Modelling of Radiative Transfer in Light Sources
Eindhoven, Technische Universiteit
. . . . . . . . . . . . . . . 30 2.5.3 Temperature distribution . . . . . . . . . . . . . . . . . . . . . . . . . 32 2-X radiative transition that is responsible for the sulfur lamp's bright sun-like spectrum #12;Contents 1
Radiative Transfer Models for Gamma-Ray Bursts
Vurm, Indrek
2015-01-01T23:59:59.000Z
We present global radiative transfer models for heated relativistic jets. The simulations include all relevant radiative processes, starting deep in the opaque zone and following the evolution of radiation to and beyond the photosphere of the jet. The transfer models are compared with three gamma-ray bursts GRB 990123, GRB 090902B, and GRB 130427A, which have well-measured and different spectra. The models provide good fits to the observed spectra in all three cases. The fits give estimates for the jet magnetization parameter $\\varepsilon_{\\rm B}$ and the Lorentz factor $\\Gamma$. In the small sample of three bursts, $\\varepsilon_{\\rm B}$ varies between 0.01 and 0.1, and $\\Gamma$ varies between 340 and 1200.
Howard Barker; Jason Cole
2012-05-17T23:59:59.000Z
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.
Dual-scale 3-D approach for modeling radiative heat transfer in fibrous insulations
Tafreshi, Hooman Vahedi
Dual-scale 3-D approach for modeling radiative heat transfer in fibrous insulations R. Arambakam 2013 Keywords: Radiative heat transfer Dual-scale modeling Insulation media Fibrous media a b s t r a c a fiber diameter for which radiation heat transfer through a fibrous media is min- imal, ranging between 3
Tafreshi, Hooman Vahedi
Modeling the role of microstructural parameters in radiative heat transfer through disordered high-tempera- tures. Traditional studies of radiative heat transfer in fibrous materials have been the performance of fibrous materials used as radiative heat transfer insulation media. Although effective
Numerical Passage from Radiative Heat Transfer to Nonlinear Diffusion Models \\Lambda
Schmeiser, Christian
Numerical Passage from Radiative Heat Transfer to Nonlinear Diffusion Models \\Lambda A. Klar y C. Schmeiser z Abstract Radiative heat transfer equations including heat conduction are considÂ ered situations are presented. Keywords. radiative heat transfer, asymptotic analysis, nonlinear diffusion limit
Radiative transfer model for contaminated slabs : experimental validations
Andrieu, François; Schmitt, Bernard; Douté, Sylvain; Brissaud, Olivier
2015-01-01T23:59:59.000Z
This article presents a set of spectro-goniometric measurements of different water ice samples and the comparison with an approximated radiative transfer model. The experiments were done using the spectro-radiogoniometer described in Brissaud et al. (2004). The radiative transfer model assumes an isotropization of the flux after the second interface and is fully described in Andrieu et al. (2015). Two kind of experiments were conducted. First, the specular spot was closely investigated, at high angular resolution, at the wavelength of $1.5\\,\\mbox{\\mu m}$, where ice behaves as a very absorbing media. Second, the bidirectional reflectance was sampled at various geometries, including low phase angles on 61 wavelengths ranging from $0.8\\,\\mbox{\\mu m}$ to $2.0\\,\\mbox{\\mu m}$. In order to validate the model, we made a qualitative test to demonstrate the relative isotropization of the flux. We also conducted quantitative assessments by using a bayesian inversion method in order to estimate the parameters (e.g. sampl...
Interpretation of AIRS Data in Thin Cirrus Atmospheres Based on a Fast Radiative Transfer Model
Liou, K. N.
Interpretation of AIRS Data in Thin Cirrus Atmospheres Based on a Fast Radiative Transfer Model of California, Los Angeles, Los Angeles, California B. H. KAHN Jet Propulsion Laboratory, California Institute radiative transfer model has been developed for application to cloudy satellite data assimilation
Goudon, Thierry
A Coupled Model for Radiative Transfer: Doppler Effects, Equilibrium and Non-Equilibrium Diffusion. The interaction terms take into account both scattering and absorption/emission phenomena, as well as Doppler-diffusion equations. Key words. Hydrodynamic limits. Diffusion approximation. Radiative transfer. Doppler correction
SKIRT: the design of a suite of input models for Monte Carlo radiative transfer simulations
Baes, Maarten
2015-01-01T23:59:59.000Z
The Monte Carlo method is the most popular technique to perform radiative transfer simulations in a general 3D geometry. The algorithms behind and acceleration techniques for Monte Carlo radiative transfer are discussed extensively in the literature, and many different Monte Carlo codes are publicly available. On the contrary, the design of a suite of components that can be used for the distribution of sources and sinks in radiative transfer codes has received very little attention. The availability of such models, with different degrees of complexity, has many benefits. For example, they can serve as toy models to test new physical ingredients, or as parameterised models for inverse radiative transfer fitting. For 3D Monte Carlo codes, this requires algorithms to efficiently generate random positions from 3D density distributions. We describe the design of a flexible suite of components for the Monte Carlo radiative transfer code SKIRT. The design is based on a combination of basic building blocks (which can...
Global oceanic rainfall estimation from AMSR-E data based on a radiative transfer model
Jin, Kyoung-Wook
2006-04-12T23:59:59.000Z
An improved physically-based rainfall algorithm was developed using AMSR-E data based on a radiative transfer model. In addition, error models were designed and embedded in the algorithm to assess retrieval errors ...
Gitelson, Anatoly
Optimizing spectral indices and chemometric analysis of leaf chemical properties using radiative for Sciences, 260 Panama Street, Stanford, CA 94305, USA d Center for Advanced Land Management Information squares regression We used synthetic reflectance spectra generated by a radiative transfer model, PROSPECT
Gitelson, Anatoly
Optimizing spectral indices and chemometric analysis of leaf chemical properties using radiative for Sciences, 260 Panama Street, Stanford, CA 94305, USA d Center for Advanced Land Management Information regression We used synthetic reflectance spectra generated by a radiative transfer model, PROSPECT-5
Effective-medium model of wire metamaterials in the problems of radiative heat transfer
Mirmoosa, M. S., E-mail: mohammad.mirmoosa@aalto.fi; Nefedov, I. S., E-mail: igor.nefedov@aalto.fi; Simovski, C. R., E-mail: konstantin.simovski@aalto.fi [Department of Radio Science and Engineering, School of Electrical Engineering, Aalto University, P. O. Box 13000, 00076 Aalto (Finland); Rüting, F., E-mail: felix.ruting@uam.es [Departamento de Física Teorica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autonoma de Madrid, E-28049 (Spain)
2014-06-21T23:59:59.000Z
In the present work, we check the applicability of the effective medium model (EMM) to the problems of radiative heat transfer (RHT) through so-called wire metamaterials (WMMs)—composites comprising parallel arrays of metal nanowires. It is explained why this problem is so important for the development of prospective thermophotovoltaic (TPV) systems. Previous studies of the applicability of EMM for WMMs were targeted by the imaging applications of WMMs. The analogous study referring to the transfer of radiative heat is a separate problem that deserves extended investigations. We show that WMMs with practically realizable design parameters transmit the radiative heat as effectively homogeneous media. Existing EMM is an adequate tool for qualitative prediction of the magnitude of transferred radiative heat and of its effective frequency band.
A convective-radiative heat transfer model for gas core reactors
Chen, G.; Anghaie, S. [Univ. of Florida, Gainesville, FL (United States)
1995-12-31T23:59:59.000Z
A convective-radiative heat transfer model is developed and used to predict the temperature distribution in gaseous fuel nuclear reactor cores. The axisymmetric, thin layer Navier-Stokes equations with diffusive radiation source term are the basis for this modeling approach. An algebraic turbulence model is used to calculate the eddy viscosity. The Rosseland diffusion approximation is used to model the radiative heat transfer. A hybrid implicit-explicit numerical scheme with Gauss-Seidel iterative process and a highly stretched grid system near wall is employed to solve the governing equations. Several cases with different internal heat generation rates are modeled and analyzed. Results of the temperature distribution, wall heat flux and the associated Nusselt number are presented. The influence of the internal heat generation rate and the wall temperature on the radiative and convective wall heat fluxes are discussed. At gas and wall temperatures close to 3,500 K and 1,600 K, respectively, the radiative and convective heat transfer rates have similar values.
CROSS VALIDATION OF SATELLITE RADIATION TRANSFER MODELS DURING SWERA PROJECT IN BRAZIL
Heinemann, Detlev
CROSS VALIDATION OF SATELLITE RADIATION TRANSFER MODELS DURING SWERA PROJECT IN BRAZIL Enio B-970, SP, Brazil. Phone + 55 12 39456741, Fax + 55 12 39456810, fernando@dge.inpe.br. Samuel L. Abreu, Hans, Federal University of Santa Catarina -UFSC, Florianópolis, 88040-900, (SC), Brazil. Richard Perez
General Relativistic Radiative Transfer
S. Knop; P. H. Hauschildt; E. Baron
2006-11-30T23:59:59.000Z
We present a general method to calculate radiative transfer including scattering in the continuum as well as in lines in spherically symmetric systems that are influenced by the effects of general relativity (GR). We utilize a comoving wavelength ansatz that allows to resolve spectral lines throughout the atmosphere. The used numerical solution is an operator splitting (OS) technique that uses a characteristic formal solution. The bending of photon paths and the wavelength shifts due to the effects of GR are fully taken into account, as is the treatment of image generation in a curved spacetime. We describe the algorithm we use and demonstrate the effects of GR on the radiative transport of a two level atom line in a neutron star like atmosphere for various combinations of continuous and line scattering coefficients. In addition, we present grey continuum models and discuss the effects of different scattering albedos on the emergent spectra and the determination of effective temperatures and radii of neutron star atmospheres.
Heng, Kevin; Mendonça, João M.; Lee, Jae-Min, E-mail: kevin.heng@csh.unibe.ch, E-mail: joao.mendonca@csh.unibe.ch, E-mail: lee@physik.uzh.ch [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland)
2014-11-01T23:59:59.000Z
We present a comprehensive analytical study of radiative transfer using the method of moments and include the effects of non-isotropic scattering in the coherent limit. Within this unified formalism, we derive the governing equations and solutions describing two-stream radiative transfer (which approximates the passage of radiation as a pair of outgoing and incoming fluxes), flux-limited diffusion (which describes radiative transfer in the deep interior), and solutions for the temperature-pressure profiles. Generally, the problem is mathematically underdetermined unless a set of closures (Eddington coefficients) is specified. We demonstrate that the hemispheric (or hemi-isotropic) closure naturally derives from the radiative transfer equation if energy conservation is obeyed, while the Eddington closure produces spurious enhancements of both reflected light and thermal emission. We concoct recipes for implementing two-stream radiative transfer in stand-alone numerical calculations and general circulation models. We use our two-stream solutions to construct toy models of the runaway greenhouse effect. We present a new solution for temperature-pressure profiles with a non-constant optical opacity and elucidate the effects of non-isotropic scattering in the optical and infrared. We derive generalized expressions for the spherical and Bond albedos and the photon deposition depth. We demonstrate that the value of the optical depth corresponding to the photosphere is not always 2/3 (Milne's solution) and depends on a combination of stellar irradiation, internal heat, and the properties of scattering in both the optical and infrared. Finally, we derive generalized expressions for the total, net, outgoing, and incoming fluxes in the convective regime.
Greendyke, Robert Brian
1988-01-01T23:59:59.000Z
will examine the radiance model and various step models in order to determine their appropriateness to the flight regime of the AOTV. The final area to be investigated will be the effect of nonequilibrium corrections on the radiative heat transfer models... of T and e T will be valid as long as there is a reasonable amount vNs of nitrogen molecules in the flow. Radiative Heat Transfer Models For this study, four radiative heat transfer models were examined. One of these models is an optically thin radiance...
Modified Method of Characteristics for Transient Radiative Transfer
Katika, Kamal M.; Pilon, Laurent
2006-01-01T23:59:59.000Z
dimensional transient radiation heat transfer modeling usingradiation transport and laser applications”, Advances in Heat Transfer,Radiation element method for transient hyperbolic radiative transfer in plane parallel inhomogenous media”, Numerical Heat
Three-dimensional Radiative Transfer Modeling of the Polarization of the Sun's Continuous Spectrum
J. Trujillo Bueno; N. Shchukina
2008-12-18T23:59:59.000Z
Here we formulate and solve the 3D radiative transfer problem of the polarization of the solar continuous radiation. Our approach takes into account not only the anisotropy of the continuum radiation, but also the symmetry-breaking effects caused by the horizontal atmospheric inhomogeneities produced by the solar surface convection. Interestingly, our radiative transfer modeling in a well-known 3D hydrodynamical model of the solar photosphere shows remarkable agreement with the empirical data, significantly better than that obtained via the use of 1D atmospheric models. Although this result confirms that the above-mentioned 3D model was indeed a suitable choice for our Hanle-effect estimation of the substantial amount of "hidden" magnetic energy that is stored in the quiet solar photosphere, we have found however some small discrepancies whose origin may be due to uncertainties in the empirical data and/or in the thermal and density structure of the 3D model. For this reason, we have paid some attention also to other (more familiar) observables, like the center-limb variation of the continuum intensity, which we have calculated taking into account the scattering contribution to the continuum source function. The overall agreement with the observed center-limb variation turns out to be impressive, but we find a hint that the model's temperature gradients in the continuum forming layers could be slightly too steep, perhaps because all current simulations of solar surface convection and magnetoconvection compute the radiative flux divergence ignoring the fact that the effective polarizability is not completely negligible, especially in the downward-moving intergranular lane plasma.
Three Dimensional Radiative Transfer
Tom Abel
2000-05-09T23:59:59.000Z
Radiative Transfer (RT) effects play a crucial role in the thermal history of the intergalactic medium. Here I discuss recent advances in the development of numerical methods that introduce RT to cosmological hydrodynamics. These methods can also readily be applied to time dependent problems on interstellar and galactic scales.
Wang, Chenxi
2013-07-25T23:59:59.000Z
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...
Greendyke, Robert Brian
1988-01-01T23:59:59.000Z
A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN GREENDYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1988 Major Subject: Aerospace Engineering A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN...
T. A. Carroll; M. Kopf; K. G. Strassmeier
2008-07-24T23:59:59.000Z
The major challenges for a fully polarized radiative transfer driven approach to Zeeman-Doppler imaging are still the enormous computational requirements. In every cycle of the iterative interplay between the forward process (spectral synthesis) and the inverse process (derivative based optimization) the Stokes profile synthesis requires several thousand evaluations of the polarized radiative transfer equation for a given stellar surface model. To cope with these computational demands and to allow for the incorporation of a full Stokes profile synthesis into Doppler- and Zeeman-Doppler imaging applications as well as into large scale solar Stokes profile inversions, we present a novel fast and accurate synthesis method for calculating local Stokes profiles. Our approach is based on artificial neural network models, which we use to approximate the complex non-linear mapping between the most important atmospheric parameters and the corresponding Stokes profiles. A number of specialized artificial neural networks, are used to model the functional relation between the model atmosphere, magnetic field strength, field inclination, and field azimuth, on one hand and the individual components (I,Q,U,V) of the Stokes profiles, on the other hand. We performed an extensive statistical evaluation and show that our new approach yields accurate local as well as disk-integrated Stokes profiles over a wide range of atmospheric conditions. The mean rms errors for the Stokes I and V profiles are well below 0.2% compared to the exact numerical solution. Errors for Stokes Q and U are in the range of 1%. Our approach does not only offer an accurate approximation to the LTE polarized radiative transfer it, moreover, accelerates the synthesis by a factor of more than 1000.
The dusty MOCASSIN: fully self-consistent 3D photoionisation and dust radiative transfer models
B. Ercolano; M. J. Barlow; P. J. Storey
2005-07-02T23:59:59.000Z
We present the first 3D Monte Carlo (MC) photoionisation code to include a fully self-consistent treatment of dust radiative transfer (RT) within a photoionised region. This is the latest development (Version 2.0) of the gas-only photoionisation code MOCASSIN (Ercolano et al., 2003a), and employs a stochastic approach to the transport of radiation, allowing both the primary and secondary components of the radiation field to be treated self-consistently, whilst accounting for the scattering of radiation by dust grains mixed with the gas, as well as the absorption and emission of radiation by both the gas and the dust components. A set of rigorous benchmark tests have been carried out for dust-only spherically symmetric geometries and 2D disk configurations. MOCASSIN's results are found to be in agreement with those obtained by well established dust-only RT codes that employ various approaches to the solution of the RT problem. A model of the dust and of the photoionised gas components of the planetary nebula (PN) NGC 3918 is also presented as a means of testing the correct functioning of the RT procedures in a case where both gas and dust opacities are present. The two components are coupled via the heating of dust grains by the absorption of both UV continuum photons and resonance line photons emitted by the gas. The MOCASSIN results show agreement with those of a 1D dust and gas model of this nebula published previously, showing the reliability of the new code, which can be applied to a variety of astrophysical environments.
A Realizability-Preserving Discontinuous Galerkin Method for the $M_1$ Model of Radiative Transfer
Frank, Martin [RWTH Aachen University; Olbrant, Edgar [RWTH Aachen University; Hauck, Cory D [ORNL
2012-01-01T23:59:59.000Z
The M{sub 1} model for radiative transfer coupled to a material energy equation in planar geometry is studied in this paper. For this model to be well-posed, its moment variables must fulfill certain realizability conditions. Our main focus is the design and implementation of an explicit Runge-Kutta discontinuous Galerkin method which, under a more restrictive CFL condition, guarantees the realizability of the moment variables and the positivity of the material temperature. An analytical proof for our realizability-preserving scheme, which also includes a slope-limiting technique, is provided and confirmed by various numerical examples. Among other things, we present accuracy tests showing convergence up to fourth-order, compare our results with an analytical solution in a Riemann problem, and consider a Marshak wave problem.
Constraints on Blazar Jet Conditions During Gamma-Ray Flaring from Radiative Transfer Modeling
Aller, Margo F; Aller, Hugh D; Hovatta, Talvikki
2013-01-01T23:59:59.000Z
As part of a program to investigate jet flow conditions during GeV gamma-ray flares detected by Fermi, we are using UMRAO multi-frequency, centimeter-band total flux density and linear polarization monitoring observations to constrain radiative transfer models incorporating propagating shocks orientated at an arbitrary angle to the flow direction. We describe the characteristics of the model, illustrate how the data are used to constrain the models, and present results for three program sources with diverse characteristics: PKS 0420-01, OJ 287, and 1156+295. The modeling of the observed spectral behavior yields information on the sense, strength and orientation of the shocks producing the radio-band flaring; on the energy distribution of the radiating particles; and on the observer's viewing angle with respect to the jet independent of VLBI data. We present evidence that, while a random component dominates the jet magnetic field, a distinguishing feature of those radio events with an associated gamma-ray flar...
Radiative-transfer models for supernovae IIb/Ib/Ic from binary-star progenitors
Dessart, Luc; Woosley, Stan; Livne, Eli; Waldman, Roni; Yoon, Sung-Chul; Langer, Norbert
2015-01-01T23:59:59.000Z
We present 1-D non-Local-Thermodynamic-Equilibrium time-dependent radiative-transfer simulations for supernovae (SNe) of type IIb, Ib, and Ic that result from the terminal explosion of the mass donor in a close-binary system. Here, we select three ejecta with a total kinetic energy of ~1.2e51erg, but characterised by different ejecta masses (2-5Msun), composition, and chemical mixing. The type IIb/Ib models correspond to the progenitors that have retained their He-rich shell at the time of explosion. The type Ic model arises from a progenitor that has lost its helium shell, but retains 0.32Msun of helium in a CO-rich core of 5.11Msun. We discuss their photometric and spectroscopic properties during the first 2-3 months after explosion, and connect these to their progenitor and ejecta properties including chemical stratification. For these three models, Arnett's rule overestimates the 56Ni mass by ~50% while the procedure of Katz et al., based on an energy argument, yields a more reliable estimate. The presenc...
RADIATIVE HEAT TRANSFER WITH QUASIMONTE CARLO METHODS \\Lambda
RADIATIVE HEAT TRANSFER WITH QUASIMONTE CARLO METHODS \\Lambda A. Kersch 1 W. Morokoff 2 A accuracy modeling of the radiative heat transfer from the heater to the wafer. Figure 1 shows the draft Carlo simulation is often used to solve radiative transfer problems where complex physical phenomena
RADIATIVE HEAT TRANSFER WITH QUASI-MONTE CARLO METHODS
RADIATIVE HEAT TRANSFER WITH QUASI-MONTE CARLO METHODS A. Kersch1 W. Moroko2 A. Schuster1 1Siemens of Quasi-Monte Carlo to this problem. 1.1 Radiative Heat Transfer Reactors In the manufacturing of the problems which can be solved by such a simulation is high accuracy modeling of the radiative heat transfer
Radiative heat transfer in inhomogeneous, nongray, and anisotropically scattering media
Guo, Zhixiong "James"
Radiative heat transfer in inhomogeneous, nongray, and anisotropically scattering media Zhixiong Radiative heat transfer in three-dimensional inhomogeneous, nongray and anisotropically scattering of an application of engineering interest, radiative heat transfer in a boiler model with non-isothermal, nongray
Order Reduction of the Radiative Heat Transfer Model for the Simulation of Plasma Arcs
Fagiano, Lorenzo
2015-01-01T23:59:59.000Z
An approach to derive low-complexity models describing thermal radiation for the sake of simulating the behavior of electric arcs in switchgear systems is presented. The idea is to approximate the (high dimensional) full-order equations, modeling the propagation of the radiated intensity in space, with a model of much lower dimension, whose parameters are identified by means of nonlinear system identification techniques. The low-order model preserves the main structural aspects of the full-order one, and its parameters can be straightforwardly used in arc simulation tools based on computational fluid dynamics. In particular, the model parameters can be used together with the common approaches to resolve radiation in magnetohydrodynamic simulations, including the discrete-ordinate method, the P-N methods and photohydrodynamics. The proposed order reduction approach is able to systematically compute the partitioning of the electromagnetic spectrum in frequency bands, and the related absorption coefficients, tha...
da Costa, Fatima Rubio; Petrosian, Vahe'; Carlsson, Mats
2015-01-01T23:59:59.000Z
Solar flares involve complex processes that are coupled together and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present such a model to simulate the coupling of high-energy particle kinetics with hydrodynamics of the atmospheric plasma. We combine the Stanford unified Fokker-Planck code that models particle acceleration, transport, and bremsstrahlung radiation with the RADYN hydrodynamic code that models the atmospheric response to collisional heating by non-thermal electrons through detailed radiative transfer calculations. We perform simulations using different injection electron spectra, including an {\\it ad hoc} power law and more realistic spectra predicted by the stochastic acceleration model due to turbulence or plasma waves. Surprisingly, stochastically accelerated electrons, even with energy flux $\\ll 10^{10}$ erg s$^{-1}$ cm$^{-2}$, cause "explosive" chromospheric evaporation and drive stronger up- an...
3D hydrodynamical and radiative transfer modeling of Eta Carinae's colliding winds
Madura, Thomas I; Gull, Theodore R; Kruip, Chael J H; Paardekooper, Jan-Pieter; Icke, Vincent
2015-01-01T23:59:59.000Z
We present results of full 3D hydrodynamical and radiative transfer simulations of the colliding stellar winds in the massive binary system Eta Carinae. We accomplish this by applying the SimpleX algorithm for 3D radiative transfer on an unstructured Voronoi-Delaunay grid to recent 3D smoothed particle hydrodynamics (SPH) simulations of the binary colliding winds. We use SimpleX to obtain detailed ionization fractions of hydrogen and helium, in 3D, at the resolution of the original SPH simulations. We investigate several computational domain sizes and Luminous Blue Variable primary star mass-loss rates. We furthermore present new methods of visualizing and interacting with output from complex 3D numerical simulations, including 3D interactive graphics and 3D printing. While we initially focus on Eta Car, the methods employed can be applied to numerous other colliding wind (WR 140, WR 137, WR 19) and dusty 'pinwheel' (WR 104, WR 98a) binary systems. Coupled with 3D hydrodynamical simulations, SimpleX simulatio...
Jones, Peter JS
the scope to include structurally complex 3-D plant architectures with and without background topography/need for RT models to accurately reproduce local estimates of radiative quantities under conditions) to a reassessment of the role, scope, and opportunities of the RAMI project in the future. Citation: Widlowski, J
Jones, Peter JS
. The second phase expanded the scope to include structurally com-9 plex 3-D plant architectures agreement since RAMI-2, and the capability of/need for RT models to15 accurately reproduce local estimates and opportunities of the RAMI project in the future.22 1. Introduction Space-borne observations constitute a highly
Radiative Heat Transfer in Enhanced Hydrogen Outgassing of Glass
Kitamura, Rei; Pilon, Laurent
2009-01-01T23:59:59.000Z
and J.R. Howell, Thermal radiation heat transfer, Hemispheremade: 1. The heat, mass, and radiation transfer are treatedOne- dimensional heat, mass, and radiation transfers were
Radiative transfer in molecular lines
A. Asensio Ramos; J. Trujillo Bueno; J. Cernicharo
2001-02-15T23:59:59.000Z
The highly convergent iterative methods developed by Trujillo Bueno and Fabiani Bendicho (1995) for radiative transfer (RT) applications are generalized to spherical symmetry with velocity fields. These RT methods are based on Jacobi, Gauss-Seidel (GS), and SOR iteration and they form the basis of a new NLTE multilevel transfer code for atomic and molecular lines. The benchmark tests carried out so far are presented and discussed. The main aim is to develop a number of powerful RT tools for the theoretical interpretation of molecular spectra.
Radiative transfer in decomposed domains
T. Heinemann; W. Dobler; A. Nordlund; A. Brandenburg
2005-11-09T23:59:59.000Z
An efficient algorithm for calculating radiative transfer on massively parallel computers using domain decomposition is presented. The integral formulation of the transfer equation is used to divide the problem into a local but compute-intensive part for calculating the intensity and optical depth integrals, and a nonlocal part for communicating the intensity between adjacent processors. The waiting time of idle processors during the nonlocal communication part does not have a severe impact on the scaling. The wall clock time thus scales nearly linearly with the inverse number of processors.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lee, W. -L.; Gu, Y.; Liou, K. N.; Leung, L. R.; Hsu, H. -H.
2014-12-15T23:59:59.000Z
We investigate 3-D mountain effects on solar flux distributions and their impact on surface hydrology over the Western United States, specifically the Rocky Mountains and Sierra Nevada using CCSM4 (CAM4/CLM4) global model with a 0.23° × 0.31° resolution for simulations over 6 years. In 3-D radiative transfer parameterization, we have updated surface topography data from a resolution of 1 km to 90 m to improve parameterization accuracy. In addition, we have also modified the upward-flux deviation [3-D - PP (plane-parallel)] adjustment to ensure that energy balance at the surface is conserved in global climate simulations based on 3-D radiation parameterization.more »We show that deviations of the net surface fluxes are not only affected by 3-D mountains, but also influenced by feedbacks of cloud and snow in association with the long-term simulations. Deviations in sensible heat and surface temperature generally follow the patterns of net surface solar flux. The monthly snow water equivalent (SWE) deviations show an increase in lower elevations due to reduced snowmelt, leading to a reduction in cumulative runoff. Over higher elevation areas, negative SWE deviations are found because of increased solar radiation available at the surface. Simulated precipitation increases for lower elevations, while decreases for higher elevations with a minimum in April. Liquid runoff significantly decreases in higher elevations after April due to reduced SWE and precipitation.« less
Klaus M. Pontoppidan; Cornelis P. Dullemond; Ewine F. van Dishoeck; Geoffrey A. Blake; Adwin C. A. Boogert; Neal J. Evans II; Jacqueline E. Kessler-Silacci; Fred Lahuis
2004-11-13T23:59:59.000Z
We present 5.2-37.2 micron spectroscopy of the edge-on circumstellar disk CRBR 2422.8-3423 obtained using the InfraRed Spectrograph (IRS) of the Spitzer Space Telescope. The IRS spectrum is combined with ground-based 3-5 micron spectroscopy to obtain a complete inventory of solid state material present along the line of sight toward the source. We model the object with a 2D axisymmetric (effectively 3D) Monte Carlo radiative transfer code. It is found that the model disk, assuming a standard flaring structure, is too warm to contain the very large observed column density of pure CO ice, but is possibly responsible for up to 50% of the water, CO2 and minor ice species. In particular the 6.85 micron band, tentatively due to NH4+, exhibits a prominent red wing, indicating a significant contribution from warm ice in the disk. It is argued that the pure CO ice is located in the dense core Oph-F in front of the source seen in the submillimeter imaging, with the CO gas in the core highly depleted. The model is used to predict which circumstances are most favourable for direct observations of ices in edge-on circumstellar disks. Ice bands will in general be deepest for inclinations similar to the disk opening angle, i.e. ~70 degrees. Due to the high optical depths of typical disk mid-planes, ice absorption bands will often probe warmer ice located in the upper layers of nearly edge-on disks. The ratios between different ice bands are found to vary by up to an order of magnitude depending on disk inclination due to radiative transfer effects caused by the 2D structure of the disk. Ratios between ice bands of the same species can therefore be used to constrain the location of the ices in a circumstellar disk. [Abstract abridged
Radiative Heat Transfer in Enhanced Hydrogen Outgassing of Glass
Kitamura, Rei; Pilon, Laurent
2009-01-01T23:59:59.000Z
Kaviany and B.P. Singh, “Radiative heat transfer in porousmedia”, Advances in Heat Transfer, vol. 23, no. 23, pp. 133–Thermal radiation heat transfer, Hemisphere Publishing Co. ,
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lee, W.-L.; Gu, Y.; Liou, K. N.; Leung, L. R.; Hsu, H.-H.
2015-01-01T23:59:59.000Z
We investigate 3-D mountain effects on solar flux distributions and their impact on surface hydrology over the western United States, specifically the Rocky Mountains and the Sierra Nevada, using the global CCSM4 (Community Climate System Model version 4; Community Atmosphere Model/Community Land Model – CAM4/CLM4) with a 0.23° × 0.31° resolution for simulations over 6 years. In a 3-D radiative transfer parameterization, we have updated surface topography data from a resolution of 1 km to 90 m to improve parameterization accuracy. In addition, we have also modified the upward-flux deviation (3-D–PP (plane-parallel)) adjustment to ensure that the energy balance atmore »the surface is conserved in global climate simulations based on 3-D radiation parameterization. We show that deviations in the net surface fluxes are not only affected by 3-D mountains but also influenced by feedbacks of cloud and snow in association with the long-term simulations. Deviations in sensible heat and surface temperature generally follow the patterns of net surface solar flux. The monthly snow water equivalent (SWE) deviations show an increase in lower elevations due to reduced snowmelt, leading to a reduction in cumulative runoff. Over higher-elevation areas, negative SWE deviations are found because of increased solar radiation available at the surface. Simulated precipitation increases for lower elevations, while it decreases for higher elevations, with a minimum in April. Liquid runoff significantly decreases at higher elevations after April due to reduced SWE and precipitation.« less
Calculating Radiative Heat Transfer in an Axisymmetric Closed Chamber: An Application
New York at Stoney Brook, State University of
the parallelization of the radiative heat transfer model introduced by Naraghi and Nunes of Manhattan College [8
Shumway, R.W.
1987-10-01T23:59:59.000Z
The ATHENA computer program has many features that make it desirable to use as a space reactor evaluation tool. One of the missing features was a surface-to-surface thermal radiation model. A model was developed that allows any of the regular ATHENA heat slabs to radiate to any other heat slab. The view factors and surface emissivities must be specified by the user. To verify that the model was properly accounting for radiant energy transfer, two different types of test calculations were performed. Both calculations have excellent results. The updates have been used on both the INEL CDC-176 and the Livermore Cray. 7 refs., 2 figs., 6 tabs.
Radiative heat transfer between dielectric bodies
Svend-Age Biehs
2011-03-16T23:59:59.000Z
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.
EXPERIMENTAL MEASUREMENT OF RADIATION HEAT TRANSFER FROM COMPLEX
EXPERIMENTAL MEASUREMENT OF RADIATION HEAT TRANSFER FROM COMPLEX FENESTRATION SYSTEMS By BARRY OF RADIATION HEAT TRANSFER FROM COMPLEX FENESTRATION SYSTEMS Thesis Approved: Dr. Dan Fisher Thesis Adviser Dr
Radiative transfer for the FIRST era
J. Trujillo Bueno
2001-02-15T23:59:59.000Z
This paper presents a brief overview of some recent advances in numerical radiative transfer, which may help the molecular astrophysics community to achieve new breakthroughs in the interpretation of spectro-(polarimetric) observations.
Radiative Heat Transfer between Neighboring Particles
Alejandro Manjavacas; F. Javier Garcia de Abajo
2012-01-26T23:59:59.000Z
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.
Application of three-dimensional solar radiative transfer to mountains Y. Chen,1,2
Liou, K. N.
Application of three-dimensional solar radiative transfer to mountains Y. Chen,1,2 A. Hall,1 and K November 2006. [1] We developed a three-dimensional radiative transfer model simulating solar fluxes over (2006), Application of three-dimensional solar radiative transfer to mountains, J. Geophys. Res., 111, D
Glass foams: formation, transport properties, and heat, mass, and radiation transfer
Pilon, Laurent
Glass foams: formation, transport properties, and heat, mass, and radiation transfer Andrei G models for thermophysical and transport properties and heat, mass, and radiation transfer in glass foams. In addition, the new results on simulation of combined conduction and radiation heat transfer in glass foams
Zhang, Zhibo
2009-05-15T23:59:59.000Z
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...
Zhang, Zhibo
2009-05-15T23:59:59.000Z
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...
Author's personal copy Radiative heat transfer in enhanced hydrogen
Pilon, Laurent
Author's personal copy Radiative heat transfer in enhanced hydrogen outgassing of glass Rei radiation. Combined conduction, radiation, and mass transfer were accounted for by solving the one-dimensional transient mass and energy conservation equations along with the steady-state radiative transfer equation
A Grey Radiative Transfer Procedure For Gamma-ray Transfer in Supernovae
David J. Jeffery
1998-11-23T23:59:59.000Z
The gamma-ray transfer in supernovae for the purposes of energy deposition in the ejecta can be approximated fairly accurately as frequency-integrated (grey) radiative transfer using a mean opacity as shown by Swartz, Sutherland, & Harkness (SSH). In SSH's grey radiative transfer procedure (unoptimized) the mean opacity is a pure absorption opacity and it is a constant aside from a usually weak composition dependence. In this paper, we present a variation on the SSH procedure which uses multiple mean opacities which have both absorption and scattering components. There is a mean opacity for each order of Compton scattering. A local-state (LS) approximation permits an analytic solution for the gamma-ray transfer of scattered gamma-ray fields. The LS approximation is admittedly crude, but the scattered fields are always of lesser importance to the energy deposition. We call our procedure the LS grey radiative transfer procedure or LS procedure for short. For a standard Type Ia supernova (SN Ia) model the uncertainty in gamma-ray energy deposition is estimated to be of order 10 % or less. The LS procedure code used for this paper can be obtained by request from the author. For completeness and easy reference, we include in this paper a review of the gamma-ray opacities important in supernovae, a discussion of the appropriate mean opacity prescription, and a discussion of the errors arising from neglecting time-dependent and non-static radiative transfer effects.
ULTRAFAST RADIATION HEAT TRANSFER IN LASER TISSUE WELDING AND SOLDERING
Guo, Zhixiong "James"
ULTRAFAST RADIATION HEAT TRANSFER IN LASER TISSUE WELDING AND SOLDERING Kyunghan Kim and Zhixiong. The transient radiation heat transfer in the picosecond time scale is numerically investigated for the first surface. Comparisons of radiation heat transfer are made between the spatially square- variance
Gardini, A; Pérez, E; Quesada, J A; Funke, B
2012-01-01T23:59:59.000Z
The Radiative Transfer Model (RTM) and the retrieval algorithm, incorporated in the SCIATRAN 2.2 software package developed at the Institute of Remote Sensing/Institute of Enviromental Physics of Bremen University (Germany), allows to simulate, among other things, radiance/irradiance spectra in the 2400-24 000 {\\AA} range. In this work we present applications of RTM to two case studies. In the first case the RTM was used to simulate direct solar irradiance spectra, with different water vapor amounts, for the study of the water vapor content in the atmosphere above Sierra Nevada Observatory. Simulated spectra were compared with those measured with a spectrometer operating in the 8000-10 000 {\\AA} range. In the second case the RTM was used to generate telluric model spectra to subtract the atmospheric contribution and correct high-resolution stellar spectra from atmospheric water vapor and oxygen lines. The results of both studies are discussed.
