• It shows the radial component of the incident electric field, which causes the charged particles at the scattering point to exhibit a radial component of acceleration (i.e., a component tangent to the plane of observation). (wikipedia.org)
  • For the ocean part, existing bio-optical models, which correlate the concentration of chlorophyll and the absorption and scattering coefficients of phytoplankton and other matters, have been integrated into this coupled model. (confex.com)
  • where q ∓ = I 0 ∓ /2 are the radiation fluxes in the backward and forward hemispheres, and K λ and S λ are the coefficients of absorption and backscattering, respectively. (thermopedia.com)
  • Using the method of discrete dipole approximation, we calculate the scattering and absorption cross sections of porous particles and derive the blowout size and the behavior of the dust temperature. (aanda.org)
  • We determine the efficiency factors of absorption and the radiation pressure for porous particles, and investigate the influence on the β -ratio. (aanda.org)
  • The characteristics of scattering are insensitive to weak absorption typical for semitransparent materials. (thermopedia.com)
  • It should be noted that a relative mutual independence of absorption and scattering is not a specific property of some semitransparent porous materials, but it is a general behavior of disperse systems containing the so-called optically soft particles which satisfy the conditions of the Rayleigh-Gans theory (see the article Rayleigh-Gans scattering ). (thermopedia.com)
  • 2009). However, strange behavior of the scattering coefficient in the near-infrared range, where the local maxima of scattering appear to be at the wavelength of absorption peaks, is still awaiting the physical explanation. (thermopedia.com)
  • This model should give an explanation of the correlation between the "resonances" of scattering and the spectral peaks of the material absorption. (thermopedia.com)
  • The atmospheric constituents, which are of interest of this thesis, aerosols and clouds, are described, in terms of their types and radiative properties and the main aspects of the scattering and absorption that they induce on the solar radiation, are provided. (upatras.gr)
  • The radiative properties of fibrous media containing glass-wool or carbon or aramid fibers can be modeled using the absorption and scattering characteristics of infinite circular cylinders, which can be randomly oriented or have particular orientations inducing an isotropic or anisotropic structure, respectively. (thermopedia.com)
  • The preceding chapter contains a presentation of several equations, differential and integral ones, describing multiple scatterings of photons. (researchgate.net)
  • In this chapter we generalize to spectral lines formed with partial frequency redistribution, asymptotic methods developed in preceding chapters, when the frequencies of the absorbed and reemitted photons are either unchanged (monochromatic scattering) or completely uncorrelated (complete frequency redistribution). (researchgate.net)
  • In Chap. 20, we derive the thermalization length from a large scale analysis of the integral equation for the source function and in Chap. 21 from the behavior of the random walk of photons that have undergone a large number of scatterings. (researchgate.net)
  • As photons carry momentum and thus can exert pressure there is a maximum possible luminosity at which gravity is able to balance the outward pressure of radiation . (scholarpedia.org)
  • Scattering of photons. (blogspot.com)
  • The x-ray photons can also interact directly with the spin of the electrons, and so they can scatter off the magnetic structure. (lu.se)
  • Monte Carlo refers to a technique first proposed by Metropolis and Ulam to simulate physical processes using a stochastic model.1 In a radiative transport problem, the Monte Carlo method consists of recording photons histories as they are scattered and absorbed. (lu.se)
  • Interaction of a high-intensity optical laser beam with a solid target can generate `hot' electrons, which generate radiation hazards (mainly bremsstrahlung photons and neutrons) from interaction of hot electrons with target and the surrounding materials. (lu.se)
  • Macke A, (1993) Spectral variability of light scattering by atmospheric ice crystals. (tropos.de)
  • Obviously, spectral radiation energy density I λ 0 = g 0 and spectral radiation flux q λ = - h 0 /2. (thermopedia.com)
  • The latter makes it especially important to correctly account for the thermal radiation mode of heat transfer in the porous material, with specific attention to spectral radiative characteristics in the near-infrared. (thermopedia.com)
