cosmological $\\Lambda$ component and for the particular form of the energy transfer between this dark energy and matter. This gives a strong motive for a systematic study of general properties of two-fluid FLRW models. We consider a combination of one perfect fluid, which is quintessence with negative pressure ($p_Q = w\\epsilon_Q$), and another perfect fluid, which is a mixture of radiation and/or matter components with positive pressure ($p = \\beta \\epsilon_m$), which define the associated one-fluid model ($p = \\gamma \\epsilon$). We introduce a useful classification which contains 4 classes of models defined by the presence or absence of energy transfer and by the stationarity ($w = const.$ and $\\beta = const.$) or/and non stationarity ($w$ or $\\beta$ time dependent) of the equations of state. It is shown that, for given $w$ and $\\beta$, the energy transfer defines $\\gamma$ and, therefore, the total gravitating mass and dynamics of the model. We study important examples of two-fluid FLRW models within the new classification. The behaviour of the energy content, gravitating mass, pressure, and the energy transfer are given as functions of the scale factor. We point out three characteristic scales, $a_E$, $a_{\\cal P}$ and $a_{\\cal M}$, which separate periods of time in which quintessence energy, pressure and gravitating mass dominate. Each sequence of the scales defines one of 6 evolution types.

A. Gromov; Yu. Baryshev; P. Teerikorpi

2002-09-23T23:59:59.000Z

270

A scattering approach to Casimir forces and radiative heat transfer for nanostructured surfaces out of thermal equilibrium  

E-Print Network (OSTI)

We develop an exact method for computing Casimir forces and the power of radiative heat transfer between two arbitrary nanostructured surfaces out of thermal equilibrium. The method is based on a generalization of the scattering approach recently used in investigations on the Casimir effect. Analogously to the equilibrium case, we find that also out of thermal equilibrium the shape and composition of the surfaces enter only through their scattering matrices. The expressions derived provide exact results in terms of the scattering matrices of the intervening surfaces.

Giuseppe Bimonte

2009-09-11T23:59:59.000Z

271

Glass Furnace Model (GFM) development and technology transfer program final report.  

Science Conference Proceedings (OSTI)

A Glass Furnace Model (GFM) was developed under a cost-shared R&D program by the U.S. Department of Energy's Argonne National Laboratory in close collaboration with a consortium of five glass industry members: Techneglas, Inc., Owens-Corning, Libbey, Inc., Osram Sylvania, Inc., and Visteon, Inc. Purdue University and Mississippi State University's DIAL Laboratory were also collaborators in the consortium. The GFM glass furnace simulation model that was developed is a tool industry can use to help define and evaluate furnace design changes and operating strategies to: (1) reduce energy use per unit of production; (2) solve problems related to production and glass quality by defining optimal operating windows to reduce cullet generation due to rejects and maximize throughput; and (3) make changes in furnace design and/or operation to reduce critical emissions, such as NO{sub x} and particulates. A two-part program was pursued to develop and validate the furnace model. The focus of the Part I program was to develop a fully coupled furnace model which had the requisite basic capabilities for furnace simulation. The principal outcome from the Phase I program was a furnace simulation model, GFM 2.0, which was copyrighted. The basic capabilities of GFM 2.0 were: (1) built-in burner models that can be included in the combustion space simulation; (2) a participating media spectral radiation model that maintains local and global energy balances throughout the furnace volume; and (3) a multiphase (liquid, solid) melt model that calculates (does not impose) the batch-melting rate and the batch length. The key objectives of the Part II program, which overlapped the Part I program were: (1) to incorporate a full multiphase flow analytical capability with reduced glass chemistry models in the glass melt model and thus be able to compute and track key solid, gas, and liquid species through the melt and the combustion space above; and (2) to incorporate glass quality indices into the simulation to facilitate optimization studies with regard to productivity, energy use and emissions. Midway through the Part II program, however, at the urging of the industrial consortium members, the decision was made to refocus limited resources on transfer of the existing GFM 2.0 software to the industry to speed up commercialization of the technology. This decision, in turn, necessitated a de-emphasis of the development of the planned final version of the GFM software that had full multiphase capability, GFM 3.0. As a result, version 3.0 was not completed; considerable progress, however, was made before the effort was terminated. The objectives of the Technology Transfer program were to transfer the Glass Furnace Model (GFM) to the glass industry and to promote its widespread use by providing the requisite technical support to allow effective use of the software. GFM Version 2.0 was offered at no cost on a trial, six-month basis to expedite its introduction to and use by the industry. The trial licenses were issued to generate a much more thorough user beta test of the software than the relatively small amount completed by the consortium members prior to the release of version 2.0.

Lottes, S. A.; Petrick, M.; Energy Systems

2007-12-04T23:59:59.000Z

272

Report of a workshop on the impact of chemicals on the radiative transfer imbalance  

SciTech Connect

This workshop delineates the significant factors, possessed by any chemical, that may directly or indirectly affect the radiation balance of the atmosphere. Atmospheric physics research has already given information on direct and indirect effects. An example of direct effect is the cumulative infrared greenhouse effect of several trace gases, some of which are anthropogenic, and the short wave radiative effects of unactivated aerosol particles in clouds. Examples of indirect effects are those of aerosols as they change cloud droplet size distributions and hence albedo and radiative properties, and as found in observations of albedo and absorption anomalies in clouds, and cloud modification by urban pollution. 26 references.

DeLuisi, J.J. (ed.)

1979-01-01T23:59:59.000Z

273

The Radiative Effects of Aerosols on Photochemical Smog: Measurements and Modeling  

E-Print Network (OSTI)

. High concentrations of both ozone and aerosols are observed in the eastern United States during stagnant weather conditions associated with transport from the W or NW; they show similar spatial and temporal patterns. We discuss a causal mechanism that may contribute to this correlation - the radiative effects of aerosols on photolysis rates. We measured j(NO 2 ), the rate coefficient for nitrogen dioxide photolysis, and column aerosol optical depths at NASA/Goddard Space Flight Center in Greenbelt, MD (39.01 ffi N and 76.87 ffi W) during the smog seasons of 1995 and 1997. Direct measurements and radiative transfer model calculations show that particles can reduce surface j(NO 2 ) by 5 - 60%, depending on solar zenith angle and aerosol loading. Although particle scattering by dense aerosol loading on smoggy days decreases near-surface photolysis rates, it increases the integrated boundary layer photolysis rates by up to 20% and leads to accelerated photochemical smog formation in ...

Kondragunta Dickerson Stenchikov; S. Kondragunta; R. R. Dickerson; G. Stenchikov; W. F. Ryan; B. Holben; R. W. Stewart

2000-01-01T23:59:59.000Z

274

Studies on the Bulk Transfer Coefficients over a Vegetated Surface with a Multilayer Energy Budget Model  

Science Conference Proceedings (OSTI)

A multilayer energy budget model for vegetation canopy is developed to describe the fluxes of sensible and latent heat exchanged between the vegetated surface and the atmosphere. The model gives satisfactory results when the calculated radiative ...

Junsei Kondo; Tsutomu Watanabe

1992-12-01T23:59:59.000Z

275

Coupled Reactor Kinetics and Heat Transfer Model for Heat Pipe Cooled Reactors  

SciTech Connect

Heat pipes are often proposed as cooling system components for small fission reactors. SAFE-300 and STAR-C are two reactor concepts that use heat pipes as an integral part of the cooling system. Heat pipes have been used in reactors to cool components within radiation tests (Deverall, 1973); however, no reactor has been built or tested that uses heat pipes solely as the primary cooling system. Heat pipe cooled reactors will likely require the development of a test reactor to determine the main differences in operational behavior from forced cooled reactors. The purpose of this paper is to describe the results of a systems code capable of modeling the coupling between the reactor kinetics and heat pipe controlled heat transport. Heat transport in heat pipe reactors is complex and highly system dependent. Nevertheless, in general terms it relies on heat flowing from the fuel pins through the heat pipe, to the heat exchanger, and then ultimately into the power conversion system and heat sink. A system model is described that is capable of modeling coupled reactor kinetics phenomena, heat transfer dynamics within the fuel pins, and the transient behavior of heat pipes (including the melting of the working fluid). The paper focuses primarily on the coupling effects caused by reactor feedback and compares the observations with forced cooled reactors. A number of reactor startup transients have been modeled, and issues such as power peaking, and power-to-flow mismatches, and loading transients were examined, including the possibility of heat flow from the heat exchanger back into the reactor. This system model is envisioned as a tool to be used for screening various heat pipe cooled reactor concepts, for designing and developing test facility requirements, for use in safety evaluations, and for developing test criteria for in-pile and out-of-pile test facilities.

WRIGHT,STEVEN A.; HOUTS,MICHAEL

2000-11-22T23:59:59.000Z

276

On the application of the MODTRAN4 atmospheric radiative transfer code to optical remote sensing  

Science Conference Proceedings (OSTI)

The quantification of atmospheric effects on the solar radiation measured by a spaceborne or airborne optical sensor is required for some key tasks in remote sensing, such as atmospheric correction, simulation of realistic scenarios or retrieval of atmospheric ...

Luis Guanter; Rudolf Richter; Hermann Kaufmann

2009-01-01T23:59:59.000Z

277

Four-Stream Spherical Harmonic Expansion Approximation for Solar Radiative Transfer  

Science Conference Proceedings (OSTI)

This paper presents a four-stream extension of the ?-Eddington approximation by considering the higher-order spherical harmonic expansion in radiative intensity. By using the orthogonality relation of the spherical harmonic functions, the ...

J. Li; V. Ramaswamy

1996-04-01T23:59:59.000Z

278

Effect of Spatial Organization on Solar Radiative Transfer in Three-Dimensional Idealized Stratocumulus Cloud Fields  

Science Conference Proceedings (OSTI)

To relate the error associated with 1D radiative calculations to the geometrical scales of cloud organization and/or in-cloud optical inhomogeneities, a new idealized methodology, based on a Fourier statistical technique, has been developed. ...

F. Di Giuseppe; A. M. Tompkins

2003-08-01T23:59:59.000Z

279

Low Dose Radiation Research Program: Modeling Intercellular Interactions  

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

Modeling Intercellular Interactions During Radiation Carcinogenesis Modeling Intercellular Interactions During Radiation Carcinogenesis Authors: Rainer K Sachs,1 Michael Chan,2 Lynn Hlatky,3 Philip Hahnfeldt3 Institutions: 1Departments of Mathematics and Physics, University of California Berkeley California; 2School of Medicine, University of California at San Diego, La Jolla California; 3Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston Massachusetts Abstract By modulating the microenvironment of malignant or pre-malignant epithelial cells, inhibitory or stimulatory signals from nearby cells, including those in stromal and vascular tissues, can play a key role in carcinogenesis; cancer is ultimately a disease of a whole-cell community, not just of a single cell, clone, or cell lineage. However, current commonly used

280

Spatial transfer functions: a unified approach to specifying deformation in volume modeling and animation  

Science Conference Proceedings (OSTI)

In this paper, we introduce the concept of spatial transfer functions as a unified approach to volume modeling and animation. A spatial transfer function is a function that defines the geometrical transformation of a scalar field in space, and is a generalization ...

M. Chen; D. Silver; A. S. Winter; V. Singh; N. Cornea

2003-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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
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281

Modeling, fabrication and characterization of micro-coils as magnetic inductors for wireless power transfer  

Science Conference Proceedings (OSTI)

This work presents modeling, fabrication and characterization of planar microcoils for wireless power transfer in medical implanted devices, proposing integrated technology as a way to reduce the dimensions and achieve higher efficiency. The wireless ... Keywords: Inductive coupling, Inductive planar coils, Wireless power transfer

Massimiliano Amato, Francesco Dalena, Cristina Coviello, Massimo De Vittorio, Simona Petroni

2013-11-01T23:59:59.000Z

282

Modeling Surface Sensible Heat Flux Using Surface Radiative Temperatures in a Simple Urban Area  

Science Conference Proceedings (OSTI)

Sensible heat fluxes over a light industrial area in Vancouver, British Columbia, Canada, are analyzed from observed tower fluxes and modeled using a bulk heat transfer approach. The bulk transfer models are initialized using remotely sensed ...

J. A. Voogt; C. S. B. Grimmond

2000-10-01T23:59:59.000Z

283

Validation of General Circulation Model Radiative Fluxes Using Surface Observations  

Science Conference Proceedings (OSTI)

The surface radiative fluxes of the ECHAM3 General Circulation Model (GCM) with T2 1, T42, and T 106 resolutions have been validated using observations from the Global Energy Balance Archive (GEBA, World Climate Program-Water Project A7). GEBA ...

Martin Wild; Atsumu Ohmura; Hans Gilgen; Erich Roeckner

1995-05-01T23:59:59.000Z

284

An adaptive radiation model for the origin of new gene functions  

E-Print Network (OSTI)

Foster, P.L. Adaptive radiation of a frameshift mutation inThe Ecology of Adaptive Radiation, (Oxford University Press,18 th , 2004) An adaptive radiation model for the origin of

Francino, M. Pilar

2004-01-01T23:59:59.000Z

285

A transient heat and mass transfer model of residential attics used to simulate radiant barrier retrofits. Part 1: Development  

SciTech Connect

This paper describes a transient heat and mass transfer model of residential attics. The model is used to predict hourly ceiling heat gain/loss in residences with the purpose of estimating reductions in cooling and heating loads produced by radiant barriers. The model accounts for transient conduction, convection, and radiation and incorporates moisture and air transport across the attic. Environmental variables, such as solar loads on outer attic surfaces and sky temperatures, are also estimated. The model is driven by hourly weather data which include: outdoor dry bulb air temperature, horizontal solar and sky radiation, wind speed and direction, relative humidity (or dew point), and cloud cover data. The output of the model includes ceiling heat fluxes, inner and outer heat fluxes from all surfaces, inner and outer surface temperatures, and attic dry bulb air temperatures. The calculated fluxes have been compared to experimental data of side-by-side testing of attics retrofit with radiant barriers. The model predicts ceiling heat flows with an error of less than 10% for most cases.

Medina, M.A. [Texas A and M Univ., Kingsville, TX (United States). Dept. of Mechanical and Industrial Engineering; O`Neal, D.L. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering; Turner, W.D. [Texas Engineering Experiment Station, College Station, TX (United States). Energy Systems Lab.

1998-02-01T23:59:59.000Z

286

Heat transfer research and power cycle transient modeling  

DOE Green Energy (OSTI)

Fine axial flutes enhance heat transfer in vertical shell-and-tube exchangers with water inside the tubes and ammonia evaporating or condensing in layer flow on the shell side. Single-tube experiments with R-11 and ammonia indicate local shell-side coefficients 3 to 5 times those for corresponding smooth tubes. Single-tube experiments with water indicate that at moderate velocities the tube-side coefficients are enhanced by a factor equal to the ratio of fluted-to-smooth surface areas while the fluid friction is similarly increased. The experimental data are transformed into mean individual coefficients for ammonia and water. Overall coefficients for a particular case are presented to illustrate the efficacy of enhancement by flutes on one or both sides of the heat transfer surface. Means are described for using emerging data to predict the static and dynamic behavior of the power cycle and the interactions of components throughout the complete power plant.

Rothfus, R.R.; Neuman, C.P.

1977-03-23T23:59:59.000Z

287

Modelling excitonic-energy transfer in light-harvesting complexes  

E-Print Network (OSTI)

The theoretical and experimental study of energy transfer in photosynthesis has revealed an interesting transport regime, which lies at the borderline between classical transport dynamics and quantum-mechanical interference effects. Dissipation is caused by the coupling of electronic degrees of freedom to vibrational modes and leads to a directional energy transfer from the antenna complex to the target reaction-center. The dissipative driving is robust and does not rely on fine-tuning of specific vibrational modes. For the parameter regime encountered in the biological systems new theoretical tools are required to directly compare theoretical results with experimental spectroscopy data. The calculations require to utilize massively parallel graphics processor units (GPUs) for efficient and exact computations.

Kramer, Tobias

2013-01-01T23:59:59.000Z

288

Oxy-fuel combustion of coal and biomass, the effect on radiative and convective heat transfer and burnout  

Science Conference Proceedings (OSTI)

This paper focuses on results of co-firing coal and biomass under oxy-fuel combustion conditions on the RWEn 0.5 MWt Combustion Test Facility (CTF). Results are presented of radiative and convective heat transfer and burnout measurements. Two coals were fired: a South African coal and a Russian Coal under air and oxy-fuel firing conditions. The two coals were also co-fired with Shea Meal at a co-firing mass fraction of 20%. Shea Meal was also co-fired at a mass fraction of 40% and sawdust at 20% with the Russian Coal. An IFRF Aerodynamically Air Staged Burner (AASB) was used. The thermal input was maintained at 0.5 MWt for all conditions studied. The test matrix comprised of varying the Recycle Ratio (RR) between 65% and 75% and furnace exit O{sub 2} was maintained at 3%. Carbon-in-ash samples for burnout determination were also taken. Results show that the highest peak radiative heat flux and highest flame luminosity corresponded to the lowest recycle ratio. The effect of co-firing of biomass resulted in lower radiative heat fluxes for corresponding recycle ratios. Furthermore, the highest levels of radiative heat flux corresponded to the lowest convective heat flux. Results are compared to air firing and the air equivalent radiative and convective heat fluxes are fuel type dependent. Reasons for these differences are discussed in the main text. Burnout improves with biomass co-firing under both air and oxy-fuel firing conditions and burnout is also seen to improve under oxy-fuel firing conditions compared to air. (author)

Smart, John P.; Patel, Rajeshriben; Riley, Gerry S. [RWEnpower, Windmill Hill Business Park, Whitehill Way, Swindon, Wiltshire SN5 6PB, England (United Kingdom)

2010-12-15T23:59:59.000Z

289

Anatomical database generation for radiation transport modeling from computed tomography (CT) scan data  

SciTech Connect

Geometric models of the anatomy are used routinely in calculations of the radiation dose in organs and tissues of the body. Development of such models has been hampered by lack of detailed anatomical information on children, and models themselves have been limited to quadratic conic sections. This summary reviews the development of an image processing workstation used to extract anatomical information from routine diagnostic CT procedure. A standard IBM PC/AT microcomputer has been augmented with an automatically loading 9-track magnetic tape drive, an 8-bit 1024 {times} 1024 pixel graphics adapter/monitor/film recording package, a mouse/trackball assembly, dual 20 MB removable cartridge media, a 72 MB disk drive, and a printer. Software utilized by the workstation includes a Geographic Information System (modified for manipulation of CT images), CAD software, imaging software, and various modules to ease data transfer among the software packages. 5 refs., 3 figs.

Margle, S.M.; Tinnel, E.P.; Till, L.E.; Eckerman, K.F.; Durfee, R.C.