Development of a Heat Transfer Model for the Integrated Facade Heating
Gong, X.; Archer, D. H.; Claridge, D. E.
2007-01-01T23:59:59.000Z
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...
Development of a Heat Transfer Model for the Integrated Facade Heating
Gong, X.; Archer, D. H.; Claridge, D. E.
2007-01-01T23:59:59.000Z
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...
Parameterization and Analysis of 3-D Solar Radiative Transfer in Clouds: Final Report
Jerry Y. Harrington
2012-09-21T23:59:59.000Z
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.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Huang, Dong; Liu, Yangang
2014-09-27T23:59:59.000Z
The effects of subgrid cloud variability on grid-average microphysical rates and radiative fluxes are examined by use of long-term retrieval products at the Tropical West Pacific, Southern Great Plains, and North Slope of Alaska sites of the Department of Energy's Atmospheric Radiation Measurement program. Four commonly used distribution functions, the truncated Gaussian, Gamma, lognormal, and Weibull distributions, are constrained to have the same mean and standard deviation as observed cloud liquid water content. The probability density functions are then used to upscale relevant physical processes to obtain grid-average process rates. It is found that the truncated Gaussian representation results inmore »up to 30% mean bias in autoconversion rate, whereas the mean bias for the lognormal representation is about 10%. The Gamma and Weibull distribution function performs the best for the grid-average autoconversion rate with the mean relative bias less than 5%. For radiative fluxes, the lognormal and truncated Gaussian representations perform better than the Gamma and Weibull representations. The results show that the optimal choice of subgrid cloud distribution function depends on the nonlinearity of the process of interest, and thus, there is no single distribution function that works best for all parameterizations. Examination of the scale (window size) dependence of the mean bias indicates that the bias in grid-average process rates monotonically increases with increasing window sizes, suggesting the increasing importance of subgrid variability with increasing grid sizes.« less
Huang, Dong [Brookhaven National Lab. (BNL), Upton, NY (United States); Liu, Yangang [Brookhaven National Lab. (BNL), Upton, NY (United States)
2014-09-27T23:59:59.000Z
The effects of subgrid cloud variability on grid-average microphysical rates and radiative fluxes are examined by use of long-term retrieval products at the Tropical West Pacific, Southern Great Plains, and North Slope of Alaska sites of the Department of Energy's Atmospheric Radiation Measurement program. Four commonly used distribution functions, the truncated Gaussian, Gamma, lognormal, and Weibull distributions, are constrained to have the same mean and standard deviation as observed cloud liquid water content. The probability density functions are then used to upscale relevant physical processes to obtain grid-average process rates. It is found that the truncated Gaussian representation results in up to 30% mean bias in autoconversion rate, whereas the mean bias for the lognormal representation is about 10%. The Gamma and Weibull distribution function performs the best for the grid-average autoconversion rate with the mean relative bias less than 5%. For radiative fluxes, the lognormal and truncated Gaussian representations perform better than the Gamma and Weibull representations. The results show that the optimal choice of subgrid cloud distribution function depends on the nonlinearity of the process of interest, and thus, there is no single distribution function that works best for all parameterizations. Examination of the scale (window size) dependence of the mean bias indicates that the bias in grid-average process rates monotonically increases with increasing window sizes, suggesting the increasing importance of subgrid variability with increasing grid sizes.
Investigation of spectral radiation heat transfer and NO{sub x} emission in a glass furnace
Golchert, B.; Zhou, C. Q.; Chang, S. L.; Petrick, M.
2000-08-02T23:59:59.000Z
A comprehensive radiation heat transfer model and a reduced NOx kinetics model were coupled with a computational fluid dynamics (CFD) code and then used to investigate the radiation heat transfer, pollutant formation and flow characteristics in a glass furnace. The radiation model solves the spectral radiative transport equation in the combustion space of emitting and absorbing media, i.e., CO{sub 2}, H{sub 2}O, and soot and emission/reflection from the furnace crown. The advanced numerical scheme for calculating the radiation heat transfer is extremely effective in conserving energy between radiation emission and absorption. A parametric study was conducted to investigate the impact of operating conditions on the furnace performance with emphasis on the investigation into the formation of NOx.
Efficient wireless non-radiative mid-range energy transfer
Efficient wireless non-radiative mid-range energy transfer Aristeidis Karalis a,*, J-range wireless energy transfer. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Wireless energy; Wireless % few*LDEV) wireless energy transfer would be quite useful for many applica- tions. There are several
Radiative transfer with scattering from closely-spaced spheres
Drolen, B.L.
1986-01-01T23:59:59.000Z
Many heat-transfer applications including fluidized and packed beds, microsphere insulations, and reactor fuel pellets require the analysis of radiative transfer in packed-sphere systems. The radiative properties of surface deposits such as paint and soot layers, and of aerosols such as soot, may be determined by treating them as a collection of spheres. These properties are important for predicting heat transfer in furnaces and flames and for assessing atmospheric attenuation in nuclear-winter scenarios. For many applications when the particle size is larger than the wavelength, or when the volume fraction is small, scattering from individual spheres in the medium is independent of the influence of neighboring particles. Therefore the extinction characteristics of these systems are based on the properties of the discrete particles. This approach is shown to be in good agreement with published experimental data for a packed bed of spheres. When dependent scattering is important, effects caused by the proximity of the neighboring particles must be included. This model examines interference between the scattered waves from each of the particles in the medium. The particle centers correlate via a distribution function which represents the distribution of neighboring particles about a central particle.
The effect of the number of wavebands used in spectral radiation heat transfer calculations
Chang, S. L.; Golchert, B.; Petrick, M.
2000-05-09T23:59:59.000Z
A spectral radiation heat transfer model that conserves emitted and absorbed energy has been developed and used to model the combustion space of an industrial glass furnace. This comprehensive radiation heat transfer model coupled with a computational fluid dynamics (CFD) code was used to investigate the effect of spectral dependencies on the computed results. The results of this work clearly indicate the need for a spectral approach as opposed to a gray body approach since the gray body approach (one waveband) severely underestimates the energy emitted via radiation.
Application of Improved Radiation Modeling to General Circulation Models
Michael J Iacono
2011-04-07T23:59:59.000Z
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.
Stramski, Dariusz
Characterization of the solar light field within the ocean mesopelagic zone based on radiative light field Apparent optical properties Mesopelagic zone Radiative transfer modeling a b s t r a c t The solar light field within the ocean from the sea surface to the bottom of the mesopelagic zone
Small distance expansion for radiative heat transfer between curved objects
Golyk, Vladyslav A.
We develop a small distance expansion for the radiative heat transfer between gently curved objects, in terms of the ratio of distance to radius of curvature. A gradient expansion allows us to go beyond the lowest-order ...
Three-dimensional Radiative Transfer with Multilevel Atoms
P. Fabiani Bendicho; J. Trujillo Bueno
2007-10-29T23:59:59.000Z
The efficient numerical solution of Non-LTE multilevel transfer problems requires the combination of highly convergent iterative schemes with fast and accurate formal solution methods of the radiative transfer (RT) equation. This contribution begins presenting a method for the formal solution of the RT equation in three-dimensional (3D) media with horizontal periodic boundary conditions. This formal solver is suitable for both, unpolarized and polarized 3D radiative transfer and it can be easily combined with the iterative schemes for solving non-LTE multilevel transfer problems that we have developed over the last few years. We demonstrate this by showing some schematic 3D multilevel calculations that illustrate the physical effects of horizontal radiative transfer. These Non-LTE calculations have been carried out with our code MUGA 3D, a 3D multilevel Non-LTE code based on the Gauss-Seidel iterative scheme that Trujillo Bueno and Fabiani Bendicho (1995) developed for RT applications.
Enhanced radiative heat transfer between nanostructured gold plates
R. Guérout; 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
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.
Near field radiative heat transfer between two nonlocal dielectrics
Singer, F; Joulain, Karl
2015-01-01T23:59:59.000Z
We explore in the present work the near-field radiative heat transfer between two semi-infinite parallel nonlocal dielectric planes by means of fluctuational electrodynamics. We use atheory for the nonlocal dielectric permittivityfunction proposed byHalevi and Fuchs. This theory has the advantage to includedifferent models performed in the literature. According to this theory, the nonlocal dielectric function is described by a Lorenz-Drude like single oscillator model, in which the spatial dispersion effects are represented by an additional term depending on the square of the total wavevector k. The theory takes into account the scattering of the electromagneticexcitation at the surface of the dielectric material, which leads to the need of additional boundary conditions in order to solve Maxwell's equations and treat the electromagnetic transmission problem. The additional boundary conditions appear as additional surface scattering parameters in the expressions of the surface impedances. It is shown that the...
Atmospheric radiative transfer parametrization for solar energy yield calculations on buildings
Wagner, Jochen E
2015-01-01T23:59:59.000Z
In this paper the practical approach to evaluate the incoming solar radiation on buildings based on atmospheric composition and cloud cover is presented. The effects of absorption and scattering due to atmospheric composition is taken into account to calculate, using radiative transfer models, the net incoming solar radiation at surface level. A specific validation of the Alpine Region in Europe is presented with a special focus on the region of South Tyrol.
Modeling regional power transfers
Kavicky, J.A.; Veselka, T.D.
1994-03-01T23:59:59.000Z
The Spot Market Network (SMN) model was used to estimate spot market transactions and prices between various North American Electric Reliability Council (NERC) regions for summer on-peak situations. A preliminary analysis of new or proposed additions to the transmission network was performed. The effects of alternative exempt wholesale generator (EWG) options on spot market transactions and the transmission system are also studied. This paper presents the SMN regional modelling approach and summarizes simulation results. Although the paper focuses on a regional network representation, a discussion of how the SMN model was used to represent a detailed utility-level network is also presented.
Adaptive Ray Tracing for Radiative Transfer around Point Sources
Tom Abel; Benjamin D. Wandelt
2001-11-01T23:59:59.000Z
We describe a novel adaptive ray tracing scheme to solve the equation of radiative transfer around point sources in hydrodynamical simulations. The angular resolution adapts to the local hydrodynamical resolution and hence is of use for adaptive meshes as well as adaptive smooth particle hydrodynamical simulations. Recursive creation of rays ensures ease of implementation. The multiple radial integrations needed to solve the time dependent radiative transfer are sped up significantly using a quad-tree once the rays are cast. Simplifications advantageous for methods with one radiation source are briefly discussed. The suggested method is easily generalized to speed up Monte Carlo radiative transfer techniques. In summary a nearly optimal use of long characteristics is presented and aspects of its implementation and comparison to other methods are given.
Efficient weakly-radiative wireless energy transfer: An EIT-like approach
Efficient weakly-radiative wireless energy transfer: An EIT-like approach Rafif E. Hamam 2009 Keywords: Wireless energy transfer Coupling Electromagnetically induced transparency (EIT induced trans- parency (EIT), we propose an efficient weakly radiative wireless energy transfer scheme
Numerical methods for multidimensional radiative transfer
radiation plays a key role in various scientific applications, such as combustion physics, thermonuclear fusion and astrophysics. The equa- tion describing the transport of photons or neutrons through a medium
Nonlocal study of the near field radiative heat transfer between two n-doped semiconductors
Singer, F; Joulain, Karl
2015-01-01T23:59:59.000Z
We study in this work the near-field radiative heat transfer between two semi-infinite parallel planes of highly n-doped semiconductors. Using a nonlocal model of the dielectric permittivity, usually used for the case of metallic planes, we show that the radiative heat transfer coefficientsaturates as the separation distance is reduced for high doping concentration. These results replace the 1/d${}^2$ infinite divergence obtained in the local model case. Different features of the obtained results are shown to relate physically to the parameters of the materials, mainly the doping concentration and the plasmon frequency.
Demonstration of Strong Near-Field Radiative Heat Transfer between Integrated Nanostructures
Lipson, Michal
Demonstration of Strong Near-Field Radiative Heat Transfer between Integrated Nanostructures-polariton Recently, there has been a growing interest in controlling radiative heat transfer in the near-field,1 ultrahigh contrast rectification of heat transfer.27 Here we show strong near-field radiative heat transfer
Guo, Zhixiong "James"
Global heat transfer analysis in Czochralski silicon furnace with radiation on curved specular method are adopted to solve the global heat transfer and the radiative heat exchange, respectively rate QJ diffuse radiation heat transfer rate QX net rate of radiative heat loss QT heat generation rate
Test plan for validation of the radiative transfer equation.
Ricks, Allen Joseph; Grasser, Thomas W.; Kearney, Sean Patrick; Jernigan, Dann A.; Blanchat, Thomas K.
2010-09-01T23:59:59.000Z
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).
Aller, M F; Aller, H D; Jorstad, S G; Marscher, A P; Bala, V; Hovatta, T
2015-01-01T23:59:59.000Z
As part of a program to identify the physical conditions in the jets of gamma-ray-flaring blazars detected by Fermi, including the role of shocks in the production of high-energy flaring, we obtained 4 years of 3-frequency, centimeter-band total flux density and linear polarization monitoring observations of the radio-bright blazar S5 0716+714 with the University of Michigan 26-m paraboloid. Light curves constructed from these data exhibit a series of rapid, high-amplitude, centimeter-band total flux density outbursts, and changes in the linear polarization consistent with the passage of shocks during the gamma-ray flaring. The observed spectral evolution of the radio-band flares, in combination with radiative transfer simulations incorporating propagating shocks, was used to constrain the shock and jet flow conditions in the parsec-scale regions of the jet. Eight forward-moving, transverse shocks with unusually-strong shock compression factors, a very fast Lorentz factor of the shocks of 77, a bulk Lorentz f...
Dana E. Veron
2012-04-09T23:59:59.000Z
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.
Solving radiative transfer with line overlaps using Gauss Seidel algorithms
F. Daniel; J. Cernicharo
2008-07-11T23:59:59.000Z
The improvement in observational facilities requires refining the modelling of the geometrical structures of astrophysical objects. Nevertheless, for complex problems such as line overlap in molecules showing hyperfine structure, a detailed analysis still requires a large amount of computing time and thus, misinterpretation cannot be dismissed due to an undersampling of the whole space of parameters. We extend the discussion of the implementation of the Gauss--Seidel algorithm in spherical geometry and include the case of hyperfine line overlap. We first review the basics of the short characteristics method that is used to solve the radiative transfer equations. Details are given on the determination of the Lambda operator in spherical geometry. The Gauss--Seidel algorithm is then described and, by analogy to the plan--parallel case, we see how to introduce it in spherical geometry. Doing so requires some approximations in order to keep the algorithm competitive. Finally, line overlap effects are included. The convergence speed of the algorithm is compared to the usual Jacobi iterative schemes. The gain in the number of iterations is typically factors of 2 and 4 for the two implementations made of the Gauss--Seidel algorithm. This is obtained despite the introduction of approximations in the algorithm. A comparison of results obtained with and without line overlaps for N2H+, HCN, and HNC shows that the J=3-2 line intensities are significantly underestimated in models where line overlap is neglected.
Yuen, W W
2006-01-01T23:59:59.000Z
the effect of radiation heat transfer in multi-dimensionaleffects of the radiation heat transfer, particularly in3-D Surface Radiation Calculation”, Numerical heat Transfer,
Radiative heat transfer in 2D Dirac materials
Pablo Rodriguez-Lopez; Wang-Kong Tse; Diego A. R. Dalvit
2015-02-02T23:59:59.000Z
We compute the radiative heat transfer between two sheets of 2D Dirac materials, including topological Chern insulators and graphene, within the framework of the local approximation for the optical response of these materials. In this approximation, which neglects spatial dispersion, we derive both numerically and analytically the short-distance asymptotic of the near-field heat transfer in these systems, and show that it scales as the inverse of the distance between the two sheets. Finally, we discuss the limitations to the validity of this scaling law imposed by spatial dispersion in 2D Dirac materials.
He, Xing; Lee, Euntaek; Wilcox, Lucas; Munipalli, Ramakanth; Pilon, Laurent
2013-01-01T23:59:59.000Z
and M. P. Meng¨ u¸c, “Radiation heat transfer in combustionThermal radiation is a dominant mode of heat transfer inand radiation in the Atlas plume”, AIAA J. Thermophys. Heat Transfer,
Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped Emmanuel Rousseau
Paris-Sud XI, Université de
Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped silicon the role of surface plasmons for nanoscale radiative heat transfer between doped silicon surfaces. We derive a new accurate and closed-form expression of the radiative near- field heat transfer. We also
TWO-DIMENSIONAL TRANSIENT RADIATIVE HEAT TRANSFER USING DISCRETE ORDINATES METHOD
Guo, Zhixiong "James"
TWO-DIMENSIONAL TRANSIENT RADIATIVE HEAT TRANSFER USING DISCRETE ORDINATES METHOD Zhixiong Guo for the first time to solve transient radiative heat transfer in a two-dimensional rectangular enclosure of solution method of radiative heat transfer in participating media in recent decades. However, the analysis
Near-Field Radiative Heat Transfer between Macroscopic Planar Surfaces R. S. Ottens,1
Tanner, David B.
Near-Field Radiative Heat Transfer between Macroscopic Planar Surfaces R. S. Ottens,1 V. Quetschke-field, blackbody radiation. Although heat transfer via near-field effects has been discussed for many years.014301 PACS numbers: 44.40.+a, 78.20.Ci Humans knew of radiative heat transfer at least as early
An Investigation of the Radiative Heat Transfer through Nonwoven Fibrous Materials
Tafreshi, Hooman Vahedi
An Investigation of the Radiative Heat Transfer through Nonwoven Fibrous Materials Imad Qashou1 of the Fluent CFD code is used to investigate the response of a fibrous material to the radiative heat transfer in agreement with our experimental study. INTRODUCTION Radiative heat transfer through fibrous media has been
Radiative heat transfer in a hydrous mantle transition zone Sylvia-Monique Thomas a,n
Jacobsen, Steven D.
Radiative heat transfer in a hydrous mantle transition zone Sylvia-Monique Thomas a,n , Craig R contribute significantly to heat transfer in the mantle and demonstrate the importance of radiative heat, radiative heat transfer was considered relatively unimportant in the mantle. Earlier experimental work
Radiative Heat Transfer Analysis of Fibrous Insulation Materials Using the ZonalGEF Method
Yuen, Walter W.
Radiative Heat Transfer Analysis of Fibrous Insulation Materials Using the ZonalGEF Method Walter to analyze radiative heat transfer in high porosity insulation materials which have a large scattering. Radiative heat transfer in this class of material is nonlocalized in the optically thick limit
Heat transfer through a water spray curtain under the effect of a strong radiative source
Paris-Sud XI, Université de
Heat transfer through a water spray curtain under the effect of a strong radiative source P. Boulet - mail Pascal.Boulet@lemta.uhp-nancy.fr Keywords : heat transfer, radiative transfer, vaporization, convection, water spray Abstract Heat transfer inside a participating medium, made of droplets flowing in gas
He, Xing; Lee, Euntaek; Wilcox, Lucas; Munipalli, Ramakanth; Pilon, Laurent
2013-01-01T23:59:59.000Z
of radiative transfer in combustion systems”, Int. J. Numer.c, “Radiation heat transfer in combustion systems”, Progressin Energy and Combustion Science, vol. 13, no. 2, pp. 97–
WHICH MODEL OF TECHNOLOGY TRANSFER FOR NANOTECHNOLOGY?
Paris-Sud XI, Université de
1 WHICH MODEL OF TECHNOLOGY TRANSFER FOR NANOTECHNOLOGY? A Comparison with Biotech.genet@grenoble-em.com Website: www.nanoeconomics.eu Abstract. Nanotechnologies are often presented as breakthrough innovations. This article investigates the model of knowledge transfer in the nanotechnologies in depth, by comparing
Radiative transfer in the earth's atmosphere-ocean system using Monte Carlo techniques
Bradley, Paul Andrew
1987-01-01T23:59:59.000Z
TRANSFER PROBLEM MONTE CARLO METHOD Assumptions of the Model Photon Pathlength Emulation Techniques Sampling Scattering Functions: Angles and Probabilities Emulation of an Interface Computing the Radiance by Statistical Estimation Determination... radiance values in both the atmosphere and the ocean from the scattering functions and other input data, with a Monte Carlo computer code. The polarization ot the radiation was taken into account by Kattawar et al. s in their computation...
Impact of surface inhomogeneity on solar radiative transfer under overcast conditions
Li, Zhanqing
Impact of surface inhomogeneity on solar radiative transfer under overcast conditions Zhanqing Li1. Introduction [2] Solar radiative heating is the primary driving force of atmospheric and oceanic movements underlines the impact of surface inhomogeneity on the closure of SW radiative transfer. It also leads
Liou, K. N.
On the correlation between ice water content and ice crystal size and its application to radiative analysis involving ice water content (IWC) and mean effective ice crystal size (De) intended, K. N., Y. Gu, Q. Yue, and G. McFarguhar (2008), On the correlation between ice water content and ice
Ionizing and ultraviolet radiation enhances the efficiency of DNA mediated gene transfer in vitro
Perez, C.F.
1984-08-01T23:59:59.000Z
The enhancement effects of ionizing and non-ionizing radiation on the efficiency of DNA mediated gene transfer were studied. Confluent Rat-2 cells were transfected with purified SV40 viral DNA, irradiated with either X-rays or ultraviolet, trypsinized, plated, and assayed for the formation of foci on Rat-2 monolayers. Both ionizing and ultraviolet radiation enhanced the frequency of A-gene transformants/survivor compared to unirradiated transfected cells. These enhancements were non-linear and dose dependent. A recombinant plasmid, pOT-TK5, was constructed that contained the SV40 virus A-gene and the Herpes Simplex virus (HSV) thymidine kinase (TK) gene. Confluent Rat-2 cells transfected with pOT-TK5 DNA and then immediately irradiated with either X-rays or 330 MeV/amu argon particles at the Berkeley Bevalac showed a higher frequency of HAT/sup +/ colonies/survivor than unirradiated transfected cells. Rat-2 cells transfected with the plasmid, pTK2, containing only the HSV TK-gene were enhanced for TK-transformation by both X-rays and ultraviolet radiation. The results demonstrate that radiation enhancement of the efficiency of DNA mediated gene transfer is not explained by increased nuclear uptake of the transfected DNA. Radiation increases the competence of the transfected cell population for genetic transformation. Three models for this increased competence are presented. The targeted integration model, the inducible recombination model, the partition model, and the utilization of DNA mediated gene transfer for DNA repair studies are discussed. 465 references.
Hogan, Robin
Incorporating the Effects of 3D Radiative Transfer in the Presence of Clouds into Two. The 3D effect on shortwave cloud radiative forcing varies between around 225% and around 1100. Therefore, cumulus clouds are of particular im- portance when considering 3D radiative effects: although
Fresnel Effect in Radiation Transfer in Biological Tissues Kyunghan Kim and Zhixiong Guo*
Guo, Zhixiong "James"
Fresnel Effect in Radiation Transfer in Biological Tissues Kyunghan Kim and Zhixiong Guo* MAE Method (DOM) to incorporate Fresnel's boundary in laser radiation transport in biological tissues is calculated by the use of Snell's law and Fresnel's equation. The radiation fields, including the radiative
RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS
Guo, Zhixiong "James"
RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS Kyunghan Kim to incorporate transient radiation heat transfer in tissue welding and soldering with use of ultrafast lasers are performed between laser welding and laser soldering. The use of solder is found to substantially enhance
Robert, Pincus
A fast, flexible, approximate technique for computing radiative transfer in inhomogeneous cloud.-J. Morcrette, A fast, flexible, approximate technique for computing radiative transfer in inhomogeneous cloud, which computes fluxes at each level. [3] The description of clouds in current LSMs is quite simple: Most
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Davis, Anthony B.; Xu, Feng; Collins, William D.
2015-03-01T23:59:59.000Z
Atmospheric hyperspectral VNIR sensing struggles with sub-pixel variability of clouds and limited spectral resolution mixing molecular lines. Our generalized radiative transfer model addresses both issues with new propagation kernels characterized by power-law decay in space.
Radiative heat transfer in anisotropic many-body systems: Tuning and enhancement
Nikbakht, Moladad, E-mail: mnik@znu.ac.ir [Department of Physics, Faculty of Sciences, University of Zanjan, Zanjan 45371-38791 (Iran, Islamic Republic of)
2014-09-07T23:59:59.000Z
A general formalism for calculating the radiative heat transfer in many body systems with anisotropic component is presented. Our scheme extends the theory of radiative heat transfer in isotropic many body systems to anisotropic cases. In addition, the radiative heating of the particles by the thermal bath is taken into account in our formula. It is shown that the radiative heat exchange (HE) between anisotropic particles and their radiative cooling/heating (RCH) could be enhanced several order of magnitude than that of isotropic particles. Furthermore, we demonstrate that both the HE and RCH can be tuned dramatically by particles relative orientation in many body systems.
Backbone Additivity in the Transfer Model of Protein Solvation...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Solvation. Abstract: The transfer model implying additivity of the peptide backbone free energy of transfer is computationally tested. Molecular dynamics simulations are used...
Robert, Pincus
The Accuracy of Determining Three-Dimensional Radiative Transfer Effects in Cumulus Clouds Using. Three-dimensional radiative transfer effects and why one might estimate them in two-dimensional clouds expensive independent column approximation is called the 3D radiative transfer effect. Assessing
Tafreshi, Hooman Vahedi
Analytical Monte Carlo Ray Tracing simulation of radiative heat transfer through bimodal fibrous-state radiative heat transfer through fibrous insulation materials. The simulations are conducted in 3-D disor radiation and conduc- tion to be the only modes of heat transfer in fibrous insulation materials
Phung, Kim-dang.- Le Laboratoire de MathÃ©matiques
I: Heat equation II: SchrÃ¶dinger equation III: Wave equation IV: Radiative transfer equation;I: Heat equation II: SchrÃ¶dinger equation III: Wave equation IV: Radiative transfer equation QUCP: Heat equation II: SchrÃ¶dinger equation III: Wave equation IV: Radiative transfer equation QUCP
Multi--dimensional Cosmological Radiative Transfer with a Variable Eddington Tensor Formalism
Nickolay Y. Gnedin; Tom Abel
2001-06-15T23:59:59.000Z
We present a new approach to numerically model continuum radiative transfer based on the Optically Thin Variable Eddington Tensor (OTVET) approximation. Our method insures the exact conservation of the photon number and flux (in the explicit formulation) and automatically switches from the optically thick to the optically thin regime. It scales as N logN with the number of hydrodynamic resolution elements and is independent of the number of sources of ionizing radiation (i.e. works equally fast for an arbitrary source function). We also describe an implementation of the algorithm in a Soften Lagrangian Hydrodynamic code (SLH) and a multi--frequency approach appropriate for hydrogen and helium continuum opacities. We present extensive tests of our method for single and multiple sources in homogeneous and inhomogeneous density distributions, as well as a realistic simulation of cosmological reionization.
RADIATIVE TRANSFER SIMULATIONS OF NEUTRON STAR MERGER EJECTA
Tanaka, Masaomi [National Astronomical Observatory of Japan, Mitaka, Tokyo (Japan); Hotokezaka, Kenta, E-mail: masaomi.tanaka@nao.ac.jp, E-mail: hotoke@tap.scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto (Japan)
2013-10-01T23:59:59.000Z
Mergers of binary neutron stars (NSs) are among the most promising gravitational wave (GW) sources. Next generation GW detectors are expected to detect signals from NS mergers within about 200 Mpc. The detection of electromagnetic wave (EM) counterparts is crucial to understanding the nature of GW sources. Among the possible EM emission from the NS merger, emission powered by radioactive r-process nuclei is one of the best targets for follow-up observations. However, predictions so far have not taken into account detailed r-process element abundances in the ejecta. We perform for the first time radiative transfer simulations of the NS merger ejecta including all the r-process elements from Ga to U. We show that the opacity of the NS merger ejecta is about ? = 10 cm{sup 2} g{sup –1}, which is higher than that of Fe-rich Type Ia supernova ejecta by a factor of ?100. As a result, the emission is fainter and lasts longer than previously expected. The spectra are almost featureless due to the high expansion velocity and bound-bound transitions of many different r-process elements. We demonstrate that the emission is brighter for a higher mass ratio of the two NSs and a softer equation of state adopted in the merger simulations. Because of the red color of the emission, follow-up observations in red optical and near-infrared (NIR) wavelengths will be the most efficient. At 200 Mpc, the expected brightness of the emission is i = 22-25 AB mag, z = 21-23 AB mag, and 21-24 AB mag in the NIR JHK bands. Thus, observations with wide-field 4 m- and 8 m-class optical telescopes and wide-field NIR space telescopes are necessary. We also argue that the emission powered by radioactive energy can be detected in the afterglow of nearby short gamma-ray bursts.
Graphene-assisted near-field radiative heat transfer between corrugated polar materials
Liu, X. L.; Zhang, Z. M., E-mail: zhuomin.zhang@me.gatech.edu [G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)
2014-06-23T23:59:59.000Z
Graphene has attracted great attention in nanoelectronics, optics, and energy harvesting. Here, the near-field radiative heat transfer between graphene-covered corrugated silica is investigated based on the exact scattering theory. It is found that graphene can improve the radiative heat flux between silica gratings by more than one order of magnitude and alleviate the performance sensitivity to lateral shift. The underlying mechanism is mainly attributed to the improved photon tunneling of modes away from phonon resonances. Besides, coating with graphene leads to nonlocal radiative transfer that breaks Derjaguin's proximity approximation and enables corrugated silica to outperform bulk silica in near-field radiation.
Near-field thermal radiation transfer controlled by plasmons in graphene
Ilic, Ognjen
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 ...
Electrically tunable near-field radiative heat transfer via ferroelectric materials
Huang, Yi
We explore ways to actively control near-field radiative heat transfer between two surfaces that relies on electrical tuning of phonon modes of ferroelectric materials. Ferroelectrics are widely used for tunable electrical ...
Ko, Min Seok
2009-05-15T23:59:59.000Z
This dissertation presents a numerical simulation of three-dimensional flow and heat transfer in a channel with a backward-facing step. Flow was considered to be steady, incompressible, and laminar. The flow medium was treated to be radiatively...
Radiative transfer in the earth's atmosphere-ocean system using Monte Carlo techniques
Bradley, Paul Andrew
1987-01-01T23:59:59.000Z
and ocean has numerous important implications in the fields of mete- orology, oceanography, and physics. One recent example of the power oi radiative transfer theory in studying the Earth's atmosphere is the discovery of the "nuclear winter" phenomenon...
Efficient weakly-radiative wireless energy transfer: An EIT-like approach
Hamam, Rafif E.
Inspired by a quantum interference phenomenon known in the atomic physics community as electromagnetically induced transparency (EIT), we propose an efficient weakly radiative wireless energy transfer scheme between two ...
O Star X-ray Line Profiles Explained by Radiation Transfer in Inhomogeneous Stellar Wind
L. M. Oskinova; A. Feldmeier; W. -R. Hamann
2005-11-01T23:59:59.000Z
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.
Paris-Sud XI, Université de
-cooled reactor. It is typically made of many prismatic blocks of graphite in which are inserted the nuclear fuel in the homogenization of heat transfer in periodic porous media where the fluid part is made of long thin parallel in the solid part of the domain and by conduction, convection and radiative transfer in the fluid part (the
Radiation heat transfer in multitube, alkaline-metal thermal-to-electric converter
Tournier, J.M.P.; El-Genk, M.S. [Univ. of New Mexico, Albuquerque, NM (United States)
1999-02-01T23:59:59.000Z
Vapor anode, multitube Alkali-Metal Thermal-to-Electric Converters (AMTECs) are being considered for a number of space missions, such as the NASA Pluto/Express (PX) and Europa missions, scheduled for the years 2004 and 2005, respectively. These static converters can achieve a high fraction of Carnot efficiency at relatively low operating temperatures. An optimized cell can potentially provide a conversion efficiency between 20 and 30 percent, when operated at a hot-side temperature of 1000--1200 K and a cold-side temperature of 550--650 K. A comprehensive modeling and testing program of vapor anode, multitube AMTEC cells has been underway for more than three years at the Air Force Research Laboratory`s Power and Thermal Group (AFRL/VSDVP), jointly with the University of New Mexico`s Institute for Space and Nuclear Power Studies. The objective of this program is to demonstrate the readiness of AMTECs for flight on future US Air Force space missions. A fast, integrated AMTEC Performance and Evaluation Analysis Model (APEAM) has been developed to support ongoing vacuum tests at AFRL and perform analyses and investigate potential design changes to improve the PX-cell performance. This model consists of three major components (Tournier and El-Genk 1998a, b): (a) a sodium vapor pressure loss model, which describes continuum, transition and free-molecule flow regimes in the low-pressure cavity of the cell; (b) an electrochemical and electrical circuit model; and (c) a radiation/conduction heat transfer model, for calculating parasitic heat losses. This Technical Note describes the methodology used to calculate the radiation view factors within the enclosure of the PX-cells, and the numerical procedure developed in this work to determine the radiation heat transport and temperatures within the cell cavity.
Radiative Transfer in the Midwave Infrared Applicable to Full Spectrum Atmospheric
Kerekes, John
of the radiative effects in the MWIR is needed. The MWIR is characterized by a unique combination of reduced solar conditions are stressing (e.g., high moisture, heavy aerosol/particulate loading, partial cloud cover, lowRadiative Transfer in the Midwave Infrared Applicable to Full Spectrum Atmospheric Characterization
A Coupled AtmosphereOcean Radiative Transfer System Using the Analytic Four-Stream Approximation
Liou, K. N.
of the ocean. Shortwave radiation from the sun contributes most of the heat fluxes that penetrate the airA Coupled AtmosphereOcean Radiative Transfer System Using the Analytic Four-Stream Approximation WEI-LIANG LEE AND K. N. LIOU Department of Atmospheric and Oceanic Sciences, University of California
Guo, Zhixiong "James"
Equivalent isotropic scattering formulation for transient short-pulse radiative transfer of the transient short-pulse radiation transport through forward and backward anisotropic scattering planar media applications to such systems as industrial furnaces, combustion cham- bers, fibrous and porous insulations
Radiative heat transfer in a parallelogram shaped cavity
Dez, V Le
2015-01-01T23:59:59.000Z
An exact analytical description of the internal radiative field inside an emitting-absorbing gray semi-transparent medium enclosed in a two-dimensional parallelogram cavity is proposed. The expressions of the incident radiation and the radiative flux field are angularly and spatially discretized with a double Gauss quadrature, and the temperature field is obtained by using an iterative process. Some numerical solutions are tabulated and graphically presented as the benchmark solutions. Temperature and two components of the radiative flux are finally sketched on the whole domain. It is shown that the proposed method gives perfectly smooth results.
A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS WITH
A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS WITH ATTACHED WALL JETS By WEIXIU KONGQuest Information and Learning Company. #12;II A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS
Density Functional Theory Models for Radiation Damage
Density Functional Theory Models for Radiation Damage S.L. Dudarev EURATOM/CCFE Fusion Association and informative as the most advanced experimental techniques developed for the observation of radiation damage investigation and assessment of radiation damage effects, offering new insight into the origin of temperature
Matthias Krüger; Giuseppe Bimonte; Thorsten Emig; Mehran Kardar
2012-07-16T23:59:59.000Z
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.
Influence of Infrared Radiation on Attic Heat Transfer
Katipamula, S.; Turner, W. D.; Murphy, W. E.; O'Neal, D. L.
1985-01-01T23:59:59.000Z
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...
Stephens, Graeme L.
in downwelling radiative fluxes at the surface induced by changes in cloud cover and water vapor distributions. 1An Assessment of the Parameterization of Subgrid-Scale Cloud Effects on Radiative Transfer. Part II form 5 January 2005) ABSTRACT The role of horizontal inhomogeneity in radiative transfer through cloud
Cerveny, Vlastislav
1994-01-01T23:59:59.000Z
of radiative heat transfer on the formation of megaplumes in the lower mantle Ctirad Matyska a, Ji~i Moser influence from radiative heat transfer on mantle upwellings and the production of extremely hot thermal and cold regions in lower mantle dynamics. We have considered the possible impact from radiative heat
Henri PoincarÃ© -Nancy-UniversitÃ©, UniversitÃ©
. Introduction And Main Results Radiative heat transfer coupled with conduction through semi---transparent media---state combined radiative---conductive heat transfer. The media studied were assumed to be homogeneous, grey1 CONVERGENCE OF A NUMERICAL SCHEME FOR A NONLINEAR COUPLED SYSTEM OF RADIATIVE---CONDUCTIVE HEAT
Journal of Quantitative Spectroscopy & Radiative Transfer 99 (2006) 341348
2006-01-01T23:59:59.000Z
). 1 Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin CompanyV blackbody-like radiators [3] are presently used for inertial confinement fusion studies and other work
Radiative component and combined heat transfer in the thermal calculation of finned tube banks
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
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.