  • 2009) showed an unusual behavior of the transport scattering coefficient σ λ tr = σ λ (1 - μ ) both in the visible and near-infrared spectral ranges. (thermopedia.com)
  • One can see that the two-flux approximation leads to the typical relations of the diffusion approximation. (thermopedia.com)
  • The absorbed ionizing radiation from cosmic radiation is largely from muons , neutrons, and electrons, with a dose rate that varies in different parts of the world and is based largely on the geomagnetic field, altitude, and solar cycle. (wikipedia.org)
  • Based on the idea of quantum theory, theoretical work on air showers was carried between 1935 and 1940 out by many well-known physicists of the time (including Bhabha , Oppenheimer , Landau , Rossi and others), assuming that in the vicinity of nuclear fields high-energy gamma rays will undergo pair-production of electrons and positrons, and electrons and positrons will produce gamma rays by radiation. (wikipedia.org)
  • Whistler mode chorus waves are particularly important in outer radiation belt dynamics due to their key role in controlling the acceleration and scattering of electrons over a very wide energy range. (jhuapl.edu)
  • The equations of two-flux approximation can be formally derived for the arbitrary scattering function, and the resulting formulation will include some characteristics of the scattering function (Brewster and Tien, 1982). (thermopedia.com)
  • Our study is based on the results of extensive computations of different characteristics of electromagnetic scattering obtained by using the superposition T-matrix method which represents a direct computer solver of the macroscopic Maxwell equations for an arbitrary multisphere configuration. (nasa.gov)
  • This makes it possible to obtain an explicit relationship between the scattering characteristics and the parameters of the water surface, which opens possibilities for creating new algorithms for solving the inverse problem of retrieving wave parameters. (wdcb.ru)
  • An algorithm is proposed for determining the direction of wave propagation from measurements of the DS characteristics of reflected radiation. (wdcb.ru)
  • be able to decide the symmetry characteristics of diatomic and some simple polyatomic molecules based on analysis of different spectra for IR and Raman scattering. (lu.se)
  • Lee et al (1990), based on the pseudo-differential operator approach put forward by Engquist and Majda (1977), derived a second order absorbing boundary condition for an elliptic boundary equivalent to the BGT damper and used it in electromagnetic wave scattering problems by the finite difference method. (iitm.ac.in)
  • The accurate description of the radiation transfer within a vegetation layer is complicated by the fact that both of these coefficients depend on the position of the external sources of radiation, and by the lack of precise knowledge about the radiative boundary conditions at the top and bottom of this layer. (ametsoc.org)
  • The fibers of ordinary thermal insulation, such as glass or carbon or aramid fibers, can be considered as being infinitely long circular cylinders because their length (a few millimeters) is much greater than the radiation wavelength and their diameter varies from 1 to 15 μm. (thermopedia.com)
  • Macke A, Mishchenko M-I (1996) Applicability of regular particle shapes in light scattering calculations for atmospheric ice particles. (tropos.de)
  • The physical environments that might pose risks to crew safety on Mars fall into three categories: geologic, atmospheric, and radiation. (nationalacademies.org)
  • The radiative transfer theory is described, along with various approximations, used to address specific atmospheric transfer problems. (upatras.gr)
  • The emphasis is placed on the specificities of this problem when it is addressed with the radiation transfer equation classically used in atmospheric sciences. (ametsoc.org)
  • To facilitate the solution of the radiative coupling between the vegetation and atmospheric layers, the same formal approach is used in both media, and the extinction and differential scattering coefficients are specified in a similar way. (ametsoc.org)
  • The dependence of the radiative properties on the incident radiation direction increases the complexity of the radiative transfer problem. (thermopedia.com)
  • Kamdem Tagne and Baillis (2010) showed that radiative heat transfer through anisotropic medium can be analyzed using simplified models of an anisotropic medium or an equivalent isotropic medium with average radiative properties and an isotropic or Henyey-Greenstein scattering phase function. (thermopedia.com)