1989-01-01T23:59:59.000Z

290

Automotive Underhood Thermal Management Analysis Using 3-D Coupled Thermal-Hydrodynamic Computer Models: Thermal Radiation Modeling  

SciTech Connect

The goal of the radiation modeling effort was to develop and implement a radiation algorithm that is fast and accurate for the underhood environment. As part of this CRADA, a net-radiation model was chosen to simulate radiative heat transfer in an underhood of a car. The assumptions (diffuse-gray and uniform radiative properties in each element) reduce the problem tremendously and all the view factors for radiation thermal calculations can be calculated once and for all at the beginning of the simulation. The cost for online integration of heat exchanges due to radiation is found to be less than 15% of the baseline CHAD code and thus very manageable. The off-line view factor calculation is constructed to be very modular and has been completely integrated to read CHAD grid files and the output from this code can be read into the latest version of CHAD. Further integration has to be performed to accomplish the same with STAR-CD. The main outcome of this effort is to obtain a highly scalable and portable simulation capability to model view factors for underhood environment (for e.g. a view factor calculation which took 14 hours on a single processor only took 14 minutes on 64 processors). The code has also been validated using a simple test case where analytical solutions are available. This simulation capability gives underhood designers in the automotive companies the ability to account for thermal radiation - which usually is critical in the underhood environment and also turns out to be one of the most computationally expensive components of underhood simulations. This report starts off with the original work plan as elucidated in the proposal in section B. This is followed by Technical work plan to accomplish the goals of the project in section C. In section D, background to the current work is provided with references to the previous efforts this project leverages on. The results are discussed in section 1E. This report ends with conclusions and future scope of work in section F.

Pannala, S.; D'Azevedo, E.; Zacharia, T.

2002-02-26T23:59:59.000Z

291

3D Lya radiation transfer. II. Fitting the Lyman break galaxy MS 1512-cB58 and implications for Lya emission in high-z starbursts  

E-Print Network (OSTI)

Using our 3D Lya radiation transfer code, we compute the radiation transfer of Lya and UV continuum photons including dust. Observational constraints on the neutral gas (column density, kinematics, etc.) are taken from other analysis of this object. RESULTS: The observed Lya profile of MS 1512--cB58 is reproduced for the first time taking radiation transfer and all observational constraints into account. The observed absorption profile is found to result naturally from the observed amount of dust and the relatively high HI column density. Radiation transfer effects and suppresion by dust transform a strong intrinsic Lya emission with EW(Lya)>~ 60 Ang into the observed faint superposed Lya emission peak. We propose that the vast majority of LBGs have intrinsically EW(Lya)~60-80 Ang or larger, and that the main physical parameter responsible for the observed variety of Lya strengths and profiles in LBGs is N_H and the accompanying variation of the dust content. Observed EW(Lya) distributions, Lya luminosity functions, and related quantities must therefore be corrected for radiation transfer and dust effects. The implications from our scenario on the duty-cycle of Lya emitters are also discussed.

Daniel Schaerer; Anne Verhamme

2008-01-08T23:59:59.000Z

292

Evaluation and Transferability of the Noah Land Surface Model in Semiarid Environments  

Science Conference Proceedings (OSTI)

This paper investigates the performance of the National Centers for Environmental Prediction (NCEP) Noah land surface model at two semiarid sites in southern Arizona. The goal is to evaluate the transferability of calibrated parameters (i.e., ...

Terri S. Hogue; Luis Bastidas; Hoshin Gupta; Soroosh Sorooshian; Ken Mitchell; William Emmerich

2005-02-01T23:59:59.000Z

293

Transferability of a Three-Dimensional Air Quality Model between Two Different Sites in Complex Terrain  

Science Conference Proceedings (OSTI)

The three-dimensional, diagnostic, particle-in-cell transport and diffusion model MATHEW/ADPIC is used to test its transferability from one site in complex terrain to another with different characteristics, under stable nighttime drainage flow ...

Rolf Lange

1989-07-01T23:59:59.000Z

294

Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)  

Science Conference Proceedings (OSTI)

This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

Tabares Velasco, P. C.

2011-04-01T23:59:59.000Z

295

A Comparison Between Modeled and Measured Clear-Sky Radiative Shortwave Fluxes in Arctic Environments, with Special Emphasis on Diffuse Radiation  

SciTech Connect

The ability of the SBDART radiative transfer model to predict clear-sky diffuse and direct normal broadband shortwave irradiances is investigated. Model calculations of these quantities are compared with data from the Atmospheric Radiation Measurement (ARM) programs Southern Great Plains (SGP) and North Slope of Alaska (NSA) sites. The model tends to consistently underestimate the direct normal irradiances at both sites by about 1%. In regards to clear-sky diffuse irradiance, the model overestimates this quantity at the SGP site in a manner similar to what has been observed in other studies (Halthore and Schwartz, 2000). The difference between the diffuse SBDART calculations and Halthore and Schwartzs MODTRAN calculations is very small, thus demonstrating that SBDART performs similarly to MODTRAN. SBDART is then applied to the NSA site, and here it is found that the discrepancy between the model calculations and corrected diffuse measurements (corrected for daytime offsets, Dutton et al., 2001) is 0.4 W/m2 when averaged over the 12 cases considered here. Two cases of diffuse measurements from a shaded black and white pyranometer are also compared with the calculations and the discrepancy is again minimal. Thus, it appears as if the diffuse discrepancy that exists at the SGP site does not exist at the NSA sites. We cannot yet explain why the model predicts diffuse radiation well at one site but not at the other.

Barnard, James C.; Flynn, Donna M.

2002-10-08T23:59:59.000Z

296

Transient PVT measurements and model predictions for vessel heat transfer. Part II.  

SciTech Connect

Part I of this report focused on the acquisition and presentation of transient PVT data sets that can be used to validate gas transfer models. Here in Part II we focus primarily on describing models and validating these models using the data sets. Our models are intended to describe the high speed transport of compressible gases in arbitrary arrangements of vessels, tubing, valving and flow branches. Our models fall into three categories: (1) network flow models in which flow paths are modeled as one-dimensional flow and vessels are modeled as single control volumes, (2) CFD (Computational Fluid Dynamics) models in which flow in and between vessels is modeled in three dimensions and (3) coupled network/CFD models in which vessels are modeled using CFD and flows between vessels are modeled using a network flow code. In our work we utilized NETFLOW as our network flow code and FUEGO for our CFD code. Since network flow models lack three-dimensional resolution, correlations for heat transfer and tube frictional pressure drop are required to resolve important physics not being captured by the model. Here we describe how vessel heat transfer correlations were improved using the data and present direct model-data comparisons for all tests documented in Part I. Our results show that our network flow models have been substantially improved. The CFD modeling presented here describes the complex nature of vessel heat transfer and for the first time demonstrates that flow and heat transfer in vessels can be modeled directly without the need for correlations.

Felver, Todd G.; Paradiso, Nicholas Joseph; Winters, William S., Jr.; Evans, Gregory Herbert; Rice, Steven F.

2010-07-01T23:59:59.000Z

297

Modeling and Simulation of the ITER First Wall/Blanket Primary Heat Transfer System  

SciTech Connect

ITER inductive power operation is modeled and simulated using a thermal-hydraulics system code (RELAP5) integrated with a 3-D CFD (SC-Tetra) code. The Primary Heat Transfer System (PHTS) functions are predicted together with the main parameters operational ranges. The control algorithm strategy and derivation are summarized as well. The First Wall and Blanket modules are the primary components of PHTS, used to remove the major part of the thermal heat from the plasma. The modules represent a set of flow channels in solid metal structure that serve to absorb the radiation heat and nuclear heating from the fusion reactions and to provide shield for the vacuum vessel. The blanket modules are water cooled. The cooling is forced convective with constant blanket inlet temperature and mass flow rate. Three independent water loops supply coolant to the three blanket sectors. The main equipment of each loop consists of a pump, a steam pressurizer and a heat exchanger. A major feature of ITER is the pulsed operation. The plasma does not burn continuously, but on intervals with large periods of no power between them. This specific feature causes design challenges to accommodate the thermal expansion of the coolant during the pulse period and requires active temperature control to maintain a constant blanket inlet temperature.

Ying, Alice [University of California, Los Angeles; Popov, Emilian L [ORNL

2011-01-01T23:59:59.000Z

298

ARM - Publications: Science Team Meeting Documents: ARM Radiative...  

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

ARM Radiative Transfer Modeling and Remote Sensing Clough, Shepard Atmospheric and Environmental Research Shephard, Mark Atmospheric and Environmental Research, Inc. Mlawer, Eli...

299

Author's personal copy Radiation transfer in photobiological carbon dioxide fixation and fuel  

E-Print Network (OSTI)

Engineering Department, Cockrell School of Engineering, The University of Texas at Austin, 204 E. Dean Keeton Street, Austin, TX 78705, USA a r t i c l e i n f o Article history: Received 26 April 2011 Received a c t Solar radiation is the energy source driving the metabolic activity of microorganisms able

Pilon, Laurent

300

THE I3RC: Bringing Together the Most Advanced Radiative Transfer Tools for Cloudy Atmospheres  

Science Conference Proceedings (OSTI)

The interaction of clouds with solar and terrestrial radiation is one of the most important topics of climate research. In recent years it has been recognized that only a full three-dimensional (3D) treatment of this interaction can provide ...

Robert F. Cahalan; Lazaros Oreopoulos; Alexander Marshak; K. Franklin Evans; Anthony B. Davis; Robert Pincus; Ken H. Yetzer; Bernhard Mayer; Roger Davies; Thomas P. Ackerman; Howard W. Barker; Eugene E. Clothiaux; Robert G. Ellingson; Michael J. Garay; Evgueni Kassianov; Stefan Kinne; Andreas Macke; William O'Hirok; Philip T. Partain; Sergei M. Prigarin; Alexei N. Rublev; Graeme L. Stephens; Frederic Szczap; Ezra E. Takara; Tmas Vrnai; Guoyong Wen; Tatiana B. Zhuravleva

2005-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

An Assessment of Radiation Damage Models and Methods  

SciTech Connect

The current state of development of the primary models used for investigating and simulating irradiation effects in structural alloys of interest to the U.S. DOE's Generation-IV reactor program are discussed. The underlying theory that supports model development is also described where appropriate. First, the key processes that underlie radiation-induced changes in material properties are summarized, and the types of radiation effects that subsequently arise are described. Future development work needed in order for theory, modeling, and computational materials science to support and add value to the Gen IV reactor materials program are then outlined. The expected specific outcomes and overall benefits of the required effort are: the knowledge to extrapolate material behavior to conditions for which there are no experimental data; systematic understanding of mechanisms and processes to enable confident interpolation between point-by-point experimental observations; acceleration of the development, selection, and qualification of materials for reactor service; and prediction of material response to real-world operating load histories which often involve a complicated superposition of time, temperature, radiation dose rate, and mechanical loading conditions. Opportunities for international collaboration to accelerate progress in all of the required research areas are briefly discussed, particularly in the context of two well coordinated, broad-based research projects on modeling and simulation of radiation effects on materials that are currently funded in Europe. In addition to providing the opportunity for substantial leveraging of the DOE-funded activities in this area, these projects may serve as models for future development within the Gen-IV program. The larger of these two projects, which involves 12 European research laboratories and 16 universities, is called PERFECT and is funded by the European Union. A smaller effort focusing on developing predictive models for fusion reactor materials is funded within the United Kingdom. Increased formal collaboration with these projects by DOE-funded materials scientists would be of substantial benefit to the Gen-IV program.

Stoller, Roger E [ORNL; Mansur, Louis K [ORNL

2005-05-01T23:59:59.000Z

302

Problem-orientable numerical algorithm for modelling multi-dimensional radiative MHD flows in astrophysics -- the hierarchical solution scenario  

E-Print Network (OSTI)

We present a hierarchical approach for enhancing the robustness of numerical solvers for modelling radiative MHD flows in multi-dimensions. This approach is based on clustering the entries of the global Jacobian in a hierarchical manner that enables employing a variety of solution procedures ranging from a purely explicit time-stepping up to fully implicit schemes. A gradual coupling of the radiative MHD equation with the radiative transfer equation in higher dimensions is possible. Using this approach, it is possible to follow the evolution of strongly time-dependent flows with low/high accuracies and with efficiency comparable to explicit methods, as well as searching quasi-stationary solutions for highly viscous flows. In particular, it is shown that the hierarchical approach is capable of modelling the formation of jets in active galactic nuclei and reproduce the corresponding spectral energy distribution with a reasonable accuracy.

A. A. Hujeirat

2004-10-26T23:59:59.000Z

303

Low Dose Radiation Research Program: Computational Modeling of Biochemical  

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

Computational Modeling of Biochemical Pathways Linking Ionizing Computational Modeling of Biochemical Pathways Linking Ionizing Radiation to Cell Cycle Arrest, Apoptosis, and Tumor Incidence Authors: Yuchao Maggie Zhao and Rory Conolly Institutions: Center for Computational Systems Biology CIIT Centers for Health Research Long-Range Goal: To develop an integrated, computational framework for the prediction of low-dose-response to ionizing radiation (IR) in people. Methodology: To provide a flexible framework to evaluate mechanisms of cellular adaptive responses after exposure to IR, three progressively more complicated descriptions of biochemical pathways linking DNA damage with cell-cycle checkpoint control and apoptosis were developed. These descriptions focus on p53-dependent checkpoint arrest and apoptosis, p73-dependent apoptosis, and Chk2-dependent checkpoint arrest,

304

Modeling of Heat and Mass Transfer in Fusion Welding  

Science Conference Proceedings (OSTI)

In fusion welding, parts are joined together by melting and subsequent solidification. Although this principle is simple, complex transport phenomena take place during fusion welding, and they determine the final weld quality and performance. The heat and mass transfer in the weld pool directly affect the size and shape of the pool, the solidification microstructure, the formation of weld defects such as porosity and humping, and the temperature distribution in the fusion zone and heat-affected zone (HAZ). Furthermore, the temperature evolution affects the kinetics and extent of various solid-state phase transformations, which in turn determine the final weld microstructure and mechanical properties. The formation of residual stresses and distortion originates from the thermal expansion and contraction during welding heating and cooling, respectively.

Zhang, Wei [ORNL

2011-01-01T23:59:59.000Z

305

The Estimation of Hourly Global Solar Radiation Using a Cloud Cover Model Developed at Blytheville, Arkansas  

Science Conference Proceedings (OSTI)

The lack of a comprehensive solar radiation monitoring network throughout the United States has led to extensive modeling. Some of the models use a measured component, usually the global solar radiation, to predict the other components, direct ...

W. D. Turner; Abdulaziz Mujahid

1984-05-01T23:59:59.000Z

306

Origins of the solar radiation biases over the Southern Ocean in CFMIP2 models  

Science Conference Proceedings (OSTI)

Current climate models generally reflect too little solar radiation over the Southern Ocean, which may be the leading cause of the prevalent sea-surface temperature biases in climate models. We study the role of clouds the radiation biases in ...

A. Bodas-Salcedo; K. D. Williams; M. A. Ringer; I. Beau; J. N. S. Cole; J.-L. Dufresne; T. Koshiro; B. Stevens; Z. Wang; T. Yokohata

307

Radiative transfer in plane-parallel media and Cauchy integral equations II. The H-function  

E-Print Network (OSTI)

In the central part of this paper, we revisit the classical study of the H-function defined as the unique solution, regular in the right complex half-plane, of a Cauchy integral equation. We take advantage of our work on the N-function published in the first article of this series. The H-function is then used to solve a class of Cauchy integral equations occurring in transfer problems posed in plane-parallel media. We obtain a concise expression of the unique solution analytic in the right complex half-plane, then modified with the help of the residue theorem for numerical calculations.

B. Rutily; J. Bergeat; L. Chevallier

2006-01-16T23:59:59.000Z

308

A study of longwave radiation codes for climate studies: Validation with ARM observations and tests in general circulation models. Technical report, 16 March 1991--15 March 1992  

SciTech Connect

Research by the US Department of Energy (DOE) has shown that cloud radiative feedback is the single most important effect determining the magnitude of possible climatic responses to human activity. However, these effects are still not known at the levels needed for climate prediction. Consequently, DOE has launched a major initiative-- the Atmospheric Radiation Measurements (ARM) Program -- directed at improving the parameterization of the physics governing cloud and radiative processes in general circulation models (GCM`s). One specific goal of ARM is to improve the treatment of radiative transfer in GCM`s under clear-sky, general overcast and broken cloud conditions. Our approach to developing the radiation model will be to test existing models in an iterative, predictive fashion. We will supply the Clouds and Radiative Testbed (CART) with a set of models to be compared with operationally observed data. The differences we find will lead to the development of new models to be tested with new data. Similarly, our GCM studies will use existing GCM`s to study the radiation sensitivity problem. We anticipate that the outcome of this approach will provide both a better longwave radiative forcing algorithm and a better understanding of how longwave radiative forcing influences the equilibrium climate of the atmosphere.

Ellingson, R.G.; Baer, F.

1992-06-01T23:59:59.000Z

309

Modeling and Analysis of Solar Radiation Potentials on Building Rooftops  

Science Conference Proceedings (OSTI)

The active application of photovoltaic for electricity generation could effectively transform neighborhoods and commercial districts into small, localized power plants. This application, however, relies heavily on an accurate estimation of the amount of solar radiation that is available on individual building rooftops. While many solar energy maps exist at higher spatial resolution for concentrated solar energy applications, the data from these maps are not suitable for roof-mounted photovoltaic for several reasons, including lack of data at the appropriate spatial resolution and lack of integration of building-specific characteristics into the models used to generate the maps. To address this problem, we have developed a modeling framework for estimating solar radiation potentials on individual building rooftops that is suitable for utility-scale applications as well as building-specific applications. The framework uses light detection and ranging (LIDAR) data at approximately 1-meter horizontal resolution and 0.3-meter vertical resolution as input for modeling a large number of buildings quickly. One of the strengths of this framework is the ability to parallelize its implementation. Furthermore, the framework accounts for building specific characteristics, such as roof slope, roof aspect, and shadowing effects, that are critical to roof-mounted photovoltaic systems. The resulting data has helped us to identify the so-called solar panel sweet spots on individual building rooftops and obtain accurate statistics of the variation in solar radiation as a function of time of year and geographical location.

Omitaomu, Olufemi A [ORNL; Kodysh, Jeffrey B [ORNL; Bhaduri, Budhendra L [ORNL

2012-01-01T23:59:59.000Z

310

Spreader-Bar Radiation Detection System Enhancements: A Modeling and Simulation Study  

SciTech Connect

This report provides the modeling and simulation results of the investigation of enhanced spreader bar radiation detection systems.

Ely, James H.; Ashbaker, Eric D.; Batdorf, Michael T.; Baciak, James E.; Hensley, Walter K.; Jarman, Kenneth D.; Robinson, Sean M.; Sandness, Gerald A.; Schweppe, John E.