A new nonlocal thermodynamical equilibrium radiative transfer method for cool stars
Lambert, Julien; Ryde, Nils; Faure, Alexandre
2015-01-01T23:59:59.000Z
Context: The solution of the nonlocal thermodynamical equilibrium (non-LTE) radiative transfer equation usually relies on stationary iterative methods, which may falsely converge in some cases. Furthermore, these methods are often unable to handle large-scale systems, such as molecular spectra emerging from, for example, cool stellar atmospheres. Aims: Our objective is to develop a new method, which aims to circumvent these problems, using nonstationary numerical techniques and taking advantage of parallel computers. Methods: The technique we develop may be seen as a generalization of the coupled escape probability method. It solves the statistical equilibrium equations in all layers of a discretized model simultaneously. The numerical scheme adopted is based on the generalized minimum residual method. Result:. The code has already been applied to the special case of the water spectrum in a red supergiant stellar atmosphere. This demonstrates the fast convergence of this method, and opens the way to a wide va...
Modeling the comfort effects of short-wave solar radiation indoors
Arens, Edward; Hoyt, Tyler; Zhou, Xin; Huang, Li; Zhang, Hui; Schiavon, Stefano
2015-01-01T23:59:59.000Z
7]); h r is the radiation heat transfer coefficient (W/m 2Unit °C W/m 2 h r Radiation heat transfer coefficient W/m
Heat transfer including radiation and slag particles evolution in MHD channel-I
Im, K.H.; Ahluwalia, R.K.
1980-01-01T23:59:59.000Z
Accurate estimates of convective and radiative heat transfer in the magnetohydrodynamic channel are provided. Calculations performed for a base load-size channel indicate that heat transfer by gas radiation almost equals that by convection for smooth walls, and amounts to 70% as much as the convective heat transfer for rough walls. Carbon dioxide, water vapor, and potassium atoms are the principal participating gases. The evolution of slag particles by homogeneous nucleation and condensation is also investigated. The particle-size spectrum so computed is later utilized to analyze the radiation enhancement by slag particles in the MHD diffuser. The impact of the slag particle spectrum on the selection of a workable and design of an efficient seed collection system is discussed.
Journal of Quantitative Spectroscopy & Radiative Transfer 93 (2005) 163173
Xu, Xianfan
2005-01-01T23:59:59.000Z
to fabricate nano-structures, optical data storage to reach ultra-high storage density, heat assisted magnetic concentrated in the gap between the ridges, which provides the electric dipole-liked behavior. The optimal of radiation according to Huygens principle. If the aperture is large in size in comparison with wavelength
Radiative Transfer in Interacting Media J.Kenneth Shultis
Shultis, J. Kenneth
can a ect the uid ow e.g., shock phenomena, energy loss from thermonuclear plasmas, combustion studies accelerated by neutron and high-energy photon transport methods for both military and civilian applications of nuclear energy. Today, radiative transport plays an important role in many other areas besides nuclear
Re ectance comparison between SCIAMACHY and a radiative transfer code in the UV
Tilstra, Gijsbert
Kon i nk l i j k Neder l ands Meteoro l og i sch Inst i tuut Re#29;ectance comparison between SCIAMACHY and a radiative transfer code in the UV L.G. Tilstra, G. van Soest, M. de Graaf, J.R. Acarreta, P#21;2400 nm. We compare its re#29;ectance mea- surements in the UV with calculations by a polarised radiative
Incorporation of 3D Shortwave Radiative Effects within the Weather Research and Forecasting Model
O'Hirok, W.; Ricchiazzi, P.; Gautier, C.
2005-03-18T23:59:59.000Z
A principal goal of the Atmospheric Radiation Measurement (ARM) Program is to understand the 3D cloud-radiation problem from scales ranging from the local to the size of global climate model (GCM) grid squares. For climate models using typical cloud overlap schemes, 3D radiative effects are minimal for all but the most complicated cloud fields. However, with the introduction of ''superparameterization'' methods, where sub-grid cloud processes are accounted for by embedding high resolution 2D cloud system resolving models within a GCM grid cell, the impact of 3D radiative effects on the local scale becomes increasingly relevant (Randall et al. 2003). In a recent study, we examined this issue by comparing the heating rates produced from a 3D and 1D shortwave radiative transfer model for a variety of radar derived cloud fields (O'Hirok and Gautier 2005). As demonstrated in Figure 1, the heating rate differences for a large convective field can be significant where 3D effects produce areas o f intense local heating. This finding, however, does not address the more important question of whether 3D radiative effects can alter the dynamics and structure of a cloud field. To investigate that issue we have incorporated a 3D radiative transfer algorithm into the Weather Research and Forecasting (WRF) model. Here, we present very preliminary findings of a comparison between cloud fields generated from a high resolution non-hydrostatic mesoscale numerical weather model using 1D and 3D radiative transfer codes.
Aller, M F; Aller, H D; Latimer, G E; Hovatta, T
2014-01-01T23:59:59.000Z
To investigate parsec-scale jet flow conditions during GeV gamma-ray flares detected by the Fermi Large Angle Telescope, we obtained centimeter-band total flux density and linear polarization monitoring observations from 2009.5 through 2012.5 with the 26-meter Michigan radio telescope for a sample of core-dominated blazars. We use these data to constrain radiative transfer simulations incorporating propagating shocks oriented at an arbitrary angle to the flow direction in order to set limits on the jet flow and shock parameters during flares temporally associated with gamma-ray flares in 0420-014, OJ 287, and 1156+295; these AGN exhibited the expected signature of shocks in the linear polarization data. Both the number of shocks comprising an individual radio outburst (3-4) and the range of the compression ratios of the individual shocks (0.5-0.8) are similar in all three sources; the shocks are found to be forward-moving with respect to the flow. While simulations incorporating transverse shocks provide good...
The dynamic radiation environment assimilation model (DREAM)
Reeves, Geoffrey D [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Tokar, Robert L [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory; Friedel, Reiner H [Los Alamos National Laboratory
2010-01-01T23:59:59.000Z
The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.
Multiscale Modeling of Radiation Damage in
Multiscale Modeling of Radiation Damage in Fusion Reactor Materials Brian D. Wirth, R.J. Kurtz-7405-Eng-48. #12;Presentation overview · Introduction to fusion reactor materials and radiation damage. tailor He HFIR isotopic tailor He HFIR target/RB He appmHe displacement damage (dpa) ffuussiioonn
Helium Reionization Simulations. I. Modeling Quasars as Radiation Sources
La Plante, Paul
2015-01-01T23:59:59.000Z
We introduce a new project to understand helium reionization using fully coupled $N$-body, hydrodynamics, and radiative transfer simulations. This project aims to capture correctly the thermal history of the intergalactic medium (IGM) as a result of reionization and make predictions about the Lyman-$\\alpha$ forest and baryon temperature-density relation. The dominant sources of radiation for this transition are quasars, so modeling the source population accurately is very important for making reliable predictions. In this first paper, we present a new method for populating dark matter halos with quasars. Our set of quasar models include two different light curves, a lightbulb (simple on/off) and symmetric exponential model, and luminosity-dependent quasar lifetimes. Our method self-consistently reproduces an input quasar luminosity function (QLF) given a halo catalog from an $N$-body simulation, and propagates quasars through the merger history of halo hosts. After calibrating quasar clustering using measurem...
ARM - Publications: Science Team Meeting Documents: ARM Radiative Transfer
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirtA JourneygovCampaignsPajaritogovFieldMapping ofAand Radiative Forcing CloudsValidation of
Sensitivity Analysis of the Gap Heat Transfer Model in BISON.
Swiler, Laura Painton; Schmidt, Rodney C.; Williamson, Richard (INL); Perez, Danielle (INL)
2014-10-01T23:59:59.000Z
This report summarizes the result of a NEAMS project focused on sensitivity analysis of the heat transfer model in the gap between the fuel rod and the cladding used in the BISON fuel performance code of Idaho National Laboratory. Using the gap heat transfer models in BISON, the sensitivity of the modeling parameters and the associated responses is investigated. The study results in a quantitative assessment of the role of various parameters in the analysis of gap heat transfer in nuclear fuel.
High-energy radiation damage in zirconia: modeling results ....
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energy radiation damage in zirconia: modeling results . High-energy radiation damage in zirconia: modeling results . Abstract: Zirconia has been viewed as a material of exceptional...
Decomposition of radiational effects of model feedbacks
Ellsaesser, H.W.; MacCracken, M.C.; Potter, G.L.; Mitchell, C.S.
1981-08-01T23:59:59.000Z
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.
Liberman, M A; Kiverin, A D
2015-01-01T23:59:59.000Z
In this study we examine influence of the radiation heat transfer on the combustion regimes in the mixture, formed by suspension of fine inert particles in hydrogen gas. The gaseous phase is assumed to be transparent for the thermal radiation, while the radiant heat absorbed by the particles is then lost by conduction to the surrounding gas. The particles and gas ahead of the flame is assumed to be heated by radiation from the original flame. It is shown that the maximum temperature increase due to the radiation preheating becomes larger for a flame with lower velocity. For a flame with small enough velocity temperature of the radiation preheating may exceed the crossover temperature, so that the radiation heat transfer may become a dominant mechanism of the flame propagation. In the case of non-uniform distribution of particles, the temperature gradient formed due to the radiation preheating can initiate either deflagration or detonation ahead of the original flame via the Zel'dovich's gradient mechanism. Th...
Shape-independent limits to near-field radiative heat transfer
Miller, Owen D; Rodriguez, Alejandro W
2015-01-01T23:59:59.000Z
We derive shape-independent limits to the spectral radiative heat-transfer rate between two closely spaced bodies, generalizing the concept of a black body to the case of near-field energy transfer. By conservation of energy, we show that each body of susceptibility $\\chi$ can emit and absorb radiation at enhanced rates bounded by $|\\chi|^2 / \\operatorname{Im} \\chi$, optimally mediated by near-field photon transfer proportional to $1/d^2$ across a separation distance $d$. Dipole--dipole and dipole--plate structures approach restricted versions of the limit, but common large-area structures do not exhibit the material enhancement factor and thus fall short of the general limit. By contrast, we find that particle arrays interacting in an idealized Born approximation exhibit both enhancement factors, suggesting the possibility of orders-of-magnitude improvement beyond previous designs and the potential for radiative heat transfer to be comparable to conductive heat transfer through air at room temperature, and s...
Influence of Infrared Radiation on Attic Heat Transfer
Katipamula, S.; Turner, W. D.; Murphy, W. E.; O'Neal, D. L.
1985-01-01T23:59:59.000Z
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...
Radiative transfer and thermal performance levels in foam insulation boardstocks
Moreno, John David
1991-01-01T23:59:59.000Z
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 ...
Proceedings of HT2009 2009 ASME Summer Heat Transfer Conference
Guo, Zhixiong "James"
-dependent radiation and conduction bio-heat transfer model. Ultrashort pulsed radiation transport in the cylindrical a combined transient heat transfer and Pennes bio-heat transfer model is developed to simulate the heat transfer models; and concluded that the Pennes model is still the most practical for fast prediction
Alan P. Boss
2008-12-12T23:59:59.000Z
The disk instability mechanism for giant planet formation is based on the formation of clumps in a marginally-gravitationally unstable protoplanetary disk, which must lose thermal energy through a combination of convection and radiative cooling if they are to survive and contract to become giant protoplanets. While there is good observational support for forming at least some giant planets by disk instability, the mechanism has become theoretically contentious, with different three dimensional radiative hydrodynamics codes often yielding different results. Rigorous code testing is required to make further progress. Here we present two new analytical solutions for radiative transfer in spherical coordinates, suitable for testing the code employed in all of the Boss disk instability calculations. The testing shows that the Boss code radiative transfer routines do an excellent job of relaxing to and maintaining the analytical results for the radial temperature and radiative flux profiles for a spherical cloud with high or moderate optical depths, including the transition from optically thick to optically thin regions. These radial test results are independent of whether the Eddington approximation, diffusion approximation, or flux-limited diffusion approximation routines are employed. The Boss code does an equally excellent job of relaxing to and maintaining the analytical results for the vertical (theta) temperature and radiative flux profiles for a disk with a height proportional to the radial distance. These tests strongly support the disk instability mechanism for forming giant planets.
Efficient weakly-radiative wireless energy transfer: An EIT-like approach
Hamam, Rafif E. [Center for Materials Science and Engineering and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)], E-mail: rafif@mit.edu; Karalis, Aristeidis; Joannopoulos, J.D.; Soljacic, Marin [Center for Materials Science and Engineering and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
2009-08-15T23:59:59.000Z
Inspired by a quantum interference phenomenon known in the atomic physics community as electromagnetically induced transparency (EIT), we propose an efficient weakly radiative wireless energy transfer scheme between two identical classical resonant objects, strongly coupled to an intermediate classical resonant object of substantially different properties, but with the same resonance frequency. The transfer mechanism essentially makes use of the adiabatic evolution of an instantaneous (so called 'dark') eigenstate of the coupled 3-object system. Our analysis is based on temporal coupled mode theory (CMT), and is general enough to be valid for various possible sorts of coupling, including the resonant inductive coupling on which witricity-type wireless energy transfer is based. We show that in certain parameter regimes of interest, this scheme can be more efficient, and/or less radiative than other, more conventional approaches. A concrete example of wireless energy transfer between capacitively-loaded metallic loops is illustrated at the beginning, as a motivation for the more general case. We also explore the performance of the currently proposed EIT-like scheme, in terms of improving efficiency and reducing radiation, as the relevant parameters of the system are varied.
2D radiative modelling of He I spectral lines formed in solar prominences
L. Leger; F. Paletou
2008-07-11T23:59:59.000Z
We present preliminary results of 2D radiative modelling of He I lines in solar prominences, using a new numerical code developed by us (Leger, Chevallier and Paletou 2007). It treats self-consistently the radiation transfer and the non-LTE statistical equilibrium of H and, in a second stage, the one of He using a detailed atomic model. Preliminary comparisons with new visible plus near-infrared observations made at high spectral resolution with THeMIS are very satisfactory.
Dr. Lazaros Oreopoulos and Dr. Peter M. Norris
2010-03-14T23:59:59.000Z
The overarching goal of the project was to improve the transfer of solar and thermal radiation in the most sophisticated computer tools that are currently available for climate studies, namely Global Climate Models (GCMs). This transfer can be conceptually separated into propagation of radiation under cloudy and under cloudless conditions. For cloudless conditions, the factors that affect radiation propagation are gaseous absorption and scattering, aerosol particle absorption and scattering and surface albedo and emissivity. For cloudy atmospheres the factors are the various cloud properties such as cloud fraction, amount of cloud condensate, the size of the cloud particles, and morphological cloud features such as cloud vertical location, cloud horizontal and vertical inhomogeneity and cloud shape and size. The project addressed various aspects of the influence of the above contributors to atmospheric radiative transfer variability. In particular, it examined: (a) the quality of radiative transfer for cloudless and non-complex cloudy conditions for a substantial number of radiation algorithms used in current GCMs; (b) the errors in radiative fluxes from neglecting the horizontal variabiity of cloud extinction; (c) the statistical properties of cloud horizontal and vertical cloud inhomogeneity that can be incorporated into radiative transfer codes; (d) the potential albedo effects of changes in the particle size of liquid clouds; (e) the gaseous radiative forcing in the presence of clouds; and (f) the relative contribution of clouds of different sizes to the reflectance of a cloud field. To conduct the research in the various facets of the project, data from both the DOE ARM project and other sources were used. The outcomes of the project will have tangible effects on how the calculation of radiative energy will be approached in future editions of GCMs. With better calculations of radiative energy in GCMs more reliable predictions of future climate states will be attainable, thus affecting public policy decisions with great impact to public life.
Wellbore Heat Transfer Model for Wax Deposition in Permafrost Region
Cui, Xiaoting
2012-05-31T23:59:59.000Z
Producing waxy oil in arctic area may cause wax deposited on the well wall. Since wax deposition is strongly thermal related, accurate heat transfer model is necessary in predicting and preventing wax depostion. A mathematical model was derived...
Lyalpha RADIATIVE TRANSFER WITH DUST: ESCAPE FRACTIONS FROM SIMULATED HIGH-REDSHIFT GALAXIES
Laursen, Peter; Sommer-Larsen, Jesper; Andersen, Anja C., E-mail: pela@dark-cosmology.d, E-mail: jslarsen@astro.ku.d [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen Oe (Denmark)
2009-10-20T23:59:59.000Z
The Lyalpha emission line is an essential diagnostic tool for probing galaxy formation and evolution. Not only is it commonly the strongest observable line from high-redshift galaxies, but from its shape detailed information about its host galaxy can be revealed. However, due to the scattering nature of Lyalpha photons increasing their path length in a nontrivial way, if dust is present in the galaxy, the line may be severely suppressed and its shape altered. In order to interpret observations correctly, it is thus of crucial significance to know how much of the emitted light actually escapes the galaxy. In the present work, using a combination of high-resolution cosmological hydrosimulations and an adaptively refinable Monte Carlo Lyalpha radiative transfer code including an environment dependent model of dust, the escape fractions f {sub esc} of Lyalpha radiation from high-redshift (z = 3.6) galaxies are calculated. In addition to the average escape fraction, the variation of f {sub esc} in different directions and from different parts of the galaxies is investigated, as well as the effect on the emergent spectrum. Escape fractions from a sample of simulated galaxies of representative physical properties are found to decrease for increasing galaxy virial mass M {sub vir}, from f {sub esc} approaching unity for M {sub vir} approx 10{sup 9} M {sub sun} to f {sub esc} less than 10% for M {sub vir} approx 10{sup 12} M {sub sun}. In spite of dust being almost gray, it is found that the emergent spectrum is affected nonuniformly, with the escape fraction of photons close to the line center being much higher than of those in the wings, thus effectively narrowing the Lyalpha line.
Heat transfer and oil displacement models for tar sands reservoirs
Ward, C.E.; Ward, G.D.
1984-09-01T23:59:59.000Z
A convective heat transfer model and one dimensional displacement model applicable to tar sands and heavy oils for use with a microcomputer are presented. The convective heat transfer model describes the temperature profiles in a thermal operation. The displacement model offers insight into the effect of process variables on the steam/oil or air/oil ratio of thermal operations. A method is presented for predicting the fuel burn in a fireflood.
A new scheme of radiation transfer in H II regions including transient heating of grains
S. K. Ghosh; R. P. Verma
2000-09-21T23:59:59.000Z
A new scheme of radiation transfer for understanding infrared spectra of H II regions, has been developed. This scheme considers non-equilibrium processes (e. g. transient heating of the very small grains, VSG; and the polycyclic aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal emission from normal dust grains (BG). The spherically symmetric interstellar dust cloud is segmented into a large number of "onion skin" shells in order to implement the non-equilibrium processes. The scheme attempts to fit the observed SED originating from the dust component, by exploring the following parameters : (i) geometrical details of the dust cloud, (ii) PAH size and abundance, (iii) composition of normal grains (BG), (iv) radial distribution of all dust (BG, VSG & PAH). The scheme has been applied to a set of five compact H II regions (IRAS 18116- 1646, 18162-2048, 19442+2427, 22308+5812 & 18434-0242) whose spectra are available with adequate spectral resolution. The best fit models and inferences about the parameters for these sources are presented.
Yuen, Walter W.
-gray radiative heat transfer effect in three-dimensional gas-particle mixtures Walter W. Yuen * Department to assess the accuracy of some commonly accepted approximate approaches to evaluate radiative heat transfer enhance the accuracy of simulation of radiative heat transfer in practical engineering systems. Ó 2009
Mills, Peter
2012-01-01T23:59:59.000Z
Microwave emissivity models of sea ice are poorly validated empirically. Typical validation studies involve using averaged or stereotyped profiles of ice parameters against averaged radiance measurements. Measurement sites are rarely matched and even less often point-by-point. Because of saline content, complex permittivity of sea ice is highly variable and difficult to predict. Therefore, to check the validity of a typical, plane-parallel, radiative-transfer-based ice emissivity model, we apply it to fresh water ice instead of salt-water ice. Radiance simulations for lake ice are compared with measurements over Lake Superior from the Advanced Microwave Scanning Radiometer on EOS (AMSR-E). AMSR-E measurements are also collected over Antarctic icepack. For each pixel, a thermodynamic model is driven by four years of European Center for Medium Range Weather Forecasts (ECMWF) reanalysis data and the resulting temperature profiles used to drive the emissivity model. The results suggest that the relatively simple ...
Svend-Age Biehs
2011-03-15T23:59:59.000Z
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.
Non-contact pumping of light emitters via non-radiative energy transfer
Klimov, Victor I. (Los Alamos, NM); Achermann, Marc (Los Alamos, NM)
2010-01-05T23:59:59.000Z
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.
Near-Field Radiative Heat Transfer between Metamaterials coated with Silicon Carbide Film
Basu, Soumyadipta; Wang, Liping
2014-01-01T23:59:59.000Z
In this letter, we study the near-field radiative heat transfer between two metamaterial substrates coated with silicon carbide (SiC) thin films. It is known that metamaterials can enhance the near-field heat transfer over ordinary materials due to excitation of magnetic plasmons associated with s polarization, while strong surface phonon polariton exists for SiC.By careful tuning of the optical properties of metamaterial it is possible to excite electrical and magnetic resonance for the metamaterial and surface phonon polaritons for SiC at different spectral regions, resulting in the enhanced heat transfer. The effect of the SiC film thickness at different vacuum gaps is investigated. Results obtained from this study will be beneficial for application of thin film coatings for energy harvesting.
which should be as simple as possible to be implemented in the combined heat transfer model. In general as a component of the multidimensional combined heat transfer model for soft thermal treatment of superficial
Joulain, Karl; Drevillon, Jeremie; Ben-Abdallah, Philippe
2015-01-01T23:59:59.000Z
We show in this article that phase change materials (PCM) exhibiting a phase transition between a dielectric state and a metallic state are good candidates to perform modulation as well as amplification of radiative thermal flux. We propose a simple situation in plane parallel geometry where a so-called radiative thermal transistor could be achieved. In this configuration, we put a PCM between two blackbodies at different temperatures. We show that the transistor effect can be achieved easily when this material has its critical temperature between the two blackbody temperatures. We also see, that the more the material is reflective in the metallic state, the more switching effect is realized whereas the more PCM transition is stiff in temperature, the more thermal amplification is high. We finally take the example of VO2 that exhibits an insulator-metallic transition at 68{\\textdegree}C. We show that a demonstrator of a radiative transistor could easily be achieved in view of the heat flux levels predicted. F...
Radiative charge transfer in cold and ultracold Sulfur atoms colliding with Protons
Shen, G; Wang, J G; McCann, J F; McLaughlin, B M
2015-01-01T23:59:59.000Z
Radiative decay processes at cold and ultra cold temperatures for Sulfur atoms colliding with protons are investigated. The MOLPRO quantum chemistry suite of codes was used to obtain accurate potential energies and transition dipole moments, as a function of internuclear distance, between low-lying states of the SH$^{+}$ molecular cation. A multi-reference configuration-interaction (MRCI) approximation together with the Davidson correction is used to determine the potential energy curves and transition dipole moments, between the states of interest, where the molecular orbitals (MO's) are obtained from state-averaged multi configuration-self-consistent field (MCSCF) calculations. The collision problem is solved approximately using an optical potential method to obtain radiative loss, and a fully two-channel quantum approach for radiative charge transfer. Cross sections and rate coefficients are determined for the first time for temperatures ranging from 10 $\\mu$ K up to 10,000 K. Results are obtained for all ...
cloud cover r.p.allan@reading.ac.uk© University of Reading 20108 #12;Radiative bias: climate models estimate radiative effect of contrail cirrus:contrail cirrus: LW ~ 40 Wm-2 SW up to 80 Wm-2 rUsing Geostationary Earth Radiation Budget dataUsing Geostationary Earth Radiation Budget data
A vectorized heat transfer model for solid reactor cores
Rider, W.J.; Cappiello, M.W.; Liles, D.R.
1990-01-01T23:59:59.000Z
The new generation of nuclear reactors includes designs that are significantly different from light water reactors. Among these new reactor designs is the Modular High-Temperature Gas-Cooled Reactor (MHTGR). In addition, nuclear thermal rockets share a number of similarities with terrestrial HTGRs and would be amenable to similar types of analyses. In these reactors, the heat transfer in the solid core mass is of primary interest in design and safety assessment. One significant safety feature of these reactors is the capability to withstand a loss of pressure and forced cooling in the primary system and still maintain peak fuel temperatures below the safe threshold for retaining the fission products. To accurately assess the performance of gas-cooled reactors during these types of transients, a Helium/Hydrogen Cooled Reactor Analysis (HERA) computer code has been developed. HERA has the ability to model arbitrary geometries in three dimensions, which allows the user to easily analyze reactor cores constructed of prismatic graphite elements. The code accounts for heat generation in the fuel, control rods and other structures; conduction and radiation across gaps; convection to the coolant; and a variety of boundary conditions. The numerical solution scheme has been optimized for vector computers, making long transient analyses economical. Time integration is either explicit or implicit, which allows the use of the model to accurately calculate both short- or long-term transients with an efficient use of computer time. Both the basic spatial and temporal integration schemes have been benchmarked against analytical solutions. Also, HERA has been used to analyze a depressurized loss of forced cooling transient in a HTGR with a very detailed three-dimensional input model. The results compare favorably with other means of analysis and provide further validation of the models and methods. 18 refs., 11 figs.
Soljaèiæ, Marin
2012-01-01T23:59:59.000Z
in graphene Ognjen Ilic,1,* Marinko Jablan,2 John D. Joannopoulos,1 Ivan Celanovic,3 Hrvoje Buljan,2 and Marin-field radiation transfer between two closely separated graphene sheets. The dependence of near-field heat exchange interband or intraband processes. We predict maximum transfer at low doping and for plasmons in two graphene
Modeling of Heat Transfer in Rooms in the Modelica Buildings Library
Wetter, Michael
2013-01-01T23:59:59.000Z
of the room heat transfer model in the free open-sourcea layer-by-layer heat transfer model that computes infrared
Boyer, Edmond
Eurotherm Seminar N°81 Reactive Heat Transfer in Porous Media, Ecole des Mines d'Albi, France June 4-6, 2007 ET81- 1 HEAT TRANSFER BY SIMULTANEOUS RADIATION-CONDUCTION AND CONVECTION IN A HIGH for the packed bed. The comparison between the radiative heat transfer and the exchanges by conduction and forced
Investigation of Radiation and Chemical Resistance of Flexible HLW Transfer Hose
E. Skidmore; Billings, K.; Hubbard, M.
2010-03-24T23:59:59.000Z
A chemical transfer hose constructed of an EPDM (ethylene-propylene diene monomer) outer covering with a modified cross-linked polyethylene (XLPE) lining was evaluated for use in high level radioactive waste transfer applications. Laboratory analysis involved characterization of the hose liner after irradiation to doses of 50 to 300 Mrad and subsequent exposure to 25% NaOH solution at 93 C for 30 days, simulating 6 months intermittent service. The XLPE liner mechanical and structural properties were characterized at varying dose levels. Burst testing of irradiated hose assemblies was also performed. Literature review and test results suggest that radiation effects below doses of 100 kGy are minimal, with acceptable property changes to 500 kGy. Higher doses may be feasible. At a bounding dose of 2.5 MGy, the burst pressure is reduced to the working pressure (1.38 MPa) at room temperature. Radiation exposure slightly reduces liner tensile strength, with more significant decrease in liner elongation. Subsequent exposure to caustic solutions at elevated temperature slightly increases elongation, suggesting an immersion/hydrolytic effect or possible thermal annealing of radiation damage. This paper summarizes the laboratory results and recommendations for field deployment.
Hodgkiss, Justin M. (Justin Mark), 1978-
2007-01-01T23:59:59.000Z
Time-resolved optical spectroscopy has been employed for mechanistic studies in model systems designed to undergo photo-induced proton-coupled electron transfer (PCET) and oxygen atom transfer (OAT) reactions, both of which ...
Harvesting nanoscale thermal radiation using pyroelectric materials
Fang, Jin; Frederich, Hugo; Pilon, Laurent
2010-01-01T23:59:59.000Z
eld radiative heat transfer dominates radiation transferstudy Far field radiation Heat transfer coefficient, h r (W/nanoscale radiation to enhance radiative heat transfer. The
Radiative heat transfer between two dielectric nanogratings in the scattering approach
J. Lussange; R. Guérout; F. S. S. Rosa; J. -J. Greffet; A. Lambrecht; S. Reynaud
2012-06-01T23:59:59.000Z
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.
Alan M. Watson; William J. Henney
2001-08-30T23:59:59.000Z
We describe an efficient Monte Carlo algorithm for a restricted class of scattering problems in radiation transfer. This class includes many astrophysically interesting problems, including the scattering of ultraviolet and visible light by grains. The algorithm correctly accounts for multiply-scattered light. We describe the algorithm, present a number of important optimizations, and explicity show how the algorithm can be used to estimate quantities such as the emergent and mean intensity. We present two test cases, examine the importance of the optimizations, and show that this algorithm can be usefully applied to optically-thin problems, a regime sometimes considered limited to explicit single-scattering plus attenuation approximations.
Grossmann, Ignacio E.
Heat transfer model of large shipping containers 1Chemical Engineering Department - Carnegie Mellon to the inside air 3. Heat transfer at the cargo on the pallets I. The heat transfer model Outline: II. Case
Frequency-Selective Near-Field Radiative Heat Transfer between Photonic Crystal Slabs-selective near-field radiative heat transfer between patterned (photonic-crystal) slabs at designable frequencies and separations, exploiting a general numerical approach for computing heat transfer in arbitrary geometries
Tominaga, Nozomu; Blinnikov, Sergei I
2015-01-01T23:59:59.000Z
We develop a time-dependent multi-group multidimensional relativistic radiative transfer code, which is required to numerically investigate radiation from relativistic fluids involved in, e.g., gamma-ray bursts and active galactic nuclei. The code is based on the spherical harmonic discrete ordinate method (SHDOM) that evaluates a source function including anisotropic scattering in spherical harmonics and implicitly solves the static radiative transfer equation with a ray tracing in discrete ordinates. We implement treatments of time dependence, multi-frequency bins, Lorentz transformation, and elastic Thomson and inelastic Compton scattering to the publicly available SHDOM code. Our code adopts a mixed frame approach; the source function is evaluated in the comoving frame whereas the radiative transfer equation is solved in the laboratory frame. This implementation is validated with various test problems and comparisons with results of a relativistic Monte Carlo code. These validations confirm that the code ...
Higginbottom, Nick; Knigge, Christian; Matthews, James H. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Proga, Daniel [Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154-4002 (United States); Long, Knox S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Sim, Stuart A., E-mail: nick_higginbottom@fastmail.fm [School of Mathematics and Physics, Queens University Belfast, University Road, Belfast, BT7 1NN (United Kingdom)
2014-07-01T23:59:59.000Z
Accretion disk winds are thought to produce many of the characteristic features seen in the spectra of active galactic nuclei (AGNs) and quasi-stellar objects (QSOs). These outflows also represent a natural form of feedback between the central supermassive black hole and its host galaxy. The mechanism for driving this mass loss remains unknown, although radiation pressure mediated by spectral lines is a leading candidate. Here, we calculate the ionization state of, and emergent spectra for, the hydrodynamic simulation of a line-driven disk wind previously presented by Proga and Kallman. To achieve this, we carry out a comprehensive Monte Carlo simulation of the radiative transfer through, and energy exchange within, the predicted outflow. We find that the wind is much more ionized than originally estimated. This is in part because it is much more difficult to shield any wind regions effectively when the outflow itself is allowed to reprocess and redirect ionizing photons. As a result, the calculated spectrum that would be observed from this particular outflow solution would not contain the ultraviolet spectral lines that are observed in many AGN/QSOs. Furthermore, the wind is so highly ionized that line driving would not actually be efficient. This does not necessarily mean that line-driven winds are not viable. However, our work does illustrate that in order to arrive at a self-consistent model of line-driven disk winds in AGN/QSO, it will be critical to include a more detailed treatment of radiative transfer and ionization in the next generation of hydrodynamic simulations.
RADIATION HEAT TRANSFER ENVIRONMENT IN FIRE AND FURNACE TESTS OF RADIOACTIVE MATERIALS PAKCAGES
Smith, A
2008-12-31T23:59:59.000Z
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.
Heat transfer model of above and underground insulated piping systems
Kwon, K.C.
1998-07-01T23:59:59.000Z
A simplified heat transfer model of above and underground insulated piping systems was developed to perform iterative calculations for fluid temperatures along the entire pipe length. It is applicable to gas, liquid, fluid flow with no phase change. Spreadsheet computer programs of the model have been developed and used extensively to perform the above calculations for thermal resistance, heat loss and core fluid temperature.
Paris-Sud XI, Université de
Analysis of roll gap heat transfers in hot steel strip rolling through roll temperature sensors and heat transfer models N. Legrand1,a , N. Labbe1,b D. Weisz-Patrault2,c , A. Ehrlacher2,d , T. Luks3,e heat transfers during pilot hot steel strip rolling. Two types of temperature sensors (drilled and slot
Modelling of heat transfer and crystallation kinetics in thermoplastic pultrusion
Carlsson, A.; Astroem, B.T. [Royal Institute of Technology, Stockholm (Sweden)
1996-12-31T23:59:59.000Z
While pultrusion with thermoset resins has been widely analyses, there is a scarcity of knowledge about pultrusion with thermoplastic resins. The objective of the present study is to develop a realistic heat transfer model for the entire thermoplastic pultrusion process, from room temperature prepreg, through preheater and dies, to room temperature composite. The aim is to determine dominating heat transfer mechanisms and to be able to predict residual stresses and crystallinity, which depend on the thermal history of the composite. A complete heat transfer model including crystallization kinetics is presented. Results show reasonably good agreement with experimental data and the model thus provides a tool for process simulations with a variety of processing parameters.
A BAYESIAN MODEL COMMITTEE APPROACH TO FORECASTING GLOBAL SOLAR RADIATION
Boyer, Edmond
1 A BAYESIAN MODEL COMMITTEE APPROACH TO FORECASTING GLOBAL SOLAR RADIATION in the realm of solar radiation forecasting. In this work, two forecasting models: Autoregressive Moving. The very first results show an improvement brought by this approach. 1. INTRODUCTION Solar radiation
Modelling proton transfer in water molecule chains
Artem Korzhimanov; Mattias Marklund; Tatiana Shutova; Goran Samuelsson
2011-08-22T23:59:59.000Z
The process of protons transport in molecular water chains is of fundamental interest for many biological systems. Although many features of such systems can be analyzed using large-scale computational modeling, other features are better understood in terms of simplified model problems. Here we have tested, analytically and numerically, a model describing the classical proton hopping process in molecular water chains. In order to capture the main features of the proton hopping process in such molecular chains, we use a simplified model for our analysis. In particular, our discrete model describes a 1D chain of water molecules situated in an external protein channel structure, and each water molecule is allowed to oscillate around its equilibrium point in this system, while the protons are allowed to move along the line of neighboring oxygen atoms. The occurrence and properties of nonlinear solitary transport structures, allowing for much faster proton transport, are discussed, and the possible implications of these findings for biological systems are emphasized.
Radiative charge transfer in cold and ultracold Sulfur atoms colliding with Protons
G Shen; P C Stancil; J G Wang; J F McCann; B M McLaughlin
2015-02-25T23:59:59.000Z
Radiative decay processes at cold and ultra cold temperatures for Sulfur atoms colliding with protons are investigated. The MOLPRO quantum chemistry suite of codes was used to obtain accurate potential energies and transition dipole moments, as a function of internuclear distance, between low-lying states of the SH$^{+}$ molecular cation. A multi-reference configuration-interaction (MRCI) approximation together with the Davidson correction is used to determine the potential energy curves and transition dipole moments, between the states of interest, where the molecular orbitals (MO's) are obtained from state-averaged multi configuration-self-consistent field (MCSCF) calculations. The collision problem is solved approximately using an optical potential method to obtain radiative loss, and a fully two-channel quantum approach for radiative charge transfer. Cross sections and rate coefficients are determined for the first time for temperatures ranging from 10 $\\mu$ K up to 10,000 K. Results are obtained for all isotopes of Sulfur, colliding with H$^{+}$ and D$^{+}$ ions and comparison is made to a number of other collision systems.