  • The radiative properties identification method requires experimental and theoretical data for both transmittance and reflectance obtained for the collimated incident radiation on a sample. (thermopedia.com)
  • Diffraction imaging techniques using synchrotron radiation can reveal small strains down to 10 -4 -10 -5 . (lu.se)
  • It includes a theoretical background of the scattering mechanisms in Thomson scattering in nano-crystals, goes through the formalism for coherent diffraction imaging, crystal structure and deformation in nanoobjects and the technical aspects of the experimental setup and measurement. (lu.se)
  • The Bayliss, Gunzberger and Turkel (BGT) boundary dampers (1982), which require a circular cylindrical truncation boundary in the diffraction-radiation problem of water waves, have been particularly successful in this task. (iitm.ac.in)
  • Modeling of Electromagnetic Scattering by Discrete and Discretely Heterogeneous. (nasa.gov)
  • In this paper, we discuss some aspects of numerical modeling of electromagnetic scattering by discrete random medium by using numerically exact solutions of the macroscopic Maxwell equations. (nasa.gov)
  • In a domain method of solution of exterior scalar wave equation, the radiation condition needs to be imposed on a truncation boundary of the modeling domain. (iitm.ac.in)
  • The performance of the damper on elliptic truncation boundary is established using an example of radiation by a floating semi-ellipsoid by studying its hydrodynamic added mass and damping coefficients. (iitm.ac.in)
  • The high flux of coherent X-ray beams from synchrotron radiation facilities, combined with the nano-focus capabilities developed in recent years, have made it possible to probe nano-crystals. (lu.se)
  • To this end, we use a wide range of neutron facilities and synchrotron radiation facilities in Europe and around the world, soon to include the European Spallation Source at Lund. (lu.se)
  • Thomson scattering is the elastic scattering of electromagnetic radiation by a free charged particle, as described by classical electromagnetism. (wikipedia.org)
  • Thomson scattering is an important phenomenon in plasma physics and was first explained by the physicist J. J. Thomson. (wikipedia.org)
  • The overall time step is 20 minutes for dynamics and physics, except for shortwave and longwave radiative fluxes and heating rates, which are calculated hourly (with longwave absorptivities and emissivities updated every 12 hours--see Radiation ). (llnl.gov)
  • In 1933, shortly after the discovery of cosmic radiation by Victor Hess , Bruno Rossi [3] conducted an experiment in the Institute of Physics in Florence, using shielded Geiger counters to confirm the penetrating character of the cosmic radiation. (wikipedia.org)
  • Accretion disc physics is thus governed by a non-linear combination of many processes, including gravity, hydrodynamics, viscosity, radiation and magnetic fields. (scholarpedia.org)
  • The scattering coefficient σ λ and asymmetry factor of scattering μ can usually be predicted by analysis of the material morphology. (thermopedia.com)
  • The three parameters necessary to feed radiative transfer models, namely, extinction, asymmetry parameter, and single scattering albedo, can all be set by the analytical model, with explicit dependence on a few parameters. (springer.com)
  • In this case, the total scattering and the extinction cross sections determine the single scattering albedo, which agrees with numerical simulations. (springer.com)
  • The resulting form is used for the numerical evaluation of the scattering integral. (jpier.org)
  • Thermodynamic, hydrodynamic, scattering and separation methods for investigation and characterization of polymer systems are described. (vscht.cz)
  • When a particle of the cosmic radiation, which could be a proton , a nucleus , an electron , a photon , or (rarely) a positron , interacts with the nucleus of a molecule in the atmosphere, it produces a vast number of secondary particles, which make up the shower. (wikipedia.org)
  • We focus on using scattering techniques to look at the structure and dynamics associated with these strong electron corrrelations, particularly neutron and X-ray methods. (lu.se)
  • To reduce electron losses and decrease radiation levels around the syn-chrotron, optimizations of the electron beam during injection into the storage ring, ramping and standard operation were carried out. (lu.se)
  • In the low-energy limit, the electric field of the incident wave accelerates the charged particle, causing it, in turn, to emit radiation at the same frequency as the incident wave, and thus the wave is scattered. (wikipedia.org)
  • 15 The particle will move in the direction of the oscillating electric field, resulting in electromagnetic dipole radiation. (wikipedia.org)