2012-11-13T23:59:59.000Z

311

The Simplest Models of Radiative Neutrino Mass: Excluding Simplified Zee Models and Beyond  

E-Print Network (OSTI)

The complexity of radiative neutrino-mass models can be judged by: (i) whether they require the imposition of ad hoc symmetries, (ii) the number of new multiplets they introduce, and (iii) the number of arbitrary parameters that appear. Adopting the view that the imposition of arbitrary new symmetries is the least appealing approach, the simplest models have two new multiplets and a minimal number of new parameters. With this in mind, we search for the simplest models of radiative neutrino mass. We are lead to two new models, containing a real scalar triplet and a charged scalar doublet (respectively), in addition to the charged singlet scalar considered by Zee [h^+\\sim(1,1,2)]. The new models are essentially simplified versions of the Zee model and appear to be \\emph{the simplest} models of radiative neutrino mass. However, these models are only of pedagogical interest; despite successfully generating nonzero masses, present-day data is sufficient to rule them out. The lessons learned from these models also enable one to exclude a more general class of radiative models. Moving beyond the minimal cases, we find a new model of two-loop masses that employs the charged doublet \\Phi\\sim(1,2,3) and the doubly-charged scalar k^{++}\\sim(1,1,4).

Sandy S. C. Law; Kristian L. McDonald

2013-03-26T23:59:59.000Z

312

Energy transfers in shell models for MHD turbulence  

E-Print Network (OSTI)

A systematic procedure to derive shell models for MHD turbulence is proposed. It takes into account the conservation of ideal quadratic invariants such as the total energy, the cross-helicity and the magnetic helicity as well as the conservation of the magnetic energy by the advection term in the induction equation. This approach also leads to simple expressions for the energy exchanges as well as to unambiguous definitions for the energy fluxes. When applied to the existing shell models with nonlinear interactions limited to the nearest neighbour shells, this procedure reproduces well known models but suggests a reinterpretation of the energy fluxes.

T. Lessinnes; M. K. Verma; D. Carati

2008-07-31T23:59:59.000Z

313

Vibrational energy transfer in a diesel engine  

Science Conference Proceedings (OSTI)

The paths of vibrational energy transfer in a diesel engine were investigated in order to obtain insight into ways of reducing this transfer to the exterior surfaces and thereby reduce the radiated noise. The engine was tested in a nonrunning condition with simulated internal forces in order to study the different transfer paths separately. Vibration response measurements were made of individual engine components and lumped?parameter models were developed to simulate this response. These models were then used to determine component design changes that would reduce the energy transfer. Two design changes were implemented in the engine and a reduction of the energy transfer was achieved as predicted.

R. G. DeJong; R. H. Lyon

1977-01-01T23:59:59.000Z

314

Radiative Energy Budget Estimates for the 1979 Southwest Summer Monsoon  

Science Conference Proceedings (OSTI)

Obsemations of temperature moisture, cloud amount, cloud height and soil-derived aerosols are incorporated into radiative transfer models to yield estimates of the tropospheric and surface radiative energy budgets for the summer Monsoon of 1979. ...

Steven A. Ackerman; Stephen K. Cox

1987-10-01T23:59:59.000Z

315

Uncertainties in the Radiative Forcing Due to Sulfate Aerosols  

Science Conference Proceedings (OSTI)

Radiative transfer calculations based on a new sulfate distribution from a chemistry-transport model simulation have been performed. A wide range of sensitivity experiments have been performed to illustrate the large uncertainty in the radiative ...

Gunnar Myhre; Frode Stordal; Tore F. Berglen; Jostein K. Sundet; Ivar S. A. Isaksen

2004-03-01T23:59:59.000Z

316

Photosynthetic models with maximum entropy production in irreversible charge transfer steps  

Science Conference Proceedings (OSTI)

Steady-state bacterial photosynthesis is modelled as cyclic chemical reaction and is examined with respect to overall efficiency, power transfer efficiency, and entropy production. A nonlinear flux-force relationship is assumed. The simplest two-state ... Keywords: Bacterial photosynthesis, Efficiency, Entropy production, Kinetic models, Power

Davor Jureti?; PaKo Upanovi?

2003-12-01T23:59:59.000Z

317

Low Dose Radiation Research Program: Use of Computational Modeling to  

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

Use of Computational Modeling to Evaluate Hypotheses about the Use of Computational Modeling to Evaluate Hypotheses about the Molecular and Cellular Mechanisms of Bystander Effects Authors: Yuchao “Maggie” Zhao and Rory Conolly Institutions: CIIT Centers for Health Research, 6 Davis Drive, Research Triangle Park, North Carolina A detailed understanding of the biological mechanisms of radiation-induced damage at the molecular and cellular levels is needed for accurate assessment of the shape of the dose-response curve for radiationinduced health effects in the intact organism. Computational models can contribute to the improved understanding of mechanisms through integration of data and quantitative evaluation of hypotheses. We propose to develop a novel computational model of bystander effects elicited by oxidative stress and a

318

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

319

Development of a Transient Heat and Mass Transfer Model of Residential Attics to Predict Energy Savings Produced by the Use of Radiant Barriers  

E-Print Network (OSTI)

A transient heat and mass transfer model was developed to predict ceiling heat gain/loss through the attic space in residences and to accurately estimate savings in cooling and heating loads produced by the use of radiant barriers. The model accounted for transient conduction, convection and radiation and incorporated moisture and air transport across the attic. Environmental variables such as solar loads on outer attic surfaces and sky temperatures were also estimated. The model was driven by hourly weather data which included: time, outdoor air temperature, horizontal sun and sky radiation, wind speed and direction, relative humidity (dew point), and cloud cover data. The outputs of the model were ceiling heat fluxes, inner and outer heat fluxes from all surfaces, inner and outer surface temperatures and attic air temperatures. Transient conduction was modeled using response factors. Response factors were calculated for each attic component based on construction type. Convective heat transfer was modeled using flat plate correlations found in the literature and radiative heat transfer was modeled using radiation enclosure theory. Moisture was incorporated via a condensation/evaporation model. A new procedure was developed to account for attic air stratification. Both forced and natural attic ventilation patterns were added to the model for three types of louver combination arrangements. An iterative technique was used to solve a set of simultaneous heat balance equations. The model predictions were compared to experimental data gathered throughout a three year experimental effort of side-by-side testing of attics retrofit with radiant barriers. The model was compared to the experimental data for a variety of situations which included: different attic insulation levels, various attic airflow rates, cooling and heating seasons, and different radiant barrier orientations. The model predicted ceiling heat flows within 10% for most cases. The model was used to run simulations and parametric studies under a diversity of climates, insulation levels and attic airflow patterns. Model predictions and results were presented on the basis of savings produced by the use of radiant barriers. Hourly, daily, and seasonal predictions by the model were in excellent agreement with observed experimental data and with literature.

Medina, M. A.

1992-12-01T23:59:59.000Z

320

Spectroscopic investigation of photo-induced proton-coupled electron transfer and Dexter energy transfer in model systems  

E-Print Network (OSTI)

Spectroscopic investigations of systems designed to advance the mechanistic interrogation of photo-induced proton coupled electron transfer (PCET) and proton-coupled (through-bond) energy transfer (PCEnT) are presented. ...

Young, Elizabeth R. (Elizabeth Renee), 1980-

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

High Resolution Aerosol Modeling: Decadal Changes in Radiative Forcing  

Science Conference Proceedings (OSTI)

The Atmospheric Science Division of LLNL has performed high-resolution calculations of direct sulfate forcing using a DOE-provided computer resource at NERSC. We integrated our global chemistry-aerosol model (IMPACT) with the LLNL high-resolution global climate model (horizontal resolution as high as 100 km) to examine the temporal evolution of sulfate forcing since 1950. We note that all previous assessments of sulfate forcing reported in IPCC (2001) were based on global models with coarse spatial resolutions ({approx} 300 km or even coarser). However, the short lifetime of aerosols ({approx} days) results in large spatial and temporal variations of radiative forcing by sulfate. As a result, global climate models with coarse resolutions do not accurately simulate sulfate forcing on regional scales. It requires much finer spatial resolutions in order to address the effects of regional anthropogenic SO{sub 2} emissions on the global atmosphere as well as the effects of long-range transport of sulfate aerosols on the regional climate forcing. By taking advantage of the tera-scale computer resources at NERSC, we simulated the historic direct sulfate forcing at much finer spatial resolutions than ever attempted before. Furthermore, we performed high-resolution chemistry simulations and saved monthly averaged oxidant fields, which will be used in subsequent simulations of sulfate aerosol formation and their radiative impact.

Bergmann, D J; Chuang, C C; Govindasamy, B; Cameron-Smith, P J; Rotman, D A

2005-02-01T23:59:59.000Z

322

Complex Geometry Creation and Turbulent Conjugate Heat Transfer Modeling  

Science Conference Proceedings (OSTI)

The multiphysics capabilities of COMSOL provide the necessary tools to simulate the turbulent thermal-fluid aspects of the High Flux Isotope Reactor (HFIR). Version 4.1, and later, of COMSOL provides three different turbulence models: the standard k-{var_epsilon} closure model, the low Reynolds number (LRN) k-{var_epsilon} model, and the Spalart-Allmaras model. The LRN meets the needs of the nominal HFIR thermal-hydraulic requirements for 2D and 3D simulations. COMSOL also has the capability to create complex geometries. The circular involute fuel plates used in the HFIR require the use of algebraic equations to generate an accurate geometrical representation in the simulation environment. The best-estimate simulation results show that the maximum fuel plate clad surface temperatures are lower than those predicted by the legacy thermal safety code used at HFIR by approximately 17 K. The best-estimate temperature distribution determined by COMSOL was then used to determine the necessary increase in the magnitude of the power density profile (PDP) to produce a similar clad surface temperature as compared to the legacy thermal safety code. It was determined and verified that a 19% power increase was sufficient to bring the two temperature profiles to relatively good agreement.

Bodey, Isaac T [ORNL; Arimilli, Rao V [ORNL; Freels, James D [ORNL

2011-01-01T23:59:59.000Z

323

Calculating Monthly Radiative Fluxes and Heating Rates fromMonthly Cloud Observations  

Science Conference Proceedings (OSTI)

The radiative transfer model from NCARs general circulation model CCM3 is modified to calculate monthly radiative fluxes and heating rates from monthly observations of cloud properties from the International Satellite Cloud Climatology Project ...

John W. Bergman; Harry H. Hendon

1998-12-01T23:59:59.000Z

324

Models for Metal Hydride Particle Shape, Packing, and Heat Transfer  

E-Print Network (OSTI)

A multiphysics modeling approach for heat conduction in metal hydride powders is presented, including particle shape distribution, size distribution, granular packing structure, and effective thermal conductivity. A statistical geometric model is presented that replicates features of particle size and shape distributions observed experimentally that result from cyclic hydride decreptitation. The quasi-static dense packing of a sample set of these particles is simulated via energy-based structural optimization methods. These particles jam (i.e., solidify) at a density (solid volume fraction) of 0.665+/-0.015 - higher than prior experimental estimates. Effective thermal conductivity of the jammed system is simulated and found to follow the behavior predicted by granular effective medium theory. Finally, a theory is presented that links the properties of bi-porous cohesive powders to the present systems based on recent experimental observations of jammed packings of fine powder. This theory produces quantitative experimental agreement with metal hydride powders of various compositions.

Kyle C. Smith; Timothy S. Fisher

2012-05-04T23:59:59.000Z

325

A mass transfer model of ammonia volatilisation from anaerobic digestate  

SciTech Connect

Anaerobic digestion (AD) is becoming increasingly popular for treating organic waste. The methane produced can be burned to generate electricity and the digestate, which is high in mineral nitrogen, can be used as a fertiliser. In this paper we evaluate potential losses of ammonia via volatilisation from food waste anaerobic digestate using a closed chamber system equipped with a sulphuric acid trap. Ammonia losses represent a pollution source and, over long periods could reduce the agronomic value of the digestate. Observed ammonia losses from the experimental system were linear with time. A simple non-steady-state partitioning model was developed to represent the process. After calibration, the model was able to describe the behaviour of ammonia in the digestate and in the trap very well. The average rate of volatilisation was approximately 5.2 g N m{sup -2} week{sup -1}. The model was used to extrapolate the findings of the laboratory study to a number of AD storage scenarios. The simulations highlight that open storage of digestate could result in significant losses of ammonia to the atmosphere. Losses are predicted to be relatively minor from covered facilities, particularly if depth to surface area ratio is high.

Whelan, M.J., E-mail: m.j.whelan@cranfield.ac.u [School of Applied Sciences, Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL (United Kingdom); Everitt, T.; Villa, R. [School of Applied Sciences, Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL (United Kingdom)

2010-10-15T23:59:59.000Z

326

A simplified model of the thermal interaction of a Venetian blind located on the indoor glazing surface of a window.  

E-Print Network (OSTI)

??A simplified model was developed to predict the radiative and convective heat transfer in complex fenestration systems, including the effect of solar radiation. The focus (more)

Roeleveld, Derek

2007-01-01T23:59:59.000Z

327

A critical review of the ASHRAE solar radiation model  

Science Conference Proceedings (OSTI)

Inconsistencies are shown to exist in the presentation and formulation of the ASHRAE solar radiation model. To remove them, it is proposed: 1. To include in the Fundamentals Handbook the clearness number in the expressions for the direct and, in particular, the sky diffuse irradiation under cloudless conditions, and 2. To rewrite the expressions for cloud sky conditions so that they reduce to the cloudless formulation when the cloud cover is zero and they do not give rise to negative values of the sky diffuse irradiation as is presently the case under certain conditions.

Galanis, N.; Chatigny, R.

1986-01-01T23:59:59.000Z

328

Radiation thermo-chemical models of protoplanetary disks I. Hydrostatic disk structure and inner rim  

E-Print Network (OSTI)

This paper introduces a new disk code, called ProDiMo, to calculate the thermo-chemical structure of protoplanetary disks and to interpret gas emission lines from UV to sub-mm. We combine frequency-dependent 2D dust continuum radiative transfer, kinetic gas-phase and UV photo-chemistry, ice formation, and detailed non-LTE heating & cooling balance with the consistent calculation of the hydrostatic disk structure. We include FeII and CO ro-vibrational line heating/cooling relevant for the high-density gas close to the star, and apply a modified escape probability treatment. The models are characterized by a high degree of consistency between the various physical, chemical and radiative processes, where the mutual feedbacks are solved iteratively. In application to a T Tauri disk extending from 0.5AU to 500AU, the models are featured by a puffed-up inner rim and show that the dense, shielded and cold midplane (z/r<0.1, Tg~Td) is surrounded by a layer of hot (5000K) and thin (10^7 to 10^8 cm^-3) atomic ga...

Woitke, Peter; Thi, Wing-Fai

2009-01-01T23:59:59.000Z

329

Artificial Intelligence technique for modelling and forecasting of solar radiation data: a review  

Science Conference Proceedings (OSTI)

Artificial Intelligence (AI) has been used and applied in different sectors, such as engineering, economic, medicine, military, marine, etc. AI has also been applied for modelling, identification, optimisation, prediction, forecasting, and control ... Keywords: AI, FPGA, GAs, VHDL, artificial intelligence, fuzzy logic, genetic algorithms, hybrid systems, neural networks, photovoltaic systems, solar radiation forecasting, solar radiation modelling, solar radiation prediction

Adel Mellit

2008-11-01T23:59:59.000Z

330

Atomistic and Rate Theory Modeling of Radiation Damage and ...  

Science Conference Proceedings (OSTI)

... and low neutron cross section, and improvements in mechanical and radiation ... and amorphization trends with grain size, radiation dose, and temperature.

331

A Global Climate Model (GENESIS) with a Land-Surface Transfer Scheme (LSX). Part I: Present Climate Simulation  

Science Conference Proceedings (OSTI)

The present-day climatology of a global climate model (GENESIS Version 1.02) is described. The model includes a land-surface transfer component (LSX) that accounts for the physical effects of vegetation. The atmospheric general circulation model ...

Starley L. Thompson; David Pollard

1995-04-01T23:59:59.000Z

332

Modeling topographic influences on solar radiation: A manual for the SOLARFLUX Model  

DOE Green Energy (OSTI)

SOLARFLUX is a geographical information system (GIS) based computer program (running under ARC/INFO and GRID) that models incoming solar radiation based on surface orientation (slope and aspect), solar angle (azimuth and zenith) as it shifts over time, shadows caused by topographic features, and atmospheric conditions. A convenient user interface allows specification of program parameters including latitude, time interval for simulation, file name of a topographic surface, atmospheric conditions (transmittivity), and file names for output. The user specifies a topographic surface as an array of elevation values (GRID). SOLARFLUX generates five basic types of output: 1) total direct radiation, 2) duration of direct sunlight, 3) total diffuse radiation, 4) skyview factor, and 5) hemispherical viewsheds of sky obstruction for specified surface locations. This manual serves as the comprehensive guide to SOLARFLUX. Included are discussions on modeling insolation on complex surfaces, our theoretical approach, program setup and operation, and a set of applications illustrating characteristics of topographic insolation modeling.

Rich, P.M.; Hetrick, W.A.; Saving, S.C. [Univ. of Kansas, Lawrence, KS (United States)

1995-11-01T23:59:59.000Z

333

Thermal analysis of the Pioneer anomaly: A method to estimate radiative momentum transfer  

SciTech Connect

We present a methodology based on pointlike Lambertian sources that enables one to perform a reliable and comprehensive estimate of the overall thermally induced acceleration of the Pioneer 10 and 11 spacecraft. We show, by developing a sensitivity analysis of the several parameters of the model, that one may achieve a valuable insight into the possible thermal origin of the so-called Pioneer anomaly.

Bertolami, O.; Paramos, J. [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Francisco, F.; Gil, P. J. S. [Departamento de Engenharia Mecanica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2008-11-15T23:59:59.000Z

334

Feedbacks between Eddy Heat Fluxes and Radiative Heating in an Energy-Balance Model  

Science Conference Proceedings (OSTI)

The response of midlatitude temperature structure to changes in radiative forcing is examined in an analytical energy-balance model that includes parameterized eddy heat fluxes and linear radiative heating. The characteristics of heat-...

Lee E. Branscome; Enda O'Brien

1988-02-01T23:59:59.000Z

335

A novel 2-D model approach for the prediction of hourly solar radiation  

Science Conference Proceedings (OSTI)

In this work, a two-dimensional (2-D) representation of the hourly solar radiation data is proposed. The model enables accurate forecasting using image prediction methods. One year solar radiation data that is acquired and collected between August 1, ...

F. Onur Hocaoglu; Nezih Gerek; Mehmet Kurban

2007-06-01T23:59:59.000Z

336

Observations and Modeling of Downward Radiative Fluxes (Solar and Infrared) in Urban/Rural Areas  

Science Conference Proceedings (OSTI)

Pollutants (gaseous and aerosol) contained in urban atmospheres alter radiative fluxes at the surface.Numerous radiative models have been developed, and while few experimental data are available, results areoften contradictory. We have taken ...