An adaptive radiation model for the origin of new gene functions
Francino, M. Pilar
2005-01-01T23:59:59.000Z
An adaptive radiation model for the origin of new genePreadaptation Adaptive radiation Competition among closefor a specific niche Adaptive radiation model Adaptive gene
Minimum entropy production closure of the photo-hydrodynamic equations for radiative heat transfer
Thomas Christen; Frank Kassubek
2008-12-17T23:59:59.000Z
In the framework of a two-moment photo-hydrodynamic modelling of radiation transport, we introduce a concept for the determination of effective radiation transport coefficients based on the minimization of the local entropy production rate of radiation and matter. The method provides the nonequilibrium photon distribution from which the effective absorption coefficients and the variable Eddington factor (VEF) can be calculated. The photon distribution depends on the frequency dependence of the absorption coefficient, in contrast to the distribution obtained by methods based on entropy maximization. The calculated mean absorption coefficients are not only correct in the limit of optically thick and thin media, but even provide a reasonable interpolation in the cross-over regime between these limits, notably without introducing any fit parameter. The method is illustrated and discussed for grey matter and for a simple example of non-grey matter with a two-band absorption spectrum. The method is also briefly compared with the maximum entropy concept.
Efficiency transfer for regression models with responses missing at random
Mueller, Uschi
Efficiency transfer for regression models with responses missing at random Ursula U. M that characteristics of the con- ditional distribution of Y given X can be estimated efficiently using complete case analysis. One can simply omit incomplete cases and work with an appro- priate efficient estimator without
Quantum Black Hole Model and Hawking's Radiation
V. A. Berezin
1996-02-12T23:59:59.000Z
The black hole model with a self-gravitating charged spherical symmetric dust thin shell as a source is considered. The Schroedinger-type equation for such a model is derived. This equation appeared to be a finite differences equation. A theory of such an equation is developed and general solution is found and investigated in details. The discrete spectrum of the bound state energy levels is obtained. All the eigenvalues appeared to be infinitely degenerate. The ground state wave functions are evaluated explicitly. The quantum black hole states are selected and investigated. It is shown that the obtained black hole mass spectrum is compatible with the existence of Hawking's radiation in the limit of low temperatures both for large and nearly extreme Reissner-Nordstrom black holes. The above mentioned infinite degeneracy of the mass (energy) eigenvalues may appeared helpful in resolving the well known information paradox in the black hole physics.
Ellingson, R.G.; Baer, F.
1998-09-01T23:59:59.000Z
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.
Mass and heat transfer model of Tubular Solar Still
Ahsan, Amimul [University Putra Malaysia, Dept. Civil Engineering, Faculty of Engineering, 43400 UPM Serdang, Selangor (Malaysia); Fukuhara, Teruyuki [University of Fukui, Graduate School of Engineering, 3-9-1 Bunkyo, Fukui 910-8507 (Japan)
2010-07-15T23:59:59.000Z
In this paper, a new mass and heat transfer model of a Tubular Solar Still (TSS) was proposed incorporating various mass and heat transfer coefficients taking account of the humid air properties inside the still. The heat balance of the humid air and the mass balance of the water vapor in the humid air were formulized for the first time. As a result, the proposed model enabled to calculate the diurnal variations of the temperature, water vapor density and relative humidity of the humid air, and to predict the hourly condensation flux besides the temperatures of the water, cover and trough, and the hourly evaporation flux. The validity of the proposed model was verified using the field experimental results carried out in Fukui, Japan and Muscat, Oman in 2008. The diurnal variations of the calculated temperatures and water vapor densities had a good agreement with the observed ones. Furthermore, the proposed model can predict the daily and hourly production flux precisely. (author)
Forming chondrules in impact splashes. I. Radiative cooling model
Dullemond, Cornelis Petrus; Johansen, Anders
2015-01-01T23:59:59.000Z
The formation of chondrules is one of the oldest unsolved mysteries in meteoritics and planet formation. Recently an old idea has been revived: the idea that chondrules form as a result of collisions between planetesimals in which the ejected molten material forms small droplets which solidify to become chondrules. Pre-melting of the planetesimals by radioactive decay of 26Al would help producing sprays of melt even at relatively low impact velocity. In this paper we study the radiative cooling of a ballistically expanding spherical cloud of chondrule droplets ejected from the impact site. We present results from a numerical radiative transfer models as well as analytic approximate solutions. We find that the temperature after the start of the expansion of the cloud remains constant for a time t_cool and then drops with time t approximately as T ~ T_0[(3/5)t/t_cool+ 2/5]^(-5/3) for t>t_cool. The time at which this temperature drop starts t_cool depends via an analytical formula on the mass of the cloud, the e...
Heat Transfer Modeling and Use of Distributed Temperature Measurements to Predict Rate
Hashmi, Gibran Mushtaq
2014-07-08T23:59:59.000Z
Heat transfer modeling is important in many fields of engineering. In petroleum engineering, heat transfer modeling has many applications. One such application that this study focused on is flow rate estimation. In this work, two different models...
Huang, Dong [Brookhaven National Laboratory (BNL), Upton, NY (United States); Liu, Yangang [Brookhaven National Laboratory (BNL), Upton, NY (United States). Environmental and Climate Sciences Dept.
2014-12-18T23:59:59.000Z
Subgrid-scale variability is one of the main reasons why parameterizations are needed in large-scale models. Although some parameterizations started to address the issue of subgrid variability by introducing a subgrid probability distribution function for relevant quantities, the spatial structure has been typically ignored and thus the subgrid-scale interactions cannot be accounted for physically. Here we present a new statistical-physics-like approach whereby the spatial autocorrelation function can be used to physically capture the net effects of subgrid cloud interaction with radiation. The new approach is able to faithfully reproduce the Monte Carlo 3D simulation results with several orders less computational cost, allowing for more realistic representation of cloud radiation interactions in large-scale models.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Huang, Dong; Liu, Yangang
2014-12-18T23:59:59.000Z
Subgrid-scale variability is one of the main reasons why parameterizations are needed in large-scale models. Although some parameterizations started to address the issue of subgrid variability by introducing a subgrid probability distribution function for relevant quantities, the spatial structure has been typically ignored and thus the subgrid-scale interactions cannot be accounted for physically. Here we present a new statistical-physics-like approach whereby the spatial autocorrelation function can be used to physically capture the net effects of subgrid cloud interaction with radiation. The new approach is able to faithfully reproduce the Monte Carlo 3D simulation results with several orders less computational cost,more »allowing for more realistic representation of cloud radiation interactions in large-scale models.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Huang, Dong [Brookhaven National Laboratory (BNL), Upton, NY (United States); Liu, Yangang [Brookhaven National Laboratory (BNL), Upton, NY (United States)
2014-12-01T23:59:59.000Z
Subgrid-scale variability is one of the main reasons why parameterizations are needed in large-scale models. Although some parameterizations started to address the issue of subgrid variability by introducing a subgrid probability distribution function for relevant quantities, the spatial structure has been typically ignored and thus the subgrid-scale interactions cannot be accounted for physically. Here we present a new statistical-physics-like approach whereby the spatial autocorrelation function can be used to physically capture the net effects of subgrid cloud interaction with radiation. The new approach is able to faithfully reproduce the Monte Carlo 3D simulation results with several orders less computational cost, allowing for more realistic representation of cloud radiation interactions in large-scale models.
Jiri Stepan; Petr Heinzel; Sylvie Sahal-Brechot
2007-01-22T23:59:59.000Z
Context. We present a theoretical review of the effect of impact polarization of a hydrogen H$\\alpha$ line due to an expected proton beam bombardment in solar flares. Aims. Several observations indicate the presence of the linear polarization of the hydrogen H$\\alpha$ line observed near the solar limb above 5% and preferentially in the radial direction. We theoretically review the problem of deceleration of the beam originating in the coronal reconnection site due to its interaction with the chromospheric plasma, and describe the formalism of the density matrix used in our description of the atomic processes and the treatment of collisional rates. Methods. We solve the self-consistent NLTE radiation transfer problem for the particular semiempirical chromosphere models for both intensity and linear polarization components of the radiation field. Results. In contrast to recent calculations, our results show that the energy distribution of the proton beam at H$\\alpha$ formation levels and depolarizing collisions by background electrons and protons cause a significant reduction of the effect below 0.1%. The radiation transfer solution shows that tangential resonance-scattering polarization dominates over the impact polarization effect in all considered models. Conclusions. In the models studied, proton beams are unlikely to be a satisfying explanation for the observed linear polarization of the H$\\alpha$ line.
Heat transfer modeling of dry spent nuclear fuel storage facilities
Lee, S.Y.
1999-07-01T23:59:59.000Z
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 geologic codisposal Waste Package (WP). Calculated temperatures will be used to demonstrate engineering viability of a dry storage option in enclosed interim storage and geologic 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.
Heat Transfer Modeling of Dry Spent Nuclear Fuel Storage Facilities
Lee, S.Y.
1999-01-13T23:59:59.000Z
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.
Simulation of adsorption of uranium from seawater using liquid film mass transfer controlling model
Omichi, H.; Kataki, A.; Okamoto, J.
1988-08-01T23:59:59.000Z
A liquid film mass transfer control model was applied to the batch adsorption of uranium from seawater with an amidoxime-group-containing polymeric adsorbent made by the radiation-induced grafting method. The adsorption amount was calculated by changing two parameters, equilibrium adsorption amount q/sub 0/ and liquid film mass transfer coefficient k, to obtain the best fit between the observed and calculate values. The index of a Freundlich-type isotherm was obtained as 1.6, which is similar to the previously observed value with hydrous titanium oxide adsorbent. The plot k vs 1/T provided the activation energy as 10.0 kcal/mol. Both q/sub 0/ and k showed an approximately first-order dependency on the amidoxime group content in the adsorbent. The simulation made it clear that the increase in k brought about by mixing amidoxime groups with carboxyl groups was due to a synergistic effect of these groups.
Wave radiation in simple geophysical models
Murray, Stuart William
2013-07-01T23:59:59.000Z
Wave radiation is an important process in many geophysical flows. In particular, it is by wave radiation that flows may adjust to a state for which the dynamics is slow. Such a state is described as “balanced”, meaning ...
Baes, Maarten
2008-01-01T23:59:59.000Z
that is inherent in Monte Carlo radiative transfer simulations. As the typical detectors used in Monte Carlo negligible, we recommend the use of smart detectors in Monte Carlo radiative transfer simulations. Key wordsMon. Not. R. Astron. Soc. 391, 617623 (2008) doi:10.1111/j.1365-2966.2008.13941.x Smart detectors
Yang, Yue
2015-01-01T23:59:59.000Z
In the present work, we theoretically demonstrate, for the first time, that near field radiative transport between 1D periodic grating microstructures separated by subwavelength vacuum gaps can be significantly enhanced by exciting magnetic resonance or polariton. Fluctuational electrodynamics that incorporates scattering matrix theory with rigorous coupled wave analysis is employed to exactly calculate the near field radiative heat flux between two SiC gratings. Besides the well known coupled surface phonon polaritons (SPhP), an additional spectral radiative heat flux peak, which is due to magnetic polariton, is found within the phonon absorption band of SiC. The mechanisms, behaviors and interplays between magnetic polariton, coupled SPhP, single interface SPhP, and Wood's anomaly in the near field radiative transport are elucidated in detail. The findings will open up a new way to control near field radiative heat transfer by magnetic resonance with micro or nanostructured metamaterials.
RELAP5 MODEL OF THE DIVERTOR PRIMARY HEAT TRANSFER SYSTEM
Popov, Emilian L [ORNL; Yoder Jr, Graydon L [ORNL; Kim, Seokho H [ORNL
2010-08-01T23:59:59.000Z
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.
Improvements to the SHDOM Radiative Transfer Modeling Package
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville PowerTariff Pages default Sign In About | CareersUSING PVImpactInnovationImprovements to MARFA
CROSS VALIDATION OF SATELLITE RADIATION TRANSFER MODELS DURING SWERA PROJECT
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh4-FD-aBeijing SinohytecBrownville, Maine:Butte,CEPIS Jump to:CO2 CaptureCPower (Texas)
Higgs inflation in a radiative seesaw model
Shinya Kanemura; Toshinori Matsui; Takehiro Nabeshima
2013-04-13T23:59:59.000Z
We investigate a simple model to explain inflation, neutrino masses and dark matter simultaneously. This is based on the so-called radiative seesaw model proposed by Ma in order to explain neutrino masses and dark matter by introducing a $Z_2$-odd isospin doublet scalar field and $Z_2$-odd right-handed neutrinos. We study the possibility that the Higgs boson as well as neutral components of the $Z_2$-odd scalar doublet field can satisfy conditions from slow-roll inflation and vacuum stability up to the inflation scale. We find that a part of parameter regions where these scalar fields can play a role of an inflaton is compatible with the current data from neutrino experiments and those of the dark matter abundance as well as the direct search results. A phenomenological consequence of this scenario results in a specific mass spectrum of scalar bosons, which can be tested at the LHC, the International Linear Collider and the Compact Linear Collider.
Modeling of fuel-to-steel heat transfer in core disruptive accidents
Smith, Russell Charles
1980-01-01T23:59:59.000Z
A mathematical model for direct-contact boiling heat transfer between immiscible fluids was developed and tested experimentally. The model describes heat transfer from a hot fluid bath to an ensemble of droplets of a cooler ...
Fluid flow and heat transfer modeling for castings
Domanus, H.M.; Liu, Y.Y.; Sha, W.T.
1986-01-01T23:59:59.000Z
Casting is fundamental to manufacturing of many types of equipment and products. Although casting is a very old technology that has been in existence for hundreds of years, it remains a highly empirical technology, and production of new castings requires an expensive and time-consuming trial-and-error approach. In recent years, mathematical modeling of casting has received increasing attention; however, a majority of the modeling work has been in the area of heat transfer and solidification. Very little work has been done in modeling fluid flow of the liquid melt. This paper presents a model of fluid flow coupled with heat transfer of a liquid melt for casting processes. The model to be described in this paper is an extension of the COMMIX code and is capable of handling castings with any shape, size, and material. A feature of this model is the ability to track the liquid/gas interface and liquid/solid interface. The flow of liquid melt through the sprue and runners and into the mold cavity is calculated as well as three-dimensional temperature and velocity distributions of the liquid melt throughout the casting process. 14 refs., 13 figs.
MODELING OF HEAT TRANSFER IN ROOMS IN THE MODELICA "BUILDINGS" LIBRARY
describes the implementation of the room heat transfer model in the free open-source Modelica "Buildings
A meshless method for modeling convective heat transfer
Carrington, David B [Los Alamos National Laboratory
2010-01-01T23:59:59.000Z
A meshless method is used in a projection-based approach to solve the primitive equations for fluid flow with heat transfer. The method is easy to implement in a MATLAB format. Radial basis functions are used to solve two benchmark test cases: natural convection in a square enclosure and flow with forced convection over a backward facing step. The results are compared with two popular and widely used commercial codes: COMSOL, a finite element model, and FLUENT, a finite volume-based model.
Modelling charge transfer reactions with the frozen density embedding formalism
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
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.
Ly{alpha} RADIATIVE TRANSFER IN COSMOLOGICAL SIMULATIONS USING ADAPTIVE MESH REFINEMENT
Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen Oe (Denmark); Razoumov, Alexei O. [Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary's University, Halifax, NS, B3H3C3 (Canada); Sommer-Larsen, Jesper [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstrasse 2, D-85748 Garching (Germany)], E-mail: pela@dark-cosmology.dk, E-mail: razoumov@ap.smu.ca, E-mail: jslarsen@astro.ku.dk
2009-05-01T23:59:59.000Z
A numerical code for solving various Ly{alpha} radiative transfer (RT) problems is presented. The code is suitable for an arbitrary, three-dimensional distribution of Ly{alpha} emissivity, gas temperature, density, and velocity field. Capable of handling Ly{alpha} RT in an adaptively refined grid-based structure, it enables detailed investigation of the effects of clumpiness of the interstellar (or intergalactic) medium. The code is tested against various geometrically and physically idealized configurations for which analytical solutions exist, and subsequently applied to three different simulated high-resolution 'Lyman-break galaxies', extracted from high-resolution cosmological simulations at redshift z = 3.6. Proper treatment of the Ly{alpha} scattering reveals a diversity of surface brightness (SB) and line profiles. Specifically, for a given galaxy the maximum observed SB can vary by an order of magnitude, and the total flux by a factor of 3-6, depending on the viewing angle. This may provide an explanation for differences in observed properties of high-redshift galaxies, and in particular a possible physical link between Lyman-break galaxies and regular Ly{alpha} emitters.
Chen, Du; Bogy, David B.
2010-01-01T23:59:59.000Z
Bogy, D.B. : A heat transfer model for thermal ?uctuation inA phenomenological heat transfer model for the molecular gasA generalized heat transfer model for thin ?lm bearings at
Gritzo, L.A.; Skocypec, R.D. [Sandia National Labs., Albuquerque, NM (United States); Tong, T.W. [Arizona State Univ., Tempe, AZ (United States). Dept. of Mechanical and Aerospace Engineering
1995-01-11T23:59:59.000Z
Radiation in participating media is an important transport mechanism in many physical systems. The simulation of complex radiative transfer has not effectively exploited high-performance computing capabilities. In response to this need, a workshop attended by members active in the high-performance computing community, members active in the radiative transfer community, and members from closely related fields was held to identify how high-performance computing can be used effectively to solve the transport equation and advance the state-of-the-art in simulating radiative heat transfer. This workshop was held on March 29-30, 1994 in Albuquerque, New Mexico and was conducted by Sandia National Laboratories. The objectives of this workshop were to provide a vehicle to stimulate interest and new research directions within the two communities to exploit the advantages of high-performance computing for solving complex radiative heat transfer problems that are otherwise intractable.
Kravis, S. D.; Church, David A.; Johnson, B. M.; Meron, M.; Jones, K. W.; Levin, J. C.; Sellin, I. A.; Azuma, Y.; Berrahmansour, N.; Berry, H. G.; Druetta, M.
1992-01-01T23:59:59.000Z
PHYSICAL REVIEW A VOLUME 45, NUMBER 9 1 MAY 1992 Electron transfer from H2 and Ar to stored multiply charged argon ions produced by synchrotron radiation S. D. Kravis* and D. A. Church Physics Department, Texas A &M University, College Station... Ridge National Laboratory, Oak Ridge, Tennessee 37831 Y. Azuma, N. Berrah-Mansour, and H. G. Berry Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 M. Druetta Laboratoire Traitement du Signal et Instrumentation, Universite de St...
Moncada-Villa, Edwin; Garcia-Vidal, Francisco J; Garcia-Martin, Antonio; Cuevas, Juan Carlos
2015-01-01T23:59:59.000Z
We present a comprehensive theoretical study of the magnetic field dependence of the near-field radiative heat transfer (NFRHT) between two parallel plates. We show that when the plates are made of doped semiconductors, the near-field thermal radiation can be severely affected by the application of a static magnetic field. We find that irrespective of its direction, the presence of a magnetic field reduces the radiative heat conductance, and dramatic reductions up to 700% can be found with fields of about 6 T at room temperature. We show that this striking behavior is due to the fact that the magnetic field radically changes the nature of the NFRHT. The field not only affects the electromagnetic surface waves (both plasmons and phonon polaritons) that normally dominate the near-field radiation in doped semiconductors, but it also induces hyperbolic modes that progressively dominate the heat transfer as the field increases. In particular, we show that when the field is perpendicular to the plates, the semicond...
Siewert, Charles E.
-grey heat transfer model is that of SIMMONS and FERZIGER(~)who used the normal modes(4) of the equation
TRANSIENT HEAT TRANSFER MODEL FOR SRS WASTE TANK OPERATIONS
Lee, S; Richard Dimenna, R
2007-03-27T23:59:59.000Z
A transient heat balance model was developed to assess the impact of a Submersible Mixer Pump (SMP) on waste temperature during the process of waste mixing and removal for the Type-I Savannah River Site (SRS) tanks. The model results will be mainly used to determine the SMP design impacts on the waste tank temperature during operations and to develop a specification for a new SMP design to replace existing long-shaft mixer pumps used during waste removal. The model will also be used to provide input to the operation planning. This planning will be used as input to pump run duration in order to maintain temperature requirements within the tank during SMP operation. The analysis model took a parametric approach. A series of the modeling analyses was performed to examine how submersible mixer pumps affect tank temperature during waste removal operation in the Type-I tank. The model domain included radioactive decay heat load, two SMP's, and one Submersible Transfer Pump (STP) as heat source terms. The present model was benchmarked against the test data obtained by the tank measurement to examine the quantitative thermal response of the tank and to establish the reference conditions of the operating variables under no SMP operation. The results showed that the model predictions agreed with the test data of the waste temperatures within about 10%. Transient modeling calculations for two potential scenarios of sludge mixing and removal operations have been made to estimate transient waste temperatures within a Type-I waste tank. When two 200-HP submersible mixers and 12 active cooling coils are continuously operated in 100-in tank level and 40 C initial temperature for 40 days since the initiation of mixing operation, waste temperature rises about 9 C in 48 hours at a maximum. Sensitivity studies for the key operating variables were performed. The sensitivity results showed that the chromate cooling coil system provided the primary cooling mechanism to remove process heat from the tank during operation.
Modelling the Transfer Function for the Dark Energy Survey
Chang, C.
2014-10-31T23:59:59.000Z
We present a forward-modelling simulation framework designed to model the data products from the Dark Energy Survey (DES). This forward-model process can be thought of as a transfer function -- a mapping from cosmological and astronomical signals to the final data products used by the scientists. Using output from the cosmological simulations (the Blind Cosmology Challenge), we generate simulated images (the Ultra Fast Image Simulator, Berge et al. 2013) and catalogs representative of the DES data. In this work we simulate the 244 sq. deg coadd images and catalogs in 5 bands for the DES Science Verification (SV) data. The simulation output is compared with the corresponding data to show that major characteristics of the images and catalogs can be captured. We also point out several directions of future improvements. Two practical examples, star/galaxy classification and proximity effects on object detection, are then used to demonstrate how one can use the simulations to address systematics issues in data analysis. With clear understanding of the simplifications in our model, we show that one can use the simulations side-by-side with data products to interpret the measurements. This forward modelling approach is generally applicable for other upcoming and future surveys. It provides a powerful tool for systematics studies which is sufficiently realistic and highly controllable.
Modeling the Transfer Function for the Dark Energy Survey
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Chang, C.; Busha, M. T.; Wechsler, R. H.; Refregier, A.; Amara, A.; Rykoff, E.; Becker, M. R.; Bruderer, C.; Gamper, L.; Leistedt, B.; et al
2015-03-10T23:59:59.000Z
We present a forward-modelling simulation framework designed to model the data products from the Dark Energy Survey (DES). This forward-model process can be thought of as a transfer function -- a mapping from cosmological and astronomical signals to the final data products used by the scientists. Using output from the cosmological simulations (the Blind Cosmology Challenge), we generate simulated images (the Ultra Fast Image Simulator, Berge et al. 2013) and catalogs representative of the DES data. In this work we simulate the 244 deg2 coadd images and catalogs in 5 bands for the DES Science Verification (SV) data. The simulationmore »output is compared with the corresponding data to show that major characteristics of the images and catalogs can be captured. We also point out several directions of future improvements. Two practical examples, star/galaxy classification and proximity effects on object detection, are then used to demonstrate how one can use the simulations to address systematics issues in data analysis. With clear understanding of the simplifications in our model, we show that one can use the simulations side-by-side with data products to interpret the measurements. This forward modelling approach is generally applicable for other upcoming and future surveys. It provides a powerful tool for systematics studies which is sufficiently realistic and highly controllable.« less
Modeling the Transfer Function for the Dark Energy Survey
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Chang, C.; Busha, M. T.; Wechsler, R. H.; Refregier, A.; Amara, A.; Rykoff, E.; Becker, M. R.; Bruderer, C.; Gamper, L.; Leistedt, B.; Peiris, H.; Abbott, T.; Abdalla, F. B.; Balbinot, E.; Banerji, M.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Carnero, A.; Desai, S.; da Costa, L. N.; Cunha, C. E; Eifler, T.; Evrard, A. E.; Fausti Neto, A.; Gerdes, D.; Gruen, D.; James, D.; Kuehn, K.; Maia, M. A. G.; Makler, M.; Ogando, R.; Plazas, A.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, C.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Zuntz, J.
2015-03-10T23:59:59.000Z
We present a forward-modelling simulation framework designed to model the data products from the Dark Energy Survey (DES). This forward-model process can be thought of as a transfer function -- a mapping from cosmological and astronomical signals to the final data products used by the scientists. Using output from the cosmological simulations (the Blind Cosmology Challenge), we generate simulated images (the Ultra Fast Image Simulator, Berge et al. 2013) and catalogs representative of the DES data. In this work we simulate the 244 deg2 coadd images and catalogs in 5 bands for the DES Science Verification (SV) data. The simulation output is compared with the corresponding data to show that major characteristics of the images and catalogs can be captured. We also point out several directions of future improvements. Two practical examples, star/galaxy classification and proximity effects on object detection, are then used to demonstrate how one can use the simulations to address systematics issues in data analysis. With clear understanding of the simplifications in our model, we show that one can use the simulations side-by-side with data products to interpret the measurements. This forward modelling approach is generally applicable for other upcoming and future surveys. It provides a powerful tool for systematics studies which is sufficiently realistic and highly controllable.
Development of Aerosol Models for Radiative Flux Calculations at ARM Sites
Ogren, John A.; Dutton, Ellsworth G.; McComiskey, Allison C.
2006-09-30T23:59:59.000Z
The direct radiative forcing (DRF) of aerosols, the change in net radiative flux due to aerosols in non-cloudy conditions, is an essential quantity for understanding the human impact on climate change. Our work has addressed several key issues that determine the accuracy, and identify the uncertainty, with which aerosol DRF can be modeled. These issues include the accuracy of several radiative transfer models when compared to measurements and to each other in a highly controlled closure study using data from the ARM 2003 Aerosol IOP. The primary focus of our work has been to determine an accurate approach to assigning aerosol properties appropriate for modeling over averaged periods of time and space that represent the observed regional variability of these properties. We have also undertaken a comprehensive analysis of the aerosol properties that contribute most to uncertainty in modeling aerosol DRF, and under what conditions they contribute the most uncertainty. Quantification of these issues enables the community to better state accuracies of radiative forcing calculations and to concentrate efforts in areas that will decrease uncertainties in these calculations in the future.
Testing a model of IR radiative losses Frank Vignola
Oregon, University of
Testing a model of IR radiative losses Frank Vignola University of Oregon Department of Physics (SRRL) at the National Renewable Energy Laboratory are used to test and further develop a model and tested to adjust the non-pyrgeometer based correlation models to sites with different sky temperature
Canopy radiation transmission for an energy balance snowmelt model
Tarboton, David
Canopy radiation transmission for an energy balance snowmelt model Vinod Mahat1 and David G deep canopy solution. This solution enhances capability for modeling energy balance processes in a distributed energy balance snowmelt model and results compared with observations made in three different
Modeling Momentum Transfer from Kinetic Impacts: Implications for Redirecting Asteroids
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Stickle, A. M.; Atchison, J. A.; Barnouin, O. S.; Cheng, A. F.; Crawford, D. A.; Ernst, C. M.; Fletcher, Z.; Rivkin, A. S.
2015-05-19T23:59:59.000Z
Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ~300-kg spacecraft designed to impact the moon of the binary system 65803 Didymos. The deflection of the moon will be measured by the ESA-led Asteroid Impact Mission (AIM) (which will characterize the moon) and from ground-based observations. Because the material properties and internal structure ofmore »the target are poorly constrained, however, analytical models and numerical simulations must be used to understand the range of potential outcomes. Here, we describe a modeling effort combining analytical models and CTH simulations to determine possible outcomes of the DART impact. We examine a wide parameter space and provide predictions for crater size, ejecta mass, and momentum transfer following the impact into the moon of the Didymos system. For impacts into “realistic” asteroid types, these models produce craters with diameters on the order of 10 m, an imparted ?v of 0.5–2 mm/s and a momentum enhancement of 1.07 to 5 for a highly porous aggregate to a fully dense rock.« less
Robert G. Ellingson
2004-09-28T23:59:59.000Z
One specific goal of the Atmospheric Radiation Measurements (ARM) program is to improve the treatment of radiative transfer in General Circulation Models (GCMs) under clear-sky, general overcast and broken cloud conditions. Our project was geared to contribute to this goal by attacking major problems associated with one of the dominant radiation components of the problem --longwave radiation. The primary long-term project objectives were to: (1) develop an optimum longwave radiation model for use in GCMs that has been calibrated with state-of-the-art observations for clear and cloudy conditions, and (2) determine how the longwave radiative forcing with an improved algorithm contributes relatively in a GCM when compared to shortwave radiative forcing, sensible heating, thermal advection and convection. The approach has been to build upon existing models in an iterative, predictive fashion. We focused on comparing calculations from a set of models with operationally observed data for clear, overcast and broken cloud conditions. The differences found through the comparisons and physical insights have been used to develop new models, most of which have been tested with new data. Our initial GCM studies used existing GCMs to study the climate model-radiation sensitivity problem. Although this portion of our initial plans was curtailed midway through the project, we anticipate that the eventual outcome of this approach will provide both a better longwave radiative forcing algorithm and from our better understanding of how longwave radiative forcing influences the model equilibrium climate, how improvements in climate prediction using this algorithm can be achieved.
Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow
Boyer, Edmond
Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow S in a rotor-stator cavity subjected to a superimposed throughflow with heat transfer. Nu- merical predictions field from the heat transfer process. The turbulent flux is approximated by a gradient hypothesis
Validation of nuclear models used in space radiation shielding applications
Norman, Ryan B., E-mail: Ryan.B.Norman@nasa.gov [NASA Langley Research Center, Hampton, VA 23681 (United States); Blattnig, Steve R. [NASA Langley Research Center, Hampton, VA 23681 (United States)] [NASA Langley Research Center, Hampton, VA 23681 (United States)
2013-01-15T23:59:59.000Z
A program of verification and validation has been undertaken to assess the applicability of models to space radiation shielding applications and to track progress as these models are developed over time. In this work, simple validation metrics applicable to testing both model accuracy and consistency with experimental data are developed. The developed metrics treat experimental measurement uncertainty as an interval and are therefore applicable to cases in which epistemic uncertainty dominates the experimental data. To demonstrate the applicability of the metrics, nuclear physics models used by NASA for space radiation shielding applications are compared to an experimental database consisting of over 3600 experimental cross sections. A cumulative uncertainty metric is applied to the question of overall model accuracy, while a metric based on the median uncertainty is used to analyze the models from the perspective of model development by examining subsets of the model parameter space.
Intra-channel mass and heat-transfer modeling in diesel oxidation catalysts
Tennessee, University of
02FCC-140 Intra-channel mass and heat-transfer modeling in diesel oxidation catalysts Kalyana transfer in modeling the performance of diesel oxidation catalysts. Many modeling studies have assumed experimental measurements of CO and hydrocarbon oxidation in diesel exhaust re- veal that actual mass
Application Of A Spherical-Radial Heat Transfer Model To Calculate...
Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Jump to: navigation, search OpenEI Reference LibraryAdd to library...
Radiative and Auger decay data for modelling nickel K lines
P. Palmeri; P. Quinet; C. Mendoza; M. A. Bautista; J. Garcia; M. C. Witthoeft; T. R. Kallman
2008-06-06T23:59:59.000Z
Radiative and Auger decay data have been calculated for modelling the K lines in ions of the nickel isonuclear sequence, from Ni$^+$ up to Ni$^{27+}$. Level energies, transition wavelengths, radiative transition probabilities, and radiative and Auger widths have been determined using Cowan's Hartree--Fock with Relativistic corrections (HFR) method. Auger widths for the third-row ions (Ni$^+$--Ni$^{10+}$) have been computed using single-configuration average (SCA) compact formulae. Results are compared with data sets computed with the AUTOSTRUCTURE and MCDF atomic structure codes and with available experimental and theoretical values, mainly in highly ionized ions and in the solid state.
Paris-Sud XI, Université de
Ratkowsky "square root" model and a simplified two-parameter20 heat transfer model regarding an infinite
Liu, Hongyu
Radiative effect of clouds on tropospheric chemistry in a global three-dimensional chemical. (2006), Radiative effect of clouds on tropospheric chemistry in a global three-dimensional chemical frequencies are calculated using the Fast-J radiative transfer algorithm. The GEOS-3 global cloud optical
A model code for the radiative theta pinch
Lee, S., E-mail: leesing@optusnet.com.au [INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 Australia (Australia); Physics Department, University of Malaya, Kuala Lumpur (Malaysia); Saw, S. H. [INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 Australia (Australia); Lee, P. C. K. [Nanyang Technological University, National Institute of Education, Singapore 637616 (Singapore); Akel, M. [Department of Physics, Atomic Energy Commission, Damascus, P. O. Box 6091, Damascus (Syrian Arab Republic); Damideh, V. [INTI International University, 71800 Nilai (Malaysia); Khattak, N. A. D. [Department of Physics, Gomal University, Dera Ismail Khan (Pakistan); Mongkolnavin, R.; Paosawatyanyong, B. [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10140 (Thailand)
2014-07-15T23:59:59.000Z
A model for the theta pinch is presented with three modelled phases of radial inward shock phase, reflected shock phase, and a final pinch phase. The governing equations for the phases are derived incorporating thermodynamics and radiation and radiation-coupled dynamics in the pinch phase. A code is written incorporating correction for the effects of transit delay of small disturbing speeds and the effects of plasma self-absorption on the radiation. Two model parameters are incorporated into the model, the coupling coefficient f between the primary loop current and the induced plasma current and the mass swept up factor f{sub m}. These values are taken from experiments carried out in the Chulalongkorn theta pinch.
Camps, Peter; Bianchi, Simone; Lunttila, Tuomas; Pinte, Christophe; Natale, Giovanni; Juvela, Mika; Fischera, Joerg; Fitzgerald, Michael P; Gordon, Karl; Baes, Maarten; Steinacker, Juergen
2015-01-01T23:59:59.000Z
We define an appropriate problem for benchmarking dust emissivity calculations in the context of radiative transfer (RT) simulations, specifically including the emission from stochastically heated dust grains. Our aim is to provide a self-contained guide for implementors of such functionality, and to offer insights in the effects of the various approximations and heuristics implemented by the participating codes to accelerate the calculations. The benchmark problem definition includes the optical and calorimetric material properties, and the grain size distributions, for a typical astronomical dust mixture with silicate, graphite and PAH components; a series of analytically defined radiation fields to which the dust population is to be exposed; and instructions for the desired output. We process this problem using six RT codes participating in this benchmark effort, and compare the results to a reference solution computed with the publicly available dust emission code DustEM. The participating codes implement...
Measure of Diffusion Model Error for Thermal Radiation Transport
Kumar, Akansha
2013-04-19T23:59:59.000Z
cm2 sh keV c Speed of light 2:99 102 cmsh D Di usion coe cient ( 13 t ) cm F Radiation ux jkcm2 sh k Time iteration t Di erence between consecutive time steps shakes(sh) hi Size of spatial cell, i cm ! Direction of photon propagation ster... +1 0 dE Z 4 d !r ; E; ! ; t : (4.2) The term ! F ( !r ; t) is the \\ ux", given by ! J ( !r ; t) = Z +1 0 dE Z 4 d ! !r ; E; ! ; t : (4.3) The above equation of transfer for speci c intensity is equivalent...
