Light Scattering by Irregularly Shaped Particles

Light Scattering by Irregularly Shaped Particles PDF Author: Schuerman
Publisher: Springer Science & Business Media
ISBN: 1468437046
Category : Technology & Engineering
Languages : en
Pages : 335

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Book Description
This volume contains most of the invited papers presented at the International Workshop on Light Scattering by Irregularly Shaped Particles held on June 5-7, 1979. at the State University of New York at Albany (SUNYA). Over seventy participants representing many dis ciplines convened to define some of the ever-increasing number of resonant light-scattering problems associated with particle shape and to relate their most recent investigations in this field. It is obvious from the two introductory papers that an investi gator's primary discipline determines his/her approach to the light scattering problem. The meteorologist, Diran Deirmendjian, advocates an empirical methodology: to model the scattering by atmospheric aerosols, using equivalent spheres as standards, in the most effi cient and simplest manner that is consistent with remote sensing, in situ, and laboratory· data. Because of the almost infinite variety of particle shapes, he questions not only the possibility but even the usefulness of the exact solution of scattering by a totally arbitrary particle. The astrophysicist, J. Mayo Greenberg, is primarily concerned with the information content carried by the scattered light because this radiation is the sole clue to under standing the nature of interstellar dust. What measurements (polar ization, color dependence, etc ••• ) should be made to best determine a given particle characteristic (size, surface roughness, refractive index, etc ••• )? Thus, he considers the physics of the scattering process to be of paramount interest.

Light Scattering by Irregularly Shaped Particles

Light Scattering by Irregularly Shaped Particles PDF Author: Schuerman
Publisher: Springer Science & Business Media
ISBN: 1468437046
Category : Technology & Engineering
Languages : en
Pages : 335

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Book Description
This volume contains most of the invited papers presented at the International Workshop on Light Scattering by Irregularly Shaped Particles held on June 5-7, 1979. at the State University of New York at Albany (SUNYA). Over seventy participants representing many dis ciplines convened to define some of the ever-increasing number of resonant light-scattering problems associated with particle shape and to relate their most recent investigations in this field. It is obvious from the two introductory papers that an investi gator's primary discipline determines his/her approach to the light scattering problem. The meteorologist, Diran Deirmendjian, advocates an empirical methodology: to model the scattering by atmospheric aerosols, using equivalent spheres as standards, in the most effi cient and simplest manner that is consistent with remote sensing, in situ, and laboratory· data. Because of the almost infinite variety of particle shapes, he questions not only the possibility but even the usefulness of the exact solution of scattering by a totally arbitrary particle. The astrophysicist, J. Mayo Greenberg, is primarily concerned with the information content carried by the scattered light because this radiation is the sole clue to under standing the nature of interstellar dust. What measurements (polar ization, color dependence, etc ••• ) should be made to best determine a given particle characteristic (size, surface roughness, refractive index, etc ••• )? Thus, he considers the physics of the scattering process to be of paramount interest.

A Systematic Study of Light Scattering by Irregularly Shaped Particles

A Systematic Study of Light Scattering by Irregularly Shaped Particles PDF Author: R. T. Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 16

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Book Description
This final report summarizes the research activities under the 'Systematic Study of Light Scattering by Irregularly Shaped Particles.' The beginning one and one-half years were devoted to the analysis of existing experimental data and the related theoretical light-scattering studies, in parallel with the reconstruction, renovation and calibration of the microwave analog scattering facility then relocated from the Albany, N.Y. area. The following one and one-half year period was devoted to actual measurement tasks and analysis of data in our original proposal; e.g., the investigations of scattering by interacting spheres and by particles with rough surfaces. Simultaneous with these measurements a number of 2:1 finite cylinders were also measured on their extinction properties when they were either preferentially or randomly oriented in space.

Light Scattering by Irregularly Shaped Particles

Light Scattering by Irregularly Shaped Particles PDF Author: International Workshop on Light Scattering by Irre
Publisher:
ISBN: 9780608054346
Category :
Languages : en
Pages : 344

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Book Description


Light Scattering by Irregularly Shaped Particles

Light Scattering by Irregularly Shaped Particles PDF Author: 3Island Press
Publisher:
ISBN: 9781468437058
Category :
Languages : en
Pages : 348