  • The moving particle radiates most strongly in a direction perpendicular to its acceleration and that radiation will be polarized along the direction of its motion. (wikipedia.org)
  • It is especially important to take into account the contribution of the grains or particle aggregates, pores, and cracks of size comparable with the radiation wavelength. (thermopedia.com)
  • The importance of a refined description of the particle composition and structure, going beyond mean-field approximations, is generally recognized. (springer.com)
  • The model can be tightly compared to measurements with single particle extinction and scattering and spectrophotometry and suggests a simple behavior for 90° scattering from fractal aggregates as a function of extinction, which is also confirmed experimentally and numerically. (springer.com)
  • this applies especially to particle sizes close to the radiation wavelength (Nousiainen et al. (springer.com)
  • The efficiency of wave-particle resonant interactions is defined by whistler wave properties which have been described by the approximation of plane linear waves propagating through the cold plasma of the inner magnetosphere. (jhuapl.edu)
  • In the same way, in the field of radiation science, we welcome, among other things, topics in the area of electromagnetic radiation, ionizing radiation, neutron radiation, or black-body radiation. (mdpi.com)
  • To measure the effects of high pressure using neutron scattering presents some difficulties, as relatively large samples are required to get a good signal-to-noise ratio, and because the pressure cells generate a lot of background scattering. (lu.se)
  • We are working with collaborators at KTH (Patrik Henelius) and ESS (Pascale Deen, Malcolm Guthrie, Rasmus Toft-Petersen) to develop new uniaxial and hydrostatic pressure cells, optimized for neutron scattering at the ESS, on a project funded by VR. (lu.se)
  • The Lund Institute of Advanced Neutron and X-ray Science ( LINXS ) is organizing its first thematic workshop titled Scattering and Dynamics of Flowing Soft Material. (lu.se)
  • The most information valuable one of these methods is X-ray diffuse scattering which allows analyzing the distribution of scattered X-ray waves in the vicinity of the reciprocal lattice site. (pensoft.net)
  • Approximation Methods. (blogspot.com)
  • We propose a method for efficient evaluation of surface integrals arising in boundary element methods for three-dimensional Helmholtz problems (with real positive wavenumber k), modelling wave scattering and/or radiation in homogeneous media. (reading.ac.uk)
  • METHODS: A total of 35 consecutive patients, prospectively recruited within a study registry, who received IORT following BM resection at a single neuro-oncological center were evaluated for radiation necrosis (RN) incidence rates, local control rates (LCR), distant brain progression (DBP) and overall survival (OS) as long-term outcome parameters. (bvsalud.org)
  • METHODS: Lateral dose profile and output measurements of three proton beam delivery techniques (pencil beam scanning, pencil beam scanning combined with collimators, passive scattering with collimators) were performed using high-resolution EBT3 films, a PinPoint 3D 31022 ionization chamber, a microSilicon diode 60023 and a microDiamond detector 60019 (all PTW Freiburg, Germany). (bvsalud.org)
  • 2010), we consider a new physical model of resonance behavior of scattering of nanoporous silica. (thermopedia.com)
  • As a result, thermal radiation may proivide an important contribution to heat transfer through this highly porous material. (thermopedia.com)
  • Effective solutions to the radiation transfer problem in plant canopies require the introduction of specific hypotheses, for instance, in the treatment of the multiple scattering contribution. (ametsoc.org)
  • This paper discusses the problem of radiation transfer in geophysical media, in particular, within homogeneous plant canopies over terrestrial surfaces. (ametsoc.org)
  • Instrument measurements and model calculations are subsequently used to derive the aerosol single scattering albedo at low UV-A and at UV-B wavelengths. (upatras.gr)
  • The simplest approximation for one-dimensional radiative transfer problems in a plane-parallel layer of absorbing and scattering medium is based on the assumption of isotropic radiation intensity over the forward and backward hemispheres. (thermopedia.com)
  • As shown by S. Chandrasekhar in 1946, the Milne problem for conservative Rayleigh scattering in a plane-parallel semi-infinite medium has an exact solution and the emergent polarized radiation field can be expressed in terms of two auxiliary functions H l(μ) and H r(μ), with explicit expressions. (researchgate.net)