Jha, Naresh, E-mail: naresh.jha@albertahealthservices.ca [University of Alberta, Cross Cancer Institute, Edmonton, Alberta (Canada)] [University of Alberta, Cross Cancer Institute, Edmonton, Alberta (Canada); Harris, Jonathan [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States)] [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Seikaly, Hadi [University of Alberta, Edmonton, Alberta (Canada)] [University of Alberta, Edmonton, Alberta (Canada); Jacobs, John R. [Wayne State University School of Medicine, Detroit, Michigan (United States)] [Wayne State University School of Medicine, Detroit, Michigan (United States); McEwan, A.J.B. [University of Alberta, Cross Cancer Institute, Edmonton, Alberta (Canada)] [University of Alberta, Cross Cancer Institute, Edmonton, Alberta (Canada); Robbins, K. Thomas [St. John's Hospital Cancer Institute, Springfield, Illinois (United States)] [St. John's Hospital Cancer Institute, Springfield, Illinois (United States); Grecula, John [Ohio State University Medical Center, Columbus, Ohio (United States)] [Ohio State University Medical Center, Columbus, Ohio (United States); Sharma, Anand K. [Medical University of South Carolina, Charleston, South Carolina (United States)] [Medical University of South Carolina, Charleston, South Carolina (United States); Ang, K. Kian [University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [University of Texas MD Anderson Cancer Center, Houston, Texas (United States)
2012-10-01T23:59:59.000Z
Purpose: We report the results of a phase II study to determine the reproducibility of a submandibular salivary gland transfer (SGT) surgical technique for prevention of radiation (XRT)-induced xerostomia in a multi-institutional setting and to assess severity of xerostomia. Methods and Materials: Eligible patients had surgery for primary, neck dissection, and SGT, followed by XRT, during which the transferred salivary gland was shielded. Intensity modulated radiation therapy, amifostine, and pilocarpine were not allowed, but postoperative chemotherapy was allowed. Each operation was reviewed by 2 reviewers and radiation by 1 reviewer. If 13 or more (of 43) were 'not per protocol,' then the technique would be considered not reproducible as per study design. The secondary endpoint was the rate of acute xerostomia, grade 2 or higher, and a rate of {<=}51% was acceptable. Results: Forty-four of the total 49 patients were analyzable: male (81.8%), oropharynx (63.6%), stage IV (61.4%), median age 56.5 years. SGT was 'per protocol' or within acceptable variation in 34 patients (77.3%) and XRT in 79.5%. Nine patients (20.9%) developed grade 2 acute xerostomia; 2 had grade 0-1 xerostomia (4.7%) but started on amifostine/pilocarpine. Treatment for these 11 patients (25.6%) was considered a failure for the xerostomia endpoint. Thirteen patients died; median follow-up for 31 surviving patients was 2.9 years. Two-year overall and disease-free survival rates were 76.4% and 71.7%, respectively. Conclusions: The technique of submandibular SGT is reproducible in a multicenter setting. Seventy-four percent of patients were prevented from XRT-induced acute xerostomia.
Forristall, R.
2003-10-01T23:59:59.000Z
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.
HEAT AND MOISTURE TRANSFER THROUGH CLOTHING
Voelker, Conrad; Hoffmann, Sabine; Kornadt, Oliver; Arens, Edward; Zhang, Hui; Huizenga, Charlie
2009-01-01T23:59:59.000Z
R. C. Eberhart (ed), Heat transfer in medicine and biology.between convective heat transfer and mass transferConvective and radiative heat transfer coefficients for
Heat and moisture transfer through clothing
Voelker, Conrad; Hoffmann, Sabine; Kornadt, Oliver; Arens, Edward; Zhang, Hui; Huizenga, Charlie
2009-01-01T23:59:59.000Z
R. C. Eberhart (ed), Heat transfer in medicine and biology.Convective and radiative heat transfer coefficients forbetween convective heat transfer and mass transfer
Clementel, Nicola; Kruip, Chael J H; Paardekooper, Jan-Pieter
2015-01-01T23:59:59.000Z
Spectral observations of the massive colliding wind binary Eta Carinae show phase-dependent variations, in intensity and velocity, of numerous helium emission and absorption lines throughout the entire 5.54-year orbit. Approaching periastron, the 3D structure of the wind-wind interaction region (WWIR) gets highly distorted due to the eccentric ($e \\sim 0.9$) binary orbit. The secondary star ($\\eta_{\\mathrm{B}}$) at these phases is located deep within the primary's dense wind photosphere. The combination of these effects is thought to be the cause of the particularly interesting features observed in the helium lines at periastron. We perform 3D radiative transfer simulations of $\\eta$ Car's interacting winds at periastron. Using the SimpleX radiative transfer algorithm, we post-process output from 3D smoothed particle hydrodynamic simulations of the inner 150 au of the $\\eta$ Car system for two different primary star mass-loss rates ($\\dot{M}_{\\eta_{\\mathrm{A}}}$). Using previous results from simulations at ap...
De Castro, Carlos Armando
2011-01-01T23:59:59.000Z
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.
Paris-Sud XI, Université de
specially designed within the framework of this research. A computational heat transfer model is constructed. The developed mean model constitutes the basis of the computational stochastic heat transfer model that has been to the experimental ones. Keywords: computational heat transfer modeling, uncertainties, probabilistic modeling
Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow
Boyer, Edmond
Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow S modeling of the turbulent flow in a rotor-stator cavity subjected to a superimposed throughflow with heat the dynamical effects from the heat transfer process. The fluid flow in an enclosed disk system with axial
Wu, Zhigang
Charge-transfer electrostatic model of compositional order in perovskite alloys Zhigang Wu transfer that is shown to account for the observed B-site ordering in Pb-based perovskite alloys. The model the long-range compositional order of both Pb- and Ba-based complex A(BB B )O3 perovskite alloys
Hammes-Schiffer, Sharon
Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions A general minimal model for proton-coupled electron transfer PCET reactions in solution is presented. This model consists of three coupled degrees of freedom that represent an electron, a proton, and a solvent
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
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)
Development of a UF{sub 6} cylinder transient heat transfer/stress analysis model
Williams, W.R. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)
1991-12-31T23:59:59.000Z
A heat transfer/stress analysis model is being developed to simulate the heating to a point of rupture of a cylinder containing UF{sub 6} when it is exposed to a fire. The assumptions underlying the heat transfer portion of the model, which has been the focus of work to date, will be discussed. A key aspect of this model is a lumped parameter approach to modeling heat transfer. Preliminary results and future efforts to develop an integrated thermal/stress model will be outlined.
An adaptive radiation model for the origin of new gene functions
Francino, M. Pilar
2004-01-01T23:59:59.000Z
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
Curve fitting methods for solar radiation data modeling
Karim, Samsul Ariffin Abdul, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my; Singh, Balbir Singh Mahinder, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my [Department of Fundamental and Applied Sciences, Faculty of Sciences and Information Technology, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)
2014-10-24T23:59:59.000Z
This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R{sup 2}. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.
Reinhard W. Schulte MODELING OF RADIATION ACTION
. The detector measures individual ionizations in low-pressure (~ 1 Torr) propane or any other gas corresponding, and one may use water vapor or more complex gas mixtures matching the atomic composition of DNA. As new. Such a theory is presented and discussed in this paper. 2. Concepts of Nanodosimetry A low-pressure gas model
Numerical modelling of current transfer in nonlinear anisotropic conductive media
Baranowski, Robert Paul
on the nature of current transport. The main motivation for this work was the desire for a better understanding of the conceptually difficult behaviour of current transport in superconducting bodies and examines current transfer quantitatively for a number...
PARALLEL COMPUTATIONS OF RADIATIVE HEAT TRANSFER USING THE DISCRETE ORDINATES METHOD
Utah, University of
of the important radiatively active species (CO2, H2O, soot) and temperature, which are calculated on the spatially increasingly tractable. Issues relating to the use of high-performance computing in participating media heat properties. First we summarize previous applications of spatial decomposition strategies to finite
Ko, Min Seok
2009-05-15T23:59:59.000Z
? =0.1, 0.2, and 0.4) and scattering albedo ( ?=0, 0.25, 0.5, 0.75 and 1). Variation of thermophysical properties with temperature was considered in this study. In this work consideration was given only to cooling. Effects of those radiative...
Pannala, S; D'Azevedo, E; Zacharia, T
2002-02-26T23:59:59.000Z
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.
FireStem2D A Two-Dimensional Heat Transfer Model for Simulating Tree Stem Injury in Fires
FireStem2D A Two-Dimensional Heat Transfer Model for Simulating Tree Stem Injury in Fires, et al. (2013) FireStem2D A Two-Dimensional Heat Transfer Model for Simulating Tree Stem Injury
Nawaz, Waqas
2014-04-25T23:59:59.000Z
on the role of evaporation and convection phenomena on the cryogenic pool temperature and its vaporization rate. Various models describing heat transfer by evaporation were compared. The models differ from each other in terms of mass transfer coefficient...
The radiative heat transfer between a rotating nanoparticle and a plane surface
Vahid Ameri; Mehdi Shafei Aporvari; Fardin Kheirandish
2015-06-03T23:59:59.000Z
Based on a microscopic approach, we propose a Lagrangian for the combined system of a rotating dielectric nanoparticle above a plane surface in the presence of electromagnetic vacuum fluctuations. In the framework of canonical quantization, the electromagnetic vacuum field is quantized in the presence of dielectric fields describing the nanoparticle and a semi-infinite dielectric with planar interface. The radiative heat power absorbed by the rotating nanoparticle is obtained and the result is in agreement with previous results when the the rotational frequency of the nanoparticle is zero or much smaller than the relaxation frequency of the dielectrics. The well known near field effect is reexamined and discussed in terms of the rotational frequency. The radiative heat power absorbed by the nanoparticle for well-known peak frequencies, is plotted in terms of the rotational frequency showing an interesting effect resembling a phase transition around a critical frequency, determined by the relaxation frequency of the dielectrics.
Semi-Analytic Solutions to the Radiative Transfer Equations via Heterogeneous Computing
Holladay, Daniel Alphin
2014-12-10T23:59:59.000Z
to compute reaction rates for many different thermonuclear processes such as inertial confinement fusion. There are several large scale computer codes such as xRage developed at Los Alamos National Laboratory (LANL), KULL developed at Lawrence Livermore Na... spherical radiation source with A = 0.75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 vii 1. INTRODUCTION If fusion energy is to be harnessed on earth, a thorough understanding of the regime called high energy density physics must...
Semi-Analytic Solutions to the Radiative Transfer Equations via Heterogeneous Computing
Holladay, Daniel Alphin
2014-12-10T23:59:59.000Z
to compute reaction rates for many different thermonuclear processes such as inertial confinement fusion. There are several large scale computer codes such as xRage developed at Los Alamos National Laboratory (LANL), KULL developed at Lawrence Livermore Na... spherical radiation source with A = 0.75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 vii 1. INTRODUCTION If fusion energy is to be harnessed on earth, a thorough understanding of the regime called high energy density physics must...
Coupled Reactor Kinetics and Heat Transfer Model for Heat Pipe Cooled Reactors
WRIGHT,STEVEN A.; HOUTS,MICHAEL
2000-11-22T23:59:59.000Z
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.
Nonequilibrium Statistics of a Reduced Model for Energy Transfer in Waves
Tabak, Esteban G.
Nonequilibrium Statistics of a Reduced Model for Energy Transfer in Waves R. E. LEE DEVILLE Courant, with the subsequent dynamics transferring the energy to longer scales. The main dissipation mechanism is wave breaking, which usually acts on much longer (gravity) waves that intermittently remove energy from the wave system
Markmann, Andreas
and pentatetraene. Our aim is to simulate dynamically the charge transfer process when one component is artificiallyAllene and pentatetraene cations as models for intramolecular charge transfer: Vibronic coupling online 13 April 2005 We consider the vibronic coupling effects involving cationic states with degenerate
Lyon, Richard Harry, 1981-
2004-01-01T23:59:59.000Z
Correct modeling of the space environment, including radiative forces, is an important aspect of space situational awareness for geostationary (GEO) spacecraft. Solar radiation pressure has traditionally been modeled using ...
Modeling of Heat Transfer in Geothermal Heat Exchangers
Cui, P.; Man, Y.; Fang, Z.
2006-01-01T23:59:59.000Z
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...
Spreader-Bar Radiation Detection System Enhancements: A Modeling and Simulation Study
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
This report provides the modeling and simulation results of the investigation of enhanced spreader bar radiation detection systems.
Numerical and analytical modeling of heat transfer between fluid and fractured rocks
Li, Wei, S.M. Massachusetts Institute of Technology
2014-01-01T23:59:59.000Z
Modeling of heat transfer between fluid and fractured rocks is of particular importance for energy extraction analysis in EGS, and therefore represents a critical component of EGS design and performance evaluation. In ...
Tabares Velasco, P. C.
2011-04-01T23:59:59.000Z
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.'
Siewert, Charles E.
subject to Fresnel boundary and interface conditions R.D.M. Garcia a,Ã, C.E. Siewert b a Instituto de: Radiative transfer Nascent delta function Fresnel conditions Discrete-ordinates method a b s t r a c in a plane-parallel, multi-layer medium subject to Fresnel boundary and interface conditions. As a result
Schaerer, Daniel
2008-01-01T23:59:59.000Z
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 fun...
Modeling and Analysis of Solar Radiation Potentials on Building Rooftops
Omitaomu, Olufemi A [ORNL; Kodysh, Jeffrey B [ORNL; Bhaduri, Budhendra L [ORNL
2012-01-01T23:59:59.000Z
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.
Gustavsen, Arild
2009-01-01T23:59:59.000Z
of convection and radiation heat transfer and developconvection and radiation heat transfer in three dimensionsaccount for 3- D radiation heat transfer on indoor surfaces.
New flow boiling heat transfer model for hydrocarbons evaporating inside horizontal tubes
Chen, G. F.; Gong, M. Q.; Wu, J. F.; Zou, X. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, 35, Beijing, 100190 (China); Wang, S. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, 35, Beijing, 100190 (China); University of Chinese Academy of Science, No. 19 YuQuan Road, Beijing, 100049 (China)
2014-01-29T23:59:59.000Z
Hydrocarbons have high thermodynamic performances, belong to the group of natural refrigerants, and they are the main components in mixture Joule-Thomson low temperature refrigerators (MJTR). New evaluations of nucleate boiling contribution and nucleate boiling suppression factor in flow boiling heat transfer have been proposed for hydrocarbons. A forced convection heat transfer enhancement factor correlation incorporating liquid velocity has also been proposed. In addition, the comparisons of the new model and other classic models were made to evaluate its accuracy in heat transfer prediction.
Transient PVT measurements and model predictions for vessel heat transfer. Part II.
Felver, Todd G.; Paradiso, Nicholas Joseph; Winters, William S., Jr.; Evans, Gregory Herbert; Rice, Steven F.
2010-07-01T23:59:59.000Z
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.
Scalar potential model of the CMB radiation temperature
John C. Hodge
2006-03-06T23:59:59.000Z
A derivation of a theoretical, time average, cosmic microwave background (CMB), Planckian temperature V of the universe remains a challenge. A scalar potential model (SPM) that resulted from considerations of galaxy cells is applied to deriving a value for V. The heat equation is solved for a cell with the boundary conditions of SPM Source and Sink characteristics, with simplified cell characteristics, and with zero initial temperature. The universe is a collection of cells. The CMB radiation is black body radiation with the cells acting as radiators and absorbers. Conventional thermodynamics is applied to calculate V = 2.718 K. The temperature and matter content of cells are finely controlled by a feedback mechanism. Because time is required for matter to flow from Sources to Sinks, the radiation temperature of cells cycles about V after an initial growth phase. If the universe is like an ideal gas in free expansion and is not in thermal equilibrium, then the pressure and volume follow the measured CMB temperature vm = 2.725 K. Therefore, increasing vm >V equates to an expansion pressure on matter and expanding volume.
A simplified physical model for assessing solar radiation over Brazil using GOES 8 visible imagery
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 Composition and Structure: Transmission and scattering of radiation; KEYWORDS: solar radiation, satellite
Coupled Deterministic-Monte Carlo Transport for Radiation Portal Modeling
Smith, Leon E.; Miller, Erin A.; Wittman, Richard S.; Shaver, Mark W.
2008-01-14T23:59:59.000Z
Radiation portal monitors are being deployed, both domestically and internationally, to detect illicit movement of radiological materials concealed in cargo. Evaluation of the current and next generations of these radiation portal monitor (RPM) technologies is an ongoing process. 'Injection studies' that superimpose, computationally, the signature from threat materials onto empirical vehicle profiles collected at ports of entry, are often a component of the RPM evaluation process. However, measurement of realistic threat devices can be both expensive and time-consuming. Radiation transport methods that can predict the response of radiation detection sensors with high fidelity, and do so rapidly enough to allow the modeling of many different threat-source configurations, are a cornerstone of reliable evaluation results. Monte Carlo methods have been the primary tool of the detection community for these kinds of calculations, in no small part because they are particularly effective for calculating pulse-height spectra in gamma-ray spectrometers. However, computational times for problems with a high degree of scattering and absorption can be extremely long. Deterministic codes that discretize the transport in space, angle, and energy offer potential advantages in computational efficiency for these same kinds of problems, but the pulse-height calculations needed to predict gamma-ray spectrometer response are not readily accessible. These complementary strengths for radiation detection scenarios suggest that coupling Monte Carlo and deterministic methods could be beneficial in terms of computational efficiency. Pacific Northwest National Laboratory and its collaborators are developing a RAdiation Detection Scenario Analysis Toolbox (RADSAT) founded on this coupling approach. The deterministic core of RADSAT is Attila, a three-dimensional, tetrahedral-mesh code originally developed by Los Alamos National Laboratory, and since expanded and refined by Transpire, Inc. [1]. MCNP5 is used to calculate sensor pulse-height tallies. RADSAT methods, including adaptive, problem-specific energy-group creation, ray-effect mitigation strategies and the porting of deterministic angular flux to MCNP for individual particle creation are described in [2][3][4]. This paper discusses the application of RADSAT to the modeling of gamma-ray spectrometers in RPMs.
Radiation Modeling In Fluid Flow Iain D. Boyd
Wang, Wei
Collector #12;4 Fundamentals of Radiation (1) · All matter with non-zero temperature emits thermal radiation with energy flux given by the Stefan-Boltzmann Law: e.g., Sun: T=5800 K, total radiated power = 4 distribution (Planck spectrum) !q =T 4 W/m2 #12;5 Planck Radiation Spectrum #12;6 Solar Radiation Spectrum
Zhai, Pengwang
2009-06-02T23:59:59.000Z
meter. 60 20 Geometry of a scattering event. . . . . . . . . . . . . . . . . . . . . . 63 21 An example of the atmosphere model used in the 3D Monte Carlo code for the vector radiative transfer systems. Inhomogeneous layers are divided into voxels... cases can be solved analytically. Several popular numerical methods include the T-matrix method [15, 16, 17, 18, 19], finite-element method [20, 21], finite-difference time-domain(FDTD)method[22,23,24,25,26,27,28,29,30,31,32], point-matching method [33...
Measurement and modeling of transfer functions for lightning coupling into the Sago mine.
Morris, Marvin E.; Higgins, Matthew B.
2007-04-01T23:59:59.000Z
This report documents measurements and analytical modeling of electromagnetic transfer functions to quantify the ability of cloud-to-ground lightning strokes (including horizontal arc-channel components) to couple electromagnetic energy into the Sago mine located near Buckhannon, WV. Two coupling mechanisms were measured: direct and indirect drive. These transfer functions are then used to predict electric fields within the mine and induced voltages on conductors that were left abandoned in the sealed area of the Sago mine.
Temperature profile and heat transfer model for a chemical wastewater treatment plant
Brown, E.V. (CH2M HILL, Atlanta, GA (United States)); Enzminger, J.D. (CH2M HILL, Parsippany, NJ (United States))
1991-08-01T23:59:59.000Z
This paper presents a heat transfer model for equalization, activated sludge, and trickling filter unit processes than can be used to assess the effect of operating temperature on unit process selection, materials of construction selection, and heat retention and cooling requirements. In developing this model, the individual variables that affect the operating temperature of biological systems were first identified. Mathematical relationships were then developed to describe system behavior, based on conservation laws and rate equations. The heat transfer models were then used to developed a temperature profile of the two alternative WWTP configurations.
Radiative hydrodynamic modelling and observations of the X-class solar flare on 2011 March 9
Kennedy, Michael B; Allred, Joel C; Mathioudakis, Mihalis; Keenan, Francis P
2015-01-01T23:59:59.000Z
We investigated the response of the solar atmosphere to non-thermal electron beam heating using the radiative transfer and hydrodynamics modelling code RADYN. The temporal evolution of the parameters that describe the non-thermal electron energy distribution were derived from hard X-ray observations of a particular flare, and we compared the modelled and observed parameters. The evolution of the non-thermal electron beam parameters during the X1.5 solar flare on 2011 March 9 were obtained from analysis of RHESSI X-ray spectra. The RADYN flare model was allowed to evolve for 110 seconds, after which the electron beam heating was ended, and was then allowed to continue evolving for a further 300s. The modelled flare parameters were compared to the observed parameters determined from extreme-ultraviolet spectroscopy. The model produced a hotter and denser flare loop than that observed and also cooled more rapidly, suggesting that additional energy input in the decay phase of the flare is required. In the explosi...
Hickman, A. E.
We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical–ecosystem component in a dynamic three-dimensional physical framework. The radiative transfer ...
Nonlinear State Space Model of a Hydraulic Wind Power Transfer Masoud Vaezi1
Zhou, Yaoqi
Nonlinear State Space Model of a Hydraulic Wind Power Transfer Masoud Vaezi1 , Majid Deldar1 1, IUPUI. Gearless hydraulic wind power systems are considered as nonlinear models because of some discrete nonlinear governing equations for the elements in the proposed hydraulic wind power configuration. Nonlinear
Direct Modeling of Material Deposit and Identification of Energy Transfer in Gas Metal Arc Welding
Paris-Sud XI, Université de
Direct Modeling of Material Deposit and Identification of Energy Transfer in Gas Metal Arc Welding sources for finite element simulation of gas metal arc welding (GMAW). Design for the modeling of metal deposition results in a direct calculation of the formation of the weld bead, without any
Zollman, Dean
in order to understand the image construction process in PET. For this purpose we conduct teaching of learning from the models of the activities to the PET image construction process. #12;METHODOLOGY Sixteen of the physical models in transferring physics ideas to understanding positron emission tomography technology
A Small Artery Heat Transfer Model for Self-Heated Thermistor Measurements of Perfusion in the
A Small Artery Heat Transfer Model for Self-Heated Thermistor Measurements of Perfusion model (SAM) for self-heated thermistor measurements of perfusion in the canine kidney is developed based clinical method to quantify perfusion for a majority of applications. Self-heated thermistor techniques
A Shell Model for Atomistic Simulation of Charge Transfer in...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
polarons, respectively, are modeled by delocalizing the polaron’s charge over a titanium or oxygen ion, respectively, and its first nearest-neighbors. The charge...
Compendium of Material Composition Data for Radiation Transport Modeling
McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert
2011-03-04T23:59:59.000Z
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.
Running of Radiative Neutrino Masses: The Scotogenic Model
Romain Bouchand; Alexander Merle
2012-04-30T23:59:59.000Z
We study the renormalization group equations of Ma's scotogenic model, which generates an active neutrino mass at 1-loop level. In addition to other benefits, the main advantage of the mechanism exploited in this model is to lead to a natural loop-suppression of the neutrino mass, and therefore to an explanation for its smallness. However, since the structure of the neutrino mass matrix is altered compared to the ordinary type I seesaw case, the corresponding running is altered as well. We have derived the full set of renormalization group equations for the scotogenic model which, to our knowledge, had not been presented previously in the literature. This set of equations reflects some interesting structural properties of the model, and it is an illustrative example for how the running of neutrino parameters in radiative models is modified compared to models with tree-level mass generation. We also study a simplified numerical example to illustrate some general tendencies of the running. Interestingly, the structure of the RGEs can be exploited such that a bimaximal leptonic mixing pattern at the high-energy scale is translated into a valid mixing pattern at low energies, featuring a large value of \\theta_{13}. This suggests very interesting connections to flavour symmetries.
, Kuadasi, Turkey RAD-13-040 SPECTRAL RADIATIVE PROPERTIES OF THREE-DIMENSIONALLY ORDERED MACROPOROUS CERIA
Energy transfers in shell models for MHD turbulence
T. Lessinnes; M. K. Verma; D. Carati
2008-07-31T23:59:59.000Z
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.
Hammes-Schiffer, Sharon
Model Proton-Coupled Electron Transfer Reactions in Solution: Predictions of Rates, Mechanisms isotope effects for proton-coupled electron transfer (PCET) reactions. These studies are based, the solvent is represented as a dielectric continuum, and the active electrons and transferring protons
Nuisance Source Population Modeling for Radiation Detection System Analysis
Sokkappa, P; Lange, D; Nelson, K; Wheeler, R
2009-10-05T23:59:59.000Z
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.
Radiative cooling of laser ablated vapor plumes: experimental and theoretical analyses
Wen, Sy-Bor; Mao, Xianglei; Grief, Ralph; Russo, Richard E.
2006-01-01T23:59:59.000Z
J. , Thermal radiation heat transfer, 4 th ed, (Taylor &in the calculation of the radiation heat transfer, only thelines, the thermal radiation heat transfer is given by [16
Chardin, Jonathan; Aubert, Dominique; Puchwein, Ewald
2015-01-01T23:59:59.000Z
We calibrate here cosmological radiative transfer simulation with ATON/RAMSES with a range of measurements of the Lyman alpha opacity from QSO absorption spectra. We find the Lyman alpha opacity to be very sensitive to the exact timing of hydrogen reionisation. Models reproducing the measured evolution of the mean photoionisation rate and average mean free path reach overlap at z ~ 7 and predict an accelerated evolution of the Lyman alpha opacity at z > 6 consistent with the rapidly evolving luminosity function of Lyman alpha emitters in this redshift range. Similar to "optically thin" simulations our full radiative transfer simulations fail, however, to reproduce the high-opacity tail of the Lyman alpha opacity PDF at z > 5. We argue that this is due to spatial UV fluctuations in the post-overlap phase of reionisation on substantially larger scales than predicted by our source model, where the ionising emissivity is dominated by large numbers of sub-L* galaxies. We further argue that this suggests a signific...
Validation of the Poisson Stochastic Radiative Transfer Model Against Cloud Cascade Models
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (MillionStructural Basis of5, 2014 |and Terry M.38 4.23Validation DataArchived CERES Surface
Evaluating the present-day simulation of clouds, precipitation, and radiation in climate models
Robert, Pincus
, and net cloud radiative effect, projected cloud fraction, and surface precipitation rate) over the globalEvaluating the present-day simulation of clouds, precipitation, and radiation in climate models] This paper describes a set of metrics for evaluating the simulation of clouds, radiation, and precipitation
USING LEARNING MACHINES TO CREATE SOLAR RADIATION MAPS FROM NUMERICAL WEATHER PREDICTION MODELS,
Paris-Sud XI, UniversitÃ© de
USING LEARNING MACHINES TO CREATE SOLAR RADIATION MAPS FROM NUMERICAL WEATHER PREDICTION MODELS to develop a methodology to generate solar radiation maps using information from different sources. First with conclusions and next works in the last section. Keywords: Solar Radiation maps, Numerical Weather Predictions
An enriched finite element model with q-refinement for radiative boundary layers in glass cooling
Mohamed, M. Shadi [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Seaid, Mohammed; Trevelyan, Jon [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom)] [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Laghrouche, Omar [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)
2014-02-01T23:59:59.000Z
Radiative cooling in glass manufacturing is simulated using the partition of unity finite element method. The governing equations consist of a semi-linear transient heat equation for the temperature field and a stationary simplified P{sub 1} approximation for the radiation in non-grey semitransparent media. To integrate the coupled equations in time we consider a linearly implicit scheme in the finite element framework. A class of hyperbolic enrichment functions is proposed to resolve boundary layers near the enclosure walls. Using an industrial electromagnetic spectrum, the proposed method shows an immense reduction in the number of degrees of freedom required to achieve a certain accuracy compared to the conventional h-version finite element method. Furthermore the method shows a stable behaviour in treating the boundary layers which is shown by studying the solution close to the domain boundaries. The time integration choice is essential to implement a q-refinement procedure introduced in the current study. The enrichment is refined with respect to the steepness of the solution gradient near the domain boundary in the first few time steps and is shown to lead to a further significant reduction on top of what is already achieved with the enrichment. The performance of the proposed method is analysed for glass annealing in two enclosures where the simplified P{sub 1} approximation solution with the partition of unity method, the conventional finite element method and the finite difference method are compared to each other and to the full radiative heat transfer as well as the canonical Rosseland model.
Kitzmann, D; Rauer, H
2013-01-01T23:59:59.000Z
Owing to their wavelengths dependent absorption and scattering properties, clouds have a strong impact on the climate of planetary atmospheres. Especially, the potential greenhouse effect of CO2 ice clouds in the atmospheres of terrestrial extrasolar planets is of particular interest because it might influence the position and thus the extension of the outer boundary of the classic habitable zone around main sequence stars. We study the radiative effects of CO2 ice particles obtained by different numerical treatments to solve the radiative transfer equation. The comparison between the results of a high-order discrete ordinate method and simpler two-stream approaches reveals large deviations in terms of a potential scattering efficiency of the greenhouse effect. The two-stream methods overestimate the transmitted and reflected radiation, thereby yielding a higher scattering greenhouse effect. For the particular case of a cool M-type dwarf the CO2 ice particles show no strong effective scattering greenhouse eff...
Models for Metal Hydride Particle Shape, Packing, and Heat Transfer
Kyle C. Smith; Timothy S. Fisher
2012-05-04T23:59:59.000Z
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.
An Efficient Instantiation Algorithm for Simulating Radiant Energy Transfer in Plant Models
Boyer, Edmond
An Efficient Instantiation Algorithm for Simulating Radiant Energy Transfer in Plant Models Cyril CIRAD/INRIA We describe a complete lighting simulation system tailored for the difficult case growth simulation. Other applications of our system range from landscape simulation to agronomical
Development of Property-Transfer Models for Estimating the Hydraulic Properties of Deep
Development of Property-Transfer Models for Estimating the Hydraulic Properties of Deep Sediments at the Idaho National Engineering and Environmental Laboratory, Idaho Scientific Investigations Report 2005 Survey DOE/ID-22196 #12;Cover: Graph showing example of water-retention (q(y)) curve showing components
On exact and perturbation solutions to nonlinear equations for heat transfer models
Francisco M. Fernández
2009-11-03T23:59:59.000Z
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.
Heat and Mass Transfer Modeling of Dry Gases in the Cathode of PEM Fuel Cells
Stockie, John
Heat and Mass Transfer Modeling of Dry Gases in the Cathode of PEM Fuel Cells M.J. Kermani1 J and N2, through the cathode of a proton exchange membrane (PEM) fuel cell is studied numerically) an energy equation, written in a form that has enthalpy as the dependent variable. Keywords: PEM fuel cells
FLUID FLOW MODELING OF RESIN TRANSFER MOLDING FOR COMPOSITE MATERIAL WIND TURBINE BLADE STRUCTURES
FLUID FLOW MODELING OF RESIN TRANSFER MOLDING FOR COMPOSITE MATERIAL WIND TURBINE BLADE STRUCTURES parents and Ashley for their encouragement and patience through out this process. Without your support I and helped with the testing and data acquisition for the fabric compression tests. Russ's help with gathering
Mass Transfer Models for Hydrolysis 965 Applied Biochemistry and Biotechnology Vol. 113116, 2004
California at Riverside, University of
Mass Transfer Models for Hydrolysis 965 Applied Biochemistry and Biotechnology Vol. 113116, 2004 economic, environmental, and strategic benefits (1). Accurate, predictive tools would be valuable Biochemistry and Biotechnology Vol. 113116, 2004 ity (2). For example, significant differences are observed
Modeling the free energy surfaces of electron transfer in condensed phases
Matyushov, Dmitry
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
Model for energy transfer by coherent Fermi pressure fluctuations in quantum soft matter
Peterson, Mark A
2015-01-01T23:59:59.000Z
A 1-dimensional model for coherent quantum energy transfer through a complex of compressible boxes is investigated by numerical integration of the time-dependent Schr\\"odinger equation. Energy is communicated from one box to the next by the resonant fluctuating Fermi pressure of the electrons in each box pushing on the walls and doing work on adjacent boxes. Parameters are chosen similar to the chain molecules of typical light harvesting complexes. For some parameter choices the system is found to have an instability leading to self-induced coherent energy transfer transparency.
New model of calculating the energy transfer efficiency for the spherical theta-pinch device
Xu, G; Loisch, G; Xiao, G; Jacoby, J; Weyrich, K; Li, Y; Zhao, Y
2015-01-01T23:59:59.000Z
Ion-beam-plasma-interaction plays an important role in the field of Warm Dense Matter (WDM) and Inertial Confinement Fusion (ICF). A spherical theta pinch is proposed to act as a plasma target in various applications including a plasma stripper cell. One key parameter for such applications is the free electron density. A linear dependency of this density to the amount of energy transferred into the plasma from an energy storage was found by C. Teske. Since the amount of stored energy is known, the energy transfer efficiency is a reliable parameter for the design of a spherical theta pinch device. The traditional two models of energy transfer efficiency are based on assumptions which comprise the risk of systematical errors. To obtain precise results, this paper proposes a new model without the necessity of any assumption to calculate the energy transfer efficiency for an inductively coupled plasma device. Further, a comparison of these three different models is given at a fixed operation voltage for the full ...
Bioheat Transfer Valvano, page 1 Bioheat Transfer
a technically challenging task. First, tissue heat transfer includes conduction, convection, radiation and by heat transfer due to blood flow near the probe. In vivo, the instrument measures effective thermal properties that are the combination of conductive and convective heat transfer. Thermal properties
Light Transfer Simulation Tools in Photobiological Fuel Production
Lee, Euntaek
2013-01-01T23:59:59.000Z
and M. P. Meng¨ u¸c, “Radiation heat transfer in combustionand radiation in the Atlas plume”, Journal of Thermophysics and Heat Transfer,Thermal radiation is a dominant mode of heat transfer in
Jia, S.; Chung, B.T.F. [Univ. of Akron, OH (United States). Dept. of Mechanical Engineering
1996-12-31T23:59:59.000Z
Based on a previously proposed non-linear turbulence model, a turbulent heat transfer model is formulated in the present study using the concept of Generalized Gradient Diffusion (GGD) hypothesis. Under this hypothesis, an anisotropic thermal diffusivity can be obtained through the proposed non-linear turbulent model which is applied to the turbulent flow and heat transfer in a sudden expansion pipe with a constant heat flux through the pipe wall. The numerical results are compared with the available experimental data for both turbulent and thermal quantities, with an emphasis on the non-linear heat transfer predictions. The improved results are obtained for the bulk temperature distribution showing that the present non-linear heat transfer model is capable of predicting the anisotropic turbulent heat transfer for the pipe expansion flow. Some limits of the proposed model are also identified and discussed.
Penetration of solar radiation in the upper ocean: A numerical model for oceanic and coastal waters
Lee, Zhongping
Penetration of solar radiation in the upper ocean: A numerical model for oceanic and coastal waters (2005), Penetration of solar radiation in the upper ocean: A numerical model for oceanic and coastal; Siegel et al., 1995] have demonstrated that the penetration of EVIS in the upper layer of the ocean plays
Modeling ofHybrid (Heat Radiation and Microwave) High Temperature Processing ofLimestone
Yakovlev, Vadim
Modeling ofHybrid (Heat Radiation and Microwave) High Temperature Processing ofLimestone Shawn M (electromagnetic and thermal) modeling to cover practically valuable scenarios of hybrid (heat radiation is applied to the process of hybrid heating of cylindrical samples of limestone in Ceralink's MAT TM kiln
Intercomparison of Single-Column Numerical Models for the Prediction of Radiation Fog
Intercomparison of Single-Column Numerical Models for the Prediction of Radiation Fog THIERRY-term forecasting of fog is a difficult issue that can have a large societal impact. Radiation fog appears layers of the atmosphere. Current NWP models poorly forecast the life cycle of fog, and improved NWP
Stochastic modeling of the cell killing effect for low- and high-LET radiation
Partouche, Julien
2005-02-17T23:59:59.000Z
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...
Stochastic modeling of the cell killing effect for low- and high-LET radiation
Partouche, Julien
2005-02-17T23:59:59.000Z
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 ...
Modelled Black Carbon Radiative Forcing and Atmospheric Lifetime...
Office of Scientific and Technical Information (OSTI)
AeroCom Phase II Constrained by Aircraft Observations Black carbon (BC) aerosols absorb solar radiation, and are generally held to exacerbate global warming through exerting a...
ON THE SOLAR RADIATION BUDGET AND THE CLOUD ABSORPTION ANOMALY DEBATE
Li, Zhanqing
ON THE SOLAR RADIATION BUDGET AND THE CLOUD ABSORPTION ANOMALY DEBATE ZHANQING LI Department-of-the-art radiative transfer models. 1. Introduction Solar radiation is the ultimate source of energy for the planet of solar radiation, which is unfortunately still fraught with large uncertainties (Wild et al. 1995; Li et
Deru, M.; Judkoff, R.; Neymark, J.
2002-08-01T23:59:59.000Z
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.
Impeded inverse energy transfer in the Charney--Hasegawa--Mima model of quasi-geostrophic flows
Chuong V. Tran; David G. Dritschel
2005-12-02T23:59:59.000Z
The behaviour of turbulent flows within the single-layer quasi-geostrophic (Charney--Hasegawa--Mima) model is shown to be strongly dependent on the Rossby deformation wavenumber $\\lambda$ (or free-surface elasticity). Herein, we derive a bound on the inverse energy transfer, specifically on the growth rate $\\d\\ell/\\dt$ of the characteristic length scale $\\ell$ representing the energy centroid. It is found that $\\d\\ell/\\dt\\le2\
Application of an EASM model for turbulent convective heat transfer in ribbed duct
Saidi, A.; Sunden, B.