Claude Estournel; Raoul Vehil; Daniel Guedalia; Jacques Fontan; Aim Druilhet

1983-01-01T23:59:59.000Z

337

Compendium of Material Composition Data for Radiation Transport Modeling  

Science Conference Proceedings (OSTI)

Introduction Meaningful simulations of radiation transport applications require realistic definitions of material composition and densities. When seeking that information for applications in fields such as homeland security, radiation shielding and protection, and criticality safety, researchers usually encounter a variety of materials for which elemental compositions are not readily available or densities are not defined. Publication of the Compendium of Material Composition Data for Radiation Transport Modeling, Revision 0, in 2006 was the first step toward mitigating this problem. Revision 0 of this document listed 121 materials, selected mostly from the combined personal libraries of staff at the Pacific Northwest National Laboratory (PNNL), and thus had a scope that was recognized at the time to be limited. Nevertheless, its creation did provide a well-referenced source of some unique or hard-to-define material data in a format that could be used directly in radiation transport calculations being performed at PNNL. Moreover, having a single common set of material definitions also helped to standardize at least one aspect of the various modeling efforts across the laboratory by providing separate researchers the ability to compare different model results using a common basis of materials. The authors of the 2006 compendium understood that, depending on its use and feedback, the compendium would need to be revised to correct errors or inconsistencies in the data for the original 121 materials, as well as to increase (per users suggestions) the number of materials listed. This 2010 revision of the compendium has accomplished both of those objectives. The most obvious change is the increased number of materials from 121 to 372. The not-so-obvious change is the mechanism used to produce the data listed here. The data listed in the 2006 document were compiled, evaluated, entered, and error-checked by a group of individuals essentially by hand, providing no library file or mechanism for revising the data in a consistent and traceable manner. The authors of this revision have addressed that problem by first compiling all of the information (i.e., numbers and references) for all the materials into a single database, maintained at PNNL, that was then used as the basis for this document.

McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert

2011-03-04T23:59:59.000Z

338

The Simplest Models of Radiative Neutrino Mass: Excluding Simplified Zee Models and Beyond  

E-Print Network (OSTI)

The complexity of radiative neutrino-mass models can be judged by: (i) whether they require the imposition of ad hoc symmetries, (ii) the number of new multiplets they introduce, and (iii) the number of arbitrary parameters that appear. Adopting the view that the imposition of arbitrary new symmetries is the least appealing approach, the simplest models have two new multiplets and a minimal number of new parameters. With this in mind, we search for the simplest models of radiative neutrino mass. We are lead to two new models, containing a real scalar triplet and a charged scalar doublet (respectively), in addition to the charged singlet scalar considered by Zee [h^+\\sim(1,1,2)]. The new models are essentially simplified versions of the Zee model and appear to be \\emph{the simplest} models of radiative neutrino mass. However, these models are only of pedagogical interest; despite successfully generating nonzero masses, present-day data is sufficient to rule them out. The lessons learned from these models also ...

Law, Sandy S C

2013-01-01T23:59:59.000Z

339

Modeling the free energy surfaces of electron transfer in condensed phases  

E-Print Network (OSTI)

PROOF COPY 509037JCP Modeling the free energy surfaces of electron transfer in condensed phases analytical solution for the ET free energy surfaces demonstrates the following features: i the range of ET reaction coordinates is limited by a one-sided fluctuation band, ii the ET free energies are infinite

Matyushov, Dmitry

340

Modeling of the Output and Transfer Characteristics of Graphene Field-Effect Transistors  

Science Conference Proceedings (OSTI)

We obtain the output and transfer characteristics of graphene field-effect transistors by using the charge-control model for the current, based on the solution of the Boltzmann equation in the field-dependent relaxation time approximation. Closed expressions ...

Brett W. Scott; Jean-Pierre Leburton

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Modelling of heat transfer at glass/mould interface in press and blow forming processes  

Science Conference Proceedings (OSTI)

Numerical models may play an important role in the optimization of the quality of hollow-ware glass articles in glass industry. Due to the complexity of the phenomena involved a coupling between thermal and mechanical aspects is crucial. One of the key ... Keywords: Finite elements, Glass forming, Heat conduction, Heat transfer coefficient, Interface element, Press/blow process

Sbastien Grgoire; Jos M. A. Csar de S; Philippe Moreau; Dominique Lochegnies

2007-08-01T23:59:59.000Z

342

On exact and perturbation solutions to nonlinear equations for heat transfer models  

E-Print Network (OSTI)

We analyze some exact and approximate solutions to nonlinear equations for heat transfer models. We prove that recent results derived from a method based on Lie algebras are either trivial or wrong. We test a simple analytical expression based on the hypervirial theorem and also discuss earlier perturbation results.

Francisco M. Fernndez

2009-11-01T23:59:59.000Z

343

Nuisance Source Population Modeling for Radiation Detection System Analysis  

SciTech Connect

A major challenge facing the prospective deployment of radiation detection systems for homeland security applications is the discrimination of radiological or nuclear 'threat sources' from radioactive, but benign, 'nuisance sources'. Common examples of such nuisance sources include naturally occurring radioactive material (NORM), medical patients who have received radioactive drugs for either diagnostics or treatment, and industrial sources. A sensitive detector that cannot distinguish between 'threat' and 'benign' classes will generate false positives which, if sufficiently frequent, will preclude it from being operationally deployed. In this report, we describe a first-principles physics-based modeling approach that is used to approximate the physical properties and corresponding gamma ray spectral signatures of real nuisance sources. Specific models are proposed for the three nuisance source classes - NORM, medical and industrial. The models can be validated against measured data - that is, energy spectra generated with the model can be compared to actual nuisance source data. We show by example how this is done for NORM and medical sources, using data sets obtained from spectroscopic detector deployments for cargo container screening and urban area traffic screening, respectively. In addition to capturing the range of radioactive signatures of individual nuisance sources, a nuisance source population model must generate sources with a frequency of occurrence consistent with that found in actual movement of goods and people. Measured radiation detection data can indicate these frequencies, but, at present, such data are available only for a very limited set of locations and time periods. In this report, we make more general estimates of frequencies for NORM and medical sources using a range of data sources such as shipping manifests and medical treatment statistics. We also identify potential data sources for industrial source frequencies, but leave the task of estimating these frequencies for future work. Modeling of nuisance source populations is only useful if it helps in understanding detector system performance in real operational environments. Examples of previous studies in which nuisance source models played a key role are briefly discussed. These include screening of in-bound urban traffic and monitoring of shipping containers in transit to U.S. ports.

Sokkappa, P; Lange, D; Nelson, K; Wheeler, R

2009-10-05T23:59:59.000Z

344

A comparison of two heat transfer models for estimating thermal drawdown in Hot Dry Rock reservoirs  

DOE Green Energy (OSTI)

Estimates of thermal drawdown in Hot Dry Rock geothermal systems have been made with two different models of heat transfer from hydraulically fractured reservoir rock blocks to water circulated through the fracture permeability. One model is based on deconvolution of experimental tracer response curves into a network of flowpaths connected in parallel with heat transfer calculated individually in each flowpath. The second model is based on one-dimensional flow through the rock with a block size distribution described as a group of equivalent-radius spheres for which the heat transfer equations can be solved analytically. The two-models were applied to the planned Phase II long-term thermal drawdown experiment at Fenton Hill, NM. The results show good agreement between the two models, with estimates of temperature cooldown from 240/sup 0/C to 150/sup 0/C in a few years depending on selected operation parameters, but with somewhat differing cooldown curve characteristic shapes. Data from the long-term experiment will be helpful in improving the two models.

Robinson, B.A.; Kruger, P.

1988-01-01T23:59:59.000Z

345

Radiation Parameterization for Three-Dimensional Inhomogeneous Cirrus Clouds Applied to ARM Data and Climate Models  

DOE Green Energy (OSTI)

OAK-B135 (a) We developed a 3D radiative transfer model to simulate the transfer of solar and thermal infrared radiation in inhomogeneous cirrus clouds. The model utilized a diffusion approximation approach (four-term expansion in the intensity) employing Cartesian coordinates. The required single-scattering parameters, including the extinction coefficient, single-scattering albedo, and asymmetry factor, for input to the model, were parameterized in terms of the ice water content and mean effective ice crystal size. The incorporation of gaseous absorption in multiple scattering atmospheres was accomplished by means of the correlated k-distribution approach. In addition, the strong forward diffraction nature in the phase function was accounted for in each predivided spatial grid based on a delta-function adjustment. The radiation parameterization developed herein is applied to potential cloud configurations generated from GCMs to investigate broken clouds and cloud-overlapping effects on the domain-averaged heating rate. Cloud inhomogeneity plays an important role in the determination of flux and heating rate distributions. Clouds with maximum overlap tend to produce less heating than those with random overlap. Broken clouds show more solar heating as well as more IR cooling as compared to a continuous cloud field (Gu and Liou, 2001). (b) We incorporated a contemporary radiation parameterization scheme in the UCLA atmospheric GCM in collaboration with the UCLA GCM group. In conjunction with the cloud/radiation process studies, we developed a physically-based cloud cover formation scheme in association with radiation calculations. The model clouds were first vertically grouped in terms of low, middle, and high types. Maximum overlap was then used for each cloud type, followed by random overlap among the three cloud types. Fu and Liou's 1D radiation code with modification was subsequently employed for pixel-by-pixel radiation calculations in the UCLA GCM. We showed that the simulated cloud cover and OLR fields without special tuning are comparable to those of ISCCP dataset and the results derived from radiation budget experiments. Use of the new radiation and cloud schemes enhances the radiative warming in the middle to upper tropical troposphere and alleviates the cold bias in the UCLA atmospheric GCM. We also illustrated that ice crystal size and cloud inhomogeneous are significant factors affecting the radiation budgets at the top of the atmosphere and the surface (Gu et al. 2003). (c) An innovative approach has been developed to construct a 3D field of inhomogeneous clouds in general and cirrus in particular in terms of liquid/ice water content and particle size on the basis of a unification of satellite and ground-based cloud radar data. Satellite remote sensing employing the current narrow-band spectro-radiometers has limitation and only the vertically integrated cloud parameters (optical depth and mean particle size) can be determined. However, by combining the horizontal cloud mapping inferred from satellites with the vertical structure derived from the profiling Doppler cloud radar, a 3D cloud field can be constructed. This represents a new conceptual approach to 3D remote sensing and imaging and offers a new perspective in observing the cloud structure. We applied this novel technique to AVHRR/NOAA satellite and mm-wave cloud radar data obtained from the ARM achieve and assessed the 3D cirrus cloud field with the ice crystal size distributions independently derived from optical probe measurements aboard the University of North Dakota Citation. The retrieved 3D ice water content and mean effective ice crystal size involving an impressive cirrus cloud occurring on April 18, 1997, are shown to be comparable to those derived from the analysis of collocated and coincident in situ aircraft measurements (Liou et al. 2002). (d) Detection of thin cirrus with optical depths less than 0.5, particularly those occurring i n the tropics remains a fundamental problem in remote sensing. We developed a new detection scheme for the

Kuo-Nan Liou

2003-12-29T23:59:59.000Z

346

Fundamental Drop Dynamics and Mass Transfer Experiments to Support Solvent Extraction Modeling Efforts  

SciTech Connect

In support of the Nuclear Energy Advanced Modeling Simulation Safeguards and Separations (NEAMS SafeSep) program, the Idaho National Laboratory (INL) worked in collaboration with Los Alamos National Laboratory (LANL) to further a modeling effort designed to predict mass transfer behavior for selected metal species between individual dispersed drops and a continuous phase in a two phase liquid-liquid extraction (LLE) system. The purpose of the model is to understand the fundamental processes of mass transfer that occur at the drop interface. This fundamental understanding can be extended to support modeling of larger LLE equipment such as mixer settlers, pulse columns, and centrifugal contactors. The work performed at the INL involved gathering the necessary experimental data to support the modeling effort. A custom experimental apparatus was designed and built for performing drop contact experiments to measure mass transfer coefficients as a function of contact time. A high speed digital camera was used in conjunction with the apparatus to measure size, shape, and velocity of the drops. In addition to drop data, the physical properties of the experimental fluids were measured to be used as input data for the model. Physical properties measurements included density, viscosity, surface tension and interfacial tension. Additionally, self diffusion coefficients for the selected metal species in each experimental solution were measured, and the distribution coefficient for the metal partitioning between phases was determined. At the completion of this work, the INL has determined the mass transfer coefficient and a velocity profile for drops rising by buoyancy through a continuous medium under a specific set of experimental conditions. Additionally, a complete set of experimentally determined fluid properties has been obtained. All data will be provided to LANL to support the modeling effort.

Kristi Christensen; Veronica Rutledge; Troy Garn

2011-09-01T23:59:59.000Z

347

Information transfer model of natural processes: from the ideal gas law to the K effect  

E-Print Network (OSTI)

Information theory provides shortcuts which allow to deal with complex systems. The basic idea one uses for this purpose is the maximum entropy principle developed by Jaynes. However, an extensions of this maximum entropy principle to systems far from thermal equilibrium or even to non-physical systems is problematic because it requires an adequate choice of constraints. In this paper we apply the information theory in an even more abstract way and propose an information transfer model of natural processes which does not require any choice of adequate constraints. It is, therefore, directly applicable to systems far from thermal equilibrium and to non-physical systems/processes (e.g. biological processes and economical processes). We demonstrate the validity and the applicability of the information transfer concept by three well understood physical processes. As an interesting astronomical application we will show that the information transfer concept allows to rationalize and to quantify the K effect.

P. Fielitz; G. Borchardt

2009-05-05T23:59:59.000Z

348

A Comparison of Three Different Modeling Strategies for Evaluating Cloud and Radiation Parameterizations  

Science Conference Proceedings (OSTI)

Parallel simulations of clouds and radiation fields by a single-column model (SCM), a regional circulation model, and a global circulation model (GCM), each using the same treatment of all physical processes and approximately the same spatial ...

Steven J. Ghan; L. Ruby Leung; James McCaa

1999-09-01T23:59:59.000Z

349

A one-dimensional material transfer model for HECTR version 1. 5  

DOE Green Energy (OSTI)

HECTR (Hydrogen Event Containment Transient Response) is a lumped-parameter computer code developed for calculating the pressure-temperature response to combustion in a nuclear power plant containment building. The code uses a control-volume approach and subscale models to simulate the mass, momentum, and energy transfer occurring in the containment during a loss-of-collant-accident (LOCA). This document describes one-dimensional subscale models for mass and momentum transfer, and the modifications to the code required to implement them. Two problems were analyzed: the first corresponding to a standard problem studied with previous HECTR versions, the second to experiments. The performance of the revised code relative to previous HECTR version is discussed as is the ability of the code to model the experiments. 8 refs., 5 figs., 3 tabs.

Geller, A.S.; Wong, C.C.

1991-08-01T23:59:59.000Z

350

Estimation of Sensible and Latent Heat Fluxes from Soil Surface Temperature Using a Linear Air-Land Heat Transfer Model  

Science Conference Proceedings (OSTI)

The authors present a linearized model of the heat transfer between the soil layer and the atmosphere. Using this model, the moisture availability at the surface can be estimated from the diurnal variations of the soil surface temperature and ...

Fujio Kimura; Yugo Shimizu

1994-04-01T23:59:59.000Z

351

First-principles models for radiation damage in D-T fusion power ...  

Science Conference Proceedings (OSTI)

On-Site Speaker (Planned), Duc Nguyen-Manh. Abstract Scope, We review current work on first-principles modelling of radiation defects in bcc iron-based...

352

Modeling of solid-side mass transfer in desiccant particle beds  

DOE Green Energy (OSTI)

A model is proposed for heat and mass transfer in a packed bed of desiccant particles and accounts for both Knudsen and surface diffusion within the particles. Using the model, predictions are made for the response of thin beds of silica gel particles to a step change in air inlet conditions compared to mental results. The predictions are found to be satisfactory and, in general, superior to those of pseudogas-side controlled models commonly used for the design of desiccant dehumidifiers for solar air conditioning application.

Pesaran, A.A.; Mills, A.F.

1984-02-01T23:59:59.000Z

353

Daily radiation model for use in the simulation of passive solar buildings  

DOE Green Energy (OSTI)

A model is presented to characterize solar radiation with just three input parameters for each day. This compressed daily radiation data may be used in place of hourly data in simulations of passive solar buildings. This method is tested with the SUNCAT passive simulation. Global horizontal and direct normal radiation data are input using the compressed daily form instead of by hour. Simulation results are found to be comparable to results based on hourly radiation data.

Sillman, S.; Wortman, D.

1981-04-01T23:59:59.000Z

354

The 2728 October 1986 FIRF IFO Cirrus Case Study: Comparison of Radiative Transfer Theory with Observations by Satellite and Aircraft  

Science Conference Proceedings (OSTI)

Observations of cirrus and altocumulus clouds during the First International Satellite Cloud Climatology Project Regional Experiment (FIRE) are compared to theoretical models of cloud radiative properties. Three tests are performed. First, ...

Bruce A. Wielicki; J.T. Suttles; Andrew J. Heymsfield; Ronald M. Welch; James D. Spinhirne; Man-Li C. Wu; David O'C. Starr; Lindsay Parker; Robert F. Arduini

1990-11-01T23:59:59.000Z

355

An Ultralight Aircraft as Platform for Research in the Lower Troposphere: System Performance and First Results from Radiation Transfer Studies in Stratiform Aerosol Layers and Broken Cloud Conditions  

Science Conference Proceedings (OSTI)

The ultraviolet actinic radiation flux governing the photochemical reactions in the atmosphere is dependent on the optical properties of atmospheric aerosols and reflective surfaces of ground and clouds. Theoretical models exist for horizontal ...

Wolfgang Junkermann

2001-06-01T23:59:59.000Z

356

The Influence of Radiative Transfer on the Mass and Heat Budgets of Ice Crystals Failing in the Atmosphere  

Science Conference Proceedings (OSTI)

A theoretical study was carried out to investigate the effect of radiative heating and cooling on the mass and heat budgets of an ice crystal. Equations describing the radiative budget of an ice crystal were derived and particle absorption ...

Graeme L. Stephens

1983-07-01T23:59:59.000Z

357

Application Of A Spherical-Radial Heat Transfer Model To Calculate  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Application Of A Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Application Of A Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Details Activities (0) Areas (0) Regions (0) Abstract: This paper presents estimates of the undisturbed formation temperatures in a geothermal exploration well drilled in the Ceboruco area in the western part of the Mexican Volcanic Belt. The method used assumes

358

Whole-Building Energy Simulation with a Three-Dimensional Ground-Coupled Heat Transfer Model: Preprint  

DOE Green Energy (OSTI)

A three-dimensional, finite-element, heat-transfer computer program was developed to study ground-coupled heat transfer from buildings. It was used in conjunction with the SUNREL whole-building energy simulation program to analyze ground-coupled heat transfer from buildings, and the results were compared with the simple ground-coupled heat transfer models used in whole-building energy simulation programs. The detailed model provides another method of testing and refining the simple models and analyzing complex problems. This work is part of an effort to improve the analysis of the ground-coupled heat transfer in building energy simulation programs. The output from this detailed model and several others will form a set of reference results for use with the BESTEST diagnostic procedure. We anticipate that the results from the work will be incorporated into ANSI/ASHRAE 140-2001, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs.