  • Macke A, (1993) Scattering of light by polyhedral ice crystals. (tropos.de)
  • Analytical processing of experimental reflection curves and reciprocal space maps allowed determination of complex microdefect structures in silicon [ 4 , 5 ] and garnet [ 6 , 7 ] crystals exposed to radiation. (pensoft.net)
  • It is shown that this radiation model is computational efficient and at the same time can achieve acceptable accuracy for flux and heating rate calculations in the atmosphere and the oceans. (confex.com)
  • This paper discusses internal reflection of a photon at boundaries, shows how the phase function may be used to generate new scattering angles, discusses a few variance reduction schemes to improve efficiency, gives a method for estimating the uncertainty in any Monte Carlo calculation, and gives results for validating the Monte Carlo implementation. (lu.se)
  • Using the principle of stationary phase, we can approximate the propagation over a terrain (the PO approximation of the vector problem with a 3-D surface) with a 2-D surface. (intechopen.com)
  • We use it, in particular, to distinguish between ordinary and anomalous diffusion processes, to introduce the thermalization length as a characteristic scale of variation of the radiation field and to introduce new equat. (researchgate.net)
  • be able to describe how a molecule interacts with electromagnetic radiation via electric dipole transitions and Raman scattering processes. (lu.se)
  • Two body Collisions - scattering in laboratory and Centre of mass frames. (ugcnetd.com)
  • Compute the spacecraft temperature from the direct solar radiation, albedo, and planet infrared flux as well as the radiative heat transfer between various spacecraft parts. (comsol.com)
  • Browse subject: Solar radiation -- Charts, diagrams, etc. (upenn.edu)
  • Solar radiation -- Charts, diagrams, etc. (upenn.edu)
  • This thesis is focused on the aerosols and clouds optical properties and the effects that these parameters have on the solar radiation transfer in the atmosphere. (upatras.gr)
  • In this Chapter, we use the integral equation for the source function to determine large scale properties of the radiation field. (researchgate.net)
  • Topics include organization, site, accelerators and beamlines as well as designation of areas, radiation monitors, dosimetry and the personnel safety system. (lu.se)
  • Therefore, it is also convenient to simplify the scattering function by the use of isotropic or Henyey-Greenstein approximations. (thermopedia.com)
  • These models can be classified into two groups in which the scattering phase function is considered to be either (1) isotropic or (2) anisotropic. (thermopedia.com)
  • The isotropic or Henyey-Greenstein scattering phase functions can be used in the inverse problem solution using the directional-hemispherical transmittance and reflectance only when the medium is optically thick and purely scattering (Kamdem Tagne, 2008). (thermopedia.com)
  • In this paper, this boundary condition is implemented in the form of a boundary damper approximation in the context of the finite element method and used in solving water wave radiati on of a floating body. (iitm.ac.in)
  • It is the low-energy limit of Compton scattering: the particle's kinetic energy and photon frequency do not change as a result of the scattering. (wikipedia.org)
  • SIMION's scope does not, at least currently in itself cover high-frequency ( HF ) radiation problems and certain more advanced types of magnetic problems, though these are expanding. (simion.com)
  • Coherent Doppler lidars are also capable of measuring the projection of the air mass velocity on the sounding axis by detecting the Doppler shift of the radiation frequency during heterodyne reception [1-3]. (photonics.su)
  • We also discuss the case of absorbing particles and report the experimental results for water suspensions of black carbon for both the forward and 90° scattering properties. (springer.com)
  • In this article, we follow the majority of the publications and use the name "two-flux approximation" for this model. (thermopedia.com)
  • The two-flux approximation is usually used for isotropically scattering media. (thermopedia.com)
  • Obviously, the two-flux approximation can also be employed in one-dimensional problems with axial or spherical symmetry (Rekin, 1978). (thermopedia.com)
  • Kubelka, 1948), the phenomenological two-flux model (irrespective of the RTE) has been proposed for analyzing the reflectance and transmittance of paint layers or other scattering coatings. (thermopedia.com)
  • According to the four-flux model, two additional collimated components of the radiation are introduced in the forward and backward directions. (thermopedia.com)