1999-07-01T23:59:59.000Z
A numerical investigation is performed to predict local and mean thermal-hydraulic characteristics in rib-roughened ducts. The Navier-Stokes and energy equations, and a low-Re number {kappa}-{epsilon} turbulence model are solved with two methods for determination of the Reynolds stresses, eddy viscosity model (EVM) and explicit algebraic stress model (EASM). The numerical solution procedure uses a collocated grid, and the pressure-velocity coupling is handled by the SIMPLEC algorithm. The assumption of fully developed periodic conditions is applied. The calculated mean and local heat transfer enhancement values are compared with experimental data and fairly good agreement on mean Nu numbers is achieved. The prediction capabilities of the two turbulence models (EVM and EASM) are discussed. Both models have similar ability to predict the mean Nusselt numbers but the EASM model is superior in description of the flow field structure.
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
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.
Robertson, David E.; Cataldo, Dominic A.; Napier, Bruce A.; Krupka, Kenneth M.; Sasser, Lyle B.
2003-07-20T23:59:59.000Z
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 cow’s milk, sheep’s milk, goat’s 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.
Minnesota, University of
Design and Testing of a Heat Transfer Model of a Raccon (Procyon Lotor) in a Closed Tree Den Author. http://www.jstor.org #12;Ecology (1974) 55: pp. 29-39 DESIGN AND TESTING OF A HEAT TRANSFER MODEL
Effect of non-standard interaction for radiative neutrino mass model
Konishi, Y.; Sato, J.; Shimomura, T. [Department of Physics, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570 (Japan); Department of Physics, Niigata University, Niigata, 950-2181 (Japan)
2012-07-27T23:59:59.000Z
We examined effects of non-standard interactions (NSIs) in a radiative neutrino mass model. The radiative neutrino mass model suggested by Kraus Nasri and Trodden can explain not only neutrino flavor mixing and neutrino masses, but also dark matter relic abundance. Although the NSI effects of the model are too small to be detected by present neutrino oscillation experiments, we might observe the small effects in future experiments such as neutrino factory.
Huang, Yi
The properties of thermal radiation exchange between hot and cold objects can be strongly modified if they interact in the near field where electromagnetic coupling occurs across gaps narrower than the dominant wavelength ...
Dalgicdir, Cahit; Sensoy, Ozge; Sayar, Mehmet, E-mail: msayar@ku.edu.tr [College of Engineering, Koç University, 34450 Istanbul (Turkey)] [College of Engineering, Koç University, 34450 Istanbul (Turkey); Peter, Christine [Max Planck Institute for Polymer Research, 55128 Mainz (Germany) [Max Planck Institute for Polymer Research, 55128 Mainz (Germany); Department of Chemistry, University of Konstanz, 78547 Konstanz (Germany)
2013-12-21T23:59:59.000Z
One of the major challenges in the development of coarse grained (CG) simulation models that aim at biomolecular structure formation processes is the correct representation of an environment-driven conformational change, for example, a folding/unfolding event upon interaction with an interface or upon aggregation. In the present study, we investigate this transferability challenge for a CG model using the example of diphenylalanine. This dipeptide displays a transition from a trans-like to a cis-like conformation upon aggregation as well as upon transfer from bulk water to the cyclohexane/water interface. Here, we show that one can construct a single CG model that can reproduce both the bulk and interface conformational behavior and the segregation between hydrophobic/hydrophilic medium. While the general strategy to obtain nonbonded interactions in the present CG model is to reproduce solvation free energies of small molecules representing the CG beads in the respective solvents, the success of the model strongly depends on nontrivial decisions one has to make to capture the delicate balance between the bonded and nonbonded interactions. In particular, we found that the peptide's conformational behavior is qualitatively affected by the cyclohexane/water interaction potential, an interaction that does not directly involve the peptide at all but merely influences the properties of the hydrophobic/hydrophilic interface. Furthermore, we show that a small modification to improve the structural/conformational properties of the CG model could dramatically alter the thermodynamic properties.
Measured radiation patterns of the scale model dipole tool
Lu, Rongrong
2003-01-01T23:59:59.000Z
The sound field of finite dipole acoustic transducers in a steel tool was investigated and their horizontal by measuring their vertical radiation patterns in water at two different frequencies. Measurements were also made ...
Keene, William C. [University of Virginia] [University of Virginia; Long, Michael S. [University of Virginia] [University of Virginia
2013-05-20T23:59:59.000Z
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 Chemistryâ??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 Earthâ??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.
Hogan, Robin
A 3D STOCHASTIC CLOUD MODEL FOR INVESTIGATING THE RADIATIVE PROPERTIES OF INHOMOGENEOUS CIRRUS CLOUDS Robin J. Hogan and Sarah F. Kew ¡ Department of Meteorology, University of Reading, Reading, Berkshire, United Kingdom 1 INTRODUCTION The importance of ice clouds on the earth's radiation budget
Modelling dynamics of samples exposed to free-electron-laser radiation with Boltzmann equations
Beata Ziaja; Antonio R. B. de Castro; Edgar Weckert; Thomas Moeller
2005-12-20T23:59:59.000Z
We apply Boltzmann equations for modelling the radiation damage in samples irradiated by photons from free electron laser (FEL). We test this method in a study case of a spherically symmetric xenon cluster irradiated with VUV FEL photons. The results obtained demonstrate the potential of the Boltzmann method for describing the complex and non-equilibrium dynamics of samples exposed to FEL radiation.
A Generalized Pyrolysis Model for Combustible Solids
Lautenberger, Chris
2007-01-01T23:59:59.000Z
fluid mechanics, heat transfer, radiation, and combustion toJ.R. , Thermal Radiation Heat Transfer . Third Edition,to account for radiation heat transfer across pores. The
S. L. Lebedev
2005-12-19T23:59:59.000Z
The effect of radiation polarization attended with the motion of spinning charge in the magnetic field could be viewed through the classical theory of self-interaction. The quantum expression for the polarization time follows from the semiclassical relation $T_{QED}\\sim \\hbar c^{3}/\\mu_{B}^2\\omega_{c}^3$, and needs quantum explanation neither for the orbit nor for the spin motion. In our approach the polarization emerges as a result of natural selection in the ensenmble of elastically scattered electrons among which the group of particles that bear their spins in the 'right' directions has the smaller probability of radiation. The evidence of non-complete polarization degree is also obtained.
A modified lattice Bhatnagar-Gross-Krook model for convection heat transfer in porous media
Wang, Liang; Guo, Zhaoli
2015-01-01T23:59:59.000Z
The lattice Bhatnagar-Gross-Krook (LBGK) model has become the most popular one in the lattice Boltzmann method for simulating the convection heat transfer in porous media. However, the LBGK model generally suffers from numerical instability at low fluid viscosities and effective thermal diffusivities. In this paper, a modified LBGK model is developed for incompressible thermal flows in porous media at the representative elementary volume scale, in which the shear rate and temperature gradient are incorporated into the equilibrium distribution functions. With two additional parameters, the relaxation times in the collision process can be fixed at a proper value invariable to the viscosity and the effective thermal diffusivity. In addition, by constructing a modified equilibrium distribution function and a source term in the evolution equation of temperature field, the present model can recover the macroscopic equations correctly through the Chapman-Enskog analysis, which is another key point different from pre...
A Heat Transfer Model for a Stratified Corium-Metal Pool in the Lower Plenum of a Nuclear Reactor
M. S. Sohal; L. J. Siefken
1999-08-01T23:59:59.000Z
This preliminary design report describes a model for heat transfer in a corium-metal stratified pool. It was decided to make use of the existing COUPLE model. Currently available correlations for natural convection heat transfer in a pool with and without internal heat generation were obtained. The appropriate correlations will be incorporated in the existing COUPLE model. Heat conduction and solidification modeling will be done with existing algorithms in the COUPLE. Assessment of the new model will be done by simple energy conservation problems.
A Heat Transfer Model for a Stratified Corium-metal Pool in the Lower Plenum of a Nuclear Reactor
Sohal, Manohar Singh; Siefken, Larry James
1999-08-01T23:59:59.000Z
This preliminary design report describes a model for heat transfer in a corium-metal stratified pool. It was decided to make use of the existing COUPLE model. Currently available correlations for natural convection heat transfer in a pool with and without internal heat generation were obtained. The appropriate correlations will be incorporated in the existing COUPLE model. Heat conduction and solidification modeling will be done with existing algorithms in the COUPLE. Assessment of the new model will be done by simple energy conservation problems.
Kravis, S. D.; Church, David A.; Johnson, B. M.; Meron, M.; Jones, K. W.; Levin, J. C.; Sellin, I. A.; Azuma, Y.; Berrahmansour, N.; Berry, H. G.; Druetta, M.
1992-01-01T23:59:59.000Z
-shell photoionization of Ar atoms, using broadband synchrotron x-ray radiation. K-electron removal resulted in vacancy cascading, yielding a distribution of argon-ion charge states peaked near Ar4+. The stored ion gas had an initial temperature near 480 K. The basic...
Methodology A simple linear model for radiative forcing of absorbing
Peters, Karsten
Absorbing aerosol in cloudy scenes: effects on atmospheric radia7on Aerosol Cloud Cloud prevents aerosol-radiation interaction; small negative forcing, i.e. COOLING Indirect rather than direct effect through modification of cloud properties Cloud enhances "surface albedo"; potentially large
Modeling the heat transfer in geometrically complex media with a volume source
Gurevich, M. I., E-mail: gur.m@mail.ru; Tel’kovskaya, O. V.; Chukbar, B. K.; Shkarovskiy, D. A. [National Research Center Kurchatov Institute (Russian Federation)
2014-12-15T23:59:59.000Z
Fuel elements produced from spent fuel are porous media with spatially varying characteristics. A hierarchical discrete structure for the numerical modeling of heat-transfer processes in media with an anisotropic geometry that is characterized by both the microscopic voids and macroscopic changes in the parameters is proposed. The basic unit of the structure at its lower level is a cell that represents the local properties of the medium. The cells have a standard interface that allows one to form three-dimensional networks of such cells. Different types of cells in the network represent macroscopic changes. The potential for parallel processing is analyzed.
Mathematical modeling of mass transfer during centrifugal filtration of polydisperse suspensions
V.F. Pozhidaev; Y.B. Rubinshtein; G.Y. Golberg; S.A. Osadchii [Dahl East Ukraine National University, Lugansk (Ukraine)
2009-07-15T23:59:59.000Z
A mass-transfer equation, the solution of which for given boundary conditions makes it possible to derive in analytical form a relationship between the extraction of the solid phase of a suspension into the centrifuge effluent and the fineness of the particles, is suggested on the basis of a model; this is of particular importance in connection with the development of a new trend in the utilization of filtering centrifuges - concentration of coal slurries by extraction into the centrifuge effluent of the finest particles, the ash content of which is substantially higher than that of particles of the coarser classes. Results are presented for production studies under conditions at an active establishment (the Neryungrinskaya Enrichment Factory); these results confirmed the adequacy of the mathematical model proposed: convergence of computed and experimental data was within the limits of the experimental error (no more than 3%). The model in question can be used to predict results of suspension separation by centrifugal filtration.
A physical model of radiated enhancement of plasma-surrounded antenna
Gao, Xiaotian; Wang, Chunsheng, E-mail: wangcs@hit.edu.cn; Jiang, Binhao; Zhang, Zhonglin [Harbin Institute of Technology, 92 West Dazhi Street, Nan Gang District, 150001 Harbin (China)
2014-09-15T23:59:59.000Z
A phenomenon that the radiated power may be enhanced when an antenna is surrounded by a finite plasma shell has been found in numerical and experimental studies. In this paper, a physical model was built to express the mechanism of the radiated enhancement. In this model, the plasma shell is treated as a parallel connection of a capacitance and a conductance whose parameters change with the system parameters (plasma density, collision frequency, and antenna frequency). So, the radiated enhancement can be explained by the resonance between the plasma shell and the infinite free space. Furthermore, the effects of system parameters on the radiated power are given and effects corresponding to mechanisms are performed based on the physical model.
Viscous boundary layers of radiation-dominated, relativistic jets. II. The free-streaming jet model
Coughlin, Eric R
2015-01-01T23:59:59.000Z
We analyze the interaction of a radiation-dominated jet and its surroundings using the equations of radiation hydrodynamics in the viscous limit. In a previous paper we considered the two-stream scenario, which treats the jet and its surroundings as distinct media interacting through radiation viscous forces. Here we present an alternative boundary layer model, known as the free-streaming jet model -- where a narrow stream of fluid is injected into a static medium -- and present solutions where the flow is ultrarelativistic and the boundary layer is dominated by radiation. It is shown that these jets entrain material from their surroundings and that their cores have a lower density of scatterers and a harder spectrum of photons, leading to observational consequences for lines of sight that look "down the barrel of the jet." These jetted outflow models may be applicable to the jets produced during long gamma-ray bursts and super-Eddington phases of tidal disruption events.
Electrostatic models of electron-driven proton transfer across a lipid membrane
Anatoly Yu. Smirnov; Lev G. Mourokh; Franco Nori
2010-11-29T23:59:59.000Z
We present two models for electron-driven uphill proton transport across lipid membranes, with the electron energy converted to the proton gradient via the electrostatic interaction. In the first model, associated with the cytochrome c oxidase complex in the inner mitochondria membranes, the electrostatic coupling to the site occupied by an electron lowers the energy level of the proton-binding site, making the proton transfer possible. In the second model, roughly describing the redox loop in a nitrate respiration of E. coli bacteria, an electron displaces a proton from the negative side of the membrane to a shuttle, which subsequently diffuses across the membrane and unloads the proton to its positive side. We show that both models can be described by the same approach, which can be significantly simplified if the system is separated into several clusters, with strong Coulomb interaction inside each cluster and weak transfer couplings between them. We derive and solve the equations of motion for the electron and proton creation/annihilation operators, taking into account the appropriate Coulomb terms, tunnel couplings, and the interaction with the environment. For the second model, these equations of motion are solved jointly with a Langevin-type equation for the shuttle position. We obtain expressions for the electron and proton currents and determine their dependence on the electron and proton voltage build-ups, on-site charging energies, reorganization energies, temperature, and other system parameters. We show that the quantum yield in our models can be up to 100% and the power-conversion efficiency can reach 35%.
Application of a transient heat transfer model for bundled, multiphase pipelines
Brown, T.S.; Clapham, J.; Danielson, T.J.; Harris, R.G.; Erickson, D.D.
1996-12-31T23:59:59.000Z
A computer model has been developed which accurately describes transient heat transfer in pipeline bundles. An arbitrary number of internal pipelines containing different fluids, flowing in either direction along with the input of heat to one or more of the fluids can be accommodated. The model is coupled to the transient, multiphase flow simulator OLGA. The lines containing the multiphase production fluids are modeled by OLGA, and the heat transfer between the internal lines, carrier pipe, and surroundings is handled by the bundle model. The model has been applied extensively to the design of a subsea, heated bundle system for the Britannia gas condensate field in the North Sea. The 15-km bundle system contains a 14{double_prime} production line, an 8{double_prime} test line, a 3{double_prime} methanol line, and a 12{double_prime} internal heating medium line within a 37.25{double_prime} carrier. The heating medium (water) flows in the internal heating medium line and in the annulus at 82,500 BPD. The primary purpose of the bundle system is to avoid the formation of hydrates. A secondary purpose is to avoid the deposition of paraffin. The bundle model was used to (1) compare the merits of two coaxial lines vs. a single bundle; (2) optimize the insulation levels on the carrier and internal lines; (3) determine the minimum time required to heat up the bundle; (4) determine heat input requirements to avoid hydrates throughout the field life, (5) determine temperature profiles along the lines for a range of production rates; (6) study ruptures of the production line into the bundle annulus; (7) determine minimum temperatures during depressurization; and (8) determine cool-down times. The results of these studies were used to size lines, select insulation levels, assess erosion potential, design for thermal expansion-induced stresses, and to select materials of construction.
Irreversible Processes in a Universe modelled as a mixture of a Chaplygin gas and radiation
G. M. Kremer
2003-03-26T23:59:59.000Z
The evolution of a Universe modelled as a mixture of a Chaplygin gas and radiation is determined by taking into account irreversible processes. This mixture could interpolate periods of a radiation dominated, a matter dominated and a cosmological constant dominated Universe. The results of a Universe modelled by this mixture are compared with the results of a mixture whose constituents are radiation and quintessence. Among other results it is shown that: (a) for both models there exists a period of a past deceleration with a present acceleration; (b) the slope of the acceleration of the Universe modelled as a mixture of a Chaplygin gas with radiation is more pronounced than that modelled as a mixture of quintessence and radiation; (c) the energy density of the Chaplygin gas tends to a constant value at earlier times than the energy density of quintessence does; (d) the energy density of radiation for both mixtures coincide and decay more rapidly than the energy densities of the Chaplygin gas and of quintessence.
A Prospective Cohort Study on Radiation-induced Hypothyroidism: Development of an NTCP Model
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
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.
ICRCCM Phase 2: Verification and calibration of radiation codes in climate models
Ellingson, R.G.; Wiscombe, W.J.; Murcray, D.; Smith, W.; Strauch, R.
1992-01-01T23:59:59.000Z
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). The data collected during SPECTRE 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. This report summarizes the activities of our group during the project's Third year to meet our stated objectives. The report is divided into three sections entitled: SPECTRE Activities, ICRCCM Activities, and summary information. The section on SPECTRE activities summarizes the field portion of the project during 1991, and the data reduction/analysis performed by the various participants. The section on ICRCCM activities summarizes our initial attempts to select data for distribution to ICRCCM participants and at comparison of observations with calculations as will be done by the ICRCCM participants. The Summary Information section lists data concerning publications, presentations, graduate students supported, and post-doctoral appointments during the project.
Efficiency Factors and Radiation Characteristics of Spherical Scatterers in Absorbing Media
Yin, Juan; Pilon, Laurent
2006-01-01T23:59:59.000Z
Howell, Thermal radiation heat transfer - Third Edition,properties, and heat, mass, and radiation transfer”, Journalradiation characteristics of fused quartz containing bubbles”, Journal of Thermophysics and Heat Transfer, (
Smith, R. M.; Liu, B.; Bai, J.; Wang, T., E-mail: t.wang@sheffield.ac.uk [Department of Electrical and Electronic Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)
2014-10-27T23:59:59.000Z
Hybrid organic/inorganic white light emitting structures have been fabricated based on a combination of high efficiency InGaN/GaN multiple quantum well (MQW) nanorod arrays and a yellow emitting co-polymer F8BT, leading to a minimised separation between them in order to achieve high efficiency non-radiative energy transfer (NRET). The NRET efficiency has been found 6.7 times higher at room temperature than at 7?K. This is attributed to the existence of strong exciton localization the InGaN MQWs, which can undergo thermally activated delocalization at high temperatures. The enhanced NRET efficiency is not only due to the delocalized MQW excitons, but also enhanced by the increased exciton diffusion at higher temperatures. This behaviour highlights the potential for high efficiency NRET in down-conversion hybrid white light emitting diodes operating at room temperature.
The $^{136}$Xe + $^{208}$Pb reaction: A test of models of multi-nucleon transfer reactions
J. S. Barrett; R. Yanez; W. Loveland; S. Zhu; A. D. Ayangeakaa; M. P. Carpenter; J. P. Greene; R. V. F. Janssens; T. Lauritsen; E. A. McCutchan; A. A. Sonzogni; C. J. Chiara; J. L. Harker; W. B. Walters
2015-05-01T23:59:59.000Z
The yields of over 200 projectile-like fragments (PLFs) and target-like fragments (TLFs) from the interaction of (E$_{c.m.}$=450 MeV) $^{136}$Xe with a thick target of $^{208}$Pb were measured using Gammasphere and off-line $\\gamma$-ray spectroscopy, giving a comprehensive picture of the production cross sections in this reaction.The measured yields were compared to predictions of the GRAZING model and the predictions of Zagrebaev and Greiner using a quantitative metric, the theory evaluation factor, {\\bf tef}. The GRAZING model predictions are adequate for describing the yields of nuclei near the target or projectile but grossly underestimate the yields of all other products. The predictions of Zagrebaev and Greiner correctly describe the magnitude and maxima of the observed TLF transfer cross sections for a wide range of transfers ($\\Delta$Z = -8 to $\\Delta$Z = +2). However for $\\Delta$Z =+4, the observed position of the maximum in the distribution is four neutrons richer than the predicted maximum. The predicted yields of the neutron-rich N=126 nuclei exceed the measured values by two orders of magnitude. Correlations between TLF and PLF yields are discussed.
The $^{136}$Xe + $^{208}$Pb reaction: A test of models of multi-nucleon transfer reactions
Barrett, J S; Loveland, W; Zhu, S; Ayangeakaa, A D; Carpenter, M P; Greene, J P; Janssens, R V F; Lauritsen, T; McCutchan, E A; Sonzogni, A A; Chiara, C J; Harker, J L; Walters, W B
2015-01-01T23:59:59.000Z
The yields of over 200 projectile-like fragments (PLFs) and target-like fragments (TLFs) from the interaction of (E$_{c.m.}$=450 MeV) $^{136}$Xe with a thick target of $^{208}$Pb were measured using Gammasphere and off-line $\\gamma$-ray spectroscopy, giving a comprehensive picture of the production cross sections in this reaction.The measured yields were compared to predictions of the GRAZING model and the predictions of Zagrebaev and Greiner using a quantitative metric, the theory evaluation factor, {\\bf tef}. The GRAZING model predictions are adequate for describing the yields of nuclei near the target or projectile but grossly underestimate the yields of all other products. The predictions of Zagrebaev and Greiner correctly describe the magnitude and maxima of the observed TLF transfer cross sections for a wide range of transfers ($\\Delta$Z = -8 to $\\Delta$Z = +2). However for $\\Delta$Z =+4, the observed position of the maximum in the distribution is four neutrons richer than the predicted maximum. The pre...
AN EXPERIMENTAL INVESTIGATION OF THE HEAT TRANSFER FROM A BUOYANT GAS PLUME TO A
Winfree, Erik
Temperature E. Heat Transfer Model 1. Determining the Ceiling Heat Transfer 2. Ceiling Heat Transfer
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhang, Le; Luo, Feng; Xu, Ruina; Jiang, Peixue; Liu, Huihai
2014-12-31T23:59:59.000Z
The heat transfer and fluid transport of supercritical CO2 in enhanced geothermal system (EGS) is studied numerically with local thermal non-equilibrium model, which accounts for the temperature difference between solid matrix and fluid components in porous media and uses two energy equations to describe heat transfer in the solid matrix and in the fluid, respectively. As compared with the previous results of our research group, the effect of local thermal non-equilibrium mainly depends on the volumetric heat transfer coefficient ah, which has a significant effect on the production temperature at reservoir outlet and thermal breakthrough time. The uniformity of volumetricmore »heat transfer coefficient ah has little influence on the thermal breakthrough time, but the temperature difference become more obvious with time after thermal breakthrough with this simulation model. The thermal breakthrough time reduces and the effect of local thermal non-equilibrium becomes significant with decreasing ah.« less
Entanglement Entropy from Corner Transfer Matrix in Forrester Baxter non-unitary RSOS models
Bianchini, Davide
2015-01-01T23:59:59.000Z
Using a Corner Transfer Matrix approach, we compute the bipartite entanglement R\\'enyi entropy in the off-critical perturbations of non-unitary conformal minimal models realised by lattice spin chains Hamiltonians related to the Forrester Baxter RSOS models in regime III. This allows to show on a set of explicit examples that the R\\'enyi entropies for non-unitary theories rescale near criticality as the logarithm of the correlation length with a coefficient proportional to the effective central charge. This complements a similar result, recently established for the size rescaling at the critical point, showing the expected agreement of the two behaviours. We also compute the first subleading unusual correction to the scaling behaviour, showing that it is expressible in terms of expansions of various fractional powers of the correlation length, related to the differences $\\Delta-\\Delta_{\\min}$ between the conformal dimensions of fields in the theory and the minimal conformal dimension. Finally, a few observati...
Cloudy Sky RRTM Shortwave Radiative Transfer and Comparison to the Revised ECMWF Shortwave Model
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41cloth Documentation DataDepartment of EnergyOn-Farm1CharacterizationIowaClimate, EarthClosestCloud-ResolvingR.
An Update on Radiative Transfer Model Development at Atmospheric and Environmental Research, Inc.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41cloth Documentation DataDepartment of EnergyOn-Farm Biofuelin HawaiiNaturalAdvanced Battery Manufacturing An|Update
Development and Evaluation of RRTMG_SW, a Shortwave Radiative Transfer Model for GCM Applications
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville Power Administration wouldDecember 2014Field Campaign: Potential ApplicationalbedoandDevelopment
Global oceanic rainfall estimation from AMSR-E data based on a radiative transfer model
Jin, Kyoung-Wook
2006-04-12T23:59:59.000Z
retrieval uncertainties. The algorithm uses six channels (dual polarizations at 36.5, 18.7 and 10.65GHz) and retrieves rain rates on a pixel-by-pixel basis. Monthly rain totals are estimated by summing average rain rates computed by merging six rain rates...
Macro-particle FEL model with self-consistent spontaneous radiation
Litvinenko, Vladimir N
2015-01-01T23:59:59.000Z
Spontaneous radiation plays an important role in SASE FELs and storage ring FELs operating in giant pulse mode. It defines the correlation function of the FEL radiation as well as its many spectral features. Simulations of these systems using randomly distributed macro-particles with charge much higher that of a single electron create the problem of anomalously strong spontaneous radiation, limiting the capabilities of many FEL codes. In this paper we present a self-consistent macro-particle model which provided statistically exact simulation of multi-mode, multi-harmonic and multi-frequency short-wavelength 3-D FELs including the high power and saturation effects. The use of macro-particle clones allows both spontaneous and induced radiation to be treated in the same fashion. Simulations using this model do not require a seed and provide complete temporal and spatial structure of the FEL optical field.
Radiative Reactions and Coherence Modeling in the High Altitude Electromagnetic Pulse
Charles N. Vittitoe; Mario Rabinowitz
2003-06-03T23:59:59.000Z
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.
Modeling of the radiation belt megnetosphere in decisional timeframes
Koller, Josef; Reeves, Geoffrey D; Friedel, Reiner H.W.
2013-04-23T23:59:59.000Z
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*.
To appear in ApJ, December 1, 2003 2-D Radiative Transfer in Protostellar Envelopes: II. An
Whitney, Barbara A.
, Berkeley, CA 94720; mco- hen@astro.berkeley.edu #12; 2 models with the same grain properties throughout
Quantum method of determination of penetrability in FRW model with radiation
Sergei P. Maydanyuk
2014-07-18T23:59:59.000Z
In paper the closed Friedmann-Robertson-Walker model with quantization in presence of the positive cosmological constant, radiation and Chaplygin gas is studied. For analysis of tunneling probability for birth of an asymptotically deSitter, inflationary Universe as a function of the radiation energy a new definition of a "free" wave propagating inside strong fields is introduced. Vilenkin's tunneling boundary condition is corrected, penetrability and reflection are calculated in fully quantum stationary approach.
The Radiative Properties of Small Clouds: Multi-Scale Observations and Modeling
Feingold, Graham [NOAA ESRL; McComiskey, Allison [CIRES, University of Colorado
2013-09-25T23:59:59.000Z
Warm, liquid clouds and their representation in climate models continue to represent one of the most significant unknowns in climate sensitivity and climate change. Our project combines ARM observations, LES modeling, and satellite imagery to characterize shallow clouds and the role of aerosol in modifying their radiative effects.
The 1D Iterative Model for Predicting Thermal Radiation from a Jet Fire
Paris-Sud XI, Université de
manuscript, published in "6. International Seminar on Fire and Explosion Hazards (FEH), Leeds : UnitedThe 1D Iterative Model for Predicting Thermal Radiation from a Jet Fire Leroy, G.* and Duplantier of the current jet fire models used in the accidental fire risks department are semi- empirical. They depend
A new one-dimensional radiative equilibrium model for investigating atmospheric
(s) into the building blocks of climate models seems necessary. The Earth system as a whole is virtually driven system 1. INTRODUCTION Climate models built on the principles of energy, momentum and mass balances have and maintained by the radiation exchange between the Earth system and space (e.g. Lesins 1990; Stephens & O
PROSPECT-4 and 5: Advances in the leaf optical properties model separating photosynthetic pigments
Gitelson, Anatoly
Ecology, Carnegie Institution of Washington, 260 Panama Street, Stanford, CA 94305, USA d Center reserved. Keywords: Leaf optical properties Radiative transfer model PROSPECT Hyperspectral data Pigments 1
Bordenave, Charles
Thesis proposal CSF Brazil 2014 Title: Modeling of water transfer and suspended sediments is to modeling water and sediment transport at the Amazon catchment scale. Investigations will consist storage and sediment deposition on scenario in a context of global changes. Subject description: spended
ON THE ROLE OF THERMOELECTRIC HEAT TRANSFER IN THE DESIGN OF SMA ACTUATORS: THEORETICAL MODELING theoretical/experimentalstudy of the heat transferin thermoelectricShape Memory Alloy (SMA) actuators is undertaken in this paper. A one-dimensional model of a thermoelectric unit cell with a SMA junction
Kansas, University of
. However, TCP connections may be running over a multilink connection that aggregates the bandwidth latency for a long transfer. The performance model is experimentally evaluated by running TCP over MLPPP connections is predicted using the proposed model by varying the call drop rate and the packet loss
Heat transfer pathways in underfloor air distribution (UFAD) systems
Bauman, F.; Jin, H.; Webster, T.
2006-01-01T23:59:59.000Z
radiative heat transfer, since radiation was neglectedradiation striking the floor makes up the majority of the total heat transferheat transfer processes: conduction through the slab and floor panels and into the supply plenum via convection; radiation
Bretherton, Chris
Evaluation of Clouds and Their Radiative Effects Simulated by the NCAR Community Atmospheric Model-4738 (Accepted) #12;1 ABSTRACT Cloud climatology and the cloud radiative forcing at the top cloud radiative forcing at the TOA at different latitudes. The differences of cloud vertical structures
Crisis of the Chaotic Attractor of a Climate Model: A Transfer Operator Approach
Alexis Tantet; Valerio Lucarini; Frank Lunkeit; Henk A. Dijkstra
2015-07-08T23:59:59.000Z
The destruction of a chaotic attractor leading to a rough change in the dynamics of a system as a control parameter is smoothly varied is studied. While bifurcations involving non-chaotic invariant sets, such as fixed points or periodic orbits, can be characterised by a Lyapunov exponent crossing the imaginary axis, little is known about the changes in a chaotic attractor during a crisis. The statistical physics framework, is particularly well suited for the study of global properties of chaotic systems. In particular, the semigroup of transfer operators governing the finite time evolution of probability distributions in phase space and its spectrum characterises both the relaxation rate of distributions to a statistical steady-state and the stability of this steady-state to perturbations. If critical slowing down indeed occurs in the approach to an attractor crisis, the gap in the spectrum (between the leading eigenvalue and the secondary ones) of the semigroup is expected to shrink. Here we use a high-dimensional, chaotic climate model system in which a transition from today's warm climate state to a snow-covered state occurs. This transition is associated with the destruction of a chaotic attractor as the solar constant is decreased. We show that critical slowing down develops in this model before the destruction of the chaotic attractor and that it can be observed from trajectories along the attractor. In addition, we demonstrate that the critical slowing down can be traced back to the shrinkage of the leading eigenvalues of coarse-grained approximations of the transfer operators and that these eigenvalues capture the fundamental features of the attractor crisis.
Computer simulation and topological modeling of radiation effects in zircon
Zhang, Yi, 1979-
2006-01-01T23:59:59.000Z
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 ...
Modeling progression in radiation-induced lung adenocarcinomas
Fakir, Hatim; Hofmann, Werner; Sachs, Rainer K.
2010-01-01T23:59:59.000Z
carrying capacity. Indeed, Speer et al. (1984) showed thatdata for tumor growth (Speer et al. 1984). In our study,model. Math Biosci Speer JF, Petrosky VE, Retsky MW,
The Accretion Wind Model of the Fermi Bubbles (II): Radiation
Mou, Guobin; Gan, Zhaoming; Sun, Mouyuan
2015-01-01T23:59:59.000Z
In a previous work, we have shown that the formation of the Fermi bubbles can be due to the interaction between winds launched from the hot accretion flow in Sgr A* and the interstellar medium (ISM). In that work, we focus only on the morphology. In this paper we continue our study by calculating the gamma-ray radiation. Some cosmic ray protons (CRp) and electrons must be contained in the winds, which are likely formed by physical processes such as magnetic reconnection. We have performed MHD simulations to study the spatial distribution of CRp, considering the advection and diffusion of CRp in the presence of magnetic field. We find that a permeated zone is formed just outside of the contact discontinuity between winds and ISM, where the collisions between CRp and thermal nuclei mainly occur. The decay of neutral pions generated in the collisions, combined with the inverse Compton scattering of background soft photons by the secondary leptons generated in the collisions and primary CR electrons can well expl...
A wave-mechanical model of incoherent neutron scattering II. Role of the momentum transfer
Frauenfelder, Hans; Fenimore, Paul W
2015-01-01T23:59:59.000Z
We recently introduced a wave-mechanical model for quasi-elastic neutron scattering (QENS) in proteins. We call the model ELM for "Energy Landscape Model". We postulate that the spectrum of the scattered neutrons consists of lines of natural width shifted from the center by fluctuations. ELM is based on two facts: Neutrons are wave packets; proteins have low-lying substates that form the free-energy landscape (FEL). Experiments suggest that the wave packets are a few hundred micrometers long. The interaction between the neutron and a proton in the protein takes place during the transit of the wave packet. The wave packet exerts the force $F(t) = dQ(t)/dt$ on the protein moiety, a part of the protein surrounding the struck proton. $Q(t)$ is the wave vector (momentum) transferred by the neutron wave packet to the proton during the transit. The ensuing energy is stored in the energy landscape and returned to the neutron as the wave packet exits. Kinetic energy thus is changed into potential energy and back. The ...
Reeves, Geoffrey D [Los Alamos National Laboratory; Friedel, Reiner H W [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory
2008-01-01T23:59:59.000Z
The Dynamic Radiation Environment Assimilation Model (DREAM) was developed at Los Alamos National Laboratory to assess, quantify, and predict the hazards from the natural space environment and the anthropogenic environment produced by high altitude nuclear explosions (HANE). DREAM was initially developed as a basic research activity to understand and predict the dynamics of the Earth's Van Allen radiation belts. It uses Kalman filter techniques to assimilate data from space environment instruments with a physics-based model of the radiation belts. DREAM can assimilate data from a variety of types of instruments and data with various levels of resolution and fidelity by assigning appropriate uncertainties to the observations. Data from any spacecraft orbit can be assimilated but DREAM was designed to function with as few as two spacecraft inputs: one from geosynchronous orbit and one from GPS orbit. With those inputs, DREAM can be used to predict the environment at any satellite in any orbit whether space environment data are available in those orbits or not. Even with very limited data input and relatively simple physics models, DREAM specifies the space environment in the radiation belts to a high level of accuracy. DREAM has been extensively tested and evaluated as we transition from research to operations. We report here on one set of test results in which we predict the environment in a highly-elliptical polar orbit. We also discuss long-duration reanalysis for spacecraft design, using DREAM for real-time operations, and prospects for 1-week forecasts of the radiation belt environment.
Volterra network modeling of the nonlinear finite-impulse reponse of the radiation belt flux
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
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.
Grant L. Hawkes; James E. O'Brien; Greg Tao
2011-11-01T23:59:59.000Z
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.
Rydberg, Bjorn; Cooper, Brian; Cooper, Priscilla K.; Holley, William; Chatterjee, Aloke
2004-01-01T23:59:59.000Z
S. Kim, and R. M. Myers. Radiation hybrid mapping: a somaticformulation of dual radiation action. Radiat. Res. 75: 471-High-Linear Energy Transfer Radiation in Human Fibroblasts.
Surussavadee, Chinnawat
2007-01-01T23:59:59.000Z
This thesis develops and validates the MM5/TBSCAT/F([lambda]) model, composed of a mesoscale numerical weather prediction (NWP) model (MM5), a two-stream radiative transfer model (TBSCAT), and electromagnetic models for ...