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Book Description


Light Scattering Studies of Irregularly Shaped Particles

Light Scattering Studies of Irregularly Shaped Particles PDF Author: Yuli Wang Heinson
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
We present light scattering studies of irregularly shaped particles which significantly affect the climate. We built and calibrated our apparatus which was able to measure all six independent scattering matrix elements. Our apparatus detects light from 0.32° to 157° simultaneously. We studied all six scattering matrix elements of irregularly shaped Arizona Road Dust which behave differently than those of spheres. We strongly focused on the most important scattering matrix element -- the phase function, scattered intensity vs. the scattering angle, which we applied Q-space analysis to. Q-space analysis involves plotting the scattering intensity vs. the magnitude of the scattering wave vector q or qR with R the radius of a particle, on a double logarithmic scale. We measured and studied the phase functions of Al2O3 abrasives; compared the scattering from the abrasives with the scattering of spheres. To generalize the study, we collected a large amount of experimental and theoretical data from our group and others and applied Q-space analysis. They all displayed a common scattering pattern. The power law exponents showed a quasi-universal functionality with the internal coupling parameter [rho]ʹ. In situ studies of the soot fractal aggregates produced from a burner were also conducted. A power law exponent -1.85 is seen to imply the aggregates have fractal dimension of D[subscript f]=1.85. The overall work presented shows Q-space analysis uncovers patterns common to all particles: a q-independent forward scattering regime is followed by a Guinier regime, a power law regime, and sometimes an enhanced back scattering regime. The description of the patterns applies to spheres as well, except the power law regime has more than a single power law. These simple patterns give a unified description for all particle shapes. Moreover, the power law exponents have a quasi-universal functionality with [rho]ʹ for non-fractal aggregates. The absolute value of the exponents start from 4 when [rho]ʹ is small. As [rho]ʹ increases, the exponents decrease until the trend levels off at [rho]ʹ[greater-than or equivalent to]10 where the exponents reach a constant 1.75±0.25. All the non-fractal particles fall on the same trend regardless of the detail of their structure.

Light Scattering Reviews 4

Light Scattering Reviews 4 PDF Author: Alexander A. Kokhanovsky
Publisher: Springer Science & Business Media
ISBN: 354074276X
Category : Science
Languages : en
Pages : 516

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Book Description
This fourth volume of Light Scattering Reviews is composed of three parts. The ?rstpartisconcernedwiththeoreticalandexperimentalstudiesofsinglelightsc- tering by small nonspherical particles. Light scattering by small particles such as, for instance, droplets in the terrestrial clouds is a well understood area of physical optics. On the other hand, exact theoretical calculations of light scattering p- terns for most of nonspherical and irregularly shaped particles can be performed only for the restricted values of the size parameter, which is proportional to the ratio of the characteristic size of the particle to the wavelength?. For the large nonspherical particles, approximations are used (e. g. , ray optics). The exact th- retical techniques such as the T-matrix method cannot be used for extremely large particles, such as those in ice clouds, because then the size parameter in the v- iblex=2?a/???,wherea is the characteristic size (radius for spheres), and the associated numerical codes become unstable and produce wrong answers. Yet another problem is due to the fact that particles in many turbid media (e. g. , dust clouds) cannot be characterized by a single shape. Often, refractive indices also vary. Because of problems with theoretical calculations, experimental (i. e. , la- ratory) investigations are important for the characterization and understanding of the optical properties of such types of particles. The ?rst paper in this volume, written by B. Gustafson, is aimed at the descr- tionofscaledanalogueexperimentsinelectromagneticscattering.

Light Scattering Study of Irregular Particles with Arbitrary Size, Shape, and Complex Refractive Index

Light Scattering Study of Irregular Particles with Arbitrary Size, Shape, and Complex Refractive Index PDF Author: Prakash Gautam
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
We investigated light scattering due to irregularly shaped aerosol particles with diverse shapes, sizes, and complex refractive indices. We have designed and developed a light scattering setup based on a novel optical scheme that can detect light from 0.32° and 177.6°, from an extreme forward to the backscattering regime, involving 46 angles. Our setup was able to measure all six independent scattering matrix elements; however, we focused on measuring the scattering intensity and the linear depolarization ratio for different dust particles. Given the extremely small and large angles, the data obtained for our setup are plotted on both: versus scattering angle, [theta] linearly, and scattering wave vector, q or qR with R the radius of a particle, on a log-log scale, called [theta] and Q-space respectively. The Q- space analysis best represents the data at the extreme forward scattering regime; however, it compresses the data at the large scattering angles, [theta] , where useful data also reside. At large scattering angles, the scattered intensity is best viewed by [theta]-space analysis. We scattered the light from different aerosol particles viz; silicon dioxide (SiO2), aluminum abrasive (Al2O3), a highly refractive molybdenum disulfide (MoS2), a highly absorptive hematite particle ([alpha]--Fe2O3), arizona road dust and Soot particles. The measured scattered intensity was interpreted by applying both analysis methods. Light scattering for all particle types was compared to theoretical Mie scattering calculations using size distributions determined by an Aerodynamic Particle Sizer (APS 3321), an aerosol measuring instrument. The compared results between the experimentally measured data and Mie calculations showed a close agreement at the forward scattering regime and poorly at the side and backscattering regimes. Effects of the intensity-weighted size distribution were discussed. We applied Guinier analysis on light scattering measured data to compare light scattering inferred size to the intensity-weighted mean sizes for all shape particles. The light scattering sizes were consistent with the intensity-weighted mean sizes of reasonable accuracy for any shape and refractive index. This result has demonstrated the importance of intensity weighting of the size distribution in light scattering. We measured and studied the linear depolarization ratio for different dust particles. They all displayed a common pattern. The measured values were negligibly small at the forward scattering regime. They increased with increasing the scattering angle and reached a maximum at the side scattering regime that generally droped off at the backscattering regime. The effects of particle asphericity, size, and refractive index on the linear depolarization ratio were investigated. We further investigate the light scattering from fractal soot and non-fractal hematite aggregates. The results showed an enhancement in the backscattering despite a large imaginary refractive index. We found that enhancement backscattering for the non-fractal aggregate is due to internal multiple scattering between the grains within the aggregate. In contrast, enhancement backscattering is yet to be understood for fractal soot aggregates. Furthermore, the results presented in this work showed the sensitive of light backscattering with the change in particles' shapes, sizes, and refractive indices and warn the experimentalist to use the backscattering measured data with great caution.