Deru, M.; Judkoff, R.; Neymark, J.

2002-08-01T23:59:59.000Z

359

Environmental radiation dose criteria and assessment: pathway modeling and surveillance  

SciTech Connect

From nuclear science symposium; San Francisco, California, USA (14 Nov 1973). The controversy in recent years over the extent of the risk to the public from environmental radioactivity attributable to nuclear facilities (in particular nuclear power plants and fuel reprocessing facilities) has resulted in a lowering of previously acceptable environmental radiation levels. The proposal by the AEC to limit effluents from light-water-cooled nuclear reactors so that the exposure of any individual in the public would not exceed 5 mR/yr, and the pronouncement by the BEIR Committee that the current environmental radiation protection guides are unnecessarily high, are illustrative. In turn the AEC has issued a Safety Guide calling for considerable refinement in the measuring and reporting of effluents from nuclear power plants, and has only recently issued a counterpart dealing with the measuring and reporting of radioactivity in the environs of nuclear power plants. The EPA has also recently issued a guide for the surveillance of environmental radioactivity. Currently, power reactor operators are being required by the AEC Regulatory Staff to conduct detailed, sensitive environmental surveillance. Much of this appears to be based on extremely conservative assumptions throughout, including doseeffect relationships, exposure situations, pathway models, reconcentration factors and intakes, which cannot be substantiated when examined in the light of current experience in the vicinity of existing power reactors. The expenditures occasioned by the required additional in-plant features necessary to meet the currently proposed effluent release criteria appear difficult to justify on a reasonable basis. Environmental monitoring at the proposed concentration limits appear even more excessive in terms of dollars per man-rem of potential dose commitment. (auth)

Hull, A.P.

1973-01-01T23:59:59.000Z

360

General Circulation Model Calculations of the Direct Radiative Forcing by Anthropogenic Sulfate and Fossil-Fuel Soot Aerosol  

Science Conference Proceedings (OSTI)

A new radiation code within a general circulation model is used to assess the direct solar and thermal radiative forcing by sulfate aerosol of anthropogenic origin and soot aerosol from fossil-fuel burning. The radiative effects of different ...

J. M. Haywood; D. L. Roberts; A. Slingo; J. M. Edwards; K. P. Shine

1997-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Literature Review and Assessment of Plant and Animal Transfer Factors Used in Performance Assessment Modeling  

Science Conference Proceedings (OSTI)

A literature review and assessment was conducted by Pacific Northwest National Laboratory (PNNL) to update information on plant and animal radionuclide transfer factors used in performance-assessment modeling. A group of 15 radionuclides was included in this review and assessment. The review is composed of four main sections, not including the Introduction. Section 2.0 provides a review of the critically important issue of physicochemical speciation and geochemistry of the radionuclides in natural soil-water systems as it relates to the bioavailability of the radionuclides. Section 3.0 provides an updated review of the parameters of importance in the uptake of radionuclides by plants, including root uptake via the soil-groundwater system and foliar uptake due to overhead irrigation. Section 3.0 also provides a compilation of concentration ratios (CRs) for soil-to-plant uptake for the 15 selected radionuclides. Section 4.0 provides an updated review on radionuclide uptake data for animal products related to absorption, homeostatic control, approach to equilibration, chemical and physical form, diet, and age. Compiled transfer coefficients are provided for cows milk, sheeps milk, goats milk, beef, goat meat, pork, poultry, and eggs. Section 5.0 discusses the use of transfer coefficients in soil, plant, and animal modeling using regulatory models for evaluating radioactive waste disposal or decommissioned sites. Each section makes specific suggestions for future research in its area.

Robertson, David E.; Cataldo, Dominic A.; Napier, Bruce A.; Krupka, Kenneth M.; Sasser, Lyle B.

2003-07-20T23:59:59.000Z

362

The Effect of Clouds on the Earth's Solar and Infrared Radiation Budgets  

Science Conference Proceedings (OSTI)

The effect of global cloudiness on the solar and infrared components of the earth's radiation balance is studied in general circulation model experiments. A wintertime simulation is conducted in which the cloud radiative transfer calculations use ...

Gerald F. Herman; Man-Li C. Wu; Winthrop T. Johnson

1980-06-01T23:59:59.000Z

363

The CERES/ARM/GEWEX Experiment (CAGEX) for the Retrieval of Radiative Fluxes with Satellite Data  

Science Conference Proceedings (OSTI)

Results from a temporally intensive, limited area, radiative transfer model experiment are on-line for investigating the vertical profile of shortwave and longwave radiative fluxes from the surface to the top of the atmosphere (TOA). The CERES/...

Thomas P. Charlock; Timothy L. Alberta

1996-11-01T23:59:59.000Z

364

Radiative Properties of Cirrus Clouds in the Infrared Region  

Science Conference Proceedings (OSTI)

A multiple-scattering radiative transfer model is employed to evaluate the 11 ?m and the broad-band infrared (IR) fluxes, cooling rates and emittances in model cirrus clouds for a number of standard vertical atmospheric profiles of temperature ...

Graeme L. Stephens

1980-02-01T23:59:59.000Z

365

A Simple Physical Model to Estimate Incident Solar Radiation at the Surface from GOES Satellite Data  

Science Conference Proceedings (OSTI)

We present a model designed to estimate the incident solar radiation at the suface from GOES satellite brightness measurements in clear and cloudy conditions. In this simple physical model, the effect of Rayleigh scattering is taken into account. ...

Catherine Gautier; Georges Diak; Serge Masse

1980-08-01T23:59:59.000Z

366

Implementation of a Semiphysical Model for Examining Solar Radiation in the Midwest  

Science Conference Proceedings (OSTI)

A semiphysical solar radiation (SR) model is implemented to generate a new historical daily SR database for 53 locations in nine Midwestern and six adjacent states (available from the Midwestern Climate Center). This model estimates daily SR ...

Mary Schoen Petersen; Peter J. Lamb; Kenneth E. Kunkel

1995-09-01T23:59:59.000Z

367

Reproducibility by Climate Models of Cloud Radiative Forcing Associated with Tropical Convection  

Science Conference Proceedings (OSTI)

In this study, cloud radiative forcing (CRF) associated with convective activity over tropical oceans is analyzed for monthly mean data from twentieth-century simulations of 18 climate models participating in phase 3 of the Coupled Model ...

Hiroki Ichikawa; Hirohiko Masunaga; Yoko Tsushima; Hiroshi Kanzawa

2012-02-01T23:59:59.000Z

368

Radiative Forcing of Saharan Dust: GOCART Model Simulations Compared with ERBE Data  

Science Conference Proceedings (OSTI)

This study uses information on Saharan aerosol from a dust transport model to calculate radiative forcing values. The transport model is driven by assimilated meteorological fields from the Goddard Earth Observing System Data Assimilation System. ...

Clark J. Weaver; Paul Ginoux; N. Christina Hsu; Ming-Dah Chou; Joanna Joiner

2002-02-01T23:59:59.000Z

369

Determination of Extratropical Tropopause Height in an Idealized Gray Radiation Model  

Science Conference Proceedings (OSTI)

This paper investigates the mechanisms that determine the extratropical tropopause height, extending previous results with a Newtonian cooling model. A primitive equation model forced by a meridional gradient of incoming solar radiation, with the ...

Pablo Zurita-Gotor; Geoffrey K. Vallis

2013-07-01T23:59:59.000Z

370

Adjustment to Radiative Forcing in a Simple Coupled OceanAtmosphere Model  

Science Conference Proceedings (OSTI)

This study calculates the adjustment to radiative forcing in a simple model of a mixed layer ocean coupled to the overlying atmosphere. One application of the model is to calculate how dust aerosols perturb the temperature of the atmosphere and ...

R. L. Miller

2012-11-01T23:59:59.000Z

371

Radiators  

SciTech Connect

A heat-exchange radiator is connected to a fluid flow circuit by a connector which provides one member of an interengageable spigot and socket pair for push-fit, fluid-tight, engagement between the connector and the radiator, with latching formations at least one of which is resilient. Preferably the connector carries the spigot which tapers and engages with a socket of corresponding shape, the spigot carrying an O-ring seal and either latching fingers or a resilient latching circlip.

Webster, D. M.

1985-07-30T23:59:59.000Z

372

An Experimental Implementation of Oblivious Transfer in the Noisy Storage Model  

E-Print Network (OSTI)

Cryptography's importance in our everyday lives continues to grow in our increasingly digital world. Oblivious transfer (OT) has long been a fundamental and important cryptographic primitive since it is known that general two-party cryptographic tasks can be built from this basic building block. Here we show the experimental implementation of a 1-2 random oblivious transfer (ROT) protocol by performing measurements on polarization-entangled photon pairs in a modified entangled quantum key distribution system, followed by all of the necessary classical post-processing including one-way error correction. We successfully exchange a 1,366 bits ROT string in ~3 min and include a full security analysis under the noisy storage model, accounting for all experimental error rates and finite size effects. This demonstrates the feasibility of using today's quantum technologies to implement secure two-party protocols.

C. Erven; N. Ng; N. Gigov; R. Laflamme; S. Wehner; G. Weihs

2013-08-23T23:59:59.000Z

373

Testing a Model of IR Radiative Losses: Preprint  

DOE Green Energy (OSTI)

Thermopile pyranometers exhibit IR radiative losses that affect global and diffuse shortwave measurements made with first class thermopile based instruments. Pyrgeometers can be used to measure the sky temperature and are used to calculate the pyranometer?s IR radiative losses.

Vignola, F.; Long, C. N.; Reda, I.

2009-08-01T23:59:59.000Z

374

Toward a Minimal Representation of Aerosols in Climate Models: Comparative Decomposition of Aerosol Direct, Semidirect, and Indirect Radiative Forcing  

SciTech Connect

The authors have decomposed the anthropogenic aerosol radiative forcing into direct contributions from each aerosol species to the planetary energy balance through absorption and scattering of solar radiation, indirect effects of anthropogenic aerosol on solar and infrared radiation through droplet and crystal nucleation on aerosol, and semidirect effects through the influence of solar absorption on the distribution of clouds. A three-mode representation of the aerosol in version 5.1 of the Community Atmosphere Model (CAM5.1) yields global annual mean radiative forcing estimates for each of these forcing mechanisms that are within 0.1 W m2 of estimates using a more complex seven-mode representation that distinguishes between fresh and aged black carbon and primary organic matter. Simulating fresh black carbon particles separately from internally mixed accumulation mode particles is found to be important only near fossil fuel sources. In addition to the usual large indirect effect on solar radiation, this study finds an unexpectedly large positive longwave indirect effect (because of enhanced cirrus produced by homogenous nucleation of ice crystals on anthropogenic sulfate), small shortwave and longwave semidirect effects, and a small direct effect (because of cancelation and interactions of direct effects of black carbon and sulfate). Differences between the threemode and seven-mode versions are significantly larger (up to 0.2 W m2) when the hygroscopicity of primary organic matter is decreased from 0.1 to 0 and transfer of the primary carbonaceous aerosol to the accumulation mode in the seven-mode version requires more hygroscopic material coating the primary particles. Radiative forcing by cloudborne anthropogenic black carbon is only 20.07 W m2.

Ghan, Steven J.; Liu, Xiaohong; Easter, Richard C.; Zaveri, Rahul A.; Rasch, Philip J.; Yoon, Jin-Ho; Eaton, Brian

2012-10-01T23:59:59.000Z

375

A multiple-relaxation-time lattice Boltzmann model for convection heat transfer in porous media  

E-Print Network (OSTI)

In this paper, a multiple-relaxation-time (MRT) lattice Boltzmann (LB) model is developed for simulating convection heat transfer in porous media at the representative elementary volume scale. In the model, a MRT-LB equation is used to simulate the flow field, while another MRT-LB equation is employed to simulate the temperature field. The effect of the porous media is considered by introducing the porosity into the equilibrium moments, and adding a forcing term to the MRT-LB equation of the flow field in the moment space. The proposed MRT-LB model is validated by numerical simulations of several two-dimensional convection problems in porous media. The numerical results predicted by the present MRT-LB model agree well with those reported in the literature.

Q. Liu; Y. L. He; Q. Li

2013-08-09T23:59:59.000Z

376

The Effect of Directional Radiation Models on the Interpretation of Earth Radiation Budget Measurements  

Science Conference Proceedings (OSTI)

A parameter estimation technique is presented to estimate the radiative flux density distribution over the earn from a set of radiometer measurements at satellite altitude. The technique analyzes measurements from a wide field of view, horizon to ...

Richard N. Green

1980-10-01T23:59:59.000Z

377

The Nocturnal Boundary Layer: Model Calculations Compared with Observations  

Science Conference Proceedings (OSTI)

The structure and evolution of the nocturnal boundary layer (NBL) is simulated using a model which includes the transfer of energy by radiation and turbulence. The radiation scheme is an accurate narrow band model which simulates the absorption ...

Stephen A. Tjemkes; Peter G. Duynkergke

1989-03-01T23:59:59.000Z

378

Turbulent Transfer Coefficients and Calculation of Air Temperature inside Tall Grass Canopies in LandAtmosphere Schemes for Environmental Modeling  

Science Conference Proceedings (OSTI)

A method for estimating profiles of turbulent transfer coefficients inside a vegetation canopy and their use in calculating the air temperature inside tall grass canopies in land surface schemes for environmental modeling is presented. The ...

D. T. Mihailovic; K. Alapaty; B. Lalic; I. Arsenic; B. Rajkovic; S. Malinovic

2004-10-01T23:59:59.000Z

379

Radiative Importance of ThinŽ Liquid Water Clouds  

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

Program Program Accomplishments of the Instantaneous Radiative Flux (IRF) Working Group August 2006 AERI Observations at Southern Great Plains Improve Infrared Radiative Transfer Models Turner et al., JAS, 2004 * AERI observations used to evaluate clear sky IR radiative transfer models * Long-term comparisons have improved - Spectral line database parameters - Water vapor continuum absorption models * Reduced errors in computation of downwelling radiative IR flux by approx 4; current uncertainty is on the order of 1.5 W/m 2 AERI - (Pre-ARM Model) AERI - (Model in 2003) 1 RU = 1 mW / (m 2 sr cm -1 ) Excellent Agreement in Clear Sky Shortwave Radiative Transfer Between Obs and Calcs Shortwave Flux Bias (Solid) Shortwave Flux RMS (Hatched) W m -2 * Comparison of shortwave radiative flux at the surface

380

Posters A One-Dimensional Radiative Convective Model with Detailed Cloud Microphysics  

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

5 5 Posters A One-Dimensional Radiative Convective Model with Detailed Cloud Microphysics J. Simmons, O. Lie-Svendsen, and K. Stamnes Geophysical Institute University of Alaska Fairbanks, Alaska The Arctic is a key element in determining the radiation budget of the earth. Within the polar regions, the net radiation (incoming solar radiation minus outgoing infrared radiation) is negative. To understand the role this energy deficit plays in the overall radiation budget, one must examine the prevalent atmospheric features of the Arctic. One such feature is a persistent layer of low-altitude, stratiform clouds found over the central Arctic predominantly from April to September (Tsay et al. 1984). These Arctic stratus clouds (ASC) modulate the earth's radiation budget

Note: This page contains sample records for the topic "radiation transfer models" 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

A Study on the Runaway Greenhouse Effect with a One-Dimensional RadiativeConvective Equilibrium Model  

Science Conference Proceedings (OSTI)

A simple one-dimensional radiativeconvective equilibrium model is used to investigate the relationship between the surface temperature and the outgoing infrared radiation at the top of the atmosphere. The model atmosphere has a gray infrared ...

Shinichi Nakajima; Yoshi-Yuki Hayashi; Yutaka Abe

1992-12-01T23:59:59.000Z

382

Normal Tissue Complication Probability Modeling of Radiation-Induced Hypothyroidism After Head-and-Neck Radiation Therapy  

Science Conference Proceedings (OSTI)

Purpose: To determine the dose-response relationship of the thyroid for radiation-induced hypothyroidism in head-and-neck radiation therapy, according to 6 normal tissue complication probability models, and to find the best-fit parameters of the models. Methods and Materials: Sixty-five patients treated with primary or postoperative radiation therapy for various cancers in the head-and-neck region were prospectively evaluated. Patient serum samples (tri-iodothyronine, thyroxine, thyroid-stimulating hormone [TSH], free tri-iodothyronine, and free thyroxine) were measured before and at regular time intervals until 1 year after the completion of radiation therapy. Dose-volume histograms (DVHs) of the patients' thyroid gland were derived from their computed tomography (CT)-based treatment planning data. Hypothyroidism was defined as increased TSH (subclinical hypothyroidism) or increased TSH in combination with decreased free thyroxine and thyroxine (clinical hypothyroidism). Thyroid DVHs were converted to 2 Gy/fraction equivalent doses using the linear-quadratic formula with {alpha}/{beta} = 3 Gy. The evaluated models included the following: Lyman with the DVH reduced to the equivalent uniform dose (EUD), known as LEUD; Logit-EUD; mean dose; relative seriality; individual critical volume; and population critical volume models. The parameters of the models were obtained by fitting the patients' data using a maximum likelihood analysis method. The goodness of fit of the models was determined by the 2-sample Kolmogorov-Smirnov test. Ranking of the models was made according to Akaike's information criterion. Results: Twenty-nine patients (44.6%) experienced hypothyroidism. None of the models was rejected according to the evaluation of the goodness of fit. The mean dose model was ranked as the best model on the basis of its Akaike's information criterion value. The D{sub 50} estimated from the models was approximately 44 Gy. Conclusions: The implemented normal tissue complication probability models showed a parallel architecture for the thyroid. The mean dose model can be used as the best model to describe the dose-response relationship for hypothyroidism complication.

Bakhshandeh, Mohsen [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)] [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)] [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mahdavi, Seied Rabi Mehdi [Department of Medical Physics, Faculty of Medical Sciences, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)] [Department of Medical Physics, Faculty of Medical Sciences, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Nikoofar, Alireza; Vasheghani, Maryam [Department of Radiation Oncology, Hafte-Tir Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)] [Department of Radiation Oncology, Hafte-Tir Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Kazemnejad, Anoshirvan [Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)] [Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

2013-02-01T23:59:59.000Z

383

ICRCCM Phase 2: Verification and calibration of radiation codes in climate models  

SciTech Connect

Following the finding by the InterComparison of Radiation Codes used in Climate Models (ICRCCM) of large differences among fluxes predicted by sophisticated radiation models that could not be sorted out because of the lack of a set of accurate atmospheric spectral radiation data measured simultaneously with the important radiative properties of the atmosphere, our team of scientists proposed to remedy the situation by carrying out a comprehensive program of measurement and analysis called SPECTRE (Spectral Radiance Experiment). SPECTRE will establish an absolute standard against which to compare models, and will aim to remove the hidden variables'' (unknown humidities, aerosols, etc.) which radiation modelers have invoked to excuse disagreements with observation. The data to be collected during SPECTRE will form the test bed for the second phase of ICRCCM, namely verification and calibration of radiation codes used in climate models. This should lead to more accurate radiation models for use in parameterizing climate models, which in turn play a key role in the prediction of trace-gas greenhouse effects.