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
Thoughts on entropic gravity in the Parikh-Wilczek tunneling model of Hawking radiation
Wen-Yu Wen
2014-05-28T23:59:59.000Z
In this letter, we use the Parikh-Wilczek tunneling model of Hawking radiation to illustrate that a reformulation of Verlinde's entropic gravity is needed to derive the Newton's law for a temperature-varying screen, demanded by the conservation of energy. Furthermore, the entropy stored in the holographic screen is shown to be additive and its temperature dependence can be obtained.
Modeling proton intensity gradients and radiation dose equivalents in the inner
Pringle, James "Jamie"
Modeling proton intensity gradients and radiation dose equivalents in the inner heliosphere using exposure in IP space. In this paper, we utilize EMMREM to study the radial dependence of proton peak crossfield diffusion at large radial distances. Our results show that radial dependencies of proton peak
-mail: charles-alexis.asselineau@anu.edu.au 1. Introduction In concentrated solar power systems, receivers convert concentrated solar radiation into heat and, consequently, have a major impact on overall system modeling Charles-Alexis Asselineau1 , Jose Zapata1 and Dr John Pye1 1 Solar Thermal Group, College
Rabindra Nath Das
2007-01-16T23:59:59.000Z
The linear non homogeneous singular integral equation (LNSIE)derived from the nonlinear non homogeneous integral eauation (NNIE)of Chandrsasekhar's H- functions is considered here to develop a new form of H - functions.The Plemelj's formulae are applied to that equation to determine a new linear non homogeneous integral equation(LNIE)for H- functions in complex plane . The analytic properties of this new linear integral equation are assessed and compared with known linear integral equations satisfied by H- functions. The Cauchy integral formulae in complex plane are used to obtain this form of H- functions not dependent on H- function in the integral . This new form of H-function is represented as a simple integral in terms of known functions both for conservative and non conservative cases. This is identical with the form of H- functions derived by this author by application of Wiener HOpf technique. The equivalence of application of the theory of linear singular integral equation in Riemann Hilbert Problem and of the technique of Wiener- Hopf in linear integral in representing the H- functions is therefore eatablished .This new form may be used for solving the problems of radiative transfer in anisotropic and non coherent scattering by the method of Laplace Transform and Wiener -Hopf technique.
A Black-box Modelling Engine for Discharge Produced Plasma Radiation Sources
Zakharov, S.V.; Choi, P.; Krukovskiy, A.Y.; Zhang, Q. [EPPRA sas, 91961 Courtaboeuf (France); Novikov, V.G.; Zakharov, V.S. [KIAM RAS, 125047 Moscow (Russian Federation)
2006-01-05T23:59:59.000Z
A Blackbox Modelling Engine (BME), is an instrument based on the adaptation of the RMHD code Z*, integrated into a specific computation environment to provide a turn key simulation instrument and to enable routine plasma modelling without specialist knowledge in numerical computation. Two different operating modes are provided: Detailed Physics mode and Fast Numerics mode. In the Detailed Physics mode, non-stationary, non-equilibrium radiation physics have been introduced to allow the modelling of transient plasmas in experimental geometry. In the Fast Numerics mode, the system architecture and the radiation transport is simplified to significantly accelerate the computation rate. The Fast Numerics mode allows the BME to be used realistically in parametric scanning to explore complex physical set up, before using the Detailed Physics mode. As an example of the results from the BME modelling, the EUV source plasma dynamics in the pulsed capillary discharge are presented.
Gunner, Marilyn
Modeling the Effects of Mutations on the Free Energy of the First Electron Transfer from QA - to QB, 1999; ReVised Manuscript ReceiVed February 14, 2000 ABSTRACT: Numerical calculations of the free energy changes in nearby residues. This reduces the effect of mutation and makes the changes in state free energy
A WSRC-MS-g8-00318 Heat Transfer Model of Above and Underground...
Office of Scientific and Technical Information (OSTI)
of the surrounding air to prevent condensation. Most of city water, sewage and liquid waste are usually transferred through single or double underground pipe lines. The...
Heat and Mass Transfer Wrme-und Stoffbertragung
Guo, Zhixiong "James"
Transfer (2013) 49:405-412 DOI 10.1007/s00231-012-1077-8 Natural convection and radiation heat transfer 12 months after publication. #12;ORIGINAL Natural convection and radiation heat transfer wall temperature, both the natural convection and radiation heat transfer are enhanced
A wave-mechanical model of incoherent neutron scattering II. Role of the momentum transfer
Hans Frauenfelder; Robert D. Young; Paul W. Fenimore
2015-08-20T23:59:59.000Z
We recently introduced a wave-mechanical model for quasi-elastic neutron scattering (QENS) in proteins. We call the model ELM for "Energy Landscape Model". We postulate that the spectrum of the scattered neutrons consists of lines of natural width shifted from the center by fluctuations. ELM is based on two facts: Neutrons are wave packets; proteins have low-lying substates that form the free-energy landscape (FEL). Experiments suggest that the wave packets are a few hundred micrometers long. The interaction between the neutron and a proton in the protein takes place during the transit of the wave packet. The wave packet exerts the force $F(t) = dQ(t)/dt$ on the protein moiety, a part of the protein surrounding the struck proton. $Q(t)$ is the wave vector (momentum) transferred by the neutron wave packet to the proton during the transit. The ensuing energy is stored in the energy landscape and returned to the neutron as the wave packet exits. Kinetic energy thus is changed into potential energy and back. The interaction energy is proportional to $Q$, not to $Q^2$. To develop and check the ELM, we use published work on dehydrated proteins after reversing improper normalizations. In such proteins only vibrations are active and the effects caused by the neutron momentum can be studied undisturbed by external fluctuations. ELM has predictive power. For example it quantitatively predicts the observed inelastic incoherent fraction $S(Q, T)$ over a broad range of temperature and momentum $Q$ with one coefficient if $S(0, T)$ is known.
Cai, Yongxia; McCarl, Bruce A.
2007-01-01T23:59:59.000Z
). Models with economic considerations tend to cover only restricted areas, for example, the Edwards aquifer and Nueces, Frio and Guadalupe-Blanco basin regions (Gillig et al, 2001; Watkins Jr & McKinney, 2000). Much of the research has been localized... scarcity issues and socially optimal water allocation along with the effects of inter-basin water transfers. We developed an integrated economic, hydrologic, and environment model covering 21 Texas riverbasins: Colorado, Brazos-Colorado, Brazos, Brazos...
Modeling the efficiency of Frster resonant energy transfer from energy relay dyes in dye-
McGehee, Michael
resonant energy transfer can improve the spectral breadth, absorption and energy conversion efficiency of dye sensitized solar cells. In this design, unattached relay dyes absorb the high energy photons: (260.2160) Energy Transfer; (350.6050) Solar Energy; (160.2540) Fluorescent and luminescent materials
Gustavsen, Arild
2009-01-01T23:59:59.000Z
free convection. In: Heat Transfer and Turbulent Buoyantof convection heat transfer and develop correlations.and radiation heat transfer and develop correlations for
Harvesting nanoscale thermal radiation using pyroelectric materials
Fang, Jin; Frederich, Hugo; Pilon, Laurent
2010-01-01T23:59:59.000Z
the other hand, energy transfer by thermal radiation betweenit was shown that energy transfer by thermal radi- ationpyroelectric energy conversion and nanoscale thermal
A unified model for radiation-resistance of advanced space solar cells
Yamaguchi, Masafumi [Toyota Technical Inst., Nagoya (Japan); Katsumoto, Shingo [Univ. of Tokyo (Japan); Amano, Chikara [NTT Opto-Electrical Labs., Kanagawa (Japan)
1994-12-31T23:59:59.000Z
1-MeV electron irradiation effects on MBE-grown InGaAs and AlGaAs solar cells have been examined in comparison with previous results for radiation damage of InP and GaAs solar cells in order to clarify radiation-resistance of advanced space solar cells. Moreover, 1-MeV electron irradiation results of several space solar cells such as InP, InGaP, InGaAsP, GaAs, AlGaAs, InGaAs, Si, Ge, and CuInSe{sub 2} cells have also been analyzed by considering their damage constants, bandgap energies and optical absorption coefficients. The authors believe that this study will provide a unified model for radiation-resistance of advanced space solar cells.
Radiative reactions and coherence modeling in the high-altitude electromagnetic pulse
Vittitoe, C.N.; Rabinowitz, M.
1988-03-15T23:59:59.000Z
A high-altitude nuclear electromagnetic pulse (EMP) with a peak field intensity of 5 x 10/sup 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.
Dark radiation constraints on minicharged particles in models with a hidden photon
Vogel, Hendrik; Redondo, Javier, E-mail: hvogel@mpp.mpg.de, E-mail: redondo@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München (Germany)
2014-02-01T23:59:59.000Z
We compute the thermalization of a hidden sector consisting of minicharged fermions (MCPs) and massless hidden photons in the early Universe. The precise measurement of the anisotropies of the cosmic microwave background (CMB) by Planck and the relic abundance of light nuclei produced during big bang nucleosynthesis (BBN) constrain the amount of dark radiation of this hidden sector through the effective number of neutrino species, N{sub eff}. This study presents novel and accurate predictions of dark radiation in the strongly and weakly coupled regime for a wide range of model parameters. We give the value of N{sub eff} for MCP masses between ? 100 keV and 10 GeV and minicharges in the range 10{sup ?11}?1. Our results can be used to constrain MCPs with the current data and they are also a valuable indicator for future experimental searches, should the hint for dark radiation manifest itself in the next release of Planck's data.
Scanza, Rachel [Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences; Mahowald, N. [Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences; Ghan, Steven J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Div.; Zender, C. S. [Univ. of California, Irvine, CA (United States). Dept. of Earth Systems Science; Kok, J. F. [Univ. of California, Los Angeles, CA (United States). Dept. of Atmospheric and Oceanic Sciences; Liu, Xiaohong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Div.; Univ. of Wyoming, Laramie, WY (United States). Dept. of Atmospheric Science; Zhang, Y. [Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences; Fudan Univ., Shanghai (China). Dept. of Environmental Science and Engineering; Albani, Samuel [Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences
2015-01-01T23:59:59.000Z
The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale, using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral components in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as + 0.05 Wm?² for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm?²) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, -0.05 and -0.17 Wm?², respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Scanza, Rachel; Mahowald, N.; Ghan, Steven J.; Zender, C. S.; Kok, J. F.; Liu, Xiaohong; Zhang, Y.; Fudan Univ., Shanghai; Albani, Samuel
2015-01-01T23:59:59.000Z
The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale, using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral componentsmore »in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as + 0.05 Wm?² for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm?²) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, -0.05 and -0.17 Wm?², respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.« less
Dark radiation and dark matter in supersymmetric axion models with high reheating temperature
Graf, Peter; Steffen, Frank Daniel, E-mail: graf@mpp.mpg.de, E-mail: steffen@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, D–80805 Munich (Germany)
2013-12-01T23:59:59.000Z
Recent studies of the cosmic microwave background, large scale structure, and big bang nucleosynthesis (BBN) show trends towards extra radiation. Within the framework of supersymmetric hadronic axion models, we explore two high-reheating-temperature scenarios that can explain consistently extra radiation and cold dark matter (CDM), with the latter residing either in gravitinos or in axions. In the gravitino CDM case, axions from decays of thermal saxions provide extra radiation already prior to BBN and decays of axinos with a cosmologically required TeV-scale mass can produce extra entropy. In the axion CDM case, cosmological constraints are respected with light eV-scale axinos and weak-scale gravitinos that decay into axions and axinos. These decays lead to late extra radiation which can coexist with the early contributions from saxion decays. Recent results of the Planck satellite probe extra radiation at late times and thereby both scenarios. Further tests are the searches for axions at ADMX and for supersymmetric particles at the LHC.
Li, Zhiyong; Chen, Chao; Luo, Hailiang; Zhang, Ye; Xue, Yaning [College of Architecture and Civil Engineering, Beijing University of Technology, Beijing (China)
2010-08-15T23:59:59.000Z
The aim of this paper is to establish the heat transfer model of all-glass vacuum tube collector used in forced-circulation solar water heating system. In this model, the simplified heat transfer of collector is composed of the natural convection in single glass tube and forced flow in manifold header. Thus the heat balance equation of water in single tube and the heat balance equation of water in manifold header have been established. The flow equation is also built by analyzing the friction and buoyancy in tube. Through solved these equations the relationship between the collector average temperature, the outlet temperature and natural convection flow rate have been obtained. From this relationship and energy balance equation of collector, the collector outlet temperature can be calculated. The validated experiments of this model were carried out in winter of Beijing. (author)
Gustavsen, Arlid
2008-01-01T23:59:59.000Z
be used to calculate radiation heat transfer. The convectionat about 5×10 -10 ). Radiation heat transfer was included inof rays in the radiation heat-transfer algorithm of the CFD
Collisional-radiative modeling of tungsten at temperatures of 1200–2400 eV
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Colgan, James; Fontes, Christopher; Zhang, Honglin; Abdallah, Jr., Joseph
2015-04-30T23:59:59.000Z
We discuss new collisional-radiative modeling calculations of tungsten at moderate temperatures of 1200 to 2400 eV. Such plasma conditions are relevant to ongoing experimental work at ASDEX Upgrade and are expected to be relevant for ITER. Our calculations are made using the Los Alamos National Laboratory (LANL) collisional-radiative modeling ATOMIC code. These calculations formed part of a submission to the recent NLTE-8 workshop that was held in November 2013. This series of workshops provides a forum for detailed comparison of plasma and spectral quantities from NLTE collisional-radiative modeling codes. We focus on the LANL ATOMIC calculations for tungsten that weremore »submitted to the NLTE-8 workshop and discuss different models that were constructed to predict the tungsten emission. In particular, we discuss comparisons between semi-relativistic configuration-average and fully relativistic configuration-average calculations. We also present semi-relativistic calculations that include fine-structure detail, and discuss the difficult problem of ensuring completeness with respect to the number of configurations included in a CR calculation.« less
V. Skalsky
2000-09-25T23:59:59.000Z
The present temperature of cosmic background radiation and the present number density of photons of cosmic background radiation in the observed expansive and isotropic relativistic Universe is in the standard model of universe explained by the assumption of emergence of the photons of cosmic background radiation on the horizon (of the most remote visibility). However, the physical analysis shows unambiguously that this assumption contradicts the special theory of relativity and the quantum mechanics.
A Parameterized Microwace Emission Model for Dry Snow Cover Lingmei JIANG1,2,3
California at Santa Barbara, University of
, and the measurements can be carried out through cloud cover. When snow starts to melt, emission will significantly the vector radiative transfer equations to include the multi-scattering effects. This model uses 1) the dense the Dense Media Radiative Transfer Model (DMRT) and AIEM to simulation of dry snow emission with Matrix
Viscous boundary layers of radiation-dominated, relativistic jets. I. The two-stream model
Coughlin, Eric R
2015-01-01T23:59:59.000Z
Using the relativistic equations of radiation hydrodynamics in the viscous limit, we analyze the boundary layers that develop between radiation-dominated jets and their environments. In this paper we present the solution for the self-similar, 2-D, plane-parallel two-stream problem, wherein the jet and the ambient medium are considered to be separate, interacting fluids, and we compare our results to those of previous authors. (In a companion paper we investigate an alternative scenario, known as the free-streaming jet model.) Consistent with past findings, we show that the boundary layer that develops between the jet and its surroundings creates a region of low-density material. These models may be applicable to sources such as super-Eddington tidal disruption events and long gamma-ray bursts.
THE FURNACE COMBUSTION AND RADIATION CHARACTERISTICS OF METHANOL AND A METHANOL/COAL SLURRY
Grosshandler, W.L.
2010-01-01T23:59:59.000Z
the structure and radiation heat transfer in a pure methanolHowell, Thermal Radiation Heat Transfer, McGraw-Hill Bookof in- creased radiation heat transfer from the flame zone
Winters, W.S.
1984-01-01T23:59:59.000Z
An overview of the computer code TOPAZ (Transient-One-Dimensional Pipe Flow Analyzer) is presented. TOPAZ models the flow of compressible and incompressible fluids through complex and arbitrary arrangements of pipes, valves, flow branches and vessels. Heat transfer to and from the fluid containment structures (i.e. vessel and pipe walls) can also be modeled. This document includes discussions of the fluid flow equations and containment heat conduction equations. The modeling philosophy, numerical integration technique, code architecture, and methods for generating the computational mesh are also discussed.
Kiryukhin, A.V.; Sugrobov, V.M.
1986-01-21T23:59:59.000Z
The application of the two-dimensional numerical heat-transfer model to the Pauzhetka hydrothermal system allowed us to establish that: (1) a shallow magma body with the anomalous temperature of 700-1000 C and with a volume of 20-30 km{sup 3} may be a heat source for the formation of the Pauzhetka hydrothermal system. (2) The water feeding source of the Pauzhetka hydrothermal system may be meteoric waters which are infiltrated at an average rate of 5-10 kg/s {center_dot} km{sup 2}. The coupling of the numerical heat-transfer model with hydroisotopic data (D,T,{sup 18}O) obtained from the results of testing of exploitation wells, rivers and springs is the basis to understand more clearly the position of recharge areas and the structure of water flows in the hydrothermal system.
MODELING THE DYNAMICAL COUPLING OF SOLAR CONVECTION WITH THE RADIATIVE INTERIOR
Brun, Allan Sacha [Laboratoire AIM Paris-Saclay, CEA/Irfu Universite Paris-Diderot CNRS/INSU, 91191 Gif-sur-Yvette (France); Miesch, Mark S. [High Altitude Observatory, NCAR, Boulder, CO 80307-3000 (United States); Toomre, Juri [JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309-0440 (United States)
2011-12-01T23:59:59.000Z
The global dynamics of a rotating star like the Sun involves the coupling of a highly turbulent convective envelope overlying a seemingly benign radiative interior. We use the anelastic spherical harmonic code to develop a new class of three-dimensional models that nonlinearly couple the convective envelope to a deep stable radiative interior. The numerical simulation assumes a realistic solar stratification from r = 0.07 up to 0.97R (with R the solar radius), thus encompassing part of the nuclear core up through most of the convection zone. We find that a tachocline naturally establishes itself between the differentially rotating convective envelope and the solid body rotation of the interior, with a slow spreading that is here diffusively controlled. The rapid angular momentum redistribution in the convective envelope leads to a fast equator and slow poles, with a conical differential rotation achieved at mid-latitudes, much as has been deduced by helioseismology. The convective motions are able to overshoot downward about 0.04R into the radiative interior. However, the convective meridional circulation there is confined to a smaller penetration depth and is directed mostly equatorward at the base of the convection zone. Thermal wind balance is established in the lower convection zone and tachocline but departures are evident in the upper convection zone. Internal gravity waves are excited by the convective overshooting, yielding a complex wave field throughout the radiative interior.
ME 544 Advanced Heat Transfer Spring 2013 Time: 2pm-3pm MWF
Connors, Daniel A.
and engineering applications of heat transfer including conduction, convection, and radiation. Course Learning, convection, and radiation heat transfer modes. 2. Determine the dominant modes of heat transfer, and apply fields. The last part of the course is concerned with radiation heat transfer, specifically radiation
Eltahir, Elfatih A. B.
A climate model must include an accurate surface physics scheme in order to examine the interactions between the land and atmosphere. Given an increase in the surface radiative forcing, the sensitivity of latent heat flux ...
Ostrovskaya, Natela Grigoryevna
2006-10-30T23:59:59.000Z
Lack of accurate data for epidemiological studies of low dose radiation effects necessitates development of dosimetric models allowing prediction of cancer risks for different organs. The objective of this work is to develop ...
Modelling for post-dryout heat transfer and droplet sizes at low pressure and low flow conditions
Jeong, H.Y.; No, H.C. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Nuclear Engineering] [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Nuclear Engineering
1996-10-01T23:59:59.000Z
A correlation describing the initial droplet size just after the CHF position at low mass flux is suggested through regression analysis. The history-dependent post-dryout model of Varone and Rohsenow replaced by the Webb-Chen model for wall-vapor heat transfer is used as a reference model in the analysis. In the post-dryout region at low pressure and low flow, it is found that the suggested one-dimensional mechanistic model is valid only in the churn-turbulent flow regime (j*{sub g} = 0.5 {approximately} 4.5). It is also suggested that the droplet size generated from the churn-turbulent surface is dependent not only on the pressure but also on the vapor velocity. It turns out that the present model can predict the measured cladding and vapor temperatures within 20% and 15%, respectively.
Tucker, Susan L., E-mail: sltucker@mdanderson.org [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li Minghuan [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China)] [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Xu Ting; Gomez, Daniel [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Yuan Xianglin [Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China)] [Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Yu Jinming [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China)] [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Liu Zhensheng; Yin Ming; Guan Xiaoxiang; Wang Lie; Wei Qingyi [Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Vinogradskiy, Yevgeniy [University of Colorado School of Medicine, Aurora, Colorado (United States)] [University of Colorado School of Medicine, Aurora, Colorado (United States); Martel, Mary [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)
2013-01-01T23:59:59.000Z
Purpose: To determine whether single-nucleotide polymorphisms (SNPs) in genes associated with DNA repair, cell cycle, transforming growth factor-{beta}, tumor necrosis factor and receptor, folic acid metabolism, and angiogenesis can significantly improve the fit of the Lyman-Kutcher-Burman (LKB) normal-tissue complication probability (NTCP) model of radiation pneumonitis (RP) risk among patients with non-small cell lung cancer (NSCLC). Methods and Materials: Sixteen SNPs from 10 different genes (XRCC1, XRCC3, APEX1, MDM2, TGF{beta}, TNF{alpha}, TNFR, MTHFR, MTRR, and VEGF) were genotyped in 141 NSCLC patients treated with definitive radiation therapy, with or without chemotherapy. The LKB model was used to estimate the risk of severe (grade {>=}3) RP as a function of mean lung dose (MLD), with SNPs and patient smoking status incorporated into the model as dose-modifying factors. Multivariate analyses were performed by adding significant factors to the MLD model in a forward stepwise procedure, with significance assessed using the likelihood-ratio test. Bootstrap analyses were used to assess the reproducibility of results under variations in the data. Results: Five SNPs were selected for inclusion in the multivariate NTCP model based on MLD alone. SNPs associated with an increased risk of severe RP were in genes for TGF{beta}, VEGF, TNF{alpha}, XRCC1 and APEX1. With smoking status included in the multivariate model, the SNPs significantly associated with increased risk of RP were in genes for TGF{beta}, VEGF, and XRCC3. Bootstrap analyses selected a median of 4 SNPs per model fit, with the 6 genes listed above selected most often. Conclusions: This study provides evidence that SNPs can significantly improve the predictive ability of the Lyman MLD model. With a small number of SNPs, it was possible to distinguish cohorts with >50% risk vs <10% risk of RP when they were exposed to high MLDs.
Power transfer through strongly coupled resonances
Kurs, André
2007-01-01T23:59:59.000Z
Using self-resonant coils in a strongly coupled regime, we experimentally demonstrate efficient non-radiative power transfer over distances of up to eight times the radius of the coils. We use this system to transfer 60W ...
Mork, B; Nelson, R; Kirkendall, B; Stenvig, N
2009-11-30T23:59:59.000Z
Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.
Vasilyev, Oleg V.
HTDVol.335, Proceedings of hte ASME Heat Transfer Division Volume 4 ASME 1996 THERMOACOUSTIC WAVE ABSTRACT Thermoacoustic wave propagation in a twodimensional rectan gular cavity is studied numerically. The thermoacoustic waves are generated by raising the temperature locally at the walls. The waves, which decay
Final Report - Epigenetics of low dose radiation effects in an animal model
Kovalchuk, Olga
2014-10-22T23:59:59.000Z
This project sought mechanistic understanding of the epigenetic response of tissues as well as the consequences of those responses, when induced by low dose irradiation in a well-established model system (mouse). Based on solid and extensive preliminary data we investigated the molecular epigenetic mechanisms of in vivo radiation responses, particularly – effects of low, occupationally relevant radiation exposures on the genome stability and adaptive response in mammalian tissues and organisms. We accumulated evidence that low dose irradiation altered epigenetic profiles and impacted radiation target organs of the exposed animals. The main long-term goal was to dissect the epigenetic basis of induction of the low dose radiation-induced genome instability and adaptive response and the specific fundamental roles of epigenetic changes (i.e. DNA methylation, histone modifications and miRNAs) in their generation. We hypothesized that changes in global and regional DNA methylation, global histone modifications and regulatory microRNAs played pivotal roles in the generation and maintenance low-dose radiation-induced genome instability and adaptive response. We predicted that epigenetic changes influenced the levels of genetic rearrangements (transposone reactivation). We hypothesized that epigenetic responses from low dose irradiation were dependent on exposure regimes, and would be greatest when organisms are exposed in a protracted/fractionated manner: fractionated exposures > acute exposures. We anticipated that the epigenetic responses were correlated with the gene expression levels. Our immediate objectives were: • To investigate the exact nature of the global and locus-specific DNA methylation changes in the LDR exposed cells and tissues and dissect their roles in adaptive response • To investigate the roles of histone modifications in the low dose radiation effects and adaptive response • To dissect the roles of regulatory microRNAs and their targets in low dose radiation effects and adaptive response • To correlate the levels of epigenetic changes with genetic rearrangement levels and gene expression patterns. In sum, we determined the precise global and locus-specific DNA methylation patterns in the LDR-exposed cells and tissues of mice, and to correlated DNA methylation changes with the gene expression patterns and manifestations of genome instability. We also determined the alterations of global histone modification pattern in the LDR exposed tissues. Additionally, we established the nature of microRNAome changes in the LDR exposed tissue. In this study we for the first time found that LDR exposure caused profound tissue-specific epigenetic changes in the exposed tissues. We established that LDR exposure affect methylation of repetitive elements in the murine genome, causes changes in histone methylation, acetylation and phosphorylation. Importantly, we found that LDR causes profound and persistent effects on small RNA profiles and gene expression, and that miRNAs are excellent biomarkers of LDR exposure. Furthermore, we extended our analysis and studied LDR effects in rat tissues and human tissues and cell lines. There we also analyzed LDR-induced gene expression, DNA methylation and miRNA changes. Our datasets laid foundation for several new research projects aimed to understand molecular underpinnings of low dose radiation responses, and biological repercussions of low dose radiation effects and radiation carcinogenesis.
Rich, P.M.; Hetrick, W.A.; Saving, S.C.
1994-12-31T23:59:59.000Z
This report is comprised of two studies. The first study focuses on plant canopies in pinyon-juniper woodland, ponderosa pine woodland, and waste sites at Los Alamos National Laboratory which involved five basic areas of research: (1) application of hemispherical photography and other gap fraction techniques to study solar radiation regimes and canopy architecture, coupled with application of time-domain reflectometry to study soil moisture; (2) detailed characterization of canopy architecture using stand mapping and allometry; (3) development of an integrated geographical information system (GIS) database for relating canopy architecture with ecological, hydrological, and system modeling approaches; (4) development of geometric models that simulate complex sky obstruction, incoming solar radiation for complex topographic surfaces, and the coupling of incoming solar radiation with energy and water balance, with simulations of incoming solar radiation for selected native vegetation and experimental waste cover design sites; and (5) evaluation of the strengths and limitations of the various field sampling techniques. The second study describes an approach to develop software that takes advantage of new generation computers to model insolation on complex topographic surfaces. SOLARFLUX is a GIS-based (ARC/INFO, GRID) computer program 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. This manual serves as the comprehensive guide to SOLARFLUX. Included are discussions on modelling insolation on complex surfaces, the theoretical approach, program setup and operation, and a set of applications illustrating characteristics of topographic insolation modelling.
Recent Heat Transfer Improvements to the RELAP5-3D Code
Riemke, Richard A; Davis, Cliff B; Oh, Chang
2007-05-01T23:59:59.000Z
The heat transfer section of the RELAP5-3D computer program has been recently improved. The improvements are as follows: (1) the general cladding rupture model was modified (more than one heat structure segment connected to the hydrodynamic volume and heat structure geometry’s internal gap pressure), (2) the cladding rupture model was modified for reflood, and (3) the heat transfer minor edits/plots were extended to include radiation/enclosure heat flux and generation (internal heat source).
Heat transfer pathways in underfloor air distribution (UFAD) systems
Bauman, F.; Jin, H.; Webster, T.
2006-01-01T23:59:59.000Z
is little radiative heat transfer and little impact on thereturn air extrac- tion and heat transfer to the plenum. ItUFAD is often used and heat transfer out of the room through
Modeling the comfort effects of short-wave solar radiation indoors
Arens, Edward; Huang, Li; Hoyt, Tyler; Zhou, Xin; Schiavon, Stefano
2014-01-01T23:59:59.000Z
effects of short-wave solar radiation indoors. Building andEFFECTS OF SHORT-WAVE SOLAR RADIATION INDOORS Edward ARENSK. The effects of solar radiation on thermal comfort.
Nottrott, A.; Onomura, S.; Inagaki, A.; Kanda, M.; Kleissl, J.
2011-01-01T23:59:59.000Z
Vortex structure and heat transfer in turbulent flow over asurface, Proc. 5 th Int. Heat Transfer Conf. 3 (1974) 129-a vertical plate, J. Heat Transfer 109(1) [13] K. Patel,
Appelt, Ane L., E-mail: ane.lindegaard.appelt@slb.regionsyddanmark.dk [Department of Oncology, Vejle Hospital, Vejle (Denmark); University of Southern Denmark, Odense (Denmark); Ploen, John [Department of Oncology, Vejle Hospital, Vejle (Denmark)] [Department of Oncology, Vejle Hospital, Vejle (Denmark); Vogelius, Ivan R. [Department of Radiation Oncology, Rigshospitalet, University of Copenhagen (Denmark)] [Department of Radiation Oncology, Rigshospitalet, University of Copenhagen (Denmark); Bentzen, Soren M. [Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin (United States)] [Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin (United States); Jakobsen, Anders [Department of Oncology, Vejle Hospital, Vejle (Denmark) [Department of Oncology, Vejle Hospital, Vejle (Denmark); University of Southern Denmark, Odense (Denmark)
2013-01-01T23:59:59.000Z
Purpose: Preoperative chemoradiation therapy (CRT) is part of the standard treatment of locally advanced rectal cancers. Tumor regression at the time of operation is desirable, but not much is known about the relationship between radiation dose and tumor regression. In the present study we estimated radiation dose-response curves for various grades of tumor regression after preoperative CRT. Methods and Materials: A total of 222 patients, treated with consistent chemotherapy and radiation therapy techniques, were considered for the analysis. Radiation therapy consisted of a combination of external-beam radiation therapy and brachytherapy. Response at the time of operation was evaluated from the histopathologic specimen and graded on a 5-point scale (TRG1-5). The probability of achieving complete, major, and partial response was analyzed by ordinal logistic regression, and the effect of including clinical parameters in the model was examined. The radiation dose-response relationship for a specific grade of histopathologic tumor regression was parameterized in terms of the dose required for 50% response, D{sub 50,i}, and the normalized dose-response gradient, {gamma}{sub 50,i}. Results: A highly significant dose-response relationship was found (P=.002). For complete response (TRG1), the dose-response parameters were D{sub 50,TRG1} = 92.0 Gy (95% confidence interval [CI] 79.3-144.9 Gy), {gamma}{sub 50,TRG1} = 0.982 (CI 0.533-1.429), and for major response (TRG1-2) D{sub 50,TRG1} and {sub 2} = 72.1 Gy (CI 65.3-94.0 Gy), {gamma}{sub 50,TRG1} and {sub 2} = 0.770 (CI 0.338-1.201). Tumor size and N category both had a significant effect on the dose-response relationships. Conclusions: This study demonstrated a significant dose-response relationship for tumor regression after preoperative CRT for locally advanced rectal cancer for tumor dose levels in the range of 50.4-70 Gy, which is higher than the dose range usually considered.
Time-dependent modeling of radiative processes in hot magnetized plasmas
Indrek Vurm; Juri Poutanen
2009-03-03T23:59:59.000Z
Numerical simulations of radiative processes in magnetized compact sources such as hot accretion disks around black holes, relativistic jets in active galaxies and gamma-ray bursts are complicated because the particle and photon distributions span many orders of magnitude in energy, they also strongly depend on each other, the radiative processes behave significantly differently depending on the energy regime, and finally due to the enormous difference in the time-scales of the processes. We have developed a novel computer code for the time-dependent simulations that overcomes these problems. The processes taken into account are Compton scattering, electron-positron pair production and annihilation, Coulomb scattering as well as synchrotron emission and absorption. No approximation has been made on the corresponding rates. For the first time, we solve coupled integro-differential kinetic equations for photons and electrons/positrons without any limitations on the photon and lepton energies. A numerical scheme is proposed to guarantee energy conservation when dealing with synchrotron processes in electron and photon equations. We apply the code to model non-thermal pair cascades in the blackbody radiation field, to study the synchrotron self-absorption as particle thermalization mechanism, and to simulate time evolution of stochastically heated pairs and corresponding synchrotron self-Compton photon spectra which might be responsible for the prompt emission of gamma-ray bursts. Good agreement with previous works is found in the parameter regimes where comparison is feasible, with the differences attributable to our improved treatment of the microphysics.
interior surface of the cavity is the focus of the incident concentrated solar radiation, and is compose. INTRODUCTION The Compact Linear Fresnel Reflector (CLFR) is a design concept for low -cost collection of solar Renewable Energy Targets of the State government. These Targets require power generators to produce 2
SU(5) Completion of the Dark Scalar Doublet Model of Radiative Neutrino Mass
Ernest Ma
2007-10-11T23:59:59.000Z
Adding a second scalar doublet (eta^+,eta^0) and three neutral singlet fermions N_{1,2,3} to the Standard Model of particle interactions with a new Z_2 symmetry, it has been shown that eta^0_R or eta^0_I is a good dark-matter candidate and seesaw neutrino masses are generated radiatively. A minimal extension of this new idea is proposed to allow for its SU(5) completion. Supersymmetric unification is then possible, and leptoquarks of a special kind are predicted at the TeV scale.
Evolution of Meteorological Base Models for Estimating Hourly Global Solar Radiation in Texas
Kim, H.; Baltazar, J.C.; Haberl, J.S
ESL-PA-13-11-01 Available online at www.sciencedirect.com Energy Procedia 00 (2013) 000–000 www.elsevier.com/locate/procedia 2013 ISES Solar World Congress Evaluation of Meteorological Base Models... for Estimating Hourly Global Solar Radiation in Texas Kee Han Kima,b*, Juan-Carlos Baltazarb, and Jeff S. Haberla,b aDepartment of Architecture, Texas A&M University, 3137 TAMU, College Station, TX 77843-3137, U.S.A. bEnergy Systems Laboratory, Texas A...
A revised model of the kidney for medical internal radiation dose calculations
Patel, Jyoti Shivabhai
1988-01-01T23:59:59.000Z
) G. A. Schlapper (Member) D. 'ghtower (Member) M. E. cLain (Member) ohn . Poston (Head of Department) December 1988 ABSTRACT A Revised Model of the Kidney for Medical Internal Radiation Dose. (December 1988) Jyoti Shivabhai Patel, B. A... it as their ultimate goal. ACKNOWLEDGEMENTS I would like to thank the members of my graduate committee, Dr. G. A. Schlapper, Dr. M. E. McLain, and Dr. D. Hightower. I would like to give special recognition to the committee chairman Dr. J. W. Poston for suggesting...
Wireless transfer of electric power
Moffatt, Robert Alexander
2009-01-01T23:59:59.000Z
In this dissertation, I describe the design and construction of a system which can transfer electric power wirelessly. This is accomplished using inductive, near-field, non-radiative coupling between self-resonant copper ...
Polarization of high-energy pulsar radiation in the striped wind model
J. Petri; J. Kirk
2005-05-20T23:59:59.000Z
The Stokes parameters of the pulsed synchrotron radiation produced in the striped pulsar wind model are computed and compared with optical observations of the Crab pulsar. We assume the main contribution to the wind emissivity comes from a thin transition layer where the dominant toroidal magnetic field reverses its polarity. The radial component of the field is neglected, but a small meridional component is added. The resulting radiation is linearly polarized (Stokes V=0). In the off-pulse region, the electric vector lies in the direction of the projection on the sky of the rotation axis of the pulsar. This property is unique to the wind model and in good agreement with the data. Other properties such as a reduced degree of polarization and a characteristic sweep of the polarization angle within the pulses are also reproduced. These properties are qualitatively unaffected by variations of the wind Lorentz factor, the electron injection power law index and the inclination of the line of sight.