Light Scattering by Nonspherical Particles

Light Scattering by Nonspherical Particles PDF Author: Michael I. Mishchenko
Publisher: Elsevier
ISBN: 0080510205
Category : Science
Languages : en
Pages : 721

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Book Description
There is hardly a field of science or engineering that does not have some interest in light scattering by small particles. For example, this subject is important to climatology because the energy budget for the Earth's atmosphere is strongly affected by scattering of solar radiation by cloud and aerosol particles, and the whole discipline of remote sensing relies largely on analyzing the parameters of radiation scattered by aerosols, clouds, and precipitation. The scattering of light by spherical particles can be easily computed using the conventional Mie theory. However, most small solid particles encountered in natural and laboratory conditions have nonspherical shapes. Examples are soot and mineral aerosols, cirrus cloud particles, snow and frost crystals, ocean hydrosols, interplanetary and cometary dust grains, and microorganisms. It is now well known that scattering properties of nonspherical particles can differ dramatically from those of "equivalent" (e.g., equal-volume or equal-surface-area) spheres. Therefore, the ability to accurately compute or measure light scattering by nonspherical particles in order to clearly understand the effects of particle nonsphericity on light scattering is very important. The rapid improvement of computers and experimental techniques over the past 20 years and the development of efficient numerical approaches have resulted in major advances in this field which have not been systematically summarized. Because of the universal importance of electromagnetic scattering by nonspherical particles, papers on different aspects of this subject are scattered over dozens of diverse research and engineering journals. Often experts in one discipline (e.g., biology) are unaware of potentially useful results obtained in another discipline (e.g., antennas and propagation). This leads to an inefficient use of the accumulated knowledge and unnecessary redundancy in research activities. This book offers the first systematic and unified discussion of light scattering by nonspherical particles and its practical applications and represents the state-of-the-art of this important research field. Individual chapters are written by leading experts in respective areas and cover three major disciplines: theoretical and numerical techniques, laboratory measurements, and practical applications. An overview chapter provides a concise general introduction to the subject of nonspherical scattering and should be especially useful to beginners and those interested in fast practical applications. The audience for this book will include graduate students, scientists, and engineers working on specific aspects of electromagnetic scattering by small particles and its applications in remote sensing, geophysics, astrophysics, biomedical optics, and optical engineering. The first systematic and comprehensive treatment of electromagnetic scattering by nonspherical particles and its applications Individual chapters are written by leading experts in respective areas Includes a survey of all the relevant literature scattered over dozens of basic and applied research journals Consistent use of unified definitions and notation makes the book a coherent volume An overview chapter provides a concise general introduction to the subject of light scattering by nonspherical particles Theoretical chapters describe specific easy-to-use computer codes publicly available on the World Wide Web Extensively illustrated with over 200 figures, 4 in color

Scattering, Absorption, and Emission of Light by Small Particles

Scattering, Absorption, and Emission of Light by Small Particles PDF Author: Michael I. Mishchenko
Publisher: Cambridge University Press
ISBN: 9780521782524
Category : Science
Languages : en
Pages : 562

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Book Description
A thorough and up-to-date treatment of electromagnetic scattering by small particles.

Light Scattering Reviews, Vol. 6

Light Scattering Reviews, Vol. 6 PDF Author: Alexander A. Kokhanovsky
Publisher: Springer Science & Business Media
ISBN: 3642155316
Category : Science
Languages : en
Pages : 353

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Book Description
This is the next volume in series of Light Scattering Reviews. Volumes 1-5 have already been printed by Springer. The volume is composed of several papers ( usually, 10) of leading researchers in the respective field. The main focus of this book is light scattering, radiative transfer and optics of snow.