Ellingson, R.G.; Wiscombe, W.J.; Murcray, D.; Smith, W.; Strauch, R.

1991-01-01T23:59:59.000Z

384

Runaway Greenhouse Effect in a Semigray RadiativeConvective Model  

Science Conference Proceedings (OSTI)

The effects of the nongray absorption (i.e., atmospheric opacity varying with wavelength) on the possible upper bound of the outgoing longwave radiation (OLR) emitted by a planetary atmosphere have been examined. This analysis is based on the ...

T. Pujol; G. R. North

2002-10-01T23:59:59.000Z

385

A Solar Radiation Model for Use in Climate Studies  

Science Conference Proceedings (OSTI)

A solar radiation routine has been developed for use in climate studies. It includes the absorption and scattering due to ozone, water vapor, oxygen, carbon dioxide, clouds, and aerosols. Rayleigh scattering is also included. The UV and visible ...

Ming-Dah Chou

1992-05-01T23:59:59.000Z

386

Low Dose Radiation Research Program: Mechanistic Modeling of...  

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

Laboratory Why This Project? Cells that are directly exposed to low doses of ionizing radiation may experience DNA damage. Cells which happen to be in the vicinity of the exposed...

387

Comparison between Model Simulations and Measurements of Hyperspectral Far- infrared Radiation from FIRST during the RHUBC-II Campaign  

E-Print Network (OSTI)

Surface downward far-infrared (far-IR) spectra were collected from NASAs Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument from August to October 2009 at an altitude of 5.4 km near the summit of Cerro Toco, Chile. This region is known for its dry, cold, and dominantly clear atmosphere, which is optimal for studying the effects, that water vapor and cirrus clouds have on the far-IR. Comparisons with Line-By-Line Discrete Ordinants Radiative Transfer model, LBLDIS, show that FIRST observes the very fine spectral structure in the far-IR with differences as small as +/- 0.7% for both clear-sky and cloudy-sky simulations. Clear sky model analysis demonstrated the greatest sensitivity to atmospheric conditions is between 300 and 500 cm-1. The cloudy-sky simulations demonstrated that the far-IR radiation has minimal sensitivity to cloud particle effective radius, yet is very sensitive to cloud optical thickness at wavenumbers between 400 - 600 cm-1. In fact, cirrus optical thickness found to be inferred from the brightness temperature differences at 250 and 559.5 cm-1. Aerosols proved to reduce downwelling radiance by half that a clear-sky would emit, but had little effect on the total far-IR radiative forcing. Furthermore, these far-IR measurements open a new window to understanding the radiative impacts of various atmospheric constituents such as water vapor and clouds, and to understanding and modeling the Earths climate and energy budget.

Baugher, Elizabeth

2011-12-01T23:59:59.000Z

388

Validated, unified model for optics and heat transfer in line-axis concentrating solar energy collectors  

SciTech Connect

A rigorous numerical simulation model for the prediction of the combined optical and thermofluid behaviour of line-axis concentrating solar energy collectors combines two-dimensional steady-state finite element analysis of convective heat transfer and ray-trace techniques. The optical analysis considers both direct and diffuse insolation components and is therefore useful for the analysis of compound parabolic concentrating collectors. Experiments using Mach-Zehnder interferometry indicate a parametric range for which such a two-dimensional representation is valid.

Eames, P.C.; Norton, B. (Univ. of Ulster (United Kingdom))

1993-04-01T23:59:59.000Z

389

Three-Dimensional Modeling of Shape Memory Polymers Considering Finite Deformations and Heat Transfer  

E-Print Network (OSTI)

Shape memory polymers (SMPs) are a relatively new class of active materials that can store a temporary shape and return to the original configuration upon application of a stimulus such as temperature. This shape changing ability has led to increased interest in their use for biomedical and aerospace applications. A major challenge, however, in the advancement of these applications is the ability to accurately predict the material behavior for complex geometries and boundary conditions. This work addresses this challenge by developing an experimentally calibrated and validated constitutive model that is implemented as a user material subroutine in Abaqus ? a commercially available finite element software package. The model is formulated in terms of finite deformations and assumes the SMP behaves as a thermoelastic material, for which the response is modeled using a compressible neo-Hookean constitutive equation. An internal state variable, the glassy volume fraction, is introduced to account for the phase transformation and associated stored deformation upon cooling from the rubbery phase to the glassy phase and subsequently recovered upon heating. The numerical implementation is performed such that a system of equations is solved using a Newton-Raphson method to find the updated stress in the material. The conductive heat transfer is incorporated through solving Fourier's law simultaneously with the constitutive equations. To calibrate and validate the model parameters, thermomechanical experiments are performed on an amorphous, thermosetting polyurethane shape memory polymer. Strains of 10-25% are applied and both free recovery (zero load) and constrained displacement recovery boundary conditions are considered for each value of applied strain. Using the uniaxial experimental data, the model is then calibrated and compared to the 1-D experimental results. The validated finite element analysis tool is then used to model biomedical devices, including cardiovascular tubes and thrombectomy devices, fabricated from shape memory polymers. The effects of heat transfer and complex thermal boundary conditions are evaluated using coupled thermal-displacement analysis, for which the thermal material properties were experimentally calibrated.

Volk, Brent 1985-

2012-12-01T23:59:59.000Z

390

The OceanLandAtmosphere Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation  

Science Conference Proceedings (OSTI)

This work continues the presentation and evaluation of the OceanLandAtmosphere Model (OLAM), focusing on the models ability to represent radiation and precipitation. OLAM is a new, state-of-the-art earth system model, capable of user-specified ...

David Medvigy; Robert L. Walko; Martin J. Otte; Roni Avissar

2010-05-01T23:59:59.000Z

391

Study on development of education model and its evaluation system for radiation safety  

E-Print Network (OSTI)

As one of the detailed action strategy of multi object preparedness for strengthening of radiation safety management by MOST, this project was performed, in order to promote the safety culture for user and radiation worker through effective education program. For the prevention of radiological accident and effective implementation of radiation safety education and training, this project has been carried out the development of education model and its evaluation system on radiation safety. In the development of new education model, education course was classified; new and old radiation worker, temporary worker, lecturer and manager. The education model includes the contents of expanding the education opportunity and workplace training. In the development of evaluation system, the recognition criteria for commission-education institute and inside-education institute which should establish by law were suggested for evaluation program. The recognition criteria contains classification, student, method, facilities, ...

Seo, K W; Nam, Y M

2002-01-01T23:59:59.000Z

392

Shortwave Radiation Budget of the Southern Hemisphere Using ISCCP C2 and NCEPNCAR Climatological Data  

Science Conference Proceedings (OSTI)

The seasonal shortwave radiation budget at the surface of the Southern Hemisphere was estimated, for 10 latitudinal zones, using a radiative transfer model with long-term mean monthly climatological data from the International Satellite Cloud ...

N. Hatzianastassiou; I. Vardavas

2001-11-01T23:59:59.000Z

393

A Dislocation-Based Model for Design of Radiation-Tolerant ...  

Science Conference Proceedings (OSTI)

Unexpected interfaces for extreme radiation environment are discussed. ... Atomic-Scale Modeling of the Mobility of Boundaries of Deformation Twins in Alpha-Iron ... Characterization of Reaction Layers in Mn1.5Co1.5O4 Coated Fuel Cell ... Possible Radiation Damage Healing Mechanism under Fusion Reactor Conditions.

394

A simplified physical model for assessing solar radiation over Brazil using GOES 8 visible imagery  

E-Print Network (OSTI)

A simplified physical model for assessing solar radiation over Brazil using GOES 8 visible imagery; published 30 January 2004. [1] Solar radiation assessment by satellite is constrained by physical.4 and 1.3 MJ m?2 for daily irradiation). A comparison with monthly means from about 80 automatic weather

395

The Effect of Realistic Radiative Transfer on Potential Vorticity Structures, Including the Influence of Background Shear and Strain  

Science Conference Proceedings (OSTI)

A modified version of the radiation scheme of Shine is used to investigate the decay of small-scale potential vorticity structures characteristic of those observed in the lower and middle stratosphere. Following Fels, effective thermal damping ...

P. H. Haynes; W. E. Ward

1993-10-01T23:59:59.000Z

396

he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study  

SciTech Connect

This project examined the potential large-scale influence of marine aerosol cycling on atmospheric chemistry, physics and radiative transfer. Measurements indicate that the size-dependent generation of marine aerosols by wind waves at the ocean surface and the subsequent production and cycling of halogen-radicals are important but poorly constrained processes that influence climate regionally and globally. A reliable capacity to examine the role of marine aerosol in the global-scale atmospheric system requires that the important size-resolved chemical processes be treated explicitly. But the treatment of multiphase chemistry across the breadth of chemical scenarios encountered throughout the atmosphere is sensitive to the initial conditions and the precision of the solution method. This study examined this sensitivity, constrained it using high-resolution laboratory and field measurements, and deployed it in a coupled chemical-microphysical 3-D atmosphere model. First, laboratory measurements of fresh, unreacted marine aerosol were used to formulate a sea-state based marine aerosol source parameterization that captured the initial organic, inorganic, and physical conditions of the aerosol population. Second, a multiphase chemical mechanism, solved using the Max Planck Institute for Chemistry??s MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) system, was benchmarked across a broad set of observed chemical and physical conditions in the marine atmosphere. Using these results, the mechanism was systematically reduced to maximize computational speed. Finally, the mechanism was coupled to the 3-mode modal aerosol version of the NCAR Community Atmosphere Model (CAM v3.6.33). Decadal-scale simulations with CAM v.3.6.33, were run both with and without reactive-halogen chemistry and with and without explicit treatment of particulate organic carbon in the marine aerosol source function. Simulated results were interpreted (1) to evaluate influences of marine aerosol production on the microphysical properties of aerosol populations and clouds over the ocean and the corresponding direct and indirect effects on radiative transfer; (2) atmospheric burdens of reactive halogen species and their impacts on O3, NOx, OH, DMS, and particulate non-sea-salt SO42-; and (3) the global production and influences of marine-derived particulate organic carbon. The model reproduced major characteristics of the marine aerosol system and demonstrated the potential sensitivity of global, decadal-scale climate metrics to multiphase marine-derived components of Earth??s troposphere. Due to the combined computational burden of the coupled system, the currently available computational resources were the limiting factor preventing the adequate statistical analysis of the overall impact that multiphase chemistry might have on climate-scale radiative transfer and climate.

Keene, William C. [University of Virginia] [University of Virginia; Long, Michael S. [University of Virginia] [University of Virginia

2013-05-20T23:59:59.000Z

397

Modeling the Heating of Biological Tissue based on the Hyperbolic Heat Transfer Equation  

E-Print Network (OSTI)

In modern surgery, a multitude of minimally intrusive operational techniques are used which are based on the punctual heating of target zones of human tissue via laser or radio-frequency currents. Traditionally, these processes are modeled by the bioheat equation introduced by Pennes, who considers Fourier's theory of heat conduction. We present an alternative and more realistic model established by the hyperbolic equation of heat transfer. To demonstrate some features and advantages of our proposed method, we apply the obtained results to different types of tissue heating with high energy fluxes, in particular radiofrequency heating and pulsed laser treatment of the cornea to correct refractive errors. Hopefully, the results of our approach help to refine surgical interventions in this novel field of medical treatment.

Tung, M M; Molina, J A Lopez; Rivera, M J; Berjano, E J

2008-01-01T23:59:59.000Z

398

Transport, Radiative, and Dynamical Effects of the Antarctic Ozone Hole: A GFDL SKYHI Model Experiment  

Science Conference Proceedings (OSTI)

The GFDL SKYHI general circulation model has been used to simulate the effect of the Antarctic ozone hole phenomenon on the radiative and dynamical environment of the lower stratosphere. Both the polar ozone destruction and photochemical ...

J. D. Mahlman; L. J. Umscheid; J. P. Pinto

1994-02-01T23:59:59.000Z

399

A Comparison of Radiation Variables Calculated in the UCLA General Circulation Model to Observations  

Science Conference Proceedings (OSTI)

Comparisons are made between the spatial patterns of solar and thermal fluxes of radiation calculated by the UCLA general circulation model and observations. The latter include estimates at the Pacific Ocean surface of the climatological averages ...

Bryan C. Weare

1988-05-01T23:59:59.000Z

400

An Upper Boundary Condition Permitting Internal Gravity Wave Radiation in Numerical Mesoscale Models  

Science Conference Proceedings (OSTI)

A radiative upper boundary condition is proposed for numerical mesoscale models which allows vertically propagating internal gravity waves to pass out of the computational domain with minimal reflection. In this formulation, the pressure along ...

Joseph B. Klemp; Dale R. Durran

1983-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

The Response of a Spectral General Circulation Model to Refinements in Radiative Processes  

Science Conference Proceedings (OSTI)

We present here results and analyses of a series of numerical experiments performed with a spectral general circulation model (GCM). The purpose of the GCM experiments is to examine the role of radiation/cloud processes in the general circulation ...

V. Ramanathan; Eric J. Pitcher; Robert C. Malone; Maurice L. Blackmon

1983-03-01T23:59:59.000Z

402

In vitro models for investigating keratinocyte responses to ultraviolet B radiation.  

E-Print Network (OSTI)

??This thesis describes the use of 2- and 3-dimensional cell-based models for studying how skin cells respond to ultraviolet radiation. These methods were used to (more)

Fernandez, Tara L.

2013-01-01T23:59:59.000Z

403

Radiative Characteristics of the Canadian Climate Centre Second-Generation General Circulation Model  

Science Conference Proceedings (OSTI)

Several observational datasets were used to assess the quality of the radiative characteristics of the Canadian Climate Centre (CCC) second-generation GCM. The GCM data were obtained from the Atmospheric Model Intercomparison Project (AMIP) ...

Howard W. Barker; Zhanqing Li; Jean-Pierre Blanchet

1994-07-01T23:59:59.000Z

404

Estimation of Shortwave Direct Radiative Forcing of Biomass-Burning Aerosols Using New Angular Models  

Science Conference Proceedings (OSTI)

Using a new angular distribution model (ADM) for smoke aerosols, the instantaneous top-of-atmosphere (TOA) shortwave aerosol radiative forcing (SWARF) is calculated for selected days over biomass-burning regions in South America. The visible and ...

Xiang Li; Sundar A. Christopher; Joyce Chou; Ronald M. Welch

2000-12-01T23:59:59.000Z

405

Effects of Ocean Biology on the Penetrative Radiation in a Coupled Climate Model  

Science Conference Proceedings (OSTI)

The influence of phytoplankton on the seasonal cycle and the mean global climate is investigated in a fully coupled climate model. The control experiment uses a fixed attenuation depth for shortwave radiation, while the attenuation depth in the ...

Patrick Wetzel; Ernst Maier-Reimer; Michael Botzet; Johann Jungclaus; Noel Keenlyside; Mojib Latif

2006-08-01T23:59:59.000Z

406

Evaluating Mesoscale Model Predictions of Clouds and Radiation with SGP ARM Data over a Seasonal Timescale  

Science Conference Proceedings (OSTI)

This study evaluates the predictions of radiative and cloud-related processes of the fifth-generation Pennsylvania State UniversityNational Center for Atmospheric Research (PSUNCAR) Mesoscale Model (MM5). It is based on extensive comparison of ...

Franoise Guichard; David B. Parsons; Jimy Dudhia; James Bresch

2003-05-01T23:59:59.000Z

407

A Model of the Radiative Properties of the EL Chichon Stratospheric Aerosol Layer  

Science Conference Proceedings (OSTI)

An accurate multiple-scattering model has been employed to examine the effect of an aerosol layer at 25 mb, corresponding to the EL Chichon observations, on the reflection, transmission and absorption of radiation by the stratosphere as a ...

Michael D. King; Harshvardhan; Albert Arking

1984-07-01T23:59:59.000Z

408

Technical assessment of the prevention of micro-fouling on OTEC heat-transfer surfaces through the use of ultraviolet radiation  

DOE Green Energy (OSTI)

To reduce or eliminate biofouling by microorganisms it has been suggested that the seawater entering the heat exchanger be sterilized (or at least sanitized) by uv radiation at 253.7 nm. The feasibility of applying this technology to OTEC is examined. Trivial calculations based on the Lambert-Beer equation and reasonable assumptions about seawater quality and the intensity of irradiation obtainable from a uv lamp suggest seawater may be transparent enough to a collimated beam of uv light to deliver effective germicidal doses to nearly 150 cm under some conditions. However, the practical limit on the depth of effective radiation from commercial lamps is severely restricted by many factors including the natural divergence of light, absorption and scattering in the media, intensity of radiation from the light source and so forth. Even under very favorable conditions a common design allowing uv light to penetrate 30 cm of water would have to permit the water at that distance to be in contact with the light for 20 seconds or so to deliver the germicidal effect of high quality sanitization but not necessarily sterilization. Macro-fouling, which may be more severe than micro-fouling, will not be affected by uv radiation (presuming an absence of symbiotic relationships). Parasitic power required for uv sources may be prohibitive under unfavorable conditions (i.e., unexpectedly high absorptivities of seawater, or excessive turbidity) or the absence of an industrial effort to scale up present uv equipment appropriate to OTEC needs. This latter event is unlikely for it appears that present uv lamps can be adapted to OTEC needs without major technological advancement. Power and cost estimates for uv installation and operation vary widely depending on the number of lamps needed for the OTEC configuration and the intensity of uv radiation actually required to prevent biofouling of heat transfer systems in OTEC designs.

Garrigan, G. A.; Schmitt, R. P.; Ciccone, V. J.

1981-09-01T23:59:59.000Z

409

Modifying EPA Radiation Risk Models Based on BEIR VII  

E-Print Network (OSTI)

for internal lung dose in Mayak Workers and external lung dose in the Life Span Study Cohort of Japanese Atomic Bomb Survivors exposed between the ages of 15 and 60 Figure 12-1A Age-time patterns in radiation. Introduction In 1994, EPA published a report, referred to as the "Blue Book," which lays out EPA's current

410

Radiative Heating Rates for Saharan Dust  

Science Conference Proceedings (OSTI)

A combined longwave and shortwave radiative transfer model was used to determine effects of Saharan dust on the radiative fluxes and heating/cooling rates in the atmosphere. Cases are treated for cloud-free and overcast conditions over the ocean ...