Validated Models for Radiation Response and Signal Generation in Scintillators: Final Report
Kerisit, Sebastien N.; Gao, Fei; Xie, YuLong; Campbell, Luke W.; Van Ginhoven, Renee M.; Wang, Zhiguo; Prange, Micah P.; Wu, Dangxin
2014-12-01T23:59:59.000Z
This Final Report presents work carried out at Pacific Northwest National Laboratory (PNNL) under the project entitled “Validated Models for Radiation Response and Signal Generation in Scintillators” (Project number: PL10-Scin-theor-PD2Jf) and led by Drs. Fei Gao and Sebastien N. Kerisit. This project was divided into four tasks: 1) Electronic response functions (ab initio data model) 2) Electron-hole yield, variance, and spatial distribution 3) Ab initio calculations of information carrier properties 4) Transport of electron-hole pairs and scintillation efficiency Detailed information on the results obtained in each of the four tasks is provided in this Final Report. Furthermore, published peer-reviewed articles based on the work carried under this project are included in Appendix. This work was supported by the National Nuclear Security Administration, Office of Nuclear Nonproliferation Research and Development (DNN R&D/NA-22), of the U.S. Department of Energy (DOE).
Motta, Arthur T.
CHARACTERIZATION OF OXIDES FORMED ON MODEL ZIRCONIUM ALLOYS IN 360°C WATER USING MICRO National Laboratory, Argonne, IL, 60439, USA Keywords: Zirconium alloys, oxides, synchrotron radiation cycle applications. To undertake such research, model zirconium alloys (Zr-xCr-yFe, Zr-xCu-yMo, Zr
Kim, Young-Do; Lee, Hyo-Chang; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)] [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)
2013-09-15T23:59:59.000Z
Correlations between the external discharge parameters (the driving frequency ? and the chamber dimension R) and plasma characteristics (the skin depth ? and the electron-neutral collision frequency ?{sub m}) are studied using the transformer circuit model [R. B. Piejak et al., Plasma Sources Sci. Technol. 1, 179 (1992)] when the absorbed power is maximized in an inductively coupled plasma. From the analysis of the transformer circuit model, the maximum power transfer conditions, which depend on the external discharge parameters and the internal plasma characteristics, were obtained. It was found that a maximum power transfer occurs when ??0.38R for the discharge condition at which ?{sub m}/??1, while it occurs when ???(2)?(?/?{sub m})R for the discharge condition at which ?{sub m}/??1. The results of this circuit analysis are consistent with the stable last inductive mode region of an inductive-to-capacitive mode transition [Lee and Chung, Phys. Plasmas 13, 063510 (2006)], which was theoretically derived from Maxwell's equations. Our results were also in agreement with the experimental results. From this work, we demonstrate that a simple circuit analysis can be applied to explain complex physical phenomena to a certain extent.
Analysis and behavioral modeling of the Finite State Machines of the Xpress Transfer Protocol
Madduri, Venkateswara Rao
1994-01-01T23:59:59.000Z
. This research focuses on the analysis and behavioral modeling of the Finite State Machines of the XTP. The simulation language used is the Verilog Hardware Description Language. We have modeled XTP Finite State Machines as a set of communicating, concurrent...
On the spontaneous emission of electromagnetic radiation in the CSL model
Donadi, Sandro, E-mail: sandro.donadi@ts.infn.it [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy) [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy); Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste (Italy); Deckert, Dirk-André, E-mail: deckert@math.ucdavis.edu [Department of Mathematics, University of California, One Shields Ave, 95616 Davis (United States)] [Department of Mathematics, University of California, One Shields Ave, 95616 Davis (United States); Bassi, Angelo, E-mail: bassi@ts.infn.it [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy) [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy); Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste (Italy)
2014-01-15T23:59:59.000Z
Spontaneous photon emission in the Continuous Spontaneous Localization (CSL) model is studied one more time. In the CSL model each particle interacts with a noise field that induces the collapse of its wave function. As a consequence of this interaction, when the particle is electrically charged, it radiates. As discussed in Adler (2013) the formula for the emission rate, to first perturbative order, contains two terms: one is proportional to the Fourier component of the noise field at the same frequency as that of the emitted photon and one is proportional to the zero Fourier component of the noise field. As discussed in previous works, this second term seems unphysical. In Adler (2013) it was shown that the unphysical term disappears when the noise is confined to a bounded region and the final particle’s state is a wave packet. Here we investigate the origin of this unphysical term and why it vanishes according to the previous prescription. We will see that perturbation theory is formally not valid in the large time limit since the effect of the noise accumulates continuously in time. Therefore either one performs an exact calculation (or at least in some way includes higher order terms) as we do here, or one finds a way to make a perturbative calculation meaningful, e.g., by confining the system as in Adler (2013). -- Highlights: •We compute the electromagnetic radiation emission in collapse models. •Under only the dipole approximation, the equations of motion are solved exactly. •The electromagnetic interaction must be treated exactly. •In order to obtain the correct emission rate the particle must be bounded.
Ren, Kui
-performance semiconductor-liquid junction solar cells. We propose in this work a macroscopic mathematical model, a sys- tem-liquid junction, solar cell simulation, naso-scale device modeling. 1 Introduction The mathematical modeling by the increasing need of simulation tools for designing efficient solar cells to harvest sunlight for clean energy
Micro/Nanoscale Heat Transfer: Interfacial Effects Dominate the
Kostic, Milivoje M.
conduction 2. Convective heat transfer 3. Thermal radiation 4. Conclusions 1.1 Thermal conductivity3/15/2012 1 Micro/Nanoscale Heat Transfer: Interfacial Effects Dominate the Heat Transfer 1 Xing/nanoscale heat transfer becomes critical. What is the dominant factor in micro/nanosclae heat transfer
Ivanov, Michael A Liberman M F
2015-01-01T23:59:59.000Z
We examines regimes of the hydrogen flames propagation and ignition of mixtures heated by the radiation emitted from the flame. The gaseous phase is assumed to be transparent for radiation, while the suspended particles of the dust cloud ahead of the flame absorb and reemit the radiation. The radiant heat absorbed by the particles is then lost by conduction to the surrounding unreacted gaseous phase so that the gas phase temperature lags that of the particles. The direct numerical simulations solve the full system of two phase gas dynamic time-dependent equations with a detailed chemical kinetics for a plane flames propagating through a dust cloud. Depending on the spatial distribution of the dispersed particles and on the value of radiation absorption length the consequence of the radiative preheating of the unreacted mixture can be either the increase of the flame velocity for uniformly dispersed particles or ignition deflagration or detonation ahead of the flame via the Zel'dovich gradient mechanism in the...
Xiao, Heng; Gustafson, William I.; Wang, Hailong
2014-04-29T23:59:59.000Z
Subgrid-scale interactions between turbulence and radiation are potentially important for accurately reproducing marine low clouds in climate models. To better understand the impact of these interactions, the Weather Research and Forecasting (WRF) model is configured for large eddy simulation (LES) to study the stratocumulus-to-trade cumulus (Sc-to-Cu) transition. Using the GEWEX Atmospheric System Studies (GASS) composite Lagrangian transition case and the Atlantic Trade Wind Experiment (ATEX) case, it is shown that the lack of subgrid-scale turbulence-radiation interaction, as is the case in current generation climate models, accelerates the Sc-to-Cu transition. Our analysis suggests that in cloud-topped boundary layers subgrid-scale turbulence-radiation interactions contribute to stronger production of temperature variance, which in turn leads to stronger buoyancy production of turbulent kinetic energy and helps to maintain the Sc cover.
Medina, M. A.
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...
Radiation Damage in Nuclear Fuel for Advanced Burner Reactors: Modeling and Experimental Validation
Jensen, Niels Gronbech; Asta, Mark; Ozolins, Nigel Browning'Vidvuds; de Walle, Axel van; Wolverton, Christopher
2011-12-29T23:59:59.000Z
The consortium has completed its existence and we are here highlighting work and accomplishments. As outlined in the proposal, the objective of the work was to advance the theoretical understanding of advanced nuclear fuel materials (oxides) toward a comprehensive modeling strategy that incorporates the different relevant scales involved in radiation damage in oxide fuels. Approaching this we set out to investigate and develop a set of directions: 1) Fission fragment and ion trajectory studies through advanced molecular dynamics methods that allow for statistical multi-scale simulations. This work also includes an investigation of appropriate interatomic force fields useful for the energetic multi-scale phenomena of high energy collisions; 2) Studies of defect and gas bubble formation through electronic structure and Monte Carlo simulations; and 3) an experimental component for the characterization of materials such that comparisons can be obtained between theory and experiment.
Modeling radiation-induced mixing at interfaces between low solubility metals
Zhang, Liang, Ph. D. Massachusetts Institute of Technology
2014-01-01T23:59:59.000Z
This thesis studies radiation-induced mixing at interfaces between low solubility metals using molecular dynamics (MD) computer simulations. It provides original contributions on the fundamental mechanisms of radiation-induced ...
Modeling the comfort effects of short-wave solar radiation indoors
Arens, Edward; Hoyt, Tyler; Zhou, Xin; Huang, Li; Zhang, Hui; Schiavon, Stefano
2015-01-01T23:59:59.000Z
2004. [3] Blum HF. Solar heat load, its relationship to theS, Parsons K. The effects of solar radiation on thermalParsons K. The effects of solar radiation and black body re-
CKow -- A More Transparent and Reliable Model for Chemical Transfer to Meat and Milk
Rosenbaum, Ralph K.
2010-01-01T23:59:59.000Z
JRC) Ispra: Italy, 2003. RTI Methodology for predictingbiotransfer factors; RTI Project Number 08860.002.015,regression (hereafter called RTI model) which is recommended
Quantification of colloidal and aqueous element transfer in soils: The dual-phase mass balance model
Bern, CR; Thompson, A; Chadwick, OA
2015-01-01T23:59:59.000Z
1987) Constitutive mass balance relations between chemicalprocesses using mass balance princi- ples. Econ. Geol. 80,and Chorover J. (2011) A mass-balance model to separate and
Modeling of Heat Transfer in Rooms in the Modelica Buildings Library
Wetter, Michael
2013-01-01T23:59:59.000Z
Multizone Air- flow Model in Modelica. ” Edited by ChristianRecent developments of the Modelica buildings library forof the 8-th International Modelica Conference. Modelica
Surface Radiation from GOES: A Physical Approach; Preprint
Habte, A.; Sengupta, M.; Wilcox, S.
2012-09-01T23:59:59.000Z
Models to compute Global Horizontal Irradiance (GHI) and Direct Normal Irradiance (DNI) have been in development over the last 3 decades. These models can be classified as empirical or physical, based on the approach. Empirical models relate ground based observations with satellite measurements and use these relations to compute surface radiation. Physical models consider the radiation received from the earth at the satellite and create retrievals to estimate surface radiation. While empirical methods have been traditionally used for computing surface radiation for the solar energy industry the advent of faster computing has made operational physical models viable. The Global Solar Insolation Project (GSIP) is an operational physical model from NOAA that computes GHI using the visible and infrared channel measurements from the GOES satellites. GSIP uses a two-stage scheme that first retrieves cloud properties and uses those properties in a radiative transfer model to calculate surface radiation. NREL, University of Wisconsin and NOAA have recently collaborated to adapt GSIP to create a 4 km GHI and DNI product every 30 minutes. This paper presents an outline of the methodology and a comprehensive validation using high quality ground based solar data from the National Oceanic and Atmospheric Administration (NOAA) Surface Radiation (SURFRAD) (http://www.srrb.noaa.gov/surfrad/sitepage.html) and Integrated Surface Insolation Study (ISIS) http://www.srrb.noaa.gov/isis/isissites.html), the Solar Radiation Research Laboratory (SRRL) at National Renewable Energy Laboratory (NREL), and Sun Spot One (SS1) stations.
Mehlhorn, Thomas Alan; Kurecka, Christopher J. (University of Michigan, Ann Arbor, MI); McClarren, Ryan (University of Michigan, Ann Arbor, MI); Brunner, Thomas A.; Holloway, James Paul (University of Michigan, Ann Arbor, MI)
2005-11-01T23:59:59.000Z
The original LDRD proposal was to use a nonlinear diffusion solver to compute estimates for the material temperature that could then be used in a Implicit Monte Carlo (IMC) calculation. At the end of the first year of the project, it was determined that this was not going to be effective, partially due to the concept, and partially due to the fact that the radiation diffusion package was not as efficient as it could be. The second, and final year, of the project focused on improving the robustness and computational efficiency of the radiation diffusion package in ALEGRA. To this end, several new multigroup diffusion methods have been developed and implemented in ALEGRA. While these methods have been implemented, their effectiveness of reducing overall simulation run time has not been fully tested. Additionally a comprehensive suite of verification problems has been developed for the diffusion package to ensure that it has been implemented correctly. This process took considerable time, but exposed significant bugs in both the previous and new diffusion packages, the linear solve packages, and even the NEVADA Framework's parser. In order to manage this large suite of problem, a new tool called Tampa has been developed. It is a general tool for automating the process of running and analyzing many simulations. Ryan McClarren, at the University of Michigan has been developing a Spherical Harmonics capability for unstructured meshes. While still in the early phases of development, this promises to bridge the gap in accuracy between a full transport solution using IMC and the diffusion approximation.
Interactive dust-radiation modeling: A step to improve weather Carlos Perez,1
radiative effects could lead to a significant improvement in the radiation balance of numerical weather 2002 is selected to assess the radiative dust effects on the atmosphere at a regional level. A strong unresolved and depend on the optical properties of dust, its vertical distribution, cloud cover, and albedo
Zhao, Tianshou
Simplified model and lattice Boltzmann algorithm for microscale electro-osmotic flows and heat The extremely small length scale of the electric double layer (EDL) of electro-osmotic flows (EOF and temperature as the velocity-slip and temperature-jump boundary conditions, form a simple model for the electro-osmotic
A radiative-convective equilibrium model to study young giant exoplanets by direct imaging
Baudino, J -L; Boccaletti, A; Bonnefoy, M; Lagrange, A M; Galicher, R
2015-01-01T23:59:59.000Z
We developed a model for young giant exoplanets (Exoplanet Radiative-convective Equilibrium Model or Exo-REM). Input parameters are planet's surface gravity (g), effective temperature (Teff ) and elemental composition. Under the additional assumption of thermochemical equilibrium, the model predicts the equilibrium temperature profile and mixing ratio profiles of the most important gases. Opacity sources include the H$_2$-He collision-induced absorption and molecular lines from H$_2$O, CO, CH$_4$ (updated with the Exomol linelist), NH$_3$, VO, TiO, Na and K. Absorption by iron and silicate cloud particles is added above the expected condensation levels with a fixed scale height and a given optical depth at some reference wavelength. Scattering was not included at this stage. We applied Exo-REM to photometric and spectral observations of the planet beta Pictoris b obtained in a series of near IR filters. We derived Teff = 1550 $\\pm$ 150 K, log(g) = 3.5 $\\pm$ 1, and a radius R = 1.76 $\\pm$ 0.24 R Jup (2-$\\sigma...
Analytical modeling for the heat transfer in sheared flows of nanofluids
Ferrari, Claudio; L'vov, Victor S; Procaccia, Itamar; Rudenko, Oleksii; Boonkkamp, J H M ten Thije; Toschi, Federico
2012-01-01T23:59:59.000Z
We developed a model for the enhancement of the heat flux by spherical and elongated nano- particles in sheared laminar flows of nano-fluids. Besides the heat flux carried by the nanoparticles the model accounts for the contribution of their rotation to the heat flux inside and outside the particles. The rotation of the nanoparticles has a twofold effect, it induces a fluid advection around the particle and it strongly influences the statistical distribution of particle orientations. These dynamical effects, which were not included in existing thermal models, are responsible for changing the thermal properties of flowing fluids as compared to quiescent fluids. The proposed model is strongly supported by extensive numerical simulations, demonstrating a potential increase of the heat flux far beyond the Maxwell-Garnet limit for the spherical nanoparticles. The road ahead which should lead towards robust predictive models of heat flux enhancement is discussed.
Analytical modeling for the heat transfer in sheared flows of nanofluids
Claudio Ferrari; Badr Kaoui; Victor S. L'vov; Itamar Procaccia; Oleksii Rudenko; J. H. M. ten Thije Boonkkamp; Federico Toschi
2012-04-12T23:59:59.000Z
We developed a model for the enhancement of the heat flux by spherical and elongated nano- particles in sheared laminar flows of nano-fluids. Besides the heat flux carried by the nanoparticles the model accounts for the contribution of their rotation to the heat flux inside and outside the particles. The rotation of the nanoparticles has a twofold effect, it induces a fluid advection around the particle and it strongly influences the statistical distribution of particle orientations. These dynamical effects, which were not included in existing thermal models, are responsible for changing the thermal properties of flowing fluids as compared to quiescent fluids. The proposed model is strongly supported by extensive numerical simulations, demonstrating a potential increase of the heat flux far beyond the Maxwell-Garnet limit for the spherical nanoparticles. The road ahead which should lead towards robust predictive models of heat flux enhancement is discussed.
A Linear Parabolic Trough Solar Collector Performance Model
Qu, M.; Archer, D.; Masson, S.
2006-01-01T23:59:59.000Z
Collector (PTSC). This steady state, single dimensional model comprises the fundamental radiative and convective heat transfer and mass and energy balance relations programmed in the Engineering Equation Solver, EES. It considers the effects of solar...
MODELING COUPLED PROCESSES OF MULTIPHASE FLOW AND HEAT TRANSFER IN UNSATURATED FRACTURED ROCK
Y. Wu; S. Mukhopadhyay; K. Zhang; G.S. Bodvarsson
2006-02-28T23:59:59.000Z
A mountain-scale, thermal-hydrologic (TH) numerical model is developed for investigating unsaturated flow behavior in response to decay heat from the radioactive waste repository at Yucca Mountain, Nevada, USA. The TH model, consisting of three-dimensional (3-D) representations of the unsaturated zone, is based on the current repository design, drift layout, and thermal loading scenario under estimated current and future climate conditions. More specifically, the TH model implements the current geological framework and hydrogeological conceptual models, and incorporates the most updated, best-estimated input parameters. This mountain-scale TH model simulates the coupled TH processes related to mountain-scale multiphase fluid flow, and evaluates the impact of radioactive waste heat on the hydrogeological system, including thermally perturbed liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature elevations, as well as the changes in water flux driven by evaporation/condensation processes and drainage between drifts. For a better description of the ambient geothermal condition of the unsaturated zone system, the TH model is first calibrated against measured borehole temperature data. The ambient temperature calibration provides the necessary surface and water table boundary as well as initial conditions. Then, the TH model is used to obtain scientific understanding of TH processes in the Yucca Mountain unsaturated zone under the designed schedule of repository thermal load.
Code Number :.............. HEAT TRANSFER QUALIFYING EXAM
Feeny, Brian
is at 40 °C, estimate the heat transfer per unit length by radiation and convection between the twoCode Number :.............. HEAT TRANSFER QUALIFYING EXAM January 2010 OPEN BOOK (only one book) The heat transfer coefficient c) The length of pipe needed for a 35 °C increase in mean temperature d
A covariant model for the gamma N -> N(1535) transition at high momentum transfer
G. Ramalho, M.T. Pena
2011-08-01T23:59:59.000Z
A relativistic constituent quark model is applied to the gamma N -> N(1535) transition. The N(1535) wave function is determined by extending the covariant spectator quark model, previously developed for the nucleon, to the S11 resonance. The model allows us to calculate the valence quark contributions to the gamma N -> N(1535) transition form factors. Because of the nucleon and N(1535) structure the model is valid only for Q^2> 2.3 GeV^2. The results are compared with the experimental data for the electromagnetic form factors F1* and F2* and the helicity amplitudes A_1/2 and S_1/2, at high Q^2.
Grant Hawkes; James E. O'Brien
2008-10-01T23:59:59.000Z
A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in a new novel integrated planar porous-tube supported solid oxide electrolysis cell (SOEC). The model is of several integrated planar cells attached to a ceramic support tube. This design is being evaluated with modeling at the Idaho National Laboratory. 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, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean per-cell area-specific-resistance (ASR) values decrease with increasing current density. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, cathode and anode exchange current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicated 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.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville Power Administration would like submit theNationalto Canada (Million Cubic Feet) Compressedfrom
Wang, Chenxi
2013-07-25T23:59:59.000Z
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...
Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem
Chen, Siyu; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Huang, J.; Huang, Zhongwei; Bi, Jianrong; Zhang, Wu; Shi, Jinsen; Yang, Lei; Li, Deshuai; Li, Jinxin
2014-12-01T23:59:59.000Z
The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust mass balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.
Policastro, A.J.; Pfingston, J.M.; Maloney, D.M.; Wasmer, F.; Pentecost, E.D.
1992-03-01T23:59:59.000Z
The Atmospheric Radiation Measurement (ARM) Program is aimed at supplying improved predictive capability of climate change, particularly the prediction of cloud-climate feedback. The objective will be achieved by measuring the atmospheric radiation and physical and meteorological quantities that control solar radiation in the earth`s atmosphere and using this information to test global climate and related models. The proposed action is to construct and operate a Cloud and Radiation Testbed (CART) research site in the southern Great Plains as part of the Department of Energy`s Atmospheric Radiation Measurement Program whose objective is to develop an improved predictive capability of global climate change. The purpose of this CART research site in southern Kansas and northern Oklahoma would be to collect meteorological and other scientific information to better characterize the processes controlling radiation transfer on a global scale. Impacts which could result from this facility are described.
M. C. M. Cheung; M. Schuessler; T. D. Tarbell; A. M. Title
2008-10-31T23:59:59.000Z
We present results from numerical modeling of emerging flux regions on the solar surface. The modeling was carried out by means of 3D radiative MHD simulations of the rise of buoyant magnetic flux tubes through the convection zone and into the photosphere. Due to the strong stratification of the convection zone, the rise results in a lateral expansion of the tube into a magnetic sheet, which acts as a reservoir for small-scale flux emergence events at the scale of granulation. The interaction of the convective downflows and the rising magnetic flux undulates it to form serpentine field lines emerging into the photosphere. Observational characteristics including the pattern of emerging flux regions, the cancellation of surface flux and associated high speed downflows, the convective collapse of photospheric flux tubes, the appearance of anomalous darkenings, the formation of bright points and the possible existence of transient kilogauss horizontal fields are discussed in the context of new observations from the Hinode Solar Optical Telescope. Implications for the local helioseismology of emerging flux regions are also discussed.
Enhanced convective and film boiling heat transfer by surface gas injection
Duignan, M.R.; Greene, G.A. [Brookhaven National Lab., Upton, NY (United States); Irvine, T.F., Jr. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering
1992-04-01T23:59:59.000Z
Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus_minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured [0 to 8.5 cm/s], the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.
Enhanced convective and film boiling heat transfer by surface gas injection
Duignan, M.R.; Greene, G.A. (Brookhaven National Lab., Upton, NY (United States)); Irvine, T.F., Jr. (State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering)
1992-04-01T23:59:59.000Z
Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured (0 to 8.5 cm/s), the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.
Proceedings of HTSC 2005: Heat Transfer Summer Conference
Guo, Zhixiong "James"
for describing radiation transfer and heat transfer in the micro/nanoscale devices is presented firstProceedings of HTSC 2005: Heat Transfer Summer Conference San Francisco, CA, July 17-22, 2005 HT's equations which govern the propagation of electromagnetic field and the radiation energy transport
Experimental Validation of a Numerical Multizone Airflow and Pollutant Transfer Model
Paris-Sud XI, Université de
and long-term assessment of the performances of ventilation systems, the experimental house MARIA and ventilation systems are modeled in MATLAB/Simulink environment. This paper quickly describes the multi exhaust, balanced and natural ventilation systems. In addition, the virtual laboratory SIMBAD Building
A Dimensionless Model for Predicting the Mass-Transfer Area of Structured Packing
Eldridge, R. Bruce
area Introduction Packing is commonly used in absorption and distillation columns to promote efficient structured packings was measured in a 0.427 m ID column via absorption of CO2 from air into 0.1 kmol/m3 Na structured packing area model is especially critical for the analysis and design of these processes. Wang et
Radiation Chemistry Radiation causes changes in molecules by both
Massey, Thomas N.
Module 4 Radiation Chemistry · Radiation causes changes in molecules by both direct and indirect radiation on the target molecules · Indirect Action - energy transported by chemical species to cause damage or Pyrimidene. · Loss of Purine or Pyrimidine · Free radical transfer causing the loss of base and chain
Effect of translucence of engineering ceramics on heat transfer in diesel engines
Wahiduzzaman, S.; Morel, T. (Integral Technologies, Inc., Westmont, IL (United States))
1992-04-01T23:59:59.000Z
This report describes the experimental portion of a broader study undertaken to assess the effects of translucence of ceramic materials used as thermal barrier coatings in diesel engines. In an earlier analytical work a parametric study was performed, varying several radiative properties over ranges typical of engineering ceramics, thereby identifying the most important radiative properties and their impact on in-cylinder heat transfer. In the current study these properties were experimentally determined for several specific zirconia coatings considered for thermal barrier applications in diesel engines. The methodology of this study involved formulation of a model capable of describing radiative transfer through a semitransparent medium as a function of three independent model parameters, ie, absorption coefficient, scattering coefficient and refractive index. For the zirconia-based ceramics investigated in this study, it was concluded that for usual coating thicknesses (1.5--2.5 mm) these ceramics are optically thick and hence, are effective as radiative heat transfer barriers. These ceramics possess high scattering coefficients and low absorption coefficients causing them to be highly reflective (60-80%) in the spectral region where thermal radiation is important. The performance of the investigated ceramics and the mechanism of heat transfer were found to depend on surface condition, specifically on soot deposition. Thus, to insure the optimum thermal barrier operation for either clean or heavily sooted surfaces, a ceramic material with high scattering coefficient provides the best choice.
Effect of translucence of engineering ceramics on heat transfer in diesel engines. Final report
Wahiduzzaman, S.; Morel, T. [Integral Technologies, Inc., Westmont, IL (United States)
1992-04-01T23:59:59.000Z
This report describes the experimental portion of a broader study undertaken to assess the effects of translucence of ceramic materials used as thermal barrier coatings in diesel engines. In an earlier analytical work a parametric study was performed, varying several radiative properties over ranges typical of engineering ceramics, thereby identifying the most important radiative properties and their impact on in-cylinder heat transfer. In the current study these properties were experimentally determined for several specific zirconia coatings considered for thermal barrier applications in diesel engines. The methodology of this study involved formulation of a model capable of describing radiative transfer through a semitransparent medium as a function of three independent model parameters, ie, absorption coefficient, scattering coefficient and refractive index. For the zirconia-based ceramics investigated in this study, it was concluded that for usual coating thicknesses (1.5--2.5 mm) these ceramics are optically thick and hence, are effective as radiative heat transfer barriers. These ceramics possess high scattering coefficients and low absorption coefficients causing them to be highly reflective (60-80%) in the spectral region where thermal radiation is important. The performance of the investigated ceramics and the mechanism of heat transfer were found to depend on surface condition, specifically on soot deposition. Thus, to insure the optimum thermal barrier operation for either clean or heavily sooted surfaces, a ceramic material with high scattering coefficient provides the best choice.
Verley, Jason C.; Axness, Carl L.; Hembree, Charles Edward; Keiter, Eric Richard; Kerr, Bert (New Mexico Institute of Mining and Technology, Socorro, NM)
2012-04-01T23:59:59.000Z
Photocurrent generated by ionizing radiation represents a threat to microelectronics in radiation environments. Circuit simulation tools such as SPICE [1] can be used to analyze these threats, and typically rely on compact models for individual electrical components such as transistors and diodes. Compact models consist of a handful of differential and/or algebraic equations, and are derived by making simplifying assumptions to any of the many semiconductor transport equations. Historically, many photocurrent compact models have suffered from accuracy issues due to the use of qualitative approximation, rather than mathematically correct solutions to the ambipolar diffusion equation. A practical consequence of this inaccuracy is that a given model calibration is trustworthy over only a narrow range of operating conditions. This report describes work to produce improved compact models for photocurrent. Specifically, an analytic model is developed for epitaxial diode structures that have a highly doped subcollector. The analytic model is compared with both numerical TCAD calculations, as well as the compact model described in reference [2]. The new analytic model compares well against TCAD over a wide range of operating conditions, and is shown to be superior to the compact model from reference [2].
Modeling multiphase heat and mass transfer in consolidated, fractured, porous media
Bixler, N.E.; Eaton, R.R.
1987-12-31T23:59:59.000Z
A number of potential transport mechanisms are considered in this paper: Darcy flow due to pressure and density gradients in the liquid and gas phases; Knudsen diffusion in the gas phase; binary diffusion in the gas phase; heat conduction; energy convection; and evaporation/condensation and its associated latent heat effects. Most of these mechanisms are highly nonlinear, especially Darcy flow, where relative permeabilities often vary by orders of magnitude depending on local saturation, and evaporation/condensation, which depends strongly on local temperature, gas pressure, and saturation. As a consequence of the nonlinearities, it is essential to employ numerical methods if realistic modeling is to be performed. Here, the numerical model is of the standard Galerkin/finite element variety, which is convenient for handling irregular domains and a wide variety of boundary conditions. This numerical model is used to examine the relative effectiveness of each of the transport mechanisms in several one-dimensional and simple two-dimensional multiphase flows in fractured and unfractured porous materials. The importance of fracture orientation is also studied. Predictions are compared with experimental measurements for imbibition and drying of fractured volcanic tuff.
Radiative Properties of Biological Surfaces , J. Preciado1
led researchers to also study the effects of radiation heat transfer1 . Previous research has focused the radiation heat transfer. PROPOSED METHODS Transmission and reflection measurements of single polar bear to determine the radiation heat transfer. #12;ACKNOWLEDGMENTS We are indebted to Dr. Michael Martin of the ALS
Rabindra Nath Das
2007-02-22T23:59:59.000Z
In Radiative transfer, the intensities of radiation from the bounding faces of finite slab are obtained in terms of X- and Y- functions of Chandrasekhar . Those are non linear non homogeneous coupled integral equations . Those non linear integral equations are meromorphically extended to the complex plane to get linear non homogeneous coupled integral equations. Those linear integral equations are converted to linear singular integral equations with. linear constraints . Those singular integral equations are then transformed to non homogeneous Riemann Hilbert Problems. Solutions of those Riemann Hilbert Problems are obtained using the theory of linear singular integral equations to decouple those X- and Y- functions. New forms of linear non homogeneous decoupled integral equations are derived for X- and Y- function separately with new linear constraints. Those new decoupled integral equations are transformed into linear singular integral equations to get two new separate non homogeneous Riemann Hilbert problems and to find solutions in terms of one known N- function and five new unknown functions in complex plane . All five functions are represented in terms of N-functions using the theory of contour integration >. Those X- and Y- functions are finally expressed in terms of that N - function and also in terms of H- functions of Chandrasekhar and of integrals in Cauchy principal value sense in the complex plane and real plane. both for conservative and non conservative cases . The H - functions for semi infinite atmosphere are derived as a limiting case from the expression of X- function of finite atmosphere.
Modeling of Heat and Mass Transfer in Fusion Welding (Book) | SciTech
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect Journal Article:UsingMeson to a J/PsiReactionConnect Book: Modeling of Heat and Mass
Kostic, Milivoje M.
radiation, it is deduced here, that for a conduction heat transfer or mechanical work transfer, there has-energy equivalence [2] and thermal radiation, it is reasoned here that for a conduction heat transfer (e.g., through. It is widely believed that thermal heat conduction and mechanical work transfer are "massless" phenomena [1]. I
Fainman, Yeshaiahu
to heat transfer in ducts and external boundary layers. Introduction to heat conduction and radiation and radiative heat transfer 1.2 Students will be able to recognize applications in which heat transfer transfer by radiation Objective 3 3.1 Students will demonstrate the ability to analyze heat exchangers 3
Pavinich, W.A. [Grove Engineering, Knoxville, TN (United States); Harbison, L.S. [B and W Nuclear Technologies, Lynchburg, VA (United States)
1996-12-31T23:59:59.000Z
The Babcock and Wilcox Owners Group (B and WOG) is embrittlement of Linde 80 reactor vessel welds from a micro-mechanical viewpoint. Previous work that focused on characterizing the large microstructural features indicated that a large portion of the bulk copper content is in precipitate/inclusion/carbide form. This result indicates that copper in solid solution is considerably less than the bulk composition. Field-ion microscope atom probe investigations on unirradiated weld metals with bulk copper contents ranging from 0.22 to 0.38 wt%, also indicate significant amount of copper are tied up in precipitate/inclusion/carbide form. This results is significant since the bulk copper content (which includes both copper in solid solution and copper contained in precipitates, inclusions, and carbides) is used in Regulatory Guide 1.99, Revision 2 to determine radiation damage. This paper reviews these results. Existing radiation embrittlement models superpose the changes in yield strength due to defect clusters and copper-rich precipitates induced by neutron irradiation. Low-copper Linde 80 welds display little or no increase in the 41 joule (30 ft-lb) transition temperature as a result of neutron irradiation which indicates that precipitation is the dominant component of radiation embrittlement for Linde 80 welds. Future work will include further microstructural characterizations of Linde 80 reactor vessel welds and applying the existing radiation embrittlement models to Linde 80 welds. This paper describes the detailed plans for future work.
Salvaggio, Carl
images representing what an airborne or satellite thermal infrared imaging sensor would record. The scene sensors to a point where the model can be usedas a research tool to evaluate the limitations in our infrared (TIR) imagery generated by midwave (3-5 Rm) and longwave (8-14 pm) sensors is being increasingly
ME 339 Heat Transfer ABET EC2000 syllabus
Ben-Yakar, Adela
ME 339 Heat Transfer Page 1 ABET EC2000 syllabus ME 339 Heat Transfer Spring 2010 Required convection; radiation; introduction to phase change heat transfer and to heat exchangers. Prerequisite(s): ME, Fundamentals of Heat and Mass Transfer, 6th ed., Wiley Other Required Material: NA Course Objectives
Radiation Sources and Radioactive Materials (Connecticut)
Broader source: Energy.gov [DOE]
These regulations apply to persons who receive, transfer, possess, manufacture, use, store, handle, transport or dispose of radioactive materials and/or sources of ionizing radiation. Some...
Johnson Jr.,, Ray
6 Year Graduation Model for Full-time Freshmen (Non-SEEK) Students * Students labeled `Not Enrolled' in the charts are either stop outs (may return to QC after a semester off) or drop outs or transfers Graduation Model for Full-time Transfer Students * Students labeled `Not Enrolled' in the charts are either
B. Abdesselam; A. Chakrabarti
2006-07-20T23:59:59.000Z
Statistical models corresponding to a new class of braid matrices ($\\hat{o}_N; N\\geq 3$) presented in a previous paper are studied. Indices labeling states spanning the $N^r$ dimensional base space of $T^{(r)}(\\theta)$, the $r$-th order transfer matrix are so chosen that the operators $W$ (the sum of the state labels) and (CP) (the circular permutation of state labels) commute with $T^{(r)}(\\theta)$. This drastically simplifies the construction of eigenstates, reducing it to solutions of relatively small number of simultaneous linear equations. Roots of unity play a crucial role. Thus for diagonalizing the 81 dimensional space for N=3, $r=4$, one has to solve a maximal set of 5 linear equations. A supplementary symmetry relates invariant subspaces pairwise ($W=(r,Nr)$ and so on) so that only one of each pair needs study. The case N=3 is studied fully for $r=(1,2,3,4)$. Basic aspects for all $(N,r)$ are discussed. Full exploitation of such symmetries lead to a formalism quite different from, possibly generalized, algebraic Bethe ansatz. Chain Hamiltonians are studied. The specific types of spin flips they induce and propagate are pointed out. The inverse Cayley transform of the YB matrix giving the potential leading to factorizable $S$-matrix is constructed explicitly for N=3 as also the full set of $\\hat{R}tt$ relations. Perspectives are discussed in a final section.
Borodovsky, M.
2013-04-11T23:59:59.000Z
Algorithmic methods for gene prediction have been developed and successfully applied to many different prokaryotic genome sequences. As the set of genes in a particular genome is not homogeneous with respect to DNA sequence composition features, the GeneMark.hmm program utilizes two Markov models representing distinct classes of protein coding genes denoted "typical" and "atypical". Atypical genes are those whose DNA features deviate significantly from those classified as typical and they represent approximately 10% of any given genome. In addition to the inherent interest of more accurately predicting genes, the atypical status of these genes may also reflect their separate evolutionary ancestry from other genes in that genome. We hypothesize that atypical genes are largely comprised of those genes that have been relatively recently acquired through lateral gene transfer (LGT). If so, what fraction of atypical genes are such bona fide LGTs? We have made atypical gene predictions for all fully completed prokaryotic genomes; we have been able to compare these results to other "surrogate" methods of LGT prediction.