  • An intensive radiation measurement using online and passive radiation monitoring were taken places around foreseen hot spots and in general places around both tunnels. (lu.se)
  • Blowout sizes are calculated for various stellar luminosities and porosities, and an approximation equation is derived to estimate the blowout size as a function of these parameters. (aanda.org)
  • The estimated monthly averages of the Brewer single scattering albedo at 320 nm are in very close agreement (within ±0.01) with measurements at 440nm from a collocated CIMEL sunphotometer. (upatras.gr)
  • It addresses these concerns by validating the measurements taken at the perimeter air monitoring station #46 (located in the Scarboro community) and external gamma data collected during past aerial radiation surveys. (cdc.gov)
  • this paper is tackling the radiation measurements during Storage Ring operation at 200mA, 2.5GeV. (lu.se)
  • Radiation measurements results received before and after the chopper installation in the linac and additionally problems with radiation levels while the beam current is increasing to the designed 500mA value will be presented. (lu.se)
  • Therefore, depending on where an observer is located, the light scattered from a small volume element may appear to be more or less polarized. (wikipedia.org)
  • Macke A,Tzschichholz F (1992) Scattering of light by two-dimensional deterministic Koch islands. (tropos.de)
  • Macke A, Mishchenko M-I, Miunonen K, Carlson B-E (1995) Scattering of light by large nonspherical particles: ray tracing approximation versus T-matrix method. (tropos.de)
  • Macke A, Mishchenko M-I, Cairns B (1996) The influence of inclusions on light scattering by large ice particles. (tropos.de)
  • The specifics of paint coatings become important when taking into account the light refraction at the coating/air interface (which is the so-called Saunderson correction) (Saunderson, 1942) and possible illumination of the interface by a collimated external radiation. (thermopedia.com)
  • In the first interactions of the cascade especially hadrons (mostly light mesons like pions and kaons ) are produced and decay rapidly in the air, producing other particles and electromagnetic radiation, which are part of the shower components. (wikipedia.org)
  • This exercise is particularly simple and transparent if one writes the graviton emission rate in a form that separates the response of the thermal nuclear medium from the phase space of the radiation. (arxiv-vanity.com)
  • Such solutions are of interest for the development of the method of diagnosing coarsely dispersed media from multiply scattered radiation treated in the small-angle approximation. (iao.ru)
  • This method, which uses METEOSAT imagery and routine surface global radiation measurement is shown to be relevant for climatological studies. (ametsoc.org)
  • Once launched, the photon is moved a distance s where it may be scattered, absorbed, propagated undisturbed, internally reflected, or transmitted out of the tissue. (lu.se)
  • If the weight is above a minimum, then the rest of the photon packet is scattered into a new direction and the process is repeated. (lu.se)
  • Analyze heat transfer by conduction, convection, and radiation with the Heat Transfer Module, an add-on product to the COMSOL Multiphysics ® simulation platform. (comsol.com)
  • All of the capabilities in the Heat Transfer Module are based on the three modes of heat transfer: conduction, convection, and radiation. (comsol.com)
  • As a result, in particular, we clarify the range of applicability of the low-density theories of radiative transfer and coherent backscattering as well as of widely used effective-medium approximations. (nasa.gov)
  • Here, we use equivalent contour integrals developed for aperture scattering in optics to reduce this requirement to O(k), and possible extensions to reduce it further to O(1)are identified. (reading.ac.uk)
  • Shear and extensional flow fields are ubiquitous in the manufacture, processing and use of these everyday materials and yet, typical experimental techniques, like small angle scattering, only provide information about the quiescent or time-averaged state. (lu.se)
  • Radiation Theory. (blogspot.com)
  • In addition, the scattering phase function obtained using the Mie theory may undergo strong angular oscillations and is characterized by a strong forward scattering peak. (thermopedia.com)
  • To reduce the number of degrees of freedom required when k is large, a common approach is to include in the approximation space oscillatory basis functions, with support extending across many wavelengths. (reading.ac.uk)