Toby N. Carlson; Stanley G. Benjamin

1980-01-01T23:59:59.000Z

411

Numerical Forecasting of Radiation Fog. Part I: Numerical Model and Sensitivity Tests  

Science Conference Proceedings (OSTI)

To improve the forecast of dense radiative fogs, a method has been developed using a one-dimensional model of the nocturnal boundary layer forced by the mesoscale fields provided by a 3D limited-area operational model. The 1D model involves a ...

Thierry Bergot; Daniel Guedalia

1994-06-01T23:59:59.000Z

412

Modeling and Forecasting the Onset and Duration of Severe Radiation Fog under Frost Conditions  

Science Conference Proceedings (OSTI)

A case of a severe radiation fog during frost conditions is analyzed as a benchmark for the development of a very high-resolution NWP model. Results by the Weather Research and Forecasting model (WRF) and the High-Resolution Limited-Area Model (...

I. R. van der Velde; G. J. Steeneveld; B. G. J. Wichers Schreur; A. A. M. Holtslag

2010-11-01T23:59:59.000Z

413

Coupling Aerosol-Cloud-Radiative Processes in the WRF-Chem Model: Investigating the Radiative Impact of Elevated Point Sources  

Science Conference Proceedings (OSTI)

The local and regional influence of elevated point sources on summertime aerosol forcing and cloud-aerosol interactions in northeastern North America was investigated using the WRF-Chem community model. The direct effects of aerosols on incoming solar radiation were simulated using existing modules to relate aerosol sizes and chemical composition to aerosol optical properties. Indirect effects were simulated by adding a prognostic treatment of cloud droplet number and adding modules that activate aerosol particles to form cloud droplets, simulate aqueous phase chemistry, and tie a two-moment treatment of cloud water (cloud water mass and cloud droplet number) to an existing radiation scheme. Fully interactive feedbacks thus were created within the modified model, with aerosols affecting cloud droplet number and cloud radiative properties, and clouds altering aerosol size and composition via aqueous processes, wet scavenging, and gas-phase-related photolytic processes. Comparisons of a baseline simulation with observations show that the model captured the general temporal cycle of aerosol optical depths (AODs) and produced clouds of comparable thickness to observations at approximately the proper times and places. The model slightly overpredicted SO2 mixing ratios and PM2.5 mass, but reproduced the range of observed SO2 to sulfate aerosol ratios, suggesting that atmospheric oxidation processes leading to aerosol sulfate formation are captured in the model. The baseline simulation was compared to a sensitivity simulation in which all emissions at model levels above the surface layer were set to zero, thus removing stack emissions. Instantaneous, site-specific differences for aerosol and cloud related properties between the two simulations could be quite large, as removing above-surface emission sources influenced when and where clouds formed within the modeling domain. When summed spatially over the finest resolution model domain (the extent of which corresponds to the typical size of a single GCM grid cell) and temporally over a three day analysis period, total rainfall in the sensitivity simulation increased by 31% over that in the baseline simulation. Fewer optically thin clouds, arbitrarily defined as a cloud exhibiting an optical depth less than 1, formed in the sensitivity simulation. Domain-averaged AODs dropped from 0.46 in the baseline simulation to 0.38 in the sensitivity simulation. The overall net effect of additional aerosols attributable to primary particulates and aerosol precursors from point source emissions above the surface was a domain-averaged reduction of 5 W m-2 in mean daytime downwelling shortwave radiation.

Chapman, Elaine G.; Gustafson, William I.; Easter, Richard C.; Barnard, James C.; Ghan, Steven J.; Pekour, Mikhail S.; Fast, Jerome D.

2009-02-01T23:59:59.000Z

414

A combined heat transfer and quartz dissolution/deposition model for a hot dry rock geothermal reservoir  

DOE Green Energy (OSTI)

A kinetic model of silica transport has been coupled to a heat transfer model for a Hot Dry Rock (HDR) geothermal reservoir to examine the effect of silica rock-water interactions on fracture aperture and permeability. The model accounts for both the dissolution and deposition of silica. Zones of local dissolution and deposition were predicted, but their effect on aperture and permeability were fairly small for all cases studied. Initial rock temperature, reservoir size, and the ratio of rock surface area to fluid volume have the largest effect on the magnitude of silica mass transferred between the liquid and solid phases. 13 refs., 6 figs.

Robinson, B.A.; Pendergrass, J.

1989-01-01T23:59:59.000Z

415

Working Group Reports Calibration of Radiation Codes Used in Climate Models:  

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

Working Group Reports Calibration of Radiation Codes Used in Climate Models: Comparison of Clear-Sky Calculations with Observations from the Spectral Radiation Experiment and the Atmospheric Radiation Measurement Program R. G. Ellingson, S. Shen, and J. Warner University of Maryland College Park, Maryland Background The InterComparison of Radiation Codes in Climate Models (ICRCCM) showed large differences between model calculations of longwave fluxes and heating rates-even for clear-sky conditions (Luther et al. 1988). The discrepancies could not be resolved with either pyrgeometer measurements or line-by-line calculations because * Pyrgeometer errors are the magnitude of the discrepancies. * Uncertainties in the physics of line wings and in the proper treatment of the continuum make it impossible

416

Modeling and experimental measurements of residual stress using synchrotron radiation  

SciTech Connect

This work was an extension of recent LLNL-related efforts to determine the most effective method for determining residual stress in metal components by non-destructive techniques. These activities have included neutron diffraction, x-ray diffraction, and ultrasonics. In 1988, we recognized that the newly installed UC/LLNL beam line at the Stanford Synchrotron Radiation Laboratory (SSRL) could be applied to determining lattice strains in a fashion helpful to our overall research goals. Pioneering work using synchrotron radiation for stress measurements had been reported in Japan. Benefits of a synchrotron source to our studies include a highly intense and monochromatic beam, with variable energies (allowing significant sample penetration) and very low beam divergence. 10 refs., 3 figs., 2 tabs.

Shackelford, J.F.

1989-05-08T23:59:59.000Z

417

A Prospective Cohort Study on Radiation-induced Hypothyroidism: Development of an NTCP Model  

Science Conference Proceedings (OSTI)

Purpose: To establish a multivariate normal tissue complication probability (NTCP) model for radiation-induced hypothyroidism. Methods and Materials: The thyroid-stimulating hormone (TSH) level of 105 patients treated with (chemo-) radiation therapy for head-and-neck cancer was prospectively measured during a median follow-up of 2.5 years. Hypothyroidism was defined as elevated serum TSH with decreased or normal free thyroxin (T4). A multivariate logistic regression model with bootstrapping was used to determine the most important prognostic variables for radiation-induced hypothyroidism. Results: Thirty-five patients (33%) developed primary hypothyroidism within 2 years after radiation therapy. An NTCP model based on 2 variables, including the mean thyroid gland dose and the thyroid gland volume, was most predictive for radiation-induced hypothyroidism. NTCP values increased with higher mean thyroid gland dose (odds ratio [OR]: 1.064/Gy) and decreased with higher thyroid gland volume (OR: 0.826/cm{sup 3}). Model performance was good with an area under the curve (AUC) of 0.85. Conclusions: This is the first prospective study resulting in an NTCP model for radiation-induced hypothyroidism. The probability of hypothyroidism rises with increasing dose to the thyroid gland, whereas it reduces with increasing thyroid gland volume.

Boomsma, Marjolein J.; Bijl, Hendrik P.; Christianen, Miranda E.M.C.; Beetz, Ivo; Chouvalova, Olga; Steenbakkers, Roel J.H.M. [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Laan, Bernard F.A.M. van der [Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Wolffenbuttel, Bruce H.R. [Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Oosting, Sjoukje F. [Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Schilstra, Cornelis [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Langendijk, Johannes A., E-mail: j.a.langendijk@umcg.nl [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)

2012-11-01T23:59:59.000Z

418

Macroscopic Model of Geomagnetic-Radiation from Air Showers  

E-Print Network (OSTI)

We have developed a macroscopic description of coherent electro-magnetic radiation from air showers initiated by ultra-high energy cosmic rays in the presence of the geo-magnetic field. This description offers a simple and direct insight in the relation between the properties of the air shower and the time-structure of the radio pulse. As we show the structure of the pulse is a direct reflection of the important length scales in the shower.

Scholten, Olaf

2008-01-01T23:59:59.000Z

419

Macroscopic Model of Geomagnetic-Radiation from Air Showers  

E-Print Network (OSTI)

We have developed a macroscopic description of coherent electro-magnetic radiation from air showers initiated by ultra-high energy cosmic rays in the presence of the geo-magnetic field. This description offers a simple and direct insight in the relation between the properties of the air shower and the time-structure of the radio pulse. As we show the structure of the pulse is a direct reflection of the important length scales in the shower.

Olaf Scholten; Klaus Werner

2008-08-14T23:59:59.000Z

420

Climate ModelSimulated Diurnal Cycles in HIRS Clear-Sky Brightness Temperatures  

Science Conference Proceedings (OSTI)

Clear-sky brightness temperature measurements from the High-Resolution Infrared Radiation Sounder (HIRS) are simulated with two climate models via a radiative transfer code. The models are sampled along the HIRS orbit paths to derive diurnal ...

Ian A. MacKenzie; Simon F. B. Tett; Anders V. Lindfors

2012-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "radiation transfer models" 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

Cloud-Resolving Model Simulation and Mosaic Treatment of Subgrid Cloud-Radiation Interaction  

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

Cloud-Resolving Model Simulation and Mosaic Treatment Cloud-Resolving Model Simulation and Mosaic Treatment of Subgrid Cloud-Radiation Interaction X. Wu Department of Geological and Atmospheric Sciences Iowa State University Ames, Iowa X.-Z. Liang Illinois State Water Survey University of Illinois at Urbana-Champaign Champaign, Illinois Introduction Improving the representation of cloud-radiation interaction is a major challenge for the global climate simulation. The development of cloud-resolving models (CRMs) and the extensive Atmospheric Radiation Measurements (ARMs) provide a unique opportunity for shading some lights on this problem. Current general circulation models (GCMs) predict cloud cover fractions and hydrometeor concentra- tions only in individual model layers, where clouds are assumed to be horizontally homogeneous in a

422

Modeling the Global Solar Radiation on the Earths Surface Using Atmospheric Deterministic and Intelligent Data-Driven Techniques  

Science Conference Proceedings (OSTI)

Three methods for analyzing and modeling the global shortwave radiation reaching the earths surface are presented in this study. Solar radiation is a very important input for many aspects of climatology, hydrology, atmospheric sciences, and ...

M. Santamouris; G. Mihalakakou; B. Psiloglou; G. Eftaxias; D. N. Asimakopoulos

1999-10-01T23:59:59.000Z

423

System modelling to support accelerated fuel transfer rate at EBR-II  

Science Conference Proceedings (OSTI)

The Experimental Breeder Reactor-II (EBR-II) ia a 62.5 MW(th) liquid metal reactor operated by Argonne National Laboratory for The United States Department of Energy. The reactor is located near Idaho Falls, Idaho at the Argonne-West site (ANL-W). Full power operation was achieved in 1964,- the reactor operated continuously since that time until October 1994 in a variety of configurations depending on the programmatic mission. A three year program was initiated in October, 1993 to replace the 330 depleted uranium blanket subassemblies (S/As) with stainless steel reflectors. It was intended to operate the reactor during the three year blanket unloading program, followed by about a half year of driver fuel unloading. However, in the summer of 1994, Congress dictacted that EBR-II be shut down October 1, and complete defueling without operation. To assist in the planning for resources needed for this defueling campaign, a mathematical model of the fuel handling sequence was developed utilizing the appropriate reliability factors and inherent mm constraints of each stage of the process. The model allows predictions of transfer rates under different scenarios. Additionally, it has facilitated planning of maintenance activities, as well as optimization of resources regarding manpower and modification effort. The model and its application is described in this paper.

Imel, G.R.; Houshyar, A.; Planchon, H.P.; Cutforth, D.C.

1995-06-01T23:59:59.000Z

424

Modeling of the radiation belt megnetosphere in decisional timeframes  

DOE Patents (OSTI)

Systems and methods for calculating L* in the magnetosphere with essentially the same accuracy as with a physics based model at many times the speed by developing a surrogate trained to be a surrogate for the physics-based model. The trained model can then beneficially process input data falling within the training range of the surrogate model. The surrogate model can be a feedforward neural network and the physics-based model can be the TSK03 model. Operatively, the surrogate model can use parameters on which the physics-based model was based, and/or spatial data for the location where L* is to be calculated. Surrogate models should be provided for each of a plurality of pitch angles. Accordingly, a surrogate model having a closed drift shell can be used from the plurality of models. The feedforward neural network can have a plurality of input-layer units, there being at least one input-layer unit for each physics-based model parameter, a plurality of hidden layer units and at least one output unit for the value of L*.

Koller, Josef; Reeves, Geoffrey D; Friedel, Reiner H.W.

2013-04-23T23:59:59.000Z

425

3D CFD ELECTROCHEMICAL AND HEAT TRANSFER MODEL OF AN INTERNALLY MANIFOLDED SOLID OXIDE ELECTROLYSIS CELL  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated at the Idaho National Laboratory for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Single-cell and five-cell results will be presented. Flow distribution through both models is discussed. Flow enters from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down ''U'' shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, oxygen-electrode and steam-electrode current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

Grant L. Hawkes; James E. O'Brien; Greg Tao

2011-11-01T23:59:59.000Z

426

A diffusion-kinetic model for pulverized-coal combustion and heat-and-mass transfer in a gas stream  

SciTech Connect

A diffusion-kinetic model for pulverized-coal combustion and heat-and-mass transfer in a gas stream is proposed, and the results of numerical simulation of the burnout dynamics of Kansk-Achinsk coals in the pulverized state at different treatment conditions and different model parameters are presented. The mathematical model describes the dynamics of thermochemical conversion of solid organic fuels with allowance for complex physicochemical phenomena of heat-and-mass exchange between coal particles and the gaseous environment.

E.A. Boiko; S.V. Pachkovskii [Polytechnic Institute, Federal University of Siberia, Krasnoyarsk (Russian Federation)

2008-12-15T23:59:59.000Z

427

Radiative Reactions and Coherence Modeling in the High Altitude Electromagnetic Pulse  

E-Print Network (OSTI)

A high altitude nuclear electromagnetic pulse (EMP) with a peak field intensity of 5 x 10^4 V/m carries momentum that results in a retarding force on the average Compton electron (radiating coherently to produce the waveform) with magnitude near that of the geomagnetic force responsible for the coherent radiation. The retarding force results from a self field effect. The Compton electron interaction with the self generated magnetic field due to the other electrons accounts for the momentum density in the propagating wave; interaction with the self generated electric field accounts for the energy flux density in the propagating wave. Coherent addition of radiation is also quantitatively modeled.

Charles N. Vittitoe; Mario Rabinowitz

2003-06-03T23:59:59.000Z

428

A Neural Network Approach for a Fast and Accurate Computation of a Longwave Radiative Budget  

Science Conference Proceedings (OSTI)

The authors have investigated the possibility of elaborating a new generation of radiative transfer models for climate studies based on the neural network technique. The authors show that their neural networkbased model, NeuroFlux, can be used ...

F. Chevallier; F. Chruy; N. A. Scott; A. Chdin

1998-11-01T23:59:59.000Z

429

Radiative Properties of Boundary Layer Clouds: Droplet Effective Radius versus Number Concentration  

Science Conference Proceedings (OSTI)

The plane-parallel model for the parameterization of clouds in global climate models is examined in order to estimate the effects of the vertical profile of the microphysical parameters on radiative transfer calculations for extended boundary ...

Jean-Louis Brenguier; Hanna Pawlowska; Lothar Schller; Rene Preusker; Jrgen Fischer; Yves Fouquart

2000-03-01T23:59:59.000Z

430

Overlap of Solar and Infrared Spectra and the Shortwave Radiative Effect of Methane  

Science Conference Proceedings (OSTI)

This paper focuses on two shortcomings of radiative transfer codes commonly used in climate models. The first aspect concerns the partitioning of solar versus infrared spectral energy. In most climate models, the solar spectrum comprises ...

J. Li; C. L. Curry; Z. Sun; F. Zhang

2010-07-01T23:59:59.000Z

431

Validation of the RRTM Shortwave Radiation Model and Comparison...  

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

use at European Center for Medium-Range Weather Forecasts (ECMWF) in their weather forecast model (Morcrette et al. 2001). The absorption coefficients required for RRTM are...

432

Posters Single-Column Model for Atmospheric Radiation Measurement...  

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

Measurement Sites: Model Development and Sensitivity Test Q. Xu and M. Dong Cooperative Institute of Mesoscale Meteorological Studies University of Oklahoma Norman,...

433

A faster algorithm for smoothed particle hydrodynamics with radiative transfer in the flux-limited diffusion approximation  

E-Print Network (OSTI)

We describe a new, faster implicit algorithm for solving the radiation hydrodynamics equations in the flux-limited diffusion approximation for smoothed particle hydrodynamics. This improves on the method elucidated in Whitehouse & Bate by using a Gauss-Seidel iterative method rather than iterating over the exchange of energy between pairs of particles. The new algorithm is typically many thousands of times faster than the old one, which will enable more complex problems to be solved. The new algorithm is tested using the same tests performed by Turner & Stone for ZEUS-2D, and repeated by Whitehouse & Bate.

Stuart C. Whitehouse; Matthew R. Bate; Joe J. Monaghan

2005-09-28T23:59:59.000Z

434

Application of mechanistic models for flow distribution and heat transfer in finned tube bundles.  

E-Print Network (OSTI)

?? The focus of this thesis was heat transfer and pressure drop in staggered tube bundles with solid and serrated fins. The first part of (more)

Eikill, Astrid Oygarden

2013-01-01T23:59:59.000Z

435

Heat transfer modeling at an interface between a porous medium and a free region.  

E-Print Network (OSTI)

??This work deals with the study of heat transfer between a porous medium and a free medium, using multi scale approaches. First, we derive the (more)

D'hueppe, Alinor

2011-01-01T23:59:59.000Z

436

The Development of a Non-Equilibrium Dispersed Flow Film Boiling Heat Transfer Modeling Package.  

E-Print Network (OSTI)

??The dispersed flow film boiling (DFFB) heat transfer regime is important to several applications including cryogenics, rocket engines, steam generators, and in the safety analysis (more)

Meholic, Michael

2011-01-01T23:59:59.000Z

437

Brazil Latitude Tilted Solar Radiation Model (40km) from INPE...  

Open Energy Info (EERE)

by INPE - National Institute for Space Research) were used to produce the dataset and SHAPE files.
The assessment of reliability levels of the BRASIL-SR model were performed...

438

Brazil Global Horizontal Solar Radiation Model (40km) from INPE  

Open Energy Info (EERE)

by INPE - National Institute for Space Research) were used to produce the dataset and SHAPE files.
The assessment of reliability levels of the BRASIL-SR model were performed...

439

Computer simulation and topological modeling of radiation effects in zircon  

E-Print Network (OSTI)

The purpose of this study is to understand on atomic level the structural response of zircon (ZrSiO4) to irradiation using molecular dynamics (MD) computer simulations, and to develop topological models that can describe ...

Zhang, Yi, 1979-

2006-01-01T23:59:59.000Z

440

Low Dose Radiation Research Program: Mechanistic Modeling of...  

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

Texas A&M University College Station TX 77843 The primary objective of this project is to provide data for building a mathematical model of the role of repair in the...

Note: This page contains sample records for the topic "radiation transfer models" 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

Ab Initio-Based Rate Theory Modeling of Radiation Induced ...  

Science Conference Proceedings (OSTI)

In this study, we construct a rate theory model to simulate RIS in Ni-Cr alloys ... Evolution and Hardening of High- and Low-Cu Reactor Pressure Vessel Steels.

442

Low Dose Radiation Research Program: A Model for Interphase Chromosome...  

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

the 46 interphase chromosomes is modeled as a random polymer involving 30 nm zig-zag chromatin fiber confined within a sphere whose radius is dependent upon the chromosome length...

443

Low Dose Radiation Cancer Risks: Epidemiological and Toxicological Models  

Science Conference Proceedings (OSTI)

The basic purpose of this one year research grant was to extend the two stage clonal expansion model (TSCE) of carcinogenesis to exposures other than the usual single acute exposure. The two-stage clonal expansion model of carcinogenesis incorporates the biological process of carcinogenesis, which involves two mutations and the clonal proliferation of the intermediate cells, in a stochastic, mathematical way. The current TSCE model serves a general purpose of acute exposure models but requires numerical computation of both the survival and hazard functions. The primary objective of this research project was to develop the analytical expressions for the survival function and the hazard function of the occurrence of the first cancer cell for acute, continuous and multiple exposure cases within the framework of the piece-wise constant parameter two-stage clonal expansion model of carcinogenesis. For acute exposure and multiple exposures of acute series, it is either only allowed to have the first mutation rate vary with the dose, or to have all the parameters be dose dependent; for multiple exposures of continuous exposures, all the parameters are allowed to vary with the dose. With these analytical functions, it becomes easy to evaluate the risks of cancer and allows one to deal with the various exposure patterns in cancer risk assessment. A second objective was to apply the TSCE model with varing continuous exposures from the cancer studies of inhaled plutonium in beagle dogs. Using step functions to estimate the retention functions of the pulmonary exposure of plutonium the multiple exposure versions of the TSCE model was to be used to estimate the beagle dog lung cancer risks. The mathematical equations of the multiple exposure versions of the TSCE model were developed. A draft manuscript which is attached provides the results of this mathematical work. The application work using the beagle dog data from plutonium exposure has not been completed due to the fact that the research project did not continue beyond its first year.

David G. Hoel, PhD

2012-04-19T23:59:59.000Z

444

Handbook of heat transfer fundamentals  

SciTech Connect

This handbook is on the fundamentals of heat transfer. It provides coverage on conduction, convection, and radiation and on thermophysical properties of materials.

Rohsenow, W.M.; Hartnett, J.P.; Ganic, E.N.

1985-01-01T23:59:59.000Z

445

Partnering Today: Technology Transfer Highlights  

THE LLNL TECHNOLOGY COMPANY PRODUCTS Partnering Today: Technology Transfer Highlights 10 Ametek-Ortec: High-precision Radiation Detectors ORTEC, a unit of AMETEK, is ...

446

Handbook of Anatomical Models for Radiation Dosimetry (To be published in 2009 in "Series in Medical Physics and Biomedical Engineering")  

E-Print Network (OSTI)

Environmental Exposures Nina Petoussi-Henss and Kimiaki Saito Chapter 18 External Radiation Exposures in Nuclear Power Plants W. Dan Reece, Chan Hyeong Kim, and X. George Xu Chapter 19 Bioassay for Internal RadiationHandbook of Anatomical Models for Radiation Dosimetry (To be published in 2009 in "Series

Linhardt, Robert J.

447

Radiation MHD modeling of a proposed dynamic hohlraum  

SciTech Connect

In this paper we report 2D radiation magnetohydrodynamic simulations of a dynamic hohlraum target designed to be driven by the Z accelerator at Sandia National Laboratory, Albuquerque New Mexico. Z generates currents up 20 MA with a rise time of 100 ns and peak electrical power of 40 TW. In this design we attempt to reduce the effects of magneto-Rayleigh Taylor (RT) modes by using a distributed initial density profile. Earlier work showed that ``tailoring`` the initial density profile could reduce the sheath acceleration and the number of e-foldings that the RT instability grows during the implosion . As the sheath moves in radially, fresh material is swept up or ``snow plowed``, providing a back pressure that counters the J x B force. A special profile can be found in which the unstable outer surface of the sheath implodes at constant velocity, reducing the classical growth rate to zero, although residual Richtmeyer-Meshkov type instability (instability of the snow-plow shock front) may be present. In practice, it is hard to create tailored initial density profiles due to the difficulty of machining and otherwise manipulating very low density materials. It becomes easier to manufacture these complex targets as the current, energy and load mass increase with large drivers. Z is the first fast pulse power device with enough energy to consider loads of this type.

Hammer, J.H. [Lawrence Livermore National Lab., CA (United States); De Groot, J.S. [Lawrence Livermore National Lab., CA (United States)|California Univ., Davis, CA (United States); Tabak, M.; Toor, A.; Zimmerman, G.B. [Lawrence Livermore National Lab., CA (United States)

1997-07-01T23:59:59.000Z

448

Heat and moisture transfer through clothing  

E-Print Network (OSTI)

R. C. Eberhart (ed), Heat transfer in medicine and biology.Convective and radiative heat transfer coefficients for2008. Study of heat and moisture transfer within multi-layer

Voelker, Conrad; Hoffmann, Sabine; Kornadt, Oliver; Arens, Edward; Zhang, Hui; Huizenga, Charlie

2009-01-01T23:59:59.000Z

449

Modeling with finite element the convective heat transfer in civil building EPS insulated walls  

Science Conference Proceedings (OSTI)

In this paper we present the analysis of convective heat transfer in the walls of a house insulated with polystyrene. In the first part we make an evaluation of the insulation that is currently used in the houses. We start the simulation using a real ... Keywords: convective heat transfer, dew-point, finite element, polystyrene insulation

Madalina Xenia Calbureanu; Mihai Lungu; Dragos Tutunea; Raluca Malciu; Alexandru Dima

2010-10-01T23:59:59.000Z

450

Broadband Model Performance for an Updated National Solar Radiation Database in the United States of America: Preprint  

DOE Green Energy (OSTI)

Updated review of broadband model performance in a project being done to update the existing United States National Solar Radiation Database (NSRDB).

Myers, D. R.; Wilcox, S.; Marion, W.; George, R.; Anderberg, M.

2005-09-01T23:59:59.000Z

451

Volterra network modeling of the nonlinear finite-impulse reponse of the radiation belt flux  

Science Conference Proceedings (OSTI)

We show how a general class of spatio-temporal nonlinear impulse-response forecast networks (Volterra networks) can be constructed from a taxonomy of nonlinear autoregressive integrated moving average with exogenous inputs (NAR-MAX) input-output equations, and used to model the evolution of energetic particle f uxes in the Van Allen radiation belts. We present initial results for the nonlinear response of the radiation belts to conditions a month earlier. The essential features of spatio-temporal observations are recovered with the model echoing the results of state space models and linear f nite impulse-response models whereby the strongest coupling peak occurs in the preceding 1-2 days. It appears that such networks hold promise for the development of accurate and fully data-driven space weather modelling, monitoring and forecast tools.

Taylor, M.; Daglis, I. A.; Anastasiadis, A. [Institute for Space Applications and Remote Sensing(ISARS), National Observatory of Athens (NOA), Metaxa and Vasillis Pavlou Street, Penteli, Athens 15236 (Greece); Vassiliadis, D. [Department of Physics, Hodges Hall, PO Box 6315, West Virginia University, Morgantown, WV 26506-6315 (United States)

2011-01-04T23:59:59.000Z

452

Radiation fog forecasting using a 1-dimensional model  

E-Print Network (OSTI)

The importance of fog forecasting to the aviation community, to road transportation and to the public at large is irrefutable. The deadliest aviation accident in history was in fact partly a result of fog back on 27 March 1977. This has, along with numerous less dramatic examples, helped focus many meteorological efforts into trying to forecast this phenomenon as accurately as possible. Until recently, methods of fog forecasting have relied primarily on the forecaster's ability to recognize surface weather patterns known to be favorable for producing fog and once it has formed, to state that it will persist unless the pattern changes. Unfortunately, while such methods have shown some success, many times they have led weather forecasters astray with regards to the onset and dissipation of the phenomenon. Fortunately, now with computers becoming ever-increasingly powerful, numerical models have been utilized to attempt to more accurately deal with the fog forecasting problem. This study uses a 1 dimensional model called COBEL to simulate several past fog cases in the hopes of mimicking its actual occurrence and determining what weather parameters the fog is most sensitive to. The goal is to create a technique where the weather forecaster will be able to run several fog forecasts with the model each time with different initial conditions representing the uncertain weather conditions. In this way, the forecaster will be able to use his expertise to choose the most likely scenario. Results indicate that COBEL is able to simulate the fog cases quite well. Issues remain with the model's handling of the gravitational settling rate, the fact that it currently does not include any vegetation, and its coupling process with the soil model. Nevertheless, simulations and sensitivity tests indicate that soil temperature, soil moisture, low-level winds, initial relative humidity, dew deposition and surface emissivity are the weather parameters that affect fog the most. These parameters will be prime candidates for the 1 dimensional ensemble (ODEP) technique described above.

Peyraud, Lionel

2001-01-01T23:59:59.000Z

453

STOCHASTIC MODELS OF SPACE RADIATION DNA DAMAGE RESPONSES AND CANCER RISKS  

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

STOCHASTIC MODELS OF SPACE RADIATION DNA DAMAGE STOCHASTIC MODELS OF SPACE RADIATION DNA DAMAGE RESPONSES AND CANCER RISKS Francis A. Cucinotta 1 , Janice M. Pluth 2 , Artem Ponomarev 3 , Shaowen Hu 3 , Jennifer Anderson 4 , Jane Harper 4 , and Peter O'Neill 4 1 NASA Lyndon B. Johnson Space Center, Houston TX, USA; 2 Lawrence Berkeley National Laboratory, Berkeley CA, USA; 3 U.S.R.A., Division of Life Sciences, Houston TX, USA; 4 MRC Radiation and Genome Stability Unit, Harwell, Didcot, UK Abstract: On space missions astronauts are exposed to a steady flux of galactic cosmic rays (GCR) consisting of high-energy protons and heavy ions. In the next decades long- term missions of up to 200 days to the Earth's moon and 1100 days to Mars are planed by NASA where cumulative doses will not be low (>100 mSv) albeit dose-

454

Low Dose Radiation Research Program: Modeling the Physics of Damage Cluster  

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

Modeling the Physics of Damage Cluster Formation in a Cellular Environment Modeling the Physics of Damage Cluster Formation in a Cellular Environment Larry Toburen East Carolina University Why This Project Modern tools of radiobiology are leading to many new discoveries regarding how cells and tissues respond to radiation exposure. We can now irradiate single cells and observe responses in adjacent cells. We can also measure clusters of radiation damage produced in DNA. The primary tools available to describe the initial spatial pattern of damage formed by the absorption of ionizing radiation are based on (MC) Monte Carlo simulations of the structure of charged particle tracks. Although many MC codes exist and considerable progress is being made in the incorporation of detailed macromolecular target structures into these codes, much of the interaction

455

Transfer coefficients for the Gibbs surface in a two-phase mixture in the non-equilibrium square gradient model  

E-Print Network (OSTI)

In this paper we calculate the transfer coefficients for evaporation and condensation of mixtures. We use the continuous profiles of various thermodynamic quantities through the interface, obtained in our previous works using the square gradient model. Furthermore we introduce the Gibbs surface and obtain the excess entropy production for a surface. Following the traditional non-equilibrium thermodynamic approach we introduce the surface transfer coefficients which we are able to determine from the continuous solution. The knowledge of these coefficients is important for many industrial applications which involve transport through a surface, such as for instance distillation. In our approach the values of the local resistivities in the liquid and the vapor phases are chosen on the basis of experimental values. In the interfacial region there are small peaks in these resistivities. Three amplitudes control the magnitude of these peaks. Possible values of these amplitudes are found by matching the diagonal transfer coefficients to values predicted by kinetic theory. Using these amplitudes we find that the value of the cross resistivities is 1-2 orders of magnitude higher then the one from kinetic theory. The results of both kinetic theory and molecular dynamics simulations support the existence of small peaks in the local resistivities in the interfacial region. The square gradient approach gives an independent way to determine the transfer coefficients for surfaces. The results indicate that kinetic theory underestimates the interfacial transfer coefficients in real fluids.

K. S. Glavatskiy; D. Bedeaux

2009-07-11T23:59:59.000Z

456

Intermodal transfer of spent fuel  

Science Conference Proceedings (OSTI)

As a result of the international standardization of containerized cargo handling in ports around the world, maritime shipment handling is particularly uniform. Thus, handier exposure parameters will be relatively constant for ship-truck and ship-rail transfers at ports throughout the world. Inspectors' doses are expected to vary because of jurisdictional considerations. The results of this study should be applicable to truck-to-rail transfers. A study of the movement of spent fuel casks through ports, including the loading and unloading of containers from cargo vessels, afforded an opportunity to estimate the radiation doses to those individuals handling the spent fuels with doses to the public along subsequent transportation routes of the fuel. A number of states require redundant inspections and for escorts over long distances on highways; thus handlers, inspectors, escort personnel, and others who are not normally classified as radiation workers may sustain doses high enough to warrant concern about occupational safety. This paper addresses the question of radiation safety for these workers. Data were obtained during, observation of the offloading of reactor spent fuel (research reactor spent fuel, in this instance) which included estimates of exposure times and distances for handlers, inspectors and other workers during offloading and overnight storage. Exposure times and distance were also for other workers, including crane operators, scale operators, security personnel and truck drivers. RADTRAN calculational models and parameter values then facilitated estimation of the dose to workers during incident-free ship-to-truck transfer of spent fuel.

Neuhauser, K.S. (Sandia National Labs., Albuquerque, NM (United States)); Weiner, R.F. (Western Washington Univ., Bellingham, WA (United States))

1991-01-01T23:59:59.000Z

457

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

Flow, Transport, and Heat Transfer in Porous and Fracturedtransport, and heat transfer in porous and fracturedflow, chemical transport, and heat transfer in rock. These

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

458

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

transport, and heat transfer processes in porous media. 2.1.mass transport, and heat-transfer processes through porousinvolved. These heat-transfer processes are complicated by

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

459

INVENTORY OF SOLAR RADIATION/SOLAR ENERGY SYSTEMS ESTIMATORS, MODELS, SITE-SPECIFIC DATA, AND PUBLICATIONS  

E-Print Network (OSTI)

INVENTORY OF SOLAR RADIATION/SOLAR ENERGY SYSTEMS ESTIMATORS, MODELS, SITE-SPECIFIC DATA, and Buildings Systems Integration Center National Renewable Energy Laboratory 8 July 2009 SOLAR SYSTEM POTENTIAL/calculators/PVWATTS/version1/ http://rredc.nrel.gov/solar/calculators/PVWATTS/version2/ Estimates the electrical energy

460

The Parameterization of Radiation for Numerical Weather Prediction and Climate Models  

Science Conference Proceedings (OSTI)

This paper presents a review of the various methods used to compute both the fluxes and the rate of heating and/or cooling due to atmospheric radiation for use in numerical models of atmospheric circulation. The paper does not follow, step by ...

Graeme L. Stephens

1984-04-01T23:59:59.000Z

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461

The Impact of Spatial Resolution on Model-Derived Radiative Heating  

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

Impact of Spatial Resolution Impact of Spatial Resolution on Model-Derived Radiative Heating W. O'Hirok and C. Gautier Institute for Computational Earth System Science University of California Santa Barbara, California C. Gautier Department of Geography University of California Santa Barbara, California Introduction At the typical spatial resolution of climate and weather forecasting models, clouds are portrayed as uniform plane-parallel entities with three-dimensional (3D) radiative effects generally considered not important. However, as the resolution of these models increase, and with the development of "super parameterizations" (embedded cloud resolving models), there is a need to assess the spatial resolution where 3D effects should not be neglected (Khairoutdinov and Randall 2001). In this study, we perform

462

Specification of Eddy Transfer Coefficients in Coarse-Resolution Ocean Circulation Models  

Science Conference Proceedings (OSTI)

Parametric representations of oceanic geostrophic eddy transfer of heat and salt are studied ranging fromhorizontal diffusion to the more physically based approaches of Green and Stone (GS) and Gent and McWilliams(GM). The authors argue for a ...

Martin Visbeck; John Marshall; Tom Haine; Mike Spall

1997-03-01T23:59:59.000Z

463

Numerical modeling of pool spreading, heat transfer and evaporation in liquefied natural gas (LNG).  

E-Print Network (OSTI)

?? This master's thesis is a continuation of previous theses written at ComputIT AS. It treats heat transfer to LNG pools boiling on water through (more)

Myrmo, ystein

2011-01-01T23:59:59.000Z

464

Stochastic modeling of the cell killing effect for low- and high-LET radiation  

E-Print Network (OSTI)

Theoretical modeling of biological response to radiation describes qualitatively and quantitatively the results of radiobiological effects at the molecular, chromosomal, and cellular level. The repair-misrepair (RMR) model is the radiobiological model chosen for our study. It models deoxyribonucleic acid (DNA) damage formation and lesion repair through linear and quadratic processes. Double strand breaks (DSB) are a critical lesion in DNA. With increasing LET, the number of DSB per track traversing the cell nucleus increases. Using a compound Poisson process (CPP), we describe DNA damage formation. Three models were considered: a simple CPP using constant LET, a CPP using a chord length distribution, and a CPP using specific energy distribution. In the two first cases, and for low LET radiation the initial distribution of DSB was well approximated by a Poisson distribution, while for high LET radiation the initial distribution of DSB deviated slightly from a Poisson distribution. In the last case, DSB distribution was much broader than a pure Poisson distribution. Datasets from the literature for seven human cell lines, exhibiting various sensitivities to radiation were analyzed. We compared stochastic, CPP, and CPP using chord length distribution, with deterministic RMR models. For low LET radiation and at high dose rates the stochastic survival results agree well with the deterministic survival results. Also the stochastic model allows for non-linearity at low doses due to the accumulation of sub-lethal damage. At low dose rates deterministic results overestimate the surviving fraction compared to stochastic results. For high LET radiation stochastic and deterministic survival results agree. Stochastic survival results using specific energy distribution diverged from deterministic results by underestimating the surviving fraction at low and high LET radiation. The dose rate sparing curve, representing surviving fraction at a dose of 10Gy vs. do